important function of the cleaning system.
Renovators: Same as for Class 3.
Hose: 1¹⁄₂ in. or 1-³⁄₄ in.
Separators: One centrifugal, dry, with or without bag, according to
type of exhauster adopted.
Vacuum Producer: Centrifugal fan or two-impeller rotary pump.
Capacity: 70 to 90 cu. ft. of free air per minute for each sweeper of
plant capacity, with a vacuum of from 2 in. to 3 in. mercury.
Size of motor: 1 to 2 H. P. for each sweeper of plant capacity.
Control: With centrifugal fan, none; with pump, Cutler Hammer.
It is interesting to note that to produce the most efficient plant
for all of the four cases named, all of the various types of vacuum
cleaning systems which have come into general use have to be operated
each under its most favorable conditions and the engineer should
select his plant to best fulfill the conditions of the special case
at hand, just as he would select his prime mover for an electric
generating plant according to its size and location. There should be
no more reason why any one of these systems should attempt to fulfill
the requirements of every installation than there would be for a
manufacturer of steam engines to attempt to use the same type of engine
to drive a generator under all conditions. The writer believes that
this condition will soon be realized by all manufacturers of vacuum
cleaning systems and that they will endeavor to install apparatus of
the type best suited to the conditions to be met in each case.
CHAPTER XIII.
TESTS.
Having decided on the type of vacuum cleaning system that is best
suited to the conditions of the particular building in which it is
to be installed, it then becomes necessary to ascertain what are the
tests necessary to determine whether the installation will produce the
desired results.
If the installation is one in which carpet cleaning is important and
the plant is of more than one-sweeper capacity, the exhauster must
be of sufficient capacity to produce a vacuum of not less than 4 in.
mercury at a carpet renovator attached to any inlet on the piping
system, when the plant is operating other renovators of any type
attached to any of the other inlets corresponding to one less than the
total sweeper capacity of the system.
When hose lengths as short as 25 ft. can be used on any or all of the
outlets, it has been demonstrated in Chapter VII that an air removal of
70 cu. ft. of free air per minute for each sweeper of plant capacity is
necessary, no matter what size of hose is used. It was also shown that
where pipe lines are very long and it is possible to always use 100 ft.
of hose, efficient cleaning can be done with less expenditure of power
with an air displacement of 45 cu. ft. of free air for each sweeper of
plant capacity.
Many methods have been recommended for testing a cleaning plant.
Perhaps the earliest was the maintaining of 15 in. of vacuum at the
vacuum producer with carpet renovators each attached to 100 ft. of
hose, equal in number to the sweeper capacity of the plant in operation
on carpets. Another test is to attach 100-ft. lengths of hose to inlets
on the system, with the ends wide open, equal in number to the sweeper
capacity of the plant, and require the pump to maintain a vacuum of 15
in. mercury.
Both of these tests were recommended for use on plants where 1-in.
diameter hose was provided and the results are dependent largely on the
size and length of the piping system. With an average-sized system, the
first test will require an exhaustion of approximately 25 cu. ft. of
free air per renovator per minute if Type A renovators are used. The
second test wall require an exhaustion of approximately 50 cu. ft. of
free air per open hose per minute. Neither of these tests will insure
a plant of sufficient capacity to do effective cleaning where 25-ft.
lengths of 1-in. hose can be used or if larger bore than 1-in. hose be
used.
If these tests are required with bores larger than 1-in. diameter
and the vacuum is maintained the same as before, air exhaustion with
1¹⁄₄-in. open hose will be approximately 70 cu. ft. of free air per
open hose, and with 1¹⁄₂-in. hose, approximately 150 cu. ft. per open
hose, while, if carpet renovators be used, the vacuum at the renovator
would be from 7 to 9 in. of mercury. In either case, the vacuum
required to be maintained at the separators is higher than is necessary
to produce economical cleaning with either 1¹⁄₄-in. or 1¹⁄₂-in. hose.
Tests with carpet renovators attached to 100 ft. hose lines in number
equal to the capacity of the plant, and a vacuum of 4¹⁄₂ in. of mercury
at the renovator will result in an exhaustion below that necessary
to produce efficient cleaning when bare floor renovators and carpet
renovators with shorter hose lines are used, as is likely to occur in
actual practice.
Again, open hose tests require a variable length of hose to be used in
order to obtain the same air quantity with the proper vacuum at the
separator for economical operation.
If 70 cu. ft. of air is desired, as in the case of Class 2 plant
(Chapter XII), the hose lengths should be:
50 ft. 1 in. diameter. 12 in. vacuum at separator.
75 ft. 1¹⁄₄ in. diameter. 9 in. vacuum at separator.
125 ft. 1¹⁄₂ in. diameter. 6 in. vacuum at separator.
Any of these lengths would give satisfactory cleaning with one carpet
renovator in use, together with sufficient bare floor renovators to
equal the capacity of the plant. This is a possible condition in any
plant.
Another method of testing is to measure the actual air passing through
a given length of hose and require sufficient vacuum at the separator
to produce this flow. This method is open to the objection that
variation in the size of the hose will result in considerable variation
in the vacuum at the separator and conditions of hose lengths may be
such that when carpet renovators are attached to the hose, the vacuum
at the renovator will vary according to the resistance offered to the
passage of the air by the friction in the hose. With the small hose,
the friction will be greatest, and the reduction in the quantity of air
passing the renovator from that passing an open hose will result in the
greatest reduction in friction loss through the hose and produce the
highest vacuum at the renovator. This will cause a widely different
vacuum at the renovator with different sizes of hose, each of which
passes the same amount of air with the end of hose open.
What is desired in cleaning operations is a certain degree of vacuum
at the carpet renovator, with the system operated under the same
conditions that will obtain in practical cleaning, and with cleaners of
various types attached to hose ends equal in number to the capacity of
the plant.
The most rational system of testing is one in which the actual
conditions of air quantity and vacuum are measured at the hose ends.
This can be obtained by actually attaching cleaning tools to the hose
ends and measuring the vacuum within the renovator. However, a wide
variation in vacuum will result when the renovator is moved along the
carpet, and this variation will be different with different operators
and different grades of carpet to such an extent as to render it
impossible to actually meet any requirements that may be specified,
unless a considerable variation in vacuum is permitted.
It is also possible for an operator to become so expert in the
manipulation of the renovators as to be able to meet the specification
requirements with a plant which will not give satisfactory results in
actual operation.
The most satisfactory method of testing that has been devised is the
use of an orifice of proper size fixed to the hose end and measure
the vacuum just inside of this orifice. In making such measurements
care must be taken that the tube connecting to the vacuum gauge is not
inserted in such a manner that the air velocity affects the reading
of the vacuum gauge. The shape of orifice must also be carefully
specified, as the rounding of the edges of the opening will greatly
increase the quantity of air passing a given-sized orifice. The
best standard is a sharp-edged orifice in a thin disk which has a
coefficient of ingress of approximately 65%.
[Illustration: FIG. 104. VACOMETER FOR USE IN TESTING VACUUM CLEANING
SYSTEMS.]
A convenient form of testing appliance based on the orifice test is
the vacometer, manufactured by the Spencer Turbine Cleaner Company
and shown in Fig. 104. This device consists of a spherical aluminum
casting, with a 1-in. diameter hole on the equatorial circle, a vacuum
gauge being attached to one polar extremity, the other being attached
to the end of the hose. A ring having a slip fit is placed around the
equatorial circle in which openings varying from ¹⁄₂-in. to ⁷⁄₈-in.
diameter are drilled. By turning this ring any of the orifices may be
made to register with the opening in the sphere. The opening to which
the vacuum gauge is attached is so located that it is not affected by
the entering air current, and its readings are not affected by the
velocity head.
Experiments with this instrument in connection with a Pitot tube show
that a ¹⁄₂-in. diameter orifice is equivalent to a Type A carpet
renovator, a ⁵⁄₈-in. orifice to a Type F renovator and a ⁷⁄₈-in.
orifice to a bare floor renovator.
With instruments of this type equal in number to the capacity of the
plant in sweepers, attached to the ends of the cleaning hose, it is
possible to obtain uniform conditions equal to the average results that
will be obtained in actual practice with renovators attached to the
hose, without the possibility of expert manipulation of the renovators
affecting the results.
The proper orifice to be used in each vacometer during the test will
vary with the character of the service for which the plant is designed,
and the author recommends the following for each of the classes of
plants described in Chapter XII:
Class 1. 2-in. mercury, with ¹⁄₂-in. orifice, maximum length of hose to
be used in actual cleaning.
Class 2. One-half the inlets ¹⁄₂-in. orifice, 4.5 in. mercury at one
orifice attached at end of longest hose desired to use in practice, the
remaining ¹⁄₂-in. outlets on shorter hose lengths. The other half of
inlets to have ⁷⁄₈-in. orifices open at same time, with longest hose on
one-quarter of total inlets and shortest on the balance.
Class 3. All inlets on long hose, one-half with ¹⁄₂-in. orifice,
balance with ⁷⁄₈-in.
Class 4. All inlets to have ⁷⁄₈-in. orifice and 1 in. vacuum at
vacometer, all hose lines maximum length.
CHAPTER XIV.
SPECIFICATIONS.
Before the engineer begins to prepare his specifications for a proposed
vacuum cleaning system, he will naturally consider carefully the
conditions to be met in the particular installation contemplated.
Having considered these conditions, he can readily determine the
type of system that will operate most efficiently and economically
under such conditions. It is, therefore, natural to assume that
the best interests of his clients can be obtained by confining his
specifications to apparatus of the type giving the most efficient
results for the special conditions to be met. However, it is also
necessary to study the apparatus on the market to determine if there is
a sufficient number of manufacturers producing the particular type of
apparatus specified to insure healthy competition and reasonable bids.
It becomes necessary, therefore, to examine the various systems offered
by the manufacturers in order to determine what competition can be
obtained.
