Improvements in Mechanical Stokers.
Year: 1894

page_text: Date of Application, 19th Oct., 1894-Accepted, 24th Nov., 1894
COMPLETE SPECIFICATION.
Improvements in Mechanical Stokers.
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
and suitable for large or small coal 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 an accompanying sheet of explanatory
drawings as applied to a steam boiler with two furnaces; Figure, 1, being a front
elevation, and Figure, 2, a longitudinal vertical section.
In these drawings the same reference letters and numerals are used to mark the
same or like parts wherever they are repeated.
In carrying out my invention I use longitudinal fire bars, A, which are con-
structed, and carried at their inner ends, in the manner described in my earlier
Patent Specification No. 13,238 of 1888. The fire bars, A, are alternately
stationary and reciprocating, the outer ends of the stationary bars being secured
by bolts to a channel-iron bar, B, bolted to the side frames, H. The moving fire
bars are at their front ends supported by a transverse horizontal bearing bar, C,
which rests on levers or arms, C 1, fixed on a rocking shaft, D, these arms, C 1,
being at the sides of the ash pits, D 1, so as to leave a clear space under the fire
bars.
The rocking shaft, D, is worked by means of a lever, E, fixed on one end
of it and connected by a rod, E 1, to a crank pin, E 2, on a wheel, F, which turns
loosely on one end of a transverse shaft, G, carried in bearings in the framing, H,
and is driven by a pinion, J, on a shaft having also on it a ratchet wheel, K. Or
the rod, E1, may be dispensed with, the crank pin, E 2, acting directly on the
lever, E, into a slot in which it projects. The ratchet wheel, K, is moved by a
pawl lever, L, to which a reciprocating motion is given by means of a rod, M,
attached to the outer end of the pawl lever, and worked by an eccentric or crank
(not shown) on any convenient rotating shaft. With this arrangement, which is
similar to what is described in my earlier Specification hereinbefore referred to, the
desired motion is given to the movable fire bars.
The coal is placed in, and fed into each furnace, from a rotating hopper, N,
carried on the transverse horizontal shaft, G, which is made to rotate at a slow
speed suitable for the kinds of coal used and to the requirements of the furnaces,
through a wheel, F 1, keyed on it near its right-hand end being driven by a
pinion, J 1, on a shaft having on its other end a ratchet wheel, K 1. The ratchet
wheel is moved by a pawl lever, L 1, to which a reciprocating motion is given by
means of a rod, M 1, attached to the outer end of the pawl lever, L 1, and worked
by an eccentric or crank (not shown) on any convenient rotating shaft. Each
hopper, N, is divided into four (or other) suitable number of compartments by
partitions, P, one of which is hinged at, P 1, so that it can be turned into the
position shown by dotted lines in Figure, 2, to allow of the condition of the fire
being inspected and forming an entrance through which a poker or other instrument
can be used if required. The through opening thus formed can also be used for
lighting the fire or for firing by hand when the driving shaft is not working. A
bandle, Q, is fixed on the ratchet wheel, K1, to permit of the hoppers being
turned into the desired position when required. The circumference of each

page_text: rotating hopper, N, is partly enclosed by a casing made in two pieces, R1, R2,
the lower piece, R 2, being shown removed at the right hand side of Figure, 1.
This lower casing, R 2, serves to retain the coal in each compartment of the hopper
whilst that compartment is inverted and until the coal leaves the compartment and
is acted on and pushed inwards by the partition plate, P, and afterwards by a
pusher, S, which slides upon the outer ends of the fire bars, A. The pushers are
each connected at, S 1, to two sectors or bell cranks, T 1, T2, centered loosely on
the transverse shaft, G. These sectors, T 1, T2, are connected through by pins, T 3,
to rods, U, extending down and connected to levers, W, on the rocking shaft, D.
With this arrangement, the rocking shaft, D, imparts the desired reciprocating
motion to the pushers.
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 and arrangement of parts constituting my improved
mechanical stoking apparatus substantially as hereinbefore described.
2. In mechanical stoking apparatus, a slowly rotating hopper to which large or
small coal is supplied and which in rotating delivers the coal into the furnace, the
parts of and accessory to such hopper being constructed, arranged and operating
substantially as and for the purposes herein before described.
Dated this Eighteenth day of October 1894.
EDMUND HUNT,
Applicant's Agent.