Improvements in Furnaces and Furnace Bars.
Year: 1894

page_text: Date of Application, 6th Sept., 1894-Accepted, 3rd Nov., 1894
COMPLETE SPECIFICATION.
Improvements in Furnaces and Furnace Bars.
We DENNIS MELLOR and MILTON MELLOR both of Highbury Vale, Bulwell,
Nottingham, Engineers, 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 construct furnace bars and to so arrange them
in the furnaces that they will supply sufficient air not only for primary combustion
but also a quantity of hot air for secondary combustion, the result being the bars
are kept cooler, they will last much longer, fuel is economised and the production of
smoke is considerably reduced.
In the accompanying drawings
Figure 1 is a longitudinal section of a furnace constructed in accordance with
this invention ;
Figure 2 is a section on the line x x of Figure 1;
Figure 3 is a plan of the front ends of six bars shewing the transverse steam
pipe A;
Figure 4 is an enlarged perspective view of the front of a fire bar and Figure
is a cross section of said bar.
Figure 6 is a modification of Figure 1 and Figure 7 is an enlarged cross section
of the bar shewn in Figure 6.
The same letters of reference where they occur are used to denote the same or
corresponding parts in the several figures.
For the purpose of consuming inferior fuel and for creating a forced or assisted
draught we use steam jets or bring into requisition a fan or its equivalent for
forcing into and underneath the furnace and up between the bars sufficient air for
the purpose desired.
.
For regulating the amount of air either through or underneath and up between
the bars we employ a hinged lip or air guide plate E. We construct the fire bars C
channel shaped as shewn in Figure 7 or hollow in transverse section as shewn in
Figure 5. They may be made of cast iron, steel, or other material and to make
them more refractory they may be chilled on the top edge. They may be made
in parts and afterwards be fastened together to form a complete bar. They may
be constructed corrugated, serrated, grooved or have projections with vertical
perforations of any desired shape, or they may be made plain.
They may be perforated from the top or sides to the internal air passage with
holes of any shape. The front part C¹ of each bar is made both wider and deeper
than any other portion and the head thus forined is of the same width for its full
depth so that when placed in position the front and sides of the air inlet are vertical
or nearly so and when placed in situ form an obstruction to the draught passing
under the furnace. This construction also provides an enlarged opening to the
internal air passage of the bar so as to admit the largest possible amount of air and
being so constructed they are adaptable for the attachment of the air guide or
regulator plate E. The front part C of the bar is so made that little or no
alteration need be made to the ordinary dead plate. A strip D₁ is cast on the new
dead plate or a wrought iron strip is afterwards fastened to the dead plate bearer D,
so that when the small recess C³ C made crosswise in the shoulder C² of the
bar is placed upon the strip D' on the dead plate bearer D it holds the bars firmly
in position.

page_text: When the bars are made in more than one length the middle joints are socketted
into and kept in position by the lugs W which are made under the bars fitting
between the sides of a suitably constructed bearer X see Figures 1 and 6.
In one design the back end of back bars are carried through the bridge B (as
shewn in Figure 1). It will be understood that air entering the enlarged orifice
beneath the dead plate and passing through the hot bars will be in a heated
condition when discharged at the rear of the furnace thus supplying air in a heated
condition at the rear of the bridge and diminishing the production of smoke. To
the front enlarged orifices C' of the bars may be attached a guide and regulator
plate E which may he perforated with holes of any desired shape to divide the air
into currents. Any suitable regulator such as the damper E2 may be employed to
close or determine the sizes of these perforations. The plate is preferably hinged
at E' and secured by the slots C³ (see Figures 2 and 4) to the lips of the bars and
adjusted and regulated by any suitable means.
In another form of these bars and for the purpose of producing them cheaper
and to give similar results they are left open at the bottom edge thus forming an
air channel or saddle shape (as shewn in Figure 7). The back end of these open
edged bars may be carried to, into or through the bridge B, but to give the best
results, the bars are preferably made a little shorter than the furnace so that air
passing along under the arch of the bars may have free ingress into the furnace
between the end of the bars and the bridge as shewn in Figure 6. The back end
of these saddle shaped bars are preferably carried the full depth so that the
bearer G will form no impediment to the currents of air in their passage to the
furnace. To regulate the amount of air admitted at the bridge and to also allow
for the escape of the ash, we use the shut off device shewn in Figure 6 which
consists of a hinged or pivoted trap door F preferably carried by the rear bearer G
and furnished with a counterweight H so arranged as to keep the trap door closed
against the bridge as shewn. Suitable means may be provided for actuating the
trap door, or the counterweight may be so made that the trap door will auto-
matically open when a quantity of ash bas accumulated on the upper side thereof
and same will be discharged into the ashpit, the trap door returning again to its
closed position by the action of the counterweight. In connection with the bars
for the purpose of further assisting the draught or when it is desired to burn an
inferior class of fuel we connect a steam pipe, or pipes placed parallel, and under-
neath the bars with nozzles or perforations directing jets of steam up and between
the bars to force more air into the furnace for primary combustion. Practically
and economically we prefer to fix the steam pipe A, which is fed by the branch A',
crosswise, and fitted just behind the lip of the bars (as shewn in Figure 1) with
nozzles or perforations a directing jets of steam for the forcing of air between the
bars as shewn in Figure 3. Any number of jets may be used and directed in any
way to most effectually force the largest quantity of air into the furnace.
In fixing the steam blower to the saddle shaped bars it is found desirable to
adjust the steam jets so that they will better propel the currents of air along
beneath the arch of the bars and we therefore prefer to fit them in the position
shewn in Figure 6.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A hollow fire bar having an enlarged box front and side notches to engage
with a ridge on the dead plate bearer substantially as described and shewn in
Figures 1 and 4 and for the purpose stated.
2. A saddle shaped fire bar having side notches to engage with a ridge on the
dead plate bearer and made of the same depth at the rear as at the middle
substantially as and for the purpose herein before described and illustrated in
Figures 6 & 7.
3. For regulating the admission of air to the ash pit of a furnace grate, an air

page_text: regulator or damper plate hinged to the underside of the firebars or pivotted at
or to the sides of the furnace substantially as described and shewn in Figures 1, 2
and 6 of the accompanying drawings.
4. In combination with a furnace fire grate having hollow or saddle shaped bars
discharging heated air in front of the bridge, a counterweighted and pivoted or
hinged trap door for shutting off communication between the ashpit and the space
between the ends of the bars and the bridge substantially as described and shewn
in Figure 6.
5. A furnace fire grate constructed and arranged substantially in the manner and
for the purpose hereinbefore described and illustrated.
Dated this 6th day of September 1894.
F. W. GOLBY,
36, Chancery Lane, London, W.C., Patent Agent for the Applicants.