Apparatus for Class 1 or Class 2, if confined to the positive
displacement rotary exhausters of the two-impeller type, can be
obtained from at least seven manufacturers. If the centrifugal fan is
included, at least three other manufacturers can be considered and in
either case a healthy competition be had.
If apparatus of Class 3 is desired, it can be obtained from at least
three manufacturers. A few years ago more manufacturers of systems of
this type were in the market. Some of these have dropped out, owing to
the comparatively limited field for this apparatus. However, there are
still enough manufacturers in the field to insure competition.
Apparatus of Class 4 has been especially manufactured by one company.
However, any of the manufacturers of centrifugal fan type of apparatus
can easily meet the specification requirements for apparatus of the
character.
It is, therefore, evident that the specification of apparatus of the
type best suited to any particular installation will not result in lack
of competition, and such a procedure would apparently be justified.
There are installations, such as those for public buildings, where it
may be advisable from an administrative standpoint to allow the widest
competition possible. In such cases the engineer can secure the best
results for his clients by so drawing his specifications as to include
all types of apparatus, fixing carefully the test requirements to be
met and requiring each bidder to state in his proposal the amount of
power required to operate his apparatus under full load, three-quarter
load and half-load conditions, and to base the award of the contract on
an evaluation basis.
To determine what the basis of this evaluation shall be it is first
necessary to ascertain the length of time the plant will be operated
at each of the loads specified and find the annual cost of a unit of
power to operate the plant. Assuming the plant has a life of ten years,
we can charge 10% depreciation, add to this 5% for interest on the
investment and 1% for insurance. We can capitalize the saving in power
at 16% and use this amount as a basis for evaluation.
As an example, assume one bidder guarantees a power consumption of 1
K. W. less at full load, 1.25 K. W. less at three-quarters load and
0.75 K. W. more at half load than a lower bidder. Assume the plant will
operate 500 hrs. per year at full load, 200 hrs. at three-quarters load
and 300 hrs. at half load. The total kilowatt hours saved by the more
economical plant will be:
Full load 500 × 1 = 500
Three-quarter load 200 × 1.25 = 250
---
Total saving 750
One-half load, 300 × 0.75 = 225
---
Net saving (K. W. Hr.) 525
If power costs 5 cents per K. W. Hr. the yearly saving will be $26.25,
which, capitalized at 16%, will equal $164.00. This is the amount which
the owner would be justified in paying for the more economical plant
above the price asked for the cheaper, but less economical, system.
In order to guard against any bidder guaranteeing a lower power
consumption than he can actually show on test, it is necessary to
impose a penalty for failure to meet the guarantee which is in excess
of the increase in price shown to be justified by the evaluation.
The author recommends that this penalty be made not less than 150% of
the increase in price shown by the evaluation.
Actually, the owner will not lose by the less efficient plant any more
than the amount shown by the evaluation if he junks the plant at the
end of ten years. However, it is more than likely that he will either
use it for a longer time or will be able to realize something for
the plant when it is displaced. The increased penalty, therefore, is
justified, and it is absolutely necessary to make this penalty greater
than the increased value to prevent the bidder guaranteeing a power
consumption lower than he can show on test.
The following pages contain sample specifications for apparatus of
each of the four classes of systems described in Chapter XII and a
specification permitting the widest competition, with evaluation and
penalty clauses.
CLASS 1
PLANT FOR RESIDENCE OR SMALL OFFICE BUILDING OF ONE-SWEEPER CAPACITY.
1. _General Description._ The work included in this specification
shall be the installation of a complete vacuum cleaning system for the
removal of dust and dirt from rugs, carpets, floors, stairs, furniture,
shelves, walls and other fixtures and furnishings throughout the
building, and for conveying said dust and dirt to suitable receptacles
located where shown, together with all of the necessary cleaning tools,
hose, piping, separators, exhauster, motor, etc., as hereafter more
fully specified.
2. _Exhauster._ The exhauster in all of its details shall be made of
the best materials suitable for the purpose and shall be of approved
design and construction, and may be either of the positive displacement
(rotary) or of the multi-stage fan type.
3. _Rotary Exhauster._ The rotary displacement exhauster shall be
either of the two-impeller type or of type having single impeller
without sliding vanes revolving without friction contact with case and
with oscillating follower.
4. Exhausters fitted with sliding blade or blades will not be
acceptable.
5. All parts of the exhauster shall be rigid enough to retain their
shape when the machine is working under maximum-load conditions.
6. The impellers must be machined all over and must be of such shape
and size that they will revolve freely and not touch each other, the
follower, or the casing (cylinder) in which they are placed, but
the clearance must be of the least possible amount consistent with
successful operation.
7. The shafts must be of steel with the journals ground to size.
8. The journal boxes must be long and rigidly supported by the
headplates and placed far enough from the headplates to allow the
placing of proper stuffing boxes on the shafts.
9. The shafts of two impeller exhausters must be connected by
wide-faced steel gears, cut from the solid and securely fastened to the
shafts. Follower shaft on single impeller exhauster to be connected
to impeller shaft by crank and connecting rod. The gears shall run in
suitable oil-tight gear boxes that shall be fitted with adequate and
suitable means for lubrication.
10. _Centrifugal Fan Type._ The centrifugal fan exhauster to be so
proportioned and constructed as to handle the volume of air required at
the specified vacuum with the least possible loss. The housing shall
be of cast iron or aluminum, made in sections. The housing must be
air-tight.
11. The fan wheels to be constructed of steel or other metal of high
tensile strength, properly reinforced, and, if cast, must include hub
and arms complete in one piece. If the fan wheels are built up, they
must be strongly riveted to cast-iron, steel or brass hubs or spiders.
12. The fan wheels are to be secured to shaft with a feather and set
screws, or with left-hand screw.
13. The shaft of fan exhauster may be vertical and the wheels so
mounted that their weight will equalize or partly equalize the end
thrust, or the end thrust may be balanced by the magnetic pull of the
armature. Shaft may be horizontal and end thrust taken care of with
ball-bearing thrust rings.
14. The journal boxes for all of the above named types of exhausters
shall be of the design best adapted for the purpose and must be fitted
with first-class approved continuous lubricating devices, either sight
feed, ring oiler, or any other kind best suited for the work or design
of apparatus used.
15. _Cooling._ The rotary type of exhauster must be provided with the
necessary water connections to properly seal and cool the pump. Fan
type of exhauster must be designed to operate continuously without a
rise of temperature over 100° F. above room temperature.
16. _Speed._ Rotary exhausters shall not exceed a peripheral speed of
1,100 ft. per minute at tips of impellers.
17. Centrifugal fans shall not exceed peripheral velocity of 22,000 ft.
per minute when running under specified full-load conditions.
18. _Mounting._ The exhauster, motor and separators shall be mounted
as a unit on suitable cast-iron base plate, either mounted on legs or
resting on the basement floor.
19. _Drive._ The exhauster shall be driven by an electric motor, which
may be direct connected to the exhauster shaft or be operated with an
oak-tanned leather belt, or by cut gearing. Belt and gearing are to be
of ample size and strength for their work and must run without undue
noise or wear. Means shall be provided to take up the slack of the
belt. Furnish and place a suitable metal guard over belt and pulley
wheels that shall prevent oil being splashed outside of the base plate
and prevent clothing being caught.
20. If the exhauster is operated through cut gearing, the gearing must
be inclosed in an oil and dust proof case, which shall be fitted with
means for copious and continuous lubrication of same.
21. _Finish._ The air exhauster and motor and the base plate shall be
finished in a first-class manner, filled, rubbed down and painted at
least one coat at the shop, and after installation shall receive two
more coats, finishing tint to be as directed.
22. _Electric Motor._ Motor to be of such size that when operating
under test conditions it will not be under less than three-fourths nor
more than full-load condition. It is to be of standard make, approved
by the architect.
23. Motor to be wound for .... volts direct current.
24. Armature to be of toothed-core construction, with windings
thoroughly insulated, and securely fastened in place, and must be
balanced both mechanically and electrically.
25. Commutator segments must be of drop-forged or hard-drawn copper
of highest conductivity, well insulated with mica of even thickness
and proper hardness to insure uniform wear, and shall run free from
sparking or flashing at the brushes under all conditions of speed.
It must be free from all defects and have ample bearing surfaces and
radial depth as provision for wear.
26. Brushes to be of carbon, mounted on a common rocker arm for motor,
and to have cross-sectional area of not less than 1 square inch for
each 35 amperes of current.
27. Brush holders to be of a design to prevent chattering, with
individual adjustment in tension for each brush.
28. Bearings to be of an approved self-oiling or ring type.
29. There must be an insulation resistance between motor frame and
field coils, armature windings and brush holders of not less than 1
megohm.
30. Motor must be capable of standing a breakdown test of 1,500 volts
alternating current. Either or both of the foregoing tests to be
applied at the discretion of the architect’s agent at the time of shop
tests.
31. The maximum rise in temperature of the motor at a continuous run
(after installation at building) at full speed and full-rated load for
a period of eight hours must not exceed 50° C. in windings and 55° C.
on commutator above the surrounding atmosphere.
32. Motor to be finished in a first-class manner, filled and rubbed
down and painted two coats at the shop, and after installation to have
two more coats; finishing tints to be as directed by the superintendent
of the building.
33. _Tablet._ Furnish and mount where directed a polished slate tablet
not less than ³⁄₄ in. thick, having mounted thereon one 30-ampere,
250-volt, double-pole knife switch, with enclosed indicating fuses,
and, if displacement exhauster is furnished, one automatic self-starter
having butt contacts, cutting out starting resistance in not less than
two steps, starter to be controlled by the vacuum in separator, and
shall stop motor when vacuum rises 2 in. above that required to meet
test requirements and start motor when vacuum falls to that required
for working.
34. _Electrical Connections._ This contractor shall run feeders from
vacuum cleaner panel in switchboard where shown to the motor panel and
make all electrical connections between panel and motor, etc.
35. All wires are to be run in standard steel conduit, except those
that are so short as to be self-supporting, and these are to be cord
wrapped or otherwise protected. No wire smaller than No. 8 to be used.
