Improvements in Apparatus for Mechanically Feeding Fuel to Furnaces.
Year: 1891

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus for Mechanically Feeding Fuel
to Furnaces.
JAMES WILLIAM CLARIDGE No. 22 The Waldrons Croydon in the County of
Surrey 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 invention relates to an improved mechanical stoker for intermittently
supplying fuel to steam boiler and other furnaces. The fuel may either be crushed
by suitable rollers as hereinafter described, or supplied to the hoppers already
broken or crushed. The object have in view being to obtain the advantages
hereinafter described which have been derived from experience and are as
follows:-
1st. To apply mechanical devices for intermittently feeding fuel to furnaces in
such a way as to leave the ordinary furnace door clear of gearing and accessible
for hand stoking when required..
2nd. To deliver the fuel periodically, and only when the firebars are in their
forward position.
3rd. By regular or variable motion of the fire bars depending upon the fuel
employed; to prevent the formation of clinker.
4th. To so construct and arrange the clinker plate and ash pit door, as that
both cannot be open together, thereby preventing cold air from entering the flues.
5th. To enable the fuel to be fed into the hoppers from several points in the
same or a separate bunker at the same time.
The means whereby I attain these objects will be clearly understood by reference
to the accompanying drawings in which:-
Fig. 1, is a front elevation of ordinary boiler, part of the casing being removed
from the furnace to the right hand.
Fig. 2, is a longitudinal section upon line A B Fig. 1, but shewing rod for
actuating clinker plate, stops, and first bar s, in its backward position.
Fig. 3, is an enlarged front and side view of rocking shaft and ratchet feed.
Fig. 4, is enlarged front and side view of device operating shutter.
Fig. 5, is a front, and side elevation to enlarged scale of motion shaft.
Fig. 6, is an enlarged side elevation shewing detail of fire bars, stops, and rockers,
the bar being respectively in the forward and backward position.
Fig. 7, is an enlarged side elevational view of cam, for producing a variable
motion of the bars in the forward and backward position.
Fig. 8, is an enlarged front elevation of same; the fire bars being removed and
the three cams being in the backward position.
Fig. 9, is an enlarged side elevation of device employed for short travel of first
bar in set.
Fig. 10, is an enlarged front view and plan of clinker plate, and ash pit door
shewn in Fig. 2.
Figs. 11, 12 are respectively a front view and plan of conveyors for feeding from
bunkers.
Fig. 13, shews the gearing employed to drive a set of horizontal and vertical
conveyors.
A, Figs. 12, are the hoppers, into which the coal or other fuel is fed by hand
or conveyor or by any other suitable means. Beneath each hopper are a pair of
star shaped crushing rolls a a, which are rotated by the shaft e, see enlarged
detail Fig. 3, this shaft is driven by the double pawlsff, which engage with the
ratchet wheel c, keyed thereto. Motion is imparted to the pawls which are pivoted
TD

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to the Jokes c', which are loose upon shaft e, by the movement of rod ell; The
quantity of coal passing through crushing rolls is increased, or decreased, by
altering the position of the knuckle joint ', mounted upon the stud b, which is
secured to the rocking shaft d, by means screw b. When the knuckle joint
is drawn out to the far end of the stud ", a greater travel is given to the pawls
and the ratchet wheel; and more fuel passes; and by pushing the knuckle joint
nearer to the shaft the supply is diminished. When it is required to altogether
stop the supply of fuel, the knuckle joint o¹ slides upon a stud mounted upon the
pin of a crank or dip formed in shaft d; by drawing the knuckle joint, inwards
until it coincides with the centre line of this shaft, no motion is imparted to the
rod c, and the supply of fuel is thereby stopped. When already broken or
crushed fuel is supplied to the hopper A, the star shaped rollers may be replaced
by a roller having plain grooves. The shaft d, see also Fig. 5, is mounted in two
bearings g², secured to the casing of boiler, and is driven by pulleys m m', one
of which m', is loose upon shaft. d, the other m, is formed with a sleeve m, upon
which is keyed the eccentric n, the rod of which n', is pivoted to the lever,
hinged at p, the outer end of lever o, is coupled by link to the lever r, keyed
to shaft d. Motion is imparted to the pulleys m, m', by belting connected to a
counter shaft or any other source of power; the reciprocating motion of shaft d,
can when more convenient be obtained direct from the eccentric n, provided the
rotating shaft or its equivalent actuating it, is in a suitable position.
