Transcriber’s Notes
Italics, bold face and small capitals in the source document have
been transcribed _between underscores_, =between equal signs= and as
ALL CAPITALS, respectively.
More Transcriber’s Notes and an overview of changes made may be found
at the end of this text.
[Illustration:
_Frontispiece_
Welding School, Ordnance Department, United States Army, Peoria, Ill.]
WILEY ENGINEERING SERIES
OXY-ACETYLENE
WELDING MANUAL
BY
LIEUT. LORN CAMPBELL, JR., U.S.A.
_Officer in Charge of Welding Instruction,
Ordnance Department, U. S. Army._
TOTAL ISSUE, FIVE THOUSAND
NEW YORK
JOHN WILEY & SONS, Inc.
LONDON: CHAPMAN & HALL, LIMITED
1919
Copyright, 1919
BY
LORN CAMPBELL
_Copyrighted in Great Britain_
PRESS OF
BRAUNWORTH & CO.
BOOK MANUFACTURERS
BROOKLYN, N. Y.
PREFACE
(=1=) The oxy-acetylene method of welding and cutting metals has of
late been receiving considerable attention. Its tremendous power
of creating, repairing and destroying the work of man has been
but recently recognized in its broadest sense, and the demand for
operators, skilled in the manipulation of this apparatus, which
always has been far in excess of the supply, now knows no limit. Many
authorities have set forth their views and theories upon this subject,
in America and also in foreign countries. These have been published
from time to time in many of the leading periodicals and magazines, as
well as in book form. It seems the purpose of most of these works has
been to advance the operators who already have a smattering knowledge
of this art, or to present to the purchaser of apparatus a set of
operating instructions.
(=2=) It is singular indeed that a school manual, devoted exclusively
to the instruction of the beginner, which will serve as an aid to the
instructor as well as to the student, has not yet been put forth. It
cannot be said that there is not a demand for such. Recently there
seems to have been a mushroom growth of welding classes. The majority
of the vocational schools, colleges, night schools, and automobile
schools have all entered the instruction in oxy-acetylene welding on
their rolls and each is attempting to instruct in an entirely different
manner from the other. There can be no question as to the expediency
of affording the educational institutions a systematic as well as a
standardized method of instructing. But the books and articles of the
nature mentioned are not suited to this purpose, and were not designed
for it. A school-book is wanted; something to be used in the classroom,
to be employed as a reference in the shop practice, to be studied for
what it contains, and to indicate further lines of research, where such
are required.
(=3=) To meet this demand, the present “Manual” has been written to
serve the instructor as well as the student. In its preparation many
books, both well-known and obscure, have been examined and the methods
of shop instruction have been carefully studied by the author.
(=4=) It has been found that regardless of how fast the ground may
be covered in the lecture room, the average student’s power of
assimilation is limited and considerable time has been spent in
determining this ratio and applying it between the lecture subjects and
shop work.
(=5=) It must be remembered that while the chapters comprising the
theoretical part of this welding manual follow in the order given, the
actual shop practice, as previously mentioned, is the most important.
(=6=) Kindly aid has been received from many sources. Granjon &
Rosemberg, Kautney, M. Keith Dunham, S. W. Miller, Henry Cave, C.
J. Nyquist, P. F. Willis, Ben K. Smith, and others have embodied in
their writings many excellent ideas, which have assisted the author in
bringing out certain points advantageously. The following manufacturers
are to be given credit for many of the illustrations:
The Oxweld Acetylene Co., Newark, N. J.
The United States Welding Co., Minneapolis, Minn.
The Bastian Blessing Co., Chicago, Ill.
The Linde Air Products Co., New York City.
The General Welding & Equipment Co., Boston, Mass.
The Messer Manufacturing Co., Philadelphia, Pa.
The Alexander Milburn Co., Baltimore, Maryland.
The Torchweld Equipment Co., Chicago, Ill.
The Davis-Bournonville Co., Jersey City, N. J.
The K. G. Welding Co., New York City.
The Chicago Eye Shield Co., Chicago, Ill.
