Improvements in Boiler Furnaces.
Year: 1894

page_text: '
Date of Application, 18th May, 1894
Complete Specification Left, 8th Mar., 1895-Acceptel, 13th Apr., 1895
Improvements in Boiler Furnaces.
I, OTTO FRIEDERICI, of 58 Lombard Street, in the City of London, Merchant,
do hereby declare the nature of this invention to be as follows:-
My invention relates to boiler furnaces in which closed air chambers are provided
underneath the fire gate, in which a forced air supply is induced by means of steam
jets.
In arrangements heretofore proposed for this purpose, such as were described
in the Specifications to Thompson's (Kudliez's) Patent No. 8919 of 1891 and
Klostermann's Patent No. 18136 of 1893, such air chambers were made to extend
along the whole length of the fire grate, with the result that the air pressure
produced by the steam jets was considerably greater at the inner end of the
furnace than at the front end, whereby an unequal combustion of the fuel was
effected.
According to one of my present improvements, I obviate this defect, and insure
a practically uniform air pressure throughout the fire grate, by dividing the air
chamber, or chambers beneath the grate by means of transverse partitions into two
or more separate compartments, and providing each compartment with a separate
air supply pipe and steam jet, the supply pipe for the second or inner compartment
being made to pass through the first or outer compartment and through the
partition dividing the two, while the supply pipe for the third compartment if
such be used, is carried through both the first and the second compartments.
By this means I can insure that the air pressure beneath the front part of the
fire grate shall be practically the same as that beneath the inner part of the
grate, or, by suitably regulating the steam injectors, I can maintain the exact
difference of air pressure that may be required at the inner and front parts of the
furnace.
Thus, when the furnace is to be adapted to burning very gaseous coal, I prefer
to construct the air chamber with a third smaller compartment at the inner end
next the fire bridge, and I regulate the steam jet to this so that the air pressure
therein shall be greater than in the two other compartments, in order that an
excess of air may be supplied to the fire at this point for effecting the combustion
of the combustible gases that may have passed away unconsumed from the front
part of the fire.
I prefer to superheat the steam supply to the steam jets of the air pipes, for
which purpose I provide within the front part of the furnace an arched pipe or box
extending over the fire and which is supplied with boiler steam at one end through
an external pipe passing through the frame of the door, and from the other end of
which the steam passes to the steam jets of the air supply pipes through a pipe
passing to the outside of the boiler again.
For enabling the small quantity of ashes that may accumulate in course of time
in the inner compartment of the air chamber to be removed from time to time; I
form at the bottom of the transverse partition dividing the compartments an
opening of a configuration corresponding to that of the blade of a rake used for.
removing the ashes, which opening is ordinarily kept closed by keeping the rake in
the air chamber in such, a position that its blade fits into the said opening the
handle of the rake being provided with an extension to be screwed on when cluaring
the inner compartment. If a third or fourth compartment is employed, the
partitions of these are also provided with openings through which the rake can pass

