Year: 1888

page_text: I, ARCHIBALD THOMSON, of Springfield Mills, Alloa, in the County of Clackmannan,
North Britain, Manufacturer, 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, that is to say :-
My said Invention has for its object to improve the construction of mechanical
stoking apparatus, to simplify it, and to render its action more certain and efficient,
to increase its durability and render it less liable to derangement, and avoid the
obstruction of the front of the furnaces which is so objectionable in many existing
stokers.
My improved stoking apparatus is shown on two accompanying sheets of explanatory
drawings as applied to a single steam-boiler furnace. Figure, 1, on sheet, I, is a
longitudinal vertical section; and figure, 2, is a separate elevation of part of the
gearing. Figure, 3, on sheet, 2, is a front elevation, and figure, 4, is a transverse-
sectional view of a distributing plate. In these drawings the same reference numerals
are used to mark the same or like parts wherever they are repeated.
In carrying out my Invention I use longitudinal fire bars, 5, which are inclined so
as to be a little lower at their inner ends, which inner ends rest on a transverse
bearing plate, 6. The fire bars, 5, are alternately stationary and reciprocating, the
outer ends of the stationary bars being attached by bolts to a flange, 7, formed on a
front plate, 8; which covers part of the furnace front. The moving fire bars are at
their front ends supported by a transverse horizontal bearing bar, 9, which rests on
levers or arms, 10, fixed on a rocking shaft, 11, these arms, 10, being at the sides
of the ash pit, 12, so as to leave a clear space under the fire bars. The tops of the
arms, 10, which are by preference in separate adjustable pieces, are formed with slots
in which blocks on the ends of the bearing bar, 9, can slide to a small extent.
this arrangement the angular movements of the arms, 10, cause the bearing bar, 9,
and with it the movable fire bars, 5, to rise and fall to a small extent at the com-
mencements of the inward and outwaad movements respectively. The fire bars, 5, are
in transverse section shaped each like an inverted channel, slits being formed through
the middle of the top for the passage of air up from the channel space. Near the
front end of the furnace there is fixed a steam pipe, 13, which is fitted with a number
With

page_text: of small nozzles, 14, for directing jets of steam along the channel spaces of the
fire bars, 5, such steam jets inducing currents of air to pass along under the bars and
keep them comparatively cool whereby their durability is increased. A steam jet is
also directed to cause a current of air to pass along a pipe, 50, into the space beneath
the bearing plate, 6, to prevent that plate from becoming overheated. At the inner
end of each movable fire bar, 5, the inverted channel space is closed across to form
a short cavity in which a roller, 15, is placed to rest on the transverse bearing
plate, 6, and to bear the bar without frictionally resisting its movements; and the
bearing plate, 6, has small snugs cast on it to keep the fire bars from shifting
transversely.
The rocking shaft, 11, is worked by means of a lever, 16, fixed on it and con-
nected by a rod, 17, to a crank pin on a wheel, 18, which is fixed on a short shaft
carried in a bearing in the framing, 19, and is driven by a pinion, 20, on a shaft having
also on it a ratchet wheel, 21. The ratchet wheel, 21, is moved by a pawl, lever, 22,
to which a reciprocating motion is given by means of a rod not shown but which is
worked by an eccentric or crank on any convenient rotating shaft.
The coal is fed into the furnace from a hopper, 23, made with an inclined front, 24,
to guide the coal inwards towards the furnace, the space for the passage of the coal at
the bottom of the hopper being adjustable by means of plates, 25, attached to the
inner side of the hopper and which can be set to close the passage more or less by a
hand screw, 26. On reaching the bottom of the hopper, 23, the coal is pushed inwards
by a pusher, 27, which slides upon a horizontal plate, 28, fixed or formed across the
top of the furnace front, S. The coal is pushed inwards off the plate, 28, into
a distributing plate, 29, shown separately in figure, 4, and which can be adjusted
outwards or inwards to vary the opening between its inner edge and the front of the
boiler. Projecting from the middle of the inner edge of the adjustable plate, 29,
there are two oppositely inclined parts, 30, which by guiding portions of the coals
towards the sides prevent them from becoming too much heaped up at the middle.
At a lower position there is a second pusher, 31, which slides upon the plate or
flange, 7, up to which the stationary fire bars are bolted. The two pushers, 27, 31,'
are worked by one rocking shaft, 32, which is carried in bearings in flanges or
checks, 33, formed on or fixed to the front plate, S. On one end of this rocking
shaft, 32, there is fixed a lever, 34, which is made to reciprocate by a link, 35, con-
necting it to a crank pin, 36, adjustably fixed to a boss on the inner end of the shaft
of the wheel, 18. On the rocking shaft, 32, there are fixed two levers, 37, which are
jointed to lateral projections on the lower pusher, 31, and these levers are in the same
pieces with upper levers, 38, which work the upper pusher, 27. The ends of the
upper levers, 38, act between projections on the insides of the sides of the upper
pusher, 27, and a front plate, 39, connected to the pusher by a screw, 40, the position
of which determines the effective action of the levers on the pusher, as when the
screw, 40, is screwed outwards it allows increased play between the ends of the levers
and the parts they act on and vice versa. The action of the apparatus can thus be
varied and adjusted at several parts as may be found best in practice to suit different
kinds of coal and the requirements of each furnace.
Between the two pushers, 27, 31, there are two doors, 41, 42, which can be opened
by turning them inwards with their upper edges acting as axes. The upper door, 41,
which is a small light one made of sheet iron can by means of its handle, 43, be set in
any desired position, so as to admit more or less air over the fire and to allow the
condition of the fire being inspected at any time. The lower door, 42, is a larger
one for giving complete access to the interior of the furnace for any purpose, and it
can be opened by means of a lever handle, 44, (indicated by dotted lines in figure, 1,)
and which turns up a small lever, 45, on the inside of the cheek, 33, into a vertical
position so as to hold up the door when opened. On the plate, 7, on which the lower
pusher, 31, works there is fixed a small channel piece, 46, forming an entrance for
a little air and through which a poker can be used if required. The inner vertical
flange of the pusher, 31, is at its middle cut away to enable it to work over the
piece, 46.

page_text: The weight of the stoking apparatus including that of the front ends of the
fire bars, 5, is carried by independent frame standards, 19, and 49, any bolts connecting
it to the boiler simply serving to keep the apparatus in its proper position. In
applying the apparatus to two or more furnaces near together, many of the parts will
not require to be repeated some of them being merely extended.
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 I
claim is
1- The combination of parts constituting my improved stoking apparatus, sub-
stantially as herein before described.
2-The arrangement or combination of the fire bars and parts which support and
move them substantially as hereinbefore described.
3-The combination of parts constituting the coal feeding apparatus with their
adjusting and actuating details substantially as hereinbefore described.
Dated this Twelfth day of September 1888.
EDMUND HUNT,
Applicant's Agent.