The Commercial Acetylene Supply Co., New York City.
The Welding Engineer, Chicago, Ill.
The Journal of Acetylene Welding, Chicago, Ill.
NOTE.--Lieut. Campbell offers his services without charge to anyone
interested in this method of welding and may be addressed care of
JOHN WILEY & SONS, INC., Publishers, 432 Fourth Avenue, New York City.
WILEY ENGINEERING SERIES
The Wiley Engineering Series will embrace books devoted to single
subjects. The object of the Series is to place in the hands of the
reader all the essential information regarding the particular subject
in which he may be interested. Extraneous topics are excluded, and the
contents of each book are confined to the field indicated by its title.
It has been considered advisable to make these books manuals of
practice, rather than theoretical discussions of the subjects treated.
The theory is fully discussed in text-books, hence the engineer who
has previously mastered it there, is, as a rule, more interested in
the practice. The Wiley Engineering Series therefore will present the
most approved practice, with only such theoretical discussion as may be
necessary to elucidate such practice.
CONTENTS
PAGE
INTRODUCTION 1
I. APPARATUS 19
II. OPERATION 27
III. SHOP EQUIPMENT 39
IV. APPARATUS REPAIRS 44
V. PREHEATING AGENCIES 51
VI. PART ONE--WELDING OF CAST IRON 58
PART TWO--WELDING OF CAST IRON 67
PART THREE--WELDING OF CAST IRON 70
PART FOUR--WELDING OF CAST IRON 75
VII. PART ONE--STEEL WELDING 81
PART TWO--STEEL WELDING 87
PART THREE--STEEL WELDING 92
PART FOUR--STEEL WELDING 97
VIII. BRASS WELDING 106
IX. PART ONE--ALUMINUM WELDING 109
PART TWO--ALUMINUM WELDING 113
PART THREE--ALUMINUM WELDING 118
X. WELDING OF MALLEABLE IRON 120
XI. OXY-ACETYLENE CUTTING 125
XII. CARBON BURNING 135
GLOSSARY 145
LECTURES 149
INDEX 167
Oxy-Acetylene Welding Manual
INTRODUCTION
(=1=) When choosing a life vocation, one generally views the
possibilities it has to offer and delves deeply into these, previous
to making a decision. It is therefore thought advisable at this time
to present the student with an idea of what is meant by oxy-acetylene
welding and cutting; how it is applied; the possibilities and
advantages attached to such an art.
(=2=) Acetylene gas, when burned with a proper portion of oxygen gas,
produces an extremely hot flame, in fact, the hottest flame known. Its
temperature is over 6000 degrees Fahrenheit. With this flame it is
possible to bring any of the so-called commercial metals, namely: cast
iron, steel, copper, and aluminum, to a molten state and cause a fusion
of two pieces of like metals in such a manner that the point of fusion
will very closely approach the strength of the metal fused. If more
metal of like nature is added, the union is made even stronger than the
original. This method is called oxy-acetylene welding and differs from
what the average layman considers welding in the blacksmith’s forge,
insomuch that there is no blow struck to assist fusion in this process.
And while the forge method is limited to wrought iron and steel which
is detachable and of restricted size and shape, the oxy-acetylene
process has, practically speaking, no such limitations.
[Illustration:
(_Courtesy of Acetylene Journal Publishing Co._)
FIG. 1.--Welders on an Ordnance Mobile Repair Unit in Action.]
[Illustration:
(_Courtesy of the Oxweld Acetylene Co._)
FIG. 2.--In Enameled Products for the Kitchen the Weld is Fast
Replacing the Riveting, Brazing, and Soldering of the Light Sheet Metal
Seams.]
(=3=) Manufacturers in the metal-working world were very slow to grasp
the real significance of this important process, until the operators
began demonstrating some of its possibilities. At the present time,
however, there is hardly a metal barrel or tank manufacturer who has
not discarded the old method of producing costly leaky, riveted drums
and containers, for this modern fusing process. The manufacturers of
fire-proof doors and windows, cooking utensils, seamless pipe and
tubing, office furniture and what not, are now virtually dependent upon
the welding torch at every turn.