36. All material and workmanship to be strictly first class. Electrical
work must show an insulation resistance of at least 1 megohm, and
to be in strict accordance with the latest edition of the “National
Electrical Code.”
37. _Dust Separator._ There shall be one dry separator located where
shown on plans, having a volume not less than 3 cu. ft.
38. The interior arrangement of the separator shall be such that no
part of same will receive the direct impact of the dust. Cloth bags
or metal screens if used in this separator shall be so placed that
nothing but the very lightest of the dust can lodge thereon, and that
same may be easily cleaned without dismantling the separator. It must
be so constructed that it shall intercept not less than 95% of the dust
entering same.
38a. Separator tank shall be constructed with steel shells, with either
cast iron or steel heads, and be fitted with suitable bases or floor
stands for support and proper openings for cleaning same. Separator
shall be fitted with iron-column mercury gauge reading 50% in excess of
operating vacuum.
39. _Pipe Lines._ All pipe lines shall be of the sizes and run as
indicated on drawings.
40. _Pipes._ All pipe conveying air is to be standard black
wrought-iron or mild-steel screw-jointed pipe, and is to be smooth
inside, free from dents, kinks, fins, or burs. Ends of pipe to be
reamed to the full inside diameter and beveled. Bent pipe to be used in
mains where necessary and where shown on plans.
41. Care must be taken in erecting pipe to maintain as nearly as
possible a smooth, uniform bore through all pipe and fittings.
42. _Fittings._ All fittings to be tough gray cast iron, free from
blowholes or other defects; smooth castings in all cases.
43. All fittings on vacuum lines must have inside diameter through body
of same size as pipe bore, and all fins, burs, or rough places must be
removed.
44. Fittings on vacuum lines are to be black or may be galvanized.
45. Where space permits, all tees and elbows must have a radius at
center line of not less than 3 in.
46. Horizontal overhead pipes to be supported with substantial pipe
hangers spaced not more than 10 ft. apart.
47. The hangers must have an approved form of adjustment and the
instructions of the superintendent in regard to securing hangers to
floor construction, etc., above must be carefully followed.
48. Where exposed pipes pass through walls or floors of finished rooms
they must be fitted with cast-iron nickel-plated plates.
49. _Clean-Out Plugs._ Brass screw-jointed clean-out plugs are to be
provided in lines at all turns where indicated on the drawing. The
clean-out plugs to be 2 in. diameter, except in the 1¹⁄₂-in. lines,
where clean-outs are to be same diameter as the lines.
50. _Exhaust Connection._ Exhaust pipe from the exhauster is to be
run up to the basement ceiling and along same into the smoke breeching
beyond damper as directed.
51. _Sweeper Inlets._ The following number of inlets are to be
provided: Subbasement , basement , first story , second
story , attic .
52. The sweeper inlets are to be fitted with hinged covers or caps with
rubber gaskets arranged to be self-closing when hose is removed, and
those in corridors and lobby arranged to be opened with a key.
53. Inlets coming through finished walls or partitions are to be flush
pattern.
54. Inlets on risers run exposed against walls are to be set close up
against bead of fittings.
55. If contractor desires to use other form of connection than above
described which is equally satisfactory, same must be submitted to the
Architect for approval after award of the contract.
56. In this specification the word “renovator” is used to mean that
portion of the tool which is in contact with the surfaces cleaned; the
word “stem,” that portion connecting the renovator and hose; the word
“cleaner” is used to mean a complete cleaning tool.
57. The following cleaning tools are to be furnished:
One carpet renovator, with cleaning slot ¹⁄₄ in. by 12 in. long.
One bare floor renovator, 12 in. long, with curved felt-covered face.
One wall renovator, 12 in. long, with cotton flannel curved face.
One upholstery renovator, with slot ¹⁄₄ in. by 4 in.
One corner cleaner.
One radiator cleaner.
One hat brush.
One long curved stem about 5 ft. long.
One extension tube about 5 ft. long.
58. The renovators for carpets, bare floors and walls to be arranged
with adjustable swivel joint, so that same can be operated at an angle
with stem from 45° for regular use to an angle of about 80° for use
under or back of furniture and other similar places. This movable joint
to be so arranged that lips of cleaning tool will always remain in
contact with surface cleaned, and constructed so that fitted surfaces
are not exposed to dust, and the air currents when deflected to impinge
only upon surfaces which are of heavy metal and where such wear as
occurs will not affect the operation and handling of the tool.
59. All renovators and stems are to be as light as is consistent with
strength and ability to withstand cutting action of dust.
60. The lips of carpet renovators and upholstery cleaner to be of such
proportions and form as will prevent injury to the fabric, and such
widths as will reduce to a minimum the sticking of renovator face to
the material being cleaned.
61. Stems to be not less than 1 in. outside diameter. Air passages in
swivels to be same diameter as inside of stem. Stem for use with floor
renovators shall be curved near upper end to form handle and provided
with swivel to permit hose hanging vertical.
62. Stems to be drawn-steel or brass tubing, not less than No. 21
United States standard gauge thick if steel and not less than No. 16
Brown & Sharpe gauge thick if brass.
63. Carpet renovators to be made preferably of pressed steel, as light
as possible, or may be made of cast iron, brass or aluminum with iron
wearing face.
64. Bare floor renovators shall have renewable elastic wearing face
curved in direction of motion when cleaning.
65. All renovators and brushes must be provided with proper rubber or
other approved buffers to prevent marring the woodwork.
66. Upholstery cleaners are to have inlet slots or openings of such
size and form as to absolutely prevent drawing in loose covering of
furniture.
67. Upholstery and corner cleaners are not to be arranged for use with
stems, but are to have their own handles permanently attached and be
provided with hose couplings.
68. All metal parts of renovators and stems are to be finished, and all
except aluminum parts nickel plated.
69. _Hose._ Furnish 75 ft. cleaning hose in three 25-ft. lengths.
70. The hose to be 1¹⁄₄ in. inside diameter best quality rubber hose,
reinforced in best manner to absolutely prevent collapse at highest
vacuum obtainable with the exhauster furnished and to prevent collapse
if stepped on. Weight of hose to be not over 12 oz. per linear foot.
71. Couplings for hose to be either slip, bayonet-lock or all-rubber
type, with smooth bore of practically same diameter as inside of
hose. The couplings to have least possible projection outside of hose
dimensions and be well rounded, so as not to injure floors, doors,
furniture, etc.
72. Bayonet joints may have packing washer, and slip joints to have
permanent steel pieces on ends of hose and brass slip coupler. All ends
of hose at couplings to have outside ferrules securely fastened in
place, or pure gum ends glued to coupling. Simple conical slip joints
slipped into ends of hose without ferrules will not be acceptable. All
joints must fit together so that they will not be readily pulled apart.
73. _Tests._ All piping to be tested with air pressure equal to 5 in.
mercury before being concealed in walls and other spaces. Mercury must
not fall more than ¹⁄₄ in. in one-half hour.
74. On completion of plant the pump will be operated with all outlets
closed and, under these conditions, there must be an interval of not
less than 10 min. between the stopping and starting of the motor by the
automatic control, if pump system is used. And if fan system be used,
the power required to operate the exhauster must not be more than 65%
that required in capacity test.
75. To test the capacity of the separator, a mixture containing 6 lbs.
of sand, passed through a 50-mesh screen, 3 lbs. of common wheat flour
and 16 lbs. of Portland cement shall be spread over 50 sq. ft. of
floor and picked up with a renovator attached to the end of 50 ft. of
1¹⁄₄-in. hose. The machine shall be stopped and the material removed
from the separator spread on floor and picked up. This procedure shall
be repeated until the material has been handled four times. If the
separator contains a bag, the same must not be disturbed until after
completion of the capacity test, which will be made with the material
in place in separator, after being picked up the fourth time.
After completion of capacity test, the contents of separator shall
be weighed and if same be a partial separator it must contain 95% of
the material picked up. If a displacement machine is used as a vacuum
producer, the separator must prevent the passage of any dust through
separator, which will be determined by holding a dampened cloth over
pump outlet during test of apparatus. Said cloth must not show any dust
lodged thereon at end of test.
76. To test the capacity of the plant a standard vacometer, attached to
the end of 75 ft. of cleaning hose shall show a vacuum of 2 in. mercury
with ¹⁄₂-in. diameter orifice open.
77. _Test of Cleaning Tools._ The plant shall be operated by the
Contractor in the presence of the Architect’s representative, and a
test made of each kind of cleaning tool furnished. The tool shall be
attached to a 50-ft. length of hose attached to an outlet selected by
the Architect’s representative, and under normal working conditions
each tool must satisfactorily perform the work for which it was
designed. Dust and surfaces to be cleaned shall be furnished by the
contractor.
78. _Painting._ After the completion of the specified tests, all
exposed iron work except galvanized iron or tinned work in connection
with this apparatus, not specified to be otherwise finished, shall be
primed with paint suitable for surfaces covered, and then given two
additional coats. Machinery shall be painted as already specified, and
all other work shall be given finishing tints as selected or approved
by the architect. Black iron pipe, etc., shall be given two coats lead
and oil of tint directed.
=Modifications of Specifications when Alternating Current is
Available.=--When alternating current is available, instead of direct,
modify specifications as follows:
23. Motor to be wound for .... volts, .... cycle, .... phase
alternating current.
24. Motor to have rotor of the squirrel cage type.
Omit 25, 26 and 27.
28. To remain as for direct current.
29. There must be an insulation between the starter or primary windings
and the frame of not less than one megohm.
30, 31, and 32. Same as for direct current.
33. _Tablet._ Furnish and mount where directed a polished slate tablet
having mounted thereon a 30 ampere, 250 volt, .... pole knife switch
with enclosed indicating fuses and, if displacement type exhauster is
furnished, an automatic starter of the “across the line” type, operated
by vacuum in the separator which will stop motor when the vacuum in the
separator rises 2 in. above that required to meet test conditions, and
start exhauster when vacuum reaches working range.
