Improvements in Steam Boilers.
Year: 1891

page_text: COBIT LETE SPECIFICATION.
Improvements in Steam Boilers.
I, JOHN FELL, of 149, Albert Road, Heeley, Sheffield, Engineer, 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 in
writing, and on reference to the accompanying sheet of drawings:-
This invention relates to the construction of improved internal flues for steam
boilers the object of my improvements being the imparting of greater strength and
durability to such flues.
In order that my invention may be fully understood it is illustrated on the
accompanying sheet of explanatory drawings the same being marked with figures
and letters of reference corresponding with the following description.
Figure 1, on the drawing is a sectional elevation of a steam boiler and one of
my improved internal flues in it, showing the general arrangement and fitting of the
flanged plates of which the flue is made.
Figure 2, is a section of part of a steam boiler flue showing a double flanged
belt or zone to which the plain cylindrical plates of the flue are attached by
rivetting.
Figure 3, is a section of a steam boiler flue showing it as made of a series of
cones or conically shaped plates rivetted together.
Figure 4, is a section of a conical steam boiler flue showing it as made with its
circular seams overlapping at an angle and rivetted together.
And Figure 5, is a section of a conical flue showing it as made with flanges each
Hange being formed entirely on the smaller end of each cone.
The first part of my improvements is applicable to the parallel flues of steam
boilers as usually constructed with a lap joint or joints, and it consists in having a
flange a, formed on the front end of each flue plate and being situated externally
at right angles so that each circular seam b, will have on it a strengthening flange a,
as shown at Figure 1, on the drawing. The flange can be further strengthened if
desired by rivetting or attaching thereto either an angle iron or a T iron, or a
flat or other ring the ring being bolted or rivetted through the flange.
Or, if deemed sufficient, alternate seams only of the flue plates can be flanged,
according to the pressure at which the boiler is required to be worked.
Or, as a modification of this part of my invention, the boiler flue can be con-
structed of plain cylindrical plates having rivetted thereon a double flanged belt or
zone c, (see Figure 2,) to which each plate is rivetted or attached by an ordinary
lap seam.
The advantage of the cylindrical flanged flue, shown at Figures 1, and 2, is,—that
it gives the longitudinal strength of an ordinary flue with its simplicity of construc-
tion, and additional strength to resist collapse, such additional strength being due
to the addition of the flanges.
The second part, or further modifications, of my improvements relates to and
consists in constructing the boiler flue of a series of cones or conical plates d, of
similar form, in which the larger end is flanged inwards with a reverse curve as
shown at e, Figure 3, the edge forming a plain lap into which the smaller end f, of
the adjoining similar cone is fitted and rivetted as in the ordinary parallel boiler
flue. Or the flange can be formed on each end of the cone by rolling the larger
end inwards to a radius struck from the inside and the smaller end outwards to a
radius struck from the outside, the edges of which must be of such diameters as to
overlap and form a seamy, as shown at Figure 4, standing at an angle of about
45 degrees at the intersection of the reverse curves. Or the flange can be formed
on the smaller end h, as shown at Figure 5, by rolling the plate outwards in
reversed curves so as to fit the internal diameter of the larger end of the cone.

page_text: The advantage of my conical, or vase-shaped, flues is, that increased safety is
gained for high pressures, and in case of shortness of water the area first becoming
bare is reduced the parts covered with water retaining the circular form and
effectually preventing collapse or rupture.
I would here have it understood that in carrying out my invention in practice I
do not confine myself to the exact conical form of the flues as shown in the figures
of the drawing but I may vary the contour of the flange by rolling outwards in
excess of the plain diameter while at the same time the flange will be contracted to
the diameter of the smaller end of the cone; or instead of flanging the flue plates
I may roll a separate flange to which the plain conical plates can be rivetted in the
ordinary manner.
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 :-
1. Constructing the internal flue, or thues, of a steam boiler of plates made with
flanges on their lap ends, substantially as described and as illustrated in Figure 1,
of the accompanying sheet of drawings.
2. The application and use of a double flanged belt or zone rivetted or attached
to the cylindrical plate or plates of a steam boiler flue when required for strenth-
ening the plates, as illustrated in Figure 2, of the accompanying sheet of drawings.
3. Constructing the internal flue or flues of a steam boiler of a combination of
cones or conically shaped plates arranged and fitted together, substantially as
described, and as illustrated in Figures 3, 4, and 5, of the accompanying sheet of
drawings.
Dated this 14th day of February 1891.
BRISTOW HUNT, R.P.A.,
Aldine Chambers, Sheffield, Agent for the Applicant.