(=4=) As a repairing agent, the welding torch has no rival. Whether
it is a casting of iron, steel, brass, or aluminum that has broken; a
boiler or tank that has worn away in spots, or an error on the part of
engineer, foundryman or machinist, the part can generally be reclaimed
and made stronger than originally. To-day practically no manufacturing
concern that is dependent upon metallic machinery could think of being
deprived of its oxy-acetylene apparatus, once having learned its worth.
In the not far distant past, were a gear or some casting to break, it
probably meant closing down the entire plant until a new part could be
obtained, which, whether the source of supply were near or at a long
distance, would mean costly delay. With oxy-acetylene equipment and an
efficient operator on hand, almost every emergency is provided for.
[Illustration:
(_Courtesy of the Oxweld Acetylene Co._)
FIG. 3.--Welding Broken Frame of 5-ton Automobile Truck.]
(=5=) If an automobile owner breaks a frame, he does not consider
replacing it with a new one, as the labor alone for stripping his
machine and setting it up again, not to mention the cost of the new
frame and the time required for this operation, is prohibitive. Rather,
he has his car taken to the nearest welder or his portable apparatus to
the car and the job is completed within thirty or forty minutes, with
the frame at the point of the break made stronger than ever. Locomotive
frames are handled in much the same manner, only more time is required
and perhaps extra operators, but the important point to be brought out
is the fact that on many jobs no dismantling is required and the repair
is permanently and quickly executed.
[Illustration: FIG. 4.--Staff of Instructors at the Ordnance Welding
School, U. S. A.]
(=6=) An interesting example of the true worth of welding was brought
to the attention of the public when the United States entered the
European War, and all the interned German vessels, which had been
greatly damaged by the orders of their commanding officers, were
restored to working condition with the oxy-acetylene and electric
welding process. This was considered impossible by many engineers not
familiar with the process, insomuch as they looked upon oxy-acetylene
welding as applicable only to small parts and here some of the
sections which had been blown or struck out of the cast cylinders,
etc., weighed many hundreds of pounds. In many instances the ribs
of these same vessels were cut most of their depth, but these were
restored to working order in a remarkably short time and the results
were more convincing than any words.
(=7=) Cutting with the oxy-acetylene process is just the opposite from
that of welding. The latter might be considered constructive and the
former destructive. In the case of welding, two parts are brought to a
molten condition along the line to be joined and both fused together.
Whereas in cutting, one piece of metal, when brought to a red heat, is
cut in two by an oxidizing flame. Cutting has not the wide scope that
welding has, for it can only be applied successfully at the present
day to wrought iron, rolled and cast steel. While it is limited in its
scope, the speed of this process in severing large masses of metal is
very spectacular and appeals forcibly to the observer.
(=8=) Probably the world’s first awakening to the real meaning of
oxy-acetylene cutting came when the U. S. battleship “Maine,” was being
taken from Havana Harbor. All the heavy armor plate and seemingly
immovable wreckage was cut into small sections which could be handled
easily. This was all accomplished with the cutting torch, which seems
to eat its way through metal with the same ease that a hot knife goes
through butter.
[Illustration:
(_Courtesy of the Oxweld Acetylene Co._)
FIG. 5.--Fireman Cutting ¹⁄₄-inch Steel Fire Door with Portable
Apparatus.]
(=9=) Before and since the time of the “Maine,” the cutting torch
has been accomplishing wonderful feats. In every scrap yard, old
boilers and the like are being cut into furnace size; speeding up the
production in answer to the world’s cry for more metal. The wreckage
on railroads and buildings using steel reinforcements is being cleared
in hours, with the aid of the cutting torch, where it required days by
other methods. Most of the fire departments in the larger cities now
carry the cutting torch as part of their equipment, and to it has been
credited the saving of many lives, by its timely cutting away of steel
doors, bars or barriers which prevented escape. Much of the plate in
this country’s shipbuilding yards is being cut to size right on the
job, and the function of this torch in cutting off risers measuring
from one to thirty-six inches in diameter in the foundry seems only to
be of secondary importance in comparison with some of its other uses.