CLASS 2
PLANT FOR LARGE OFFICE BUILDING HAVING PIPE LINES OF MODERATE LENGTH.
1. Same as for Class 1.
2. Omit centrifugal fan.
3 to 9. Same as for Class 1.
Omit 10 to 13.
14 and 16. Same as for Class 1.
15. Omit centrifugal fan.
Omit 17 and 18.
18a. _Base Plate, Foundation, etc._ Provide suitable base plate to
rigidly support the exhauster and its motor as a unit, which shall be
large enough to catch all drip of water or oil. Provide a raised margin
and pads for feet of exhauster frame, motor, and anchor bolts, high
enough to prevent any drip from getting into the foundation or on the
floor.
18b. Provide suitable foundation of brick or concrete, to which the
base plate shall be firmly anchored. The foundation shall be built
on top of the cement floor of the basement, which shall be picked to
afford proper bond for the foundation.
18c. Construct the foundation of such a height as to bring the working
parts of the machine at the most convenient level for operating
purposes. Exposed parts of the foundation to be faced with best grade
white enameled brick. If the base plate does not cover the foundation,
the exposed top surface is to be finished with enameled brick, using
bull-nose brick on all edges and corners.
19 to 23. Same as for Class 1.
23a. The guaranteed efficiency of motor shall not be less than 78% at
half load and not less than 84% at full load.
24 to 32. Same as for Class 1.
32a. Motor shall be subject to shop test to determine efficiency,
heating, insulation, etc. Manufacturer’s certified test sheets of motor
giving all readings taken during shop tests, together with calculated
results, must be submitted to the Architect for approval before motor
is shipped from factory.
33. _Rheostat._ Furnish and install where shown, upon a slate panel
hereinafter specified, a starting rheostat of proper size and approved
made, designed for the particular duty it has to perform. It must
have an automatic no-voltage and overload release. All resistance for
rheostat is to be placed on the back of the tablet. Contacts must
project through board to front side. All moving parts must be on front
of board.
33a. _Tablet._ Furnish and place where shown, a slate tablet not less
than ³⁄₄ in. thick, supported by a substantial angle iron frame, so
placed that there will be a space of not less than 4 in. between the
wall and back of resistance. Mount on this tablet one double-pole,
250-volt knife switch, with two 250-volt inclosed fuses and one
starting rheostat, as specified hereinbefore. The connections shall be
on the back of the tablet. The space between the column and the tablet
shall be inclosed with a removable diamond-mesh grill of No. 10 iron
wire in channel frame.
34, 35, 36. Same as for Class 1.
36a. _Automatic Control._ Suitable means shall be provided in
connection with the rotary exhausters that will maintain the vacuum in
the separators within the limit of the machine at point found to be
most desirable, irrespective of the number of sweepers in operation.
36b. Controller shall consist of a suitable means provided in the
exhauster, or as an attachment thereto, which will automatically throw
the exhauster out of action by admitting atmospheric pressure to the
exhauster only, but not to the system whenever the vacuum in the
separators rises above the point considered desirable, and throw the
exhauster into action when the vacuum falls below the established lower
limit.
36c. _Vacuum Breaker._ In addition to the controlling devices above
specified there shall be placed in the suction pipe to the exhauster an
approved positive-acting vacuum breaker having opening equivalent to
the area of 1-in. diameter pipe and set to open at 10 inches vacuum.
(If plant is to be run for long periods without much load, as in a
hotel, omit 36a, b, c, and substitute):
36d. _Automatic Control._ An approved type of controller for
maintaining practically a constant vacuum by varying the speed of the
motor driving exhauster arranged to permit the operation of the motor
continuously at any speed between full speed and stop, so long as there
be no change in vacuum and which will increase speed whenever vacuum
falls and reduce speed whenever vacuum rises, must be provided.
37. _Dust Separator._ There shall be one dry separator located where
shown on plans, having a volume of not less than 3 cu. ft. for each
sweeper of plant capacity.
38. The interior arrangement of the separator shall be such that no
part of same will receive the direct impact of the dust. Cloth bags
or metal screens, if used in this separator, shall be so placed that
nothing but the very lightest of the dust can lodge thereon, and that
same may be easily cleaned without dismantling the separator. It must
be so constructed that it will intercept all of the dust entering same.
38a to 56. Same as for Class 1.
56a. _Tool Cases._ Furnish approved hardwood cabinet-finished cases
for cleaning tools. Each case to be made as light as possible and of
convenient form for carrying by hand and provided with a complete set
of cleaning tools, each securely held in its proper place, and fitted
with lock and key, clamps, and conveniently arranged handles.
57. Each case shall contain the following:
One carpet renovator, with slot ¹⁄₄ in. by 15 in.
One bare floor renovator, 15 in. long, with curved felt-covered face.
One wall brush, with skirted bristles, 12 in. long and ¹⁄₂ in. wide.
One hand brush, with hose connections at end, 8 in. long, 2 in. wide.
One 4-in. round brush for relief work.
One upholstery renovator.
One corner cleaner.
One radiator tool.
One curved stem about 5 ft. long.
One extension tube 5 ft. long.
At least one hat brush with the system.
58 to 64. Same as for Class 1.
64a. All brushes to be of substantial construction, with best quality
bristles set in close rows and as thick as possible, skirted with
rubber, leather, or chamois skin, so that all air entering renovator
will pass over surface being cleaned.
65 to 68. Same as for Class 1.
69. _Hose Racks._ Furnish and properly secure in place, where directed,
.... hose racks in basement, .... each in first and second stories
(.... racks in all). The racks to be constructed of cast iron,
galvanized or enamel finish, and each rack to be suitable for holding
75 ft. of hose of required size.
69a. _Hose._ There must be furnished with each hose rack 75 ft. of
noncollapsible hose in three 25-ft. lengths.
70 to 73. Same as for Class 1.
74. On completion of the plant the pump will be operated with all
outlets closed, and, under this condition, the power consumption must
not be more than 50% of that required under test conditions.
75. _Test of Separators._ At each of ---- points, near ---- outlets
on different risers selected by the architect’s representative, the
contractor shall furnish and spread on the floor, evenly covering an
area of approximately 50 sq. ft. for each outlet, a mixture of 6 lbs.
of dry sharp sand that will pass a 50-mesh screen, 3 lbs. of fine wheat
flour and 6 lbs. of Portland cement.
75b. Fifty feet of hose shall be attached to each of the ---- outlets,
and the surfaces prepared for cleaning shall be cleaned simultaneously
by operators provided by the contractor until all of the sand, flour
and Portland cement has been taken up, when the exhauster shall be
stopped and the dirt removed from the separator and spread on the floor
again, and the operation of cleaning repeated until the mixture has
been handled by the apparatus four times.
The bag contained in the separator must not be disturbed until after
completion of the capacity test, which will be made with material in
place in the separator after being picked up the fourth time. After
completion of the capacity test the contents of separator will be
removed. During test of separators a dampened cloth will be held over
the exhaust from pump. If such cloth indicates dirt passing through the
separator, same will be rejected.
76. To test the capacity of the plant, one hose line 100 ft. long
shall be attached to inlet farthest from the separator with standard
vacometer, with ¹⁄₂-in. opening in end of hose. .... hose lines shall
be attached to other outlets, each with 50 ft. hose and vacometers in
end of hose, .... vacometers having ¹⁄₂-in. opening and .... vacometers
having ⁷⁄₈-in. opening. Under these conditions 4 in. mercury must be
maintained in vacometer at end of 100 ft. of hose.
77 and 78. Same as for Class 1.
=Modifications of Specifications when Alternating Current is
Available.=--When alternating current is available, instead of direct,
modify specifications as follows:
23. Motor to be wound for .... volts, .... cycle, .... phase
alternating current.
23a. Bidders must name efficiency and power factor of motor at one-half
and full load.
24. Motor to have phase-wound rotor with collector rings for insertion
of starting resistance.
Omit 25, 26 and 27.
28. Same as for direct current.
29. There must be an insulation between the starter or primary windings
and the frame of not less than one megohm.
30, 31, 32, 32a. Same as for direct current.
33. _Rheostat._ Furnish and install an approved hand-starting rheostat
for inserting resistance in rotor circuit in starting, of proper size
to insure the starting of motor in not exceeding 15 seconds without
overheating.
33a. Same as for direct current, except that switch must be either
three- or four-pole, according to current available.
Omit 36d with alternating current machine.
CLASS 3
LARGE INSTALLATION WITH UNUSUALLY LONG PIPE LINES.
1. Same as for Class 1.
2. Exhauster shall be of the reciprocating piston type.
3. The piston type of exhauster shall be double acting and so designed
that the cylinder clearance shall be reduced to a minimum, or suitable
device shall be employed to minimize the effect of large clearance.
4. The induction and eduction valves may be either poppet, rotary, or
semi-rotary, and shall operate smoothly and noiselessly.
5. The piston packing shall be of such character as to be practically
air tight under working conditions and constructed so that it will
be set out with its own elasticity without the use of springs of any
sort. If metallic rings are used, they must fill the grooves in which
they are fitted, both in width and depth, and must be concentric; that
is, of the same thickness throughout. The joint in the ring or rings
to be lapped in width but not in thickness, and if more than one ring
is used they are to be placed and doweled in such position in their
respective grooves so that the joints will be at least one-fourth of
the circumference apart.
6. The piston shall have no chamber or space into which air may leak
from either side of the piston. All openings into the body of the
piston must be tightly plugged with cast-iron plugs.
7. The piston rod stuffing box to be of such size and depth that if
soft packing is used it can be kept tight without undue pressure from
the gland. If metallic packing is used, it must be vacuum tight without
undue pressure on the rod. Proper means shall be provided for the
continuous lubrication of the piston rod.
8. The exhauster of the piston type shall be fitted with an approved
cross-head suitably attached to the piston rod; machines having an
extended piston rod for guide purposes will not be acceptable.
