PORTABLE VACUUM CLEANERS.
Power Required 228
Weight of Efficient Portable Cleaners 228
Limit of Power Consumption When Attached to Lighting System 229
Disadvantage of Having Dust Bag at Outlet of Fan 230
Portables Equipped with Mechanically-Operated Brushes 231
Portables Exhausting Air Inside of Building 231
TABLES.
PAGE
1. Cleaning Tests of Dirty Carpets 34
2. Cleaning Tests of Carpets Filled with Quicksand 38
3. Cleaning Tests Using 1 oz. of Sand per Square Yard of Carpet 40
4. Comparison of Tests Made by Mr. Reeve and by the Author 48
5. Effort Necessary to Operate Cleaning Tools 51
6. Vacuum Required at Hose Cock to Operate Type A Renovators
Attached to Varying Lengths of Different-Sized Hose 89
7. Air Quantities and Vacuum at Renovator with 1-in. Hose and 10
in. Vacuum at Hose Cock 90
8. Air Quantities and Vacuum at Renovator with 1¹⁄₄-in. Hose and
6 in. Vacuum at Hose Cock 90
9. Vacuum Required at Hose Cock to Operate Type C Renovators with
Various Lengths of Three Sizes of Hose 91
10. Air Quantities Through Floor Brush with Various Sizes and
Lengths of Hose, Operated on Same System with Type A
Renovators 92
11. Horse Power Required at Hose Cock to Operate Bare Floor
Brushes on Same System with Type A Renovators 93
12. Free Air Passing Brush Type of Bare Floor Renovator Operated
on Same System with Type C Carpet Renovators 94
13. Horse Power at Hose Cock with Brush Type of Bare Floor
Renovator Operated on Same System with Type C Carpet
Renovators 94
14. Cubic Feet of Free Air Passing the Felt-Covered Floor
Renovator Operated on Same System with Type A Renovators 96
15. Horse Power Required at Hose Cock to Operate Felt-Covered
Floor Renovators Operated on Same System with Type A
Renovators 96
16. Vacuum at Hose Cock with 2 in. Vacuum at Type A Renovator 97
17. Air Quantities when Bristle Bare Floor Renovators are Used in
Conjunction with Type A Carpet Renovators at 2 in. Mercury 98
18. Pipe Sizes Required, as Determined by Air Passing Renovators 109
19. Friction Loss in Pipe Lines, with Carpet Renovators in Use
Exclusively 109
20. Pressure Losses from Inlet to Separator in System for Cleaning
Railroad Cars 121
ILLUSTRATIONS.
FIG. PAGE.
1. Early Type of Mechanical Cleaning Nozzle Using Compressed Air 6
2. Another Type of Compressed Air Cleaning Nozzle, Supplemented
with Vacuum Pipe 8
3. Separators Used With Combined Compressed Air and Vacuum
Machines 9
4. Piston Type of Vacuum Pump, Mounted Tandem With Air
Compressor 9
5. Mr. Kenney’s First Renovators Vacuum Alone Being Used as
Cleaning Agent 10
6. Air Compressors Arranged for Operation as Vacuum Pumps 11
7. Separators Installed by Mr. Kenney in Frick Building 12
8. Vacuum Renovator With Inrush Slot, Introduced by the
Sanitary Devices Manufacturing Company 13
9. First Portable Vacuum Cleaner, Constructed by Dr. William Noe,
of San Francisco, in 1905 16
10. Late Type of Spencer Vacuum Cleaning Machine, Operated by
Multi-Stage Turbine Blowers 17
11. Type A, the Straight Vacuum Tool 26
12. Type B, with Wide Slot and Wide Bearing Surface 26
13. Type C, with Auxiliary Slot, Open to Atmosphere 28
14. Type D, with Two Cleaning Slots 28
15. Type E, with Inrush Slot on Each Side of Vacuum Slot 31
16. Type F, an Exaggerated Form of Type B 31
17. Tests of Three Renovators on Dirty Carpets 35
18. Cleaning Tests of Carpets Filled with Quicksand 39
19. Cleaning Tests Using 1 oz. of Sand Per Square Yard of Carpet 41
20. Three Series of Tests with Kenney Type A Renovators 45
21. Tests by Mr. Reeve, Using Type C Renovator 46
22. Tests by Mr. Reeve, Using Type D Renovator 47
23. Tests Showing Efficiency of Different Types of Renovators at
Different Degrees of Vacuum 50
24. Early Type of Bare Floor Renovator 55
25. Later Type of Bare Floor Renovator 55
26. Another Type of Bare Floor Renovator 56
27. Bare Floor Renovator with Felt Cleaning Surface 57
28. Bare Floor Renovator with Unusual Form of Slot 58
29. Bare Floor Renovator with Hard Felt or Composition Rubber
Strips 58
30. Bare Floor Renovator with Rounded Wearing Surface 59
30a. The Tuec School Tool 62
31. Round Bristle Brush for Carved or Other Relief Work 62
32. Rubber-Tipped Corner Cleaner for Use on Carved or Other
Relief Work 62
33. Early Type of Upholstery Renovator 63
34. Upholstery Renovator with Narrow Slots to Prevent Damage to
Furniture 64
35. Another Type of Upholstery Renovator with Short Slots 65
36. Hand Brush Type of Renovator 65
37. Form of Swivel Joint Connecting Stem to Renovator 72
38. Swivel Joint Arranged to Prevent Dust Lodging Between the
Wearing Surfaces 73
39. Swivel Joint in Use 74
40. Another Use of Swivel Joint, Showing Possibilities of this
Form 75
41. Operator Cleaning Trim of Door with Swivel Joint 76
42. Swivel Joint, with Screwed Union 76
43. Swivel Joint Having Ball Bearings 76
44. Action of Ball-Bearing Swivel Joint 77
45. Illustration of Defects of Plug Cocks 78
46. Bayonet Type of Hose Coupling, Introduced by the American Air
Cleaning Company 82
47. All Rubber Hose Coupling Used by the Spencer Turbine Cleaner
Company 83
48. Chart for Determining Hose Friction 86
49. Effect of Increase of Velocity on the Friction Loss 88
50. Another Test Showing Friction Loss Due to Velocity 89
51. Inlet Cock to Prevent Air Leakage when Not in Use 101
52. Type of Automatic Self-Closing Inlet Cock 102
53. “Smooth Bore” Pipe Coupling 103
54. Joint Made of Standard Pipe Flanges 104
55. Standard Durham Recessed Drainage Fittings Generally Used in
Vacuum Cleaning Installations 105
56. Friction Loss in Pipe Lines 106
57-60. Diagrams Showing Operation of Brush and Carpet Renovators
Under Different Conditions 110
61. Typical Floor Plan of Office Building Illustrating Number of
Sweepers Required 114
62. Plan of Layout for Office Building Showing Best Location (at
d) for Vacuum Producer 118
63. Vacuum Cleaning Layout for a Passenger Car Storage Yard 122
64. Arrangement of Piping Recommended as Best for Passenger Car
Storage Yard 123
65. Good Location for Dust Separator Where Large Areas Are
Served by One Cleaning System 125
66. Location of Separators at Centers of Groups of Risers for
Large Systems 126
67. Early Type of Primary Separator, Used by Vacuum Cleaner
Company 128
68. Primary Separator Used by the Sanitary Devices
Manufacturing Company 128
69. Primary Separator Used by the General Compressed Air and
Vacuum Cleaning Company 129
70. Primary Separator Made by the Blaisdell Engineering Co. 129
71. Secondary Separator Used by the Vacuum Cleaner Company 131
72. Secondary Separator Used by the General Compressed Air
and Vacuum Cleaning Company 131
73. Secondary Separator Used by the Sanitary Devices
Manufacturing Company 132
74. Type of Dry Separator Used as Secondary Separator 134
75. Form of Complete Separator Used by the Vacuum Cleaner
Company 135
76. Complete Separator Brought Out by the Electric Renovator
Manufacturing Company 136
77. Complete Separator Made by the American Radiator Company 137
77a. Interior Construction of Dunn Vacuum Cleaning Machine 140
78. Power Consumption and Efficiency of Air Compressor Used as a
Vacuum Pump 143
79. Modification of Reciprocating Pump Made by the Sanitary
Devices Manufacturing Company 144
80. Power Consumption and Efficiency of Modified Reciprocating
Pump 145
81 and 82. Indicator Cards for Clayton and Modified Pumps 146
83. One of the Pumps Installed in Connection with the Vacuum
Cleaning System in the New York Post Office, the Largest
Reciprocating Pump Used for this Purpose up to the Present 148
84. Interior Arrangement of the Garden City Rotary Pump 149
85. Power Required to Operate Garden City Type of Rotary Pump 150
86. Arrangement of Double-Impeller Root Type Rotary Pump for
Vacuum Cleaning Work 151
87. Rotary Pump Arranged with Double-Throw Switch for Reversing
Pump 152
88. Power Consumption and Efficiency of Root Type of Pump 153
89. The Rotrex Vacuum Pump, Used by the Vacuum Engineering
Company 153
90. Late Type of Centrifugal Exhauster Made by the Spencer
Turbine Cleaner Company 154
91. Power and Efficiency Curves for the Spencer Machine 155
92. Interior Arrangement of Invincible Machine, Manufactured by
the Electric Renovator Manufacturing Company 156
93. Power Consumption, Vacuum and Efficiency of First Types of
Invincible Machine 157
94. Power Consumption, Vacuum and Efficiency of Invincible
Machine After Valve Was Fitted to Discharge 158
95. Four-Sweeper Invincible Plant Installed in the United States
Post Office at Los Angeles, Cal. 159
96. Centrifugal Pump with Single Impeller, Manufactured by The
United Electric Company 161
96a. Test of Centrifugal Pump with Single Impeller 162
97. Steam Aspirator Used by the American Air Cleaning Company 163
98. Steam Consumption of Steam Aspirator 164
99. First Type of Controller Introduced by the Sanitary Devices
Manufacturing Company, known as the “Unloading Valve” 167
100. Test of Controller Connected to Suction of 8-Sweeper Piston
Pump 168
101. Type of Controller for Use on Pumps Without Valves 169
102. Regulator for Motor-Driven Vacuum Pump, Manufactured by the
Cutler-Hammer Manufacturing Company 170
103. Inspirator Type Vacuum Contactor, Used to Control Pilot Motor
of Cutler-Hammer Controller 171
104. Vacometer for Use in Testing Vacuum Cleaning Systems 190
PREFACE.
The contents of this work are compiled from the observations of the
author through the seven years during which he has been engaged in the
preparation of specifications for, and the testing of, complete plants
installed in the buildings under the control of the Treasury Department.
During this time it has become necessary to alter no less than five
times the stock form of specifications for stationary vacuum cleaning
plants which were adopted by the Government, with the intent of
obtaining the widest competition possible with efficient and economical
operation, in order to keep pace with the variation and improvement
in the apparatus manufactured. As each new type of system has come
on the market a personal investigation at the factory, together
with tests, has been made. An exhaustive test of carpet renovators
was also conducted, using one of the Government plants. In addition
the vacometers recommended for use in capacity tests were carefully
calibrated, using the machine at the Department of Agriculture.
The writer wishes to acknowledge the aid received from the various
manufacturers in furnishing illustrations and data on their machines,
to Messrs. Ewing & Ewing and Prof. Sidney A. Reeve for data on tests
made by Prof. Reeve and used in defending the Kenney basic patent.
In analyzing the results of his tests and observations, the writer has
endeavored to put his own conclusions into concrete form for the use
of the consulting engineer and has not entered into the problems to
be encountered in the design and manufacture of the various forms of
apparatus.
CHAPTER I.
HISTORY OF MECHANICAL CLEANING.
