An Improved Method of Fixing Tubes in Marine, Locomotive, and other Boilers.
Year: 1890

page_text: Date of Application, 15th Apr., 1890
Complete Specification Left, 15th Jan., 1891-Accepted, 21st Feb., 1891
PROVISIONAL SPECIFICATION.
An Improved Method of Fixing Tubes in Marine, Locomotive,
and other Boilers.
I, GEORGE EDWARD HANSEN, of Rydal Mount, Cowes, Isle of Wight, Yacht
Builder, do hereby declare the nature of this invention to be as follows :-
This invention relates to an improved method of fixing the tubes in multitubular
boilers whereby they may be readily taken out and replaced for any purpose and
constitute more efficient stays for the ends of the boiler than do the plain tubes
fitted by means of a tube expander in the manner ordinarily adopted.
For this purpose I make the tubes of the required length having a short length
of screw thread formed at the outside at each extremity. In order that the strength
of the tube may be maintained I make the tubes of increased outside diameter
at each extremity the increase in diameter being equal to double the depth of the
screw thread.
In the end plates of the boiler I make a number of tapered screw holes according
to the number of tubes to be inserted and I fit in each of these tapered screw holes
a nut or ferrule having an outside tapered screw thread to engage in the tapered
screw hole and an inside screw thread to engage with the screw thread formed at
the extremity of the boiler tube which the nut or ferrule is to retain firmly in
position.
The nut or ferrule having a tapered external screw thread to engage in the
tapered screw hole may be screwed into the boiler plate sufficiently to make a
water tight joint without necessitating the employment of any packing. Otherwise
if the outside screw thread upon the nut or ferrule is made cylindrical then the
water tight joint can be obtained by the interposition of an asbestos or other suitable
washer.
After screwing the nuts or ferrules into position in the ends of the boiler each
engaging one of the screw ends of the tubes I apply to the inside ends of the tubes
a tube expander in the usual way to swell the tube so that the outside screw
thread upon the tube is closed into the inside screw thread in the nut or ferrule in
a manner to prevent leakage at this joint.
In the case of small boilers I dispense with the screw nut or ferrule and screw
the tubes direct into the end plates of the boiler, the screw holes in which are
tapered as previously described. The cylindrical screw ends of the tubes being
screwed into position in the tapered screw holes I apply a tube expander to the
Inside ends of the tubes and so swell the screw thread into the tapered screw holes
in the boiler plates thus making the necessary water tight joint.
Dated this 15th day of April 1890.
AYRTON & THOMAS,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Method of Fixing Tubes in Marine, Locomotive,
and other Boilers.
GEORGE EDWARD HANSEN, of Rydal Mount, Cowes, Isle of Wight, Yacht
Builder, 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 an improved method of fixing tubes in multitubular

page_text: boilers whereby they may be readily taken out and replaced for any purpose and
constitute more efficient stays for the ends of the boiler than do the plain tubes
fitted by means of a tube expander in the manner ordinarily adopted.
For this purpose I make the tubes of the required length having a short length
of screw thread formed at the outside at each extremity. In order that the
strength of the tube may be maintained notwithstanding the screw threads formed
at its extremities I make the tubes of increased thickness at their ends.
The method of fixing the tubes in the boilers is shown in the accompanying
drawings in all the figures of which the same or similar parts are indicated by
like letters of reference.
Figure 1 is a sectional elevation of a screw nut or ferrule.
Figure 2 is a sectional view of the screw nut or ferrule retaining the boiler tube
in position in the boiler plate.
Figure 3 is a view similar to that represented in Figure 2 but with the addition
of packing washers to ensure a water tight joint at the several junctions.
In the end plates of the boiler A 1 make a number of tapered screw holes B
according to the number of tubes to be inserted and I fit in each of these tapered
screw holes a nut or ferrule C having an outside tapered screw thread D to engage
in the tapered screw hole B and an inside screw thread E to engage with the screw
thread at the extremity of the boiler tube F which the nut or ferrule C is to retain
firmly in position.
The nut or ferrule C may be screwed into the boiler plate A. sufficiently to make
a water tight joint without necessitating the employment of any packing. Or a
modified construction of the ends of the tube F and the mut or ferrule as represented
in Figure 3 may be adopted employing washers, G. H. J. of asbestos or other suitable
material to ensure a water tight joint at the fittings.
After screwing the nuts or ferrules C into position in the end plates of the
boiler A each engaging one of the screw ends of the tubes FI apply to the inside
ends of the tubes a tube expander in the usual way to swell the tube so that the
outside screw thread upon the tube is expanded into the inside screw thread of the
nut or ferrule in a manner to prevent leakage at this joint when washers such
as G. H. J. are omitted as shown in Figure 2.
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 :-
The combination of a nut or ferrule C having an exterior and an interior screw
thread, a boiler tube having screw threads at its ends and a boiler plate having
screw holes to receive the nuts or ferrules C with or without employing packing
washers; all operating to provide a method of fixing such tubes in boiler plates
substantially as and for the purpose set forth.
Dated this 15th day of January 1891
AYRTON & THOMAS,
Patent Agents.