IMPROVEMENTS IN MAKING BOILER TUBES
Year: 1877

page_text: LETTERS PATENT to John Tannahill, Tube Work Manager to Messieurs James
Eadie and Sons, of Rutherglen, in the County of Lanark, North Britain, for
the Invention of "IMPROVEMENTS IN MAKING BOILER TUBES."
PROVISIONAL SPECIFICATION left by the said John Tannahill at the Office
of the Commissioners of Patents on the 3rd April 1877.
JOHN TANNAHILL, Tube Work Manager to Messieurs James Eadie and Sons, of
Rutherglen, in the County of Lanark, North Britain. "IMPROVEMENTS IN MAKING
BOILER TUBES."
This Invention relates to an improved mode of making boiler tubes of malleable
iron or steel, and with one or both ends of copper or brass to serve as an ad-
vantageous and economical substitute for tubes made entirely of copper or brass.
In carrying out the Invention the copper or brass end is made with a conical
taper to enter a conical socket formed for it in the end of the iron or steel tube,
but the taper and conical surfaces are formed so as to have a slight space between
them, except at the inner end of the joint. The extreme end of the iron or steel tube is
expanded to form a lip to receive the soldering metal or alloy, and the tube is held
in a vertical position with the copper or brass end uppermost whilst being brazed
or soldered. It is preferred to apply the soldering metal or alloy in the form of
brass wire wrapped round the copper or brass end, so as to be just within the
expanded end or lip of the iron or steel tube, but it may be applied in any other
convenient form. After the brazing or soldering operation is effected, the projecting
parts at the outside of the joint are turned off to render the external diameter of
the compound tube uniform.
If preferred the end of the iron or steel tube may be tapered to enter a conical
socket formed in the copper or brass piece; and the expanded part or lip is in that
case formed on the copper or brass piece whilst the brazing operation is performed
with the copper or brass end downwards, instead of the iron or steel part.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Tannahill in the Great Seal Patent Office on the 2nd October
1877.
JOHN TANNAHILL, Tube Work Manager to Messieurs James Eadie and Sons, of
"IMPROVEMENTS IN MAKING 5
Rutherglen, in the County of Lanark, North Britain.
BOILER TUBES."
My said Invention relates to an improved mode of making boiler tubes of
malleable iron or steel, and with one or both ends of copper or brass to serve as an
advantageous and economical substitute for tubes made entirely of copper or brass.
And in order that my said Invention and the manner of performing the same 1
may be properly understood, I hereunto append a Sheet of explanatory Drawings,
to be herein-after referred to, and representing my improved tubes in the pre-
In these
paratory and finished stages and apparatus used in making them.
Drawings the same reference numerals are used to mark the same or like parts
wherever they are repented.
of the
In carrying out my Invention, according to the mode which I prefer, I make the
copper or brass end with a conical taper, as shown in elevation in Figure
accompanying Drawings, and I make the end of the iron or steel tube with a
conical socket to receive the tapered part of the copper or brass tube, but the
tapered and conical surfaces are formed so as to have a slight space between thein,
except at the inner end of the joint. This space is most conveniently secured by
shaping the tapered part of the brass or copper tube G with a slightly recessed or
rebated surface 7 between the shoulder 8 and a narrow belt 9 at the end.
Figure 2 is a longitudinal section showing the copper or brass tube 6 inserted in
the conical mouth of the iron or steel tube 10. The extreme end of the iron or steel
tube 10 is expanded to form a lip 11 to receive the soldering metal or alloy, and the
tube is held in a vertical position with the copper or brass end uppermost whilst
being brazed or soldered. I prefer to apply the soldering metal or alloy in the
form of brass wire 12 placed round the copper or brass end 6, so as to be just within
the expanded end or lip 11 of the iron or steel tube 10, but it may be applied in
any other convenient form.
In the brazing or soldering operation the soldering metal or alloy 12 runs down
into the joint when it is melted, and afterwards the projecting parts are turned off
to render the external diameter of the compound tube uniform, as shown in the
longitudinal section Figuro 3.
Figures 4 and 5 are vertical sections, as at right angles to each other, of a simple
and convenient furnace arrangement, with which the brazing or soldering operation
required in forming my improved compound boiler tubes may be effected in a
uniform and satisfactory manner.
A. small furnace 13 is constructed with a hori-
zontal flue 14 leading from it, and through the top and bottom of this flue 14 holes
15 are formed for entering the tube 10, so that the joint may be subjected to the
fire gases passing along the fluc. A pit 16 is formed for receiving the lower end of
the tube, the tube being supported in a conical stirrup 17, which is guided upon a
rod 18, and has attached to it a chain 19, the upper end of which is connected to a
lever 20. The tube can by means of this lever 20 be adjusted with its joint in
a proper position in the flue 14; a sight hole 21 being provided in the side of
the flue to facilitate the proper adjustment of the tube, and for ascertaining when
the proper condition for effecting the brazing or soldering operation has been
attained.
If found preferable in any cases, the end of the iron or steel tube 10 may be
tapered to enter a conical socket formed for it in the copper or brass piece 6, and
the expanded part or lip 11 is in such cases to be formed on the copper or brass
piece whilst the brazing or soldering operation is to be performed with the copper
or brass end downwards, instead of the iron or steel part.
Having thus particularly described my said Invention, and the manner of

page_text: performing the same, I have to state that I do not restrict myself to the precise
details herein described or delineated, but that what I believe to be novel and original,
and claim as the Invention secured to me by the herein-before in part recited
Letters Patent is, the making of improved compound boiler tubes by uniting copper
or brass ends to iron or steel tubes in the improved manner hercin described and
delineated, and more particularly the application of the recess part (7) and the
lip (11), substantially as and for the purposes herein-before described.
In witness whereof, I, the said John Tannahill, have hereunto set my hand
and seal, this Twenty-ninth day of September, in the year of our Lord One
thousand eight hundred and seventy-seven.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JOHN TANNAHILL. (L.S.)