Improvements in the Construction of Furnaces for Steam Bollers and other Purposes and in Mechanical Stokers for Supplying the same with Fuel.
Year: 1887

page_text: Date of Application, 25th Nov., 1887
Complete Specification Left, 25th Aug., 1888
Complete Specification Accepted. 28th Sept., 1888
Improvements in the Construction of Furnaces for Steam Bollers
and other Purposes and in Mechanical Stokers for Supplying
the same with Fuel.
I, JAMES HODGKINSON of Woden Street, Ordsall Lane, Manchester in the County
of Lancaster, Engineer, do hereby declare the nature of my said invention to be as
follows:-
This invention relates to the construction of furnaces for steam boilers and other
purposes and in mechanical stokers for supplying the same with fuel, and consists in
providing transverse rocking or tilting and self-cleaning fire-bars of toothed or
other forms with the pivots or centres at each end of the bars placed out of the
centre to allow of the bars rocking or tilting in either direction for the purpose of
breaking up the fire or clinker, also for carrying the fire onto the next bar, or for
emptying or clearing the fire and ashes from the bars. The bars are provided with
double bearing surfaces for the fire, disposed at right or other angles, which allows
of the whole of the grate surface being renewed when one surface is burnt
out or almost destroyed by the action of the fire, thereby making a double
surface or reversible bar, effecting a great saving as each bar will last as long
as two of any other kind. The toothed or other forms are strengthened by ribs or
their equivalents. The bearings for the bars are provided in suitable side frames or
bars attached to the dead plate and bridge or otherwise. Suitable air spaces are
provided between the ends of the toothed or other forms of the bars and the back
side of the next bar. The bars are provided with tongues and centres to which is
attached a rod or rods for the purpose of rocking the bars alternately, in sets, or
altogether; the rod or rods extending to the front end of the furnace from whence
the bars can be operated by hand or power as desired. The rocking bars can be
placed so as to carry the fire or clinkers either towards the bridge or towards the front
end as may
be required. When employing my improved fire-bars for the purpose of
carrying the fire and clinker when working in conjunction with mechanical stokers
or otherwise the angular surfaces of the bars are connected by a sector piece cast

page_text: hollow or otherwise for the purpose of maintaining an uniform air space between each
bar and to prevent the body of the fire dropping through which would take place
owing to the slow movement at which the bars will require to be moved when self-
cleaning. In feeding the furnace with fuel from a mechanical stoker or its equivalent
it will be necessary to feed on a portion of the fire-bars only when it will be carried
the entire length of the tilting or rocking of the bars, which will deliver the fuel from
one bar to another in succession. When the face of one set of bars is burnt out, or
nearly so, they can be reversed so as to bring the other surface to the level of the fire,
the only additional being a fresh bar at each end of the furnace, thereby effecting a
great saving in both time and expense. In this arrangement I employ a combustion
chamber between the end of the grate surface and the bridge, which in the case of
rocking bars only 1 substitute therefor a cavity bridge supplied with air by
any suitable means from under the bars to effect and produce a more complete
combustion.
rams.
My improvements in mechanical stokers relate to those on the ram and coking
principle and have for their object the feeding of fuel in measured quantities which
can be increased or decreased at will. This I accomplish by providing a suitable
hopper into which the fuel is placed, and which is directed to one or more rams by an
inverted V or other piece. In the lower end of the hopper is placed a revolving
cylinder with pockets for delivering in measured quantities the fuel to the said ram or
If necessary the revolving cylinder can be utilized as a crusher by providing
a back plate or its equivalent, by which it performs the double function of measurer
and crusher. The ram or rams are disposed or mounted in guides, or in a casing, or
otherwise, and are operated by cams or other mechanical appliances to give a recipro-
cating motion, the same being adjustable to allow of the fuel being delivered in
varying quantities onto self-cleaning fire-bars. The crusher is mounted on a shaft and
driven with the ram or rams by tooth or other gear from any convenient part of the
machine. A door is provided so that hand firing may be resorted to when requisite or
for other purposes; the said door being lined on the inside by a fire resisting
medium.
In another arrangement I dispense with the revolving cylinder and pockets and
employ the ram or rams and a slide for giving a determined size of opening to the
outlet of the hopper, by which measured or stated quantities can be delivered at each
return stroke of the said ram or rams. The whole can be mounted on frame work
and fixed bodily to the front of the furnace, being fitted with bearings for carrying
the shafts and gear; also with bearings for carrying the gear for working the self-
cleaning fire-bars.