Omit 9 to 13.
14. Same as for Class 1.
15. Reciprocating piston exhauster shall be provided with the
necessary devices for the removal of the heat generated by friction
and compression, that shall prevent the temperature of cylinders or
eduction chambers rising more than 100° F. above the surrounding
atmosphere after two hours’ continuous operation under full-load
conditions.
16. _Speed._ Reciprocating exhauster with poppet valves shall operate
at an average piston speed not exceeding 200 ft. per minute, with
rotary valves not exceeding 300 ft. per minute.
Omit 17 and 18.
18a. _Base Plate, Foundation, etc._ Provide suitable base plate to
rigidly support the exhauster and its motor as a unit, which shall be
large enough to catch all drip of water or oil. Provide a raised margin
and pads for feet of exhauster frame, motor, and anchor bolts, high
enough to prevent any drip from getting into the foundation or on the
floor.
18b. Provide suitable foundation of brick or concrete, to which base
plate shall be firmly anchored. The foundation shall be built on top
of the cement floor of the basement, which shall be picked to afford
proper bond for the foundation.
18c. Construct the foundation of such a height as to bring the working
parts of the machine at the most convenient level for operating
purposes. Exposed parts of the foundation to be faced with best grade
white enameled brick. If the base plate does not cover the foundation,
the exposed top surface is to be finished with enameled brick, using
bull-nose brick on all edges and corners.
19 to 23. Same as for Class 1.
23a. The guaranteed efficiency of motor shall not be less than 80% at
half load and not less than 85% at full load.
24 to 32. Same as for Class 1.
32a. Motor shall be subject to shop test to determine efficiency,
heating, insulation, etc. Manufacturers’ certified test sheets of
motor, giving all readings taken during shop test, together with
calculated results, must be submitted to the Architect for approval
before motor is shipped from factory.
33. _Rheostat._ Furnish and install where shown, upon a slate panel
hereinafter specified, a starting rheostat of proper size and approved
make, designed for the particular duty it has to perform. It must
have an automatic no-voltage and overload release. All resistance for
rheostat is to be placed on the back of the tablet. Contacts must
project through board to front side. All moving parts must be on front
of board.
33a. _Tablet._ Furnish and place where shown, a slate tablet, not less
than ³⁄₄ in. thick, supported by a substantial angle bar frame, so
placed that there will be a space of not less than 4 in. between the
wall and back of resistance. Mount on this tablet one double-pole,
250-volt knife switch, with two 250-volt inclosed fuses and one
starting rheostat, as specified hereinbefore. The connections shall be
on the back of the tablet. The space between the column and the tablet
shall be inclosed with a removable diamond-mesh grill of No. 10 iron
wire in channel frame.
34, 35 and 36. Same as for Class 1.
37. _Dust Separators._ There shall be one dry and one wet separator
located where shown on drawings. Each separator shall have a volume of
3 cu. ft. for each renovator of plant capacity.
38. The separator first receiving the dust shall be a dry separator,
the interior arrangement of which shall be such that no part of same
shall receive the direct impact of the dust. No screens or cloth bags
shall be used in this separator and it must be so constructed that it
will intercept 95% of the dust entering same.
38a. The second separator must be a wet separator which may be
contained in the base of the machine or consist of a separate tank.
38b. Wet separators, whether separate from or integral with the base of
the machine, must be provided with an attachment which will positively
mix the air and water, thoroughly break up all bubbles, separate the
water from the air, and prevent any water entering the exhauster
cylinder.
38c. Suitable means must be provided to automatically equalize the
vacuum between wet and dry separators upon the shutting down of the
exhauster.
38d. The separators must be provided with suitable openings for
access to the interior for inspection and cleaning, and the interior
arrangement of the separators must be such that they may be readily
cleaned without dismantling.
38e. All parts of the wet separator tank not constructed of
non-corrosive metal must be thoroughly tinned or galvanized both inside
and outside. The interior of the wet separator formed in base of
exhauster shall be painted with at least two coats of asphalt varnish
or other paint suitable to prevent the corrosion of same.
38f. Separators must be provided with all necessary valves or other
attachments for successful operation, including a sight glass for the
wet separator, through which the interior of the same may be observed,
and an iron-case mercury column reading 50% in excess of operating
vacuum, attached to the dry separator first receiving the dust.
38g. The wet separator shall be properly connected to water supply
where directed and discharge to sewer where shown on plans.
38h. A running trap with clean-out shall be installed in the waste line.
39 to 41. Same as for Class 1.
41a. Waste and water pipe, in connection with wet separator and jacket,
except waste pipe below basement floor, to be standard galvanized
wrought-iron pipe or steel screw-jointed pipe free from burs. Waste
pipe below the basement floor is to be best grade, “extra heavy”
cast-iron pipe, with lead-calked joints.
42 to 45. Same as for Class 1.
45a. Fittings on water lines to be standard galvanized beaded fittings.
45b. Fittings on waste line above basement floor line to be galvanized
recessed screw-jointed drainage fittings and those below basement floor
to be “extra heavy” cast-iron with hub joints.
46 to 50. Same as for Class 1.
50a. The exhaust pipe is to be fitted with an approved first-class
exhaust muffler not less than 12 in. in diameter and 60 in. high,
closely riveted and constructed of galvanized iron not less than
¹⁄₈ in. thick, and in event an exhauster requiring lubrication is
furnished, this muffler is to be arranged so that it will also be an
efficient oil separator. Drip connection to be arranged at bottom of
muffler.
51 to 56. Same as for Class 1.
56a. _Tool Cases._ Furnish .... approved hardwood cabinet-finished
cases for cleaning tools. Each case to be made as light as possible and
of convenient form for carrying by hand and provided with a complete
set of cleaning tools, each securely held in its proper place, and
fitted with lock and key, clamps and conveniently arranged handles.
57. Each case shall contain the following:
One carpet renovator, with slot ¹⁄₄ in. by 12 in.
One bare floor renovator 12 in. long, with curved, felt-covered face.
One wall brush, with skirted bristles, 12 in. long and ¹⁄₂ in. wide.
One hand brush, with hose connection at end, 8 in. long and 2 in. wide.
One 4-in. round brush for relief work.
One upholstery renovator.
One corner cleaner.
One radiator tool.
One curved stem about 5 ft long.
One straight extension stem 5 ft. long.
At least one hat brush with the system.
58 to 64. Same as for Class 1.
64a. All brushes to be of substantial construction, with best quality
bristles set in close rows and as thick as possible, skirted with
rubber, leather, or chamois skin, so that all air entering renovator
will pass over surface being cleaned.
65 to 68. Same as for Class 1.
69. _Hose Racks._ Furnish and properly secure in place where directed,
.... hose racks in basement, .... each in first and second stories
(.... racks in all). The racks to be constructed of cast-iron,
galvanized or enamel finish, and each rack to be suitable for holding
75 ft. of hose of required size.
69a. _Hose._ There must be furnished with each hose rack 75 ft. of
non-collapsible hose in three 25-ft. lengths.
70. Hose to be 1 in. inside diameter of best quality, rubber hose,
reinforced in best manner to absolutely prevent collapse at highest
vacuum obtainable with the exhauster furnished and to prevent collapse
if stepped on. Weight of hose to be not over 12 oz. per linear foot.
71, 72 and 73. Same as for Class 1.
74. On completion of the plant the pump will be operated with all
outlets closed and, under this condition, the power consumption must
not be more than 50% of that required under test conditions.
75. To test the capacity of the plant, .... hose lines each 100 ft.
long will be attached to outlets on the system and each hose fitted
with a standard vacometer. .... vacometers shall have ¹⁄₂-in. opening
and .... vacometers shall have ⁷⁄₈-in. opening. Under these conditions
4 in. vacuum must be maintained at vacometers having ¹⁄₂ in. opening.
75a. _Test of Separators._ At each of ---- points, near ---- outlets
on different risers selected by the architect’s representative, the
contractor shall furnish and spread on the floor, evenly covering an
area of approximately 50 sq. ft. for each outlet, a mixture of 6 lbs.
of dry sharp sand that will pass a 50-mesh screen, 3 lbs. of fine wheat
flour, and 1 lb. of finely pulverized charcoal.
75b. Fifty feet of hose of size required by the system shall be
attached to each of the ---- outlets, and the surface or surfaces
prepared for cleaning shall be cleaned simultaneously by operators
provided by the contractor until all of the sand, flour and charcoal
has been taken up, when the exhauster shall be stopped and the dirt
removed from the dry separator and spread on the floor again, and the
operation of cleaning repeated until the mixture has been handled by
the apparatus four times. If, after thoroughly flushing the system at
completion of above run, any dust or mud is found in the cylinder,
ports, or valve chambers of the displacement exhauster, or if less
than 95% of the dirt removed is found in the dry separator, it shall be
deemed sufficient ground for the rejection of the separators.
76 and 77. Same as for Class 1.
=Modifications of Specifications when Alternating Current is
Available.=--When alternating current is available, instead of direct,
modify specifications as follows:
23. Motor to be wound for .... volts, .... cycle, .... phase
alternating current.
23a. Bidders must name efficiency and power factor of motor at one-half
and full load.
24. Motor to have phase-wound rotor with collector rings for insertion
of starter resistance.
Omit 25, 26 and 27.
29. Same as for Class 1, alternating current.
33. _Rheostat._ Furnish and install an approved hand-starting rheostat
for inserting resistance in rotor circuit in starting, of proper size
to insure the starting of motor in not exceeding 15 seconds without
overheating.
33a. Same as for direct current, except switch must be either three- or
four-pole, according to current available.
CLASS 4
LARGE OR SMALL PLANT WHERE CARPET CLEANING IS OF SECONDARY IMPORTANCE.
1 to 17. Same as for Class 1.
Omit 18.
18a. _Base Plate, Foundation, etc._ Provide suitable base plate to
rigidly support the exhauster and its motor as a unit, which shall be
large enough to catch all drip of water or oil. Provide a raised margin
and pads for feet of exhauster frame, motor, and anchor bolts, high
enough to prevent any drip from getting into the foundation or on the
floor.