In order to transport some of the largest inland lake boats which were
much too long to pass through the locks, to the sea, they were cut in
parts, transported, and later welded together and placed in service.
[Illustration:
(_Courtesy of the Acetylene Journal Publishing Co._)
FIG. 6.--Welders of the Signal Corps, U. S. Army, in Action.]
(=10=) It is not only possible to keep a cutting torch burning under
water, but it can also be made to cut. Contracting companies are
cutting off their piling under water and it has been known that in
European ports cutting has been successfully accomplished at a depth
of thirty feet. A special torch is employed by submarines to cut nets
under water.
(=11=) In reviewing the oxy-acetylene welding and cutting process, we
find that its growth is one of the most remarkable the world has ever
witnessed. About 1907 saw its industrial birth and since that time it
has advanced by leaps and bounds, rivaling the automobile industry in
its progress, despite the opposition and criticism levied at it by
workers of other trades and its careless and unskilled manipulation.
[Illustration:
(_Courtesy of the Acetylene Journal Publishing Co._)
FIG. 6_a_.--Welders of the Signal Corps, U. S. Army, in Action.]
(=12=) It is quite impossible to present anything like a complete list
of the applications of this process, but a few of its general uses are
here enumerated:
(A) _Airplane Construction._--Welding of frames, sockets, water and
gasoline tanks, water jackets and valve cages to cylinders, intake and
exhaust manifolds and connections, spark plug thimbles and the repair
of aluminum crank cases, etc.
[Illustration:
(_Courtesy of the Oxweld Acetylene Co._)
FIG. 7.--Welding a 2-foot Length of New Shafting on the End of a Motor
Shaft 2 Inches in Diameter.]
(B) _Automobile Manufacture._--Welding of steel and aluminum bodies,
transmission and rear axle housings, crank-shafts, cylinders, gears,
manifolds, pinions, crank cases, valves, rims, mufflers, frames,
fenders, wind-shield tubings, and uprights, etc.
(C) _Boiler Shops._--Welding and building up worn spots around
hand-hold plates, repairing cracks and checked portions of fire boxes,
retipping flues, connections, etc.
(D) _Brass and Copper._--Welding kettles, vats, tanks, stills, floats,
cooking utensils, manifolds, water jackets, electrical and chemical
wares, etc.
(E) _Commercial Welding._--Reclamation service on all kinds of metals,
quick and permanent repairs on all broken parts of machinery.
(F) _Electric Railway._--Welding air receivers on air-brake systems,
building up shafts, bonding the rails, motor housings, worn boxes,
reclaiming gears and broken trucks, steel trolley wires, etc.
[Illustration:
(_Courtesy of the Torchweld Equipment Co._)
FIG. 8.--This is a Steel Tank, Made of ³⁄₈-inch Plate, which Measures
30 Feet Long and 8 Feet in Diameter, Fused into One Piece by the
Welding Torch.]
(G) _Forge Shop._--Welding complicated parts which can not be
conveniently handled in the forge.
(H) _Foundries._--Welding up blowholes, porous spots, and reclaiming
castings in general. The cutting off of risers, gates, and heads on
steel castings.
(I) _Lead Burning._--Lead pipe joints, storage battery connections and
repairs, lead linings in vats, etc.
[Illustration:
(_Courtesy of Ben K. Smith, U. S. Welding Co._)
FIG. 9.--Locomotive Cylinder to be Welded in Place.]
(J) _Lumber Mills._--Building up worn shafts, repairing gears, chains,
and broken parts.
(K) _Machine Shops._--Rectifying errors on part of machinists and
engineers. A “putting-on” tool in every respect.
(L) _Manufacturers._--Welding spouts and handles on cooking utensils,
fire-proof doors and window sashes, office files and furniture, chains,
etc.
