Improvements in Mechanical Furnaces or Grates.
Year: 1891

page_text: Date of Application, 7th Nov., 1891
Complete Specification Left, 8th Aug., 1892-Accepted, 5th Nov., 1892
PROVISIONAL SPECIFICATION.
Improvements in Mechanical Furnaces or Grates.
We, HENRY EDWARD BEDFORD, of Waltham Buildings. Holborn Circus,
London, E.C., Engineer, and JAMES LYONS SAMPSON, of 274, Oxford Street,
London, W.C., Engineer, do hereby declare the nature of this invention to be as
follows:
:-
This invention has reference more particularly to those classes of furnaces or
grates known as mechanical furnaces or grates in which travelling fuel bearers are
employed, and convey fuel from one end thereof, onto which it is fed in a green
state, forwards toward the opposite end, the feed being so regulated that by the
time any part of the bearers, onto which the fuel is fed, reaches the end of the
furnace, the fuel so fed will be practically completely burned, ashes and clinker
only being discharged at the back end. And the object of this invention is more
particularly to provide mechanical furnaces or grates which shall be applicable to
what are known as internally fired steam generators, such as Cornish and Lanca-
shire boilers, and their equivalents, but which, at the same time, shall be susceptible
of application to other furnaces.
For convenience and simplicity of description, we will set forth the nature of
our invention as applied to Cornish, Lancashire, or equivalent types of boiler, it
being understood that the features of the invention are applicable also to other
furnaces.
The fuel bearers of the furnace consist of a plurality of transverse bars having
on both sides, a number of projecting teeth or provisions, the teeth of the alternate
bars being so arranged as to lie within the spaces between the teeth or projections
of those adjacent to them. The bars are connected together at each side by
trunnions, and links, connecting said trunnions together. The links may be kept
upon the trunnions, in some cases, by pins passing through the link, and grooves in
the trunnions. The bars so fastened form or constitute an endless carrier or
conveyor.
This endless conveyor consisting of the interconnected bars above described, is
mounted on rollers or pulleys at each end, and such rollers or pulleys are mounted
on and work in side frames or girders running from end to end of the furnace, and
connected together transversely, at suitable distances, by bars or the like. The
side frames are also adapted to support the fuel bearers between the rollers or
pulleys above mentioned.
Between the side frames, and running longitudinally, we provide bars or
equivalent means by which any fire-bars which become broken, are prevented from
failing out of place or position, and deranging the other bars and parts of the
furnace.
In connection with the frame at the front of the furnace, is provided a hopper
for containing fuel, and automatically delivering it onto the fuel bearers. And
there is also provided in connection with this part of the furnace or grate, a sliding
or moving door, curtain, or partition, by which the quantity of fuel fed may be
controlled, and the gearing by which the endless fuel bearing conveyor is
operated.
The whole furnace or grate including the frames, hopper, gearing, fuel bearers,
and other parts, are supported upon wheels at the front and back end (and at
intermediate points, if desired), and can thereby be moved or run completely in and
out of the steam generator or other furnace, as desired.
At the back end of the furnace or grate, a suitable bridge is provided, and in
connection with this we provide a hinged or movable plate or device by which

page_text: excess of air is prevented from flowing past the end, and at the same time allows
free movement of the fuel bearers and discharge of clinker and ash.
In connection with the frames of the furnace or grate, we provide conduits (for
instance pipes) by which circulation of water may be caused to be maintained
through the frames and keep them and other parts in, or working in connection
with them, cool. And by this means also, the furnace or grate may be entirely
disconnected from, or unattached to, the furnace tube when applied to a steam
generator.
At the front end and just above the fuel bearers, we provide a firebrick arch by
which the fuel is partially coked, and coinbustion at the front end is facilitated.
Suitable tooth or like gear is provided to work the movable curtain and the grate,
and means is provided by which the tension of the grate conveyor is adjusted, and
the height thereof regulated.
The construction and disposition of parts above specified may be modified and
differently carried out, and their equivalents used without departing from the
spirit.or scope of the invention, the nature of which has been above described.
Dated thie 6th day of November 1890.
CHEESBROUGH & ROYSTON, Fels. Chart. Inst. P.A.,
15, Water Street, Liverpool, Applicants' Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Mechanical Furnaces or Grates.
