Improvements in the Manufacture of Pipes.
Year: 1895

page_text: Date of Application, 16th Apr., 1895
Complete Specification Left, 16th Jan., 1896-Accepted, 22nd Feb.. 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Pipes.
-I, CARL GUSTAF PATRIK DE LAVAL of 16 Handtverkaregatan, Stockholm
Sweden, Doctor of Philosophy and Engineer do hereby declare the nature of this
invention to be as follows:-
Pipes and other hollow bodies have heretofore been manufactured in such a
manner that a hollow bar is rolled from a hollow cast or punched body of metal,
which bar is changed afterwards by any approved process into a circular pipe.
One method of producing this change into a circular pipe was that one end of the
hollow bar is closed while steam or gas of high pressure is introduced into the other
end, so that in this manner the pipe is enlarged into circular shape. Whatever be
the method of transforming the shape of the hollow bar, it is subject to the
objection that the finished tube shews, at the points which before were the corners
of the hollow bar, not the same thickness as at the remaining points that depressions
remain at those points and the material is not subjected at those points to the same
treatment to which the remaining parts of the tube are subjected. These points,
therefore offer less resistance to strain, and impart thereby a certain degree of
weakness to the tubes.
The object of this invention is to obviate the defects referred to and to obtain in
the manufacture of seamless tubes from a hollow body by means of rolling it into
a flat bar and then converting this bar into a circular tube, a uniform thickness
throughout the cross section of the tube, whereby the material receives throughout
a uniform treatment and consequently a uniform durability or strength.
In this invention therefore the flat bar during an intermediate stage of the process,
before it is charged into a tube is subjected to a rolling operation for opening the
bar, in one direction, and then to a second rolling operation at right angles to
the former.
By the successive rollings, the bar is worked upon at those points which heretofore
formed a ridge, so that the thickness of the material is reduced, even at those
points, to the required degree. This successive rolling of the bar in directions at
right angles to each other can be repeated several times so as to produce the final
uniform thickness of the tube.
The changing of the bar into a circular seamless tube can be produced in a very
convenient manner in that the bar, instead of being expanded into a tube, as before
described, is placed on its edge, is then carefully rolled down until the bar has been
opened sufficiently, and then the same is finished by being rolled over a suitable
core or mandrel.
In carrying out my improved process of making seamless tubes, a hollow body
of suitable metal is subjected first to a rolling action say between rolls having
shallow circumferential grooves, so that a flattened bar is obtained, in which the
material is mainly acted upon by the rolls at two opposite points. The rolling
action on the flat bar is preferably continued until the same receives a thickness
which corresponds to double the thickness of the wall of the finished tube. When
the body is thus rolled out into the flattened bar the edges of the bar have a greater
thickness of material, so that unevennesses would appear in the tube if the bar
were rolled out directly into a finished tube. For obviating this defect, the
Blattened bar is passed through a second pair of rolls having nearly semi-circular
grooves, which gradually change the shape of the flattened bar to a circular shape,

page_text: in which the upper and lower points are of less thickness, while the edges are
thicker and show slight interior longitudinal depressions. Before the flattened bar,
however, assumes the tubular shape it passes through the oval form that is to say,
the flattened bar is gradually opened until it assumes the tubular shape. By rolling
the bar between a pair of rolls having semi-circular grooves, the bar is finally
changed into a tube which has an exterior cylindrical shape. For the purpose of
removing the aforesaid thicker parts and the interior longitudinal depressions in
said thicker parts it is necessary to subject the tube to another rolling, by subjecting
the same to the action of a pair of rolls having flat grooves with deeper depressions
near the ends of the grooves. While the tube is subjected to the rolling action of
this pair of rolls it passes through an intermediate shape until it finally assumes
the shape of a flattened hollow bar having rounded off edges. By the rolling of
the tube into this hollow flattened shape, the aforesaid thicker portion and interior
depressions disappear entirely, so that the tube is changed into a flattened bar of
uniform thickness throughout with rounded off edges at the aforesaid points.
This flattened bar is rolled out until the required thickness of the finished tube is
obtained. The flattened bar is then transferred to another set of rolls having
semi-circular grooves corresponding to the exterior radius of the tube to be
manufactured, and is subjected to a careful rolling action by the same, so that the
flattened bar gradually opens again and forms a tube of uniform thickness and
exterior and interior cylindrical shape. If however, a smaller thickness and a
greater diameter in the finished tube is to be produced, then the flattened bar is
again rolled out into a flat bar and then opened again by rolling it alternately in
directions at right angles to each other until the required diameter and thickness
of the tube is obtained.
Dated this 16th day of Anvil 1805
JENSEN & SON,
77 Chancery Lane, London, W.C., Patent Agents.
не мапигастите от гіров.
I, CARL GUSTAF PATRIK DE LAVAL, of 16A Handtverkaregatan, Stockholm,
Sweden, Doctor of Philosophy and Engineer, 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 :-
Pipes and other hollow bodies have heretofore been manufactured in such a
manner that a hollow bar is rolled from a hollow cast or punched body of metal,
which bar is changed afterwards by any approved process into a circular pipe.
One method of producing this change into a circular pipe was that one end of the
hollow bar is closed while steam or gas of high pressure is introduced into the other
end, so that in this manner the pipe is enlarged into circular shape. Whatever be
the method of transforming the shape of the hollow bar, it is subject to the
objection that the finished tube shews, at the points which before were the corners
of the hollow bar, not the same thickness as at the remaining points, that depressions
remain at those points and the material is not subjected at those points to the same
treatment to which the remaining parts of the tube are subjected. These points
therefore offer less resistance to strain, and impart thereby a certain degree of
weakness to the tubes.
The object of this invention is to obviate the defects referred to and to obtain in
the manufacture of seamless tubes from a hollow body by means of rolling it into a
flat bar and then converting this bar into a circular tube, a uniform thickness
throughout the cross section of the tube whereby the material receives throughout
a uniform treatment and consequently a uniform durability or strength.

