Improvements in the Manufacture of Metal Tubes or Tubular Vessels.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Metal Tubes or Tubular
Vessels.
We, CLAUD THORNTON CAYLEY and REUBEN SAMUEL COURTMAN, both of
Acre Street, New Road, Wandsworth Road, in the County of Surrey, Engineers,
do hereby declare the nature of this invention and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:―
Our invention relates to the manufacture of metal tubes or cylinders, or of
tubular or cylindrical vessels or bottles for containing hydrogen, oxygen and other
gas under pressure, or for similar purposes. We manufacture such tubes, cylinders
or vessels from a solid block of metal, preferably steel, by or according to an
improved method or process comprising a series of operations as hereinafter
described.
We commence by employing moulds and punches or mandrels in such a manner
that after converting the solid block into a cup-shaped blank, the base or bottom
of which is of a diameter equal, or about equal to that of the finished article, we
proceed by elongating the same without materially altering its diameter somewhat
as described in the Specification of our former Letters Patent dated December 24th
A.D. 1886 and numbered 16943 and we continue the manufacture by drawing the
tube or tubular blank, while hot, through suitable dies and then by other operations
we convert the same into a finished tube or into a vessel for containing gas or for
other purposes.
We will now proceed to describe by the aid of the accompanying drawing, the
manner in which we carry our invention into practice.
Figure 1 shows a solid block such as we use for the production of a tubular
vessel or bottle for containing gas under pressure.
Figure 2 shows the said block after it has been pressed to the shape of the bottom
of the mould.
Figures 3 to 10 are longitudinal sections illustrating the result of the further
operations in the said manufacture that is to say.
Figure 3 shows the blank after it has been cupped or made hollow, by punching
it while in the mould.
Figures 4 and 5 show the same after it has been worked into a tubular form by
being passed while hot through suitable dies.
Figure 6 shows a tube or cylinder after it has been subjected to the process of
cold drawing.
Figure 7 shows one of our finished tubular vessels or bottles produced from a
solid block or blank.
Figure 8 shows such a vessel or bottle placed in an apparatus for closing the end
of the tube or cylinder.
Figures 9 and 10 show parts of the said apparatus.
The solid block Figure 1 must be of such dimensions as will give the required
weight to the finished article and after having been pressed, hammered or otherwise
worked into the shape shown in Figure 2 it is placed while hot in a suitable mould
and in this mould, or in a series of moulds, it is worked into the form of a hollow
blank or cup such as that shewn in Figure 3. Then this blank or cup is reheated,
and placed on a mandrel and subjected to a series of drawing operations through a
die or series of dies substantially as described in the Specification of our former
Letters Patent, January 6, A.D. 1888, and numbered 278, during which operations
it is reheated as often as thought necessary to keep the metal in a properly plastic
condition, for being successfully worked. By this hot drawing the tube is brought
to the condition shewn in Figure 5.

page_text: It will thus be seen that the solid block shown in Figure 1 has now been
converted into a hollow cylinder or tube of the same or about the same diameter
as that of the finished article but it has not yet been worked to the required finished
condition. If the finished article is to be a short tube we can now remove the
closed end, trim up the other end and complete the manufacture of the said tube by
subjecting it to a process of cold-drawing, by means of apparatus such as that used
for the hot drawing. By this cold drawing we bring the tube to the required length,
and thickness of its wall, and it will then be ready for use.
But although we can produce short tubes in this manner, we do not consider it
advantageous to make a finished tube of more than a few feet in length without the
further operations hereinafter described. That is to say for the production of a
finished tube according to our invention of more than about four feet in length, we
subject the tube after having punched or cut out or otherwise removed its closed
end, to the action of rolls. For this purpose we use rolls having a series of
grooves each successive groove being of smaller diameter than the preceding
groove.
We place the tube on a mandrel and pass the same between the said rolls. By
this operation the tube is brought, very nearly to the required finished length,
diameter and thickness of metal. It is then, if necessary or desirable, pickled to
remove the oxide or scale from its surface and is annealed and then finished by cold
drawing.
By the cold drawing of the tube we are enabled to reduce the metal thereof to
any required thickness, however slight that may be, while imparting to the tube
great strength and stiffness. We may complete such cold drawing in one operation,
or passage of the tube through the dies, or we may repeat such operation or passage
as often as may be necessary to produce the required result.
In the manufacture of a tubular vessel or bottle for containing gas under pressure
or for other like purpose we commence by subjecting a solid block of steel or iron
to the action of a punch or punches while in a mould and after hot drawing it to a
tubular form, we, if necessary pickle and anneal the tube previous to cold drawing
the same.
Then, by the operation of cold drawing, the vessel is brought to the
form shewn in Figure 6; that is to say-to a length somewhat exceeding that of the
finished vessel as will be apparent by the comparison of Figure 6 with Figure 7.
After the cold drawing is completed we cut off the surplus length from the upper
end of the tube and, if necessary, we turn or otherwise work the lower or closed
end, to the required shape and thickness. Then after heating the open end of the
vessel we place the said vessel in the mould a in Figure 8 for the purpose of closing
the open end and forming the neck of the vessel. The said mould has, at its lower
end, a block to support the said tube or cylinder against the action of the dies or
tools c, d, e which are operated by hydraulic pressure or by a hammer or otherwise
to force them down upon the end of the vessel. The die e is first used, then the
died and then the die e. Three of such dies used successively in the proper order
will generally be sufficient to complete the closing operation, but as many more as
be necessary or convenient can be employed.
may
We wish it distinctly understood that our invention is strictly limited to the pro-
duction of tubes or tubular or cylindrical vessels from a metal block such as can be
cut from a forged or drawn metal bar. In no case do we use a thin disc such as
could be taken from an ordinary rolled plate or sheet of metal, our object being
to insure a homogeneous condition of the metal throughout the entire substance
of the finished article which condition we believe to be practically unattainable
otherwise than by commencing with a solid block of metal such as we have above
described.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is
First. The improved method of manufacturing tubes or tubular or cylindrical

page_text: vessels from a solid block of steel or other suitable metal substantially as herein set
forth.
Second. A tube manufactured from a solid block of steel or iron by first punching
the said block while the same is in a mould as herein above described and then
finishing the tube by other operations.
Third. A tube which has been produced from a solid thick mass or block of
metal by a method or process wherein the said block is first worked into a cup-
shaped blank by punching while in a mould and then worked into a tubular form
by hot drawing through suitable dies and then after having its closed end removed
(and either with or without being subjected to the action of rolls) finished by cold
drawing all substantially as and for the purposes specified.
Fourth. A tubular or cylindrical vessel or bottle, for containing fluids under
pressure, which has been produced from a solid block of steel or other suitable
metal by first punching it in a mould and then hot-drawing it into a tubular form,
then cold drawing it and then closing its open end all substantially as and for the
purposes specified.
Dated this 23rd day of November 1891
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicants.