IMPROVEMENTS IN STEAM-BOILER FIRE-BOXES
Year: 1882

page_text: LETTERS PATENT to William Robert Lake, of the firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an invention
of "IMPROVEMENTS IN STEAM-BOILER FIRE-BOXES."-A communication .from
abroad by Robert Loudon Walker, of Boston, Massachusetts, United States
of America, Engineer.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 11th July 1882.
WILLIAM ROBERT LAKE of the firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London "IMPROVEMENTS IN STEAM-BOILER FIRE-BOXES."
A communication from abroad by Robert Loudon Walker, of Boston, Massachusetts,
United States of America, Engineer.
My invention relates to improvements in steam-boiler fire-boxes which are
divided into compartments and in which the products of combustion from one
compartment are made to pass through another compartment on their way to the
chimney.
My objects are to prevent smoke by causing the gases from fresh fuel to come in
contact with highly heated surfaces; to ensure proper water circulation in the
water leg that divides the fire-box longitudinally; to prevent the damper and its
supports from being injured by the intense heat to which they are exposed; to
connect the damper, which covers the outlets from the compartments, by means
of a self packing water-tight joint, to the water leg that divides the tire box; and
to cause all flakes, cinders and the like, that are carried by the draught; especially
in locomotive-boilers, from the fuel in one compartiment to be arrested and
consumed in the other compartment.
The accompanying drawing illustrates the fire box of a locomotive embodying
these improvements.
Figure 1 is a longitudinal section and
Figure 2 is a transverse section on the line x,-x, Figure 1, of a fire box divided
longitudinally by a water-leg into two compartments which are partly covered by
arched fire brick,
Figure 3 is a sectional view of the damper, showing its connection to the
water-leg.
Figure 4 is an elevation, and
Figure 5 a cross section of one of the fire-bricks that form part of the covers to
the compartments.
Figures 3, 4 and 5 are drawn to an enlarged scale.

page_text: The fire-box A is divided longitudinally by the water leg B. Arched fire
bricks C, C., supported by the water leg B and the sides of the fire box, cover the
divisions to within a certain distance from their ends, and make two compartments
or separate fire-boxes D, D'., each having an outlet into a combustion-chamber E,
at the end not covered by fire-brick, and cach communicating with the other
through one or more openings b, in the water leg B. Heretofore, in fire-boxes of
this class the roof or cover of the compartments has been made of metal plates
protected froin the heat by being covered with wator, in which case, as is well
known, the plates cannot be heated above the temperature of the water, a degree
of heat altogether insufficient to cause the combustion of the gases from the fresh
fuel, but in this improved tire-box, the roof, or cover, of the compartments, is made
of fire-brick, or may have a water-leg to form the bottom of the combustion-
chamber or upper compartment E, and a fire-brick lining underneath this water-
leg, the essential feature being some refractory material directly over the fuel,
with which material the gases from the fresh fuel in one compartment must come
in contact on their passage through the other compartment. This material becomes
intensely heated, and raises the temperature of the gases to the requisite point to
cause them to combine with the oxygen drawn in through the incandescent fuel
in the compartment through which the gases are made to pass and thereby ensures
the perfect combustion of these gases, and effectually prevents smoke.
This combination of fire-brick or other suitable refractory substanco (placed
directly over the fuel and forming the cover of the compartments) with the water-
leg that divides the furnace longitudinally, and with a damper for alternately
closing the outlets of the compartments and causing the gases from the fresh fuel
in one compartment to pass over the incandescent fuel and come in contact with
the highly heated roof of the other compartment, so that the temperature of the
gases is raised to the degree requisite for their perfect combustion instead of
being kept below that degree of heat by contact with a metal water-leg cover,
distinguishes my fire-box from those heretofore constructed on this principle; and
makes it in fact a sure preventor of smoke, and constitutes an important feature of
my invention.
The water-leg B is braced by the inclined pipes & d. extending therefrom to
each side of the boiler. These pipes or braces d d. also form the means for water
communication and circulation between the water-leg and the boiler and serve as
supports for the damper F.
Each of the compartments D, D'. is provided with a door for the introduction
of fuel. The outlets of both compartiments are covered alternately by the damper F.
provided with interior water ways and capable of being rocked by a shaft f. One
end f¹, of the shaft must have a water tight connection with the water leg B;
and the other end f³, which projects through the water space of the fire box and
receives a handle for operating the damper, must also have a water-tight connection
with the interior of the boiler to provide a circulation through the boiler to protect
it from the heat of the furnace.
The connection at the end f¹. is inside the fire-box and covered by the fire-brick
roof of the compartments, and consequently inaccessible, and this invention provides
facilities for keeping this connection water-tight. To accomplish this result I
attach to the water-leg B a pipe or hollow block b. which communicates with the
interior of the water-leg and has an accurately bored concavity 63. to receive the
convex end of the shaft of the damper F. The other end f³ of this shaft which
passes through the water space of the fire-box is provided with a collar f³, against
which a suitable spring ft. abuts. The spring f. encircles the shaft and is secured
between the collar fa. and a plate f³. which fits the shaft and is secured by nuts on
the bolts f. f. fastened to the boiler plate. By means of these nuts any desired
pressure can be brought upon the spring f to keep the convex end of the
shaft pressed water-tight against the concavity 62. and cause sufficient friction
to hold the damper in any position, thereby obviating the necessity for any