18b. Provide suitable foundation of brick or concrete, to which the
base plate shall be firmly anchored. The foundation shall be built
on top of the cement floor of the basement, which shall be picked to
afford proper bond for the foundation.
18c. Construct the foundation of such a height as to bring the working
parts of the machine at the most convenient level for operating
purposes. Exposed parts of the foundation to be faced with best grade
white enameled brick. If the base plate does not cover the foundation,
the exposed top surface is to be finished with enameled brick, using
bull-nose brick on all edges and corners.
19 to 23. Same as for Class 1.
23a. The guaranteed efficiency of motor shall not be less than 78% at
half load and not less than 84% at full load.
24 to 32. Same as for Class 1.
32a. Motor shall be subject to shop test to determine efficiency,
heating, insulation, etc. Manufacturers’ certified test sheets of
motor, giving all readings taken during shop test, together with
calculated results, must be submitted to the Architect for approval
before motor is shipped from factory.
33. _Rheostat._ Furnish and install where shown, upon a slate panel
hereinafter specified, a starting rheostat of proper size and approved
make, designed for the particular duty it has to perform. It must
have an automatic no-voltage and overload release. All resistance for
rheostat is to be placed on the back of the tablet. Contacts must
project through board to front side. All moving parts must be on front
of board.
33a. _Tablet._ Furnish and place where shown, a slate tablet not less
than ³⁄₄ in. thick, supported by a substantial angle iron frame, so
placed that there will be a space of not less than 4 in. between the
wall and back of resistance. Mount on this tablet one double-pole,
250-volt knife switch, with two 250-volt inclosed fuses and one
starting rheostat, as specified hereinbefore. The connections shall be
on the back of the tablet. The space between the column and the tablet
shall be enclosed with a removable diamond-mesh grill of No. 10 wire in
channel frame.
34, 35 and 36. Same as for Class 1.
36a. _Automatic Control._ Suitable means shall be provided in
connection with the rotary exhauster that will maintain the vacuum in
the separators within the limit of the machine at point found to be
most desirable, irrespective of the number of sweepers in operation.
36b. Controller shall consist of a suitable means provided in the
exhauster, or as an attachment thereto, which will automatically throw
the exhauster out of action by admitting atmospheric pressure to the
exhauster only, but not to the system; whenever the vacuum in the
separator rises above the point considered desirable, and throw the
exhauster into action when the vacuum falls below the established lower
limit.
36c. In addition to control, a positive vacuum breaker having an
opening equal to 1 in. diameter pipe net for 6 in. of mercury, must be
provided on separator.
36d. If centrifugal fan is used, no control or vacuum breaker will be
required.
37. Furnish one separator having a cubic contents of 4.5 cu. ft. for
each sweeper of plant capacity.
38 to 56. Same as for Class 1.
56a. _Tool Cases._ Furnish approved hardwood cabinet-finished cases
for cleaning tools. Each case to be made as light as possible and of
convenient form for carrying by hand and provided with a complete set
of cleaning tools, each securely held in its proper place, and fitted
with lock and key, clamps, and conveniently arranged handles.
57. Each case shall contain the following:
One carpet renovator ¹⁄₂ in. by 15 in.
One bare floor renovator, 15 in. long, with curved felt-covered face.
One wall brush, with skirted bristles, 12 in. long and ¹⁄₂ in. wide.
One hand brush, with hose connection at end, 8 in. long and 2 in. wide.
One 4-in. round brush for relief work.
One upholstery renovator.
One corner cleaner.
One radiator tool.
One curved stem about 5 ft. long.
One straight extension stem 5 ft. long.
At least one hat brush with the system.
58 to 68. Same as for Class 1.
69. _Hose Racks._ Furnish and properly secure in place, where
directed, .... hose racks in basement, .... each in first and second
stories (.... racks in all). The racks to be constructed of cast-iron,
galvanized or enamel finish, and each rack to be suitable for holding
75 ft. of hose of required size.
69a. _Hose._ There must be furnished with each hose rack 75 ft. of
non-collapsible hose in three 25-ft. lengths.
70. Hose to be 1¹⁄₂ in. or 1-³⁄₄ in. inside diameter, best quality
rubber hose, reinforced in best manner to absolutely prevent collapse
at highest vacuum obtainable with the exhauster furnished and to
prevent collapse if stepped on. Weight of hose to be not over 12 oz.
per linear foot.
71 to 73. Same as for Class 1.
74. On completion of the plant the pump will be operated with all
outlets closed and, under this condition, the power consumption must
not be more than 50% of that required under test conditions.
75. Same as for Class 1.
76. To test the capacity of the plant, .... hose lines each 75 ft. long
shall be attached to the inlets, each hose to be fitted with standard
vacometer with ⁷⁄₈-in. opening. Under these conditions a vacuum of 1
in. mercury must be maintained in each vacometer.
77 and 78. Same as for Class 1.
CLASS 5
TO GIVE WIDEST COMPETITION.
1. Same as for Class 1.
2. Exhauster to be piston, rotary or centrifugal fan type.
3. The piston type of exhauster shall be double-acting and so designed
that the cylinder clearance shall be reduced to a minimum, or suitable
devices shall be employed to minimize the effect of large clearances.
4. The induction and eduction valves may be either poppet, rotary or
semi-rotary, and shall operate smoothly and noiselessly.
5. The piston packing shall be of such character as to be practically
air tight under working conditions and constructed so that it will be
set out with its own elasticity without the use of springs of any
sort. If metallic rings are used, they must fill the grooves in which
they are fitted, both in width and depth, and must be concentric; that
is, of the same thickness throughout. The joint in the ring or rings
to be lapped in width but not in thickness, and if more than one ring
is used they are to be placed and doweled in such position in their
respective grooves so that the joints will be at least one-fourth of
the circumference apart.
6. The piston shall have no chamber or space into which air may leak
from either side of the piston. All openings into the body of the
piston must be tightly plugged with cast-iron plugs.
7. The piston-rod stuffing box to be of such size and depth that if
soft packing is used it can be kept tight without undue pressure from
the gland. If metallic packing is used, it must be vacuum tight without
undue pressure on the rod. Proper means shall be provided for the
continuous lubrication of the piston rod.
8. The exhauster of the piston type shall be fitted with an approved
cross-head suitably attached to the piston rod; machines having an
extended piston rod for guide purposes will not be acceptable.
Insert paragraphs 3 to 15 from specifications for Class 1.
15a. Reciprocating exhauster shall be provided with the necessary
devices for the removal of the heat generated by friction and
compression, that shall prevent the temperature of cylinders or
eduction chambers rising more than 100° F. above the surrounding
atmosphere after two hours’ continuous operation under full load
conditions.
15b. _Speed._ Reciprocating exhauster with poppet valves shall operate
at an average piston speed not exceeding 200 ft. per minute, with
rotary valves not exceeding 300 ft. per minute.
Insert paragraphs 16 and 17 from specifications for Class 1.
Omit 18.
18a. _Base Plate, Foundation, etc._ Provide suitable base plate to
rigidly support the exhauster and its motor as a unit, which shall be
large enough to catch all drip of water or oil. Provide a raised margin
and pads for feet of exhauster frame, motor, and anchor bolts, high
enough to prevent any drip from getting into the foundation or on the
floor.
18b. Provide suitable foundation of brick or concrete, to which the
base plate shall be firmly anchored. The foundation shall be built
on top of the cement floor of the basement, which shall be picked to
afford proper bond for the foundation.
18c. Construct the foundation of such a height as to bring the working
parts of the machine at the most convenient level for operating
purposes. Exposed parts of the foundation to be faced with best grade
white enameled brick. If the base plate does not cover the foundation,
the exposed top surface is to be finished with enameled brick using
bull-nose brick on all edges and corners.
19 to 23. Same as for Class 1.
23a. The guaranteed efficiency of motor shall not be less than 78% at
half load and not less than 84% at full load.
24 to 32. Same as for Class 1.
32a. Motors shall be subject to shop test to determine efficiency,
heating, insulation, etc. Manufacturers’ certified test sheets of
motor, giving all readings taken during shop test, together with
calculated results, must be submitted to the architect for approval
before motor is shipped from factory.
33. _Rheostat._ Furnish and install where shown, upon a slate panel
hereinafter specified, a starting rheostat of proper size and approved
make, designed for the particular duty it has to perform. It must
have an automatic no-voltage and overload release. All resistance for
rheostats is to be placed on the back of the tablet. Contacts must
project through board to front side. All moving parts must be on front
of board.
33a. _Tablet._ Furnish and place where shown, a slate tablet not less
than ³⁄₄ in. thick, supported by a substantial angle bar frame, so
placed that there will be a space of not less than 4 in. between the
wall and back of resistance. Mount on the tablet one double-pole,
250-volt knife switch, with two 250-volt enclosed fuses and one
starting rheostat, as specified hereinbefore. The connections shall be
on the back of the tablet. The space between the column and the tablet
shall be enclosed with a removable diamond-mesh grill of No. 10 iron
wire in channel frame.
34, 35 and 36. Same as for Class 1.
36a. _Automatic Control._ Suitable means shall be provided in
connection with the reciprocating and rotary exhausters that will
maintain the vacuum in the separators within the limit of the machine
at point found to be most desirable, irrespective of the number of
sweepers in operation.
36b. Controller shall consist of a suitable means provided in the
exhauster, or as an attachment thereto, which will automatically throw
the exhauster out of action by admitting atmospheric pressure to the
exhauster only, but not to the system; or that shall cause suction from
the system to cease whenever the vacuum in the separators rises above
the point considered desirable, and throw the exhauster into action
when the vacuum falls below the established lower limit.
36c. _Vacuum Breaker._ In addition to the controlling devices above
specified, if a reciprocating or rotary exhauster is used, there
shall be placed in the suction pipe to the exhauster an approved
positive-acting vacuum breaker having opening equivalent to the area of
1-in. diameter pipe and set to open at 12 in.
