AN IMPROVED FLUE OR TUBE FOR STEAM- BOILERS
Year: 1880

page_text: LETTERS PATENT to John Addy Hopkinson and Joseph Hopkinson, both of
the Firm of J. Hopkinson & Co., of Huddersfield, in the County of York,
Engineers, for an Invention of "AN IMPROVED FLUE OR TUBE FOR STEAM-
BOILERS."
PROVISIONAL SPECIFICATION left by the said John Addy Hopkinson and
Joseph Hopkinson at the Office of the Commissioners of Patents on the 4th
August 1880.
JOHN ADDY HOPKINSON and JOSEPH HOPKINSON, both of the Firm of
J. Hopkinson & Co., of Huddersfield, in the County of York, Engineers.
"AN IMPROVED FLUE OR TUBE FOR STEAM-BOILERS."
Our Invention relates to an improved construction of steam boiler flue or tube,
and consists in forming the same of two or more corrugated tubes connected by
plain portions of tube, that is to say, instead of joining the corrugated portions
direct to each other, as heretofore practiced, and thereby forming one continuous
corrugated flue or tube, we insert between such corrugated portions an intervening
flue or tube having a plain surface.
There may be any desired number of these corrugated and plain portions
according to the required length of the boiler. The plain surface portions of such
flue or tube are designed for the admission and application of conical or other
forms of circulating water tubes for the purpose of promoting a more even tempe-
rature of water at the lower and upper side of such a combined form of tube or
flue than would otherwise exist.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Addy Hopkinson and Joseph Hopkinson in the Great
Seal Patent Office on the 3rd February 1881.
JOHN ADDY HOPKINSON and JOSEPH HOPKINSON, both of the Firm of
J. Hopkinson and Co., of Huddersfield, in the County of York, Engineers.
"AN IMPROVED FLUE OR TUBE FOR STEAM BOILERS."
Our Invention relates to steam-boiler flues or flue-tubes, and consists chiefly in
forming the same of two or more corrugated cylinders or tubes combined with
plain cylinders or tubes in such a manner that instead of joining the corrugated
portions or sections of tube directly to each other, as heretofore practised in the
construction of corrugated flue-tubes, and thereby forming one continuous
corrugated flue, we insert between every two of such corrugated portions an
intervening tube or portion having a plain or uncorrugated surface for the reception
of conical or other water-circulating tubes or pipes, that is to say, pipes used for
the purpose of promoting a more even temperature of water at the lower and
upper sides of such flue tubes or flues than would otherwise exist. Therefore by
our improved construction we obtain the strength of a corrugated flue combined
with great facility for providing the same with water-circulating pipes or tubes.
Our said Invention is illustrated in the accompanying Drawing, in which,
Figure 1 is a longitudinal vertical section of a steam boiler provided with our
improved flue tubes.
Figure 2 is a horizontal section of the same on a line above the said tubes.
Figure 3 is a transverse section of the said boiler on the line x, x, Figure 1,
and
Figure 4 is a similar view shewing the water circulating pipes or tubes arranged
in an inclined position.
Figure 5 is a longitudinal section of one of our improved tubes consisting of
corrugated and uncorrugated portions combined and rivetted together.
Figure 6 is a similar section shewing the tube provided with a conical water-
circulating pipe rivetted in the uncorrugated portion of the said tube.
Figure 7 is a plan or top view of the same.
Figure 8 is a transverse section on the line y, y, Figure 7.
Figure 9 is a longitudinal section of a tube similar to that shewn in Figure 5,
but with a narrower plain or uncorrugated portion.
Figure 10 is a similar view shewing the same provided with a water-circulating
pipe welded in the uncorrugated portion, and
Figure 11 is a top view of the same.
Figure 12 is a longitudinal section shewing a tube provided with another form
of circulating pipe.
Figure 13 is a top view of the same, and
Figure 14 is a transverse section on the line z, z, Figure 13.
a, a, are the corrugated portions, and b, b, the plain or uncorrugated portions of
our improved flue tubes. There may be any desired number of these corrugated
and plain portions or sections, according to the length of the boiler in which the
flue is to be placed; c, c, are the water-circulating tubes or pipes secured in such
plain portions. These pipes may be placed and secured in the flues, as shewn, or
in any other suitable manner.
It will be obvious that our object is not to construct a boiler flue or tube by
connecting two plain portions of tube to a corrugated tube forming the fire-box
only, as we are aware that a corrugated tube forming the furnace or fire-box of a
boiler has been already used in combination with a plain portion of tube in front
of the furnace to connect the same to the end plate of the boiler, and with an

page_text: ordinary plain or uncorrugated flue extending from the back or inner end of the
corrugated furnace throughout the entire length of the boiler, but according to our
said Invention we construct corrugated flue tubes with their corrugated portions
united by intervening plain portions in such a manner as to alternately present
corrugated and plain surfaces with such a number of the said plain surfaces as may
be deemed desirable for the insertion of the said water-circulating pipes, which
plain or smooth portions of the said flue or tube should not be wider than is
requisite for the insertion of the water-circulating pipes. By this construction we
produce a flue tube differing but slightly with regard to the extent of its corru-
gations from a completely corrugated flue, and at the same time provide for the
insertion of circulating pipes in such flues; and it will be seen that a complete
boiler tube or flue made according to our said Invention will have a plain or
uncorrugated portion between every two of its corrugated portions, except that in
some cases with respect to the ends of such flues which may be attached to the
boiler by either plain or corrugated portions, as desired.
Having thus fully described our said Invention, and the manner of performing
the same, we wish it understood that we claim,―
A boiler-flue or flue-tube consisting of two or more corrugated portions in
combination with the plain or uncorrugated portion or portions placed between the
said corrugated portions for the reception of water-circulating pipes, substantially
as above set forth.
In witness whereof, I, the said Joseph Hopkinson, for myself and on behalf
of the said John Addy Hopkinson, have hereunto set my hand and seal,
this Twenty-ninth day of January, in the year of our Lord One thousand
eight hundred and eighty one.
Witness,
HENRY H. LAKE,
8, Southampton Buildings,
London, W.C.
JOSEPH HOPKINSON. (L.S.)