Year: 1887

page_text: Date of Application, 23rd Nov., 1887
Complete Specification Left, 21st Aug., 1888
Complete Specification Accepted, 21st Sept., 1888
I, WILLIAM LEACH of 54 Paxton Street, Accrington, Lancashire Mechanical
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention has reference to what are called "mechanical stokers" employed for
the purpose of feeding fuel into the furnaces of steam boilers.
In carrying out my invention, I use the ordinary hopper, which may or may not be
provided at the bottom with a pair of rollers or porcupines employed to crush or
break the coal on leaving the hopper.
My improvements in mechanical stokers consist, in the use or employment of a
sliding feed box or boxes placed in a horizontal position and caused to reciprocate or
work backwards and forwards by means of a cranked stud or other equivalent or
mechanical contrivances. This feed box works at the bottom of the hopper and
receives a supply of fuel which it carries forward to one or more openings or apertures
through which the fuel drops and is received by a fan enclosed within a suitable box
or chamber, which fan throws the fuel forward into the furnace; but in order to
distribute the said fuel equally over the furnace bars, I employ an oscillating deflecting
plate or box suitably hinged and caused to rise and fall by a suitable arrangement of
cranks or cams and rods. This plate is hinged in front of a fan, and its forward end
is caused to rise and fall so as to determine the position at which the fuel shall be
thrown into the furnace, and this is accomplished in consequence of the deflecting plate
lessening or enlarging the orifice or outlet through which the fuel is sent by the fan;
therefore when the deflecting plate is down, the fuel is thrown near the entrance of
the furnace, but as the deflecting plate is raised the area of the outlet is enlarged,
allowing the fuel to be thrown further into the furnace, and this goes on until the
deflecting plate is at its highest point, when the fuel is thrown at the far end of
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page_text: the furnace. When this is done the deflecting plate begins to descend so as to guide
the fuel into other parts of the furnace. This deflecting plate may rise slowly, so as
to gradually feed the furnace from front to back, and then descend quickly so that the
feeding of the fuel may commence again at the front end of the furnace; or the
deflecting plate may descent slowly, in which case the fuel would be equally distributed
as the deflector opened and also when it closed. The deflecting plate and fan are
arranged at each side of the furnace and if required the deflecting plate may be of
angular or other shape so as to guide the fuel into the centre of the furnace as well as
to the sides thereof.
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page_text: I, WILLIAM LEACH, of 54 Paxton Street, Accrington, Lancashire, Mechanical
Engineer, do hereby declare the nature of this invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by the following
statement:
My improvements in mechanical stokers consist firstly, in the use and employment of
one or more sliding feed boxes for supplying fuel to the furnace; and, secondly, in
the employment of an oscillating deflecting plate or valve used for the purpose of
spreading the fuel equally on to the furnace bars.
In order that my invention may be better understood, I will now proceed to
describe the same more fully, and for that purpose make reference to the accompanying
sheets of drawings illustrative thereof.
Fig. 1 is elevation, shewing the application of my improvements to the flues A and B
of steam boilers.
Fig. 2 is a sectional elevation on an enlarged scale.
Fig. 3 is end view thereof, and
Fig. 4 is sectional elevation taken through the line a-b in Fig. 3.
At
The flues of the boiler are partly covered with a plate Chaving doors D and one or
more hoppers E for the reception of fuel, all arranged in the ordinary manner.
the end of each furnace are fans F placed in boxes or chambers G, such fans being
caused to revolve at any required speed by means of horizontal shaft H, driving
pulleys and strap I. The tops of the boxes G in which the fans revolve are made
with one or more openings, such openings being in direct communication with the
horizontal chamber J in which the feed box or boxes K are made to slide backwards
and forwards through the medium of the slotted rod L, in which works the stud M
projecting from the face of the spur wheel N, caused to revolve by means of worm 0,
fixed on the horizontal shaft H.
The reciprocatory feed box or boxes K are made with one, two, or more com-
partments Y and Z, so that when either one or other of the said compartments are
underneath the coal crushing rollers P, such compartment will receive a supply of
fuel so that on the rotation of the toothed spur wheel N the slotted rod will push the
feed box first over one fan and then over the other fan, consequently as the feed box
is made without a bottom the fuel therein will drop upon the revolving fans, which
will throw the said fuel forward into the furnace; but my improved deflecting plate
or valve, which is shewn at R, will regulate and determine in what part of the furnace
such fuel shall be sent, and this is effected in the following manner :-The deflecting
plate or valve R is hinged on a pin c, on which pin is fixed one end of the cranked
arm d, the opposite end of such arm being connected to the vertical rod e, on the
upper end of which rod is attached a plate f, such plate being slotted for the purpose
of allowing the short horizontal shaft g to pass through. A cam h is employed, fixed
upon the short shaft g, such said shaft being caused to revolve at a suitable speed by

page_text: means of worm and wheel i driven from upright shaft ; through the medium of a
wheel and worm k fixed on the horizontal driving shaft H. It will therefore be seen
that as the cam h revolves it will come into contact with a stud or friction pulley !
projecting from the plate f, consequently the upright rode will be made to rise and
fall, in doing which the deflecting plate or valve will be made to oscillate upon the
hinged pin c, causing such deflecting plate or valves to be raised and lowered in such
manner as to lessen or increase the size of the orifice or outlet through which the fuel
is sent by the fans. Therefore when the deflecting plate or valve is at its lowest point
as indicated in Fig. 3, the fuel is thrown near the entrance of the furnace, but as the
said deflecting plate or valve is raised the area of the outlet is enlarged, allowing the
fuel which impinges against the deflecting plate or valves to be thrown further into
the furnace, and this goes on until the deflecting plate or valve is at its highest point,
when the fuel will be thrown at the farthest end of the furnace. When this is done,
the deflecting plate or valve begins to descend, so as to guide the fuel into other parts
of the furnace. This deflecting plate or valve may rise slowly so as to gradually feed
the furnace from front to back, and then descend quickly so that the feeding of the
fuel may commence again at the front end of the furnace, or the deflecting plate or
valves may descend slowly, in which case the fuel would be equally distributed as the
deflector opened, and also when it closed, but the motion of the deflecting plate or
valves depends upon the form and shape of the cam which operates the parts. These
deflecting plates can be made either concave or convex, or angularly shaped.
By the employment of the double feed box and the deflecting plate herein shewn
and described, a perfectly self acting mechanical stoker is provided, which not only
equally distributes the fuel into the furnace, but requires very little attention on the
part of the workman, and although I have shewn and described the use of the crushing
rollers P, in some cases such rollers will not be necessary, as the style of feed box is
capable of receiving a supply of fuel sufficient for the fans to throw against the
deflecting plate or valve, which deflecting plate may be formed with a rib or a number
of projections as shewn at m, for the purpose of preventing the fuel from too easily
slipping off the said plate.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what 1
claim is :-
Firstly. In mechanical stokers, the employment of an oscillating deflecting plate for
assisting in the distribution of fuel into the furnace as shewn and described.
Secondly. In mechanical stokers, the combination therewith of a deflecting plate
and reciprocating feed box, arranged in the manner substantially as herein shewn and
described.
Thirdly. In mechanical stokers, the combination therewith of a deflecting plate,
revolving fans, and reciprocatory feed box, all arranged in the manner substantially as
herein shewn and described.
Dated this 20th day of August 1888.