IMPROVEMENTS IN FIRE-BOXES OF STEAM-BOILERS OR OTHER FURNACES FOR THE PURPOSE OF CONSUMING SMOKE
Year: 1881

page_text: LETTERS PATENT to James Shepherd, of the City of Manchester, Engineer,
for an Invention of "IMPROVEMENTS IN FIRE-BOXES OF STEAM-BOILERS OR
OTHER FURNACES FOR THE PURPOSE OF CONSUMING SMOKE."
PROVISIONAL SPECIFICATION left by the said James Shepherd at the
Office of the Commissioners of Patents on the 6th October 1881.
JAMES SHEPHERD, of the City of Manchester, Engineer. "IMPROVEMENTS
IN FIRE-BOXES OF STEAM-BOILERS OR OTHER FURNACES FOR THE PURPOSE OF
CONSUMING SMOKE."
The object of this Invention is to consume the gases evolved from burning coal
in steam boiler and other furnaces, and so prevent the passage of unburnt black
and sooty matter into the atmosphere.
To attain this and to effect my improvements I employ air boxes or heaters of
cast iron or other suitable material, which may be used in lieu of or in combination
with the ordinary fire bridge, and may be of the same form and dimensions as
the ordinary bridge. The air boxes or heaters are constructed hollow and in
compartments communicating one with another by openings in the division plates.
The lower interior portion of the air box or heater on the front side has communi-
cation with the atmosphere, and the upper portion with the furnace or products
of combustion above the fire bars. Air may be blown into the air box or heater
by a fan or blower, or conducted thereto by a pipe fitted with an open cowl;
but for general purposes, the volume of air passing under the ash pit will be
sufficient. By this arrangement the air used for combustion is made hot by
passing it through such air boxes or heaters aforesaid in subdivided streams, and
as the heat is most intense at this part of the furnace, when the air box or heater
is fixed, the air as it leaves the air boxes or heaters is in a highly rarefied condition,
mixing freely with the gases from the fuel, thereby increasing their temperature
and ensuring active combustion. In addition to this I use hot air in front of the

page_text: fire above the bars. For this purpose the furnace door is made with an inner and
an outer casing, the inner casing is fixed at an angle suitable to the height of fuel
usually kept on the grate. To the outer casing of the door I connect the air box
or heater by means of a pipe which conveys the hot-air to the furnace front, and
which same pipe also forms the hinge upon which the door opens and shuts.
The end of this pipe is fitted with a valve or tap regulated by a lever passing
through the front plate of the door, and is easily worked by the attendant.
I am aware that hot-air has been used for promoting combustion, and I am also
aware that compressed air has been used for the same purpose, but these are
different from this my present Invention, which mainly consists in the employment
of air boxes or heaters used in lieu of the ordinary fire bridge, or in conjunction or
connection therewith, for the purpose of heating the air required in the combustion
of fuel and in the method of distribution already described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Shepherd in the Great Seal Patent Office on the 6th
April 1882.
JAMES SHEPHERD, of the City of Manchester, Engineer. "IMPROVEMENTS IN
FIRE-BOXES OF STEAM-BOILERS OR OTHER FURNACES FOR THE PURPOSE OF
CONSUMING SMOKE."
The object of this Invention is to obtain a more perfect combustion of the
burning fuel in steam boiler and other furnaces, and so prevent the passage of
unburnt black and sooty matter into the atmosphere.
To attain this and to effect my improvements I employ air boxos or heaters of
cast iron or other suitable material, which may be used in lieu of or in combination
with the ordinary fire-bridge, and may be of the same form and dimensions as the
ordinary bridge.
These air-boxes or heaters are constructed hollow, in box-form, with sides, ends,
top, & bottom, and divided into compartments communicating one with another
by openings in the division or deflector plates.
These plates may be fixed parallel to each other in tiers, or may be fixed at an
angle so as to allow free communication from one compartment to another. Tho
lower interior portion of the air box or heater on the front side has communication
with the atmosphere, and the upper portion with the products of combustion
above the fire bars. In operation the atmosphere travels along the ash pit and
enters the heater at the low level, and thence passing upwards through the
different compartments in a zig-zag direction to the exit opening at the back of
the heater.
By this arrangement the air used for combustion is made.hot by passing it
through such air-boxes or heaters aforesaid in sub-divided streams; and as the heat
is most intense at this part of the furnace when the air-box or heater is fixed, the
air as it leaves the air-boxes or heaters is in a highly rarefied condition, mixing
freely with the gasses from the fuel, thereby increasing their temperature and
ensuring active combustion. In addition to this I sometimes use hot air in front
of the fire above the bars. For this purpose the furnace door is made with an
inner and an outer casing, the inner casing is fixed at an angle suitable to the
height of fuel usually kept on the grate. To the outer casing of the door I connect
the air-box or heater by means of a pipe which conveys the hot air to the furnace
front, and which same pipe also forms the hinge upon which the door opens and
shuts. The end of this pipe is fitted with a valve or tap regulated by a lever,
passing through the front plate of the door, and is easily worked by the
attendant.
For the purpose of regulating the escape of air from the heater into the boiler
Blue, an adjusting bar is bolted to the back of the heater, whereby the area or
opening of the angular slot may be regulated according to the working requirements.
The front of the heater is shielded by a lining of firebricks, carried by a bearer
attached to the heater, and which may also be used when required as a back bar
bearer. In ordinary work the heater depends entirely for its operation upon the
draught in the chimney. It is naturally automatic. The greater the furnace heat
and the larger the quantity of air passing through the heater, the lower the
temperature and the smaller the quantity in a given time.
But that the improvements may be better understood I will by the aid of
the accompanying Drawings proceed more fully to describe means employed
by me,

page_text: DESCRIPTION OF DRAWINGS.
Fig. 1 shows a longitudinal section, Fig. 2 shows a transverse section at A, B,
and Fig. 3 shows a transverse section at C, D, of portions of apparatus arranged
according to my Invention.
The saine letters indicate corresponding parts wherever they occur, a, a, are
the compartments formed in the air-box or heater by means of the division
plates a, a. These plates may be arranged entirely horizontal, or at an angle,
or in combination, as shown, as may be required, according to the nature of the
work. b, b, is the adjusting bar for regulating the supply of air; c, c, is the shield
of fire-brick carried by or on the bearer d, d, attached to the heater, and on
which the fire-bars may rest when required.
Having now described my improvements and means I adopt in carrying the
same into effect, I would have it understood that I do not confine inyself to the
precise details shown and described, as variations may be made without departing
from the peculiar character of the Invention.
But what I do claim is,—
First. The apparatus for receiving and heating atmospheric air for the purpose
of promoting a more perfect combustion of the gasses evolved from burning
fuel in the furnaces of steam boilers and other furnaces, substantially as shown
and described.
Second. The use of hollow box bridges or heaters constructed with deflector
plates, whereby a current of air is heated during its passage in a zig-zag direction
from the lower to the higher level, substantially as described.
Third. The use of adjusting bars for the purpose of regulating the area of the
exit opening in heaters or bridges of this description, substantially as shown and
described.
In witness whereof, I, the said James Shepherd, have hereunto-set my hand
and seal, this Fourth day of April, One, thousand eight hundred and
eighty two.
Witness,
GEORGE FREDERICK GADD,
Assistant Consulting Engineer,
64, Barton Arcade,
Manchester.
JAMES SHEPHERD. (L.S.)