Improvements in the Manufacture of Metallic Tubes for Use in Steam: Boilers, and for other purposes.
Year: 1894

page_text: Date of Application, 19th May, 1894
Complete Specification Left, 13th Mar., 1895-Accepted, 13th Apr., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Metallic Tubes for Use in Steam:
Boilers, and for other purposes.
We, THE CREDENDA TUBE COMPANY LIMITED, of Smethwick, in the
County of Stafford, Tube Manufacturers and WILLIAM MICKLEWRIGHT, of
No. 97 Crockett Road, Handsworth, in the County of Stafford, Mechanical
Engineer and Manager of Tube Works do hereby declare the nature of this:
invention to be as follows:
:-
The said invention relates to the manufacture of tubes used for steam boilers and
other purposes such for example as condensers and generally for all purposes where
a shoulder of larger diameter than the body of the tube is required at one or both
ends of the tube or where an enlarged shoulder is required at one end and an
internal shoulder or thickened part is required at the other end.
The said invention is applicable to the manufacture of tubes of steel, iron,
copper, brass and generally of such metals and metallic alloys as tubes are or may
be made of.
We will describe the said invention in connection with the manufacture of a
steel tube for a steam boiler.
We take a steel tube having the external and internal diameter which the
shoulder of the finished tube is intended to have. We introduce into the said tube
the bulb of a bulb mandril to the distance at which it is intended that the
internal thickening shall set in. We draw the tube through a draw plate the draw
hole in which has the diameter which it is intended the body of the finished tube
shall have.
In the drawing process that end of the tube near which the bulb of the mandril
is situated is reduced both in external and internal diameter the contraction of the
tube externally causing the thickening of the metal thereby reducing the internal
diameter of the tube at that part and forming an internal shoulder. As the drawing
proceeds the reduction of the external diameter of the tube proceeds, but the bulb
of the mandril being situated in the eye of the draw plate the contraction of the.
internal diameter is prevented by the mandril and the metal is reduced in thickness.
The drawing process is continued until that part of the tube to be left of the
original size reaches the draw plate when the drawing process is stopped. There
is thus produced a tube having at the end not operated upon a shoulder of the
size of the original tube having a body of less diameter and of less thickness of
metal than the original tube and having at the end first operated upon an internal
thickening or shoulder. In order to produce at the last described end of the tube
a shoulder similar to that at the other end of the tube the mandril is withdrawn
and reintroduced stalk end first. By now drawing the bulb of the mandril through
the thickened end of the tube that end is expanded and a shoulder formed similar
to the shoulder left on the other end of the tube.
The tube may be operated upon either hot or cold and the drawings described
may either be effected at one or more operations.
Dated this 19th day of May 1894.
W. T. WHITEMAN,
Agent for the Applicants..

