Improvements in Fire Boxes and in the Application of Fire Boxes to Sectional Boilers.
Year: 1890

page_text: Date of Application, 28th Nov., 1890
Complete Specification Left, 31st July, 1891-Accepted, 5th Sept., 1891
PROVISIONAL SPECIFICATION.
Improvements in Fire Boxes and in the Application of Fire Boxes
to Sectional Boilers.
I, ISAAC SHIMWELL MCDOUGALL, of Thornleigh, Higher Broughton, Man-
chester, in the County of Lancaster, Chemist, do hereby declare the nature of this
invention to be as follows :-
My invention relates to an improved construction and arrangement of furnace or
fire box intended for application to sectional steam boilers and with the fire box
water space included in the circulation of the sectional boiler by convenient con-
nections, and further in the application of a separate water lined or jacketed fire
box or fire boxes to a special type of sectional boiler.
In carrying out the first part of my invention I construct a fire box consisting of
a furnace or flue tube to contain the furnace and an outer shell of a greater diameter
to contain the furnace tube connected to it by front and back end plates or flanges.
The connections of the front and back end I so arrange that when desired the
furnace or flue tube may be taken out for cleaning. This I may accomplish in
various ways but I prefer to rivet a flange formed at the front of the furnace tube
to the front end plate and I bolt or otherwise secure the outer edge of the front
end plate to an angle iron riveted to, or a flange formed upon, the outer shell. The
back end plate I rivet to the outer shell and I attach the flange of the furnace tube
to the end plate by studs and nuts or by screwed pins or other convenient fastening.
By this arrangement when it is desired to remove the furnace tube it is only
necessary to unscrew the nuts and set pins and pull it out when the incrustation
which forms on the furnace tube and fills up the annular or chambered space
between it and the shell may be readily detached. The end plates and flanges are
faced where required to make a pressure tight joint and suitable jointing material
may be adopted if necessary. By this device the furnace tube is readily removed
and replaced when clean. Several flues or furnaces may be attached to one shell
if found more convenient to be applied in this manner.
In carrying out the second part of my invention I apply a fire box or fire boxes
of the hereinbefore described construction with or without removable furnace tube
to that type of sectional boiler which consist of upper and lower vessels preferably
cylindrical, which vessels are connected by tubes such as those of the conical kind.
The fire box connects at its lower part with the lower vessel by suitable pipes with
intervening mud drums or drum if required and the upper part of the fire box
connects with the upper vessel and so the fire box water space is included in the
circulation. By this means a considerably increased economy is obtained.
Dated this 26th day of November 1890.
CLERK & MARKS,
13, Temple Street, Birmingham, Agents for Applicant.
COMPLETE SPECIFICATION.
Improvements in Fire Boxes and in the Application of Fire Boxes
to Sectional Boilers.
I, ISAAC SHIMWELL MCDOUGALL, of Thornleigh, Higher Broughton, Man-
chester, in the County of Lancaster, Chemist, 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 relates to an improved construction and arrangement of furnace or

