IMPROVE- MENTS IN FURNACES FOR STEAM BOILERS
Year: 1876

page_text: LETTERS PATENT to James William Bonta, of Now Brighton, Pennsylvania,
United States of America, Chain Manufacturer, for the Invention of "IMPROVE-
MENTS IN FURNACES FOR STEAM BOILERS."
Scaled the 23rd September 1876, and dated the 3rd August 1870.
COMPLETE SPECIFICATION filed by the said James William Bonta at the Office
of the Commissioners of Patents on the 3rd August 1876.
JAMES WILLIAM BONTA, of New Brighton, Pennsylvania, United States of
America, Chain Manufacturer. "IMPROVEMENTS IN FURNACES FOR STEAM BOILERS."
My improvements, which relate to the construction of furnaces for steam boilers,
are designed to promote economy in the consumption of fuel. They accomplish this
object by affording facilities for regulating and controlling the fire, and insuring
perfect and complete combustion without cooling the furnace by the admission of
an excessive quantity of cold air, and without the use of draughts of air powerful
enough to carry off unconsumed portions of fuel in the form of sparks or smoke.
My Invention consists in the following described devices and their combinations,
to wit:-
First. A coal magazine, which is also a retort for the generation of gas from the
fuel it contains. This magazine, the external mouth of which is provided with a
tight fitting door, is situated partly within the fire chamber, and is open at the
bottom, and thus automatically feeds coal upon the grate surface as the fuel thereon
burns away.
Secondly. A pipe connecting the upper part of the coal magazine with the fire
chamber of the furnace, and provided with a valve, and connected at an acute anglo
with a pipe for injecting a blast of air, by the operation of which gas generated in
the coal magazine or magazine retort is drawn from the upper part thereof and
carried through the gas discharge pipe into the fire chamber, where it contributes
by its combustion to the heating power of the furnace.
When the valve of the gas discharge pipe is closed the coal in the magazine
retort cokes slowly, and the gas therein generated finds its way out from the
bottom of the magazine retort only, but by opening the valves and injecting air, us
has been described, through the blast pipe, the gas is drawn from the upper part
of the magazine retort, and the combustion in the lower part thereof being thereby
increased gas is generated more rapidly. I ain thus enabled to regulate the com-
bustion of fuel as may be desired, and by varying the gas generating power of the
--

page_text: magazine retort to govern the quantity of gas discharged into and burned m
fire chamber.
Thirdly. The water jacket surrounding the magazine retort within the fire
chamber, connected with the water space of the boiler, and affording a large
additional area of available heating surface.
Fourthly. In combination with a furnace provided with a combined magazine
and retort, as described, a closed ash-pit provided with an injection pipe or pipes
for supplying a jet or jets of steam or air, or both.
5
Fifthly. A supplementary combustion chamber or prolongation of the fire cham-
ber, provided with an injection pipe or pipes for injecting an additional quantity of 1
oxygen either in the form of air or steam, or both."
Sixthly. A fire-brick damper of peculiar construction, constituting the outer wall
of the supplementary combustion chamber, and serving to reflect the flaming gasos
against that portion of the boiler constituting the inner or opposite wall of the
supplementary combustion chamber.
Seventhly. An opening through the shell of the locomotive at the bottom of the
supplementary combustion chamber for the-downward exit of the heavier gases
evolved in the process of combustion.
Eighthly. An adjustable damper at the base of the smoke stack for use in
connection with the fire-brick damper in regulating the escape of the lighter
uninflammable products of combustion.
These devices may be usefully employed either separately or two or more in
combination with cach other.
The subjoined description explains their application to a locomotive, and suf-
ficiently indicates how they can be applied to a stationary boiler.
The accompanying Drawings are as follows:-
Figure 1 is a central vertical longitudinal section of a locomotive boiler and
furnace with my improvements applied thereto.
Figure 2 is a transverse vertical section through the line x, x, on Figure 1.
Figure 3 is a side clevation of the furnace and a portion of the body of the loco-
motive showing the pipe for conducting gas from the magazine retort to the fire
chamber and the injection pipe connected therewith.
