Improvements in or applicable to Mechanical Stokers and the Furnaces of Steam Boilers.
Year: 1893

page_text: Date of Application, 2nd Feb., 1893
Complete Specification Left, 29th Mar., 1893-Accepted, 29th Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in or applicable to Mechanical Stokers and the
Furnaces of Steam Boilers.
We RICHARD HARLEY WILLIAMSON of 21 Victoria Street, Ashton-under-
Lyne in the County of Lancaster, Joiner, and JAMES DYSON of Good Hope
Mill Ashton-under-Lyne in the County of Lancaster, Cotton Spinner, do hereby
declare the nature of this invention to be as follows:-
Our said invention relates to improvements in or applicable to apparatus for
automatically supplying coal or other fuel to the furnace of a steam boiler and
also to certain improvements in the internal arrangement or construction of the
furnace itself.
According to our said invention the coal is conveyed direct from a detached coal
bunker placed at some distance from the front of the boiler through the bottom
of the furnace preferably by means of an Archimedean screw or by means of
travelling ladders creepers or the like suitable devices. The coal is delivered
from the bunker to the conveyor intermittently by means of suitable measuring
or discharging devices provided with means for regulating their stroke or rapidity
of action or both so that the supply of coal to the conveyor may be adjusted to
suit the rate of combustion in the furnace.
We provide a delivery box at the end of the tube or conveyor casing so formed
that the fuel contained therein is partly coked. The delivery box is also so
constructed as to be capable of ready renewal when required and arranged to
co-operate with the system of reciprocating fire bara hereinafter referred to.
In combination with such a conveyor we use in the furnace reciprocating fire
bare to which a longitudinal motion is imparted by a suitable rocking shaft and
levers engaging with slots and notches or catches in the fire bars in such a manner
that while all the bars of a set advance simultaneously certain of the bars retire before
the others and thus while an intermittent agitation is produced a forward motion
of the fuel in continuation of that commenced by the conveyor is produced. The
interstices between the bars at the fore end of the furnace immediately bebind
the conveyor delivery box are covered with plates, blocks, bars or projections
attached to or forming part of the bars and partaking of their motion. By this
meaus a short coking stage is. formed to receive the fuel as it leaves the
delivery box.
The end of the said coking stage is so constructed that as it retires towards the
front of the furnace it passes under the rear of the delivery box the back face
or edge of which thus acts as a scraper and pushes the partly coked fuel forward
on to the bars behind the coking stage. At the end of the furnace farthest from the
delivery bok a transverse fixed plate or scraper block is provided under which the
ends of the bars pass.
The interval between the under surface of the said scraper block and the upper
surface of the bars is such as only to allow of the passage of ashes, clinkers, slag
and other like waste products of combustion. The upper layer of live or partly
burnt fuel is pushed back by the front face or edge of the said scraper block and
and thus the waste caused by the discharge of partly consumed fuel which attends
the use of reciprocating bars as heretofore employed is prevented. The scraper
block is corrugated fluted perforated or otherwise formed so that air heated in its
passage along the flue and through or under the said scraper block may be admitted
to the furnace at the rear end of the fire bars. The brickwork or other structure.
carrying the scraper block is preferably continued to the bottom of the flue

page_text: so as to prevent access of air to the flue beyond and below the level of the
fire bars.
In order to ensure a more advantageous distribution of the fuel in the furnace
the longitudinally reciprocating fire bars are arranged in three sets the central
set of bars being placed somewhat higher than those at the sides of the flue.
Filling up the spaces between the central set of hars and the side sets we inter-
pose inclined transverse bars set in such a manner that their angle of inclination
may automatically vary according to and compensate for the transverse expansion
or contraction of the longitudinal bars. Loss of fuel through the bars as well- na
injurious, transverse pressure on the sides of the flues is thus prevented.
Dated this 1st day of February 1893,
EDWARD TURNER WHITELOW,
70, Deansgate, Manchester, Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in or applicable to Mechanical Stokers and the
Furnaces of Steam Boilers.
We RICHARD HARLEY WILLIAMSON of 21 Victoria Street, Ashton-under-
Lyne, in the County of Lancaster, Joiner, and JAMES DYSON of Good Hope
Mill, Ashton-under-Lyne in the County of Lancaster, Cotton Spinner, 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:-
Our Baid invention relates in part to improvements in or applicable to the
invention for which Letters Patent were granted to Richard Harley Williamson
one of the present applicants dated the 12th of September 1891 and bearing the
official number 15518. We wish it to be understood that in our present Specification
we make no claim to anything described or claimed in the aforesaid Specification
of Richard Harley Williamson.