=Early Attempts.=--Whenever machinery has been introduced to assist
or replace manual labor, the earlier attempts have been in imitating
the tools formerly used by man. As the earliest mechanically-propelled
carriages were mechanical walking machines, the earliest steamboats
mechanical rowing machines, and the earliest flying machines mechanical
birds, so were the earliest mechanical cleaners in the form of
mechanical brooms.
These mechanical brooms were introduced about 1880 and took the form
of the well-known street sweeper, with a large circular brush mounted
on a four-wheeled cart and rotated by means of gearing driven from the
wheels, the propelling power being the horses which drew the machine.
This machine at once made itself unpopular with the residents of the
streets cleaned on account of its great activity in stirring up dust,
because the streets were swept dry. This trouble was later overcome to
a considerable extent by sprinkling the streets before sweeping, but
only at a sacrifice in efficiency of cleaning, especially where such
uneven surfaces as cobble or medina stone blocks formed the surface
of the roadway. Various attachments were added to reduce this dust
nuisance, but none has apparently been successful, as we see these
machines in their original form in use today.
Almost simultaneously with the introduction of the street sweeper came
its counterpart, the carpet sweeper, with a similar but smaller brush,
enclosed in a wood and metal case, the brush being driven by friction
from the wheels supporting the box and the power for operation being
derived from the person who pushed the machine along the floor.
This machine has not been modified to any great extent during the
thirty odd years of its existence. It is today in practically its
original form, and is doing no better work than when first introduced.
This form of mechanical cleaner occupied the field of household
cleaning for nearly twenty years without a rival, during which time it
won its way into the hearts and hands of many housekeepers in this and
other countries.
=Limitations of the Carpet Sweeper.=--This device, with its light brush
and equally light pressure on the surface cleaned and its limited
capacity for carrying the material picked up, has never been a thorough
cleaner in any sense of the word, and has been and is now used only
to take up that portion of the usual litter and light dust which is
located directly on the surface, and is, therefore, most annoying to
the housekeeper, owing to its being visible to the eye. Because of its
generous proportions, made necessary to accommodate the material picked
up, and its centrally-pivoted handle, made necessary by its mechanical
construction, it is impossible to operate it under low furniture. Like
the lawn mower, it must be in motion in order to operate its revolving
brush, on which its cleaning action is dependent. It is impossible to
make use of same in corners, along walls, or close to heavy furniture,
its use being limited to a literal slicking up of those portions of the
carpet in the most conspicuous portions of the apartment. In spite of
these serious defects it came into, and is still in, nearly universal
use, even in households equipped with the latest approved types of
mechanical cleaners. Its use on bare floors has never been even a
moderate success and in no case has it superseded the broom and dust
pan of our grandmothers.
=Compressed Air Cleaners.=--Compressed air has been in use for many
years in foundries and machine shops, for cleaning castings and
producing certain finishes on metal. With the introduction of modern
electrical machinery it was rapidly adapted to the cleaning of windings
and other inaccessible parts of this machinery. Its first use in
cleaning buildings was undoubtedly in the form of an open jet for
dislodging dust from carvings and relief work, for which purpose it is
very efficient as a remover of the dust from the parts to be cleaned
and also as a distributor of this same dust over the widest possible
area for subsequent removal by other means. It has a draw-back in that
the expansion of air both cools the same and reduces its ability to
retain moisture, resulting in the deposit of moisture on the surfaces
cleaned.
About 1898, attempts to overcome the objections to the open air jet
and to produce a commercially successful compressed air carpet cleaner
were undertaken almost simultaneously by two companies, the American
Air Cleaning Company, of Milwaukee, operating under the Christensen
patents, and the General Compressed Air Cleaning Company, of St. Louis,
operating under the Thurman patents.
The renovator used by the American Air Cleaning Company consisted of a
heavy metal frame, about 18 in. long and 12 in. wide, having mounted
on its longer axis a wedge-like nozzle extending the entire length of
the frame, with a very narrow slit, ¹⁄₆₄ in. wide, extending the entire
length of its lower edge. This nozzle was pivoted and so connected to
the operating handle, by which the renovator was moved over the floor,
that when the renovator was alternately pushed and pulled over the
surface to be cleaned, the slot was always inclined in the direction
in which the renovator was being moved. The top of the renovator was
closed by a canvas bag, smaller at the neck than in its center, which
was supported by a wire hook.
Air was introduced into the nozzle, at a pressure of from 45 to 55
lbs. per square inch, and issued from the slot in a thin sheet which
impinged on the carpet at an angle. The frame was held close to the
carpet by its weight, preventing the escape of the air under its lower
edge. The air striking the carpet at an angle was deflected up into the
bag, inflating same like a miniature balloon. The dust loosened from
the carpet by the impact of the air was carried up into the bag where
it lodged, the air escaping through the fabric of the canvas into the
apartment.
The renovator used by the General Compressed Air Cleaning Company
differed from the above-described renovator in that it contained two
nozzles, with slots inclined at fixed angles to the carpet. A pair of
hand-operated valves were provided in the handle to introduce air into
the nozzle which was inclined in the direction in which the renovator
was moving; otherwise the renovator was identical with that used by
the Milwaukee company.
These renovators were generally supplied with air from a portable unit,
consisting of an air compressor, driven by a gasoline engine mounted
with the necessary gasoline and air storage tanks on a small truck. One
of these machines was in use in Washington last year, but its use at
that time was very limited and it is not to be seen this year.
These trucks were drawn up in front of the building to be cleaned and
a large-size hose, usually 1¹⁄₄ in. in diameter, was carried into the
house and attached to an auxiliary tank from which ¹⁄₂-in. diameter
hose lines were carried to two or more renovators.
A few buildings were equipped with air compressors and pipe lines, with
outlets throughout the building for use with this type of renovator,
among which was the Hotel Astor in New York City.
These renovators, the construction of which is shown diagrammatically
in Fig. 1, required approximately 35 cu. ft. of free air per minute
at a pressure of from 45 to 55 lbs. per square inch and were usually
driven by a 15 H. P. engine.
[Illustration: FIG. 1. EARLY TYPE OF MECHANICAL CLEANING NOZZLE USING
COMPRESSED AIR.]
The renovators were very heavy to carry about, although their operation
with the air pressure under them was not difficult. However, their
operation was complicated, requiring skilled operators. Owing to their
generous proportions it was impossible to clean around furniture,
making its removal from the apartment necessary, and limiting their use
to the cleaning of carpets at the time of general house cleaning. The
cooling effect of the expansion of the air in the nozzle often caused
condensation of moisture on the carpets when the relative humidity
was high. They were also at a disadvantage in that all the heavy dust
collected in the canvas bag had to be carried from the apartment by
hand. Owing to the constant agitation of the dust in the bag by the
entering air currents, much of the finer particles of dust and all
the disease germs liberated by the renovator were blown through the
bag back into the apartment. They were not, therefore, by any means
sanitary devices.
=Vacuum Produced by Compressed Air.=--The General Compressed Air
Cleaning Company also introduced another form of renovator for use with
their compressed air plants. This was composed of an ejector operated
by compressed air, with a short hose attached to a carpet renovator
of the straight narrow-slot type, such as was used later in vacuum
cleaning systems. The outlet from this ejector was connected by another
short hose to a metal box containing a canvas bag, woven backwards and
forwards over metal frames to give a large surface for the passage of
air. The dust picked up by the suction of the ejector was carried with
the air into the box and there separated from the air, which escaped
through the canvas into the apartment.
This form of renovator overcame some of the objections to the former
type in that there was no condensation of moisture on the carpets, and
it was possible to operate the renovator under and around furniture,
and even on portieres and other hangings. However, the apparatus was
rendered inefficient by the resistance of the bag, causing a back
pressure on the injector which greatly reduced its air-drawing capacity.
=Compressed Air Supplemented by Vacuum.=--Shortly after these two
companies began operation, the Sanitary Devices Manufacturing Company,
of San Francisco, introduced a new system of mechanical cleaning under
the Lotz patents. This system used a renovator having a compressed
air nozzle terminating in a narrow slot, similar to the nozzles of the
American and Thurman systems, but differing from them in that the slot
was fixed vertically, pointing downward. This nozzle was surrounded
by an annular chamber having an opening at the bottom of considerable
width. The whole formed a renovator about 14 in. long and not over 2
in. wide at its base. In addition to the compressed air connection to
its nozzle, a second hose, 1 in. in diameter, was connected to the
annular space surrounding the nozzle and led to a vacuum pump by which
the air liberated through the nozzle, together with the dust which
was liberated from the carpet, was carried from the apartment. The
construction of this renovator is shown diagrammatically in Fig. 2.
[Illustration: FIG. 2. ANOTHER TYPE OF COMPRESSED AIR CLEANING NOZZLE,
SUPPLEMENTED WITH VACUUM PIPE.]
As dust-laden air was not suitable to be carried through the pump used
as a vacuum producer, separators had to be provided to remove the dust
from this air before it reached the pump. The separators used consisted
of two cylindrical tanks. The air was introduced into the first tank in
such a way that a whirling motion was imparted to it, thus separating
the heavier particles of dust by centrifugal force. The second tank
contained water which was brought into intimate contact with the air
by means of an atomizer located in the pipe connection between the
two tanks, thus washing the air in a manner somewhat similar to the
familiar air washers used in connection with mechanical ventilating
systems. The air and spray then entered the second tank, above the
water line, where the entrained water separated on the reduction of
velocity and fell back into the water below, to be recirculated through
the atomizer. The air passed on out of the top of the tank to the pump.
An illustration of these separators is shown in Fig. 3.
[Illustration: FIG. 3. SEPARATORS USED WITH COMBINED COMPRESSED AIR AND
VACUUM MACHINES.]
[Illustration: FIG. 4. PISTON TYPE OF VACUUM PUMP, MOUNTED TANDEM WITH
AIR COMPRESSOR.]
=Piston Pump the First Satisfactory Vacuum Producer.=--Various
types of apparatus were tried as vacuum producers, including an air
ejector, such as was used with the Thurman renovator, and found to
be ineffective due to its inability to overcome the back-pressure
necessary to discharge the air through the hose, which was placed on
its outlet. A rotary pump was next tried, but, owing to the selection
of an inefficient type, this was abandoned and, finally, a piston-type
vacuum pump, with very light poppet valves and mounted tandem with the
air compressor, was adapted and remained in use with this system until
straight vacuum was adopted, when the air compression cylinder was
omitted. This pump is illustrated in Fig. 4.
[Illustration: FIG. 5. MR. KENNEY’S FIRST RENOVATOR, VACUUM ALONE BEING
USED AS CLEANING AGENT.]
In this system we see the first sanitary device to be introduced into
the field of mechanical cleaning, as the dust and germ-laden air
were removed entirely from the apartment and purified before being
discharged into the outside atmosphere. The foulness of the water in
the separators clearly showed the amount of impurities removed from the
air.
These machines were mounted on wagons, similar to their forerunners,
and were also installed in many buildings as stationary plants, among
which were the old Palace Hotel and the branch Mint, in San Francisco,
and the old Fifth Avenue Hotel, in New York City.
=Systems Using Vacuum Only.=--In 1902 David T. Kenney, of New York,
installed the first mechanical cleaning system in which vacuum alone
was used as the cleaning agent. Mr. Kenney used a renovator with a slot
about 12 in. long and ³⁄₁₆ in. wide, attached to a metal tube which
served as a handle, and to a ³⁄₄-in. diameter hose and larger pipe line
leading to separators and vacuum pump. Mr. Kenney’s first renovator is
illustrated in Fig. 5.
[Illustration: FIG. 6. AIR COMPRESSORS ARRANGED FOR OPERATION AS VACUUM
PUMPS.]
