Improvements in the Manufacture of Tubes for Bollers, Condensers, and similar Apparatus.
Year: 1891

page_text: Date of Application, 14th Mar., 1891
Complete Specification Left, 14th Dec., 1891-Accepted, 14th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Tubes for Bollers, Condensers,
and similar Apparatus.
1. Los Sivagas, of Belle Vun, Boxley, in the County of Kent, Engineer,
do hereby declare the nature of this invention to be as follows:-
My invention relates to the manufacture of tubes for boilers, condensers and
other apparatus in which it is desirable to employ tubes having a large area of
heating or cooling surface.
My improved tubes are made with longitudinal ridges and depressions, or corru-
gations, preferably extending nearly throughout their length, the ends of the tube
being made circular to facilitate the securing of the same in the tube-plates or
other parts in which they are to be secured.
In the manufacture of my improved tubes, I find it advantageous to proceed as
follows, riz. I first make a tube of the required diameter, and I then, by rolling
or otherwise, form in the said tube longitudinal depressions, commencing a short
distance from one end of the tube and terminating a short distance from the other
end thereof.
In this manner I greatly increase the area of both the internal and the external
surface of the tube. Moreover, in the case of boiler-tubes, the internal surface
of the depressed portions of the tube will be very effectually subjected to the
action of the flames and heated products of combustion passing through the said
tube.
A convenient form of apparatus for forming the corrugations in my improved
tubes, comprises a carrier adapted to slide to and fro upon the tube and provided
with rolls which are adjustable towards and away from the centre or axis of the
tube. There must be as many of these rolls as it is desired to form depressions in
the tube. I provide suitable means whereby the said carrier may be conveniently
moved to and fro upon the tube. I also provide a mandrel the shape of which
in transverse section corresponds to that of the interior of the corrugated part of
the finished tube. This mandrel is placed within the tube so that it is between
the said rolls, and the said mandrel is arranged to be moved to and fro with the
aforesaid carrier.
Or the said mandrel may be made of the same length as the corrugations to be
formed in the tube, and may be held stationary within the tube while the carrier
is moved to and fro upon the outside thereof. Or, in place of the rolls arranged
in the aforesaid carrier, I employ rolls supported in a stationary frame and capable
of adjustment therein, and I provide means whereby the tube may be moved to and
fro between the said rolls, a suitable mandrel being held within the tube during
the rolling operation.
I do not, however, limit myself to the use of any particular form of apparatus
in the manufacture of my improved tubes, as such tubes can be manufactured
in any convenient manner.
In some instances, I make the tube with alternate corrugated and plain or
uncorrugated portions, that is to say, in the case of a circular tube, with circular
portions at suitable intervals throughout its length and with depressions or corru-
gations between such circular portions. The resistance of the tube to external
pressure can thus be increased.
D
1001
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Tubes for Boilers, Condensers,
and similar Apparatus.
I, LOUIS SILVERMAN, of Belle Vue, Bexley, in the County of Kent, 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 :-
My invention relates to the manufacture of tubes for boilers, condensers and
other apparatus in which it is desirable to employ tubes having a large area of
heating or cooling surface in proportion to their diameter.
My improved tubes are made with longitudinal corrugations, the said corruga-
tions preferably extending nearly throughout the length of the said tubes, the ends
of the tube being preferably left plain to facilitate the securing of the same in
the tube-plates or other parts in which they are to be secured.
In the manufacture of my improved tubes, I find it advantageous to proceed as
follows, riz. I first make or obtain a tube of the required length and diameter,
and then form in the said tube longitudinal depressions, commencing a short
distance from one end of the tube and terminating a short distance from the other
end thereof. The said tube may be thus worked either while hot or while cold.
In this manner I greatly increase the area of both the internal and the external
surfaces of the tube in proportion to its diameter. Moreover, in the case of
boiler-tubes, the internal surface of the inwardly depressed portions of the tube
will be very effectually subjected to the action of the flames and heated products
of combustion passing through the said tube, with the result that a greatly
improved circulation is obtained in any boiler to which the said tubes are fitted.
Another advantage of the tubes formed as herein described is that both the
outside and inside thereof may be readily cleaned by the usual or any suitable
means.
In order that my invention may be clearly understood I will now proceed to
describe the same with reference to the accompanying drawings, in which
Figure 1 represents in side elevation a plain tube previous to being corrugated
with longitudinal corrugations according to my invention.
Figure 2 is a side elevation of the said tube after it has been corrugated with
parallel longitudinal corrugations which extend uninterruptedly for nearly the
whole of its length.
Figure 3 is a transverse section of Figure 2 through the corrugated portion of
the tube.
Figure 4 shows in side elevation one form of mandrel which is employed, as
hereinafter described, in the formation of such a tube as is illustrated in Figure 2
for example.
Figure 5 is a cross section of the said mandrel.
Figure 6 is side elevation of a tube formed according to my invention with
discontinuous or interrupted longitudinal corrugations.
Figure 7 is a cross section of a tube in which the corrugations are deeper thon
in the figures previously referred to.
Figure 8 is a cross section of a tube such as would be employed for instance in
a marine boiler the corrugations being more numerous than in the tubes shown in
preceding views, which illustrate tubes of a smaller size such as may be used for
example in a locomotive boiler.
Figure 9 is a side elevation of a portion of a machine by means of which plain
tubes may be corrugated with the said longitudinal corrugations.
Figure 10 is an end elevation of Figure 9.
Like letters indicate the same part throughout the drawings.
With reference to Figures 1 to 8, AA are the said longitudinal corrugations.