Figure 4 is a transverse vertical section through the line 3, y, on Figure 1,
showing the inner side of the fire-brick damper and the injection pipes on either
side for the inlet of air or steam, or both.
Figure 5 is a front view of the fire-brick damper valve, together with the
mechanism for rotating it to open and close the damper openings.
Figure 6 is a plan of the rack and segmental pinion by which the fire-brick
damper valve is operated.
Figures 7 and 8 represent details exhibiting the construction of the perforated
fire-brick damper wall and fire-brick damper valve.
Referring to the Drawings it will be seen that they represent the ordinary
locomotive boiler A having the usual fire chamber B, the tubes C, the smoko
chamber D, ash-pit E, and grate F. The ash-pit is closed and is provided with a
door e which tightly fits an opening through which the contents of the ash-pit may
be removed. Fuel is supplied to the furnace from the coal magazine G, the external
mouth of which is closed by the tight fitting door g. It will be seen that the por-
tion of the coal magazine within the fire chamber is encased in the water jacket h, k,
which is connected with the boiler by means of the pipes and m, and is also con-
nected with the water space in the front wall of the fire chamber. These connec-
tions of the water jacket with the water body of the boiler at variable clevations
insure a constant circulation of water in the jacket when there is a fire in the furnace,
and this device affords a large additional heating surface.
The upper part of the magazine retort within the fire chamber may if desired be
perforated for the purpose of permitting the constant escape from the upper portion
of the magazine of gases generated from the coal therein contained; but in the case
of a locomotive it is preforable not to. have these openings, but instead of that to
1

page_text: discharge the gas from the upper part of the magazine retort through the pipe T,
which is provided with a valve t for the purpose of checking or wholly arresting
the exit of gas from the upper part of the magazine-retort. The gas discharge
pipe T is joined at an acute angle to an air injection pipe U, which is to be con-
nected with an air pump or blower, and provided with a valve u. When the
valves t and u are open air rushes through the injection pipe U, and gas is drawn
from the magazine-retort into the pipe T, where it is mixed with air from the
injection pipe, and the mixed air and gas is forced into the fire chamber, as shown
at W, Figures 1 and 3, or at any other desired point. For example, the pipe T¹ may
be carried forward into the supplementary combustion chamber situated in front of
the tube sheet. The point selected for the injection of the gas into the furnace is
immaterial so far as regards the main purpose of the Invention, which is to
place the generation of gas in the magazine retort under the control of the
engineer.
When gas is drawn from the magazine retort by the discharge pipe the draught
through the magazine retort from the grate surface is increased, and the coal con-
tained in the magazine retort is more rapidly coked and gas is more rapidly
generated. By means of this apparatus the engineer is enabled to suddenly increase
the heating power of the furnace by providing for the injection and combustion
therein of a rapidly increasing quantity of gas. The ash-pit E is provided with
one or more injection pipes f for the admission of blasts or jets of air or steam, or
both.
The
A short distance from the tubo sheet at the front end of the locomotive is a
vertical perforated fire-brick wall K, and the space between this wall and the tube
sheet constitutes the supplementary combustion chamber L. The perforations in
the wall K are closed or opened by the rotating perforated fire-brick disk I
latter is under the control of the engineer in the cab, being operated by means of
the rod a connected with the segmental pinion b, which engages the rack c on the
outer end of the slide bar c³, the inner end of which is pivoted to the iron frame of
the valve disk I. The segmental pinion b has its bearings on the projecting wing d,
which is affixed to the side of the boiler A. The perforations o in the firo-brick
wall K have the same relation to each other as the perforations in the valve
disk I, so that by rotating the valve disk the respective perforations may be made
to coincide in position or otherwise.
The perforated wall K and disk I, as constructed and arranged, constitute a
damper, the inner face of which reflects the flaming gases from the tubes backward
against the tube sheet of the boiler. I therefore designate the described structure
as a reflector damper. In its construction fire-clay, soap stone, porcelain, or other
similar material may be substituted for fire-brick.
