Improvements in Methods of and Means for Manufacturing Metal Tubing and in Utilizing the Heating Effect of Electrical Energy in connection therewith
Year: 1898

page_text: Date of "Application, 22nd Oct., 1898
Complete Specification Left, 24th July, 1899-Accepted, 21st Oct., 1899
Date of Application, 22nd Oct., 1898
Complete Specification Left, 24th July, 1899-Accepted, 21st Oct., 1899
PROVISIONAL SPECIFICATION.
Improvements in Methods of and Means for Manufacturing Metal
Tubing and in Utilizing the Heating Effect of Electrical Energy
in connection therewith,
I, ELIAS ELKAN RIES, of No. 4 West 115th Street, New York City, in the
County of New York and State of New York, one of the United States of
America, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements in methods of and means or apparatus
for manufacturing metal tubing from webs or strips of metal; and its object
is to produce tubing in which the meeting edges are welded together in such
a manner that the tubing may be redrawn cold without weakening the joint,
a process only possible heretofore with ingot or weldless formed tubing.
A further object of this invention is to utilize the heating effect of an electric
current or currents for producing an electrically welded or brazed seam during
the process of forming tubes of this character, by which the heat is locally
applied and the heated metal protected to a very appreciable extent from oxida-
tion and products of combustion, thus materially increasing the perfection and
strength of the seam, and making this portion of the tube practically as strong
or stronger than any other portion. I am also enabled by my improvements
to manufacture tubes substantially equal in all respects, as regards strength
and appearance, to seamless drawn tubing, while at the same time diminishing
greatly the cost of production, both with respect to the number of operations
required, the increased uniformity of the product, the saving effected in the
original cost of plant and of the greater economy in the use of heat.
Prior to my invention it has been proposed to make tubing from webs of
metal and weld the meeting edges together by first heating the flat web to a
welding temperature in a furnace and then form the heated web into a tube, after
which the meeting edges were forced together and welded. This of course
necessitated the heating of the entire web to or above a welding temperature
and entailed a great waste of heat, besides the constant danger of inclosing
metal oxide in the joint and thereby weakening the same; also the metal
cooled to some extent in passing from the furnace to the tube-forming and weld-
ing apparatus, and therefore it was necessary at times to employ a gas or oil
flame to maintain the metal at the meeting edges at a welding temperature
This only served to include products of combustion in the joint, thereby weaken-
ing the same. It has also been proposed to use for thin and for easily-fusible
metals a flame applied to the meeting edges just prior to the welding operation
as the only source of heat; but this did not avoid the weakening of the joint
by the incorporation therein of the products of combustion. For these reasons
welded tubing has never been able to compete with weldless tubing. By my
invention, however, I have overcome the various objections to welded tubing
and am able to produce welded tubing equal in every respect to weldless tubing

page_text: and in some respects superior to it, besides effecting a considerable economy
in its manufacture and avoiding many of the time and labor consuming opera-
tions incident to the manufacture of seamless tubing from solid or hollow ingots
or disks as now practiced.
.
§
My invention consists in first forming a web into a tube without preliminary
heating, except in the case of very large and thick webs, when only sufficient heat
is applied to facilitate the folding of the web into a tube. The preliminary
heating in such exceptional cases is always very much below a welding tempera-
ture, so that for all practical purposes the web may be said to be cold when
folded into a tube, and since in the great majority of cases in the practice of
my invention, the web is actually cold when folded into a tube and is never
highly heated preliminary to folding it into a tube, even in exceptional cases,
the web will hereinafter be referred to as being folded into a tube when cold
with the understanding that the term includes the exception noted. Having
folded the web into a tube, when in a cold state, I heat the meeting edges, only
to a welding temperature, either just before or shortly after they come into
contact, by means of heat generated by an electric current. The heat may be
generated by springing an are between the meeting edges and the terminal of
an electric circuit, or the arc may be formed adjacent to the meeting edges
between two terminals of the electric circuit, or the current may be passed
directly through the formed tube, so that the higher resistance offered by the
meeting edges will cause them to be heated to the desired welding temperature.
As soon as the meeting edges have become sufficiently heated they are forced
together and upset, thereby completing the weld.
:
In the case of very thin tubes formed of light gauge metal, such for example
as certain kinds of bicycle tubing, where the metal is likely to be burned or
otherwise injuriously affected by any sudden increase or variation in heat that
might result from the direct application of the electric arc to the tube, or from
the passage of an electric heating current therethrough in the manner just men-
tioned, and which would not affect tubes made from heavier gauge metal, I
heat the meeting edges to the desired welding temperature after the shaping
or forming of the tube, preferably as it emerges from the shaping or forming
die, by means of heat radiated from a suitable electrical furnace or other elec-
trical resisting medium located parallel with and in effective heat radiating
proximity to the meeting edges of the tube or a portion thereof, said furnace
or other resisting medium being enclosed in a suitable refractory casing pro-
vided with a narrow longitudinal slot or opening along its upper surface that
is arranged to be covered by the abutting or overlapping edges of the tube as
the same are being heated and united.
:
By means of this arrangement I am enabled, without directly subjecting the
metal to the action of an electric arc or causing the passage over the same of
an electric current the regulation of which may be interfered with to a greater
or less extent by causes that may react injuriously upon the weaker metal of
the class of tubes now under consideration, to produce continuously and effec-
tively the welding temperature necessary to cause the heated edges to coalesce
and unite as the tube is in process of formation, or if preferred the heating
and welding of the tube by my improved process may be effected as a separate
operation or step at any time subsequent to the formation or shaping of the tube.
I furthermore provide by this process a source of heat for the metals about to
be welded, brazed or otherwise united that is perfectly pure and free from all
products of combustion; that is under the most perfect control and the inten-
sity of which can be regulated to suit the speed of the shaping or welding
process; that enables me to protect the surfaces to be united against atmo-
spheric oxidation, and that, by reason of the perfect localization and confine-
ment of the heat to the exact point or points where it is required, permits me
to produce tubing with a degree of economy in heat energy not heretofore
attainable. In short, by my process I am enabled to form and weld the tubes

page_text: continuously and progressively and can regulate the heat and localize its action
to a nicety. By using the electric current as a source of heat I avoid the use
of a furnace and the emergency reheating by gas or oil flame with the unavoid-
able incorporation of the products of combustion in the joint and the conse-
quent weakening of the same, and can manufacture tubes of various kinds
having practically the same properties as seamless tubes at a small fraction of
the cost.
I am well aware that electric heating as applied to the working of metals,
whether by the arc or by simply passing current through the joint, was known
prior to my present invention, and I lay no claim to such matters; but I have
discovered that by utilizing the heat generated by the electric current as a step
in the process of manufacturing tubing from webs of metal I not only do away
with the heating-furnace and gas oil flames heretofore deemed necessary for the
formation of welded tubing, but in addition to being able to reduce the plant
necessary I am enabled to produce tubing fully equal to weldless tubing, and I
do this at a much less cost. In addition thereto the length of the tubing is not
limited by the size of the ingot, as in weldless tubing, but may be of prac-
tically unlimited length, depending only on the length of the web, which latter
may be very long. I have furthermore found that by means of the exact localiza-
tion of the heat in my process I am able to produce welded tubes from flat
strips or webs without the aid of any external pressure upon the heated
edges other than that due to the spring pressure imparted to the tube itself by
its passage through the forming-dies, as will appear more fully hereinafter. I
have also found that tubes thus produced by my process may be subjected to
one or more redrawing operations without any apparent weakening of the joint
or seam, and thereby be finished to size with a perfectly smooth wall, so that
the seam cannot be detected and in such a manner as to present an appearance
in all respects identical with that of a seamless drawn tube.
In carrying out my improved process I employ a draw bench or tube
drawing machine of any ordinary or desirable construction. This machine
I feed with a web or strip of steel, iron, brass or other metal cut to
such a width as, when folded into tubular shape, will cause it to form
a tube of approximately the desired diameter. The end of the web is fed
through a die over a mandrel, the shape and relative diameters of which are
preferably such that the metal of the tube will be subjected to a slight drawing
operation and at the same time condensed in such a manner that the sides of
the tube thus formed will abutt, after leaving the mandrel and die, with a firm
spring pressure tending to close the same. I have discovered as the result of
experiments to this end, that by properly shaping the head of the mandrel and
the die a very strong closing pressure can be thus obtained in the tube, which I
utilize in some cases in lieu of a separate clamping device as a means for forcing
the edges of the tube together to produce the weld when they have been heated
to the requisite temperature.
According to one form of my invention, adapted more particularly to the
larger and heavier class of tubes, the edges of the tube are heated to the proper
temperature for welding by an electric arc or arcs established between the metal
of the tube and one or more carbon or other electrodes, or between two or more
pairs of such electrodes, that are adjustably mounted upon the head or frame-
work of the draw-bench so that their ends may be brought into position to
spring the arc or arcs at a point just in advance of the meeting edges of the tube,
the welding pressure being imparted during their passage through the die, which
latter is in this case of special design and is preferably kept cool by a circu-
lating fluid or other equivalent means.
Where the tubes to be manufactured are smaller size and of somewhat lighter
gauge, I modify the arrangement just described by folding and passing the web
through the die and then as it emerges therefrom subjecting it along the line
of the joint to the heating effect of the arc or arcs as the tube is drawn along

