IMPROVEMENTS IN STEAM BOILER AND OTHER FURNACES AND FRONTS AND DOORS THEREFOR
Year: 1883

page_text: LETTERS PATENT to Benjamin Harlow of Macclesfield in the county of
Chester for an Invention of "IMPROVEMENTS IN STEAM BOILER AND OTHER
FURNACES AND FRONTS AND DOORS THEREFOR
PROVISIONAL SPECIFICATION left by the said Benjamin Harlow at the
Office of the Commissioners of Patents on the 19th January 1883.
BENJAMIN HARLOW of Macclesfield in the county of Chester "IMPROVEMENTS
IN STEAM BOILER AND OTHER FURNACES AND FRONTS AND DOORS THEREFOR
"
The object of this invention is to provide for the more effectual consumption of
smoke in steam boilers and other furnaces than is at present the case
At the rear end of the bars and furnace I place an air chamber and movable
bridge through which passes heated air to aid the complete combustion of smoke
and other unconsumed gases escaping from the fire. The air chamber is placed on
the brick-work or division that separates the ash box from the flue, or may be
made in one piece with the necessary division doing away with the brick work
beneath, this air chamber is preferably rectangular in shape and is provided with
stays and projections between or in which the bars rest. Over and enclosing this
air chamber, I place the movable bridge which is preferably saddle-shaped and
rests on ledges or projections round the air chamber which incline towards the
back, the bridge thus being held firmly in position by its own weight. The bridge
is encased at the back and sides so that no air can enter it but what has passed
through the fire bars which are tubular and the air chamber. At the side of the
bridge facing the flue is fixed a loose continuous grid or grating or perforation
through which the superheated air passes and coming in contact with products of
combustion as they cross over the bridge freely mingles with the heated gases and
completes the combustion of the smoke. The bridge is preferably cast in one.
piece though this is not necessary, presenting a metal surface to the flames or it
may be cast with a projecting flange on which a course of fire brick may be built,
or may be made with water way, through which a constant current of water
circulates. The front part of each bar extends below the bearers and dead plate
Prine G21

page_text: and is beveled off to allow of them being easily cleaned by means of rake or
scraper of suitable length and shape, through them also the dust or other
accumulation in the air chamber may be removed while at work and in their
normal position. These bars may run the whole length of furnace or only from
the back section.
Embedded in the top of fire bar and cast flush with it, I insert a piece of
wrought iron running the whole length, which considerably strengthens it and
provides a hard wearing surface on the face which comes in contact with the
burning fuel.
To allow of the admission of a current of heated air over the fire necessary for
complete combustion I make the furnace front or doors of three or more plates
admitting the air through a series of holes in the front or outside one, the air then
passes through a single hole in the centre of centre plate or partition of door and
then again through a series of small holes in the inner plate, and thence to the
furnace, the quantity of air admitted is regulated by a valvo placed on the hole in
the centre plate which can be opened or shut by a handle on the outside of door.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Benjamin Harlow in the Great Seal Patent Office on the 19th July
1883.
BENJAMIN HARLOW of Macclesfield in the County of Chester
"IMPROVEMENTS
"
IN STEAM BOILER AND OTHER FURNACES, AND FRONTS AND DOORS THEREFOR
The object of this invention is to provide for the more effectual consumption of
smoke in steam boilers and other furnaces than is at present the case.
The invention is best described by aid of the accompanying drawings, in which
Fig. 1 is a perspective sectional view of furnace.
Fig. 2 a similar view of door, and Fig. 3 section of bar shewing position of
wrought iron piece J.
At the rear end of the bars A and furnace I place an air chamber B and movable
bridge C, through which passes heated air to aid the complete combustion of smoke
and other unconsumed gases escaping from the fire. The air chamber is placed on
the brick work or division that separates the ash box D from the flue E, or may
be made in one piece with the necessary division, doing away with the brick work
beneath; this air chamber is preferably rectangular in shape, and its bottom, upon
which the ends of the bars rest, is preferably formed in one piece with it, and is
supported in any convenient manner. Over and enclosing this air chamber I place
the movable bridge C, which is preferably saddle-shaped, and rests on ledges or
projections round the air chamber which incline towards the back, the bridge thus
being held firmly in position by its own weight. The bridge is encased at the
back and sides so that no air can enter it but what has passed through the fire
bars A (which are tubular) and the air chamber. The side of the bridge facing the
flue is formed of a loose continuous grid or grating H, with series of perforations,
through which the superheated air passes, and comes in contact with products of
combustion as they cross over the bridge, freely commingling with the heated
gases and completing the combustion of the smoke. The bridge is preferably
moulded in one piece, though this is not necessary, presenting a metal surface to
the flames, or it may be cast with a projecting Hange on which a course of fire
brick may be built, or may be made with water way, through which a constant
current of water circulates. The front part of each bar extends below the bearers
and dead plate, and is beveled off at I, to allow of them being easily cleaned by
means of a rake or scraper of suitable length and shape, through them also the
dust or other accumulation in the air chamber may be removed while at work and
in their normal position. These bars may run the whole length of furnace or only
from the back section.
Embedded in the top of fire bar and cast flush with it, I insert a piece J of
wrought iron running the whole length, which considerably strengthens it and
provides a hard wearing surface on the face which comes in contact with the
burning fuol.
To allow of the admission of a current of heated air over the fire necessary for
complete combustion, I make the furnace front or doors as illustrated in Fig. 2, of
hree or more plates, admitting the air through a series of holes K K in the front
or outside one, the air then passes through a single hole L in the centre of contro
late or partition of door, and then again through a series of small holes M M in
he inner plate, and theuce to the furnace; the quantity of air admitted is regu-
ated by a valve N placed on the hole Lin the centre plate, which can be opened or
hut by pulling or pushing a handle on the outsi-le of door-or if the bandlo shank
e screwed then simply by turning it.

page_text: Having now described my.invention and the best modo known to me of carrying
it into effect I wish it to be understood that I do not bind myself to the exact
arrangements shown, but that what I claim as new and to be protected under tho
herein before in part recited Letters Patent is :—
1st. The manufacture of steam boiler or other furnaces with hollow fire-bars leading
to a hollow bridge or air chamber, which connects with the flue behind the
bridge, or the part above the bridge, by means of a series of perforations in the
bridge itself, substantially as described.
2nd. The wrought iron piece J. running the length of the fire bar, and cast with it,
substantially as and for the purposes described.
3rd. The method of and apparatus for warming and admitting air into the furnace
in which the gases circulate between and through the different parallel
partitions of the door, and are controlled by a valve or valves, substantially
as described.
In witness whereof I the said. Benjamin Harlow have hereunto set my hand
and seal this Seventeenth day of July in the year of our Lord one thousand
eight hundred and eighty three.