page_text: but which are provided with hinged flaps opening inwards, so as to open freely
when the rake is pushed through, and to close of themselves when the rake is
withdrawn.
°
قيم
ABEL & IMRAY,
Agents for the Applicant.
.
Improvements in Boiler Furnaces.
I, OTTO FRIEDERICI, of 58 Lombard Street, in the City of London, Merchant,
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 :-
My invention relates to boiler furnaces in which closed air chambers are provided
underneath the fire grate in which a forced air supply is induced by means of steam
jeta.
In arrangements heretofore proposed for this purpose such air chambers were
made to extend along the whole length of the fire grate with the result that the air
pressure produced by the steam jets was considerably greater at the inner end of
the furnace than at the front end, whereby an unequal combustion of the fuel was
effected.
According to one of my present improvements I obviate this defect, and ensure a
practically uniform air pressure throughout the fire grate by dividing the air
chamber or chambers beneath the grate by means of transverse partitions into two
or more separate compartments, and providing each compartment with a separate
air supply pipe and steam jet, the supply pipe for the second or inner compartment
being made to pass through the first or outer compartment and through the
partition dividing the two, while the supply pipe for the third compartment if such
be used, is carried through both the first and the second compartments.
By this means I can insure that the air pressure beneath the front part of the
fire grate shall be practically the same as that beneath the inner part of the grate,
or by suitably regulating the steam injectors, I can maintain the exact difference
of air pressure that may be required at the inner and front parts of the furnace.
Thus when the furnace is to be adapted to burning very gaseous coal, I prefer to
construct the air chamber with a third smaller compartment at the inner end next
the fire bridge, and I regulate the steam jet to this so that the air pressure therein
shall be greater than in the two other compartments, in order that an excess of air
may be supplied to the fire at this point for effecting the combustion of the
combustible gases that may have passed away unconsumed from the front part of
the fire.
The accompanying drawings show a furnace constructed according to my above
described invention."
Fig. 1 shews a longitudinal section; Fig. 2 a front view; Fig. 3 a sectional-plan;
Fig. 4 a cross section and Fig. 5 a part longitudinal section to an enlarged scale.
Fig. 6 is a section of one of the grate bars.
The invention is here shewn as applied to a Cornish boiler with two cylindrical
flues.
Into these flues are fitted separate semi-cylindrical air chambers A the upper
surface of which is formed by the grate B, which is here shewn to be of the
sectional form shewn to an enlarged scale at Fig. 6, but which may be of any other
suitable construction, and forms no part of my present invention.
The air chamber A is closed at each end by a plate C C, and is separated at or
about the middle of its length by a partition into a front and back compartment.
The front compartment is supplied with air through the nozzle D, while a separate

page_text: nozzle D¹ passes through the front compartment and partition C into the back
compartment for supplying air to the latter. A forced air supply of any desired
pressure is induced through each nozzle by means of steam jets E E' supplied from
the steam space of the boiler.
I prefer to superheat the steam before issuing from the jets, for which purpose 1
arrange an arched pipe or chamber F above the dead plate of the furnace, into one
end of which the steam is led from the boiler through the pipe G and from the
other end of which it is supplied to the steam jets through a pipe H.
As before stated, there may be provided a third compartment in the air chamber,
next the fire bridge, which would be supplied with air through a third nozzle
passing through both the other compartments and through the plate C¹.
For enabling the small quantity of ashes that may accumulate in the course of
time in the several compartments of the air chamber to be removed from time to
time, I form openings at the bottom of the plates C and C³, the opening of being
closed by a door T, while the opening of C is closed by the blade of the rake J
used for removing the ashes, as shewn at the enlarged section at Fig. 5, the rake
being ordinarily kept in the position shewn in the front air chamber, so as to close
the opening in C2, the configuration of which opening is made to coincide with that
of the rake. The handle of the rake is formed with a screw socket at its end, as
shewn, into which is screwed an extension when the rake is to be used.
If a third compartment is employed the partition of the latter is also provided
with an opening through which the rake can pass, but which is provided with a
hinged flap opening inward so as to open freely when the rake is pushed through
and to close of itself when the rake is withdrawn.
It will be evident that my above described invention can also be applied where
there are two or more separate air chambers arranged side by side beneath the
furnace grate.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what [
claim is :-
1. In boiler furnaces operating with forced draught, a closed air chamber
beneath the furnace grate divided by one or more transverse partitions into two or
more compartments in the direction of the length, each such compartment being
provided with a separate forced air supply substantially as and for the purpose
described.
2. In boiler furnaces the combination of a closed air chamber A beneath the
furnace divided by a transverse partition C into a front and a back compartment,
a nozzle D with steam jet for supplying forced air to the front compartment, and a
second nozzle D' with steam jet, passing through the front compartment for
supplying air to the back compartment, substantially as described.
3. In combination with the nozzles D D and steam jets E E' for supplying
forced air to the air chambers of a furnace, an arched steam pipe or chamber F
within the furnace, supplied with steam from the boiler and connected to the
nozzles EE for superheating the steam supply to the latter, substantially as
described.
4. In an air chamber below a furnace divided by a partition into a front and a
back compartment each of which receives a separate forced air supply, constructing
the said partition with an opening which is closed by the blade of the rake that,
is used for removing the ashes from the air chamber, substantially as described.
Dated this 8th day of March 1895
ABEL & IMRAY,
Agents for the Applicant.