page_text: fire box intended for application to sectional steam boilers, and with the fire box
water space included in the circulation of the sectional boiler by convenient con-
nections ; and further in the application of a separate water lined or jacketed fire
box or fire boxes to a special type of sectional boiler.
In carrying out the first part of my invention I construct a fire box consisting of
a furnace or flue tube to contain the furnace, and an outer shell of a greater
diameter to contain the furnace tube, connected to it by front and back end plates
or flanges. The connections of the front and back end I so arrange that when
desired the furnace or flue tube may be taken out for cleaning.
This I may
accomplish in various ways, but I prefer to rivet a flange former at the front of the
furnace tube to the front end plate, and I bolt or otherwise secure the outer edge
of the front end plate, to an angle iron riveted to or a flange formed upon the outer
shell. The back end plate I rivet to the outer shell, and I attach the flange of
the furnace tube to the end plate by studs and nuts, or by screwed pins or other
convenient fastenings. By this arrangement when it is desired to remove the
furnace tube, it is only necessary to unscrew the nuts and set pins and pull it out.
The incrustation which forms on the furnace tube and fills up the annular or
chambered space between it and the shell may thus be readily detached.
The end plates and flanges are faced where required to make a pressure tight
joint, and suitable jointing material may be adopted if necessary.
Referring to the two accompanying sheets of drawings illustrating my invention:
Figure 1 is a section through my separate water cased furnace and Figure 2 is
an end elevation.
Figure 3 shows in longitudinal section the application of my invention to a
Crosland type sectional boiler and
Figure 4 is an end view of Figure 3.
Figure 5 is a section as in Figure 1 to show my hollow protecting shield con-
taining water.
A is the furnace flue riveted by flange to the front plate E which plate is bolted
by bolts a to the shell B by means of a suitable angle iron or flange. The back
plate E is riveted by angle iron or flange to the shell B and the furnace tube A,
by a back flange is screwed to E¹ by means of the set pins or studs b. When the
bolts a and the set pins or studs b are taken out, then the tube C is free to be
pulled out and scale can be readily removed from its surface. As hereinbefore
stated the end plate and flanges are suitably faced to make a pressure tight
metal to metal joint or suitable packing may also be inserted. A semicircular
shield D is provided, which may be of cast iron or other suitable material, in order
to protect the set pins or studs b from the action of the flame. Or a water jacketed
shield may be provided as in Figures 5, 6 & 7 where the semicircular hollow
shield M connects to the water space by pipes of considerable area, as M³, M².
The water thus circulates rapidly through the hollow shield, and the set pins or
studs 6 are effectively protected. Suitably shaped fire bricks as N are built up
on M to further protect the set pins from the direct action of the flame. The
connections M¹ M², are so arranged that the shield M may be readily uncoupled
for cleaning. To facilitate this operation, I sometimes provide hand holes closed
with suitable doors to get at the nuts placed within the boiler to protect them
from the heat. The water jacketed shield and connections are of course constructed
strongly enough to withstand the full boiler pressure.
Figure 2 shows the end elevation of the furnace looking on the flange E and the
bolt holes a', a' etc. The application of my invention to a Crosland type of boiler
is shown at Figure 3 in longitudinal section, and in front end view at Figure 4.
The water space C (Figures 1 and 3) is connected to the upper drum J of the
boiler by the tube pieces F, F, and to the lower drum H by the connections G, G,
and intermediate pipe. The upper and lower drums J and H are connected by
water tubes K, K', K', K³, K, K³, shown in section and others as indicated.
perfect circulation is caused through the water chamber C, from H to J and thus
the chambered fire box materially adds to the power of the boiler. The hot gases
A

page_text: pass above the brick partition L then down and around the drum H before
discharging at the chimney.
By my invention the difficulties incident to the use of a water chambered fire box
are readily overcome, and the furnace tube A is rendered readily removable and
so enables the chamber C to be conveniently cleared from all deposited matter.
Although I have shown my removable furnace tube fire box as applied to a
Crosland boiler, yet. I do not restrict its application to this type as it may be
applied with equal advantage to other types of water tube boiler. In any type of
water tube boiler by this device the furnace tube is readily removed and replaced
when clean. Several flues or furnaces may be attached to one shell if found more
convenient.
Generally in applying my invention to any type of water tube boiler, the fire
box connects at its lower part with the lower vessel by suitable pipes, with
intervening mud drums or drum if required, and the upper part of the fire box
connects with the upper vessel, and so the fire box water space is included in the
circulation.
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) In water tube steam boilers the use of a separate water chamber fire box,
in which fire box the furnace flue is arranged to allow of removal and replacement
substantially as and for the purposes hereinbefore described and illustrated in
the accompanying drawings.
(2) The water chambered fire box in combination with a water tube boiler as
herein before described and illustrated at Figures 3 and 4 of the accompanying
drawings.
(3) The water chambered fire box hereinbefore described and illustrated at
Figures 1 and 2 of the accompanying drawings.
Dated this 30th day of July 1891.
CLERK & MARKS,
13, Temple Street, Birmingham, Agents for the Applicant.