In another modification I dispense with the ram or rams and substitute therefor a
revolving beater with the blades directed from the central line of the boss to the
outside line, the angle being formed by one or more wings varied according to the
requirements of the furnace being fed and forming what is known as a fuel dis-
tributor. The crusher is provided with a reversible crushing and measuring plate
held in position by a spring or its equivalent; being in one position for crushing and
by reversing and blocking the opening the pockets of the crusher are filled with
fuel by gravity alone.
Dated the 24th November 1887.
EDMUND CHADWICK, C.E.,
92, St. George's Road, Bolton,
Agent for Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Construction of Furnaces for Steam Boilers
and other Purposes and in Mechanical Stokers for Supplying
the same with Fuel.
I, JAMES HODGKINSON of Woden Street, Ordsall Lane, Manchester in the County of
Lancaster, Engineer, do hereby declare the nature of my said invention and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement:-
This invention relates to the construction of furnaces for steam boilers and other
purposes and in mechanical stokers for supplying the same with fuel, and consists in
providing transverse rocking or tilting and self-cleaning fire-bars of toothed or other
forms with the pivots or centres at each end of the bars placed out of the centre
to allow of the bars rocking or tilting in either direction for the purpose of breaking
up the fire or clinker, also for carrying the fire onto the next bar, or for emptying
or clearing the fire and ashes from the bars. The bars are provided with double
bearing surfaces for the fire disposed at right or other angles, which allows of the
whole of the grate surface being renewed when one surface is burnt out or almost
destroyed by the action of the fire, thereby making a double surface or reversible bar,
effecting a great saving as each bar will last as long as two of any other kind. The
toothed or other forms are strengthened by ribs or their equivalents. The bearings
for the bars are provided in suitable side frames or bars attached to the dead plate and
bridge or otherwise. Suitable air spaces are provided between the ends of the toothed
The bars are provided
or other forms of the bars and the back side of the next bar.
with tongues and centres to which is attached a rod or rods for the purpose of rocking
the bars alternately, in sets, or altogether; the rod or rods extending to the front end
of the furnace from whence the bars can be operated by hand or power as desired.
The rocking bars can be placed so as to carry the fire or clinkers either towards the
bridge or towards the front end as may be required. When employing my improved
fire-bars for the purpose of carrying the fire and clinker when working in conjunction
with mechanical stokers or otherwise the angular surfaces of the bars are connected by
a sector piece cast hollow or otherwise for the purpose of maintaining an uniform air
space between each bar and to prevent the body of the fire dropping through which
would take place owing to the slow movement at which the bars will require to be
moved when self-cleaning. In feeding the furnace with fuel from a mechanical stoker
or its equivalent it will be necessary to feed on a portion of the fire-bars only when it
will be carried the entire length by the tilting or rocking of the bars, which will
When the face of one set of
deliver the fuel from one bar to another in succession.
bars is burnt out, or nearly so, they can be reversed so as to bring the other surface to

page_text: the level of the fire, the only additional being a fresh bar at each end of the furnace,
thereby effecting a great saving in both time and expense. In this arrangement I
employ a combustion chamber between the end of the grate surface and the bridge,
which in the case of rocking bars only I substitute therefor a cavity bridge supplied
with air by any suitable means from under the bars to effect and produce a more
complete combustion.
My improvements in mechanical stokers relate to those on the ram and coking
principle and have for their object the feeding of fuel in measured quantities which
can be increased or decreased at will. This I accomplish by providing a suitable
hopper into which the fuel is placed, and which is directed to one or more rams by an
inverted or other piece. In the lower end of the hopper is placed a revolving
cylinder with pockets for delivering in measured quantities the fuel to the said ram or
rams. If necessary the revolving cylinder can be utilized as a crusher by providing a
back plate or its equivalent, by which it performs the double function of measurer and
crusher. The ram or rams are disposed or mounted in guides, or in a casing, or
otherwise, and are operated by cams or other mechanical appliances to give a recipro-
cating motion, the same being adjustable to allow of the fuel being delivered in varying
quantities onto self-cleaning fire-bars. The crusher is mounted on a shaft and driven
with the ram
or rams by tooth or other gear from any convenient part of the
machine. A door is provided so that hand firing may be resorted to when requisite
or for other purposes; the said door being lined on the inside by a fire resisting
medium.
In another arrangement I dispense with the revolving cylinder and pockets and
employ the ram or rams and a slide for giving a determined size of opening to
the outlet of the hopper, by which measured or stated quantities can be delivered
at each return stroke of the said ram or rams. The whole can be mounted on frame-
work and fixed bodily to the front of the furnace, being fitted with bearings for carrying
the shafts and gear; also with bearings for carrying the gear for working the self-
cleaning fire-bars.
