Improvements in the Manufacture of Composite Pipes and in Apparatus therefor.
Year: 1898

page_text: Date of Application, 6th Sept., 1893-Accepted, 19th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Composite Pipes and in
Apparatus therefor.
I, EDWARD IRVING BRADDOCK, of 70, Salem Street, Medford, Massachusetts,
United States of America, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to a composite non-corrodible pipe, which is stronger,
cheaper and more efficient than non-corrodible pipes now commonly produced
and known to me; and to an apparatus with which the composite pipe may be
anade.
In accordance with this invention, the composite pipe is made up of two or more
concentric tubes, one of which is composed of comparatively inexpensive and
strong, although easily corrodible metal having a relatively high melting point,
such as iron or steel, and which will be hereinafter referred to as the primary
tube, and the secondary or protecting tube or tubes are of metal having a relatively
low melting point, such as lead, tin, zinc or their alloys, commonly known in the
arts as non-corrodible metals.
The composite pipe may and preferably will be produced by chemically cleans-
ing the primary tube by pickling in the usual manner, treating the same with a
liquid flux, such as chloride of zinc, placing the primary tube upon a mandrel,
and immersing it in a tank of molten non-corrodible metal such as specified, after
which the primary tube is fed forward through a chilling die at the end of the
tank, wherein a composite pipe is formed with a tubular covering of the non-
corrodible metal, progressively built upon one or both surfaces of the primary
tube as fast as that tube advances into the chilling portion of the die.
Iron or steel tubes which have been previously chemically cleansed, fluxed and
tinned or galvanized, may be employed without further cleansing or fluxing and
a composite pipe may be produced therefrom by applying and uniting the non-
corrodible metal thereto as above described.
The union between the primary and secondary tubes is a molecular union
similar to that effected by such an operation as tinning, galvanizing, brazing or
soldering, but this invention is to be distinguished from the product of those pro-
cesses from the fact that by neither of them can a secondary tube of metal of any
substantial thickness be formed upon and united with either surface of a primary
tube.
Hereinafter, for the sake of brevity, the word “iron” only will be used when
naming the metal for the primary or corrodible tube, and the word "tin" when
naming the metal for the secondary or non-corrodible tube.
An apparatus by the aid of which composite non-corrodible pipes may be suc-
cessfully produced is illustrated in the drawings, wherein
Figure 1, is a longitudinal sectional elevation of the apparatus.
Fig. 2, is a horizontal section through the forming die, with the primary tube of
metal containing the mandrel inserted in said die."
Figura is a section on line z in Figure 2.

page_text: Figure 4, is a front view of the device within the tank, for engaging the rod
which holds the mandrel in a stationary position.
Figure 5, is a longitudinal section of the improved composite pipe, and
Figure 6, is a cross-section of such pipe.
Referring to Fig. 1 of the drawings, A, is a metal tank or vessel for holding
the metal from which the secondary or protecting tubes are to be formed, and in
which that metal is maintained in a molten condition by a furnace indicated by
a grate a¹. The tank is supported upon suitable walls a² a², the products of
combustion from the furnace having an outlet to the chimney at at. Preferably
the tank is constructed with an inclined bottom as shown, so that the primary
tubes to be covered, may be readily introduced into the forming die, which has a
similar inclination and is attached at one end of the tank, and thus the molten
metal may flow by gravity through such die and also through the interior of the
tube which is under operation when it is immersed in the bath of metal. The
broken line a may represent the level of the molten metal; b, is the iron tube to
be covered; 2, the mandrel around which the interior secondary tube c is formed
within the primary tube b. Upon the inner end of this mandrel longitudinal ribs
or wings are formed or attached, to serve as centering devices for the forming
portion 62 of the mandrel. The height of the projecting centering ribs upon the
mandrel and the sides of the mandrel itself, are determined by the
size of the bore of the primary tube and the size of the bore de-
sired for the composite pipe. 7* is an extension of the mandrel,
to which a rod 65 is hinged at 66. This rod is provided with a shoulder upon its
outer end to engage a standard 67, secured within the tank, to prevent the rod
and with it the mandrel, from being carried out of the tank with the tube b when
it is fed forward. d, is the cylindrical die in which the exterior secondary tube c
of the composite pipe is formed. d may be a portion of the same cylindrical tube
as the die d, but extending into the tank A, and it has formed upon its inner sur-
face, or connected therewith, ribs which serve to center the tube within the
died, and which form longitudinal grooves (Fig. 3) along the interior of that
portion, to permit the flow of molten metal into the die d.
Around the outer end of the die d is a chilling jacket B, provided with an inlet
pipe 10, and an outlet pipe 11. Within the tank A, and attached to the wall
thereof immediately back of the outlet into the forming die is a valve chamber 4,
through which the tube passes when inserted into the die, and when the tube b
with its mandrel is removed from the forming die, the outlet passage is closed by
means of a plunger valve d³, which is pushed down into the valve chamber d
across the passage leading to the forming die. d d are two grooved rolls which
guide the tube and move it forward through the tank and forming die. The
length of the ribs 63 upon the mandrel 2 should be sufficient to give a stable bear-
ing upon the interior of the tube b, and hold the mandrel proper, which is to deter-
mine the interior bore of the composite pipe, in an accurately central position
within the tube b, and also the length of the portion d should be sufficient to
give a stable bearing to the tube and hold it in an accurately central position
in the die d.
In Figs. 5 and 6, which represent the completed composite pipe, b, is the primary
tube of iron, c, the interior secondary tube of tin or similar metal, and the exterior
secondary tube. The thickness of these two secondary tubes may be regulated as
desired by varying the size of the mandrel 62 in relation to the bore of the tube
and the size of the interior diameter of the die d with relation to the exterior
diameter of the said tube b.
When it is desired to unite a secondary non-corrodible tube to the interior only
of the tube b, the grooves in the portion d', are omitted and thus leave a closely
fitting cylindrical collar around the exterior of the tube b, which will prevent
the flow of metal along the outside of it.
The operation of forming a composite pipe in this apparatus according to the
method above described is as follows:-
Having filled the tank A with molten tin or similar non-corrodible metal up to