According to our present invention the coal is conveyed from a receptacle or
bunker (preferably placed at some distance from the front of the boiler) through
the bottom of the furnace by a suitable conveyor such for examplo as an
Archimedean screw or by means of a travelling lattice creeper to which the coal
is delivered from the bunker intermittently by suitable mensuring or discharging
devices provided with means for regulating their stroke or rapidity of action or
both so that the supply of coal to the conveyor may be adjusted to suit the rate of
combustion in the furnace.
We provide a delivery box at the end of the tube or conveyor casing sp formed
that the fuel therein is partly coked. The said delivery box is so constructed as
to be capable of ready renewal when required and is arranged to co-operate with
the system of reciprocating firo bars hereinafter referred to.
In combination with such a conveyor we use in the furnace reciprocating fire
bars to which a longitudinal motion is imparted by a suitable rocking shaft and
levers engaging with slots and notches or catches in the fire bars in such a manner
that while all the bars of a set advance simultaneously, certain of the bars retiro
before the others and thus while an intermittent agitation is produced a forward
motion of the fuel in continuation of that commenced by the conveyor is produced.
The intersticos between the bars at the fore end of the furnace immediately behind
the conveyor delivery box are covered by plates blocks bars or projections which
may he attached to or formed integral with the bars so as to partake of their
reciprocatory motion. By this means a short coking stage is formed to receive the
fuel as it leaves the delivery box on which the coking of the fuel (already
commenced in the delivery box) is continued so that by the time the fuel reaches

page_text: that part of the bars where the interstices are uncovered the small particles of
fuel being partly coked cohere and are less liable to fall between the bars.
The end of the coking stage is so constructed that as it retires towards the front
of the furnace it passes under tho platform of the delivery box at the upper end
of the conveyor tube. The back face or edge of the platform being stationary
pushes the partly coked fuel forward on to the bars behind the coking stage. At
the end of the furnace farthest from the delivery box a transverse fixed plate or
scraper block is provided under which the ends of the bars pass. The space
between the under surface of the said scraper block and the upper surface of the
bars is such as only to allow of the passage of ashes, clinkers, sing and other like
waste products of combustion while the upper layer of live or partly burnt fuel is
pushed back by the front face or edge of the said scraper block and thus the wasto
caused by the discharge of partly consumed fuel which attends the use of recipro-
cating fire bars in the manner heretofore employed is prevented. The scraper
block may be corrugated perforated or otherwise forined so that air heated in its
passago along the flue and past the said scraper block may be admitted to the
furnace at the rear end of tho fire bars,
The brickwork or other structure carrying the scraper block is preferably
continued to the bottom of the flue so as to prevent access of air to the flue beyond
and below the level of the fire bars.
In order to ensure a more advantageous distribution of the fuel in the furnace
the longitudinally reciprocating firebars are arranged in three sets the central set
of fire bars being placed somewhat higher than those at the sides of the flue.
Filling up the spaces between the central set of bars and the side sets we interpose
inclined transverse fire bara set in such a manner that their angle of inclination
may automatically vary according to and compensate for the transverse expansion
or contraction of the longitudinal bars.
Loss of fuel through the bars as well as injurious transverse pressure on the
sides of the flues is thus prevented.
In order that our said invention may be more clearly understood we will describo
the same in detail with reference to the accompanying drawings.
Figure 1 is a vertical elevation and Figure 2 is a plan (both partly in soction)
of the general arrangement according to one form of our said invention.
The remaining figures illustrate details and modifications or variations to suit
special applications of our said invention and will be referred to later..
In Figures 1 and 2 A is the flue of a steam boiler. B is the coal bunker or
receptacle at the lower part of which is a ram or piston a to which a reciprocating
motion is imparted by an excentric and shaft a'. The excentric rod a³ is provided
with a shoulder or groove taking into a slot in the ram a from which it may be
lifted by the action of the levers and links a' a' a' when it is desired to interrupt
the supply of fuel.
The fuel as it falls to the bottom of the bunker B is intermittently pushed
forward by the ram a and caused to fall into the conveyor tube or shoot c.