In another modification I dispense with the ram or rams and substitute therefor a
revolving beater with the blades directed from the central line of the boss to the outside
line, the angle being formed by one or more wings varied according to the require-
ments of the furnace being fed and forming what is known as a fuel distributer. The
crusher is provided with a reversible crushing and measuring plate held in position by
a spring or its equivalent; being in one position for crushing and by reversing and
blocking the opening the pockets of the crusher are filled with fuel by gravity
alone.
Fig. 1 is a longitudinal sectional elevation of my improved transverse rocking or
tilting fire-bars as applied to an ordinary internally fired steam boiler, and Fig. 2 is a
part plan of same.
In all the figures the same letters and numerals are used to indicate corresponding
parts.
A is the ordinary dead plate secured in the usual manner in the mouth of the boiler
flue B and C is the bridge plate. From the dead plate A and bridge plate Care
supported the side frames D provided with bearings to receive the pivots or centres E
of the rocking or tilting fire-bars G. The fire-bars are constructed with the double
bearing surfaces G, each surface being made of toothed form as in Figs. 6, 12, and 14,
or with slots as in Figs. 2, 9, 10, 15, and 18. The double bearing surfaces G can be
placed at right angles to each other as in Fig. 11, or at other angles as shown in
Figs. 1, 5, and 13. The object of providing the fire-bars with the double surfaces G
is to allow of the whole of the grate surface being renewed when one surface is burnt
out or partially destroyed by the action of fire by simply reversing the bars, thereby
making each bar to last as long as two bars of any other kind. Between the ends
of the toothed or other forms of bars and the back side of the next bar are formed
the air spaces K. The pivots or centres E are disposed in the centre of the bearing
surfaces G which constitute a double bar, or on the end of the surface carrying the
fire, which allows of the bars being rocked or tilted as in Fig. 3 for the purpose

page_text: of breaking up the fire or clinker. To the surfaces G of the bars hanging below
the fire are attached the tongues F with the centres H, which are coupled together
by the rod I; the latter being connected to the double lever J pivoted to the dead
plate A. When it is desired to carry the fire or clinker towards the front end of
the boiler the fire-bars G are disposed in the side frames D as shown in Fig. 1,
the movement of the same being effected by operating the lever J with a box key
or other suitable handle by hand or power as desired. In constructing my improved
fire-bars to carry the fire or clinker from one bar to another and on to the back
end of the furnace each alternate bar is coupled to the rod 1, the remaining bars
to the rod I as in Fig. 3; each rod being coupled to the levers J and J₁ respectively,
which are operated alternately by a box key or other suitable handle. In case it
is desired or necessary to clear the fire or clinker entirely from the fire-bars G the
latter are rocked or tilted until the fire or clinker is broken up, then the bars are
tilted to the position shown in Fig. 4 which will allow the contents to fall onto the flue
bottom underneath from whence they can be raked out.
In making my improved rocking or tilting fire-bars G as in Figs. 5 and 6 each
tooth or prong is strengthened underneath by the cast ribs L. When my improved
fire-bars are intended to be used in connection with mechanical stokers or otherwise
for the purpose of carrying the fire and clinker and are operated by mechanical
means to make them self-cleaning the angular surfaces G are connected by the
sector pieces M as in Fig. 7, for the purpose of maintaining an uniform air space
between each bar to prevent the body of the fire dropping through when in the
position shown in Fig. 8, which would take place owing to the slow movement at
which the bars will require to be moved. The surfaces G and between each sector
piece M are provided the air spaces K as in Figs. 9 and 10. In feeding the
furnaces with fuel from a mechanical stoker or its equivalent it will be necessary
to feed on a portion of the fire-bars only when it will be carried the entire length
of the furnace by the tilting or rocking of the bars as in Fig. 3, which will deliver
the fuel from one bar to another in succession. When the fire is delivered onto
the last fire bar and the same is tilted the fire will be emptied over the angular
bridge plate C into the combustion chamber N; the latter being between the end
of the bars and the bridge O. For the purpose of emptying the combustion
chamber N of clinker or ashes the door P hung from the bridge plate C is opened
When my
by means of the chain Q from the front of the boiler as in Fig. 3.
improved fire-bars are intended to be used only as rocking or tilting bars I substitute
for the combustion chamber N the cavity bridge R as in Fig. 1, the same being
supplied with atmospheric air by means of the door P hung from the bridge plate C,
the amount of opening being regulated by means of the chain Q from the front of the
boiler.
