IMPROVEMENTS IN AND RELATING TO FLUES OR FLUE-TUBES FOR STEAM BOILERS
Year: 1883

page_text: LETTERS PATENT to John Addy Hopkinson of the Firm of J. Hopkinson
& C° of Huddersfield, in the County of York, Engineer for an Invention of
PROVISIONAL SPECIFICATION left by the said John Addy Hopkinson at.
the Office of the Commissioners of Patents on the 1st May 1883.
JOHŃ ADDY HOPKINSON of the firm of J. Hopkinson and Co of Huddersfield,
in the County of York, Engineer, "IMPROVEMENTS IN AND RELATING TO FLUES
OR FLUE-TUBES FOR STEAM BOILERS
"
My invention relates to flues or flue-tubes for steam boilers, and one part of my
said invention consists in so constructing the said flue-tubes that strengthening
hoops or flanges may be dispensed with and conical or other water circulating
tubes or pipes can be readily inserted, and efficiently secured in the said flue-tubes.
Another part of my invention which is applicable generally to flues having
circulating pipes is designed to provide means whereby the flame and heated
products of combustion will be more effectually caused to impinge upon the sides
of the flue-tubes and of the said circulating pipes than is the case with flue-tubes
as heretofore made.
My improved fue tube is made with one or more longitudinally curved or
bulbous portions, the curve being preferably a segment of a circle. At one end or.
at each end of the said curved portions is formed a ring, somewhat resembling a
so called "bowling" hoop but integral with the flue-tube, instead of being rivetted
thereto. The circulating pipes are inserted at the curved portions and may be
rivetted or welded in the ordinary manner. By constructing the flue-tubes in
this manner I impart great strength to them and in joining two lengths of tube
only one line of ring seam rivets is required instead of two as with hoops applied
in the ordinary manner.
In order to increase the heating effect in the flue, I provide in combination with
one or more of the circulating pipes, semi-circular or other suitably shaped plates
which serve as baffle or heat distributing plates, the said plates closing the fluo

page_text: with the exception of a passage on each side of the circulating pipe and other
passages between the inner circumference of the flue-tube and the edges of the said
plates. These plates are pivoted in such a manner that they can be adjusted to.
regulate the area of the passages or can be turned so as to lie parallel with the
axis of the flue-tube to permit a man to pass through the latter on either side of
the circulating pipe. In carrying this part of my invention into practice according
to one method, after the said circulating pipes are inserted and secured in the
flue-tubes I fit upon them the devices hereinafter described that is to say I provide
two rings or annular clamps of cast iron or other suitable material formed in two
pieces so that they can be fitted upon the said circulating pipes and secured by
bolts and nuts or cotters These clamps are each made with apertures or recesses
to receive projections on the ends of the said plates thus forming hinges for the
same. The said baffle plates may be made of cast iron, brick, tile or other suitable
material. It is obvious that I can apply this part of my said invention to the
flues of existing boilers in which circulating tubes are employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Addy Hopkinson in the Great Seal Patent Office on the
19th October 1883.
$5
JOHN ADDY HOPKINSON, of the firm of J. Hopkinson and C, of Huddersfield,
in the County of York, Engineer, IMPROVEMENTS IN AND RELATING TO FLUES
OR FLUE-TUBES FOR STEAM-BOILERS
"
My invention relates to flues or flue-tubes for steam boilers.
One part of my
said invention consists in so constructing the said flue-tubes that separate
strengthening hoops, rings or flanges may be dispensed with and conical or other
water-circulating tubes or pipes can be readily inserted and efficiently secured in
the said flue-tubes. Another part of my invention, which is applicable generally
to flues having transverse circulating pipes, is designed to provide means whereby
the flame and heated products of combustion will be more effectually caused to
impinge upon the surfaces of the said flues and circulating pipes than in any
heretofore known or existing arrangements of such flues and pipes.
According to my invention I construct a flue-tube with one or more longi-
tudinally protuberant, bulbous or convex portions, that is to say, with a portion
or portions whereof the longitudinal section is delineated by convex lines, the
curves being preferably segments of a circle. At one end (in some instances at
each end) of the said curved portion is a ring, somewhat resembling in appearance
a so called "Bowling" hoop, but made integral with the flue-tube instead of being
rivetted thereto. The circulating pipes are inserted in the largest part of the said
protuberant or curved portions and are rivetted, welded or otherwise secured in