(M) _Mines._--Repairing pipe lines, boilers, broken shafts, gears, and
building up worn parts on dippers, etc. The cutting torch is used for
clearing away wreckage in case of accidents.
(N) _Pipe Work._--Welding of water, gas, and oil, steam and air lines.
High-pressure refrigeration systems are cut and welded in place.
[Illustration:
(_Courtesy of the Oxweld Acetylene Co._)
FIG. 10.--Steel Roll Top Desk--all Joints and Seams Welded. An
Excellent Example of High-grade Welded Metal Furniture.]
(O) _Plate Welding._--Tanks for oil, steam driers, digesters, vats,
chemical receivers, generators, etc.
(P) _Power Plants._--Welding of steam, air, and water-lines, of pump
castings, cylinders, pistons, worn or broken parts, etc.
(Q) _Railroad Work._--Reclaiming bolsters, couplings, slotting forged
engine rods, building metal cars, repairing fire-boxes, patching and
replacing side sheets, flue welding, building up frogs and crossings,
cutting off rails, mud rings, welding cracked cylinders, cross-heads,
steam-chests, building up worn spots on wheels, rims and pins, welding
spokes and locomotive frames, etc.
[Illustration:
(_Courtesy of the Oxweld Acetylene Co._)
FIG. 11.--Office Chair. Welded at all Joints.]
(R) _Rolling Mills._--Fabricating “open-hearth,” water jacket doors,
cutting up “lost heats,” scrap plates and bar stock billets. General
repairs of furnace equipment, hot beds, rolls, gears, engines, plates,
etc.
(S) _Sheet Metal._--Manufacture of tubing, oil-storage barrels,
metallic furniture, range boilers, etc.
(T) _Shipyards._--Cutting off plates and irregular shapes of steel,
channels, special sections. Building up of worn shocks, building and
patching hulls, stringers and the reclamation of propellers, posts and
broken parts of machinery, etc.
(U) _Structural Steel._--Cutting holes for rivets, gussets and splice
plates, and wrecking. Welding up misdrilled holes and machinist’s
errors. Cutting channels, I beams, and other shapes for coping,
splicing and fitting rails, welding reinforcing rods for concrete work
of any desired length and structural parts where bolting and riveting
is difficult or impossible.
[Illustration:
(_Courtesy of the British Oxygen Co._)
FIG. 12.--Cutting Armor Plate by the Oxy-acetylene Process.]
(V) _Scrap Yards._--Cutting up scrap boilers, tanks and other large
work to mill size, wrecking structural buildings, and reducing to small
size, reservoirs, tanks and boilers, which are housed in buildings to
remove them without damage to the structures.
(W) _Tractor Industry._--Cutting and welding frames, track and wheel
guards, water, gasoline, and oil tanks; welding up of blowholes, porous
spots and misdrilled holes in castings of all kinds.
[Illustration:
(_Courtesy of the Davis-Bournonville Co._)
FIG. 13.--Here is Illustrated an Oxy-acetylene Machine for Cutting
Holes in the Web of Rails, or in Structural Iron, of not more than ³⁄₄
Inch in Thickness. It can be Quickly Attached and Accurately Adjusted
to Pierce through the Iron Instantly, without any Previous Drilling,
and it will Cut Smooth Round Holes, from ¹⁄₂ to 2 Inches in Diameter in
from 30 to 60 Seconds. It is Particularly Adapted for Railroad Work,
and Enlarging or Cutting Holes in Building and Bridge Work.]
(=13=) The foregoing, as previously stated, is but a partial list of
some of the applications of the oxy-acetylene welding and cutting
process to various industries. What has the future in store for it?
Almost daily, some new application is found for it and at the present
time experiments are under way in boiler construction, the results of
which are not difficult to foresee. Giant hulls of seagoing vessels
are being fused together by welding and the limits of this wonderful
process which is now practically in its infancy are difficult to
forecast.
(=14=) During the World War many manufacturers of non-essentials shut
down and others turned their entire production over to the government,
changing their machinery and in most instances their entire plant.