After the coal has been crushed by the rollers it is retained by the shutter g",
and is allowed to fall upon the fire bars only when they are in the forward
position, see E, enlarged detail Fig. 6. I accomplish this by means of the mechanism
shewn in detail Fig. 4, and Fig. 1. Keyed to shaft d, is a collar and link d',
connected by rod 1, to the arm i, which runs loose upon the stud k, attached by a
bracket to casing. The armi, carries a small roller , which supports the cam
lever, keyed to the shaft, upon which the shutter ", is mounted. When the
arm i, is moved by the action of shaft d, and the lever connected thereto in the
direction of the arrow, the shutter falls and the coal is discharged upon the bars
when in their forward position. On the return of the shaft d, the respective parts
now referred to occupy the position shewn in the drawing.
The firebars see Fig. 1, 2, I prefer to arrange in sets of three s si s¹, but they
may be arranged in any other suitable manner. Each bar is mounted upon a
rocker t, mounted upon cross bars t". The bars can be arranged so as to be acted
upon singly or in sets. In the forward stroke each bar is below its neighbour;
thus when 8, bar is at its forward position as at E Fig. 6 it is below the next si su.
When sis in the forward position it will be below s, and level with s, and so on;
but in the backward movement they all move together; the fuel being by this
means carried steadily backward to the ashpit. This will be clearly understood
by reference to the enlarged detail in Fig. 6.
A series of cams are keyed upon the rocking shaft d, a slot or groove u' of equal
width being left upon the underside of each fire bars, These cams see dotted
lines C, Fig. 6, are of unequal width; but are set at the same angle upon shaft d,
so that their backs are in line. In the forward movement cam u, will first draw
forward bars, but cam ul, being of less width will not come into action until later,
cam, coming into action later still. Since all the cams are in the same line
at the back it follows that the whole of the bars will be returned together upon
the back stroke of the shaft. To preserve the independent action of each bar and
prevent its being moved forward by the side friction of contiguous fire bars, or by
the adherent fuel; I employ two stops v, which are pivoted upon the mounting just
beneath the furnace door. These stops are fitted with counter weights . Upon
cams ",, are small projections 2, which strike against the curved portion of
the stop v, and permit bars ss, to make the full travel. Upon the return stroke
the counter balance ', causes each stop to return to its original position as at C,
Fig. 6. No stop is required for the first fire bar s. In Figs. 7, 8 I shew the
devices employ for varying the travel of the fire bars. Each cam has a moveable
I

page_text: edge u, pivoted to it and connected by means of a link w, to a cross bar 20, which
is loosely pivoted axially but moves independently of the shaft d. The position of
the cross bar a, is shifted by means of handle y, and clamped in position by the
lock nut. By lowering the front edge u", of the cams they leave the slot ', in
the fire bars, before the full travel is completed. Fig. 9 shews a special form
of stop, which I use in front of the first fire bars. When the bars are making full
travel this stop is moved altogether out of the way by the action of moveable
edge, with partial travel it is so placed by the action of moveable edge u", as
that bars, butts against one or other of the notches, on the stop; with least
travel the stop, remains in place. The motion imparted to the fire bars has the
effect of carrying the ash and clinker to the back of the grate, and on to the clinker
plate y', supported by the standard ', which is hinged at w¹, see Figs. 2 and 10.
The standard, has pivoted to it a rod t, which after passing through the ash pit
doors is suspended from hooks in the bearers carrying the rockers t, terminating
in a loop at the firing end of the boiler. When the rod t', is drawn forward the
ash pit door, is, opened by the lug 2, the roller all upon standard a travelling
in the curved path upon the underside of clinker plate and holding it up. Upon
pushing back rod, it slides through hole in the ash pit door forcing back
standard, and allowing clinker plate to drop and discharge its ashes into the flue,
from which they are raked out in the ordinary manner. It will be seen that the
arrangement described effectually prevents the escape of cold air into the flue.
Figs. 11, 12, 13 shew the apparatus whereby I convey fuel from the bunkers to
the feed hoppers; the devices shewn enable coal, coke or like fuel to be drawn from
several parts of the same bunker, or from more than one bunker at a time. The
drawings show the arrangement I prefer to employ for marine purposes.