We, HENRY EDWARD BEDFORD, of Waltham Buildings, Holborn Circus,
London, E.C., Engineer, and James Lyons SamPSON, of 274, Oxford Street,
London, W., 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 :-
This invention has reference more particularly to those classes of furnaces or
grates known as mechanical furnaces or grates, in which travelling fuel bearers are
employed, and convey fuel from one end thereof on to which it is fed in a green
state, forwards, toward the opposite end, the feed being so regulated that by the
time any part of the bearer, onto which the fuel is fed, reaches the end of the
furnace, the fuel so fed will be practically completely burned, ashes and clinker
only being discharged at the back end. And the object of this invention is more
particularly to provide mechanical furnaces or grates which shall be applicable to
what are known as internally fired steam generators, such as Cornish and lanca-
shire boilers, and their equivalents, but which, at the same time, shall be susceptible
of application to other furnaces.
For convenience and simplicity of description, we will set forth the nature of
our invention as applied to Cornish, Lancashire, or equivalent types of boiler, it
being understood that the features of the invention are applicable also to other
furnaces.
The fuel bearers of the furnace consist of a plurality of transverse bars having
on both sides, a number of projecting teeth or projections, the teeth of the alternate
bars being so arranged as to lie within the spaces between the teeth or projections
of those adjacent to them. The bars are connected together at each side by
trunnions, and links, fitting over said trunnions. The links may be kept upon
the trunnions, in some cases, by pins passing through the link, and grooves in
the trunnions. The bars so fastened form or constitute an endless carrier or
conveyor.
This endless conveyor consisting of the interconnected bars above described, is
mounted on rollers, drums or pulleys at each end, and such rollers, drums, or
pulleys are mounted on and work in side frames or girders running from end to end
of the furnace or grate, and connected together transversely, at suitable distances,

page_text: by bars or the like. The side frames are also adapted to support the fuel bearers
between the rollers, drums or pulleys above mentioned.
Between the side frames, and running longitudinally, we provide bars or
equivalent means by which any fire bars which become broken, are prevented from
falling out of place or position, and deranging the other bars and parts of the
furnace.
In connection with the frames at the front of the furnace, is provided a hopper
for containing fuel, and automatically delivering it onto the fuel bearers. And
there is also provided in connection with this part of the furnace or grate, a sliding
or moving door, curtain, or partition, by which the quantity of fuel fed may
be controlled, and the gearing by which the endless fuel bearing conveyor is
operated.
The whole furnace or grate including the frames, hopper, gearing, fuel bearers,
and other parts, are supported upon wheels at the front and back end (and at
intermediate points, if desired) and can thereby be moved or run completely in and
out of the steam generator or other furnace, as desired.
At the back end of the furnace or grate, a suitable bridge is provided, and in
connection with this we provide a hinged or movable plate or device by which
excess of air is prevented from flowing past the end, and at the same time allows
free movement of the fuel bearers and discharge of clinker and ash.
In connection with the frames of the furnace or grate, we provide conduits (for
instance, pipes) by which circulation of water may be caused to be maintained
through the frames whereby they and other parts in, or working in connection with
them, are kept cool. And by this means also, the furnace or grate may be entirely
disconnected from, or unattached to, the furnace tube when applied to a steam
generator.
At the front end, and just above the fuel bearers, we provide a firebrick arch by
which the fuel partially coked, and combustion at the front end is facilitated.
Suitable tooth or like gear is provided to work the movable curtain and the grate;
and means are provided by which the tension of the grate conveyor is adjusted.
In the drawings, which serve to illustrate our invention,
Figure 1 is a longitudinal sectional elevation of our improved grate or furnace as
applied to a Cornish or Lancashire boiler, Figure 2 being a plan of same.
Figure 3 is a front view of the furnace or grate and Figure 4 is an outside
elevation.
Figure 5 is a side elevation of the side frames of the grate illustrating more
particularly the artificial cooling arrangement; and Figures 6, 7, and 8 are cross
sections of same at the line A A, B B, and C C, respectively.
Figures 9, 10, 11 and 12 are details illustrating the bars and their means of
interconnection.