What, then, are those who are operating machines and apparatus,
produced by these firms before the war, going to do for replacements?
There is but one answer, have their broken or worn out parts welded.
(=15=) Oxy-acetylene operators have always numbered far less than the
demand, a point which was clearly brought out by the government when
its immense Army and Navy were being formed. There were so few men
familiar with the oxy-acetylene process that it at once took measures
to establish its own schools where men could be trained, a thing that
the commercial world had been THINKING of doing for some years. As the
demand for operators continues to increase, it behooves a man, even
though he is not a metal worker, to think and apply himself, in order
that he may “carry on,” to the best advantage when opportunity knocks.
(=16=) The methods of instruction herein set forth are very simple
and while differing in many respects from those used by the trade,
have been most successfully employed in producing efficient operators.
Certain principles are instilled in the beginner and some of the
exceptions which are of minor importance are overlooked to avoid
confusion. Criticism is expected from those who have never engaged in
instruction of this kind on a large scale. There are many differences
to be expected on account of this very fact, for there are few who
have gone further than the instruction of very small classes where
individual attention may be given.
(=17=) All history of the process, gas manufacture and the like have
been omitted in order to give greater detail to the actual shop
practice and to have the operator become familiar with his apparatus
and thereby operate it with all due respect and intelligence.
(=18=) Oxy-acetylene welding cannot be learned by watching others
work, although observation may at times assist the beginner. Actual
torch practice, brain work and a power of “I will,” produce the most
efficient operators. For those who earnestly apply themselves to the
instructions which follow, there is every reason to believe that
success will be theirs.
CHAPTER I
APPARATUS
(=19=) Welding apparatus in general consists of two regulators equipped
with pressure gauges, two lengths of hose, and a welding torch. The
regulators are attached to cylinders of acetylene and oxygen and are
used to reduce and maintain a uniform pressure of these gases for
use at the torch. The gases at reduced pressure are conveyed to the
torch by the hoses. The regulators should each have a high-pressure
gauge to indicate the contents of the cylinder, and also a line or
working-pressure gauge to show the gas pressure on each hose. When the
gases reach the torch they are there mixed and combustion takes place
at the welding tip, which is fitted to the torch. Such an apparatus
is called portable, on account of its movability. There are other
equipments wherein one or both of the gases are generated, but these
will not be discussed here.
[Illustration: FIG. 14.--A Portable Welding Unit.]
(=20=) For convenience oxy-acetylene welding apparatus may be divided
into three classes, depending upon the principles used in securing the
fuel gas or acetylene for the flame. Low-pressure, medium-pressure and
high-pressure apparatus generally use about the same pressure of oxygen
and it will be called a constant. The acetylene gas is a variable and
in the low-pressure type only enough pressure is required to overcome
the friction of the line until it reaches the oxygen injector, located
in the torch, which acts as a syphon, drawing the acetylene gas to the
point of ignition. In a medium-pressure type about three-fourths as
much pressure is required on the acetylene line as on the oxygen. This
type is apt to verge on the injector type, as it depends to some extent
upon the oxygen under pressure carrying acetylene gas to the point
of ignition. In the high-pressure type equal pressure on each line
is used. To further make this classification clear, a certain sized
tip using, perhaps, 12 pounds of oxygen pressure can be used as an
example. In a low-pressure type perhaps 2 pounds pressure or less will
be needed on the acetylene line. On the medium-pressure approximately 9
pounds will be required, while on the high-pressure an equal amount, or
12 pounds will be needed.
[Illustration: FIG. 15.--Location of Mixing Chambers in Welding Torches.
(1) Shows gases mixing in the handle. (2) Has the mixing chamber in the
middle of the torch. (3) Illustrates how the gases are kept separate
until the head of the torch is reached. _Ox._ represents oxygen gas;
_Ac._ acetylene gas; and _m_ mixing chamber.]