The rate at which the fuel is supplied to the conveyor may be readily varied
by altering the rate of rotation of the excentric at by shifting its driving belt
onto a larger or smaller pulley or by other well known means as will be well
understood. The fuel is conveyed along the conveyor tube c by the Archimedean
screw c to the delivery box the upper part of which is detachable so that
it may be easily replaced in case it becomes damaged by heat. The part of
the delivery box forms a platform on to which the fuel is discharged and where
it is partly coked by the action of the beat in the furnace and from which it
passes to the coking stage d'formed as hereinbefore set forth by projections on
some of the bars extending over the interstices between the other bars as shown
in section in Figure 3 in which each alternate bar is provided with a head or
flange reaching over the intervening spaces so that the small fuel cannot fall
through. The fire bars d have the longitudinally reciprocating motion herein-
before described and obtained by means which will be described in detail. As

page_text: they retreat towards the delivery box the coking stage d' passes under the plat
form of the delivery box the edge of which pushes the coked fuel off the
coking stage on to the part d. As the fuel renches the end of the bars d
it meets the scraper block e shown in frout elevation in Figure 5. The space e¹
is such as that only the clinkers, ash and the like waste products arising from
the combustion of the fuel can pass while the upper layers of unburnt or partly
burnt fuel are prevented from passing owing to being pushed back by the front
edge or face of the scraper block. Behind the scraper block the fluo is built
up at so that direct access of air to the flue beyond is prevented. Air passing
under the bars and under the scraper block or through the flutings or passages
therein is heated before its access to the furnace and meeting the gaseous products
of combustion immediately in front of the scraper block materially aids in the
perfect combustion of the fuel and the prevention of smoke. The lever for
operating the fire bars d derives its motion through the worm and worm wheel f
and the pulley from the counter shaft ƒ driven by suitable gearing from the
main shaft From the latter is also derived the motion for the screw conveyor
and for the reciprocating ram a by meaus of belts as will be understood from
Figures 1 and 2 without further description.
1
Tu plan in Figure 2 and in cross section in Figure 4 are shown the arrangement
of the three sets of fire bars herein before referred to for ensuring a more advan-
tageons distribution of the fuel. The central set of bars is somewhat higher than
the two side sets so that the fuel has a tendency to fall down against and to pile
itself more thickly against the sides of the flues by which the advantages of side
stoking which are well known to those practically acquainted with the use of steam
boilers is gained in combination with mechanical stoking. are the inclined com-
pensating bars hereinbefore referred to and which aro so set that as the longitudinal
bars expand or contract the inclined bars d vary their inclination and while
filling up the intervening spaces they relieve the sides of the flues from injurious
pressure.
We effect the reciprocating motion of the fire bars hereinbefore referred to in
several ways. In one arrangement shown in Figures 1, 4, and 6 it is obtained from
the rocking shaft g' (currying the levers f) (Figures 1 and 4) by means of the
link g carrying a cross bar passing through slots in suitable lower projecting
parts gg of each fire bar dor d'. Figure 6 shows these slots and their engaging
notches to a larger scale. Part of the fire bars are shaped as shown at 9³ and part
of them as shown at each kind of fire bar alternating with the other. g' is a
cross bar of steel or similar hard material let into the cross bar g³.
As illustrated in Figure 6 the cross bar g' is supposed to be receding in the
direction of the arrow and bearing against of the part 9 it is taking back all
the fire bars so shaped and is riding up the inclined plane but having a free
passage in the slot . All the fire bars shaped as remain stationary in their
forward position because the cross bar g' is at this stage provented from falling into
the notch g of the part 9 by the part of g. When the bars shaped as have
been drawn back, the cross bar 9 having been elevated can at its next forward
stroke ride over the top of the inclined plane and travel frocly along the slots h
and hª without advancing the fire bars. Meanwhile having escaped from the part gr
and having descended the inclined plane the cross bar drops in the notch 9 and
at the next backward stroke all the firo bars shaped as gare brought back.
While performing this operation the cross bar 9 has slid up and over the inclined
plane. Both sets of firo bars, that is those shaped as gand those shaped as g
are then in such a position that at the next forward motion of the cross bar gits
front edge bears against ' and which are now in line and both sets of fire bars
are carried forward simultaneously, whereupon the retrograde motion just desoribed
is repeated.
Figures 10, 11, 12, 13, and 13 illustrate another way of operating the fire bars.
In this case instead of making the slots in the fire bars themselves they are made.in
accessory bars or rods no which are operated by a link » actuated from the rocking

page_text: shaft g' (as in Figure 1). rr¹ are two rocking shafts each of which has a cranked
cross bars engaging with lugs under alternate fire bars. The rocking shafts are
operated by levers pivoted to the parallel bars no between which works the link p..