Mr. Kenney used as vacuum pumps commercial air compressors, the first
of which was installed in the Frick Building in 1902 and is illustrated
in Fig. 6. Later he adapted the Clayton air compressor, with
mechanically-operated induction and poppet eduction valves on larger
sizes, and single mechanically-operated induction and eduction valves
on the smaller sizes.
The separators used by Mr. Kenney differed from those used by the
Sanitary Devices Manufacturing Company in that they contained several
interior partitions, screens, and baffles, and the air was drawn
directly through the body of water in the wet separator. The relative
merits of these types of separators will be discussed in a later
chapter.
[Illustration: FIG. 7. SEPARATORS INSTALLED BY MR. KENNEY IN FRICK
BUILDING.]
The separators installed by Mr. Kenney in the Frick Building, and
which are practically the same as were used by him as long as he
manufactured vacuum cleaning apparatus, are illustrated in Fig. 7.
After his application had been in the patent office for about six years
he was granted a fundamental patent on a vacuum cleaning system.
=Renovator with Inrush Slot.=--The Sanitary Devices Manufacturing
Company then produced a carpet renovator using vacuum only as a
cleaning agent. This cleaner has a wider cleaning slot than the
cleaners usually furnished by Mr. Kenney, about ⁵⁄₁₆ in. wide, with
a supplemental slot or vacuum breaker opening out of the top of the
renovator and separated from the cleaning slot by a narrow partition
extending nearly to the carpet, as illustrated in Fig. 8. The relative
merits of these types of renovators will be discussed in a later
chapter.
[Illustration: FIG. 8. VACUUM RENOVATOR WITH INRUSH SLOT, INTRODUCED BY
THE SANITARY DEVICES MANUFACTURING CO.]
Shortly after the introduction of vacuum cleaning by Mr. Kenney and
the Sanitary Devices Manufacturing Company, the American Air Cleaning
Company published an interesting little booklet entitled, “Compressed
Air Versus Vacuum,” which set forth in great detail the so-called
advantages of compressed air over vacuum as a medium of mechanical
carpet cleaning, and, apparently, proved that vacuum cleaners were much
less efficient than cleaners operated by compressed air. A year or two
later the American Air Cleaning Company evidently had a change of heart
and began to manufacture these same “inefficient” vacuum cleaners.
Their previous treatise on vacuum cleaning, which apparently was not
copyrighted, was republished by both the Sanitary Devices Manufacturing
Company and by the Vacuum Cleaner Company, which had acquired Mr.
Kenney’s patents, and freely distributed. Thus this little work of the
Milwaukee company, instead of injuring their competitors, was turned
into good advertising for them and required a lot of explanation from
the Milwaukee company.
=Steam Aspirators Used as Vacuum Producers.=--The American Air Cleaning
Company used a steam aspirator as its vacuum producer and, unlike its
predecessor, the air-operated ejector, it made good and has also been
used to a limited extent by the Sanitary Devices Manufacturing Company.
It is now marketed by the Richmond Radiator Company, and its merits
will be discussed in a later chapter. The American Air Cleaner Company
also used as a vacuum producer the single-impeller type of rotary pump,
made by the Garden City Engineering Company, which was also later
adopted, to a limited extent, by the Vacuum Cleaner Company. This will
be discussed further on.
The renovator used by this company was a single-slot type, with ¹⁄₈-in.
by 10-in. cleaning slot. These systems at once became notable on
account of the small size of the vacuum producers used, the low degree
of vacuum carried, and the vigorous campaign of advertising which was
conducted.
Several firms soon began to market vacuum cleaning systems almost
identical with that of Mr. Kenney, among which were the Blaisdell
Machinery Company, The Baldwin Engineering Company, and The General
Compressed Air and Vacuum Machinery Company, the latter being the
original Thurman company.
The Vacuum Cleaner Company then began a series of infringement suits
against nearly every manufacturer of vacuum cleaning systems. In nearly
every case the suit has resulted in the offending company paying
license fees to the Vacuum Cleaner Company, and this concern has now
abandoned the manufacture of vacuum cleaners and has become a licensing
company. At this writing nearly twenty firms are paying license fees
to the Vacuum Cleaner Company and there is one suit now in the courts.
=Piston Pump Used Without Separators.=--A vacuum cleaning system of
somewhat different design was produced by two former employees of the
Vacuum Cleaner Company, Mr. Dunn, the once well-known “Farmer Dunn” of
the weather bureau, afterward salesman for the Vacuum Cleaner Company,
and Mr. Locke, at one time this firm’s engineer. This company was first
known as the Vacuum Cleaning Company, and, shortly afterward, as the
Dunn-Locke Vacuum Cleaning Company. No separators were used with this
system, but the dust-laden air was led from the pipe lines directly
into a chamber on the pump, known as the “saturation chamber,” and
there mingled with a stream of water converting the dust into a thin
mud. The air, water and mud then passed through the pump, the muddy
water was discharged into the sewer, and the air into the atmosphere.
The vacuum producer used was a piston pump without suction valves.
With this system it was possible to handle water in almost unlimited
quantities and with this feature a system of mechanical scrubbing was
attempted for which great claims were made, none of which, however,
were realized in a commercial way.
These gentlemen sold their patents to the E. H. Wheeler Company, which
attempted to market the system in its original form. It was found,
however, that the piston pump was not adapted to the handling of grit
which was picked up by the renovators, and a rotary pump, with single
impeller and a follower was substituted. This system is now marketed by
the Vacuum Engineering Company, of New York, and is known as the Rotrex
system.
Mr. Dunn again entered the field of vacuum cleaning and began marketing
his machine a short time ago with a new form of automatic separator
discharging to sewer.
=First Portable Vacuum Cleaner.=--About 1905, Dr. William Noe, of
San Francisco, constructed the first portable vacuum cleaner. This
machine contained a mechanically-driven rotary brush, similar to the
brushes used in the familiar carpet sweeper, for loosening the dust
from the carpet. This dust was sucked up by a two-stage turbine fan
and discharged into a dust bag, mounted on the handle, similar to the
bags on the compressed air cleaners. The whole machine was mounted on
wheels and provided with a small direct-connected motor. This machine
is illustrated in Fig. 9 and is the original form of the well-known
Invincible renovator manufactured by the Electric Renovator Company, of
Pittsburgh. This company now produces a complete line of stationary and
portable vacuum cleaners, all of which use multi-stage turbines. The
sale of the product of this company, until recently, was controlled by
the United States Radiator Corporation.
[Illustration: FIG. 9. FIRST PORTABLE VACUUM CLEANER, CONSTRUCTED BY
DR. WILLIAM NOE, OF SAN FRANCISCO, IN 1905.]
=First Use of Stationary Multi-Stage Turbine Blowers.=--About 1905
Mr. Ira Spencer, president and engineer of the Organ Power Company,
which manufactured a multi-stage turbine blower for organs, known
as the “Orgoblow,” organized the Spencer Turbine Cleaner Company
and marketed a vacuum cleaning system, using a modification of the
“Orgoblow” as a vacuum producer. These machines were first constructed
with sheet metal casings and had sheet steel fans, with wings riveted
on and mounted on horizontal shafts. The separators were sheet metal
receptacles with screens for catching litter. Light-weight hose, 2 in.
in diameter, was used to connect the renovators to 4-in. sheet metal
pipe lines. A variety of renovators was produced for use with this
system. Carpet renovators having cleaning slots varying from 10 in. by
³⁄₄ in. to 20 in. by ¹⁄₄ in. were used, and a very complete line of
swivel joints for connecting the renovators and the hose to the handles
was developed. This system was operated at 5 in. vacuum, which was much
lower than that used by any other system, 15 in. being standard at that
time, and a much larger volume of air was exhausted under certain
conditions than was possible with any of the then existing systems.
Owing to the large volume of air exhausted and to the large size of
the renovators, hose and pipe lines, larger articles could be picked
up than was possible with any of the existing systems. A great deal of
weight was attached to this condition by the manufacturers, a favorite
stunt being to pick up nails, washers, waste, small pieces of paper and
even pea coal from a floor and finally to pick up a quantity of flour
which had first been carefully arranged for the demonstration.
[Illustration: FIG. 10. LATE TYPE OF SPENCER VACUUM CLEANING MACHINE,
OPERATED BY MULTI-STAGE TURBINE BLOWER.]
This invasion of the vacuum cleaning field was considered by the
established manufacturers as a freak and the apparatus was christened
“the tin machine.” Whenever it was installed in competition with other
forms of cleaning systems, the daily question asked by its competitors
was, “Has the tin machine fallen apart?” However, the tin machine did
not fall apart, but held its own with the other systems, even in its
crude and inefficient state. Finding that the construction he had
adopted was too flimsy and subject to abnormal leakage, Mr. Spencer
developed a new form of machine, using cast-iron casing and welded fan
wheels and adopted standard pipe and fittings. He also brought out a
line of sheet metal tools and on the whole perfected a satisfactory
cleaning system. One of his machines of a later type is illustrated in
Fig. 10.
=Separators Emptying to Sewer by Air Pressure.=--A new form of vacuum
cleaning system was introduced by Mr. Moorhead, of San Francisco, who
used an inrush type of renovator having an inlet for air on each side
of the cleaning slot.
The separator used with this system was a wet separator and contained
a screen cleaned by a rotary brush into which all the dust contained
in the air lodged. The pump used with this system was generally of the
piston type, fitted with a single rotary valve, so connected to the
valve stem that it could be rotated thereon and the machine changed
from a vacuum pump to an air compressor in order that the contents of
the separators might be discharged into the sewer by air pressure when
it was desired to empty same.
This system was marketed by the Sanitary Dust Removal Company, of San
Francisco, and, later, was taken over by the American Rotary Valve
Company, of Chicago, which is now marketing same. It eliminates the
manual handling of the dust at any stage of its removal, a feature
which is made much of by its manufacturers, but one which is likely to
cause some trouble for the sewerage system if care is not exercised.
=Machines Using Root Blowers as Vacuum Producers.=--The use of a Root
type of rotary pump as a vacuum producer was first undertaken by the
Foster and Glidden Engineering Company, of Buffalo, which marketed the
Acme system about 1907, the same company having previously built a
similar system for the removal of grain from steam barges. The other
features of this system did not differ materially from those already on
the market.
Being familiar with the various uses to which this type of vacuum pump
had been adapted, the principal one being the operation of pneumatic
tube systems, the author suggested the use of this type of vacuum
producer about two years previous to its introduction and was advised
by one manufacturer that such a type of pump was not suitable for
vacuum cleaning. The fallacy of this statement will be brought out in
detail in a later chapter.
The type of vacuum producer just described has been adopted in many
makes of vacuum cleaners, including the Hope, Connellsville, Arco, and,
lately, in the American Rotary Valve Company’s smaller systems.
During the past four years a score or more of new stationary vacuum
cleaning systems have been introduced, among which are the Palm, a
modification of the Dunn-Locke system; the Tuec, a turbine cleaner; the
Water Witch, which uses a water-operated turbine as a vacuum producer,
and the Hydraulic, with water-operated ejector. At the same time a
hundred or more portable vacuum cleaners have been marketed. These are
of almost every conceivable type and form and are operated by hand,
electricity, and water power. Among them will be found machines which
are good, bad and indifferent, the efficiency and economy of which will
be discussed in a later chapter.
This nearly universal invasion of the vacuum cleaner field by anybody
and everybody looking for a good selling article, establishes the
fact that the vacuum cleaner is not a fad or fancy, but has become
almost a household necessity and has led large corporations to take
it up as a branch of their business. First, the Sanitary Devices
Manufacturing Company and the Vacuum Cleaner Company, the pioneers in
the field, after a legal battle of years, consolidated with a view
of driving their competitors from the field as infringers of the
patents controlled by the two organizations. The result of this was
the licensing of other companies. In an attempt to control the sale of
their type of apparatus notice was served on all users of other types
of vacuum cleaners that they were liable to prosecution for using
infringing apparatus.
