IMPROVEMENTS IN THE FURNACES OF STEAM GENERATORS, APPLICABLE ALSO TO OTHER PURPOSES."
Year: 1880

page_text: LETTERS PATENT to Jacob Salter, of Manchester, in the County of Lancaster,
Engineer, for an Invention of "IMPROVEMENTS IN THE FURNACES OF STEAM
GENERATORS, APPLICABLE ALSO TO OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said Jacob Salter at the Office of
the Commissioners of Patents on the 2nd October 1880.
JACOB SALTER, of Manchester, in the County of Lancaster, Engineer. "IMPROVE-
MENTS IN THE FURNACES OF STEAM GENERATORS, APPLICABLE ALSO TO OTHER
PURPOSES."
My said Invention, which relates to the furnaces of steam generators, consists
principally of a novel arrangement of the bars of such furnaces whereby the
consumption of smoke is effected and also an economy in fuel. As at present
arranged the fire bars usually extend from the dead-plate along the flue to the
bridge in a horizontal or nearly horizontal plane. In course of firing the fuel at
the back of the furnace usually becomes fused into a mass of "clinker," so that
the air admitted beneath the bars penetrates the mass with difficulty, and the
combustion is therefore sluggish at that point, whereby a large portion of the smoke
and inflammable gases evolved at the front and middle of the furnace passes over
the bridge without becoming ignited. In order to obviate this disadvantage I
arrange the front and back portion of the furnace at an angle to each other, that is to
say, I cause the front set of firebars to slope from the dead plate downwards, and
the back set from the bridge downwards, the two sets meeting at an angle at a
point distant from the door, say, two-thirds of the entire length of the furnace.
In order to effect this more conveniently I prefer to raise both the bridge and dead-
plate somewhat higher than their ordinary positions. The angular space between
the two sets of bars so situated forms a pit which receives the main body of the
fuel, the thickness of fuel growing less towards the front and back of the furnace,
with the result that the comparatively thin layer of fuel at the back is easily
percolated by the hot air passing beneath the furnace bars, and is thereby
kept in such a state of incandesence as to ignite and consume the inflammable
gases and smoke passing over the bridge. A more uniform temperature throughout
the length of the furnace is thus obtained, its useful effect is considerably increased,
while a corresponding economy in fuel is effected. Instead of forming the firebars
with a separating strip the whole depth of the bar, as at present, I prefer to use a
small diamond shaped patch for the purpose, and thus the air is allowed freer
access to the fuel. The hereinbefore described angular arrangement of the fire
bars may be applied to furnaces other than those of steam generators.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Jacob Salter in the Great Seal Patent Office on the 29th March
1881.
JACOB SALTER, of Manchester, in the County of Lancaster, Engineer. "IMPROVE-
MENTS IN THE FURNACES OF STEAM GENERATORS, APPLICABLE ALSO TO OTHER
PURPOSES."
My Invention, which relates to the furnaces of steam generators, consists
principally of a novel arrangement of the bars of such furnaces whereby the
consumption of smoke is effected and also an economy in fuel is promoted. As at
present arranged the fire bars usually extend from the dead plate along the flue to
the bridge in a horizontal or nearly horizontal plane. In course of firing the fuel
at the back of the furnace usually becomes fused into a mass of "clinkers," so
that the air admitted beneath the bars penetrates the mass with difficulty, and the
combustion is therefore sluggish at that point, whereby a large portion of the
smoke and inflammable gases evolved at the front and middle of the furnace
passes over the bridge without becoming ignited. In order to obviate this
disadvantage I arrange the front and back portions of the furnace at an angle to
each other, that is to say, I cause the front set of fire-bars to slope from the
dead-plate downwards and the back set from the bridge downwards, the two sets
meeting at an angle at a point somewhat nearer to the bridge than to the door.
The herein before described angular arrangement of the fire-bars may be applied to
furnaces other than those of steam generators.
And in order that my Invention may be fully understood I have attached
hereunto a Sheet of Drawings, made to a scale of about 3 inches to the foot, and
marked with letters of reference, to which Drawings I will now refer in this place.
Fig. 1 represents a vertical longitudinal section, and Fig. 2 a vertical cross section
at the line A, B, Fig. 1, of the furnace flue of a steam generator fitted in accordance
with my Invention. In the said Figs., a is the ordinary dead-plate, b the bridge,
c the front grate, and d the back grate. It will be seen that the front grate
slopes downwards from the dead plate towards the bridge, and that the back
grate slopes downwards from the bridge towards the rear end of the front grate.
In the example the front grate is about twice the length of the back grate, and
the slope of the latter is greater than the slope of the former, these being the
proportions which I consider to be suitable, but I do not confine myself to such
proportions. In the example the front grate consists of two sets of bars, but I do
not confine myself to this. To keep the bars at the distances apart necessary to
form the air spaces I cast diamond shaped studs or projections e, e, upon the bars.
I consider this construction to be much better than the separating ribs or strips
which are usually cast upon fire bars, and which extend the whole depth of the
bar, as the projections e permit the air to have freer access to the fire. Any
suitable form of bar may be substituted for the bars represented in the Drawings.
In order to obtain the required slopes in the grates it is necessary in some cases to
make the bridge and the dead plate a little higher than usual.
It will be seen
that by reason of the inclination of the grates the thickness of the fuel is or may
be greatest at about the junction of the two grates, and becomes less towards their
upper ends, that is to say, towards the front and back of the furnace, the result
being that the comparatively thin layer of fuel at the back of the furnace is easily
percolated by the hot air flowing beneath the grates, and is thus kept in such a
state of incandescence as that the gases become entirely consumed and the
formation of thick smoke is thereby prevented. A more uniform temperature
throughout the furnace is obtained, the useful effect is greatly increased, and at
the same time these advantages are attended with economy in the consumption of
fuel.

page_text: Having now fully set forth and indicated the nature of my said Invention, and
the manner in which I prefer to carry the same into practical effect, I would have
it to be understood that I claim,―
First. The furnace, constructed and arranged substantially as set forth and
indicated herein before and in and by the accompanying Drawings.
Secondly. The two grates sloping in opposite directions, substantially as and for
the purpose set forth and indicated.
rds the bridge and the shorter back
grate sloping with a greater inclination towards the said front grate, substantially
as and for the purpose set forth and indicated.
Thirdly. The longer front
And, lastly. The studs or projections e for the purpose set forth and indicated.
In witness whereof, I, the said Jacob Salter, have hereunto set my hand and
seal, this Twenty-fifth day of March, in the year of our Lord One thousand
eight hundred and eighty-one.
Signed, sealed, and delivered
in the presence of
EDWARD K. DUTTON,
41, John Dalton St.,
Manchester,
(Agent for the Patentee).
JACOB SALTER. (L.S.)