36d. If centrifugal fan is used, no control or vacuum breaker will be
required.
37. _Dust Separators._ There must be provided at least one separator
between the pipe lines and exhauster having a volume of not less than
3 cu. ft. per sweeper of plant capacity. This separator must be so
constructed that no part thereof will receive the direct impact of the
dust. If rotary exhauster is used, this separator must also contain a
bag so placed that only the lightest dust will reach same and must be
arranged to be readily cleaned without dismantling the separator. If a
centrifugal exhauster is used, this apparatus may or may not contain a
bag, and, if piston pump is used, this separator must contain no bags
or screens whatever. If a piston type of exhauster is installed, an
additional separator must be placed between the first separator and the
exhauster. This must be a wet separator and may be contained in the
base of the machine or consist of a separate tank.
Omit 38.
38a. Same as for Class 1.
38b. Wet separators, whether separate from or integral with the base of
the machine, must be provided with an attachment which will positively
mix the air and water, thoroughly break up all bubbles, separate the
water from the air, and prevent any water entering the exhauster
cylinder.
38c. Suitable means must be provided to automatically equalize the
vacuum between wet and dry separators upon the shutting down of the
exhauster.
38d. The separators must be provided with suitable openings for
access to the interior for inspection and cleaning, and the interior
arrangement of the separators must be such that they may be readily
cleaned without dismantling.
38e. All parts of the wet separator tank (if used) not constructed
of non-corrosive metal must be thoroughly tinned or galvanized both
inside and outside. The interior of the wet separator formed in base of
exhauster shall be painted with at least two coats of asphalt varnish
or other paint suitable to prevent the corrosion of same.
38f. Separators must be provided with all necessary valves or other
attachments for successful operation, including a sight glass for the
wet separator (if used), through which the interior of same may be
observed.
38g. The wet separator (if used) shall be properly connected to water
supply where directed and discharge to sewer where shown on plans.
38h. A running trap with clean-out shall be installed in the waste line.
39 to 41. Same as for Class 1.
41a. Waste and water pipe, in connection with wet separator and jacket,
except waste pipe below basement floor, to be standard galvanized
wrought-iron or steel screw-jointed pipe free from burs. Waste pipe
below the basement floor is to be best grade, “extra heavy” cast-iron
pipe, with lead-calked joints.
42 to 45. Same as for Class 1.
45a. Fittings on water lines to be standard galvanized beaded fittings.
45b. Fittings on waste line above basement floor to be galvanized
recessed screw-jointed drainage fittings and those below basement floor
to be “extra heavy” cast-iron with hub joints.
46 to 50. Same as for Class 1.
50a. If reciprocating exhauster is used, the exhaust pipe is to be
fitted with an approved first-class muffler not less than 12 in. in
diameter and 60 in. high, closely riveted and constructed of galvanized
iron not less than ¹⁄₈ in. thick, and in event an exhauster requiring
lubrication is furnished this muffler is to be arranged so that it will
also be an efficient oil separator. Drip connection is to be arranged
at bottom of muffler.
51 to 56. Same as for Class 1.
56a. _Tool Cases._ Furnish ... approved hardwood cabinet-finished cases
for cleaning tools. Each case to be made as light as possible and of
convenient form for carrying by hand and provided with a complete set
of cleaning tools, each securely held in its proper place, and fitted
with lock and key, clamps, and conveniently arranged handles.
57. Each case will contain the following:
One carpet renovator, with slot ¹⁄₄ in. by not less than 12 or more
than 15 in. long.
One bare floor renovator, 15 in. long, with curved felt-covered face.
One wall brush, with skirted bristles, 12 in. long and ¹⁄₂ in. wide.
One hand brush, with hose connection at end, 8 in. long and 2 in. wide.
One 4-in. round brush for relief work.
One upholstery renovator.
One corner cleaner.
One radiator tool.
One curved stem about 5 ft. long.
One straight extension stem 5 ft. long.
At least one hat brush with the system.
58 to 64. Same as for Class 1.
64a. All brushes to be of substantial construction, with best quality
bristles set in close rows and as thick as possible, skirted with
rubber, leather, or chamois skin, so that all air entering renovator
will pass over surface being cleaned.
65 to 68. Same as for Class 1.
69. _Hose Racks._ Furnish and properly secure in place, where directed,
.... hose racks in basement, .... each in first and second stories
(.... racks in all). The racks to be constructed of cast-iron,
galvanized or enamel finish, and each rack to be suitable for holding
75 ft. of hose of required size.
69a. _Hose._ There must be furnished with each hose rack, 75 ft. of
non-collapsible hose in three 25-ft. lengths.
70. Hose shall not be less than 1 in. or more than 1-³⁄₄ in. inside
diameter, best quality rubber hose, reinforced in best manner to
absolutely prevent collapse at highest vacuum obtainable with the
exhauster furnished and to prevent collapse if stepped on. Weight of
hose to be not over 12 oz. per linear foot.
71 to 73. Same as for Class 1.
74. On completion of the plant, the pump will be operated with all
outlets closed and under this condition the power consumption must not
be more than 50% of that required under test conditions.
75. To test the capacity of plant, one hose line 100 ft. long shall be
attached to inlet farthest from the separator, with standard vacometer
with ¹⁄₂-in. opening in end of hose. Hose lines shall be attached to
other outlets, each with 50-ft. hose and vacometer in end of hose, ....
vacometers having ¹⁄₂-in. opening and .... vacometers having ⁷⁄₈-in.
opening. Under these conditions 4 in. mercury must be maintained in
vacometer at end of 100 ft. of hose.
75a. _Test of Separators._ At each of ---- points, near ---- outlets on
different risers selected by the .... representative, the contractor
shall furnish and spread on the floor, evenly covering an area of
approximately 50 sq. ft. for each outlet, a mixture of 6 lbs. of dry
sharp sand that will pass a 50-mesh screen, 3 lbs. of fine wheat flour,
and 1 lb. of finely pulverized charcoal, if wet separator be used, and
6 lbs. of Portland cement, if bag be used.
75b. Fifty feet of hose of size required by the system used shall
be attached to each of the ---- outlets, and the surface or surfaces
prepared for cleaning shall be cleaned simultaneously by operators
provided by the contractor until all of the sand, flour and charcoal
has been taken up, when the exhauster shall be stopped and the dirt
removed from the dry separator and spread on the floor again, and the
operation of cleaning repeated until the mixture has been handled by
the apparatus four times. If, after thoroughly flushing the system
at completion of the above run, any dust or mud is found in the
cylinder, ports, or valve chambers of the displacement exhauster, or
if less than 95% of the dirt removed is found in the dry separator
of the centrifugal exhauster, it shall be deemed sufficient ground
for the rejection of the separators. If bag is used, same must not be
disturbed until after capacity test, which will be made with material
in separator after being picked up the fourth time.
76-77. Same as for Class 1.
78. Evaluation of proposal (for 4-sweeper plant): No proposal will be
considered which contemplates furnishing an exhauster requiring more
power to operate under test conditions than:
Full load, 14 K. W.; three-quarter load, 12.25 K. W.; one-half load,
10.5 K. W.
Test Requirement: Paragraph 75 to be considered full load. To reduce
the load to three-quarters, one ⁷⁄₈-in. vacometer opening to be closed;
to produce one-half load, one ¹⁄₂-in. opening to be closed in addition
to the ⁷⁄₈-in. opening.
Bidders are requested to state in proposal the power consumption
required by their apparatus at full, three-quarters and one-half loads,
and in case the guarantees of the various bidders differ, they will be
evaluated as follows for the purpose of comparison:
For each full K. W. of power consumption or fractional part thereof
there will be allowed the following amount or proportionate parts for
fractional parts of a K. W. hour at the various loads:
Per Cent. of Full Load 100 75 50
Amount $156.00 $62.00 $94.00
As an illustration, let it be assumed that proposals have been received
offering equipment in accordance with specification requirements, and
the one offering the most economical apparatus based on guaranteed
power consumption names the highest price for the installation.
To determine if the purchaser will be justified in accepting the
highest proposal, let it be assumed that he has guaranteed a power
consumption of 1 K. W. less at full load, 0.75 K. W. less at
three-quarters load, and 0.25 K. W. more at half-load than the lowest
bidder. Under these conditions the algebraic sum of the saving of the
higher bidder over the lower bidder would be 156 + 46.50 - 23.50 = 179,
which is the additional amount in dollars which the purchaser would be
warranted in paying for the apparatus of higher efficiency.
In making the economy test to determine if the guaranteed power
consumption has been fulfilled, an integrating watt meter, previously
calibrated and found correct, will be placed in circuit and a two-hour
run made at each load and the power consumption based on the meter
readings.
=Penalty.=--It must be distinctly understood to be one of the
conditions under which bids are to be submitted for the work embraced
in this specification that the apparatus shall meet every requirement
of the specification and the guaranty for efficiency under which
conditions the contract price will be paid. In the event the apparatus
tested fails to meet the specified requirements for capacity or
economy, or both, the Architect shall have the right to reject the
apparatus, absolutely, and require the installation of satisfactory
apparatus, which shall comply with the contract requirements; or if
he elects to accept the same, in the event the capacity or efficiency
at any load (irrespective of other loads) is less than that named in
the proposal, then the contract price shall be the amount named in the
contract for a satisfactory plant, less the amount of deficiencies
shown by the test based on the following:
=For Capacity.=--$500.00 for each inch of vacuum and a proportionate
part thereof for each fraction of an inch below the 4 in. required in
vacometer when operating under full load.
=For Economy.=--Deduction for each K. W. or a proportionate part
thereof for each fraction thereof required in excess of guarantee.
Percentage of Full Load 100 75 50
Penalty $229.00 $93.00 $141.00
* * * * *
This evaluation was based on the same time of operation and cost of
current as that used in illustration under tests (Chapter XII).