The wall K consists of four segments of fire-brick or other suitable material set in
an iron frame, which is secured to the shell of the boiler. This frame consists of an
iron ring having two or more iron crossbars intersecting each other in the centre of
the ring, and affording a bearing at that point for the pivot upon which the disk I
revolves.
The disk I is composed of a similar iron frame supporting four segments of fire-
brick, each of which has substantially the shape indicated in Figures 7 and 8, by
reference to which it will be seen that the supporting frame is wholly covered by
the fire-brick, and that each segment S is provided with a laterally projecting
flange S¹, which fits around and shields the periphery of the supplementary com-
bustion chamber L, as shown in Figure 1.
The object of this reflector damper is to enable the engineer to properly adjust
and regulate the passage for the exit of the nitrogenous and incombustible contents
of the furnace, with relation to the quantity of air or steam injected into the furnace.
It will of course be understood that the various injection pipes are connected with an
ordinary blower or air pump, or with the steam space of the boiler as may be
desired.

page_text: At the base of the smoke stack there is another damper valve M for use
In connection with the reflector damper, or for independent use when the reflector
damper is allowed to remain more or less open.
In a locomotive provided with all my improvements, the exhaust pipes may be
carried to the top of the smoke stack, as the exhaust is not required for assisting
the draft. By this means there is always a free exit for the exhaust steain, and
therefore no loss of power by the existance of back pressure upon the piston;
arising from the choking of the exhaust.
It will be seen that the portion of my Invention embracing the combined coal
magazine and retort may be used in connection with a furnace having the ordinary
draft openings, or it may be used in connection with a closed ash-pit and induction
pipes for the supply of prescribed quantities of oxygen. In cither event the
operation of this part of my Invention is as follows:-
The magazine is filled with coal, and the tight fitting door g being closed to
prevent the escape of gases at that point, the fuel is ignited upon the grate bars.
As it burns away its place is supplied with fuel which falls from the magazine by its
own gravity. As the fuel within the magazine is heated inflammable vapor or gases
are generated which are either discharged into the upper part of the fire chamber
through perforations in the magazine retort, or are drawn out through the gas
discharge pipe T, where that device is adopted instead of the perforations
in the upper part of the magazine retort, or when the valves and u are
closed, make their way out slowly from the bottom of the magazine retort.
By this means the fuel prior to its discharge from the magazine retort is partially
decomposed and coked, and is delivered from the magazine retort in favorable
condition for complete combustion. If the magazine retort is cased in the water
jacket k, a large additional area of heating surface is rendered available, and by
means of the various connections of the water jacket with the water spaces a
constant circulation of the water contained in the water jacket is maintained, which
materially assists in heating the water body in the boiler. When the magazine
retort is arranged for uso in combination with the closed ash-pit and injection
pipes for the introduction of prescribed quantities of oxygen, either in the form
of air or steam, or both, the engineer injects into the ash-pit or fire chamber, or
both, more or less air or steam according to the requirements of the occasion. If
he requires less heat, instead of banking his fire he reduces the supply of oxygen,
if he requires additional heat, in addition to increasing the draft through the
magazine retort, and the quantity of gas evolved, as has been described, he increases
the supply of oxygen through the ash-pit, taking care not to exceed the quantity
of air required for combustion, and for the displacement and expulsion of the
nitrogenous or incombustible contents of the fire chamber. The induction pipe f¹
delivers a supply of oxygen in favourable position for immediate mixture with
gases discharged from perforations in the retort, but will not be required when the
gas discharge pipe T is used instead of the perforations.
It will of course be understood that in case of a fire chamber of different shape
from that shown, the position of the induction pipe f¹ will be varied according to
the position occupied by the gases generated in and discharged from the magazine
retort, the object of the induction pipe f¹ being to introduce an additional supply
of oxygen for mixture with gases discharged directly from the retort to insure their
complete combustion.
In the locomotive boiler which I have described, this principle is further
carried out by the establishment of the supplementary combustion chamber,
which is also provided with induction pipes for supplying oxygen at that point.