In another modification of my invention in lieu of the pivots or centres E I provide
the bars G with the open socket ends S as in Figs. 17 and 18. The open ended
sockets S sit on the pivots or centres E secured to the side frames D as in Figs. 15
and 16.
If desired my improved fire-bars can be constructed with one half of the bars
stationary and the other half movable, that is, that bars are placed alternately stationary
and movable throughout the entire length of the furnace. The stationary bars T are
provided with the square supporting ends U as in Figs. 11, 12, 13, and 14. The side
frames D are constructed with corresponding bearings to receive the square ends U.
The teeth or prongs forming the surface of the bars can be made to interlock each
other as in Figs. 11 and 12.
Fig. 19 is a front and sectional elevation of my improved mechanical stoker on the
ram and coking principle-Fig. 20 is a transverse sectional elevation, and Fig. 21
is a side view.
In the hopper 1 for receiving fuel is placed the revolving cylinder 2 mounted on the
crusher shaft 3*. The revolving cylinder 2 is provided with the pockets 3 for
delivering in measured quantities the fuel to the rams 4. The fuel in falling from

page_text: the revolving cylinder 2 is directed to the ram chamber 5 by the inverted V piece 6.
The rams 4 are mounted in the guides or ram chambers 5, in which they slide to and fro
to receive and deliver the fuel. Each ram is provided with the boss 7 to which is
coupled the links 8 and levers 9 by means of the pins 10. The levers 9 are mounted
on the shaft 11 supported in the bearings 12 attached to the framing 13. Motion is
imparted to the shaft 11 and rams 4 by means of the eccentric or cam 14 mounted on
the crusher shaft 3*, which is driven by worn or other gearing from any convenient
source or otherwise as desired. The eccentric or cam 14 is connected to the shaft 11
by means of the rod 15 and lever 16. The eccentric or cam 14 is made adjustable
for the purpose of varying the travel of the rams 4 to allow of the fuel being delivered
in varied quantities onto the self-cleaning or other fire-bars. On the revolving
crusher shaft 3× is mounted the block or sleeve 17 on which is fitted the eccentric or
cam 14 the eccentric or cam 14 is provided with the opening or slot 18 for the
purpose of receiving the block or sleeve 17, being sufficiently long to allow of the
travel of the eccentric or cam being regulated or varied according to the amount of
fuel required to be fed to the furnace. In the body of the eccentric or cam 14 is
formed the slot 19 in which is mounted the nut 20 on the screw 21, the latter being
fixed into the block or sleeve 17 by the pin 22. When it is necessary to alter the
stroke of the eccentric and rams it is accomplished by simply turning the
nut 20.
•
If necessary the revolving cylinder 2 can be utilized as a crusher by providing the
back plate 23 and spring 24 as in Fig. 23, by which it will perform the double function
of measurer and crusher.
To enable hand firing to be resorted to if necessary the door 25 is provided, which
can be lined on the inside with a fire resisting medium.
Fig. 22 is an arrangement wherein I dispense with the revolving cylinder 2 and
employ the rams 4 and the slide 26 for giving a determined size of opening to the
outlet from the hopper 1 to the furnace. The hopper 1 is constructed to receive the
slide 26, which is held and supported by the rod or rods 27. The rod or rods 27 is
fitted with the rack 28 which can be raised or lowered by means of a pinion from a
shaft placed in any convenient position above the hopper. The opening underneath
the slide 26 is regulated in size to admit stated quantities of fuel, the same being
pushed through into the fire by the forward movement of the ram or rams 4. The
slide 26 is lined with fire-bricks or other suitable fire-resisting medium 29. The ram
or rams 4 in this modification is reciprocated in the manner and by the mechanism
before described; the rod 15 coupling the same with an eccentric or cam on a shaft
above the hopper.
Fig. 23 is a modification of my invention wherein the ram or rams 4 are dispensed
with being substituted by the revolving beater 31 with the blades 32 directed from
the central line of the boss 40 to the outside line, the angles formed by the two
blades 32 varying according to the dimensions of the boss 40, and these dimensions
may advantageously be varied somewhat with the dimensions of the grate surface.
The boss 40 on the beater shaft 35 is provided with two or more blades 32 as shown
in Fig. 25 for distributing the fuel evenly on the grate surface. The even distribution
depends upon the form and direction of these blades. They may be varied somewhat
to adapt them to furnaces of different forms and sizes. The revolving beater 31 is
mounted on the beater shaft 35, and is driven as shown in Figs. 26 and 27. The
revolving cylinder or crusher 2 is provided with the reversible crushing and measuring
plate 23 held in position against the crusher 2 by the spring 24; the latter being
secured to the crusher box 33 by the set screw 34 or its equivalent. The spring 24
allows the crusher plate 23 to yield to any unusual strain and prevents the breakage
of the apparatus. When it is desired to use the plate 23 for simply measuring the
fuel in connection with the pockets 3 it is reversed as shown in Fig. 24, by which the
pockets 3 of the crusher 2 are filled with fuel by gravity alone.
