Improvements in Metal Tubes for Boilers, Condensers, and the like.
Year: 1894

page_text: Date of Application, 1st N.v., 1894
Complete Specification Left. 23rd July, 1895-Accepted, 21st Sept.. 1895
I, WILLIAM BRUCE THOMPSON, of Ellangowan, Dundee, in the County of
Forfar, Scotland, Engineer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in metal tubes for boilers, condensers
and the like, the object being to increase their heat transmitting surfaces relative
to their bulk.
These objects are attained by forming.on.each tube a series of open longitudinal
corrugations or furrows of V, U, or other suitable shape; these corrugations
being so disposed as to allow of the liquids or gases which surround or pass
through such tubes being in contact with metal of normal thickness, that is to say
the corrugations are not so narrow as to have two thicknesses of metal in contact.
The tubes may be manufactured in any known way, that is to say they may be
drawn from the solid, without being welded, or they may be corrugated while
being rolled from the strip, then curved around their lougitudinal axis and welded
to form a tube, or the tube may be plain and then indented with longitudinal
grooves.
Dated this 31st day of October 1894.
GEO. C. DOUGLAS & Co.,
41 Reform Street, Dundee, Agents for Applicant.
Improvements in Metal Tubes for Boilers, Condensers, and the like.
I, WILLIAM BRUCE THOMPSON, of Ellangowan, Dundee, in the County of
Forfar, Scotland, 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 :-
This invention relates to improvements in metal tubes for boilers, condensers
and the like, the object being to increase their heat transmitting surfaces relative
to their bulk.
And in order that my said invention aud the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended two explanatory sheets of drawings in which the same reference letters
are used to indicate corresponding parts in all the figures where shown.
Figures 1. 2. 4. 6. 7. and 8. (Sheet 1.) are cross-sections of tubes,. those
illustrated by Figures 1. 2. 4. and 6. being intended for use in steam boilers,, and
Figures 7. and 8. for condensers.
Figures 3. and 5. (Sheet 1.) give external side views of a tube, showing how the
corrugations terminate before reaching the ends.
Figure 9. (Sheet 2.) is a part side elevation of a machine for corrugating the
tubes, Figure 10. being a cross-section of same at A., A. looking in the direction of
the arrow B.

page_text: The aforesaid objects are attained by forming on each tube a series of open
longitudinal corrugations or furrows 11. of V, U, or other suitable shape; these
corrugations being so disposed as to allow of the liquids or gases which surround
or pass through such tubes being in contact with metal of normal thickness, that
is to say the corrugations are not so narrow as to have two thicknesses of metal in
contact. The tubes may be manufactured in any known way, that is to say they
may be drawn from the solid, without being welded, or they may be corrugated while
being rolled from the strip, then curved around their longitudinal axis and welded
to form a tube, or the tube may be plain and then indented with longitudinal
grooves.
In some cases, as illustrated by Figures 1. 3. and 5. the plain tube may be
selected of larger diameter than the holes in the tube plate, and the corrugations
then made, these preferably terminating before reaching the ends. These circular
ends are then drawn and compressed to the correct diameters of the holes in the
tube plates and cut to give the required length of tube. Sometimes the tubes are
selected of a diameter about equal to the hole in one tube plate and the corru-
gations then made, such corrugations terminating as previously described. The
ends of the tubes are enlarged somewhat, either before or after the formation of
the corrugations, and are afterwards turned slightly tapered to fit the holes in the
tube plate, the one end being smaller in diameter than the other, in order that
such tubes may, in the known way, be readily fitted into position or withdrawn.
The condenser tubes may be corrugated similarly, or they may have the corru-
gations extending from end to end.
A machine for forming the corrugations is illustrated by Figures 9. and 10.
12. is a part view of the frame of the machine, and 13. is a fixed bracket for
carrying the mandril rod 14, in this manner keeping the mandril 15. in its correct
relation to the rollers 16, 17. being a fixed standard for carrying these rollers.
18. is a sliding table on which are the brackets 19, such brackets carrying the
hollow centres 20. One or both of these brackets may be made adjustable, that
is to say they may be made to slide along the longitudinal axis of the machine
to some extent. 21. is a ring provided with a series of incline planes 22. oue for
each roller. The rollers are carried by sliding pieces 23, such pieces being
actuated by partially rotating the ring 21, thus causing the incline planes 22. to
act upon them. The sliding table 18. is made to reciprocate by means of the
rack 24, pinion 25, and other known appurtenances not shown in the drawings, the
combination working in a manner similar to a planing machine.
The machine is operated as follows:-One or both of the brackets 19. are
sufficiently drawn apart to enable a tube to be placed between the hollow
centres 20, the mandril 15. being within such tube, and the rollers 16. outside.
The brackets 19. are then advanced until the centres 20. hold the tube firmly,
that is to say the tube is held in a similar manner to that which obtains
when placing a tube in a lathe preparatory to turning it. The rollers are then
pressed against the tube, it being supported by the mandril 15, and the table 18.
is made to traverse, in this manner causing the tube to move backwards and
forwards until it is sufficiently corrugated.
In some cases the rollers 16. press on the tube at such a time that the mandril
rod 14. is in tension, no work being done on the tube on the return stroke, in order
that such rod may not buckle.
The table is then stopped, the centres 20, and the rollers 16, drawn apart and
the tube withdrawn.
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.) The use of the various types of corrugated tubes, substantially as described
and for the purposes set forth.

page_text: (2.) The mode of manufacturing corrugated tubes from tubes of a larger
diameter, then crushing, drawing and cutting the tubes to the required length,
substantially as described.
Dated this 20th day of July 1895.
GEO. C. DOUGLAS & Co.,
41 Reform Street, Dundee, Agents for Applicant.