Referring to the drawings a is the furnace tube or flue of the steam generator,
and a' is the front plate thereof. 6 designate generally the side frames of the
furnace or grate upon or in connection with which practically the whole of the
parts are supported. 6¹ are extensions of the underside of 6, in the lower ends of
which the supporting and travelling wheels are mounted and run. 6³ are similar
projections or brackets to 61, in which a front supporting and travelling wheel 6* is
mounted and runs. c is the coal or fuel hopper of the grate. d is the fire brick
or refractory arch. e is the sliding regulating fuel feed door between the hopper c
and arch d. f is a wheel driven by a belt, or any suitable means, by which motion
is imparted to the grate bars, directly or indirectly. 9 are the front tooth or
sprocket rollers or wheels supporting, meshing with, and driving the grate bars;
and / is the back sprocket or toothed wheel for supporting the other end of the
bars. i are the grate bars or fuel bearers, and k are the links by which said bars
are connected together. I are the conduits or pipes through which the fluid for
keeping the frames 6 cool circulates. m are cross rods connecting the two side
frames 6 of the grate together. n are longitudinal bars supported by the cross
bars m and running from one end of the grate to the other. o are side bars on the

page_text: grate, covering and overlapping the edges or ends of the grate bars ;; said side
bars keep the fuel on the grate bars, and are bolted onto the top edge of the side
frames b. p is the bridge, and refractory brick work or material covering on
the top of same. is the hinged plate or device at the end of the grate by which
excess air is prevented from passing the end, and clinker and ash at the same time
allowed to be discharged. p is a step in connection with the bridge p up which
the roller bruns when the grate is run into the tube a. is a girder connecting
the ends of the frames together.
The grate bars i as shewn lie transversely to the length of the grate, and are
provided with projecting teeth or parts, on each side of the main tranverse
bar. Each bar is provided, also, at each end with two trunnions ³, and over these,
the links k, by which the bars are connected together, are fitted. When all the
bars are so connected up, they form an endless conveyor, running upon and over
the sprocket wheels g and at the front and back end, respectively; the wheel
(which is mounted upon a shaft g') being driven from the wheel f.
Each link kis kept in position on the trunnions by a pin and grooves ³ in
the trunnions, through which the pin passes. By this means, it will be obvious,
it is impossible that the links k can of themselves come off or become loose. The
slots or grooves in the trunnions are carried from the side, downwards, for over
a quarter of a circle: this is done to enable the trunnions to move about in the
links k, as for instance when they are passing over the pulleys g and h.
The ends of the grate bars, i are, also, provided with a strip or plate, which, in
the working of the grate, rest and slide on projecting supporting bars 68, formed
upon the inner sides of the frames b.
The sprocket wheel shaft g' is supported in movable bearings g², capable of
adjustment in the frames b, by the screwed pins 93 working in the bridge piece g
of the frame b. The shaft h' of the sprocket wheels h is mounted and revolves in
bearings in the back end of the side frames b.
Should the bars i as they are moving forward and supporting the fuel become
broken they will be caught and carried by the intermediate bars n, supported on
the cross rods m, and so be prevented from falling into and fouling the returning
bars below.
The portions of the side frames within the furnace flue or tube a are maintained
in a cool condition by water, or other fluids, passed or circulated through the tubes l,
which are cast in said side frames. One, the upper, of said tubes runs along and
is in contact with the upper part of the frame b, which is of angle section, and keeps
that part cool, whilst the other tube runs along and is in contact with the inwardly
projecting side bar 6, which carries or supports the fire bars i, and so keeps it, and
also the bars i, comparatively cool.
The portions of the side frames which lie within the tube a are preferably
formed separately, from those which lie without the tube, and are connected thereto
by bolts and nuts, or other means, at b.
The tubes are provided at the inlet or outlet end with cast or wrought bends,
having plugs 68 in their ends by which, upon their removal, the tubes could be
scraped and cleaned from these ends. At the opposite end, at the back of the
furnace, we provide equivalent connections adapted as a return coupling, each part
having a screw plug 68, as shewn, for the same purpose.
The water or other cooling fluid may be circulated through these conduits or
pipes by artificial or natural means. The cooling of parts of the grate in this
manner enables it to be entirely unconnected with the boiler or furnace, so that at
any time, for any purpose, the furnace or grate may be run upon its wheels bb
out of the furnace tube, and without any connections with the generator having to
be unfastened or broken.