page_text: counterbalancing device. It is obvious that the concave and convex parts may be
reversed without affecting the result.
A pipe H, communicating with the interior of the boiler is connected to the outer
end of the shaft, by a stuffing box joint, and completes the circulation. Proper
valves, not shown are provided to close the pipes b'. and H in case of accident.
To prevent sparks and waste of fuel, I make the underside of the fire-bricks C, C'.
with deep corrugations c, c. These corrugations lie across the path of the products
of combustion on their way to the outlets and so impede and deflect any solid
particles that they fall back on to the incandescent fuel of the compartiment through
which they would otherwise be drawn by a powerful draught, and are completely
consumed. By thus corrugating the underside of the fire-bricks, which constitute
practically a horizontal partition between the grate and crown plate, I provide a
simple and very effective spark-arrester.
When one compartment is replenished with fuel, it is closed by the damper and
the smoke is caused to pass out through and over the incandescent fuel and in
contact with the highly heated roof of the other compartment, and is fully
consumed. The corrugations being so close to the top of the fuel over which
any solid particles from the fresh fuel must pass, effectually arrest their progress
and cause them to fall back and be consumed, thereby preventing sparks and
saving fuel.
Having thus fully described the said invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I Claim―
First. In combination with the two compartments or fire-boxes D, D¹., the com-
bustion chamber E, and the fire-bricks C, C¹, arranged substantially as set forth
for the purpose specified.
Second. In combination with the fire box divided longitudinally by the water-
leg B., the damper F, constructed substantially as described and supported on the
inclined pipes d, d'. arranged as shown and adapted to brace and ensure circulation
in the water-leg B substantially as set forth.
Third. The combination with a water-leg for dividing a fire-box longitudinally
as described, of the pipe or hollow block which constitutes a medium for connecting
the interior of the water-leg with the hollow shaft of a damper provided with interior
water-ways substantially as, and for the purposes: set forth.
Fourth. The damper having interior water ways, and a shaft with hollow ends
which communicates with these water ways, and is provided at one end with
means for a water-tight connection to the pipe or block on the water-leg, and at
the other end with means for receiving the thrust of a spring and for a water-tight
connection to the interior of the boiler, substantially as, and for the purposes, set
forth.
Fifth. In a fire-box divided into two parts by a longitudinal water-leg and
baving both parts covered with fire-brick as described, a series of corrugations on
the under side of the cover and across the path of the products of combustion,
substantially as, and for the purposes, set forth.
In witness whereof I the said William Robert Lake have hereunto set my
hand and seal this Eleventh day of July in the year of Our Lord One
thousand eight hundred and eighty two