Later, the McCrum-Howell Company, a manufacturer of heating boilers
and radiators, secured control of the products of the American Air
Cleaning Company and the Vacuum Cleaner Company and sold these machines
to the trade for installation by the plumbers and steam fitters. The
McCrum-Howell Company has been succeeded by the Richmond Radiator
Company, which is handling these vacuum cleaning machines.
Shortly afterwards, the United States Radiator Corporation secured
control of the Invincible and the Connellsville systems, and, lastly,
the American Radiator Company secured the Wand system.
Thus we see that vacuum cleaning seems to be virtually in the control
of the manufacturers of heating apparatus, who are also among the
largest corporations in this country and well able to control the
future of this business to their liking.
As to the future of vacuum cleaning the author considers that it is at
present, like the automobile, at the height of its career, and also,
like the automobile, that it is a useful appliance to mankind and that
it has its proper place as a part of the mechanical equipment of our
modern buildings.
As to the type of vacuum cleaner of the future, the author believes
that these appliances will become standardized, just as all other
useful appliances have been, and that the form that it will then take
will be a survival of the fittest. What that form may resemble the
reader may more readily judge when he has completed the reading of this
book.
CHAPTER II.
REQUIREMENTS OF AN IDEAL VACUUM CLEANING SYSTEM.
Before a comparison of the relative merits of any line of appliances,
used for any one purpose, can be intelligently made, one must have
either some form of that apparatus which we consider as a standard for
comparison that we may rate all others as inferior or superior thereto,
or else an ideal of a perfect system must be assumed, and the measures
with which each of the various appliances approaches the requirements
of the ideal will establish their relative merits.
The author has elected to use the latter method in comparing the
various systems of vacuum cleaning, and it is necessary, therefore, to
first determine what are the requirements we shall impose on the ideal
system.
An ideal vacuum cleaning system would be one which, when installed in
any building, will displace all appliances used for dry cleaning in the
semi-annual renovating or house cleaning, the weekly cleaning or Friday
sweeping and the daily supplemental cleaning. If our system be truly
an ideal one, the premises should never become so dirty as to require
any semi-annual cleaning at all, and, if the daily cleaning be anyway
thorough, there need be no weekly cleaning. This latter condition may
be governed by the will of the housekeeper or janitor.
The compressed air cleaners first introduced were intended for use
only at the semi-annual cleaning and they were in reality carpet
renovators, which were assumed as imparting to the carpets all the
beneficial results that could be obtained by taking them up and sending
them to a carpet-cleaning establishment, with the advantage over
this latter method, that the labor of removal and replacement of the
carpets was rendered unnecessary, but with the disadvantage that all
the germ-laden air, used as a means of cleaning the carpets, was blown
back into the apartment, leaving the germs in their former abode.
This disadvantage, however, is partly offset by the fact that while the
majority of the germs in one’s own carpet are blown out at the carpet
cleaners, a mixed company of germs from your neighbors’ and others’
carpets, which may be in the tumbling barrel at the same time with your
own, are returned to you with your carpet.
Neither of these conditions is ideal and we will expect our ideal
cleaner to completely remove from the premises, not only the dust and
dirt, but also the germ-laden air which is used as a means of conveying
this dirt.
For replacing the weekly and the daily cleaning, these earlier
renovators were not suitable, as in order to use same the furniture
must all be removed from the apartment.
To accomplish this daily and weekly cleaning, the ideal vacuum cleaner
must replace the broom and dust pan, and their inseparable companion,
the duster, and must also supersede that time-honored mechanical
cleaner, the carpet sweeper.
The reader will doubtless consider that in making this statement the
author is asking the vacuum cleaner to perform much more than it is
usually called on to do. However, we are now discussing an ideal
system, and the above requirements are not absolutely beyond what can
be accomplished by some of the cleaning systems now on the market.
To accomplish this requirement the ideal cleaner must pick up
everything likely to be found on the floor which cannot be readily
picked up by hand. The character of this material will vary greatly
according to the uses of the apartment cleaned. In residences and
offices, where carpets or rugs are in use, cigar stumps and matches
are usually deposited in cuspidors and small pieces of paper in waste
baskets, consequently there should be nothing but dust to be removed
from a residence and, perhaps, mud and sand from the shoes of the many
visitors, in addition to the dust in an office.
However, there are special conditions likely to be met in many cases;
sewing rooms will be littered with basting threads and scraps of
cloth; department stores, with a great quantity of pins; banking rooms
with bands and large-sized bank pins; all of which increase the
requirements of the ideal system. A cleaner which is perfectly adapted
to one sort of apartment will be entirely unsuited for another, and
the ideal cleaner will be one which can be readily adapted to all
conditions likely to be met in the building in which it is installed.
The ideal cleaner must be able to accomplish the above stated
requirements without the necessity of moving heavy pieces of furniture
out of or about the apartment; that is, it must be capable of being
efficiently operated under beds, tables and chairs, around the legs
of other heavy furniture, behind bookcases, pianos, cabinets, etc.,
over curtains, draperies and hangings, over walls, behind pictures and
over mouldings and carved ornaments, all without injury to any of the
furniture or fittings of the apartment, and with the least expenditure
of energy by the operator.
These conditions should be met with the fewest possible number of
cleaning appliances, none of which should be provided with small
attachments liable to be lost or misplaced, and all parts of the
system, which must necessarily be moved about, either before, after or
during the cleaning operation, should be of minimum weight and bulk,
but of rugged and lasting construction.
The ideal vacuum cleaner should be of such proportions and provided
with ample motive power to clean rapidly and effectively.
For use in an office building the cleaner should be able to thoroughly
clean an average-sized office, including floor, walls, furniture and
fittings in from 10 to 15 minutes, and for residence work, should be
of sufficient capacity to clean an apartment, including floor, walls,
curtains, draperies, pictures and furniture in not exceeding 30 minutes.
The ideal system should be so arranged that any apartment in the
building can be cleaned with the least possible disturbance and without
affecting the use of any other apartment, excepting perhaps, the
corridors or hallways.
In large offices, drafting rooms and similar apartments, it may become
necessary to clean same while they are occupied; therefore, our ideal
system must be practically noiseless in operation and must offer the
least possible obstruction to the proper use of the room by its regular
occupants.
=Necessity and Proper Location of Stationary Parts.=--To be of
sufficient power to do rapid cleaning and in order to remove from
the building all dust and germ-laden air, the cleaning system must
necessarily contain some stationary parts. The motive power can
generally be confined to these stationary parts, and must, in such
cases, be located within the building to be cleaned. Therefore, it
should operate with the minimum of noise and vibration.
Machines located in office or other large buildings, containing
elevators or other complicated apparatus requiring skilled attendance,
which are provided with complicated control and with other attachments,
are not objectionable, and in such cases simplicity should give way to
efficiency, but unnecessary complications should be avoided.
In residences and other small buildings, where the vacuum cleaner is
likely to be the only machinery installed, the system must be one which
requires the minimum attention and must be capable of being started
and stopped by any person of average ability, without the necessity of
going to the point where the machine is located.
The power consumption of the ideal system should be a minimum to
accomplish satisfactory results and should be, as nearly as possible,
directly proportioned to the amount of cleaning being done. This
requirement is most important in hotels, where some cleaning is likely
to be done at all hours, day and night. In other words, vacuum must
be “on tap” and as readily attainable at any point in the building as
your water or electric light. In office buildings, where a schedule of
cleaning hours is fixed, and in residences where cleaning hours are few
and the capacity of the plant is rarely more than could be attended to
by one operator, this requirement is not of as great importance.
Lastly, our ideal system, from the standpoint of the purchaser, must be
of such rugged construction, as will enable it to operate efficiently
for, at least, ten years and its mechanical details such that it will
operate continuously, without expert attention, and that the annual
expense for repairs during the life of the machine will not exceed 5%
of the first cost of the system.
CHAPTER III.
THE CARPET RENOVATOR.
In undertaking the comparison of a number of different makes of any
appliance, in order to determine the good and bad points in each,
where the apparatus is composed of a number of separate and distinct
parts, each having its proper function, which they must perform in
order to make the whole apparatus effective, as in a vacuum cleaning
system, it becomes necessary to isolate temporarily each part and
consider its action, first, as a unit working under the most favorable
conditions, and, second, as a component part of the whole apparatus
in order to determine where the weak points in any system occur and
what modifications are necessary in the various parts of the apparatus
to make some vital part of the whole more effective. It is further
necessary to determine what are the vital parts of the system in order
that the other parts may be accommodated to the effective action of
that part.
=Four Important Parts of Vacuum Cleaning System.=--In analyzing a
vacuum cleaning system it naturally divides itself into four parts,
viz.: the cleaning tool or renovator, the air-conveying system or
hose and pipe lines, the separators or other means of disposal of the
material picked up, and the vacuum producer.
The author considers that the renovator is the most important part of
the system and that the other parts should be made of such proportions
and with such physical characteristics as will produce the proper
conditions at the renovator to permit it to perform its functions in
the most effective manner.
As the vacuum cleaning system must be capable of cleaning surfaces of
a widely variable character many forms of renovators are necessary. Of
the various surfaces cleaned the author considers that carpets and rugs
comprise the most important, as well as the most difficult to clean
effectively, so that the carpet renovator will be considered first.
=The Straight Vacuum Tool.=--Various forms of carpet renovators have
been and are in use by manufacturers of vacuum cleaning systems. The
first type of renovator to be considered is that having a cleaning
slot not over 12 in. long, with its edges parallel throughout its
length, and not over ³⁄₈ in. wide, with a face in contact with the
carpet not over ³⁄₈ in. wide on each side of the slot. This form of
renovator is illustrated in Fig. 11 and is designated by the writer
as Type A. The first of these renovators was introduced by Mr. Kenney
and, as finally adopted by him, was 12¹⁄₂ in. long, with ⁷⁄₈-in. face
and with a cleaning slot 11¹⁄₂ in. long and ⁵⁄₃₂ in. wide. This form
of cleaner was termed the “straight vacuum tool” and is used today by
many manufacturers. Slight modifications in its form and dimensions
were made in some cases, as in the one manufactured by the American
Air Cleaning Company. In the one used in all tests by the writer on
type A renovators, the slot was reduced to 10 in. long and ¹⁄₈ in. wide
and the face of the renovator was slightly rounded at the outer edges,
leaving very little surface in contact with the carpet.
[Illustration: FIG. 11. TYPE A, THE STRAIGHT VACUUM TOOL.]
[Illustration: FIG. 12. TYPE B, WITH WIDE SLOT AND WIDE BEARING
SURFACE.]
A renovator of this type is easily operated over any carpet even when
a considerable degree of vacuum exists within the renovator itself.
It has met with favor when used with the piston type of vacuum pump
without vacuum control, as was the case with the earlier systems.
However, when a very high degree of vacuum occurs within the renovator
it has a tendency to pull the nap from the pile of the carpet.
Soon after the introduction of this form of renovator, some users
of same, particularly in San Francisco, complained that while the
renovator effectively removed the dust from carpets it failed to pick
up matches and other small articles and preliminary or subsequent
cleaning was necessary in order to remove such litter.
To overcome this difficulty Mr. Kenney increased the width of the
cleaning slot to nearly ¹⁄₂ in., with the result that when a high
degree of vacuum existed within the renovator, which often occurred
where no vacuum control was used, it stuck to the carpet, rendering
its operation difficult and, at the same time, doing great damage to
the carpet. Hence, its use with the piston type of vacuum pumps was
abandoned.
Mr. Kenney then modified this wide slot renovator by making the face of
same much wider, thus having more surface in contact with the carpet
on each side of the slot, preventing the renovator from sinking into
the nap of the carpet. This type of renovator is illustrated in Fig.