page_text: the same. By constructing the flue-tubes in this manner I impart to them great
strength, and in joining two lengths of tube I require only one line of ring seam
rivets instead of the two lines of such rivets which are required with hoops applied
in the ordinary manner.
To increase the useful effect of the heat in the flue, I provide, in combination
with one or more of the circulating pipes, devices which I term baffle-plates, that
is to say, semi-circular or other suitably shaped plates which serve to retard and
distribute the heat; the said plates are so formed that they occupy the greater
part of the cross sectional area of the flue; so that they will close the flue with
the exception of passages or spaces hereinafter described. But the said plates are
fitted to turn upon or around or partially around the circulating pipes so that they
can be adjusted to regulate the area of the flue-space, or can be set parallel with
the axis of the flue-tube to permit a man to pass through the latter on either side
of the circulating pipe.
My improvements are illustrated in the accompanying drawing, in which.
Figure 1 is a longitudinal section of a tube to serve either as a boiler furnace or
flue or any part thereof
Figure 2 is a longitudinal section of a similar tube provided with a transverse
circulating pipe.
Figure 3 is a longitudinal section of a flue-tube constructed with two protuberant
or bulbous portions, and rings or hoops formed integrally therewith, the said tube
being provided with transverse circulating pipes. Figures 3ª, 3b, illustrate
modifications in the construction of these tubes.
Figure 4 is a longitudinal section of a flue with a circulating pipe fitted with
the aforesaid baffle-plates.
Figure 5 is a transverse section of Figure 4.
Figure 6 is a side view illustrating a modification in the construction of these
baffle plates.
Like letters indicate the same parts throughout the drawing.
a, a are the protuberant or bulbous portions of the tube; b, b are the rings or
hoops formed integrally with the same; c, c are the ends or plain portions through
which are passed the rivets for uniting these tubes when two or more of them are
required to form a boiler flue. In the form of tube shown in figure 3* the ends are
constructed to make what we term a thimble-lap joint which may be rivetted or
welded. By our improved construction we obviate the necessity of providing at
the ends of the bulbous portions of the tubes flanges which would be always liable
to fracture at the angles by the expansion and contraction of the flue. Figure 3b
which is drawn to a reduced scale shows a complete boiler flue consisting of tubes
formed as in Figure 3* At d d are shewn the transverse circulating pipes, and
at e, e the baffle-plates mounted thereon.
To support these plates I provide two rings or annular clamps f of cast iron or
other suitable material formed in two pieces so that they can be conveniently
fitted upon the circulating pipes d and secured by bolts and nuts or cutters. These
clamps f are made with holes or recesses to receive projections 9 on the said plates
which are thus provided with pivots or hinges. The said baffle-plates e may be
made of cast iron, brick, fire clay, tile, asbestos or other suitable material.
The said pivots permit each plate to be turned upon its axis so as to present it
to the action of the heated gases at any desired angle and also permit it to be
adjusted for enabling any person employed in cleaning the flue to turn the baffle
plates parallel with the axis of the flue so that he can pass conveniently through
the flue at the side of the said baffle-plate.
I prefer that the said baffle-plates should be so constructed and arranged as to
leave a space between their straight or inner edges and the circulating tubes on
which they are mounted, to allow the heated gases to come in contact with the said
circulating tubes and to pass between the same and the plates, so as to economize
to the fullest extent the thoroughfare of heat, for evaporative duty.
The manner of fixing or mounting the said baffle-plates may be varied, but

page_text: preferably when the plates are formed of brick or like material I adopt the
construction shewn in Figure 6, in which the plate has around its periphery a
groove or recess into which I fit an encircling metal band, strap or holdfast
provided with pivots g for mounting it on, or attaching it to, the rings or clamps f
at the upper and lower portions of the circulating pipe. The flanges enclosing the
groove in the baffle plate, if extending around its entire periphery, shield the
metallic strap or holdfast from the action of the flame or heated gases.
In some instances I secure the said baffle-plates to the rings or annular supports
by passing bolts through holes extending from their outer to their inner sides, the
said bolts being screwed into a metallic piece adjoining the circulating tube; or
I may adopt any other convenient manner of securing the said plates and
supporting them upon the said rings so that they will be adjustable with or upon
the same.
It is obvious that I can apply this part of my said invention to the flues of
existing boilers in which circulating tubes are employed.
Having thus fully described my said invention and the manner of performing
the same I wish it understood that I do not claim generally the use, in a boiler-
flue, of plates for baffling or obstructing the passage of the heat as I am aware
that such devices have been employed although not in combination with the
circulating tubes as herein described, but I Claim :-
First. Å furnace or flue tube consisting of one or more protuberant, bulbous or
longitudinally convex portions having a ring or hoop formed integrally therewith
at one or both ends or between two or more of such bulbous portions, substantially
as, and for the purpose, specified.
1
Second. A heat-distributing or baffling device consisting of a plate or plates of
metal, fire clay, asbestos, brick or other suitable material mounted adjustably on a
circulating pipe, substantially as, and for the purposes, specified.
In Witness whereof I the said John Addy Hopkinson have hereunto set my
hand and seal this Second day of August in the year of Our Lord one thousand
eight hundred and eighty three.
JOHN ADDY HOPKINSON