The maximum power to be allowed for plants of various capacities should
be as follows:
Capacity in 100% 75% 50%
Sweepers of Load of Load of Load
8 24 20 17
6 20 18 15
4 14 12.25 10.5
2 7.5 ..... 6.25
In event that the plant is to be run with vacuum “on tap,” as in a
hotel, a guaranteed power consumption at no load should be required and
evaluated on the number of hours the plant will probably operate under
these conditions. This will be the largest item in the evaluation under
such conditions.
CHAPTER XV.
PORTABLE VACUUM CLEANERS.
While this book is primarily intended to deal only with vacuum cleaning
systems, which would limit the work to such apparatus as is permanently
installed within the building to be cleaned, the author considers that
it would not be complete without some mention of the portable cleaners
which are so popular at the present time.
On first consideration, the portable cleaner would appear to have a
considerable advantage over the stationary type in that the length
of hose is usually limited to not over 15 ft. and there is no pipe
line, which results in the elimination of practically all friction
loss, giving practically the same vacuum at the renovator as at the
exhauster. This should result in a saving of practically 50% of the
power required to operate the exhauster.
Referring to Chapter XII, we find that the power required to operate a
really efficient vacuum cleaning system is approximately 2.5 H. P. per
sweeper. If a portable cleaner, with the same efficiency and capacity,
be built, it would require at least 1¹⁄₂ H. P.
Such a cleaner would not be portable in the sense of the term as
applied to the most popular cleaners today. The same type has been
built on special order by the American Radiator Company, which mounted
its 1¹⁄₂ H. P. Arco Wand machine on a truck. This cleaner weighs
several hundred pounds and could be moved up and down stairs about
as easily as a sewing machine and would not be of any service in a
building not equipped with elevators. The power required to operate
this cleaner is also so great that special power wiring and large
capacity outlet plugs have to be installed throughout the building.
Such equipment has been provided in at least two department stores
where these cleaners are in use. This means that one wires his
building for vacuum cleaning instead of piping it, and there is also
the necessity of moving a heavy machine about to do the same work as a
stationary plant.
It would appear to the author that the cost of wiring would about equal
that of piping and that the additional labor required to move the
machine about would cost as much as the additional power needed by the
stationary exhauster.
This cleaner, as well as all other portable cleaners, discharges the
air from the exhauster directly back into the apartment cleaned, and is
open to the same objection that was raised against the early compressed
air cleaners. While all the dust may be caught by the dust bag, the
microbes are allowed to escape with the air and the cleaner is not a
sanitary device by any manner of means.
There are a few portable machines using rotary exhausters of the Root
type, and piston pumps, all of which are heavy to move about and, in
making them as light as possible, the efficiency of the exhauster has
been sacrificed. These machines will do the same quality of cleaning as
the stationary plants recommended for residence work and they require
about ³⁄₄ H. P., which is no less than is needed for a stationary plant
of the same capacity and efficiency.
The most popular type of portable cleaner is one which can be
attached to a socket or plug connected with the lighting system.
This should limit the power consumption to ¹⁄₈ H. P. However, many
of these cleaners use as much as 400 watts and a fair average for
cleaners retailing at about $125.00 is 250 watts. Such cleaners will
exhaust about 25 cu. ft. of air with a vacuum of 1 in. mercury at the
vacometer, a ⁵⁄₈-in. orifice being used. The theoretical power required
to move the air is approximately 50 watts and the overall efficiency
of these cleaners is, therefore, about 20%, as against 40% to 50% in
a good, one-sweeper stationary plant. The power expended in operating
these portable cleaners in proportion to the work done is no less than
with an efficient stationary plant.
Portable cleaners have been made in many types but practically all the
standard makes use one or two forms of vacuum producers, either the
diaphragm pump or the single or multi-stage fan. The pumps of the
former type are able to produce a vacuum as high as 6 in. to 10 in.
of mercury, when no air is passing, and will displace as high as 30
cu. ft. of free air per minute, when operated with a free inlet. They
produce about 1 in. of mercury at the carpet renovator when operated
on an ordinary carpet. When small-sized upholstery renovators are
used, a much higher vacuum is possible. When operated with bare floor
renovators or brushes, the quantity of air exhausted is not much over
20 cu. ft. per minute and they make very inefficient bare floor and
wall cleaners, but will do thorough carpet and upholstery cleaning
provided a small enough renovator is used.
Machines using a multi-stage fan will produce a maximum vacuum of
approximately 2 in. of mercury when exhausting no air, and will produce
a vacuum of approximately 1 in. of mercury when operated on an ordinary
carpet. With an unrestricted inlet, they will exhaust from 40 to 50 cu.
ft. of air per minute. When operated on a bare floor, they will exhaust
approximately 30 cu. ft. of free air per minute. They are, therefore,
more efficient floor cleaners than the pumps, but cannot do thorough
carpet and upholstery cleaning, no matter how small the renovator.
The smaller-fan type of machines, in which the fan is placed integral
with the carpet renovator and in which hose is not used in cleaning
floors or carpets, are provided with a single-stage fan. They produce
a suction of not exceeding ¹⁄₂ in. of mercury when no air is exhausted
and will exhaust from 5 to 10 cu. ft. of free air per minute when
operated on a carpet. With a free inlet they will exhaust from 15 to 20
cu. ft. of free air per minute. These machines are little if any better
than ordinary carpet sweepers.
Machines of this type are open to another objection in that the dust
bag is placed on the outlet of the fan and the dust in the bag is
continually agitated by the passage of the air, with the result that
all the finer particles of the dust are blown through the bag back into
the apartment. To be effective, the dust bag must always be placed on
the suction side of the exhauster and should be so arranged that the
dust will not quickly cover the entire area of the bag, for, when
this occurs, the suction is quickly reduced to such an extent that no
further cleaning can be done until the bag has been cleaned.
There is another type of mechanical cleaner manufactured by the Hoover
Suction Sweeper Company which is provided with a mechanically-operated
brush for loosening the dirt from the carpet. The dust is then conveyed
through a single-stage fan to a dust bag. The cleaner does not depend
on the vacuum to loosen the dirt and will do quite effective carpet
cleaning with a small expenditure of power. Owing to the small suction
produced, it is of little value for cleaning anything but carpets.
From the experience the author has had with portable vacuum cleaners,
some thirty makes having been tested for the Treasury Department by
him and by the Bureau of Standards, the use of such cleaners is not
considered as either an efficient or sanitary means of mechanical
cleaning.
If a cleaner requiring small power is required, one of the smaller
stationary plants, costing not over $300.00 and operating with ¹⁄₂ or
³⁄₄ H. P., is considered a better investment than $125.00 paid for a
portable cleaner.
If the purchaser feels that he cannot afford to pay more than $125.00
for his vacuum cleaner, a type such as the Water Witch can be
furnished for this price. This cleaner is placed in the basement, with
arrangements for starting same from any floor. The manufacturers state
that this apparatus produces a vacuum of 2 in. mercury in a carpet
renovator, 4 in. mercury in an upholstery renovator and exhausts 25 to
30 cu. ft. of free air per minute with open hose. The machine operates
by water pressure and the manufacturers state that it requires about
6 to 8 gals. of water per minute. All air is exhausted outside of the
building and all dust washed down the sewer with the exhaust water. It
is therefore, a fairly efficient and sanitary cleaning system.
The statements made above apply to parties who own their residences
and occupy offices in modern buildings. There are, besides these, a
great many who live in rented houses and apartments or occupy offices
in buildings where the owners are not sufficiently progressive to
install stationary cleaning plants. To supply the needs of this class
is evidently the field of the portable cleaner, as even the poorest of
these machines is more effective in the removal of dust and dirt than
the broom and carpet sweeper.
The selection of a portable cleaner by one who must necessarily resort
to the use of such a cleaner should be made with care. The motor should
be looked into and only one which has brushes readily removable and
one in which the condition of the brushes can be easily noted should
be selected. Lubrication is important. A good cleaner should be so
constructed that it can be operated for at least 100 hours without
relubrication.
The dust bag should always be on the suction side of the vacuum
producer and of such a design and construction that at least ¹⁄₂ peck
of a mixture of 40% sand, 30% flour, 15% sweepings and 15% Portland
cement can be picked up from the floor and retained in the bag and the
machine still be capable of picking up material from a bare floor.
A good test for capacity of a portable machine is to pick up ¹⁄₂ peck
of such material, then fit a thin disk with ⁷⁄₈-in. diameter opening
over the end of the hose. A machine, to be of any value, should show
a suction of 3 in. water and a first-class machine will show 8 in.
under these conditions. This will do fairly good bare floor work. To
ascertain if the machine will clean carpets, use a similar disk with
⁵⁄₈-in. diameter opening, when a suction of 7 in. water indicates the
lowest value and 16 in. about the best that can be obtained from any
portable cleaner. Cleaners must be readily portable and should not
weigh exceeding 75 lbs.
Transcriber’s Notes
Inconsistent and unusual spelling have been retained. In several
places the text appears to be incomplete or jumbled; this has not
been corrected. In many of the illustrations reference letters are
given in uppercase whereas the text uses lowercase letters; this has
not been standardised.
Inconsistencies and differences in wording and structure between the
Table of Contents and the text have not been rectified.
Page 83, paragraph starting Much of the hose in use today ...: as
printed in the source document; part of the text may be missing or
mixed up.
Changes made:
Illustrations and tables have been moved outside text paragraphs.
In some illustrations reference letters have been enhanced for the
sake of clarity; in Fig. 61 reference #1 has been added.
Obvious minor typographical and punctuation errors have been
corrected silently. In multiplications, the letter x and the
multiplication symbol (×) have been standardised to the latter.
Page 38, Table 2: F´ changed to F¹ cf. text.
Page 141: O´ changed to O¹ cf. Fig. 77a.
Page 149: ... by using metal shins ... changed to ... by using metal
shims ....
Page 170: ... the control (Fig. 107) ... changed to ... the control
(Fig. 97) ....
Page 205, item 33: ... approved made ... changed to ... approved make
....