12 and has been designated as Type B. While not as destructive to the
carpets, when a high degree of vacuum existed under the same, it still
pushed hard and was not as rapid a cleaner as the narrow-lipped Type A
renovator.
=Renovator with Auxiliary Slot Open to Atmosphere.=--The renovator
introduced by the Sanitary Devices Manufacturing Company differed
widely from the former types in that it was provided with an auxiliary
slot, open to the atmosphere through the top of the renovator, which
communicated with the slot open to the vacuum by a space of ¹⁄₃₂-in.
under the partition separating the slots. The cleaning slot was made
⁵⁄₁₆-in. wide and the face of the renovator was made 2-in. wide, which
gave a contact of ¹³⁄₃₂-in. in front of the inrush slot and ²¹⁄₃₂-in.
in the rear of the cleaning slot. This form of renovator is illustrated
in Fig. 13 and is designated as Type C.
The auxiliary slot or vacuum breaker permitted air to enter the
cleaning slot even when the renovator was placed on a surface plate,
and, owing to this feature, a high degree of vacuum never existed
within the renovator. It was always easy to operate and did not damage
the carpet. Owing to the wide slot, articles of considerable size
could be picked up, and there was always an abundance of air passing
through the renovator to produce a velocity in the hose and pipe lines
sufficient to carry any heavy articles picked up.
The vacuum producer, control apparatus and the proportions of the
hose and piping used at that time made the degree of vacuum in the
renovator a function of the quantity of air passing, with wide limits
of variation under existing conditions, and this form of renovator is
practically the only one which will do effective cleaning, including
the picking up of litter, without undue wear on carpets, when used
with a system having the above-stated characteristics. This renovator,
however is not without its faults. Owing to the wide surface in contact
with the carpet, a considerable degree of vacuum is necessary in order
that any air shall enter the renovator under the faces of same and, as
the air entering the inrush slot prevents the formation of such vacuum
within the renovator, very little air enters the renovator between
its face and the carpet. When the renovator is operated on a carpet
having a glue-sized back, no air enters through the carpet, therefore
all air entering the renovator must come through the inrush slot and
under the partition separating same from the cleaning slot. Under these
conditions only one side of the vacuum slot is effective and this
effective side is raised above the surface of the carpet.
[Illustration: FIG. 13. TYPE C, WITH AUXILIARY SLOT, OPEN TO
ATMOSPHERE.]
[Illustration: FIG. 14. TYPE D, WITH TWO CLEANING SLOTS.]
When operated on an ingrain or other loose-fabric carpet, much air
enters through the fabric of the carpet, due to the wide cleaning
and inrush slots, in addition to the quantity of air entering through
the inrush slot, making this renovator, when operating under these
conditions, use an unnecessary amount of air. Apparently, this
renovator has been designed to prevent the formation of any great
degree of vacuum under same and such a design has resulted in a greater
volume of air at a lower vacuum passing through than through renovators
of other types.
This property of the renovator raises the question whether the quantity
of air or the degree of vacuum in the renovator is most essential
for the removal of dirt from carpets. Tests made by Mr. S. A. Reeve,
consulting engineer for the Vacuum Cleaner Company, with this type of
renovator, with the inrush open and repeated with the inrush closed,
disclose the fact that it does more effective cleaning with its inrush
closed, while the volume of air passing is considerably less with
the inrush closed. The degree of vacuum was greater, which tends to
indicate that the vacuum within the renovator is the most important
factor.
An extract from the affidavits of Mr. Reeve in one of the numerous
patent suits will show his explanation of this phenomenon: “If we
examine more closely into the actual process whereby such a sweeper
succeeds in extracting dust from carpets, etc., it will appear that the
actual cleaning is effected at the periphery of the slot in the lower
surface of the sweeper. It is accomplished chiefly by the development
of local changes of air pressure at the lips defining this slot,
incidentally to the movement of the tool over the carpet. These changes
cause the air occupying the interstices between the dust particles
to expand suddenly, thus ‘raising the dust.’ To a lesser degree, the
scouring is effected by highly localized air currents of considerable
velocity, engendered where the tool comes in contact with the carpet.
These air currents pick up the dust which has already been expanded
or raised by pressure change. They will be of higher velocity, and
therefore more effective, the better the contact of the tool with the
carpet. The same is true of the pressure changes.
“All this action depends for its intensity, speed and effectiveness,
not on the vacuum existing at the pump or in the separators, but upon
the vacuum prevailing within the sweeper head itself.”
=Renovator with Two Cleaning Slots.=--Another form of renovator was
introduced by the Blaisdell Machinery Company which contained two
cleaning slots each ³⁄₁₆-in. wide and 12-in. long, separated by a
partition ¹⁄₄-in. wide in contact with the surface of the carpet, as
indicated in Fig. 14 (Type D). While this form of renovator has a
greater area of cleaning slot than Type A, its individual cleaning
slots are no wider; therefore, it cannot pick up anything larger than
can be picked up by Type A. As no air can enter under the partition
it can do no more effective work as a dust remover when operated on a
carpet with a glue-sized back and its only advantage over a cleaner
of Type A is that when operated on a loose-fabric carpet more air can
pass through the fabric into the cleaning slot, thus giving a greater
variation in the quantity of air exhausted when operated on carpets of
different texture, a condition which is undesirable when used with a
system having characteristics previously described.
Tests of this type of renovator, made by Mr. Reeve, are given later in
this chapter.
=Renovator with Inrush Slots on Each Side.=--Another form of renovator,
introduced by Mr. Moorhead, is illustrated in Fig. 15 (Type E). This
is a modification of Type A in that an inrush slot is provided on each
side of the vacuum slot, these inrushes being hinged members which
form the sides of the cleaning slot. This cleaner has the advantage
over Type C renovator in that it can take air from either side, but in
action it takes air from but one side at any time. Its inrush will not
become entirely clogged, but its mechanically-moving parts in contact
with the dust and lint picked up will easily become inoperative and are
as like as not to become caught wide open when the air entering the
cleaner will not come into intimate contact with the carpet. In that
event, its cleaning efficiency will be greatly reduced. The author has
not had an opportunity to make any comparative tests of this form of
renovator.
When Mr. Spencer introduced the centrifugal fan as a vacuum producer,
he also brought out a series of carpet renovators of various forms
and sizes. One had a cleaning slot ³⁄₄-in. wide and 10-in. long,
another a slot 15-in. long, ¹⁄₄-in. wide at its end, increasing to
³⁄₄-in. at the center. Another had a slot 20-in. long and ³⁄₈-in.
wide, and finally he adopted a tool with a cleaning slot 15-in. long
and ¹⁄₂-in. wide throughout its length. This is merely the re-entrance
into the field of the wide-slot tool first used by Mr. Kenney and
its successful operation depends on its use with a vacuum producer
of such characteristics and a hose and pipe line of such proportions
that practically a constant vacuum is maintained within the renovator,
regardless of the quantity of air passing through the tool. The latest
form of this renovator, as used by Mr. Spencer, is illustrated in Fig.
16. At the time that the writer made tests on renovators of this make,
the majority of the tests were made with a renovator having a cleaning
slot 10-in. long and ³⁄₄-in. wide. This renovator is designated as Type
F, while the 15-in. × ¹⁄₄-in. to ³⁄₄-in. slot is designated as Type F¹.
[Illustration: FIG. 15. TYPE E, WITH INRUSH SLOT ON EACH SIDE OF VACUUM
SLOT.]
[Illustration: FIG. 16. TYPE F, AN EXAGGERATED FORM OF TYPE B.]
About seven years ago the Supervising Architect of the United States
Treasury Department gave consideration to the use of a carpet cleaning
test to determine the acceptability of any vacuum cleaning system which
might be installed in any of the buildings under his control. The
author was instructed to make a series of tests of carpet renovators,
with a view of determining: (1) the feasibility of using a carpet
cleaning test to determine the merits of a vacuum cleaning system; (2)
to fix the requirements to be incorporated in a specification where
the acceptance of the system was dependent on a satisfactory carpet
cleaning test, to be made at the building after the completion of the
installation; (3) to determine what requirements, other than a cleaning
test, would be necessary to obtain a first-class cleaning system.
The record of many such tests was shown to the author, shortly before
he began making tests. These purported to have been made by Prof.
Miller at the Massachusetts Institute of Technology, with a pump
furnished by the Sanitary Devices Manufacturing Company, in which the
efficiency of the inrush type of renovator (Type C) and the straight
vacuum renovator (Type A) was compared. The results of these tests, as
given in a brief resumé, which was distributed by the Sanitary Devices
Manufacturing Co., indicated that the Type C renovator was the more
rapid and efficient cleaner.
The author learned that these tests were made by the undergraduate
students as a part of the regular laboratory work, and that later a
series of tests was made as the basis of a thesis by Messrs. Paterson
and Phelps in 1906, using the above-described apparatus. The following
year another series of tests was made by Mr. Stewart R. Miller, as the
basis of an undergraduate thesis, in which the efficiencies of the
piston pump and inrush sweeper of the Sanitary Devices Manufacturing
Co. were compared with those of the steam aspirator and straight vacuum
renovator of the American Air Cleaner Company. A copy of this thesis
was furnished the author by the Sanitary Devices Manufacturing Company
shortly after the completion of the tests made by the author.
The relative efficiency of the two types of renovators reported by
these tests differed widely in each case, an occurrence which is liable
to happen where undergraduate students are engaged in such work. They
were, therefore, considered as of doubtful reliability.
The author could find no record of any tests made by anyone of longer
experience and, indeed, these were the only tests of which he could
find any record.
As the author desired to specify a cleaning test which could be readily
repeated at the building in which the cleaning system was installed,
which building was likely to be located in any part of the United
States, no exhaustive laboratory methods were desired or attempted.
As the building was likely to be located in a city where no other
vacuum cleaning systems were then installed and in a new building in
which no dirty carpets were available, and as it was not desirable
to have the contractor furnish the material for the test, it was
considered necessary to use some material in soiling carpets which
would be readily obtainable anywhere, which could be readily brought
to a standard, and which, when worked into the carpets in a reasonable
length of time, would be as difficult to remove as the dirt found in
the average dirty carpet.
=Tests on Dirty Carpets.=--As no tests of cleaning an actually dirty
carpet were on record, quicksand having been used in the Institute of
Technology tests, it was necessary to first clean some carpets that had
been soiled in actual daily service in order to obtain a standard with
which to compare the results in removing various substances, which it
was intended to try as a substitute for dirt. A carpet which had been
in actual use for a number of years on the floors of the old United
States Mint building, in Philadelphia, and receiving the ordinary
amount of cleaning, was procured. This was a Brussels carpet with a
glue-sized back, containing about 20 sq. yds. It was divided into three
approximately equal parts.
An indicator was attached to the vacuum pump for taking air
measurements, and it was found that there was considerable leakage of
air into the system through the connections to the separators and at
other points, therefore the pump was operated with 22 in. of vacuum in
the separator and a card taken with all outlets closed and the amount
of leakage noted. During the tests this degree of vacuum was always
maintained in the separators and pipe lines and the vacuum in the
renovator was varied throughout the tests by throttling the hose cock.
This manner of making tests gave a practically constant leakage which
was deducted from the quantities shown by the indicator cards taken
with the renovators in operation.
As the writer had already made many tests of the efficiency of various
types of vacuum pumps as air movers under various degrees of vacuum,
and as the capacity of the pump available was far in excess of that
required to operate one renovator, no attempt to obtain the efficiency
of the plant as a unit was made. Instead, the vacuum at the hose cock
was adjusted until the degree obtained was what the writer had found to
be within the limit obtained in practice. The resulting vacuum at the
renovator was then noted.