page_text: Improvements in the Manufacture of Metallic Tubes for Use in Steam
Boilers, and for other purposes.
We, THE CREDENDA TUBE COMPANY LIMITED, of Smethwick, in the
County of Stafford, Tube Manufacturers, and WILLIAM MICKLEWRIGHT, of
No. 97 Crocketts Road, Handsworth, in the County of Stafford, Mechanical
Engineer and Manager of Tube Works, 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 :-
This invention relates to the manufacture of drawn metal tubes having an
external shoulder or thickened part at one or both ends thereof, with or without
similar intermediate shoulders or thickened parts; or having an internal thickened
part at one end and an external thickened part at the other end.
The said tubes which may be made of steel, iron, copper, brass or other metal
or alloy are intended for use in steam boilers, condensers and similar apparatus and
for many other purposes.
Referring to the accompanying drawings
Figures 1 to 4 are longitudinal central sections of tubes having shoulders or
thickened parts made according to this invention; Figures 5, 6 and 7 illustrate the
manner in which these tubes are manufactured from plain tubes, that is to say,
tubes having uniform external and internal diameters throughout their length.
Figure 5 is a central longitudinal section of a plain tube.
Figure 6 illustrates the operation of drawing such a tube into that shown in
Figure 1.
Figure 7 illustrates the operation of drawing a plain tube into the tubes shown in
Figures 2 and 4.
A is the body of the tube; B, B are the thickened portions thereof, whether
external or internal; C is the die or draw plate; D is a mandrel having an
enlarged head or bulb D' at the end.
To draw the tube indicated by Figure 1 we take a plain tube having the same
internal diameter as the finished tube and a thickness equal to that of the thick
end of the said finished tube, and we set down or reduce one end of the tube and
form a screw thread on the same as indicated in Figure 5 to fit the coupling of the
drawing apparatus. We then introduce into the tube the bulb mandrel D the
head D¹ of which just fits the said tube, and we proceed to pass the tube through
a draw-plate C having an eye suitable for reducing the external diameter of the
plain tube to that required for the body of the finished tube. The draw plate may
be stationary and the tube passed through it, or the tube may be stationary and the
draw plate passed over it as is well understood in tube drawing. When the tube
is moved it is drawn between the bulb D¹ and the draw plate in the direction
shown by the arrow in Figure 6. Its thickness is reduced by this process and
the length is of course correspondingly increased as will be well understood.
When the point is reached at which the shoulder or thickened part is required
to commence, the operation is stopped, the tube is withdrawn from the draw plate,
and the reduced end or nozzle is then cut off, we thus produce a tube similar to
that shown in Figure 1.
The tube may be drawn either hot or cold and either in one operation or in
several operations according to the difference of thickness between the thin and
the thick portions of the finished tube.
+
To produce the tube shown in Figure 4, the bulb of the mandrel is passed into
the tube as far as the point at which the thinning of the metal is required to
commence as shewn in dotted lines Figure 7 and then the tube is passed through

page_text: the draw-plate in the direction indicated by the arrow. During the first part of
this operation the tube not being supported internally is contracted in diameter
without reduction in thickness, an internal shoulder being thereby produced. But
as soon as the bulb has been brought into the eye of the draw plate as shewn in
full lines Figure 7 it prevents further contraction of the tube during the drawing
which is then continued and completed while the bulb is retained within the draw-
plate in the manner described with reference to Figure 1.
To produce the form of tube shown in Figure 2 a tube similar to that shown in
Figure 4 is taken and the bulb mandrel is introduced in the reverse direction and
drawn through it, the metal at the reduced end being thereby expanded and the
internal shoulder converted into an external shoulder.
To produce the form of tube shown in Figure 3 we begin in the manner
described for producing that shewn in Figure 4, and when the mandrel has reached
the point where the second shoulder commences we temporarily withdraw it and
proceed with the drawing through the draw plate alone, thus producing a second
contraction of the tube; we then reintroduce the mandrel and continue the drawing
with draw plate and mandrel until the third shoulder is reached, when the drawing
operation is stopped and the draw plate pulled back. The nozzle is then cut off
and the bulb mandrel reversed and drawn through the tube whereby the internal
shoulders are expanded and converted into external shoulders as described with
reference to Figure 2. It is obvious that we may produce in a similar manner an
external or internal shoulder or shoulders between the ends of a tube such as that
shown in Figure 4.
By transversely dividing a tube such as that shown in Figure 3 we can produce
two tubes thickened externally at both ends.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that we
do not claim a tube having a uniform external diameter and internal shoulders
or thickened portions, manufactured from a tube of larger external diameter
as set forth in the Specification of Charles Leslie Stiff No. 21822 but what we
claim is:-
1. A tube having an external shoulder or thickened part at one end or at
both ends (with or without a shoulder or shoulders between the ends produced
by drawing a plain tube through a draw plate or die with a mandrel inside the tube,
substantially as set forth.
2. A tube baving an external shoulder or thickened part at one end and an
internal shoulder or thickened part at the other end as shewn in Figure 4 (with or
without an external or internal shoulder or shoulders between the ends) produced
by drawing a plain tube through a draw plate or die with a mandrel inside the tube,
substantially as set forth.
Dated this 13th day of March 1895.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.