IMPROVEMENTS IN TUBES OR FLUES FOR STEAM-BOILERS
Year: 1885

page_text: We, JOHN ADDY HOPKINSON and JOSEPH HOPKINSON, both of the firm of
J. Hopkinson & Co, of Huddersfield, in the County of York, Engineers, do hereby
declare the nature of our invention for IMPROVEMENTS IN TUBES OR FLUES
FOR STEAM-BOILERS "and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
Our invention relates to boiler tubes or flues of the class or type described in
the specification of Letters Patent granted to the said John Addy Hopkinson,
May 1st A D. 1883, No 2209.
The invention forming the subject of the said former Letters Patent is specified
as partly consisting "in so constructing the said flues or flue-tubes that separate
strengthening hoops, rings or flanges may be dispensed with and couical or other
water circulating tubes or pipes can be readily inserted and efficiently secured in
the said flue-tubes."
Our present invention is designed to so modify the construction of these tubes
that, while retaining the advantages above specified, we obtain further important
advantages, as will appear from the following description.
Our invention is illustrated in the accompanying drawing, in which we have
shewn, in longitudinal section, various forms or modifications of our improved
tubes or flues.
It will be seen that, in all of these examples or illustrations of our invention,
there exists the combination of three parts. or elements, viz -the bulbous formation
or configuration of the part a, the "Bowling hoop" or "Bowling ring" formation
of the part b, and the flange or flanged ends at c. And it is the combination, in one
homogeneous structure, of these three parts or elements in a flue or tube that
constitutes the essential feature of our invention. The aforesaid parts a and b,
which embody the bulbous configuration and Bowling hoop formation, are
duplicated, triplicated or otherwise multiplied in each tube or flue, as desired,
but, in all cases, they are produced in the tube integrally, and in combination, with
the flanges at the ends of the same.
Figures 1, 2, 3, 4, 5 shew examples of our tubes or tube-sections, in which the
construction is varied in respect of the number and relative position of the parts a
and b. Tube-sections constructed according to either of these modifications may
be united to form flues of any desired length.

page_text: Figure 6 shews the flue-tube of a boiler formed by rivetting together a suitable
number of these tubes or sections.
The combination of the aforesaid parts or elements, viz:-the bulbous portion,
the Bowling hoop portion, and the flanges, in the construction of our improved
flue, affords very important advantages, viz:-It enables us to obtain increased
strength, while providing for the connection of the said tube-sections to each other
as readily and conveniently as in the construction of an ordinary straight or
cylindrical flanged boiler-flue. Morcover, in boiler-flues heretofore constructed
with Bowling hoops or rings, the rivets in some portions of the Blue are exposed to
the action of the fire, but it is obvious that this condition does not exist in our
improved flue. Furthermore, the flanges, in combination with the bulbous and
Bowling hoop formation as above described, are free from the liability to fracture
at the root, as they frequently do in ordinary plain flanged boiler-flues. In
combination with our improved boiler-flues, we may use Galloway or other water-
circulating tubes arranged in the usual, or any convenient, manner.
We wish it distinctly understood that our invention is limited to metal tubes or
cylinders wherein the parts or elements, which we have termed the bulbous portion,
the Bowling hoop portion, and the flanges, constitute a single homogeneous or
undivided annular or tubular piece or structure, and to flues or flue-tubes formed
entirely, or partially, of such tubes or cylinders.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed we declare that what
we claim is
First. A tube or tube-section consisting of one homogeneous or undivided piece
which embodies in its structure the bulbous, the Bowling-hoop, and the flanged
formation or construction, as, and for the purposes, above described.
Second. A boiler-flue consisting, or partly consisting, of such tubes or tube-
sections united by their flanges, as above set forth.