Improvements in Forced Draught Apparatus for Steam Boiler Furnaces.
Year: 1892

page_text: Date of Application, 21st June, 1892
Complete Specification Left, 10th Feb., 1893-Accepted. 18th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in Forced Draught Apparatus for Steam Boiler
Furnaces.
I, JAMES HILL, of 5 Bellfield Street, Glasgow, Bricklayer and Furnace-
builder, do hereby declare the nature of this invention to be as follows:-
This invention relates to an apparatus for improving the draught and combustion
in steam boiler furnaces.
The
The invention consists in fitting in the ashpit and preferably below the furnace
bars one or more tubes, which, at their inner ends are inserted into the bridge.
Their outer ends project through the plate covering the front of the furnace.
fire bridge is made with one or more passage ways through it. The passage ways
are preferably covered with a thin silica brick or other roof. The passage ways
are so made as to deliver the air-blast in a highly heated state at the back of the
bridge where it impinges on the products of combustion passing to the flue.
Fitted in the outer ends of the pipes are one or more steam blowers. The
blowers induce a strong current or draught of air to pass into and through the
pipes.
Holes may be made at intervals in the length of the pipes through which air and
steam can escape into the ashpit and force its way through the furnace bars.
I prefer to use two pipes with a blower in each.
The air and steam supply can be regulated in any suitable manner.
In this invention the air and steam blast is heated to a very high degree whilst
passing through the passages in the fire bridge.
Dated this 20th day of June 1892.
H. D. FITZPATRICK,
Glasgow and London, Agent.
COMPLETE SPECIFICATION.
Improvements in Forced Draught Apparatus for Steam Boiler
Furnaces.
1, JAMES HILL of 5 Bellfield Street, Glasgow, Bricklayer and Furnace-
builder, 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 :-
This invention relates to an apparatus for improving the draught and combustion
in steam boiler furnaces.
And in order that my said invention may be properly understood, I have
hereunto appended an explanatory sheet of drawings, whereon
Fig. 1, is a longitudinal section of a boiler.
Fig. 2 is a cross section.
Fig. 3 is a sectional plan with fire bars removed.
Fig. 4 shows, in longitudinal section, a modified form of fire bridge.
Fig. 5 is a section on the line x-x, Fig. 4.
Referring to the drawings whereon the same reference letters, wherever repeated,
indicate similar parts.
a is the boiler shell. b, b¹ the furnaces. c the fire bridge. d the fire bars.
e ash-pit. f the flue.
In carrying out my invention I may fit in the ashpit e and, preferably, below the
furnace bars d, one or more, preferably two, tubes g, which, at their inner ends, are
I Price ed

page_text: inserted into the bridge c and at their outer ends project through the plate covering
the front of the furnace.
The fire bridge is built of bricks and has passages h, shown dotted, leading from
the tubes g to horizontal passage ways i which are open at their back ends. There
may be three or other number of passage ways in each bridge, as shown at
Figs. 2 and 3, and these passage ways may be connected together by a cross
passage way j. A, preferably, larger vertical passage way k leads from the top of
the bridge down to one or more, preferably three, horizontal passage ways / below
the passage ways i.
The passage ways are, preferably, covered with a roof of thin silica brick or
other refractory material.
Steam or air blowers m may be fitted so as to deliver jets of steam or air into
the tubes g.
As the hot gases from the furnace pass through the passages k and I as well as
over the bridge it is, as a consequence, very highly heated.
The air and (or) steam passing through the tubes g, and the bridge c is highly
heated when it escapes at the back of the bridge e and impinges on the products of
combustion passing over and through said bridge. The mixture of the hot air
with the gases greatly promotes combustion and reduces smoke.
The blowers, if steam jets, induce a strong current of air to pass into and through
the pipes g.
In many classes of furnaces I find it advantageous to dispense with the tubes g
and blowers and to merely allow air from the ash pit to pass naturally through the
passage ways h, i in the bridge in order to promote the combustion and reduce the
smoke.
Instead of building the bridge as shown at Figs. 1, 2 and 3 it may be built in
the manner shown at Figs. 4 and 5. In this case the passages i are longer and the
vertical passage is further back and between the passages i, (see Fig. 5). The
front of the bridge is supported on a metal or other arch m¹ so that air from the
ash pit has a free passage from the space n to the channels i.
Holes may be made at intervals in the length of the pipes 9 through which
air and steam can escape into the ashpit and force its way through the furnace
bars.
The air and steam supply can be regulated in any suitable manner.
The construction of the bridge can be further altered to suit different require-
ments without departing from the principle of the invention.
My improvement can be adapted and applied to any suitable form of land or
marine boiler furnace.
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. A fire bridge of a boiler constructed with passage ways for air and hot gases,
substantially as and for the purposes hereinbefore set forth.
2. The combination with the improved fire bridge with its passage ways (k,l and i)
for air and hot gases, of draught tubes g, substantially as hereinbefore described
and shown on the drawings annexed.
Dated this 9th day of February 1893.
H. D. FITZPATRICK,
Glasgow and London, Agent.