page_text: _a level, for instance, as indicated by the broken line a, a section of iron tube bis
slipped over the mandrel and its retaining rod b; the end of the tube in which
the mandrel is located is inserted into the bath of molten metal, pushed between
the rolls do, thence against the valve, that valve is then raised and the tube b
with the mandrel is moved forward through the centering portion d¹, out into
the die."As soon as the valve d' is raised, the molten metal will flow out into the
die d, but before it can flow out from the end of that die, the chilling jacket B
will have congealed and solidified it, thus forming a solid plug of metal which
will prevent the escape of any portion of the metal in the molten state, then as the
tube b is caused to pass along over the mandrel and through the forming die, this
plug of nietal will be pushed out, the molten metal in the tank will flow forward
through the grooves in the portion and between the ribs 63 on the inner end
of the mandrel. Immediately after passing beyond thèse grooves into the inner
part of the die d, and around the mandrel 2, the molten metal will begin to be
cooled by the chilling jacket around the outer end of the forming die, and before
it has passed far within the portion of that die which is surrounded by the chilling
jacket, this "non-corrodible metal will be congealed and solidified around the
exterior and upon the interior of the tube and securely united therewith.
As the movement of the tube b is continued through the die d the molten metal
will continue to flow through the said grooves into the forming die and around
the mandrel, and will be solidified around and within the tube b at the part near
the end of said die and mandrel, this solidified portion being always followed by
and immediately joined to other portions of such metal in a molten condition,
which in turn is chilled as the iron tube is moved forward through the die. The
chilling of the metal in this manner to form the secondary tubes is what I prefer
to designate as a progressive chilling of the non-corrodible metal' and the coni-
pleted composite pipe thus formed is readily pushed out of the die and off from
the mandrel. As soon as one length of pipe has been fed through the die so that
its rear end has past the hinge 66, the rod b is raised from the tank to the position
indicated by dotted lines, Fig. 1; another length of pipe slipped over the rod,
entered between the feeding rolls do, and the rod with the tube thereon dropped
back to the position shown in full lines in Fig. 1, and the pipe forming process
continued; and in this way the manufacture is substantially continuous as long as
desired, a fresh supply of tin or other similar metal being supplied to the tank as
it is consumed in the formation of the non-corrodible covering for the iron tube.
From the above description, it will be seen that a composite non-corrodible pipe
may be formed of a corrodible iron or steel tube b and a non-corrodible tube c
within the tube b and joined thereto by a molecular union of the metals of said
tubes, so that when the composite pipe is subjected to the uses to which non-
corrodible pipes, made wholly of lead, zinc, tin or their alloys, are put, the tube c
does not expand and contract independent of the iron tube b, and consequently
does not crack and break or become brittle, but remains for an indefinite time in
its original condition, firmly and molecularly united to the iron tube and com-
pletely protecting the same against corrosion. The same is also true of the tube c³
on the outside of the tube b. The composite non-corrodible pipe hereindescribed,
is stronger, cheaper and more efficient than pipes of the same size made wholly
of non-corrodible metal.
It is to be particularly noted that the product above described, is to be distin-
guished from an iron or steel tube coated with a film of non-corrodible metal by
dipping or galvanizing an iron or steel tube, in that the inner non-corrodible
tube of the said product is distinctively a tube of substantial thickness, such as
could be recognized and used as a tube or pipe were the iron or steel tube absent.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to he performed, I declare that what I
claim is:
1. A composite pipe, consisting of two axially concentric tubes of metal mole-