(=21=) The mixing chambers for the gases may be located in the head;
in the middle of the torch, or in the handle. By mixing chambers
reference is made to that portion of the torch where the two gases
are brought together and mixed. As can be seen with three different
types of welding torches and three different locations for the
mixing of the gases, the manufacturers can find a large range for
producing oxy-acetylene apparatus. Some undoubtedly will fill certain
requirements better than others. Much, too, will depend upon the
ability of the operator in handling a torch.
(=22=) Flashbacks are caused by the improper mixture of the gases,
which increases the rate of flame propagation to such an extent that
the flame will flash back to the mixing chamber. Acetylene in a pure
state will burn very much slower than when mixed with equal parts of
oxygen. When more oxygen is introduced the flame propagation is much
greater, so that when an excess of oxygen is used, there is bound to
be considerable trouble from backflashing. When sufficient acetylene
is introduced to the mixing chamber, there is absolutely no chance for
this lean mixture to occur. If the flame flashes back to the mixing
chamber, both gases should be closed off immediately, at the torch, the
oxygen first, and then the acetylene gas.
(=23=) In some torches the heating of the mixing chamber will cause
a flashback and with these it is necessary to shut off the acetylene
and leave the oxygen valve just cracked and immerse the torch head in
water, dipping it slowly, so as not to cause too great a strain. The
oxygen will bubble out and prevent the water backing up in the tip.
If the flashback deposits enough soot on the inside of the tip and
the head to impair the working quality of the torch, the soot should
be removed by using a soft wire, preferably of copper, or some other
material which will not mar the tip.
[Illustration: FIG. 16.--Cross-section of Regulator.
_A_, chamber; _B_, nozzle; _C_, seat; _D_, seat arm; _E_, diaphragm;
_F_, cross-bar, or adjusting screw; _G_, diaphragm springs; _H_, gas
outlet; _I_, gas inlet.]
(=24=) It is interesting to note the action of a regulator, used
to reduce the cylinder pressure on both gases. The gas from the
cylinder, at high pressure, comes directly into the body of the
regulator or chamber (_A_), Fig. 16, through a fine nozzle (_B_). A
seat of gallilith, casenite, or fiber (_C_), attached to an arm (_D_),
presses against this nozzle. Arm (_D_), in turn, is attached to a very
sensitive diaphragm (_E_) and is moved every time there is a pressure
exerted on the latter. The movement of this diaphragm is controlled
by a handle or a screw, with a “cross-bar” attached to its end as is
shown at (_F_). This screw bears upon the diaphragm through the medium
of the springs (_G_). As this screw is forced inward the springs force
the diaphragm in, and thereby move the seat away from the nozzle of
the regulator. The gas, entering under high pressure, exerts an equal
force on all parts of the chamber and the diaphragm receives its
share. Now the chamber walls are made of a solid material, usually a
bronze or brass, and cannot be changed, but this diaphragm can be moved
and as this pressure is increased, the diaphragm is forced out and the
nozzle (_B_) is automatically closed by having the seat (_C_) brought
in contact with it. When gas is drawn off through the line (_H_), the
pressure within the chamber will naturally drop and as it does so,
the springs will force the diaphragm inward, permitting a replacement
of the gas drawn off. Although not noticeable, there is a continual
movement of this diaphragm whenever the gas is being used. It can be
readily seen that the amount of pressure within the regulator can be
accurately set by the tension of the spring against the diaphragm which
is controlled by the screw carrying the “cross-bar.”