page_text: under the same, a suitable screen for the eyes and means for adjusting and con-
trolling the arc or ares being provided. The cooling type of die may be dispensed
with in this arrangement and the tube may if desired be passed through a
spring pressed supplemental die or clamping device to assist in producing or
maintaining the welding pressure until the joint has become effectively united..
Instead of using the electric arc as the heating medium, I sometimes provide
a reducing die in addition to the shaping die, which are separated a short dis-
tance apart, and in such case may constitute the shaping and reducing dies as
the terminals of an electric heating circuit supplied with current from the
secondary or thick wire coil of an inductional convertor, or from a storage
battery, dynamo, or other direct current source, and organize the apparatus in
such a manner that the heat imparted to the tube is concentrated along the
line of the joint over that portion embraced between the shaping and reducing
dies, the pressure imparted to the tube by the shaping die causing the heated
edges to coalesce and unite, while the joint thus formed is further condensed
and finished in its passage through the reducing die.
A modification of this process consists in providing an insulated shaping die
and an insulated mandrel for the same adapted to engage with the edges of the
tube in advance of its contact with the die, said die and mandrel forming the
terminals, respectively, of an electric heating circuit, a narrow strip or portion
of the tube edges being thus heated and immediately thereafter welded in its
further passage through the die. To prevent the heated edges from becoming
dragged and torn, in those structures embodying my invention wherein the
meeting edges of the web are heated before they are brought into contact, I
may cut a slight ridge or depression in the die or mandrel along the line of the
seam, or I may form the mandrel with a globular head and eccentrically journal
therein a friction roller with its periphery flush with the surface of the mandrel-
head. This roller is arranged to rotate in the direction of the line of travel of
the web and in contact with the meeting edges of said web, so that these edges
when heated are not dragged or torn on passing over the mandrel. In conjunc-
tion with said mandrel, either as a substitute for or as supplemental to the
usual stationary shaping die, I may use a set of forming-rolls between which
the web, already partly completed by the body of the die, is drawn to force the
edges constituting the seam into contact.
In cases where I provide the die or mandrel with a ridge or depression as
above stated, the joint of the tube will be formed with a slight ridge or rein-
forcement which adds to its strength at the seam, but where such reinforcement
in the finished tube is not desirable, I provide for flattening the same and thereby
still further condensing the metal and increasing the strength of the joint, either
by a gradual contraction of the ridged portion of the die to the normal diameter
of the die proper at the point where the tube emerges from it, or by a subsequent
drawing operation with or without electrically reheating the tube, or the seam
thereof, according to the character and condition of the metal of which the tube
is composed and the thickness and diameter of the same. I have found that,
except in the case of very thick walled tubes, the meeting edges may be heated
and welded by my process so effectively and rapidly that the body of the tube
up to within a very short distance of the line of the joint remains practically
cold, thereby not only permitting the welding of the joint by the uniform pres-
sure exerted
upon it by the main body of the tube, but enabling me to produce
such weld during the shaping and drawing process without unduly drawing or
extending the metal of the tube as would be the case if the entire body of the tube
were heated, and, as before stated, with great economy in the expenditure of
energy for heating purposes.
very
Where the tubes to be welded, brazed or otherwise united are to
be formed from
thin webs
as
of metal, such
tubes intended
for bicycle frames, interior electric wire ducts, gas pipe, rain spout-
ing, etc., etc., I prefer to employ as the proximate source of heat

page_text: 18
a resisting conductor or mass of resisting conducting material that
heated to intense incandescence by the passage therethrough of an electric current
or currents. The incandescent body or surface is of elongated form and is pre-
ferably secured to the framework of the draw bench at the point where the
tube emerges from the forming die. The web is preferably fed into the die in
this instance from a reel or otherwise at a point above the mandrel, so that the
abutting or overlapping edges or seam as the same emerges from the die is at
the lowest portion of the tube. The incandescent conductor or material is
enclosed within a small elongated chamber formed of refractory insulating
material, such as chalk, fire brick or the like, containing binding posts or elec-
trodes forming the terminals to which the conductors from the source of heating
current are attached. This chamber is open at its central upper portion and
curved so as to embrace that portion of the tube adjacent to the meeting edges
and including the latter, so that the moving tube as it is drawn through the
die by the traveller of the draw-bench constitutes the cover for the chamber.
The incandescent surface of the electrical conductor or furnace is thereby brought
as close as possible to the moving seam and within effective heat radiating
proximity to the same without actually touching the tube, while the refractory
non-conducting walls of the furnace thus constituted effectually prevent the
appreciable escape or radiation of heat to the surrounding atmosphere or to the
body of the tube not directly included over the radiating slot, and at the same
time prevent any access of the atmosphere to the edges of the metal being
heated. The electrical heat thus produced is in its purest state, since there are
no products of combustion and the progressive movement of the tube, owing
to the somewhat elongated shape of the radiating surface, insures a gradually
increasing increment of the heat being imparted to the seam up to the maximum
welding and uniting temperature, without unduly heating or injuring the thin
metal of the web and without the deposit therein of any foreign matter that
might otherwise interfere with the production of a perfect weld. In some cases
I may supplement the external radiator with an internal radiator forming a
projection of or removably attached to the head of the forming mandrel so as
to project for a short distance into the interior of the tube at a point directly
over or in alignment with the external radiator, so that both the inner and outer
surfaces of the seam may be simultaneously heated. Suitable means are pro-
vided for controlling and regulating the flow of current to the radiator or
radiators and to adjust the intensity of the heat radiated by them to suit the thick-
ness or gauge of the tube and the speed with which the same is drawn through
the die by the traveller. I also provide for automatically or manually cutting
of or reducing the flow of current at such times when the end of a new web or
strip is introduced into the forming die, and also for swinging or depressing the
external radiator out of the way, where this should be found necessary, to
enable the traveller-clamp to approach close to the die to clutch the end of a
newly introduced web or strip.
Although I have herein more particularly referred to one feature of my
process which embodies the simultaneous forming and welding of the tube, I
do not desire to be limited to this mode of practising my invention, since it
will be obvious that I may first form the tubes from suitable webs or strips
of the proper width either by drawing or rolling and with either straight or
spiral seams, and with butt or lapping joints, and then weld the same electric-
ally by any one or more of the methods described, as a subsequent and inde-
pendent operation. The particular mode of procedure. selected by me will
necessarily depend largely upon the nature and character of the tubes to be
produced and the service for which they are to be employed.
Furthermore, while I have heretofore mentioned various methods of locally
applying or developing the desired heat in my improved process of tube manu-
facture, I am not necessarily limited to the employment of electrically developed
heat in all cases, for the reason that when tubing is made from the web by the

page_text: passage of such web through my improved mandrel and forming die which
imparts to the tube the quality of self-contained spring pressure tending to firmly
close or press together the previously trimmed abutting edges of the web or
tube, I find that the joint thus formed may be successfully heated to the welding
temperature by any ordinary source of heat, such as a gas or oil fiame, without
danger of oxidizing the abutting edges or of depositing foreign matter upon the
same to an extent that would otherwise interfere with their perfect union.
In addition, however, to the various electrical methods of developing the
requisite heat heretofore mentioned, I propose in some cases to employ in con-
nection with my process of tube manufacture what is known as the electrolytic
method of heating metals. That is to say, I may constitute the forming die
or rolls through which the tube passes or the tube itself, one terminal of an
electric circuit, and pass the moving seam of the tube in contact with a specially
arranged stationary electrolytic bath constituting the other terminal and arranged
in operative proximity thereto. This modification of my process is more espe-
cially applicable to the manufacture of coiled or spiral tubing for heating and
refrigerating purposes, although it is likewise applicable for other varieties of
tubular structures.
I have also found that where light gauge tubes made by my improved process
require to be reheated or annealed either for the purpose of further reducing
or redrawing them or for the other reasons, that my process of heating pro-
gressive sections of the tube electrically possesses numerous advantages, inasmuch
as they may be perfectly annealed or reheated to any desired temperature,
without recourse to expensive and time consuming annealing furnaces, while
they are being fed into the reducing die. For this purpose I make use of a
modification of my electric radiating furnace which is constructed so as to admit
of the passage of the tube therethrough immediately in advance of the reducing
die or other device into which the annealed tubes are to be fed. In the case
of very small and thin tubes I have also been successful in annealling progres-
sively moving sections of the same inductively, by constituting that portion of
the tube to be heated the moving secondary of an induction coil whose stationary
primary winding is in inductive relation therewith and is surrounded by a suit-
able magnetic shield to enclose the lines of force, the primary coil being
connected to a source of alternating electric currents and a reactive coil or other
variable controlling device being included in the circuit to maintain the desired
temperature.
!
While I have described my process as applied to the manufacture of tubes
from webs in which the webs are moved and in which the heating devices are
stationary, I do not desire to be understood as limiting myself to such mode,
as the novel features of my process may in many cases be applied with equal
advantage to the seaming or welding of tubes or pipes in which the latter are
stationary and in which my various heating devices form the portable or movable
elements, without departing from the scope or spirit of my invention.
Dated this 1st day of October 1898.
Improvements in Methods of and Means for Manufacturing Metal
Tubing and in Utilising the Heating Effect of Electrical Energy
in connection therewith.
I, ELIAS ELKAN RIES, of No. 4 West 115th Street, New York City, in the
County of New York and State of New York, one of the United States of
America, Electrical Engineer, do hereby declare the nature of this invention,

