IMPROVEMENTS In on ApplicaBLE TO STEAM GENERATOR on other FURNACES
Year: 1881

page_text: LETTERS PATENT to Luke Shaw and Peter Thomas Fletcher, both of
Manchester, in the County of Lancaster, for an Invention of "IMPROVEMENTS
In on ApplicaBLE TO STEAM GENERATOR on other FURNACES."
PROVISIONAL SPECIFICATION left by the said Luke Shaw and Peter
Thomas Fletcher at the Office of the Commissioners of Patents on the 22nd
September 1881.
LUKE SHAW and PETER THOMAS FLETCHER, both of Manchester, in the County
of Lancaster. "IMPROVEMENTS IN OR APPLICABLE TO STEAM GENERATOR OR
OTHER FURNACES."
Our Invention relates principally to the furnaces of stoam generators, and has
for its object to promote the combustion of the fuel so as to a great extent to avoid
the emission of smoke. To this end we construct a bed of tiles, fire-brick, or
other suitable material between the back ond of the grate and the bridge, which
lattor is placed further back than is usual, and we form an air inlet passago
between the end of the grate and the said bed. In one construction the said
passage is formed in a wall, which extends to the levol of the grate, or a little
below the said level, and opens to the front. The front opening is fitted with a
Blanting dampor, which is connected with a suitable apparatus which will permit
the said damper to close slowly after the furnace doors have been shut after the
ordinary firing. The outlet of the passage is provided with a grating or perforated
mouth piece of iron, fire-clay, or other suitable material, and by preference a short
slanting bed extends from the said outlet to the end of the grate. An air inlet
grating or opening is formed below the damper opening, and air is permitted to
pass through the said air inlet grating and to flow below the bed, which is in front
of the bridge, the air passing off through an opening which leads into the first
named air-inlet passage, the intention being to prevent over-heating of the said
bed and to provide a constant current of beated air. The said bed is kept covered
with a layer of incandescent fuel, which may he supplied at intervals from the
fire grate. The products of combustion flowing from the furnace meet the upward
issuing current of heated air and mingle therewith as they pass over the bed of
incandescent fuel, whereby the said products become consumed before passing into
the cooler rear flue, thereby in our opinion preventing the formation of black
smoke.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Luke Shaw and Peter Thomas Fletcher in the Great Seal Patent
Office on the 22nd March 1882.
LUKE SHAW and PETER THOMAS FLETCHER, both of Manchester, in the County
of Lancaster. IMPROVEMENTS IN OR APPLICABLE TO STEAM GENERATOR OR
26
OTHER FURNACES."
Our Invention relates principally to the furnaces of steam generators, and has
for its object to promote the combustion of the fuel so as to a great extent to
avoid the emission of smoke. To this end we construct a bed of tiles, fire-brick, or
other suitable material between the back end of the grate and the bridge, which
latter is placed further back than is usual, and we form an air inlet passage
between the end of the grate and the said bed. The air inlet opening is fitted
with a slanting damper, which is connected with a suitable apparatus which will
permit the said damper to close slowly after the furnace doors have been shut after
the ordinary firing. An air inlet grating or opening is formed below the damper
opening, and air is permitted to pass through the said inlet grating and to flow
below the bed, which is in front of the bridge, the air passing off through an
opening which leads into the first named air inlet passage, the intention being to
prevent overheating of the said bed and to provide a constant current of heated
air. The said bed is kept covered with a layer of incandescent fuel, which may be
supplied at intervals from the fire grate.
And in order that our Invention and the manner in which we propose to carry
it into practical effect may be well understood, we have attached hereunto a Sheet
of Drawings illustrative of the application of our Invention to an ordinary
Lancashire boiler, the said Drawings being made to a scale of about one inch to the
foot, and marked with letters of reference. Referring to the said Drawings Fig. 1
represents a front end view of the boiler, and Fig. 2 a vertical longitudinal section
of one of the boiler furnaces. In the said Figs. a is the ordinary fire grate, b is an
air inlet grating, and c is the aforesaid bed of fire-clay, tiles, or refractory inaterial
which extends from the grate b to the bridge d. The grating b is also seen in plan 3
in Fig. 3, which represents a horizontal section of the furnace with the fire grate
removed in order that the air inlet damper may be seen. The grating bis
sustained by a casting e, in which is formed the aforesaid air inlet passage f. The
said casting also sustains a short floor g, formed of fire bricks or tiles, which floor
fills up the interval between the end of the fire grate and the inlet grating b, but 3
if preferred the fire grate and the grating may be brought nearer together so as to
dispense with the said floor. The mouth or forward end of the passage f is fitted
with a hinged damper h, which is connected by means of a rod with a
regulating apparatus which is attached to the front of the boiler. Any suitable
form of regulator may be used, but in order to render the illustration complete 4
we have represented a form of apparatus which we consider to be suitable,
but we do not make any claim in respect of the construction of such apparatus.