Each piece of carpet was cleaned during six periods of one minute
each, using a different vacuum at the tool for each piece of carpet.
The carpets were weighed at the beginning of the test and after each
one-minute period. At the conclusion of these tests each carpet was
cleaned until no change of weight occurred after two minutes’ cleaning.
They were then considered as being 100% clean and this standard was
made a basis for computing the percentage of dirt removal. A renovator
of Type C was used in these tests.
Shortly afterward a similar test was made on a dirty carpet of 4.6
sq. yds. area, using a renovator of Type F. This carpet was also a
Brussels, with glue-sized back, which had been in use in the shoe
department of a large department store in Hartford. These carpets
contained approximately 2 oz. of dust per square yard, none of which
was visible on the surface, and they were probably as clean as the
average carpet after being gone over with a carpet sweeper or after a
light application of a broom.
TABLE 1.
CLEANING TESTS OF DIRTY CARPETS.
------------------------------+------------+-----------------+------
Type of Renovator. | A | C | F
------------------------------+------------+-----------------+------
Vacuum in renovator, in. Hg | 2 4¹⁄₂| 1 2¹⁄₂ 4 | 3¹⁄₂
Air exhausted, cu. ft. per min| 16 27 | 24 37 44 | 59
Material removed, per cent. of| | |
total, 1 min. | 50 60 | 37 39 47 | 35
Material removed, per cent. of| | |
total, 2 min. | 72 81 | 52 59 63 | 55
Material removed, per cent. of| | |
total, 3 min. | 85 90 | 59 66 71 | 69
Material removed, per cent. of| | |
total, 4 min. | 90 95 | 61 72 83 | 77
Material removed, per cent. of| | |
total, 5 min. | 93 98 | 66 75 87 | 84
Material removed, per cent. of| | |
total, 6 min. | 95 100 | 67 82 90 | 89
H. P. per ounce dust |0.037 0.147 |0.045 0.116 0.252|0.261
Ounces dust per minute |1.9 2.0 |1.34 1.64 1.8 |1.78
H. P. at renovator |0.07 0.29 |0.06 0.19 0.45 |0.475
------------------------------+------------+-----------------+------
As the sizes of the carpets used in making the tests were not always
the same, allowance has been made for this variation by using, in the
case of Type F renovator, instead of the true time, a calculated time
which allows each renovator the same time for cleaning 1 sq. yd. of
carpet. For instance, in the case of the small carpet cleaned with Type
F renovator, an interval of 60 × 4.6 ÷ 6, or 46 seconds, was taken
as equal to one minute’s cleaning of the carpet with types A and C
renovators. Such interval is stated and plotted as one minute in the
table opposite, which gives the results of cleaning dirty carpets with
the three types of renovators.
=Type A Renovator Most Efficient on Dirty Carpets.=--The results of the
tests of the three types of renovators, each when it was operated with
the highest vacuum under the renovator, are plotted in Fig. 17 in order
that a ready comparison may be made. This curve indicates that Type A
renovator does more effective cleaning in less time than either of the
other two types tested.
[Illustration: FIG. 17. TESTS OF THREE RENOVATORS ON DIRTY CARPETS.]
Referring to the second line of the table, which gives the degree of
vacuum obtained in the renovator during the tests, it will be noted
that the highest vacuum attained with each type of renovator is
practically the same. This degree of vacuum was obtained with the
average vacuum at the hose cock, using 100 ft. of hose in each case,
and corresponds to that obtained in the commercial operation of each
of the renovators with the vacuum producers ordinarily used, which was
15 in. in the case of Type C, 10 in. in case of Type A, and 5 in. in
case of Type F, the hose being the size used by each of the systems as
marketed.
The third line, which shows the cubic feet of free air per minute
passing the renovator, indicates that Type A renovator requires much
less air at the same degree of vacuum than either of the other types to
do better work.
From the readings in these two lines the horse power required at the
renovator, to move the air that passes same is obtained with 100%
efficiency adiabatic compression. The results are tabulated in the
ninth line of the table.
This indicates that Type A renovator does more effective work with
about 50% of the power required by either of the other types of
renovators.
The tenth line gives the rate of cleaning and again shows Type A
renovator to be the most rapid cleaner.
The eleventh line gives the horse power required at the renovator when
in operation, from which it will be seen that effective cleaning cannot
be accomplished with less than ¹⁄₄ H. P. at the renovator.
Attention is called to the great reduction in power in case of Type A
renovator when the vacuum at the tool is reduced from 4¹⁄₂ in. to 2
in. and to the small reduction in the efficiency which results from
this great reduction in power. This is not the case with the Type C
renovator, where there is a considerable reduction in the already low
efficiency with each reduction in the vacuum. This characteristic of
Type A renovator is discussed further on in the chapter on hose.
=Tests of Carpets “Artificially” Soiled.=--Having determined the
efficiency of the various types of renovators when operated on dirty
carpets, the author then attempted to find some substance easily
obtained anywhere which could be used as a substitute for actual dirt,
and which would give approximately equal results with these obtained on
dirty carpets.
A test of this character was made by the author some time previous to
the tests of dirty carpets and was made on a Wilton velvet rug of about
12 sq. yds. area. The material spread on same was ordinary wheat flour,
as used in demonstrations, 3 lbs. of which were placed on the rug and
rubbed in with sticks of wood as well as possible and the rug cleaned
for three minutes, using a Type A renovator attached to the separator
with 50 ft. of 1-in. diameter hose. The results were as follows:
VACUUM AT SEPARATOR, PER CENT. DIRT
INS. MERCURY. REMOVED.
5 95
10 98
15 98
The vacuum at the renovator was not measured at the time of making this
test and its amount is not exactly known, but further tests with this
type of renovator under nearly the same conditions gave the following
results:
VACUUM AT HOSE COCK, VACUUM IN RENOVATOR,
INS. MERCURY. INS. MERCURY.
5 3
10 6¹⁄₂
15 9
and it is probable that the vacuum at the renovator during these tests
was approximately the same.
Comparison of the results of this test, in which 4 sq. yds. of carpet
were cleaned per minute, with those of the tests of dirty carpets, in
which only 1 sq. yd. was cleaned per minute, indicates that wheat flour
is not a suitable substitute for dirt in making a carpet cleaning test.
The author, believing that flour is of sufficient fineness, but not of
sufficient weight, tried Portland cement, which is very heavy and at
the same time exceedingly fine, as a substitute for dirt in soiling
carpets. The same carpet that had been cleaned in Philadelphia was used
and 6¹⁄₂ oz. of cement was worked into the same. It was then cleaned
with a Type C renovator, with a vacuum of 2¹⁄₂ in. hg. at the renovator
and 95% of the cement was removed in two minutes’ cleaning, as against
59% of the dirt in the carpet when received.
Ordinary dirt, taken from some flower pots which had been left dry
for some time, was then tried with the same carpet, using a Type C
renovator and 1 in. hg. With this arrangement, 71¹⁄₂% of the dirt was
removed in two minutes as against 52% of the dirt in the carpet as
received.
This dirt was then mixed with water to a thin mud and spread over the
carpet and the carpet dried before cleaning. Then 11¹⁄₄ oz. of this
material was worked into 6 sq. yds. of carpet and a Type C renovator
removed 100% of this in four minutes’ cleaning, with a vacuum of
2¹⁄₂ in. hg. at the tool as against 72% of the dirt in the carpet as
received.
The author’s ingenuity being about exhausted, he referred to the test
of Mr. Stewart R. Miller in which quicksand which would pass a 50-mesh
to the inch screen was used, a long-napped Brussels carpet being filled
with 5¹⁄₂ oz. per square yard and cleaned with Types A and C renovators.
This test indicated that a nearer approach to the results in cleaning
dirty carpets was possible with this substance than with any which
the author had tried. The author repeated Mr. Miller’s test, using a
Type F renovator, 10-in. × ³⁄₄-in. cleaning slot, and also a Type F¹
renovator, 15-in. × ¹⁄₄-in. to ³⁄₄-in. cleaning slot. In duplicating
these tests the author was associated with Mr. E. L. Wilson, a graduate
of the Institute, who was familiar with the methods used by Mr. Miller.
With his assistance, the conditions of Mr. Miller’s tests were almost
exactly duplicated. The results of Mr. Miller’s and the author’s tests
are given in the table opposite, correction being made in the time of
cleaning proportional to the size of carpets used, to allow the same
time for cleaning 1 sq. yd. of carpet by each renovator.
TABLE 2.
CLEANING TESTS OF CARPETS FILLED WITH 5¹⁄₂ OZ. OF QUICKSAND PER SQUARE
YARD OF CARPET.
--------------------------------------------+----+-----+-----+-----
Type of Renovator. | A | C | F | F¹
--------------------------------------------+----+-----+-----+-----
Vacuum in renovator, in. hg. |4¹⁄₂| 4 |3¹⁄₂ |3¹⁄₂
Air exhausted, cubic feet per minute | 27 | 44 | 59 | 54
Material removed, per cent. of total, 1 min.| 60 | 53 | 66 | 53
Material removed, per cent. of total, 2 min.| 75 | 65 | 83 | 75
Material removed, per cent. of total, 3 min.| 82 | 74 | 94 | 86
Material removed, per cent. of total, 4 min.| 87 | 82 |100 | 94
Material removed, per cent. of total, 5 min.| 92 | 87 | -- |100
Material removed, per cent. of total, 6 min.| 95 | 93 | -- | --
H. P. per ounce sand |0.09|0.138|0.084|0.109
Ounces sand per minute |3.2 |3.1 |5.3 |4.0
--------------------------------------------+----+-----+-----+-----
The results of these tests are shown graphically in Fig. 18. Comparison
of these curves with the curves of cleaning dirty carpets (Fig. 17),
shows a falling off in the efficiency of cleaning by Type A renovator
while there is a gain in the efficiency in cleaning by all of the
other types of renovators, Type C being now nearly as efficient as
Type A, while Types F and F¹ renovators are now more efficient than
Type A. This result must be due either to the increased quantity of
material to be removed, 5¹⁄₂ oz. per square yard in case of the sand
as against 2 oz. per square yard in case of the dirt, or else to the
change in the character of the material removed, the sand having much
sharper surfaces than would be encountered in case of dirt which must
necessarily be ground under the feet before it reaches the carpet, or
to the longer nap of the carpet.
[Illustration: FIG. 18. CLEANING TESTS OF CARPETS FILLED WITH
QUICKSAND.]
In order to determine the effect of the increase in the quantity of
material on the results, the tests were repeated using 1 oz. of sand
per square yard of carpet in each case, omitting the test on Type F¹
renovator.
These tests were made on a glue-sized back, short napped Brussels
carpet, using as much sand as could readily be worked out of sight in
this carpet. The results of tests are given in the following table:
TABLE 3.
CLEANING TESTS USING 1 OUNCE OF SAND PER SQUARE YARD OF CARPET.
----------------------------------+-----------+---------------+-----
Type of Renovator. | A | C | F
----------------------------------+-----------+---------------+-----
Vacuum in renovator, in. hg. | 2 4¹⁄₂ | 1 2¹⁄₂ 4 |3¹⁄₂
Air exhausted, cubic feet per min.| 16 27 |24 37 44 | 59
Material removed, per cent. of | | |
total, 1 min. | 48 54 |45 48 50 | 50
Material removed, per cent. of | | |
total, 2 min. | 70 87 |60 63 65 | 73
Material removed, per cent. of | | |
total, 3 min. | 91 100 |73 75 77 | 87
Material removed, per cent. of | | |
total, 4 min. |100 -- |76 81 88 |100
Material removed, per cent. of | | |
total, 5 min. | -- -- |-- 88 97 | --
Material removed, per cent. of | | |
total, 6 min. | -- -- |-- 92 102 | --
H. P. per ounce sand |0.047 0.143|0.06 0.195 0.44|0.223
Ounces sand per minute |1.5 2.0 | -- 0.92 1.02|2.11
----------------------------------+-----------+---------------+-----
The results of these tests at the higher vacua are shown graphically in
Fig. 19. Comparison of these curves with those obtained when removing
sand from a long napped carpet (Fig. 18), shows:
First, a marked increase in the efficiency of Type A renovator, this
being slightly better than obtained when cleaning a dirty carpet.