page_text: and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
This invention relates to improvements in methods of and means or apparatus
for manufacturing metal tubing from webs or strips of metal; and its object
is to produce tubing in which the meeting edges are welded together in such
a manner that the tubing may be redrawn cold without weakening the joint,
a process only possible heretofore with ingot or weldless formed tubing.
A further object of this invention is to utilize the heating effect of an electric
current or currents for producing an electrically welded or brazed seam during
the process of forming tubes of this character, by which the heat is locally
applied and the heated metal protected to a very appreciable extent from oxida-
tion and products of combustion, thus materially increasing the perfection and
strength of the seam, and making this portion of the tube practically as strong
or stronger than any other portion. I am also enabled by my improvements
to manufacture tubes substantially equal in all respects, as regards strength
and appearance, to seamless drawn tubing, while at the same time diminishing
greatly the cost of production, both with respect to the number of operations
required, the increased uniformity of the product, the saving effected in the
original cost of plant and of the greater economy in the use of heat.
.
Prior to my invention it has been proposed to make tubing from webs of
metal and weld the meeting edges together by first heating the flat web to a
welding temperature in furnace and then form the heated web into a tube, after
which the meeting edges were forced together and welded. This of course
necessitated the heating of the entire web to or above a welding temperature
and entailed a great waste of heat, besides the constant danger of inclosing
metal oxide in the joint and thereby weakening the same; also the metal
cooled to some extent in passing from the furnace to the tube-forming and weld-
ing apparatus, and therefore it was necessary at times to employ a gas or oil
flame to maintain the metal at the meeting edges at a welding temperature.
This only served to include products of combustion in the joint, thereby weaken-
ing the seam. It has also been proposed to use for thin and for easily-fusible
metals a flame applied to the meeting edges just prior to the welding operation
as the only source of heat; but this did not avoid the weakening of the joint
by the incorporation therein of the products of combustion. For these reasons
welded tubing has never been able to complete with weldless tubing. By my
invention, however, I have overcome the various objections to welded tubing
and am able to produce welded tubing in every respect equal to weldless tubing
and in some respects superior to it, besides effecting a considerable economy
in its manufacture and avoiding many of the time and labor consuming opera-
tions incident to the manufacture of seamless tubing from solid or hollow ingots
or disks as now practiced.
My invention consists in first forming a web into a tube without preliminary
heating, except in the case of very large and thick webs, when only sufficient heat
is applied to facilitate the folding of the web into a tube. The preliminary
heating in such exceptional cases is always very much below a welding tempera-
ture, so that for all practical purposes the web may be said to be cold when
folded into a tube, and since in the great majority of cases in the practice of
my invention, the web is actually cold when folded into a tube and is never
highly heated preliminary to folding it into a tube, even in exceptional cases,
the web will hereinafter be referred to as being folded into a tube when cold
with the understanding that the term includes the exception noted. Having
folded the web into a tube, when in a cold state, I heat the meeting edges only
to a welding temperature, either just before or shortly after they come into
contact, by means of heat generated by an electric current. The heat may be
generated by springing an are between the meeting edges and the terminal of
an electric circuit, or the arc may be formed adjacent to the meeting edges,
between two terminals of the electric circuit, or the current may be passed

page_text: directly through the formed tube, so that the higher resistance offered by the
meeting edges will cause them to be heated to the desired welding temperature.
As soon as the meeting edges have become sufficiently heated they are forced
together and upset, thereby completing the weld.
In the case of very thin tubes formed of light gauge metal, such for example
as certain kinds of bicycle tubing, where the metal is likely to be burned or
otherwise injuriously affected by any sudden increase or variation in heat that
might result from the direct application of the electric arc to the tube, or from
the passage of an electric heating current herethrough in the manner just men-
tioned, and which would not so affect tubes made from heavier gauge metal, I
heat the meeting edges to the desired welding temperature after the shaping
or forming of the tube, preferably as it emerges from the shaping or forming
die, by means of heat radiated from a suitable electrical furnace or other elec-
trical resisting medium located parallel with and in effective heat radiating
proximity to the meeting edges of the tube or a portion thereof, said furnace
or other resisting medium being enclosed in a suitable refractory casing pro-
vided with a narrow longitudinal slot or opening along its upper surface that
is arranged to be covered by the abutting or overlapping edges of the tube as
the same are being heated and united.
44
By means of this arrangement I am enabled, without directly subjecting the
metal to the action of an electric arc or causing the passage over the same of
an electric current the regulation of which may be interfered with to a greater
or less extent by causes that may react injuriously upon the weaker metal of
the class of tubes now under consideration, to produce continuously and effec-
tively the welding temperature necessary to cause the heated edges to coalesce
and unite as the tube is in process of formation, or if preferred the heating
and welding of the tube by my improved process may be effected as a separate
operation or step at any time subsequent to the formation or shaping of the tube.
I furthermore provide by this process a source of heat for the metals about to
be welded, brazed or otherwise united that is perfectly pure and free from all
products of combustion; that is under the most perfect control and the inten-
sity of which can be regulated to suit the speed of the shaping or welding
process; that enables me to protect the surfaces to be united against atmo-
spheric oxidation, and that, by reason of the perfect localization and confine-
ment of the heat to the exact point or points where it is required, permits me
to produce tubing with a degree of economy in heat energy not heretofore
attainable. In short, by my process I am enabled to form and weld the tubes
continuously and progressively and can regulate the heat and localize its action
to a nicety. By using the electric current as a source of heat I avoid the use
of a furnace and the emergency reheating by gas or oil flame with the unavoid-
able incorporation of the products of combustion in the joint and the conse-
quent weakening of the same, and can manufacture tubes of various kinds
having practically the same properties as seamless tubes at a small fraction of
the cost.
I am well aware that electric heating as applied to the working of metals,
whether by the arc or by simply passing current through the joint, was known
prior to my present invention, and I lay no claim to such matters; but I have
discovered that by utilizing the heat generated by the electric current as a step
in the process of manufacturing tubing from webs of metal I not only do away
with the heating-furnace and gas oil flame heretofore deemed necessary for the
formation of welded tubing, but in addition to being able to reduce the plant
necessary I am enabled to produce tubing fully equal to weldless tubing, and I
do this at a much less cost. In addition thereto the length of the tubing is not
limited by the size of the ingot, as in weldless tubing, but may be of prac-
tically unlimited length, depending only on the length of the web, which latter
may be very long. I have furthermore found that by means of the exact localiza-
tion of the heat in my process I am able to produce welded tubes from flat

page_text: strips or webs without the aid of any external pressure upon the heated
edges other than that due to the spring pressure imparted to the tube itself by
its passage through the forming-dies, as will appear more fully hereinafter. I
have also found that tubes thus produced by my process may be subjected to
one or more redrawing operations without any apparent weakening of the joint
or seam, and thereby be finished to size with a perfectly smooth wall, so that
the seam cannot be detected and in such a manner as to present an appearance
in all respects identical witli that of a seamless drawn tube.
In the accompanying drawings, forming part of this specification, Figure 1
is a side elevation partly in section, of a tube-making machine constructed in
accordance with my invention and in which one mode of producing arc-welded
tubes is shown. Fig. 2 is a longitudinal section, partly in elevation, of a portion
of a pipe-making machine, showing a modified form of apparatus. Fig. 3 is
an elevation of a clamp constituting a detail of the structure shown in Fig. 2,
with the tube in place, the latter being shown in section. Fig. 4 is a longitudinal
vertical section of the tube-forming die shown in Fig. 1. Fig. 5 is a side elevation
of a portion of a tube-making machine, illustrating the invention. Fig. 6 is
a similar view showing a modification. Fig. 7, is a longitudinal section of a
portion of a tube-making machine in which the meeting edges are heated by
the passage of the electric current through the metal of the tube adjacent to
the edges. Fig. 8 is a plan view of the mandrel used in the machine shown in
Fig. 7. Fig. 9 is a cross-section through the middle of the die of the structure
shown in Fig. 7. Fig. 10 is a cross-section through a die such as shown in
Fig. 1, illustrating a detail of construction. Fig. 11 is a longitudinal section
of a tube-making machine, illustrating another modification of the invention
and also illustrating a current-generating plant and circuit connections. Fig. 12
is a section, partly in plan, of a modified form of tube-forming dic. Fig. 13 is
a plan view of a modified form of mandrel. Fig. 14 is an end view of a pair
of compressing-rolls such as shown in Fig. 12 and which may replace certain
of the structures shown in other of the figures.
Fig. 15 is a longitudinal elevation, partly in section, of a further modification
of my invention, illustrating a portion of a tube making and finishing machine
showing the arrangement used by me for heating the tube while in process of
formation or completion, to the requisite temperature for electric welding, brazing
or annealing by heat radiated upon the same from one or more electric radiators
having a highly incandescent surface or surfaces. Fig. 16 is a longitudinal
section of one type of my electric radiator or furnace illustrating the position
of the tube, and likewise showing a generating source, electrodes and the circuit
connections therefor. Fig. 17 is a sectional end elevation on a larger scale,
of my improved radiating furnace shown in Fig. 16, with its cover or hood in
place. Fig. 18 a detail view of a hollow mandrel and internal electric radiator
supported thereby within the tube immediately over the meeting edges thereof,
above the external radiator, and the circuit connections for the same. Fig. 19
is a longitudinal section, and Fig. 20 a detail end view of a novel and simple
modification of my invention, in which the tube is indirectly but uniformly
heated by means of induced currents set up therein, the circuit connections in
Fig. 19 being shown diagramatically.
Referring to the drawings, and more particularly to Figs. 1 and 5, there is
shown a strip or web 1, which when passed through a suitable die 2 and at the
same time around a cylindrical mandrel 3 is formed into a tube 4. The die 2
(see also Fig. 4) is a cylindrical casting with a central passage 5 and having,
preferably, an internal chamber 6. The passage 5 is of such shape that it will
cause the web 1 to roll up into a tube on the mandrel 3, as in ordinary tube-
machines. The passage 5 has a flaring mouth, as shown, to facilitate the forma-
tion of the web into a tube, and it also flares slightly at the other end as
shown.
:
The chamber is provided with an inlet connected through a valve 7 to a