To the front of the boiler is attached a cylinder k, which is represented in section
drawn to a larger scale in Fig. 4. The said cylinder is provided with a piston l,
which is connected by means of a link with a lever m The outer end of the said 4
lever is connected by means of a rod with a lever, which is fixed upon a rocking
shaft n, and to the end of a second lever upon the same shaft is jointed the outer
end of the rod i, which is also connected with the damper. The lower end of the
cylinder is connected by means of pipes o, with a cistern p, which contains
water, oil, or other suitable liquid. One of the said pipes is fitted with a back 5
pressure valve which permits of a rapid flow of liquid into the cylinder when the
piston is raised, but prevents a return flow, and the other pipe is fitted with a
regulating cock which permits the slow return of the liquid to the cistern. A
chain r, which is led over pullies, is attached by one end to the lever m, and by the
other end to the furnace door 8, the arrangement being such as that when the

page_text: furnace door is opened the chain is caused to raise the said lever into the position
indicated by the dotted lines, whereby the piston in the cylinder k is raised. The
same movement of the said lever also effects the opening of the damper h. A
corresponding arrangement is applied to each furnace so that the description of one
applies to both. The operation of our Invention may be described as follows:-
At intervals, previously to the addition of fresh fuel, incandescent fuel is pushed
from the grate on to the bed so as to maintain thereon a layer of incandescent
fuel. When the furnace door is opened the damper h is also opened in the manner
previously herein described, whereby air is permitted to flow through the passage f,
and grating b as indicated by the arrows, such air becoming heated in its passage
through the space below the fire grate. A charge of fuel is introduced into the
furnace and the furnace door is closed, but the damper remains open owing to
the piston being supported by the liquid which it has withdrawn from the cistern.
Air is thus permitted to flow through the grating b, and to mingle with the
products of combustion passing from the space over the fire grate, and as the
mingled gases flow over the incandescent bed of fuel towards the bridge they
receive further heat, whereby the inflammable gases become consumed before
passing into the cooler rear flue, thereby preventing to a great extent the formation
of black smoke. As the liquid returns from the cylinder k, the damper h is
permitted to slowly close. Openings t, formed in the lower part of the casting e,
communicate with a space u below the bed c, and permit air to flow into the said
space as indicated by the arrow's. The heated air issues from the said space
through apertures at v into the inlet passage f. We may arrange for the damper h
to be opened by the closing of the furnace door instead of by the opening thereof.
We do not contine ourselves to the form or the use of the casting e, as the passage f
might be made in a brick wall, nor do we confine ourselves to the regulation of the
damper h by the opening or closing of the furnace door, as in some cases, as, for
example, in cases wherein self-acting stoking apparatus would be used the furnace
door would not require to be opened for the introduction of fuel into the furnace.
Having now fully set forth and indicated the nature of our said Invention and
the manner in which we carry the same into practical effect, we would have it to
be understood in conclusion that we claim,―
First. The furnace constructed and fitted substantially as and for the purpose
set forth and indicated herein before and in and by the accompanying Drawings.
Secondly. The bed to contain incandescent fuel formed between the fire grate
and the bridge, and the air grating or air inlet between the fire grate and the said
bed, substantially as and for the purpose set forth and indicated.
And, Lastly. The bed c, the air inlet b, the air passage f, and the damper h,
connected with a suitable damper regulator, substantially as and for the purpose.
set forth and indicated.
In witness whereof, we, the said Luke Shaw and Peter Thomas Fletcher,
have hereunto set our hands and seals, this Twentieth day of March, in the
vear of our Lord One thousand eight hundred and eighty-two.
Signed, sealed, and delivered in
the presence of
EDWARD K. DUTTON,
41, John Dalton St.,
Manchester,
LUKE SHAW.
(L.S.)
PETER THOMAS FLETCHER. (L.S.)
(Agent for the Patentees).