Improvements in and connected with Steam Boiler Furnaces.
Year: 1896

page_text: Date of Application, 4th Sept., 1896-Accepted, 10th Oct., 1896
COMPLETE SPECIFICATION.
Improvements in and connected with Steam Boiler Furnaces.
1, JAMES HILL of 579 Gallowgate, Glasgow, 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 has for its object to promote the draught, improve the combustion,
and lessen the smoke in the furnaces of steam boilers, and, also, in certain cases, as
hereinafter explained, to improve the method of firing.
And in order that my said invention may be properly understood I have
hereunto appended, by way of example, an explanatory sheet of drawings showing
my invention as applied to a Lancashire boiler adapted to be heated by gas
or coal.
Fig. 1 is a front view with part in section.
Fig. 2 is a longitudinal section.
Fig. 3 is a cross section on the line - Fig. 2, and
Fig. 4 is a plan on the line Y-Y Fig. 2.
In carrying out my invention for boiler furnaces wherein it is desired to improve
the draught, promote combustion, and reduce smoke, I make the fire bridge of the
special construction shown at Figs. 2 and 3, that is to say, I build it up of two
parts a, b, having passages c, c¹ c², between and at each side of them for the flames
and hot products of combustion passing from the fire grate d to the flue. Each
part a, b, is made with zig-zag passages e, e', e, for the passage of air, from
the ash pit f. As the flames play upon and around the divided fire bridge it
becomes very hot and heats to a high degree the air passing through it. The air
passes from the ash pit through the zig-zag passages and finally escapes in a
highly heated condition at the back of the fire bridge where it meets and mixes
with the products of combustion from the furnace.
The fire bridge can be made with only one part such as a, for small boilers,
or again for very large boilers it may be made with more than two parts or
divisions.
On the drawings I have shown the fire bridge as having three zig-zag passage
ways but I do not confine myself to this number as I can alter the number to suit
different requirements and different classes of boilers.
The mixture of the hot air, at the back of the fire bridge, with the partially
burnt gases and fuel from the furnace greatly promotes the combustion and reduces
smoke.
The fire bridge is, preferably, built of fire brick with the passage ways divided
from each other by partitions of thin silica brick.
The fire bridge can be applied, where suitable, to any form of land or marine
boiler.
Where a gas producer is available it is very advantageous to fire the boiler
furnaces with gas in the manner shown on the drawings, that is to say, the gas is led
from the producer, which may be of any well known and suitable construction,
along a ground flue g above which is arranged a valve box h having a screw down
valve in it. This box communicates by the passages i, i, with the flues g and j.
The flue has two branches j,, leading to the side of each furnace, and entering
them at near the crown. The furnaces are, preferably, partially lined with fire
brick as shown.

page_text: Instead of using fire brick flues g, j, pipes may be employed for conducting the
gas to the furnaces.
With this arrangement for firing, a coal fire is first lit on the grate d and then
when it is sufficiently lighted, the valve i is opened and producer gas admitted to
the furnace. Air is admitted of course through the fire bridge as before stated.
The firing by gas, as above, is found to be very economical and also effective.
If desired a plate k, indicated in dotted lines at Fig. 2, can be arranged below
the fire grated to prevent air passing up through the fire grate and also to
facilitate the removal of the ash.
The gas firing arrangement can, of course, be modified to suit different styles of
boilers.
As a better combustion is produced by using the fire bridge less coal is required
to heat up the boiler.
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
consider novel and desire to claim is :-
1. A furnace fire bridge having zig-zag air passages in it, substantially as and
for the purpose hereinbefore set forth.
2. A furnace fire bridge made in two or more parts each part having zig-zag air
passages in it, substantially as hereinbefore set forth.
3. The combination with a boiler furnace having a fire bridge with passage
ways in it, of an arrangement for heating the boiler with gas substantially as
herein before described and shown on the drawings annexed'.
Dated this 3rd day of September 1896.
H. D. FITZPATRICK,
70 Wellington Street, Glasgow,, Agent,