In the
drawings G, are the boilers, and A. the hoppers thereon, the bunkers. On any
convenient position I mount a line of shafting n', fitted with the requisite number
of mitre gears e and vertical conveyor shafts o" operating the conveyors p'. In
order to drive the horizontal conveyors p" by the mitre gear e', see Fig. 13, I
employ the spur gearing me, and when the horizontal shaft is not at right angles
to the vertical, I replace the mitre gear by bevels.
The operation of this part of my invention is as follows:-The vertical shaft
or either of them being set in motion by belt or otherwise, coal is brought by the
horizontal conveyors to the foot of the vertical conveyor p', and thence through
shoots o, into the hoppers A. By means of clutches n either pair of conveyors
can be disconnected at will. Although I have described the conveyors as suitable
for use on board ships, I do not thereby confine their use to this purpose only, as
they can be employed for drawing coal from any available source at sea or on shore.
In some cases the drawing conveyor may be vertical and feed into the horizontal
one, the former being on the bunker or equivalent, and the horizontal conveyor
on the top.
I am aware that mechanical stokers of the rotative distributor type have been
described in which one, or a set of fire bars are drawn forward collectively, or one
by one, by cams of uniform width which engage with latchets, or the like attached
to the fire bars, operated by a rotating shaft or the like device, the whole being
returned together by a separate set of cams, or by the same cams acting upon a
slide bar. I am also aware that a mechanical stoker, fuel crushing, and constant
feeding device combined with a tapering spiral conveyor operated by an escapement
ratchet motion has been described, but I lay no claim to either of these.
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. In apparatus for intermittently feeding fuel to furnaces, the particular
combination and arrangement of parts herein described for effecting the purposes
set forth.
2. In auparatus for mechanical stoking the combination and use of an eccentric

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mounted upon a sleeve actuated by a pulley or its equivalent keyed thereto, or
forming part thereof, said eccentric by means of the rocking lever o, connecting
rod, and crank, producing the required reciprocating motion in driving shaft,
for rocking the fire bars, driving the crushing rolls a, and operating 'the
shutter.g, so that the fuel may be delivered thereby upon the bars in the forward
position substantially as described.
3. In apparatus for mechanical stoking the variable ratchet device actuated by
the shaft d, for driving the crushing rolls a, substantially as described with reference
to Figs. 1, 2, 3.
4. In apparatus for periodically feeding fuel to boiler and other furnaces, the
application and use of a shutter ", for receiving the fuel from the crushing or
delivery rolls, said shutter being operated by the driving shaft d, by means of a
connecting rod, rocking lever, and cam in such a manner as that the fuel can only
be discharged from the shutter when the bars are in the forward position sub-
stantially as shewn in Figs. 1, 2, 4.
5. In apparatus for mechanical stoking constructed as herein described the
combination and use of fire bars mounted in sets upon rockers operated by 3 cams
of variable or unequal width fastened to reciprocating shaft, which engage in
succession with slots in the underside of the bars in the forward stroke but return
them together, substantially as herein set forth.
6. In apparatus for mechanical stoking constructed as described the use and
employment of the stops r, operated by the projections, upon cams, for
securing the full travel of fire bars, substantially as set forth.
7. In apparatus for mechanical stoking the combination and use of the particular
devices described under Figs. 7, 8, 9 whereby I vary the travel of the fire bars.
8. In a mechanical stoker the combination and use of the clinker plate y,
supported by the hinged standard, with the ash pit doors, both being so
connected and operated by the hand rod, as that they cannot admit cold air to
the fiue by being open together.
9. The combination and use with apparatus for mechanically feeding fuel to
furnaces of one or more pairs of conveyors, either the vertical, horizontal or
angular conveyor being as the case may be used for drawing or lifting fuel from
the bunkers, and feeding land or marine boiler furnaces in the manner described.
10. The combination and use with apparatus for mechanically feeding fuel to
furnaces' of one or more pairs of conveyors for drawing fuel from several points
in the same or different bunkers, and delivering the same to the furnaces the
drawing or feeding conveyors being either horizontal, vertical or angular as
described.
D TO 1901
FRANCIS M. ROGERS,
Agent