page_text: pipe 8, and it also has an outlet-opening 9, which it will be understood, is
connected to a suitable pipe. (Not shown.) The chamber 6 is provided for the
introduction into the die of a cooling fluid, for, as will presently be seen, the
die is subjected in some of the processes about to be described to a sufficient
degree of heating to make the use of some cooling agent advisable. As the
web passes to the die and is shaped thereby from a flat condition into a tube
the edges approach each other until when the mouth of the die is reached they
are in close relation, but still out of contact, and when the point of least
diameter of the die is reached they are pressed thereby into firm contact. Just
before the two edges are brought into contact in the arrangement of apparatus
now under consideration I heat them until they are raised to a welding tem-
perature, and before these edges can cool they are forced together by the die
and are welded. It will of course be understood that the width of the web and
the smallest diameter of the die are so proportioned that the heated edges of
the web will be upset into each other until the metal of the two edges coalesces
and thereby forms the weld in the now well-known manner.
In order to pro-
gressively heat the edges of the web preparatory to welding them, I utilize the
heating effect of the electric current, and for this purpose in the apparatus now
under consideration I use a carbon or other conducting pencil 10, mounted in
a suitable holder 11 and conducted by a conductor 12 to a suitable source 121 of
current-supply, which may be a secondary battery, a straight-current dynamo,
or any other suitable current source. The die 2 is also connected by a conductor 13
with the source of current-supply. When the leading end of the web has been
introduced into the die far enough to bring the two edges closer together and
just before they are forced into contact, the carbon pencil 10 is adjusted, so as
to be in contact with these two edges. A circuit will thus be established from
the source 12-of-current-supply by the conductor 13 through the die to the
two edges of the web, from thence to the carbon pencil 10, and by the conductor 12
back to the source 121 of current-supply. Now by moving the carbon pencil 10,
a short distance away from the juxtaposed edges of the web an arc will be
established, which will play between the carbon pencil and the said edges. As
is well known, the temperature of the arc is very high, and consequently the
two edges of the web are quickly brought to the welding temperature, and as
the web passes into the die to the point of least diameter these edges are forced
together and welded, as before stated. As the web passes into the die the
heated edges are prevented from collapsing by the mandrel 3, which is of the
same diameter as the internal diameter of the tube when formed, and is in this
instance made of refractory material.
In order to prevent the heated and therefore softened metal of the tube from
being dragged and torn during the passage through the die, I may cut away or
groove the die, as shown at 14 in Figs. 1, 4, and 10, so that the heated edges
before welding and the beaded seam or joint after welding do not come into
such contact with the die as to be damaged. With the means of quickly heating
the edges of the web to the welding temperature afforded by the electric arc,
the manufacture of tubing from a web with the seam welded may be quickly
and progressively accomplished.
In Fig. 1 I have shown a complete tube-making machine embodying my
invention, but with the mandrel-support and web-holding reel or support
omitted.
.
$
The die 2 is mounted in a suitable seat formed in a head 15 on the upper end
of a standard 16. The die may either be tapered on its outer surface and remov-
ably held in a correspondingly-tapered seat in the head 15 or it may be per-
manently held in its seat by means of an annular rib 17 on the die entering
a corresponding groove in the head 15. Secured to this head 15 is a binding
post 18, receiving the conductor 13, and rising but insulated from the head 15
there is a short standard 19, to which is pivoted one end of a lever 20, terminating
in a handle 21. The lever 20 carries a binding-post 22, receiving the conductor 12,

page_text: and also carries the carbonholder 11, with its carbon pencil 10. By means of
this lever 20 the carbon pencil 10 can be readily manipulated by an attendant
in the manner before stated to produce the arc. On account of the heat and
brilliancy of the arc a shield 23, of transparent refractory material, such as
mica, and tinted a suitable color, say blue, is fastened to the lever 20 between
the carbon-holder 11 and the handle 21 in order to protect the attendant. The
upper wall of the mouth of the die is cut away, as shown at 24, (see Figs. 1 and 4,)
to permit the carbon pencil 10 to be brought as close to the point where the
two edges of the web are forced into contact as possible. The web is drawn
through the die by means of mechanism which I will now describe with
reference to Fig. 1.
A clamp 25, shaped to grasp the completed tube after it has left the die, is
formed upon the upper end of a carrier 26, which latter has at its lower end a
roller 27, resting upon the floor or on a base-plate to which the standard 16 may
be secured. Below the clamp this carrier is traversed by a screw-threaded rod
or feed-screw 28, supported at one end by the head 15, through which it is
passed and in which it, is journaled as shown, and at the other end by a
journal bearing, as shown, in the upper end of a post 29, secured to the floor
or base-plate on which the machine rests. It will be understood that where
the feed-screw 28 passes through the carrier 26, the latter is screw-threaded, so
that when the feed-screw is turned in its bearing the carrier will be moved from
or toward the standard 16, as the case may be. In order to rotate the feed-
screw 28, it is extended beyond the head 15, and is there provided with a handle-
wheel 30, within reach of the attendant operating the machine, or, as is evident,
this feed-screw may be rotated by power. The lower end of the carrier 26, is
guided by a rod 31, passing through the carrier and supported at the ends in
the standard 16 and post 29, respectively. By turning the hand-wheel 30 with
the proper speed after the clamp 25 has been secured to the tubing that has
been formed by the die the web will be drawn through the die at a steady rate
and with comparative rapidity. At the same time, the arc is established and
the meeting edges of the web are progressively. welded together at the same
steady and rapid rate. It will be evident that instead of using a revolving feed-
screw mechanism for moving the clamp 25, I may use hydraulic power or any
other well-known or desirable form of draw-bench mechanism for imparting the
desired uniform speed to the clamp or carrier. When the carrier has reached
the limit of its travel, the electric circuit is interrupted to break the arc, and
the clamp 25 is loosened. The carrier is then returned to its first position and
the tube again clamped, after which the arc is again established and the manu-
facture of the tubing progresses as before. It will thus be seen that the length
of the tubing thus manufactured is only limited by the length of the web. The
die is of course subjected to heat radiated from the arc and to heating by contact
with the heated metal of the web. It would therefore in a short time become
unduly heated were it not for the fact that provision is made for the cooling
of the same. This I do by means of a cooling agent introduced into the chamber 6,
as before described. Instead of heating the edges of the web at the mouth of
the die it may be rolled up into the form of a tube and the seam heated and
welded after its passage through the die. This method is preferred by me particu-
larly in the case of tubes formed from the thinner gauges of metal. Means for this
purpose are shown in Figs. 2 and 3. The die 2 and head 15 are practically
the same as shown in Fig. 1. The lever 20 is mounted at the rear of the head 15
instead of at the front, so that the arc is established between the carbon
pencil 10 and the edges of the seam in the tube after the latter has left the
die. In order to force the heated edges of the tube together and thus complete
the weld, I sometimes provide a clamp, which may be termed a welding
clamp," composed of two jaws 32, 33, hinged together at one end, and shaped
to grasp the tube at the other end. These jaws are adjusted to grasp the tube
with any desired pressure by means of a rod 34, terminating at one end in a
hand-wheel 35 and at the other in a head 36. A portion of the rod is threaded

page_text: and passes through a nut formed in the jaw 33, while the smooth portion of
the rod passes freely through the jaw 32. A spring 37 is placed on the rod 34
between the head 36 and jaw 32. By this means the jaws are made to grasp the
tube with a pressure tending to force the two edges together and will auto-
matically effect the welding of these edges when they are heated. The welding
pressure clamp just described is employed by me in cases where the tubes to
be formed are made of comparatively soft or ductile metal, such as brass or
copper, or of highly annealed iron or steel in which the degree of hardening
produced by the passage of the web through the forming-die is insufficient to
produce a spring-pressure between the meeting edges of the tube under forma-
tion. When my process is applied to the manufacture of thin-walled smooth
steel tubing, however, such as I propose to use for bicycle-frames, interior
electric-wire conduits, etc., to which my improved process is especially appli-
cable with great economy and other advantages over existing methods, I prefer
to so proportion the die 2 and the mandrel 3 as to form the tube with the edges
pressed together with considerable force at and beyond the point where it
emerges from the die, this pressure being sufficient to cause the edges of the
tube to be welded together when suitably heated-as, for instance, in the
manner described with reference to Fig. 2-that is to say, the seam is heated
after the web has passed through the die. In such cases the tube undergoes a
slight drawing operation and receives a certain spring tension (due to its crowd-
ing between the forming mandrel and die) sufficient to produce the requisite
welding pressure, so that the welding-clamp may be dispensed with. I may
replace the welding-clamp shown in Figs. 2 and 3 by die 21, (shown in Fig. 2,)
which die will be placed as close to the pencil 10 as possible and will be of such
diameter as to slightly reduce the tube formed by the die 2, in order to effect
the welding and finishing of the joint.
a
My invention is not limited to the use of an arc established between
carbon pencil and the two edges to be welded, as shown in Figs. 1, 2 and 5, for
these edges may be heated by an are formed between two adjacent carbon
pencils. Such an arrangement is shown in Fig. 6, where the arc is established
between two carbon pencils 10, 10, both mounted in a common holder 11', which
if desired, may be carried by or form part of the lever 20, shown in Fig. 1.
It will be understood that suitable means for adjusting the carbon pencils 10 10
relative to each other will be provided but such means form no part of the
present invention and are omitted from the drawings.
One
My invention may also be practiced by heating the edges to be welded by
the heating effect of a suitable electric current passed directly through them
when they are arranged to bridge the terminals of the electric circuit.
means for this purpose is shown in Figs. 7, 8 and 9. The die 2 in this structure'
is composed of an outer shell 38 and an inner shell 39, the two shells being
separated by interposed refractory insulating material 40. The shell 38 is
formed with an inwardly-projecting rib 41, extending through but insulated
from the shell 39, as shown in Fig. 9. This rib 41 may be shorter than the
shell, or, as indicated in Fig. 7, it may be as long as the shell. The inner end
of the rib 41 conforms to or may project slightly beyond the inner face of the
sheil 39, and it is so located that as the web passes through the die the inner
end of the rib makes contact with the two edges to be welded, the binding
post 18 receiving the conductor 13, secured to the outer shell 38. Consequently
the current can pass from this shell to the web only through the rib 41. The
other terminal of the electric circuit is formed by the mandrel 3, which in this
instance is of material made hollow and is provided with inlet and escape
pipes 42 43 for the circulation in the mandrel of a cooling fluid. Where the
mandrel is touched by the web as the latter is curled up into the form of a
tube, it is reduced in diameter, as shown at 44, and covered with a jacket 45
of refractory insulating material the thickness of which is such that the normal
diameter of the mandrel is restored. On the top of the mandrel at a point

