Improvements in Mechanical Stokers for Steam Boller Furnaces.
Year: 1895

page_text: Date of Application, 26th Sept., 1895
Complete Specification Left, 20th June, 1896-Accepted, 29th Aug., 1896
Improvements in Mechanical Stokers for Steam Boller
Furnaces.
I, JOHN SMALLEY GRIMSHAW of Woodside House, Huncoat, near Accrington,
in the County of Lancaster, Gentleman do hereby declare the nature of this
invention to be as follows:-
The first part of my invention in mechanical stokers refers to prior Letters
Patent granted to William Leach on the 23rd day of November, 1887 No. 16096.
In the specification of the said patent particular reference is made to an oscillating
spreading plate employed for distributing the fuel equally between the entrance
and the bridge of the furnace. My invention consists in the application to the
said spreading plate of a V or U shaped bar so that on the fuel impinging against
the said bar, it will be diverted in an outward direction therefore in aldition to
the fuel being sent forward into the furnace it will be also distributed outwardly
against the Blues of the furnace consequently the distribution of the fuel will be
uniform. Instead of the V or U shaped distributing bars being applied to an
oscillating plate as already mentioned they may be connected to a stationary
plate.
The next part of my invention refers to the fans employed to deliver the
coal into the furnace. In practice I have found that the said fans are sometimes
broken and otherwise damaged by hard substances which from time to time get
into the fan box. The object of my invention therein is to construct and arrange
and apply the said fans in such a manner that they can revolve for the purpose
of supplying coal, but that when hard substances are in the fan box the said fan
will give way and cease to revolve whereby breakages are prevented.
In carrying out my invention the blades of the fan are placed loosely upon the
fan shaft, which is driven at a great velocity carrying the blade of the fan with
it by centrifugal action, but when any hard substance blocks up the fan box the
blades of the said fan will cease to revolve notwithstanding that the fan shaft is
continuing to rotate. As soon as the impediment in the fan box is removed the
wings of the fan will again revolve through the speed of the shaft upon which
they rest. The next part of my invention consists in means to be employed for
driving the fan which I propose to do by cone drums or cone pulleys.
By this
means the speed of the fan and consequently the supply of coal to the furnace
can be regulated by moving the driving strap or driving cord ou the said cones
from one speed to another.
Dated this 25th day of September 1895.
TASKER & CROSSLEY,
Halifax, Patent Agents.

page_text: Improvements in Mechanical Stokers for Steam Boiler
Furnaces.
I, JOHN SMALLEY GRIMSHAW, of Woodside House, Huncoat, near Accrington,
in the County of Lancaster, Gentleman, 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 :-
The first part of my invention in mechanical stokers refers to prior Letters
Patent granted to William Lench on the 23rd day of November, 1887,
No. 16,096.
In the specification of the said patent particular reference is made to an
oscillating spreading plate employed for distributing the fuel equally between the
entrance and the bridge of the furnace.
:
My invention consists in the application to the said spreading plate of a V or
Ushaped bar, so that on the fuel impinging against the said bar, in addition to
being sent forward into the furnace, it will be diverted in an outward direction
against the sides of the flues of the furnace, and consequently distribute the fuel
more uniformly over the fire. Instead of the V or U shaped distributing barg
being applied to an oscillating plate as already mentioned they may be connected
to a stationary plate.
The next part of my invention refers to the fans employed to deliver the coal
into the furnace. In practice I have found that the said fans are sometimes
broken and otherwise damaged by hard substances which from time to time get
into the fan box. The object of my invention therein is to construct and arrange
and apply the said fans in such a manner that they can revolve for the purpose
of supplying coal, but when hard substances are in the fan box, the said fan will
give way and cease to revolve whereby breakages are prevented.
In carrying out my invention the blades of the fan are placed loosely upon the
fan shaft which in revolving carries the blades of the fan with it by centrifugal
action, but when any hard substance blocks up the fan box the blades of the said
fan will cease to revolve notwithstanding that the fan shaft is continuing to
rotate. As soon as the impediment in the fan box is removed the wings of the
fan will again revolve through the speed of the shaft upon which they rest.
My invention further consists in means to be employed for varying the
delivery of fuel to the furnace, which I propose to do by cone drunis or cone
pulleys.
By this means the speed of the parts and consequently the supply of coal to
the furnace can be regulated by moving the driving strap or driving cord on the
said cones from one speed to another.
For the purpose of fully describing and ascertaining my said invention,
reference is hereafter had to the annexed sheet of drawings forming a part of this
specification in which :-
Fig. 1 is elevation of a mechanical stoker embodying my improvements.
Fig. 2 is enlarged plan of same taken on line 1-2.
Figs. 3 and 4 are enlarged transverse sections taken respectively on lines 3-4
and 5-6 of Fig. 1.
Fig. 5 is end elevation, Fig. 6 front elevation and Fig. 7 plan of underside of
the fuel spreading and distributing plate.
Fig. 8 is end elevation, and Fig. 9 front elevation of loose rotary fan constructed
according to my invention.
The same letters of reference indicate corresponding parts throughout.
Referring to the drawings, letter A denotes the boiler front, B the ashes place,
C the furnace doors, A the part to which the stoker is bolted, E the fau boxes,