As the bars no are simultaneously drawn back in the direction of the arrow y the
fire bars are simultaneously advanced and as the bars no are successively pushed
forward in the opposite direction the fire bars are alternately caused to retire. The
proper motions are imparted to the bars no by the bolt or cross bar p² in the link p
taking into the slots and notches in the bars no as shown. The slots and notches
in n and o are respectively inclined and horizontal and when shaped as shown in
Figures 11 and 12 the effect in combination with the cross bar pr working therein
is that at one stroke of the link p in the direction of the arrow y both the bars no are
pulled in that direction so as to advance all the fire bars, while at other successive
strokes in the opposite direction 'the bars no are pushed forwards at different times
so as to cause the fire bars engaging with them to receive a corresponding retrograde
movement. A swinging plate staking against projections prevents the friction of
one of the bars n or o against the other carrying the other bar too far forward. In the
method of operating the bars last described the bars no are carried in a stirrup
in which they can rise and fall so that their notches may properly engage and
disengage with the cross bar p'. Figure 20 shows a modification of the devices last
described for operating the fire bars. In this case the inclined planes are dispensed
with and only a single cranked cross bar having its fulcrum at is used. The
cranked cross bar is operated by a link in the same manner as by the lever fas
described with reference to Figure 1. The cranked cross bar extends transversely
'under all the fire bars of the set. Each alternate bar is provided with projections.
with which the cross bar engages so that each alternate fire bar is positively
reciprocated at each oscillation of the cranked cross bar. The intervening loose
bars are not provided with projections engaging with the crank. The friction.
between the bars is however so great that as the driven bars are slid backwards and
forwards the loose bars when unimpeded are taken with the driven bars. In order-
to obtain the differential motion necessary for agitating and feeding forward the
fuel the loose bars are provided with lugs or stops as which take against.
suitable fixed parts as for instance oross bars whereby the movement of the loose.
bars is limited while the driven bars complete their course. All the bars thus
travel together at the first part of each stroke while at a lator part of each stroke
only the driven bars move.
We are aware that simultaneous and alternating motion of fire bars is well known
and we do not wish this part of our said invention to be construed as extending-
beyond the specific means we employ for effecting such motions.
Figures 7, 8, 9, and 9 illustrate a modification of our said invention for the
purpose of varying the rate of supply of fuel by varying the effective stroke of
the reciprocating ram already described with reference to Figure 1. In the
elevation, Figure 9 a¹ is the excentric (operated as shown in Figure 1) is the
excontric strap and excentric rod a pin k¹ of which engages with slots in levers
shown in plan in Figure 9. The other ends of the levers operate the rams a
for the purpose already described. The fulcrums of the levers are formed by
studs m at the ends of lovers m (Figure 8) suspended in stirrups m³ from the
bottom of the coal bunker. The studs m' take into holes in the levers P. By
means of the rod m³ provided with a screw and nut m'the position of the fulcrum m¹
and consequently the effective stroke of the rams a may be instantly varied so as-
to regulate the supply of fuel to the rate of consumption in the furnace.
In Figure 15 tho ram a for supplying measured quantities of fuel (depending on-
its size and traverse) at each stroke is operated vertically.
The means for imparting motion thereto through the lever a¹ may be by means.
of a crank or excentric as described with reference to Figure 1. In Figures 14
and 14 are rotating drums a"a" having buckets or vanes on their periphery so
as to form measuring receptacles to receive a dotormined quantity of fuel and to-

page_text: deliver it to the conveyor screw. By varying the velocity of these measuring
drums a greater or less quantity of fuel can be delivered to the conveyor.
Figure 16 shows an arrangement for discharging the fuel from the coal receptaclo
on to the conveyor screw which under some circumstances' we find very
advantageous as for example where it is inconvenient to place the coal receptacle
so low as is necessary when the arrangement shown in Figure 1 is adopted or when
the coal receptacle is necessarily at some distance from the front of the furnace.
Immediately under the bottom of the coal receptacle we provide a travelling lattice
creeper belt or sheet which may be provided with cross bars or plates ¹ as shown.
A sliding shutter or valve operated by a screwed rod and nut regulates the
depth of the layer of fuel convoyed on the travelling belt c. As the belt, returns,
the fuel thereon is discharged on to the conveyor screw c'.
=
Figure 17 shows a modified arrangeinent for supplying tho fuel simultaneously
to a number of conveyor screws. cc' represents the lower end of the conveyor
BCTOW. w is a trough having a reciprocating motion imparted to it in the directions
indicated by the double arrow w'. B. B are the coal bunkers each of which has a
prolongation extending from below the aperture to the bottom of the trough and
corresponding in shape to the cross section thereof so as to form an obstacle to
the passage of the fuel as the trough is slid in the direction of the arrow head to.