Second, practically no change in the efficiency of Type C renovator.
Third, a small decrease in the efficiency of Type F renovator, which
still shows a much higher efficiency than when cleaning dirty carpets.
In order to determine how much, if any, of these changes in the
behavior of the renovators was due to the increase in the quantity of
material to be removed, the horizontal line, representing 1 oz. of sand
remaining in the long-napped carpet, was drawn on Fig. 18 and, using
this as a base line, it will be seen that Type A renovator removes this
remaining material in three minutes, the same time as was required to
remove the same amount from the short-napped carpet. However, the first
4¹⁄₂ oz. of sand have been removed from the long-napped carpet in three
minutes, or at a rate 4¹⁄₂ times as fast as the last 1 oz. was removed.
This indicates that the narrow slot renovator is capable of handling
more material than is likely to be encountered in any dirty carpet and
that the apparent decrease in the efficiency of this renovator is not
due to the increased quantity of material to be removed.
[Illustration: FIG. 19. CLEANING TESTS USING 1 OZ. OF SAND PER SQUARE
YARD OF CARPET.]
It will be noted that the Type C renovator removed the last 1 oz. per
square yard from the long-napped carpet in the same time that was
required by Type A renovator, while it needed nearly twice as long to
remove this amount of material from the short-napped carpet (Fig. 19).
This renovator, however, was slower in removing the first 4¹⁄₂ oz. per
square yard.
Type F renovator removed the last 1 oz. per square yard from the
long-napped carpet in two minutes, while it required twice this time
to remove the same amount from the short-napped carpet. This renovator
also removed the first 4¹⁄₂ oz. per square yard from the long-napped
carpet in two minutes, while it required three minutes for Type A and
3-³⁄₄ minutes for Type C renovators to remove the same quantity. It
is, therefore, evident that sand is removed more rapidly from a long
than from a short-napped carpet when a wide slot renovator is used. The
same time is required to remove small quantities of sand from a long or
short-napped carpet with a narrow slot.
This phenomenon is probably due to the sand being held in the carpets
by the adhesion of its sharp edges to the sides of the nap, this
being more pronounced in the case of the long-napped carpet where
it is easier to work the material out of sight without grinding it
into intimate contact with the pile of the carpet. When the wide-slot
renovator passes over the carpet, the carpet is arched up into the
slot and the upper ends of the nap separated. The longer the nap or
the wider the slot, the greater will be this separation. With the
long-napped carpet this separation will at once release the sand,
while, in case of the short nap, there is less separation and also
more adhesion of the sand to the pile of the carpet, due to the harder
grinding necessary to work the material out of sight. Therefore, the
wider the cleaning slot used, the faster the sand will be removed, as
is evident by comparison of the tests of Types F and F¹ renovators on
the long-napped carpet.
With the narrow slot renovator the arching of the carpet under the
cleaning slot is negligible and no advantage is gained when using this
type of renovator to remove sand from a long-napped carpet. It is also
possible that the nap of the carpet may be longer than the width of the
cleaning slot, in which case the nap will not snap back to a vertical
position when it is under the cleaning slot, but will be pressed down
and will impair the action of the renovator. The author considers that
the width of the slot should always be greater than the length of the
nap of the carpet in order to do effective cleaning.
Shortly after making the above-described tests, the author had occasion
to make somewhat similar tests, using a sand-filled carpet, in an
attempt to try out a proposed carpet cleaning test intended to be used
as a standard for use in specifications for a vacuum cleaning system.
When a Wilton carpet was used, it was found that neither Type A or C
renovator would fulfill the test requirements, which were within the
results obtained in tests already described. Unfortunately a Type F
renovator was not available, but the author is of the opinion that it
would have done better.
The test was then repeated, using a Brussels carpet and the test
requirement was easily met. This discovery led the author to make
further tests of carpets of different makes, filled with sand and
cleaned under the same conditions which yielded far from uniform
or satisfactory results, and the use of a cleaning test, where
artificially-soiled carpets are used, was abandoned.
The author is of the opinion that no substance artificially applied to
a carpet, other than regular sweepings, will give anything like the
same results as will be obtained in actual cleaning. Sand seems to be
the only substance which can be worked into the carpet that is nearly
as difficult to remove as the actual dirt found in carpets, and, in
many cases, this material gives results that are misleading and unfair
to some types of renovators. No test which uses a carpet artificially
soiled with artificially prepared dirt is considered to be of any value
in determining the relative efficiency of various types of carpet
renovators.
A series of tests was made by Mr. Sidney A. Reeve consulting engineer,
of New York City, in October, 1910, at the works of the Vacuum Cleaner
Company, Plainfield, N. J., in which the conditions were such as would
give much more uniform results than were possible in the tests made by
the author.
In making these tests the renovator was held firmly clamped in any
desired position in a wooden carriage rolling upon a straight wooden
track. The portion of the carriage supporting the sweeper is attached
to the remainder of the carriage by hinges, so that the sweeper is
free to seek its own contact with the carpet. The carriage was given a
reciprocating motion by its attachment to a large bell crank, which in
turn received its motion from the factory shafting. The construction of
the bell crank was such that the driving power could be readily thrown
in and out of gear at any time.
The carpet was stretched tightly upon a platen which was fitted for
movement across the line of motion of the sweeper, along straight
guides suitably attached to the floor. The ends of the carpet were
first wedged tightly in clamps and the clamps wedged apart so as to
stretch the carpet.
The tests consisted in first weighing the carpet, then stretching it
upon the platen, then sprinkling thereon a suitable and known weight of
dirt taken from the separators of the company’s machines, from which
the lint and coarse, fibrous material had been sifted and which was
thoroughly trodden into the fibres of the carpet, whereupon the sweeper
was set in motion for a given number of strokes.
In nearly all cases the tests were repeated upon the same piece of
carpet, with the same charge of dirt, by repeatedly placing the carpet
in the frame and giving it a further and more extended cleaning.
All tests were corroborated by repetition before being admitted to
the records. Every effort was made to have the tests approach the
conditions occurring in actual practice, as nearly as possible, and
still keep them definite and measurable.
The carpet used was a Wilton, of the standard width of 27 in. and
something over a yard long, and the sweeper was given a stroke of 34
in. at the rate of 40 strokes per minute. The sweepers were attached to
a 6-ft. tubular handle, ¹⁵⁄₁₆-in. inside diameter, and connected to the
separator by 50 ft. of 1-in. diameter hose.
Before making any tests, the piston pump used in the experiments was
calibrated by pumping through a rotary meter and the amount of air
moved per revolution for each degree of vacuum from open inlet to
closed system was carefully determined. In making the tests of various
renovators, each renovator was allowed to pass the same amount of air
as the others tested in comparison therewith and the vacuum at the
renovator and at the separator was allowed to be what was necessary
to pass this known amount of air through the renovators. This method
is widely different from that used by the author where the degree of
vacuum at the renovator head was determined and used as a limiting
factor, the quantity of air being allowed to vary as necessary to
produce this vacuum.
The results of three series of tests are given in Fig. 20, which shows
those obtained with Kenney Type A renovators, having a face 12¹⁄₂ in.
× ⁷⁄₈ in. and a cleaning slot 11¹⁄₂ in. × ⁵⁄₃₂ in. Curve A was made
with the angle of the handle such as would give as near as possible
a perfect contact of the sweeper with the carpet. Curve B was made
with the sweeper handle canted 5° below the proper angle. Curve C was
made with the sweeper handle raised approximately 15° above the proper
angle. The ordinates represented the amount of dust in the carpet
in 40ths of a pound, also reduced by the author to ounces, and the
abscissae the number of strokes made by the sweeper.
[Illustration: FIG. 20. THREE SERIES OF TESTS WITH KENNEY TYPE A
RENOVATORS.]
Curves B and C show the loss in efficiency which occurs when the
renovator is canted from its proper position on the carpet. This
falling off in efficiency will necessarily be greater the wider the
face of the renovator, as is shown in further tests by Mr. Reeve, using
a Type C renovator, which tests also show that this renovator gives a
slightly higher efficiency when operated with the inrush slot stopped,
as is shown in Fig. 21.
In this curve the ordinates represent the per cent. of normal dirt, _i.
e._, the amount likely to be found in a dirty carpet, remaining in the
carpet at any stage of the cleaning, and the abscissae the number of
strokes that have been made by the sweeper. Heavy solid lines represent
the results with the inrush open and dotted lines the results with the
inrush stopped. The figures on the curve represent the degree to which
the handle has been varied from the position giving the best results in
cleaning.
[Illustration: FIG. 21. TESTS BY MR. REEVE, USING TYPE C RENOVATOR.]
Fig. 22 shows the results of tests by Mr. Reeve using a renovator of
Type D, having a double cleaning slot, and indicate that this type
of cleaner is not as efficient as Type A and is affected more by the
canting of the handle from the best angle for cleaning.
The above mentioned tests are published through the courtesy of Messrs.
Ewing and Ewing, attorneys for the Vacuum Clean Cleaner Company.
Since the method of making these tests is entirely different from that
used by the author, a comparison of the results, with any assurance
that the same conditions existed in both cases, is impossible. It
occurred to the author that a comparison of the results of the tests by
Mr. Reeve, using a carpet artificially filled with actual dirt taken
from carpets, with the tests made by the author on carpets naturally
soiled, would tend to show if equal results could be obtained by a
vacuum cleaner by artificially soiling a carpet with dirt taken from
another carpet, and in cleaning a carpet naturally soiled.
[Illustration: FIG. 22. TESTS BY MR. REEVE, USING TYPE D RENOVATOR.]
The author has reduced these results to the same units of time per
square yard of carpet cleaned as in the test on the Philadelphia carpet
with the small-sized Type A renovator (11-in. × ¹⁄₂-in. face and 10-in.
× ³⁄₁₆-in. cleaning slot). The carpet used by the author contained 6
sq. yds. and was held in cleaning by a weight at each corner, while the
carpet used by Mr. Reeve was ³⁄₄ yd. wide and cleaned for approximately
one yard of its length, the relative size being 1 to 8. The time of
cleaning was 6 min. in the author’s test which would correspond to
³⁄₄-min. cleaning in Mr. Reeve’s test, or 30 strokes of the sweeper.
The total dust in the carpet in Mr. Reeve’s test was ⁵⁄₄₀ lbs., or 2.66
oz. per square yard, and his test is compared with the author’s test
with the carpet containing 2 oz. per square yard. Calculation of the
per cent. of total dirt removed in each 5 strokes of the sweeper in
Mr. Reeve’s test, and a comparison of the per cent. of dirt removed in
each one minute’s test by the author are given below:
TABLE 4.
COMPARISON OF TESTS MADE BY MR. REEVE AND BY THE AUTHOR.
-----------------------------+-----------------------------
MR. REEVE’S TEST. | AUTHOR’S TEST.
-----------------------------+-----------------------------
Material removed, | Material removed,
Strokes. per cent. of total.|Minutes. per cent. of total.
-----------------------------+-----------------------------
5 62 | 1 60
10 80 | 2 81
15 89 | 3 90
20 94 | 4 95
25 97 | 5 98
30 99 | 6 100
-----------------------------+-----------------------------
The above comparison was made using curve A, Fig. 20, with the sweeper
at its best angle with the floor. The close agreement of the two tests
indicates that a carpet artificially soiled with dirt actually removed
from another carpet by a vacuum cleaner is as difficult to remove
as dirt which has been worked into a carpet by ordinary daily use.