page_text: F the shaft on which the fans are mounted, said shaft being provided
with fast and loose pulleys F, G the spreading plates situated in the furnace
and over the outlet ends of the fan boxes, H the rakes for pushing coal
to the several fan boxes, I the hoppers containing the supply of fuel, and J the
double ended rod for assisting the deposit of coal in the fan boxes and preventing
the outlets from choking up. The rakes H are attached to lever K, centred
at K¹, said lever being oscillated to give reciprocatory motion to the rakes, by
means of a stud L, fast to the worm wheel M, and engaging with the sides of a
recess or groove formed in the rear of the lever K, the worm wheel M being
driven by worm N. on shaft N¹, which derives motion by cord or belt N³, from
the driving shaft F of the stoker.
upper end
The rod J is also reciprocated by the lever K whose
at each
engages
oscillation with one of the fingers or lugs J¹, fast on the said rod, and gives it the
requisite amount of traverse in each direction. The springs O, lying on rod J.
and between the lugs J and upper end of lever K are employed to prevent:
breakages when a large piece of coal gets into the hopper I, the said rod J under
such conditions yielding and thus a breakage of the lever K or some other part is.
prevented.
The above is common to a Leach's stoker (with the exception of the springs
between lugs J and lever K) and forms no part of my invention, the first part of
my invention referring to the plates G for spreading coal on the fire and the
improvement consists in the application to the underside of said plates of V or
Ushaped bars or projections a attached to or formed integral therewith, somewhat.
as shewn in Figs. 5, 6 and 7. The fuel, when thrown by the fans out of the fan
boxes, impinges on the bars or projections a which divert the coal in an outward
direction toward or against the flues of the furnace as indicated by arrows in Fig 2,
and consequently distribute the fuel more uniformly over the fire.
The spreading plates are oscillated to distribute the fuel from front to back of
the furnace by rods and levers 6 actuated by cam groove e formed in the toothed.
wheel which is driven by pinion e on the rear of the worm wheel M.
Instead however of the V or U shaped distributing strips a being applied to an
oscillating plate, the said distributing strips may be connected to or formed on a
stationary plate.
The next part of my invention refers to means for preventing breakages where
hard or large substances get into the fan. boxes, and cannot be discharged by the
fans, said means consisting of fan blades f, f', secured in the form of a hinge by
pins, studs, or cotters g, to caps h, h', or opposite portions of a split collar, placed
loosely on the fan shaft F and nipped together by screws i somewhat as shewn
in Figs. 8 and 9.
The connection between the fan blades f, f' and caps h, h¹, is sufficiently tight.
as, in conjunction with the centrifugal action of the fan shaft to ensure the
removal and delivery of the coal to the furnace under normal conditions, but under
abnormal conditions as when any hard substance gets into the fan box and cannot.
be removed without some part being broken or otherwise damaged, the blades f, fƒ³,
will on encountering it, give way to the obstruction and be forced round on their
connecting pins g as on a pivot and thereby avoid breakage.
If the block in the fan box is more than this will accomplish the caps or split
collar to which the blades are attached will give way to the obstruction aud.
cease rotating notwithstanding that the fan shaft continues its rotation.
For further safety I employ a loose slide or door K at the bottom of the fan.
box which will give and open out when pressure is exerted thereon by any large
substance deposited in the fan box.
The last part of my invention consists in means for increasing or lessening the-
supply of fuel to the furnace.
On the fan shaft F I mount a cone drum or pulley and a like cone drum or
pulley m is mounted on the worin N¹.:
A cord or belt N' is passed over the cone pulleys to convey motion from

page_text: shaft F to shaft N¹, and by moving said driving cord or strap from one speed to
another on said cones, the rakes H, rod I and spreading plates G are moved
quicker or slower as the case may be, the supply of fuel being thus increased or
lessened and the spreading of it over the furnace accelerated or retarded
correspondingly.
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 :-
Firstly. In mechanical stokers, the use of an oscillating or stationary spreading
plate G, having shaped bars or projections on the underface thereof, for diverting
fuel outwardly to the sides and over all the furnace substantially as shewn and
described.
Secondly. In mechanical stokers, the construction of fans adapted to rotate
with the fan shaft under normal conditions, and to give to obstructions or hard
substances deposited in the fan boxes in the manner and for the purposes
substantially as herein shewn and described.
Thirdly. In mechanical stokers, the combination with a loose fan such as herein
shewn and described of a loose slide or door K at the bottom of the fan box for
purposes substantially as set forth.
Fourthly. In mechanical stokers, the combination with the reciprocating rod H
and rod J of spring O for purposes described.
Fifthly. In mechanical stokers, the application of cone drums or pulleys for
varying the supply of fuel substantially as herein shewn and described.
Dated this 19th day of June 1896.
TASKER & CROSSLEY,
Halifax, Patent Agents.