Improvements in Furnaces for Steam Boilers.
Year: 1890

page_text: Date of Application, 21st Oct., 1890-Accepted, 22nd Nov., 1890.
COMPLETE SPECIFICATION.
Improvements in Furnaces for Steam Boilers.
I FRANCIS GORDON BATES of 2005 North College Avenue in the City of Philadelphia
State of Pennsylvania United States of America Mechanical 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:-
The object of this invention is to so construct a steam boiler furnace as to ensure
the effective combustion of the gases arising from the fuel to provide an extended
heating surface and to cause an effective circulation of the water from the lower to
the upper portion of the boiler.
I will describe my invention with reference to the accompanying drawings in
which :-
Figure 1 is a longitudinal section of a marine steam boiler of a well known type
embodying the invention.
Figure 2 is a view of the boiler partly in transverse section and partly in front
elevation.
Figure 3 is a sectional plan view of the boiler on the line 1-2 Figure 2 and
Figure 4 is a transverse section on the line 3-4 Figure 1.
A represents the outer shell of the boiler, which has, in the present instance, two
flues B, in the lower portion and a series of return tubes D, in the upper portion,
the tubes and flues being in communication with each. other through a combustion
chamber E at the rear as usual.
It will be understood however that the invention is applicable to boilers without
return tubes, and also to boilers having but a single flue, or more than two flues, if
desired.
In each flue B, at the front end of the same is a furnace, comprising three fire
places F, F, and G, the fire place G being located centrally between and on a lower
level than the fire places F, F, and extending through the flue is a central water
chamber H, which separates the side fire places from each other, and is forked at
the front portion so as to form depending legs on each side of the lower central fire
place G..
This central water chamber communicates through tubes a with the water space
of the boiler below the flue B, and the upper portion of the said water chamber
communicates through tubes b with the water space of the boiler above said flue,
so that an effective circulation of water from the lower portion of the boiler into
and through the water chamber and thence into the upper portion of the boiler, is
ensured, both the inner and outer walls of the water chamber being subjected to the
action of the products of combustion from the fire places, so as to be highly heated
thereby.
The products of combustion from the central fire place escape through a longi-
tudinal flue I, in the rear portion of the water chamber H and enter the combustion
chamber E, at the rear of the boiler, where they meet and mingle with the products
of combustion, from the side fire places, the entire volume of the products of
combustion then passing through the tubes in the upper portion of the boiler.
The rear end of the discharge flue I however, is provided with a damper d and
in the upper portion of the water chamber some distance in advance of the rear
end of the same, is a short vertical flue J, extending upward from the longitudinal
flue so that, by closing or partially closing the damper at the rear end of the flue I
any desired proportion of the products of combustion from the central fire place may
be caused to pass through this vertical flue J, and thus mingle with the products of

page_text: combustion from the side fire places, before said products reach the smoke box or
combustion chamber E at the rear end of the boiler."
Each of the fire places is accessible through an opening m in the front plate of
the boiler and has a suitable ash pit, access to which can be gained through an
opening n in said front plate and it is preferable that the ash pits of the side fire
places should be cut off from communication with the ash pit of the central fire
place, as for instance, by the use of filling slabs, as shewn by dotted lines in
Figure 2 so that the draught in each fire place may be regulated independently of
that in the others.
By firing in the fire places alternately the gases arising from each supply of fresh
fuel are caused to meet and mingle with the highly heated products of combustion
from the incandescent masses of fuel in the other fire places, and the thorough
combustion of all of the gases is thereby effected.
It will be observed that the improved furnace is so constructed that it can be very
readily used as a substitute for the ordinary internal or flue furnaces of marine
boilers, a few simple pipe connections being all that are necessary in order to apply
the fire places to the flue, hence, boilers of the present construction can be very
readily adapted for carrying out the invention.
In many cases, it may be advisable to supply the upper portion of the water
chamber, above the central fire place and its discharge flue, with a series of tubes
as shown in Figure 1 so as to provide communication between said fire place and
its flue, and the space above the water chamber and between the two side fire places.
The invention, although specially designed for application to marine boilers is not
limited to such use as the improved form of multiple furnace with central water
chamber can be used in the combustion chambers of other boilers, and the side fire
places may, in some cases, be used without the central fire place.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1st. The combination of the internal flue casing of a steam boiler with a furnace
consisting of opposite side fire places and a water chamber separating the same and
having, at top and bottom, pipe connections with the flue casing, whereby it
communicates with the water space of the boiler, substantially as hereinbefore
described.
2nd. The combination of the internal flue casing of a steam boiler, with a furnace
consisting of opposite side fire places, a central fire place, and a water chamber
separating the central fire place from the side fire places, and having, at top and
bottom, pipe connections with the flue casing, whereby it communicates with the
water space of the boiler substantially as herein before described.
3rd. The combination of the combustion chamber casing of a steam boiler, with a
furnace, comprising the opposite side fire places the lower central fire place, and a
water chamber interposed between said central and side fire places and forked at the
front end, so as to enclose the central fire place, said water chamber communicating
at top and bottom with the water space of the boiler substantially as hereinbefore
described.
4th. The combination of the combustion chamber casing of a steam boiler with a
furnace comprising the opposite side fire places and the central lower fire place and
a water chamber interposed between said central and side fire places and having a
rearwardly projecting flue extending from the central fire place, said water chamber
communicating at top and bottom with the water space of the boiler substantially as
herein before described.
5th. The combination of the combustion chamber casing of a steam boiler, the
opposite side fire places, the lower central fire place and the water chamber inter-
posed between the central and side fire places and communicating at top and bottom
with the water space of the boiler, said water chamber having a discharge flue for
the central fire place, and a vertical passage some distance in advance of the rear end

page_text: of the flue, and communicating with the space above the water chamber, substantially
as hereinbefore described.
1000
J. H. JOHNSON & Co.,
Agents.