page_text: just back of the insulating-jacket 45 and close to where the two edges to be
welded come into contact with the rib 41, there is a projection or boss 40, 80
formed as to make contact with both of the edges to be welded as they enter
the mouth of the die. The mandrel 3 being connected, as at 47, with the
conductor 12, the circuit is established between the rib 41 and mandrel by way
of that portion of the metal of the web which lies between the said rib 41 and
boss 46, and the current being suited for the purpose the metal immediately
adjacent to these two edges and included between these two contacts will be
quickly raised to a welding temperature. In this structure, as well as in the
structures shown in the previous figures, the web after being heated is further
reduced in diameter, so that the heated edges are forced together and welded.
The
In Fig. 11 I have shown another means whereby the heating of the web by
the passage therethrough of the electric current may be effected. In this case,
the same as in the structure shown in Fig. 2, I use a forming-die and a reducing-
die 2. The forming-die 2 is of such diameter as to bring the meeting edges
of the web firmly together, while the die 21 is so proportioned as to still further,
though slightly, reduce the diameter of the tube formed by the die 2.
binding-post 18 is on the die 2 and receives the conductor 13, and the binding-
post 22 is on the die 21 and receives the conductor 12. The mandrel 3 is
covered with insulating material, as in Figs. 7, 8, and 9, where it enters the
die 2. The circuit between the two dies is completed by the intervening length
of the tubing, and this is quickly heated by the current. Experience has shown
that under such circumstances when the meeting edges are raised to the weld-
ing temperature the rest of the tube is considerably cooler, and will therefore
resist the strain as the tube passes through the die 21. These edges will be
forced together and welded. The dies 2 and 2' may of course be constructed
like that shown in Figs. and 9.
i
In Fig. 11 I have also shown a well-known means for generating currents
of the requisite heating effect adapted to the method of tube manufacture set
forth with reference to Figs. 7 and 11. The two conductors 12 13 are con-
nected, respectively, to the terminals of the thick wire coil 48 of a converter 49.
The thin-wire coil 50 of this converter is connected on one side by a conductor 51
to one terminal of an alternating-current generator 52 and on the other side
by a conductor 53 to a reaction-coil 54. The other terminal of the generator 52
is connected by a conductor 55 to a switch 56, capable of including more or
less of the reaction-coil in the circuit for regulating the current-supply. The
generator 52 may be located at a distant station, in which case the conductors 51
and 55 would represent the mains, and it would then supply currents of com-
paratively high tension. With such a generator I obtain the low-tension
currents best adapted for welding in the manner set forth with reference to
Figs. 7 and 11 by means of the converter 49, designed for this purpose. It
will be understood of course, that the generator 52 may be so constructed as
to supply directly the low-tension currents adapted to the practice of my inven-
tion as set forth with reference to Figs. 7 and 11. It will also be understood
that in the practice of my invention, whether I use the heat of the electric arc
or heat the web directly, I am in no wise limited to any specific source of
current-supply, since I may use any source of current adapted to the purpose
of my invention.
In Figs. 12 and 14 I have shown a die in which the web is bent into the
form of a tube partly by the body of the die and partly by forming-rolls between
which the web, already partly completed by the body of the die, is drawn to
force the edges constituting the seam into contact. In this instance the meeting-
edges of the web are heated just in advance of the rolls, so that the said edges
are welded together on passing between these rolls. In the structure shown
in these Figs. 12 and 14 the die 2 has a flaring mouth and contracted throat,
as in the other figures of the drawings. At the rear end of the die there are
journaled two rollers 57, 57, each with a semicircular groove 58 in its peri-

page_text: phery. These rollers are so arranged that the tube formed by the die will pass
between them and be somewhat reduced in size thereby. In this structure the
meeting edges of the web are heated by an electric arc as in Fig. 1, just before
the rollers 57 are reached. The slight reduction of the diameter of the tube
due to the rollers 57 is sufficient to cause the welding of the heated edges of
the tube. It will be understood, of course, that I may use reducing-rollers in
place of the die for forming the web into a tube, or I may replace the welding-
clamp (shown in Figs. 2 and 3) or the die 21 (shown in Figs. 2 and 11) with
rollers having the same function.
In those structures embodying my invention wherein the meeting edges of
the web are heated before they are brought into contact I may form the mandrel,
as shown in Fig. 13, so as to prevent the heated and softened metal from being
dragged and torn by contact therewith. For this purpose I form the mandrel
with a globular head 59, in which is journaled a roller 60, with its periphery
flush with the surface of the head 59. This roller 60 is arranged to rotate in
the direction of the line of travel of the web and in contact with the meeting
edges of the said web, so that these edges when heated are not dragged or torn
on passing over the mandrel.
When the forming die 2 (or, if preferred, the mandrel 3,) is provided with a
groove or depression, 14, as shown with respect to the die illustrated in Figs. 1,
4 and 10, where the web is heated in advance of the die, the joint of the tube
will be formed with a slight reinforcement, as shown in Fig. 10, which adds to
its strength at the seam. In cases where such reinforcement in the finished
tube is not desirable, I flatten the same either by a gradual contraction of the
groove, 14, of the die, 2, to the normal diameter of the latter, at the point where
the tube emerges from it, or by a subsequent drawing or finishing operation,
with or without electrically reheating the tube or the seam thereof, according
to the character and condition of the metal of which the tube is composed and
the thickness and diameter of the same. In either case, the reduction or elimina-
tion of the ridge, as described, serves to further condense the metal and to
increase the strength of the joint.
When my invention is applied to the manufacture of tubes formed from very
thin webs of metal, such as tubes intended for bicycle frames, interior electric
wire ducts, gas pipes, rain-spouting, stove pipes, etc., etc., I prefer to employ as
the proximate source of heat, a resisting conductor or mass of resisting conduct-
ing material that is heated to intense incandescence by the passage therethrough
of an electric current or currents. The incandescent body or surface is of elongated
form and is adjustably or removably secured to the draw-bench at or near the
point where the tube emerges from the forming die, the heat from the incan-
descent surface or surfaces being radiated upon the tube along the line of its
abutting edges or joint, and being regulated in intensity so as to raise the
abutting edges to the necessary temperature for welding, brazing or otherwise
uniting the same. This is illustrated in Figs. 15, 16, and 17, which show the
tube subjected along the line of its seam to the radiation of heat from one or
more of my electric radiators or furnaces.
As will be seen by reference to Fig. 15, the web in this instance is preferably
fed into the die 2 from a reel or table (not shown) located at a point above the
mandrel 3, so that the abutting or overlapping edges or scam is at the lowest
portion of the tube 4, as the latter emerges from the die. The incandescent
conductor or material consists of a mass of granulated carbon, 61, or other suit-
able semi-conducting body, (see Figs. 16 and 17,) enclosed within one or more
small elongated chambers, 62, formed of refractory insulating material, such as
chalk, fire-brick or the like, containing electrodes, 63, 64, provided with ter-
minals, 63, 64, respectively, to which are attached the conductors, 65, 66, from
a source of heating current, 67. An adjustable rheostat or current regulator, 68,
is included in the circuit. By means of the regulator 68, the current passing
through the incandescing conducting material may be controlled, and consequently