(=25=) There are two types of regulators manufactured for the reduction
of gases under high pressure, depending upon the nature of work to be
done. The high-pressure regulator is employed for heavy work where a
great deal of gas is used and the regulator must pass it without much
effort, to prevent its freezing. This type of regulator is used on
cutting or on large welding work. It differs from the low-pressure
or ordinary type in four distinct features. Generally it contains a
much heavier diaphragm which is smaller in diameter, making it stiffer
in every respect. The tension springs which act upon this diaphragm
are much heavier. The nozzle which presses against the seat is much
larger, to permit the passage of a greater amount of gas. Then, too, a
larger working pressure gauge must be used, in order to read this high
pressure. In the welding of metals, especially in steel, the adjustment
of the flame is a very important matter, and absolutely dependable
regulation must be had. This is not possible with a high-pressure
regulator and is not intended to be so. The larger the diaphragm,
the more sensitive the regulator, and this point should be borne in
mind, and no small welding work attempted with the high-pressure
regulator. The reverse form of reasoning may be applied to low-pressure
regulators which have been used in cutting. They are very likely to
be strained and satisfactory results cannot be expected, for they
are not made for that purpose. Acetylene regulators are constructed
much more sensitively than the oxygen regulators, to take care of the
lower pressure of gas and in a sense might be called weaker, insomuch
that the larger nozzle which passes the gas is closed or regulated by
springs which are not nearly as strong as in the oxygen regulator. For
this reason acetylene regulators cannot be interchanged with oxygen
regulators for they will not stand the pressure demanded in the first
place, and in the second place, were a small quantity of acetylene gas
left in the regulator and oxygen introduced, an inflammable mixture
would be formed which is not advisable to have present, on account of
its explosiveness. In many instances oxygen regulators are put out
with the copper diaphragms, whereas another metal must be used on the
acetylene regulators, because acetylene gas attacks copper and usually
a German silver or rubber diaphragm is used. On account of the lower
pressures used in charging the acetylene cylinders, lower pressure
gauges are used than on oxygen regulators.
(=26=) All tension should be removed from the diaphragm springs
by screwing out on the “cross-bar” (that is, to the left), before
admitting gas under pressure to the regulator to avoid abusing the
seat. If a matter of 1800 pounds pressure were admitted suddenly into
any regulator that had the seat removed from the nozzle, there would be
a sudden exertion upon the diaphragm, which would draw the regulator
seat up very violently against the nozzle, and if it did not crack the
seat it would undoubtedly groove it to such an extent that it would
leak and a trouble known as “creeping regulator” would result. If this
occurs, good work cannot be expected because the flame will not remain
steady, and it is therefore necessary to take steps to rectify this
abuse. If there is a welding company available, the regulator should be
sent to it for repairs, but if the operator is in an isolated district
when this occurs, and must have some means of continuing work, it will
be possible for him to remove the seat by unscrewing the back of the
regulator. If the seat has become grooved, and he thinks that this is
the trouble, many times the seat can be turned over and the machined
surface on the other side used. If the seat is cracked, however, about
the quickest way of making an emergency repair is to turn out a new
seat from hard rubber or fiber on a lathe.
(=27=) In acetylene cylinders an absorbent called acetone is generally
used, which gives up the gas as required. A full cylinder can be used
for some time without any noticeable difference in the gauge reading,
and then, as it nears the empty point, the gauge reading will drop very
perceptibly. It is therefore impossible to depend upon a high-pressure
acetylene gauge as an index to the contents of the cylinder. The only
method known to correctly check the amount of acetylene gas on hand
is to weigh the cylinder. There are 14¹⁄₂ cubic feet of acetylene
gas to the pound, and when the net weight of the cylinder is given
the contents can readily be figured. A tag bearing the net weight or
figures which will permit its computation is generally found attached
to each acetylene cylinder. In the case of oxygen cylinders, there
being no absorbent used, the contents of the cylinder is indicated on
the high-pressure gauge. On the latest type gauge the contents will be
shown by cubic feet, by pounds pressure and by atmospheric pressure, to
facilitate the computation of costs by the operator.
(=28=) Occasionally a needle valve on a torch will begin to leak
and it will be found necessary to grind it. Realizing that oil and
grease are not to be used where oxygen is in evidence, the question is
often brought up as to the proper lubricant to be used in doing this
kind of work. Glycerine is used by most manufacturers, together with
powdered glass or flour emery. In doing work of this kind the finished
job is thoroughly washed with ether. Occasionally when piping oxygen
lines through the shop, a screwed coupling will leak and there is a
temptation to calk the same with white lead, but this should never be
done, rather use lead oxide mixed with the glycerine for this purpose
as it forms a paste which sets very rapidly and forms a hard, tough
compound.