page_text: The said corrugations as hereinbefore stated may be continuous as in Figure 2 or
may be interrupted by plain surfaces B as in Figure 6. C C are the plain
surfaces left at the tube ends so that they may be conveniently fitted into tube-
plates.
With reference to Figures 9 and 10 D is a table or bed, E is a head-stock which
may be secured upon the bed D at any convenient point. The said headstock has
a central orifice through which the tube to be corrugated may pass. F F are
rollers which are free to rotate on pins Fearried in the ends of spindles G. The
said pins are preferably made hollow as at F and a cooling liquid is circulated
by any suitable means through the hollow interiors thereof to keep the pins cool
when the apparatus is employed upon hot material. The said spindles are grooved
at G and are movable endwise in guides E' in the headstock E. Set screws G³
are provided in the walls of the guides and enter the said grooves (i) to exert
sufficient pressure therein to retain the spindles G in any position to which they
may be moved. The said set screws and grooves net also to prevent the spindles
from rotating upon their axes.
are screws which are inserted into the screwed portions E2 of the guides E¹
and bear upon the ends of the spindles G.
I are bevel pinions in which are formed square axial holes so that the said
pinions may be placed upon the squared extensions of the screws H. The said
bevel pinions are prevented from moving end wise upon the squared extensions by
wings E formed upon the headstock E and bearing upon the outer end faces of the
said pinions, the inner end faces of which bear upon the headstock E. The
said squared holes and the squared extensions of the screws are provided in
order that the said screws may be able to move end wise relatively to the pinions I,
and may rotate with but not relatively to the said pinions.
The said pinions I gear with a bevel wheel J. The said bevel wheel Jis
provided with a boss Jof large diameter and is carried upon the bearing K, the
said bearing being provided with a large axial opening, in line with the herein-
before mentioned central orifice of the head-stock. J' is a handle which may be
inserted in one or other of the sockets upon the bevel wheel J to rotate the said
wheel.
The said apparatus operates as follows:-The tube which is to be corrugated
has a mandrel such for example as is shown in Figure 4 inserted within it, the said
mandrel being somewhat smaller than the diameter of the tube in its plain or
uncorrugated condition but the same in cross section as that of the interior of
the corrugated part or parts of the finished corrugated tube. The end of the tube
is passed through the orifices of the bevel wheel bearing and the headstock, and
is gripped by a chuck or by other suitable means such as are commonly employed
in the operation of drawing seamless tubes.
The bevel wheel is then rotated by means of the handle J and rotates the
pinions I, and they in turn rotate the screws H by means of the hereinbefore
mentioned squared extensions so that the said screws move the spindles G inward
and the rollers F are forced against the outer surface of the tube and force it into
the grooves of the mandrel as shown in Figure 10. The tube is then drawn by
any suitable incans through the reduced space between the rollers F which rollers
act as a die and form corrugations in the tube as it is drawn between them. By
rotating the bevel wheel the screws H may be moved outward away from the
tube at any moment to allow the rollers to rise out of the depressions in the
tube and leave any portion of it plain as at B or C Figures 2 and 6.
I provide suitable means whereby the movement of the tube is automatically
stopped when the corrugations have been carried within a sufficient distance from
its end. Or the corrugations may extend throughout the entire length of the
tube. I may also provide similar automatic means whereby the rollers F are
permitted to move away from the tube at intermediate points in its length so that
the tube may remain uncorrugated at those points. The full depth of the corruga-
tion need not be formed in one operation but the tube may be worked backward

page_text: and forward in the die formed by the rollers F and the corrugations formed by such
a series of operations.
Instead of moving the tube relatively to a headstock provided with corrugating-
rollers the tube may be held stationary by any suitable means and the said
headstock moved along it.
The mandrel within the tube need not extend in the tube for any considerable
portion of the length of the said tube but may be of short length and be retained
within the tube by means of a rod in such a manner that it shall always be situated at
a point in the tube between the corrugating-rollers, whether the said rollers move
relatively to the tube or rice versa.
The mandrels employed may be collapsable, if desired, so that they may be
very readily withdrawn from the finished tubes, It is obvious that by this process
spiral grooves may be formed upon a tube either by giving the tube rotation about
its axis while it passes between rollers such as are hereinbefore described, or by
giving the frame in which the said rollers are held, rotation relatively to the tube,
as may be most suitable. The said spiral grooves like the straight grooves, may
be either interrupted or uninterrupted.
I do not limit myself to the use of any particular form of apparatus in the
manufacture of my improved tubes as such tubes can be manufactured in any con-
venient manner. I may form uninterrupted or interrupted corrugations in flat
sheets of metal for example and make such corrugated sheets into tubes in any
convenient manner.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
First. The herein described method of longitudinally corrugating tubes by
means of a series of rollers and a suitably shaped mandrel substantially as and for
the purpose specified.
Second. A tube corrugated longitudinally substantially in the manner and for
the purposes specified.
Third. A tube consisting of corrugated and plain portions substantially as and
for the purposes specified.
Fourth. A series of adjustable rollers arranged substantially as described with
reference to the accompanying drawing and operating to produce longitudinal
corrugations in a tube passed between them, for the purpose specified.
Fifth. The herein described apparatus or machine for longitudinally corrugating
tubes, constructed and operating substantially as described.
Dated this 14th day of December 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.