This condition does not result when any other substance is used to
artificially soil the carpet, as will readily be seen by reference to
the tests of carpets filled with sand and other substances which have
been described in this chapter.
A comparative test of three different renovators was recently made by
the author. Renovator No. 1 had a cleaning slot 14 in. long by ³⁄₄
in. wide, the edges of the slot being a segment of a circle having a
¹⁄₈-in. radius. This form of cleaning surface allows very small area of
contact with the surface cleaned and permits the admission of large air
volumes, about 56 cu. ft., with 2-in. vacuum. It is practically a Type
F renovator, similar to that used in the tests at Hartford.
Renovator No. 2 had a cleaning slot 9¹⁄₂ in. long and ¹⁄₄ in. wide, the
face of the renovator being approximately ⁷⁄₈ in. wide and practically
a plain surface, a typical Type B renovator.
Renovator No. 3 had a cleaning slot 7¹⁄₄ in. long and ¹⁄₈ in. wide,
the face of the renovator being ³⁄₈ in. wide and the edges slightly
rounded, a typical Type A renovator.
The carpet used was a Colonial velvet rug with ¹⁄₈-in. nap, closely
woven, containing 6 sq. yds. This rug was filled with 12 oz. of dirt
taken from separators of cleaning machines, from which the lint and
litter had been screened. This was rubbed into the carpet until no dirt
was visible on the surface, the surface being then lightly swept with a
brush and weighed.
In cleaning this carpet the renovator was passed once over the entire
surface at the rate of about 70 ft. per minute. This required six
strokes and 50 seconds for No. 1 cleaner, nine strokes and 77 seconds
for No. 2 cleaner, and 12 strokes and 100 seconds for No. 3 cleaner.
The carpet was then weighed, spread down and gone over three times,
weighed, spread down and gone over four times. This operation was
repeated until the carpet came within ¹⁄₂ oz. of its weight when
received.
Each of the three renovators was operated with a vacuum of 2 in. at the
renovator.
The results of these tests are illustrated by curves 1A, 2A and 3A in
Fig. 23. This shows that to remove 95% of the dirt the renovator had to
be passed over the carpet 20 times for No. 1 renovator, 15 times for
No. 2 renovator and 8 times for No. 3 renovator.
Similar tests were then made with each of the renovators, with a
vacuum of 4.5 in. of mercury at the renovator. The results are shown
by curves 1B, 2B and 3B (Fig. 23) These show that to remove 95% of the
dirt the renovator had to be passed over the carpet 11 times with No. 1
renovator, 6¹⁄₂ times with No. 2, and 4¹⁄₂ times with No. 3.
These tests are all on the same carpet, with the same quantity of the
same dirt and with the renovators moved at the same speed in each case.
The comparison of the results should give a fair indication of the
efficiency of the different types of renovators at different degrees of
vacuum within the renovator and, therefore, form the most conclusive
proof of the statements relative to the efficiency of renovators as
given in this chapter.
All cleaning tests that the author has observed indicate that the
higher the vacuum within the renovator the more rapid and effective
the cleaning, and that the efficiency of the renovator is fully as
high with a small as with a large volume of air passing through the
renovator and with the same degree of vacuum within same. Therefore,
the most effective and economical renovator should be that which gives
the highest vacuum with the least air passing.
[Illustration: FIG. 23. TESTS SHOWING EFFICIENCY OF DIFFERENT TYPES OF
RENOVATORS AT DIFFERENT DEGREES OF VACUUM.]
If the degree of vacuum within the renovator be carried to an
abnormally high degree, there will be a tendency for the renovator to
cling so close to the carpet that its operation will be difficult and
the wear on the carpet rapid. The production of this high vacuum, with
a larger quantity of air exhausted, will result in the expenditure of
power at the renovator in excess of the gain in efficiency and speed of
cleaning.
It is evident that the wider the cleaning slot, the greater will be the
tendency of the renovator to stick to the carpet with a high vacuum
within the same. The author has experienced no difficulty in operating
the 10-in. renovator, with ³⁄₁₆-in. cleaning slot, with a vacuum as
high as 9 in. of mercury, but wider-slot renovators always push hard
when any high degree of vacuum exists within them.
=Effort Necessary to Operate Various Types of Renovators.=--The author
made a series of tests to determine the effort necessary to operate the
various types of renovators under different conditions. In making these
tests the renovator was attached to a spring balance and pulled along
the floor, the pull required to move the renovator being observed by
the reading of the balance. Three types of renovators were used in this
test: Type A, having a cleaning slot ⁵⁄₁₆ in. wide and 12 in. long;
Type C, having a cleaning slot ⁵⁄₁₆ in. wide and 12 in. long, with an
auxiliary inrush slot ¹⁄₄ in-wide and 12 in. long; Type F, having a
cleaning slot ³⁄₄ in. wide and 10 in. long. The results were as follows:
TABLE 5.
EFFORT NECESSARY TO OPERATE CLEANING TOOLS.
--------------------+----------+----------+-------+------------
| |Vacuum at | |
| Type of |Renovator,| Pull, |Air, cu. ft.
Kind of Carpet. |Renovator.| In. Hg. |Pounds.| per min.
--------------------+----------+----------+-------+------------
Brussels, short | A | 8 | 20 | 27
Napped, close back | C | 6¹⁄₂ | 17 | 31
| F | 3¹⁄₂ | 11 | 59
Axminster, long nap | F | 3¹⁄₂ | 14 | 59
Velvet, with glue | A | 8¹⁄₂ | 18 | 28
Sized back | C | 6¹⁄₂ | 17 | 31
Velvet, without glue| A | 3¹⁄₂ | 15 | 40
Sized back | C | 1 | 12 | 45
Linoleum | A | 13 | 23 | 12¹⁄₂
| C | 1 | 10 | 40
--------------------+----------+----------+-------+----------
It may be noted that, when operating on the Brussels and the glue-sized
velvet, the pull required to move all types of renovators bears a
direct ratio to the degree of vacuum under the renovator, and that
the quantity of air exhausted is the same for each renovator on either
carpet, but different for each type of renovator. It is evident that,
in this case, very little air enters the renovator by passing up
through the carpet, and hence the action of the inrush slot on Type
C renovator is noticeable only to a slight degree. When operating on
velvet carpet, without glue-sized back, the inrush slot, in conjunction
with the greater quantity of air coming through the carpet, has caused
the passage of a large quantity of air, while the vacuum maintained
at the renovator is greatly reduced over that which was maintained
under Type A renovator when the same quantity of air was passing. In
this case, nearly all of the air entering Type A renovator came from
the under side of the carpet. The effect on the efficiency of cleaning
with Type C renovator under these conditions can readily be imagined,
by reference to former tests, as being greatly reduced over that of
Type A when passing the same quantity of air. With linoleum, the action
of the inrush slot of the Type C renovator has again greatly reduced
the vacuum under the renovator, although the quantity of air is much
in excess of that passing Type A renovator. The difference in the
behavior of the renovators on different makes of carpet is seen to be
due largely to the difference in the quantity of air which passes up
through the carpet into the renovator.
It is evident that, with the same degree of vacuum within the
renovator, all types are equally easy to push and that, if the vacuum
within the renovator becomes higher than is necessary to produce good
cleaning results, unnecessary effort will be required to operate the
renovator.
=Relative Damage to Carpets with Various Types of Renovators.=--A few
tests have been made by the author to determine the relative damage to
carpets with the various types of renovators in use and it is found
that, when the edges of the renovators are made exceedingly sharp,
considerable nap is pulled out. However, if the edges are made slightly
rounding and not too narrow, no undue wear will occur with any of the
types of renovators described, provided the vacuum in the renovator is
not permitted to become greater than 5 in. of mercury.
The author considers that for best results the vacuum should not be
less than 3¹⁄₂ in. of mercury at the renovator and that at least 2 in.
is necessary to do even fair work, while, to permit easy operation and
prevent undue wear on the carpets, it should not be higher than 5 in.
Before deciding which type of renovator will be most economical to use
in any case the character of the cleaning to be done must be considered.
Of the various types of renovators considered in this chapter, Type C
can be dismissed at once, as it is neither as effective a dust remover
as Types A or F nor will it remove litter any more effectively than
Type F. Tests of Type D renovator do not show as good results as a dust
remover as Type A, nor will it remove litter any more effectively. Type
E renovator is a modification of Type C and is not likely to be any
better.
The selection, therefore, lies between Type A and Type F renovators,
the former being by far the best dust remover, while the latter will
pick up a limited amount of small litter, such as matches, cigar and
cigarette stumps, and small bits of paper. Where large quantities of
these articles are likely to be encountered, it is more important
that the renovator should be capable of picking them up, but,
unfortunately, when these articles are met with, there are also likely
to be much larger articles present that cannot be picked up by any but
a specially-designed renovator, and other means must be employed to
remove them.
In residences, private offices and nearly every place where carpets or
rugs are likely to be used, waste baskets and cuspidors are provided
and the articles mentioned are deposited in them rather than on the
floor. Thus, the renovator will be required to remove dust, cigar ashes
and sand or mud only, all of which can be readily removed with a Type A
renovator with less expenditure of power than with a Type F renovator.
Public places, such as ante-rooms, reception rooms and other offices
to which the general public is admitted in great numbers and which are
sometimes carpeted, are likely to contain articles which can be picked
up by Type F renovator and not by Type A. For cleaning such places, a
Type F renovator is necessary, although it requires considerably more
power, but the author sees no reason why this type of renovator should
be used to the exclusion of Type A, even in buildings containing rooms
of this character. If the building also contains several rooms where
litter will not be encountered, the author would recommend that both
types of renovators be used, each in its proper place, and thereby
cause a considerable saving of power in cleaning rooms where no litter
is encountered.
For residence work there is little need of providing carpet renovators
capable of picking up litter and, also, there will be very little bare
floor cleaning to be done, which requires larger volumes of air. A
smaller capacity exhausting plant, therefore, can be installed, if the
Type A renovator is adopted.
In large office buildings where all cleaning is done after office
hours, where the building is provided with its own power plant, and
where speed of cleaning and ability to clean all apartments with the
fewest tools to be carried by the cleaners is desired, it appears to be
better to use only Type F renovators for all carpet work, as the extra
power required will not be of vital importance.
Summing up the matter, the author believes that both Type A and F
renovators have their uses in their proper places but that Type A
has the widest field of usefulness, yet it need not invade the field
of the other. He also believes that this fact will be realized by
manufacturers in the near future, when the two types of renovators will
work together side by side for the general good of the manufacturers
and the users.
CHAPTER IV.
OTHER RENOVATORS.
The renovator which is next in importance to the carpet renovator is
that used for cleaning bare floors. The earliest form of this renovator
was the oscillating floor type introduced by Mr. Kenney. This was a
modification of the narrow-slot carpet renovator introduced by him. The
body of same was curved and supported on two small wheels or rollers,
with the intention of bringing the cleaning slot close to the surface
cleaned without its touching same, as indicated in Fig. 24.
[Illustration: FIG. 24. EARLY TYPE OF BARE FLOOR RENOVATOR.]
[Illustration: FIG. 25. LATER TYPE OF BARE FLOOR RENOVATOR.]
This form of renovator was found to be impracticable for the reason
that any change in the angle with which the stem or tube connecting
the body of the renovator with the handle in relation to the surface
cleaned tended to make its action ineffective. If the angle were
made less the distance between the cleaning slot and the floor was
increased, allowing the air to enter the cleaning slot without coming
in contact with the surface to be cleaned, or, if the angle were made
greater, it would cause the face of the renovator to strike and damage
the surface of the floor.