page_text: 'cularly united together, the outer one of iron or steel, and the inner one of non-
corrodible metal of relatively lower melting point, such as tin, zinc, lead or their
alloys.
2. A composite pipe, consisting of an iron or steel tube inclosed between and
'molecularly united to two axially concentric tubes of non-corrodible metal of rela-
tively lower melting point, such as tin, zinc, lead or their alloys.
3. A composite pipe, consisting of an iron or steel tube, a tube of non-corrodible
metal such as specified within said iron or steel tube and molecularly united
thereto, and a second tube of non-corrodible metal as specified on the outside of
the iron or steel tube, and molecularly united thereto and of less thickness than
the non-corrodible tube within said iron or steel tube.
4. An apparatus for the manufacture of composite non-corrodible pipe, from
a tube of iron or steel and a non-corrodible metal of lower melting point, com-
prising a tank to contain the non-corrodible metal and means to keep it in a
molten condition, an outlet pipe which extends into and outside of said tank, and
has devices within the inwardly extending portion to center the iron tube, and a
chilling jacket around the outwardly extending portion of the outlet pipe, a man-
drel extending through said outlet pipe to determine the bore of the composite
pipe, and devices upon said mandrel to center it within the said iron tube, sub-
stantially as described.
5. An apparatus for making composite pipe of a primary tube of iron or steel
and an axially concentric tube of metal having a substantially lower melting point
than that of the primary tube; comprising a vessel to hold and maintain in a
molten state the metal of the lower melting point, means for heating said vessel,
an opening in one end of said vessel to receive the primary tube; a mandrel
with devices to center it in the primary tube, yet to permit the
passage of molten metal; a chilling chamber outside of the said vessel adjacent
to the said opening therein; mechanism to maintain the said mandrel within the
primary tube at the location of the chilling chamber, and means to feed the
primary tube through the openings in said vessel and chilling chamber and over
the said mandrel, substantially as described.
6. An apparatus for the manufacture of composite pipe of corrodible and non-
corrodible metal, comprising a tank or vessel having an inclined bottom and
provided with an outlet pipe for the flow of molten metal therefrom, means to
heat said vessel, a mandrel to determine the bore of the composite pipe inserted
into said outlet pipe and extended into said tank and upon which the corrodible
pipe is placed, and a forming and chilling die into which said mandrel is extended
to form a space between it and the corrodible pipe within the said die, into which
the molten metal flows and wherein it is solidified, substantially as described.
7. An apparatus for the manufacture of composite pipe of corrodible and non-
corrodible metals, comprising a tank or vessel to contain a bath of molten non-
corrodible metal, provided with an opening for the insertion of a corrodible pipe
into said vessel, means to heat said vessel, an outlet pipe in said vessel, which pipe
is adapted to receive the corrodible tube and is provided upon its interior with
one or more longitudinal channels or grooves for the passage of non-corrodible
metal, a die to form the exterior of the composite pipe having a chilling jacket
and located axially in line with said outlet pipe, and a mandrel extended from
within said tank through the outlet pipe and into the said chilling die and upon
which the corrodible pipe is placed, substantially as described.
8. An apparatus for the manufacture of composite pipe of corrodible and non-
corrodible metals, comprising a tank or vessel to contain a bath of molten non-
corrodible metal, means to heat said tank, an outlet from said tank of the size of
the external diameter of the corrodible tube and having one or more grooves or
channels extended longitudinally through sail outlet, a die for forming the non-
corrodible tube, which is of larger diameter than the said outlet, and is located
outside of said tank, a chilling jacket upon the said die, and a mandrel of less

page_text: diameter than said outlet and extended through the outlet and into said die, sub-
stantially as described.
9. An apparatus for the manufacture of composite pipe of corrodible and non-
corrodible metals, comprising a tank or vessel to contain the non-corrodible metal
and maintain it in molten condition, provided with an opening for the insertion
of a corrodible pipe into said vessel and with an outlet for said metal and corrodible
pipe, means to heat said vessel, a chilling die located axially in line with and
beyond said outlet, and a mandrel within the tank extended through the outlet
and into said chilling die and of a diameter within the die equal to the bore desired
of the non-corrodible tube to permit the composite pipe to be moved from within
the tank over the mandrel and through the chilling die, substantially as described.
10. An apparatus for the manufacture of composite pipe of corrodible and non-
corrodible metals, comprising a tank or vessel to contain a bath of molten non-
corrodible metal, provided with an opening for the insertion of a corrodible pipe
into said vessel and with an outlet for the passage of a corrodible tube and said
molten metal, means to heat said vessel, a chilling die located axially in line with
said outlet, a mandrel extended from within the tank through said outlet and
corrodible tube into said chilling die and of a diameter within the die equal to the
bore desired of the non-corrodible tube, devices to render the mandrel stationary,
and means thereon to center it within the tube of corrodible metal, substantially
as described.
11. An apparatus for the manufacture of composite pipe of corrodible and non-
corrodible metals, comprising a tank or vessel to contain a bath of molten non-
corrodible metal, provided with an inlet opening for the insertion into the tank
or vessel of the corrodible tube and with an outlet opening for the passage of the
corrodible tube and said molten metal out of said tank; means to heat said tank
or vessel; a chilling die located axially in line with said outlet opening; a
mandrel extended from within the tank through said outlet opening and corrodible
tube into said chilling die and of a diameter within the die equal to the bore
desired of the non-corrodible tube; and means on said mandrel to center it within
the tube of corrodible metal, substantially as described.
Din this 6th day of September 1898.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.