page_text: In this invention therefore the flat bar during an intermediate stage of the
process, before it is changed into a tube, is subjected to a rolling operation for
opening the bar, in one direction, and then to a second rolling operation at right
angles to the former.
By the successive rollings, the bar is worked upon at those points which heretofore
formed a ridge, so that the thickness of the material is reduced, even at those
points, to the required degree. This successive rolling of the bar in directions at
right angles to each other can be repeated several times so as to produce the final
uniform thickness of the tube.
The changing of the bar into a circular seamless tube can be produced in a very
convenient manner in that the bar, instead of being expanded into a tube, as before
described, is placed on its edge, is then carefully rolled down until the bar has been
opened sufficiently, and then the same is finished by being rolled over a suitable core
or mandrel.
:
For clearly illustrating my invention, the accompanying drawings represent
different stages of my improved process.
Fig. 1 representing the first rolling of the hollow body into a flat bar,
Fig. 2 the second rolling of the flat bar so as to open the same again,
Fig. 1 represents a cross-section of the bar while the same is in process of being
rolled from the flat shape shown in Fig. 1 to the circular shape shown in Fig. 2,
Fig. 3 represents the closing down of the opened tubular body into a flattened
bar,
Fig. 2 represents an intermediate stage of this step of the rolling process,
Fig. 4 represents the final opening and completing of the seamless tube by
subjecting the flattened bar shown in Fig. 3 to an opening and final conversion into
a tube of uniform thickness.
Similar letters of reference indicate corresponding parts.
In carrying out my improved process of making seamless tubes, a hollow body of
suitable metal is subjected first to a rolling action between rolls R, R', having
shallow circumferential grooves, so that a flattened hollow bar is obtained, in which
the material is mainly acted upon by the rolls at the points A and B. The rolling
action on the. flat bar is preferably continued until the same receives a thickness
which corresponds to double the thickness of the wall of the finished tube. When
the body is rolled out into the flattened bar shown in Fig. 1, the edges of the bar
at the points C and D have a greater thickness of material, so that unevennesses
would appear in the tube if the bar were rolled out directly into a finished tube.
For obviating this defect, the flattened hollow bar is passed through a second pair
of rolls R², R³, Fig. 2, having nearly semi-circular grooves, which gradually change
the shape of the flattened hollow bar to a circular shape, in which the points B
and A are of less thickness, while the edges C and D are thicker and show slight
interior longitudinal depressions. Before the flattened bar, however assumes the
shape shown in Fig. 2, it passes through the oval form shown in Fig. 14, that is to
say, the flattened hollow bar is gradually opened until it assumes the tubular shape
shown in Fig. 2. By rolling the bar between a pair of rolls having semi-circular
grooves, the bar is finally changed into a tube which has an exterior cylindrical
shape, as shown in Fig. 2. For the purpose of removing the thicker parts C and D
and the interior longitudinal depressions in said thicker parts C and D, it is
necessary to subject the tube to another rolling, by subjecting the same to the
action of a pair of rolls R, R, Fig. 3, having flat grooves with deeper depressions
near the edges of the grooves, as shown. While the tube of the cross-section shown
in Fig. 2 is subjected to the rolling action of the pair of rolls shown in Fig. 3 it
passes through the intermediate stage of the shape shown in Fig. 2ª until it finally
assumes the shape of a flattened hollow bar having rounded off edges, as shown in
Fig. 3. By rolling the tube into this hollow flattened shape, the thicker portions
and interior depressions at C and D disappear entirely, so that the tube is changed
into a flattened hollow bar of uniform thickness throughout with rounded off edges
at the points A and B, as shown in Figure 3. This bar is rolled out until the
7

page_text: required thickness of the finished tube is obtained. The bar is thence transferred
to another set of rolls R' R', Fig. 4, having semi-circular grooves corresponding to
the exterior radius of the tube to be manufactured, and is subjected to a careful
rolling action by the same, so that the flattened bar shown in Fig. 3 gradually
opens again and forms a tube of uniform thickness and exterior and interior
cylindrical shape, as shown in Fig. 4. If, however, a smaller thickness and a
greater diameter in the finished tube is to be produced, then the flattened bar shown
in Fig. 3 is again rolled out into a flat bar and then opened again by rolling it
alternately in directions at right angles to each other until the required diameter
and thickness of the tube is obtained.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In manufacturing seamless tubes from a hollow body by means of rolling it
into a flat hollow bar, the process herein described, which consists in rolling the
flat hollow bar, at an intermediate stage of the manufacture edgewise between
flattened rolls, so as to flatten the hollow bar in this direction thus rendering the
thickness of the wall uniformn throughout the cross-section of the hollow bar,
substantially as set forth.
2. The manufacture of seamless tubes from a hollow body by rolling the same
into a flat hollow bar, then opening it by passing it edgewise between rolls with
about semi-circular grooves, then flattening it between rolls with flat shallow grooves
for rendering the thickness uniform at top and bottom and throughout and then
finishing it in the ordinary manner substantially as set forth..
Dated this 16th day of January 1806
JENSEN & SON,
77 Chancery Lane, London, W.C., Patent Agents.