The opening at the bottom of the supplementary combustion chamber pro-
vides for the downward exit therefrom of the heavier uninflammable products of
combustion. .
The supplementary combustion chamber contributes a new clement to the structure
in the reflector damner which constitutes its outer wall. the reflector damper

page_text: performing the double function of reflecting the flaming gases against the tube
sheet of the boiler, and affording to the engineer a means of controlling and
adjusting the area of the outlet for the incombustible contents of the furnace. By
means of these devices the engineer is enabled to insure in the furnace a constant
supply of oxygen, accurately graduated in quantity to the requirements of the
occasion. He is enabled to feed the furnace by depositing fuel in the external
mouth of the coal magazine without being under the necessity of opening a
furnace door, and thereby permitting a large influx of cold air into the fire
chainber. By the use of the damper M in the smoke stack in connection with
the reflector damper the engineer is enabled to still more accurately regulate the
outlet for the uncombustible contents of the furnace.
What I claim as my Invention is as follows:-
First. A combined coal magazine and retort, partially contained within the fire
chamber, open at the bottom terminating a short distance above the grate surface
having perforations at its upper wall within the fire chamber, and an external mouth
outside the fire chamber provided with a tight fitting door for the purpose of
receiving, containing, and automatically delivering coal upon the grate surface,
after having subjected the coal to the heat of the furnace whereby the coal is
partially coked prior to its delivery to the fire, and the gases evolved in the process
of coking are discharged from the upper portion of the magazine retort into the
firo chamber in suitable position for contributing by their ignition to the heating of
the boiler.
Secondly. A magazine retort, substantially such as described, in combination with
a gas discharge pipe leading from the upper portion of the magazine retort to the
fire chamber, and connected with an air injection pipe, both pipes being provided
with valves for the purpose of regulating the discharge of gas from the
of the magazine retort, and thereby regulating the draft through the magazine
upper portion
retort, and governing the generation of gases from the fuel therein contained.
Thirdly. A magazine retort, substantially such as described, in combination with
a closed ash-pit and injection pipes for the introduction of prescribed quantities
of oxygen into the ash-pit, and from thence through the grate into the fire
chamber.
Fourthly. A magazine retort, substantially such as described, and a closed ash-pit
provided with an induction pipe for the introduction of oxygen below the grate bars
in combination with an induction pipe for introducing oxygen into the fire chamber
in suitable position for immediate mixture with the gasos generated and discharged
from the retort, substantially as.
Fifthly. A magazine retort, substantially such as described, surrounded within
the fire chamber by a water jacket connected at variable elevations with the water
body of the boiler by means of suitable pipes, substantially as described.
Sixthly. A fire chamber provided with a magazine retort, substantially such as
described, in combination with a supplementary combustion chamber provided with
induction pipes for supplying the said supplementary combustion chamber with
oxygen, either in the form of air or steam, or both.
Seventhly. The tube sheet of a boiler, in combination with the fire-brick reflector
damper provided with mechanism whereby the damper may be opened and closed,
substantially as described.
Eighthly. A perforated fire-brick wall, constituting the outer boundary of a
supplementary combustion chamber, substantially such as described, in combination
with a flue or smoke stack damper, substantially as described.
Ninthly. A supplementary combustion chamber, having an opening at the bottom
for the purpose of providing for the exit of the acids or heavier products of com-
bustion in a downward direction.
Tenthly. A steam boiler furnace, having a closed ash-pit provided with an
induction pipe, and a fire chamber also provided with an induction pipe; a maga-
zine retort, substantially such as described; a supplementary combustion chamber

page_text: having a pipe or pipes for the admission of oxygen therein, and an external per-
forated fire-brick wall provided with a perforated rotating fire-brick disk, the whole
constructed and operating substantially as and for the purposes set forth.
Dated this Third day of July. A.D. 1876.
Witnesses,
EDWP. PAYSON.
GEO. W. MIATT.
JAMES WILLIAM BONTA. (L.S.)