page_text: the degree of heat radiated, which may thus be accurately adjusted to suit the
nature and thickness of the metal of which the web is composed and the speed
at which it travels through the dic 2. The radiator is open at its central upper
portion, where it is slightly contracted and provided with curved lips, 69, 69,
which embrace the lower portion of the tube, 4, at either side of the meeting
edges. It will thus be observed that the tube itself, as it is drawn through the
die by the traveller of the draw bench, constitutes the cover for the radiating
chamber.
The radiator 62, as more clearly shown in Fig. 17, is provided with a cover
or hood, 70, also of refractory or non-conducting material designed to prevent
the escape of heat from the upper portion of the radiator. This cover is provided
with a knob, 71 by which it may be removed, and has end openings, 72, to admit
of the free passage of the tube, 4, through the same. The hood, 70, which also
serves as a screen when the radiator slot is exposed, is not absolutely essential,
to the proper operation of the furnace, and for some classes of work may be dis-
pensed with. It will be understood that the curvature of the lips 69, as well
as the size of the opening 72, in the hood, where it is used, will be adapted to
the size or diameter of the tube that is being made. The electrodes 63 and 64,
which are preferably of carbon, are inserted through suitable openings at
opposite ends or sides of the radiator, 62, and are capable of adjustment within
the same, so that they may be brought together for the purpose of forming an
arc prior to the heating of the conducting mass 61, as shown in dotted lines in
Fig. 16, in which the electrodes are shown as passing through the ends of the
radiator.
!
In Fig. 15 are shown two radiators 62, 621, having multiple electrodes extend-
ing through opposite sides of the radiators instead of through the ends. These
radiators are preferably placed upon a table or platform, 73, that is mounted
in slides or ways upon the standard 16, of the draw-bench. The table, 73, is
vertically adjustable by means of a rack, 74, and pinion 75, operated by hand-
wheel 76, conveniently mounted in the standard 16. By operating the hand-
wheel 76, the table 73 with its radiators 62 and 621 can be dropped out of the
way when it becomes necessary to start the end of a new web through the
forming die 2, and again raised into position against the lower edge of the tube
when a sufficient length of the latter has been drawn out by the traveling clamp
(not shown,) forming part of the drawbench mechanism. To the upper end
of the head 15, containing the die 2, which latter is shown resting within a
taper seat, is preferably secured an automatic circuit-breaking device, 77, of
any suitable construction, so arranged as to normally maintain the continuity
of the circuit through the radiators at the contacts 78 while the web 1 is passing
through the die 2, but to automatically break this circuit when the rear end of
the web has passed through the die and thereby interrupt the flow of heating
current through the radiators 62 and 621. The same result may also be manually
obtained by manipulating the regulator switch 68. Where an automatic circuit
breaker is used, however, I may sometimes provide a shunt resistance, 79, so
as to minimize the sparkling at the switch contacts and to prevent the entire
cooling of the incandescent mass 61 when the main current is broken. Instead
of the primary or secondary battery shown diagramatically at 67, any other source
of current adapted to the work in hand may be used, and any desirable method
of current-control may be employed.
A single radiator will ordinarily be sufficient for each drawbench, but in case
of a high rate of web speed two radiators in tandem, as shown in Fig. 15, are
desirable, the first radiator 62, serving to preliminarily heat the traveling abut-
ting edges up to a temperature somewhat less than that required for welding
or brazing, while the second radiator 62 imparts the final heat to effect the
complete union of the contacting edges. In this case the radiators are placed end
to end so that the heated tube passes directly from one into the other without
exposure to the atmosphere. The radiator 621 may, however be independently

page_text: used for the purpose of annealing the entire body of the tube, 4, after the same
has been welded in passing through the first radiator, 62. In this event, the
radiator 621 is separated from radiator 62, and is constructed without the con-
tracting lips, 69, 69, so as to radiate a lower degree of heat upon the entire
surface of the tube, and is brought to a point near the reducing or finishing
die, 21, mounted in the standard 16. The two processes of welding and annealing.
may be combined in a single operation, as shown in this figure, or they may
be separated and carried on independently, according to the class of work to
be done.
In some cases, as shown in Fig. 18, I may supplement the external radiator, 62,
with an internal radiator, 80, that forms a projection of or is removably attached
to the head of a hollow forming-mandrel, 3, so as to project for a short distance
into the interior of the tube 4, at a point directly over or in alignment with the
external radiator, so that both the inner and outer surfaces of the seam may be
simultaneously heated. The inner radiator, 80, may be supplied either from the
same or a separate source of current 67, and is capable of regulation by the
regulator 68, the leading wires, 65, 66, being introduced through the free
end of the hollow mandrel as shown.
The incandescent surfaces of my electric radiator or radiators, as will be seen,
are brought as closely as practicable to the moving seam and within effective
heat-radiating proximity to the latter without actually touching the tube, while
the refractory non-conducting walls of the external radiators, effectually pre-
vent the appreciable escape or radiation of heat to the surrounding atmosphere,
or to the main body of the tube, and at the same time prevent any access of
the atmosphere to the edges of the metal being heated. The electrical heat
thus produced, is in its purest state, since no oxidation can take place, and there
are no products of combustion. to interfere with the production of a perfect
weld.. The progressive movement of the tube, combined with the elongated
shape of the radiating surface, insures a gradual increment of heat being
imparted to the same, up to the maximum uniting temperature, without heating
or injuring the thin metal of the web, and without the deposit in the joint of
any foreign matter, such as would otherwise interfere with the production of
a perfect union.
I have found that, except in the case of very thick walled tubes, the meeting
edges may be heated and welded by my process so effectively and rapidly that
the body of the tube, up to within a very short distance of the line of the joint,
remains practically cold, thereby not only permitting the welding of the joint
through the uniform pressure exerted upon it by the main body of the tube,
as already explained, but enabling me to produce such weld progressively during
the shaping and drawing process without unduly drawing or extending the
metal of the tube as would be the case if the entire body of the tube were heated,
as practiced prior to my invention, and, as before stated, with greater economy
in the expenditure of energy for heating purposes.
Although I have herein more particularly referred to one feature of my
process which embodies the simultaneous forming and welding of the tube, I do
not desire to be limited to this mode of practicing my invention, since it will
be obvious that I may first form the tubes from suitable webs or strips of the
proper width either by drawing or rolling and with either straight or spiral
seams, and with butt or lapping joints, and then weld the seam electrically by
any one or more of the methods described, as a subsequent and independent
operation. The particular mode of procedure selected by me will necessarily
depend largely upon the nature and character of the tubes to be produced and
the service for which they are to be employed.
I have found that where light gauge tubes made by my improved process
require to be reheated or annealed either for the purpose of further reducing
or redrawing them or for other reasons, that my process of heating progressive
sections of the tube. electrically possesses numerous advantages, inasmuch as

page_text: they may be perfectly annealed or reheated to any desired temperature, without
recourse to expensive and time-consuming annealing furnaces, while they are
being fed into the reducing die. For this purpose, as explained in connection
with Fig. 15, I make use of a modification of my electric radiating furnace which
is constructed so as to admit of the passage of the tube therethrough imme-
diately in advance of the reducing die or other device into which the annealed
tubes are to be fed.
In Fig. 19, I have illustrated a modification of my radiation method of heating
tubes for welding, annealing and other purposes, whereby the same are heated
to the required degree, without being brought into direct contact with electric
terminals or with the source of heating current. In this method, which I have
found particularly well adapted for small, thin-walled tubes, the heat is generated
in the tube itself by electro-magnetic induction. By referring to Fig. 19, it
will be seen that that portion of the tube 4, that is to be heated, constitutes the
moving secondary circuit of an induction coil 81, whose stationary primary
winding 82, is in inductive relation therewith and is surrounded by a suitable
magnetic shield or envelop to enclose and concentrate the lines of force. This
shield or envelop consists, preferably, of two concentric soft iron heads, 83, 83,
having radial slots in their periphery as shown more clearly in the detail view,
Fig. 20, within which slots are seated the ends of soft-iron bars, 84, whose
laminations run in a direction parallel with the axis of the tube and which
serve to magnetically connect the heads 83, 83, thus forming a kind of magnetic
cage or circuit around the inducing coil 82 and that portion of the tube 4
lying within the same. The inducing coil 82 and the heads 83, 83, are mounted
upon a sleeve S5, of asbestos or other refractory, non-conducting material, some-
what larger in diameter than the tube to be heated, which latter is thus permitted
to pass through the same in close inductive proximity to the inducing coil 82.
The ends of the primary coil are shown connected to the secondary winding, 48,
of a transformer 49, whose primary winding 50 is fed from a generator, 52, of
alternating electric currents, as in Fig. 11. The terminals of the inducing coil 82
may, however, be directly connected across the leads of an alternating current
circuit or to the generator 52 without the interposition of the transformer 49.
A reactive coil, 54, or other variable current controlling device is included in
the circuit of the inducing coil 82, to permit of controlling the working tempera-
ture, as by the manipulation of a switch lever 56¹, in accordance with the
particular class of work and the size and speed of the tube, and to permit of
maintaining the same at any desired degree. A suitable current regulator, 56,
may be employed in the circuit of generator 52, in lieu of or in addition to the
reaction coil 54. When an alternating current of small volume and high tension
is passed through the inducing coil 82, it will generate induced alternating
heating, currents of large volume and low pressure in the tube 4, by which
the tube will be annealed to any desired extent as it travels through the
sleeve 85, preparatory to entering the reducing or finishing die 21, illustrated in
Fig. 15.
I may also use this novel method and apparatus as a substitute for those here-
in before described, for the purpose of welding or otherwise uniting the seam
of the tube by electric currents generated therein inductively. It will, in this
connection, be evident to those skilled in the art that the tubular web formed by
the die and mandrel has a higher electrical resistance along the line of its
abutting edges than at any other portion of the section that is under the induc-
tive influence of the primary coil, so that the current induced therein would
develop the greatest heat along the line of the joint. The initial heat thus
generated serves to still further increase the electrical resistance of, and con-
sequently, the degree of heat developed at, the joint, so that by the time the
tube has passed through the inducing coil, in a properly organized apparatus,
the abutting edges will have been heated sufficiently to unite and form the
weld under the spring pressure originally imparted to the tube by the mandrel