When however the trough is slid in the direction to the fuel last fallen from the
hopper is carried in the direction to and fresh fuel falls into the vacant space
behind. An intermittent forward creep of the fuel is thus caused until it reaches
apertures in the bottom of the trough over each conveyor sorew when its falls
through on to the screw c'. Anti-friction rollers * are provided for carrying the
trough which is actuated by a crank to and connecting rod w. Shutters or
valves to to with means for regulating their degree of opening as shown may be
provided for regulating the depth of the layer of fuel in the trough w.
Figures 18 and 19 show another arrangement we may adopt for supplying fuel
to a series of conveyor screws o' from one large coal receptacle placed at one end
of the range of boilers. This arrangement is particularly applicable where there
is, not sufficient space at the front of the boiler for placing the coal bunkers. as
shown in Figure 1. In this arrangement c'e' are the screws for conveying the fuel
into the furnace. Figure 18 is a couveyor screw working in a trongh w having
openings to immediately opposite cach conveyor screw c'. The fuel is taken from
the bunker B' by a travelling lattice or creeper to provided with suitable plates
projections or buckets " and delivered at into tlie trough w" along which it is
conveyed by the scrow to and distributed to the different openings ". Under
cach of these openings is a plate to sliding to and fro in the directions shown by
the double headed arrow. As the plate approaches the conveyor scrow, fuel
accumulates thereon but when the plato to" recedes the fuel is prevented from
receding by the part io" of the trough which pushes the fuel off on to the sorow c¹.
By this means there is produced an intermittent supply of fuel to the screw c¹ the
quantity of which may be regulated by the shutter 108 or the speed of the
creeper in
Having now particularly described and ascertained the nature of our said inven
tion and in what manner the same is to be performed wo declare that what
we claim is:—
.
1. The general arrangement construction and combination of parts comprising
the improved mechanical stoking apparatus as described generally with reference
to Figures 1 and 2 of the accompanying drawings and consisting of means for dis-
charging adjustable quantities of fuel from a fuel receptacle or heap isolated from
the furnace, for conveying the same into the furnace by means of a spiral conveyor
and for treating-burning and advancing the fuel through the furnace grate by
means of the heating box, coking platforms, front and back stop ledges, and
movable furnace bars, all arranged and acting for the purposes and substantially

page_text: as hereinbefore described and as indicated in the aforesaid figures and as modified
in Figures 7 and 19 of the drawings.
2. As adjuncts to and for use in combination with mechanical stoking apparatus
of the indicated description, for feeding the fuel from the receptacle to the con-
veyor screw, the reciprocating ram in combination with the means for operating
and throwing the same out of gear substantially as described with reference to
Figure 1; the means for operating and varying the effective atroke of such rams
as described with reference to Figures 7, 8, 9 and 9; the arrangement of ram
illustrated in Figure 15; the alternative endless feeding apron as shown in
Figures 16 and 19; the measuring wheel arrangements described with reference to
Figures 14 and 14ª; and the sliding trough device illustrated in Figure 17 of the
drawings.
3. In combination with a spiral or other feeder for delivering fuel beneath the
red hot fuel of a boiler furnace, the removable box c' with its ledge e' for coking or
partially coking the fuel as it is fed into the furnace substantially as described and
as illustrated in Figures 1 and 2 of the drawings.
4. In conjunction with mechanical stoking apparatus of the indicated nature the
described means for reciprocating the furnace bars as set forth and as illustrated
more particularly in Figures 1, 3, 4, 6, 10, 11, 12, 13, 134, and 20 of the drawings.
5. In movable furnace bars of the indicated description forming the front ends
of the bars directly in front of the ledge of the coking box, with overhanging or
projecting ledges so as to cover the interstices between the bars and so present a
platform to receive the freshly fed fuel and prevent it from dropping between the
bars until sufficiently coked, substantially as described and as shown in Figures 1,
3 and 4 of the drawings.
6. The ledge or its equivalent as a means for pushing the coked fuel from the
platform on the retraction of the bars, so as to feed the fuel forward in the
furnace substantially as described and as shown in Figures 1 and 2.
7. The stop ledge e at the back of the furnace grate to prevent unconsumed fuel
from falling over the ends of the furnace bars while permitting the ejection of ash
and small clinkers substantially as described and as shown in Figure 1.
8. In a furnace grate composed of series of bars at different lovels the employ-
ment of movable transverse bars to bridge the spaces between each series the anid
movable transverse bars being so mounted as to be capable of yielding to the
expansion and contraction of the grate substantially as described and as illustrated
in Figures 2, 3, and 4 of the drawings.
Dated this 28th day of March 1893.
EDWARD TURNER WHITELOW,
70, Deansgate, Manchester, Agent for Applicants.