Improvements in the Construction of Furnaces and Flues for Steam Boilers.
Year: 1891

page_text: Date of Application, 6th Nov., 1891
Complete Specification Left, 2nd Aug., 1892-Accepted, 3rd Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Furnaces and Flues for
Steam Boilers.
I, WILLIAM HENRY WOODTHORPE, of 225 Barry Road, East Dulwich in the
County of Surrey, Engineer, do hereby declare the nature of this invention to be
as follows:-
:-
"
My invention consists of constructing furnaces and flues of steam boilers of
plates of such form that, when completed, the furnace or flue consists of a series
of frustrums of hollow cones or conoids of metal (preferably, mild steel) of
approximately uniform thickness, placed so that their axes lie in one straight line,
and having each of the conical or conoidal frustrums, at its largest diameter,
connected to the adjacent frustrum, at its smallest diameter, by suitable "belts
of metal, the metal in both belts and frustrums together being continuous and
having a continuous surface on either side of the completed furnace or flue. These
connecting belts have their transverse sections enclosed between the circumferences
of circles whose centres lie on the straight line joining the axes of the conical
or conoidal frustrums and their longitudinal sections are bounded, on both the fire
and the water side of the plate by curves or lines so disposed that the thickness of
the metal contained between the two surfaces of the belt at any part is greater
than that of the conoidal or conical frustrums to the extent necessary to give the
necessary strength to the furnace or flue.
A furnace or flue constructed in this way can have the plate forming it united
by a riveted joint or by welding. I do not bind myself to the diametrical
proportions of the conical or conoidal frustrums nor to the number or thickness of
the belts connecting them, as these may be varied.
By this construction the resistance of the furnace or flue to external fluid
pressure is very great, and the belts of metal, which are of greater thickness than
the conical or conoidal portions, are situated at parts of the furnace-crown which
are least subject to the impact of flame or of the heated gases. The furnace-
crowns are not likely to crack nor to harbour deposit &c. and they are of a form
which provides for expansion and permits the operations of scaling &c. to be
readily performed. On the fire-side of the plate the form is such as to promote
the mixing of the heated gases which are produced by the combustion of the fuel
and to insure their intimate contact with the thinner portions of the furnace plate :
the "steaming" qualities of the furnace or flue will, accordingly, be most
satisfactory.
When very long flues have to be constructed, the coned form admits of the
component lengths being conveniently fitted and connected together.
DL
W. H. WOODTHORPE.
COMPLETE SPECIFICATION.
Improvements in the Construction of Furnaces and Flues for
Steam Boilers.
I, WILLIAM HENRY WOODTHORPE, of 54 Oakhurst Grove, East Dulwich in
the County of Surrey, Engineer, (formerly of 225 Barry Road, East Dulwich)
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 :-
My invention consists of constructing furnaces and flues for steam boilers of

page_text: or
tr
"
plates of such form that, when completed, the furnace or flue consists of a series
of frustrums of hollow cones or conoids of metal (preferably, mild steel) of
approximately uniform thickness, placed so that their axes lie in one straight line,
and having each of the conical or conoidal frustrums, at its largest diameter,
connected to the adjacent frustrum, at its smallest diameter, by suitable "belts'
bands" of metal, the metal in both belts and frustrums together being con-
tinuous and having a continuous surface on either side of the completed furnace or
flue. These connecting belts, or bands, have their transverse sections enclosed
between the circumferences of circles whose centres lie on the straight line joining
the axes of the conical or conoidal frustrums and their longitudinal sections are
bounded, on both the fire- and the water-side of the plate by curves or lines_so
disposed that the thickness of the metal contained between the two surfaces of a
belt at any part is greater than that of the conical or conoidal frustrums to the
extent necessary to give the required strength to the furnace or flue.
On the accompanying sheet of drawings I have shown three figures, each
representing a longitudinal section of a portion of a furnace or flue of the general
form described by me.
In Figure 1 the thickened bands or belts of metal join hollow conical frustrums
and in Figures 2 and 3 hollow conoidal frustrums are joined by similarly thickened
bands or belts.
It will be observed that the smaller end of the conical or conoidal frustrum is
joined, by means of the thickened band or belt, to the larger end of the adjacent
frustrum.
In each drawing I have marked letters of reference and dotted lines near thereto.
and the thickened bands, or belts, are the portions extending between those
indicated by the letters A and B, and the conical or conoidal portions, previously
referred to, extend from B to C in the respective figures.
The drawings, which are made half-size, represent sections in which the hollow
conical or conoidal frustrums are about half-an-inch in thickness.
I do not,
however, bind myself to the diametrical proportions of the conical or conoidal
frustrums nor to the number, form nor area of section of the thickened bands or
belts as it is obvious that these may be varied.
The arrow, shown on each of the drawings, indicates the direction of the heated
gases on their way to the chimney, and is shown on the fire-side of the plate.
A furnace or flue constructed in this way may be formed of a plate made to the
requisite section and bent round, the tube being afterwards completed by welding
or riveting at the longitudinal joint. In this case the plates may be formed in any
suitable manner as, for example, by rolling, suaging or by means of an hydraulic
press, as well understood. Otherwise, the furnace or flue may be made by rolling
a plate, thickened as necessary, bending into tubular form, welding the longitudinal
joint and afterwards corrugating to the finished section. The furnace or flue may
also be constructed without a longitudinal joint.
The furnace or flue may be formed at its ends and connected to the boiler by
any of the ordinary methods, and two or more lengths may be joined when a long
furnace or flue is required.
By this construction the resistance of the furnace or flue to external fluid
pressure is very great and the belts, or bands, of metal, which are of greater
thickness than the conical or conoidal portions, are situated at parts of the furnace
which are least subject to the impact of flame or of the heated gases. The furnace-
crowns are not likely to crack nor to harbour deposit &c. and they are of a form
which provides for expansion and permits the operations of scaling &c. to be
readily performed. On the fire-side of the plate the form is such as to promote
the mixing and combustion of the heated gases produced and to ensure their
intimate contact with the thinner portions of the furnace-plate: the "steaming
qualities of the furnace or flue will, accordingly, be most satisfactory. When very
long flues have to be constructed the coned form admits of the component lengths
being conveniently fitted and connected together.
"

page_text: I desire it to be understood that I do not claim broadly the construction of
furnaces and flues having conical corrugations, or having stiffening ribs which are
symmetrical about a vertical transverse plane, but
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 construction of steam-boiler furnaces or flues consisting as to their general
form of a series of frustrums of hollow cones or conoids alternating with, and
continuous with, belts or bands whose general thickness is greater than that of
the conical or conoidal frustrums, substantially as described, and as illustrated in
the accompanying sheet of drawings.
Dated this and dar of Avon 1000
W. H. WOODTHORPE.