page_text: and die, and before the main body of the tube has become appreciably or unduly,
heated. In practising my method I confine the induced currents to the section
of the tube immediately embraced by, or within the field of, the inducing coil,
by means of electro-magnets, 86, 86, or in lieu thereof, by suitable counter-
electro-motive-force coils, 87, (whose terminals 88, 881, are in connection with
a suitable source of current, not shown,) that are placed around the tube at
either end of the main inducing coil and operate to confine the development
and flow of heating current to the section of the tube being heated.
It will be apparent that the employment of radiant energy as above described,
whether in the form of electro-magnetic induction or of heat radiation, for the
purpose of indirectly heating tubing, without the direct application thereto or
contact therewith of the primary source of heat or of products of combustion
possesses numerous and decided advantages over those forms of my apparatus
in which an electric arc is projected against the tube, or in which the tube itself
forms part of an external heating circuit or constitutes one of the terminals
thereof. Chief among these advantages are the increased cleanliness and perfect
nature of the heat produced, its absolute localization and control, its uniformity,
rapidity and economy, its non-injurious character, its applicability to tubes
of thinner gauge than can be otherwise safely heated and the perfection of and
freedom from foreign matter in the weld, by which welded tubes in all respects
the equal of seamless drawn tubes can be rapidly and economically made.
It will also be evident that my improved method and apparatus shown in
Fig. 19 and 20 as applied to the manufacture of tubes, may also be readily aud
advantageously applied to the general heating of metals inductively, for other
than tube manufacturing purposes, that is to say, for general annealing, welding,
brazing, soldering and other industrial uses or metal-working operations, to
many of which I have already applied it with success. I desire it understood,
however, that it is not intended to broadly claim herein such general applica-
tions of my improved method and apparatus for heating metals inductively, to
other than tube manufacturing purposes, since the same is herein expressly
reserved by me and will be made the subject-matter of separate applications
for Letters Patent.
While I have heretofore mentioned various methods of locally applying or
developing the desired heat in my improved process of tube manufacture, I
am not necessarily limited to the employment of electrically developed heat
in all cases, for the reason that when tubing is made from the web by the
passage of such web through my improved mandrel and forming die which
imparts to the tube the quality of self-contained spring pressure tending to firmly
close or press together the previously trimmed abutting edges of the web or
tube, I find that the joint thus formed may be successfully heated to the welding
temperature by any ordinary source of heat, such as a gas or oil flame, without
danger of oxidizing the abutting edges or of depositing foreign matter upon
the same to an extent that would otherwise interfere with their perfect union.
Furthermore, while I have described my process as applied to the manufacture
of tubes from webs in which the webs are moved and in which the heating
devices are stationary, I do not desire to be understood as limiting myself to
such mode, as the novel features of my process may in many cases be applied
with equal advantage to the seaming or welding of tubes or pipes in which the
latter are stationary and in which my various heating devices form the portable
or movable element, without departing from the scope or spirit of my invention.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The herein described improvements in methods of and apparatus for manu-
facturing tubes and pipes, substantially as specified.
2. The herein described improvements in methods of and apparatus for con-

page_text: verting web or strips of metal into tubes and pipes and for uniting the meeting
edges of the same, substantially as specified.
3. The herein described improved methods of and apparatus for employing
the heating effect of an electrical current or currents in seaming or welding
a progressively moving metal tube or pipe, substantially as specified.
4. The herein described methods of and apparatus for heating metallic tube
or pipe for welding, brazing, soldering or annealing operations by means of
radiant energy developed in a medium separate from said tube or pipe but within
effective radiating proximity thereto, substantially as described.
5. The herein described improved methods of and apparatus for indirectly heat-
ing metallic tube or pipe through the action of an electric current or currents
flowing in a conductor or conducting medium adjacent thereto and out of contact
therewith, substantially as and for the purposes specified.
6. The method of manufacturing tubing from webs of metals, which consists
in shaping the web into a tube with its meeting edges pressed against each
other while the web is in a cold or practically cold condition and then welding
the meeting edges together, substantially as described.
7. The method of manufacturing tubing from webs of metal which consists
in passing the web without preliminary heating, or in a cold state, through a
forming die, and simultaneously therewith heating the meeting edges thereof
to a welding temperature and welding the same, substantially as described.
8. The method of manufacturing tubing from webs of metal which consists
in passing the web through a forming die and simultaneously therewith heating
the meeting edges to a welding temperature by the heating effect of an electric
current and welding the said meeting edges, substantially as described.
9. The method of manufacturing tubes from webs of metal, which consists
in progressively forming the web into a tube, pressing the meeting edges of the
web into contact and then heating the contacting edges along the line of the
joint to be formed to the temperature requisite to effect the desired union, sub-
stantially as described.
!
10. The method of manufacturing seamless tubes from webs of metal, which
consists in progressively forming the web into a tube, pressing the meeting
edges of the web into contact, and then heating the said edges to a welding
temperature and causing them to unite, substantially as described.
11. The method of manufacturing tubing from webs of metal, which consists
in progressively forming the web into a tube; progressively raising the meeting
edges to a welding temperature by the heating effect of an electric current, and
then forcing the same together, substantially as described.
12. The method of manufacturing tubing from webs of metal, which consists
in shaping or forming the web into a tube with the meeting edges abutting,
condensing the metal of said tube concurrently with such shaping or forming
process so as to produce in the same a spring-pressure tending to force the
abutting edges firmly together, and in heating the abutting edges while under
such pressure to a temperature suitable for welding or otherwise uniting the
same, substantially as described.
:
13. The method of manufacturing tubing from webs of metal, which consists
in progressively folding the web into a tube, with the meeting edges in abutment
and sprung together by the resiliency of the metal of the web, and progressively
heating the contacting edges to a welding temperature, whereby the said edges
are upset and welded by the spring of the tube, substantially as described.
14. The method of manufacturing tubing from webs of metal, which consists
in shaping the web into approximately tubular form while the same is cold
or practically cold, drawing or compressing the metal of said tube so as to impart
thereto a spring-pressure tending to force together the opposing or abutting
edges of the same, heating the said edges to a welding or brazing temperature
without destroying the tension or appreciably drawing the temper of the main
body of said tube, and in completing the welding or union of the said edges

page_text: while so heated by virtue of the spring pressure or tension imparted to the walls
of said tube during the drawing or compressing operation, substantially as
described.
15. The method of manufacturing tubes from webs of metal, which consists
in progressively folding the web into a tube with its meeting edges in abutment
and under pressure, progressively heating the contacting, edges to a welding
or brazing temperature while under such pressure, so as to cause the same to
coalesce or unite, and redrawing the tube thus formed for finishing, substan-
tially as described.
16. The method of manufacturing seamless tubes from webs of metal, which
consists in progressively folding the web into a tube, with the meeting edges
in abutment and sprung together by the resiliency of the metal of the web,
progressively heating the contacting edges to a welding temperature, whereby
said edges are upset and welded by the spring of the tube, and redrawing the
said welded tube for finishing, substantially as described.
17. The method of manufacturing tubing from webs of metal, which consists
in folding the web into a tube with its meeting edges pressed together, and
in heating said meeting edges by radiant energy to a temperature suitable for
brazing, welding or otherwise uniting the same, substantially as described.
18. The method of manufacturing tubing from webs of metal, which consists
in folding the web into a tube, and in heating said tube to a temperature suit-
able for brazing, welding, annealing or otherwise working the same by means
of heat directly or indirectly developed therein from an independent source
of radiant energy located in operative proximity thereto, substantially as
described.
19. The method of manufacturing tubing from webs of metal, which consists
in passing the web through tube-forming dies or rolls so as to-shape the same
into a tube, with its edges in abutment or slightly overlapping and in subjecting
the tube contemporaneously with its passage through the forming dies or rolls
to the heating effect of an independent source of radiant energy, whereby a
brazed or welded union is effected between said edges, substantially as described.
20. The method of manufacturing tubing from webs of metal, which consists
in folding the web into a tube with the meeting edges pressed together, and
in heating said meeting edges to a temperature suitable for brazing, welding
or otherwise uniting the same, by means of heat radiated from an incandescent
body or surface in proximity thereto but out of contact therewith, substantially
as described.
21. The method of manufacturing tubing from webs of metal, which consists
in folding the web into a tube with the meeting edges pressed together, and
in heating said meeting edges to a temperature suitable for brazing, welding
or otherwise uniting the same, by means of heat radiated from one or more elec-
trically heated incandescent bodies or surfaces located in effective heat-radiating
proximity thereto but out of contact therewith, substantially as described.
22. The improved method of heating metal tubing preparatory to brazing,
welding, drawing, reducing or otherwise working the same, which consists in
subjecting the tube in whole or part to radiant energy from one or more
radiating bodies or incandescent surfaces, wholly or partially surrounding the
same, substantially as and for the purpose set forth.
23. The improved method of heating metal tubing preparatory to brazing
drawing, reducing or otherwise working the same, consisting in subjecting the
tube in whole or part to radiations from one or more electrically heated incan-
descent bodies or surfaces wholly or partially surrounding the same, and in
controlling the degree of heat developed in the tube to suit the requirements
of the desired operation by varying the intensity of incandescence of one or
more of said bodies or surfaces, substantially as described.
24. The improved method of seaming metal tubing which consists in passing
the tube with its meeting edges in abutment, over one or more electrically

