Improvements in, and connected with, Hollow Fire Bars for Furnaces.
Year: 1899

page_text: Date of Application, 14th June, 1899-Accepted, 12th Aug., 1899
COMPLETE SPECIFICATION.
Improvements in, and connected with, Hollow Fire Bars for Furnaces.
I, GEORGE SANFORD LEE, of Hawthorne, New Jersey, United States of America,
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:-
This invention has relation to hollow grate bars and has for its object the
provision of means whereby air may be conveyed through the grate bar so as to
become highly heated in its passage therethrough and then mixed with the
gases and other products of combustion to produce a very high degree of heat
from a given amount of fuel and promote perfect combustion, so as to entirely
or almost entirely prevent the egress of smoke from the smoke stack.
My invention consists in the novel construction of the grate bar hereinafter
described and further consists in the novel construction, combination and arrange-
ments of parts in a furnace or fire box employing hollow grate bars hereinafter
described.
Referring to the accompanying drawing wherein Figure 1 is a vertical longitu-
dinal sectional view of a steam boiler and furnace fitted with my improvements,
Figure 2 is an enlarged vertical sectional view of one of my improved grate bars
and Figure 3 a vertical longitudinal section of a modified form of the same.
A designates the boiler, B the fire box, C the combustion chamber and D the
ash pit.
E designates one of the grate bars which are composed of two equal halves,
being divided longitudinally and vertically on a central line, each half being of
the same form as the other and the two halves being united by pins cast in one
half and passing into or through holes in the other half and rivetted on the
outside of the same, one of said pins e being shown in the sectional view Figure 2.
The two halves of the grate bar are cast with longitudinal channels which,
when the halves are united together, to form a complete bar constitute a pas-
sage for the air, composed of the upper and lower conduits F, G, which com-
municate near one end of the bar.
The conduit G opens near the inner end of the ash pit and the bridge wall H
through a neck H¹ and this conduit is enlarged at K to form a supply or accu-
mulating chamber for the already heated air. The conduit F, which com-
municates by a bend with the conduit G near the outer end of the bar, registers
with a hole k, in a channel bar that rests upon the wall H, and constitutes a
part of the fire bridge.
A sliding bar M is arranged to slide within the channel of the bar L being
supported and guided in its movements by lugs 1, at top and bottom and this
bar M is pierced with holes m, m that correspond with the holes in the channel
bar the purpose of the sliding bar being to regulate the size of the air exits
from the hollow bars of the grate, such regulation being accomplished by mov-
ing the sliding bar longitudinally by means of a prolongation extending through

page_text: the side wall of the furnace and operated from the outside by a suitable screw
or lever.
Courses of brick N, N, are built up on the ends of the grate bars and on top
of the channel iron L so as to protect them from the flames and constitute the
fire bridge proper, an arch of fire brick being thrown over the fire bridge
so as to deflect the flame downwardly in the combustion chamber and towards
the outlet of the hollow grate bars where the products of combustion meet the
highly heated air issuing from the grate bars and are thoroughly commingled
therewith. Near the forward end of the bar and on the bottom thereof, just
inside the door P of the ash pit, the grate bars E are formed with a cast bush-
ing Q, that has a port q leading into the hollow of the grate bars at the junction
of the conduits FG. The bushing Q, is closed normally by a nipple and plug
and the purpose of the bushing is to provide for the attachment of a steam pipe
from which steam may be blown through the conduits F, G, when it is desired
to blow out the dust and fine ashes that may accumulate from time to time.
Each of the double grate bars is formed with lugs S, S, on each side so as to
maintain the bars a proper distance apart, such lugs being shown in Fig. 2.
In operation the air is taken in at H', from the ash pit where it has been
already heated to a considerable degree and passing into the chamber K, is
allowed to expand and accumulate and then passes through conduit G, to or
near the forward end of the grate bars and then passes to the rear of the same
through the conduit F, and enters the combustion chamber through the holes
in the channel iron L, the amount of air so entering the combustion chamber
being regulated by the sliding bar M. The air in its passage forward and then
backward through the hollow grate bar becomes heated to a very high degree
and issues from the grate bar in such condition and mingling with the products
of combustion and gasses from the fire produces a degree of heat and perfect
combustion not hitherto accomplished by grate bars of ordinary form.
In the modified form shown in Figure 3, the conduits are of sinuous form,
the purpose being to lengthen the passage through the bar and thereby increase
the heating surface with which the air comes in contact.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what
I claim is:-
First The combination with a furnace having a bridge wall between the
fire space and combustion chamber, of a hollow grate bar, having direct and
return flues, both opening at or near the bridge wall, the return flue having
communication only with the combustion chamber, whereby all the air admitted
to the interior of the grate bar will be directed through both flues, substantially
as described.
Secondly: In a hollow grate bar, the combination with the inlet port H¹,
the chamber K, and conduit G, of the conduit F, communicating with the con-
duit G, and opening out through the rear end of the bar, substantially as
described.
Dated this 13th day of June 1899.
GEORGE SANFORD LEE,
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.