For the purpose of regulating the throw of the revolving beater 31 the deflector
plate 36 is employed, the same being raised or lowered by means of the screw 37 and

page_text: nut 38. The fuel can be regulated in its supply from the revolving cylinder or
crusher 2 by means of the slide 39, which can be adjusted at will.
The supply of fuel is automatically regulated in this invention by the device shown
in Figs. 26 and 27, so as to keep any desired and uniform pressure of steam in the
boiler. This attachment to a nechanical stoker averts the danger of undue pressure
in the boiler, the waste of fuel, and the labor of an attendant. The fuel is supplied to
the furnaces as required to maintain the uniform pressure of steam.
The device for regulating the feed of fuel to the furnaces has a safety-valve 41,
suitably connected with the boiler Z. This safety-valve is weighted to any desired
pressure, and when the pressure in the boiler becomes greater the valve is opened and
steam escapes into the pipe 42 and operates on the diaphragm 43 and pin 44. The
rising of the pin 44 operates the lever 45 which disengages the clutch 46 on the
crusher shaft 3* and the swivel damper 47 by means of the levers 48 and rods 49,
which entirely stops the feeding device and checks the draught, which remain so until
the steam pressure assumes its normal state. When the steam pressure has arrived at
its normal state the valve 41 closes and steam escapes from the pipe 42 through the
exhaust pipe 50, by which the diaphragm 43 is released from pressure which allows
the lever 45 to drop by the weight 51, thereby operating the levers 48 and rods 49 by
which the clutch 46 is engaged and the swivel damper 47 is opened. The connection
of the valve 41 with the clutch 46 and damper 47 may be of any suitable description,
and fast and loose pulleys may be substituted for the clutch, the essential feature of
this regulating device being a valve which permits the steam to escape at a given
pressure and stops the feeding of the fuel and closes the damper, the feeding of fuel
commencing again and the damper opened as soon as the pressure in the boiler allows
the valve to close. The valve 41 can be fixed on the steam pipe 52, or to any other
convenient position on the boiler. This arrangement of clutch on the crusher shaft 3×
stops the feeding of fuel to the beater but allows of the speed of the beater being
maintained when it is always ready to distribute the fuel when supplied thereto. The
beater shaft 35 is driven by the belt 53 from the pulley 54 on the shaft 55, or in any
other suitable manner. The crusher shaft 3× is driven from the beater shaft 35 by
means of the worm gearing shown in Figs. 19 and 26.
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 use and construction of rocking or tilting fire-bars having double fire-bearing
surfaces of toothed or other forms with their pivots or centres disposed in the centre
of the bars so that the part bearing the fire will tilt upwards only in one direction
either forwards or backwards, substantially as and for the purpose herein described and
as shown on the drawings.
2. The use and construction of rocking or tilting fire-bars with the sockets S
disposed on each end so that they will tilt upwards when mounted on the pivots or
centres E, substantially as described and as shown on the drawings in Figs. 15, 16, 17,
and 18.
3. The use of the pivots or centres E secured to the side frames D as shown in
Figs. 15 and 16 for the purpose specified.
4. In combination with the rocking or tilting fire-bars with double fire-bearing
surfaces of tooth or other forms the use of the stationary bars T, substantially as
described and as shown on the drawings in Figs. 13 and 14.
5. The combination of alternate movable and stationary fire bars of tooth
form interlocking each other, substantially as described and as shown in Figs. 11
and 12.
6. The combination of parts forming my improved mechanical stoker on the ram
and coking principle, wherein the fuel is pushed on the fire-bars in measured quantities,
constructed and operating substantially in the manner described and as shown on the
drawings in Figs. 19, 20, 21, and 22.

page_text: 7. In mechanical stokers on the ram and coking principle the use of the revolving
cylinder 2 with the pockets 3 for delivering fuel in measured quantities, substantially
as described and as shown on the drawings.
8. In mechanical stokers the use, construction, and arrangement for adjusting
or varying the length of the stroke of the eccentric or cam 14 operating the rams 4,
substantially as and for the purposes herein set forth and shown.
9. In mechanical stokers the use of the reversible crushing and measuring plate 23,
applied and operating substantially as described and as shown on the drawings in
Figs. 23 and 24.