page_text: heated incandescent bodies or surfaces, and in controlling or regulating the
radiation of heat upon said meeting edges by varying the degree of incan-
descence of said surfaces in accordance with the speed of travel of the tube,
substantially as described.
25. The improved method of and means for electrically heating or annealing
metal tubing, which consists in subjecting progressive portions of the tube to
be heated or annealed to the inductive influence of an alternating current or
currents flowing about the same, whereby the said tube, or successive portions
thereof, constitutes an induced circuit in which electric heating currents are
set up, substantially as and for the purposes described.
26. The improved method of and means for electrically heating metal tubing,
consisting in setting up induced heating currents in the said tube or successive
portions thereof, so as to flow in a direction at right angles to the axis of said
tube, and in localizing and confining said heating currents to the portion or
portions of the tube to be heated, substantially as and for the purpose set
forth.
27. The improved method of and means for electrically heating metal tubing
in the process of manufacturing the same, which consists in passing the metal
or blank of which the tube is made through suitable forming, shaping or
reducing dies or rolls, and in subjecting the same or a portion thereof to the
direct or indirect heating effect of an electric current or currents contempor-
aneously with the passage of the tube or blank through such forming, shaping
or reducing dies or rolls, substantially as and for the purpose or purposes
described.
28. The improved method of and means for electrically heating metal tubing
in the process of manufacturing the same, which consists in passing the metal
or blank of which the tube is made through suitable forming, shaping or
reducing dies or rolls, and in subjecting the same or a portion thereof, contem-
poraneously with its passage through such forming, shaping or reducing dies
or rolls, to the direct or indirect heating effect of an electric current or currents
while said tube or blank is protected against atmospheric oxidation, substan-
tially as described.
29. In an apparatus for making tubes from webs of metal, the combination
of a stationary mandrel, a tube forming and closing die surrounding the head
of the same, a traveling clamp or clutch for the tube, and means, substantially
such as described, for electrically heating the tube, along the line of the seam
formed by the passage of the web through the mandrel and die, to a welding
or brazing temperature, substantially as described.
30. In an apparatus for making tubes from webs of metal, the combination
of a stationary mandrel, a tube forming and closing die surrounding the head
of the same, a traveling clamp or clutch for the tube, and means, substantially
such as described, for electrically heating the tube along the line of the seam
formed by the meeting edges of the web to a temperature suitable for effecting
a union between the said meeting edges, substantially as described.
31. An apparatus for making tubes from webs of metal, comprising the com-
bination of a tube forming and closing die, a source of electric heating current
or currents one or more electrodes connected with said source and adapted to
be brought into operative proximity to the web or tube for heating the same,
and means, substantially as set forth, for imparting a progressive motion to
the said web or tube while the same is being heated, substantially as and for the
purpose or purposes described.
32. An apparatus for making tubes from traveling webs of metal, comprising
the combination of a stationary mandrel, a tube forming and closing die, a
source of electric heating current or currents, one or more electrodes con-
nected with the said source and adapted to be brought, either directly or
indirectly, into operative proximity with. respect to the edges or seam of the
traveling web or tube at or near its point of emergence from the closing-die,
and means substantially as described for imparting motion to the said web or

page_text: tube while the same is being traversed by, or otherwise subjected to the heating
effect of, the current or currents from said source, substantially as and for the
purpose described.
33. An apparatus for making tubes from traveling webs of metal, comprising
the combination of a tube-forming mandrel and die or its equivalent, a source
of electric current or currents, means, substantially such as described, adapted to
be brought into operative relation with respect to the tube or its seam at a
short distance from the forming-die, and designed and arranged to convert the
electrical energy of said current or currents or a portion thereof into heat energy
directed upon, or developed within, a given length of the tube or seam, and a
suitable clamp, clutch or rolls for progressively moving the web or tube and
thereby causing successive portions of the same to become heated, substantially
as described.
34. An apparatus for making tubes from webs of metal, comprising the com-
bination of a tube-forming die and feeding or drawing mechanism therefor
arranged to fold the web into a tube with its meeting edges in abutment or
slightly overlapping, means for imparting pressure to said meeting edges, and
an electric heating device for heating the contacting or meeting edges as they
issue from the forming-die to a welding temperature, whereby the same are
progressively welded and united, substantially as described.
35. An apparatus for making seamless tubes from webs or strips of metal,
comprising the combination of a tube forming die and feeding or drawing
mechanism therefor arranged to fold the web into a tube with its meeting
edges in contact and under pressure, an electric heating device for progres-
sively heating and welding the contacting edges as they issue from the forming-
die and a reducing or finishing die for condensing and finishing the joint
(and
thus formed, substantially as described.
36. An apparatus for manufacturing tubes from webs of metal, comprising
the combination of a forming-die arranged to fold the web into a tube so as
to spring the edges in abutment by the resiliency of the metal of the tube and
a heating device for heating the contacting edges to a welding temperature,
whereby the said edges are upset and welded by the spring of the tube, sub-
stantially as described.
:
37. An apparatus for manufacturing tubes from webs of metal, comprising
the combination of a forming-die arranged to fold the web into a tube so as
to spring the edges in abutment by the resiliency of the metal of the tube and
an electric heating device for heating the contacting edges to a welding tem-
perature whereby the said edges are upset and welded by the spring of the tube,
substantially as described.
38. In an apparatus for making tubes from webs of metal, the combination,
with the tube-forming die and the traveling web or skelp, of a source of electric
current for heating the said web or skelp, a traveling clamp or equivalent
feeding mechanism for moving the web or skelp through the forming-die at
a given speed or speeds, and an electric regulating or controlling device whereby
the degree of heat imparted to the web or skelp may be varied in accordance
with the speed of the traveling clamp or other feeding mechanism, substan-
tially as described.
39. In an apparatus for making tubes from webs of metal, the combination,
with the tube-forming die and the traveling web or skelp, of a source of electric
current for heating the said web or skelp, a traveling clamp or equivalent
feeding mechanism for moving the web or skelp through the forming die and
an electric regulating, shunting or circuit-breaking device controlled and
operated by the said web or skelp, substantially as and for the purpose
described.
40. In a tube-making apparatus, the combination, with the tube-forming
mechanism or draw-bench, of a source of electric current or currents for heating
the metal or blank from which the tube is formed, and means, controlled by the

page_text: movement of the said metal or blank, for regulating, interrupting or otherwise
controlling the flow of the heating current or currents substantially as described.
41. In an apparatus for making tubes from webs of metal, the combination,
with the stationary tube-forming die, of an electrode-holder mounted upon the
framework of said apparatus near said die, and having one or more electrodes in
connection with a suitable source of heating-current, said holder being adjustably
mounted so as to be moved to bring its electrode or electrodes into and out of
operative relation or proximity with respect to the tube formed by said apparatus,
substantially as described.
42. In a tube making apparatus, an electric heating device designed and
adapted to surround the tube or a portion thereof and to heat the same by
radiant energy.
43. In a tube making apparatus, an electric heating device arranged and
adapted to surround the tube or a portion thereof and to heat progressive portions
of the tube by radiant energy as the tube is passed through the same.
44. In a tube making apparatus, a heating device designed and adapted to
surround the tube or a portion thereof and to heat the same to the requisite work-
ing temperature by radiant energy, without accompanying products of combustion,
substantially as described.
45. In a tube making apparatus, the combination with the tube-forming die
and draw-bench mechanism, of a heating device comprising a refractory non-
conducting chamber having walls adapted to embrace the tube or portion of tube
to be heated, and containing a heat radiating charge or radiating surface
maintained at a high degree of incandescence.
46. In a tube making apparatus, the combination, with the tube to be heated,
of an electric heater and a support of insulating refractory material arranged
to hold the heating surface in effective heat-radiating proximity to the tube.
47. A tube heating apparatus consisting of a heat-radiator and a support for
the same made of insulating refractory material, said support being shaped so
as to approximately fit the tube and to permit of its passage along the same
without exposing the radiating surface to the surrounding atmosphere, sub-
stantially as described.
48. A tube heating apparatus consisting of a chamber made of refractory insulat-
ing material containing a conducting surface or material adapted to be heated to
incandescence by the passage therethrough of an electric current or currents,
means for passing the tube or portion of the tube to be heated along or over the
same within effective heat-radiating proximity to the incandescent surface or
material, and a removable cover for the radiator and tube to prevent loss of heat
by radiation into the surrounding atmosphere, substantially as described.
49. A tube heating apparatus consisting of one or more elongated heat-radiators
adapted to be traversed by the tube, and provided with electrodes or terminals
arranged to be connected with a suitable source of electric current, substantially
as described.
50. A tube heating apparatus comprising an elongated heat-radiating chamber
having a slot along its upper surface adapted to be closed by the tube in its
passage across the same, substantially as described.
51. In a tube making apparatus, the combination, with the tube-forming
mandrel and die, of an electric radiator projecting into the tube from said mandrel
with its heating surface in proximity to the meeting edges or seam of the tube,
and an external radiator co-operating therewith and having its heating surface
substantially in alignment with that of the inner radiator, substantially as
described.
52. The method of heating metal tubing preparatory to annealing, shaping,
brazing, welding or otherwise working or joining the same, which consists in
heating the tube or any desired portion thereof to the requisite temperature for
the work in hand, by means of heat radiated thereon from an electrically heated
body

page_text: 53. The method of heating metal tubing preparatory to annealing, shaping
brazing, welding, or otherwise working or joining the same, which consists in
heating the tube or the desired portion or portions thereof to a sufficient tempera-
ture for the work or operation to be performed, by means of heat radiated from
an electrically heated body while the tube, or the portion or portions thereof
subjected for the time to such radiation, is protected from free access of the
surrounding atmosphere.
54. The method of heating metal tubing preparatory to annealing, shaping,
brazing, welding or otherwise working or joining the same, which consists in
surrounding the tube or a portion thereof with a primary or inducing coil through
which the tube is free to move, thus constituting the tube or the portion thereof
surrounded by the inducing coil a closed secondary circuit of relatively lower
resistance, and in charging the primary coil with alternating currents and causing
the same to set up or induce in the tube, secondary currents having the requisite
heating effects, substantially as described.
55. An electric heating device consisting of a hollow inducing coil having a
magnetic envelop or sheathing, the said coil having a free inductive field within
the space enclosed thereby and being designed and adapted when energized to
induce heating currents in conducting bodies placed within or passing through
said field, substantially as described.
56. An electric heating device for heating tubular metallic objects, comprising
an inducing coil designed and adapted to surround said object or objects, and a
magnetic envelope or screen for the same whereby when said coil is energized
heating currents will be set up in the object or objects enclosed thereby, sub-
stantially as described.
In witness whereof, I, the said Elias Elkan Ries, have hereunto set my hand
and seal this 10th day of July 1899.
1
ELIAS ELKAN RIES.