The fire bars i are supported in returning from the back end of the furnace by
the inwardly projecting ledges or flanges on the ends of which the said bars i
rest and move.
The bridge p consists of a cast iron frame fitted or placed in the tube a, and

page_text: provided with a removable plate p³, which when removed, and the grate withdrawn
from the furnace, access is easily had to the back of the flue.
The device q consists of a plate running from side to side of the furnace with its
lower ends in contact with the surface of the fire bars i, or, with the ashes or
clinkers thereon which are discharged over the end of the grate, and a part q' at
right angles to the said plate, acting as a weight, and tending to retain the plate
against the fire bars. This device is preferably of cast iron and is provided at
each end with a projecting journal, which fits into and works in the inwardly
projecting bearings provided on the bridge casting p.
The action of the device, it will be seen, is that as ashes or clinkers are conveyed
forward by the travelling grate bars, and discharged over the end thereof, the
device 4 will be moved to and fro about its hinges, as the size and quantity of the
matter discharged varies; and at the same time prevents any large quantity or
excess of air to pass up above the fire bars and grate at the end of the furnace,
thereby rendering unequal or inefficient working and consumption of fuel, from
such a cause, impossible.
The fire brick or refactory arch d is supported at each side by a ledge d' cast or
fixed upon the inside of the frames b, whilst an arched bar or plate comes
between the front upper part of the arch, and the front plate of the steam
generator, the said plate or bar d² being secured by bolts or rivets onto the inside
of the side frames b. The sides of the arch d itself is supported laterally by the
frames themselves.
The fuel feed regulating sliding door e consists of a cast iron or other metal
frame, having within it a refractory of fire brick lining e¹, facing the interior of
the furnace. The door e is guided between inwardly projecting guide pieces e²,
formed on the inside of the side frames b, and a metal plate e provided on the
front face of the arch d, and suitably fastened at its sides to the side frames b.
The door is elevated and lowered by racks e, one being provided on each corner
of the frame thereof. The racks are formed in the shape of an inverted loop, the
teeth being formed on the outer pendant part thereof. This form and construction
is provided to enable the door to be withdrawn directly out of the frame and
replaced with facility. The up and down movement of the door is imparted to it
by the toothed wheels e fixed on the shaft e and meshing with said racks, the
shaft e being supported in bearings on the upper edges of the side frames b, and
worked by a ratchet wheel e thereon, and pawl and ratchet lever, from one side
of the grate. The door is retained in the position desired by a locking pawl to
which meshes, with one of the wheels e.
It will be seen that the back of the hopper, and the direction of inclination of
the door e and racks e', are parallel with each other; this admits of the door e
being completely removed or placed in position without having to remove any
parts..
The action and purpose of the door e is to regulate or control the quantity of
fuel fed to the furnace. The regulation is effected, and a larger or lesser quantity
of fuel fed to the fire bars, by the greater or less distance allowed between the
lower edge of the door and the level of the fire bars.
The back plate c' of the hopper is carried down to about the level of the bottom
of the arch d.
The front plate of the hopper is designated c², and is provided with journals c³,
which rest upon the open bearings on the extremities of the side projecting
ledges d', and is movable about its bearings cf. It is held and adjusted at its
upper edge by chains fixed to the frames 6, the links of the chain being adapted
to fit into notches in the upper edge of the plate. By this means the inclination
of the plates c can be varied, as may be deemed desirable or necessary in working.
The operation of feeding the fuel is effected as in other known forms of endless
conveyor grates (generally called "Jukes furnaces") by the forward motion of
the grate bars, which carry with them, as they pass the aperture of the hopper, the
portion of the fuel which is in contact with them, or directly above them, the depth

page_text: of fuel being regulated by the height of e above the surface of the grate bars. As
the fuel leaves the hopper and passes the door it is ignited by the heat of the
burning fuel in front of it, aided by the heat radiated from the refractory arch d,
combustion being supported by the air which passes through the grate bars; and by
the time the fuel on any part of the grate has reached the bridge, the combustion
of the fuel is completed, clinker and ash alone being discharged over the end.
To place the grate in position within the furnace, it is merely run in upon the
wheels and the front wheel running along the bottom of the furnace tube a,
and the two hind ones running on rails, plates, or the like upon the floor in front
of the furnace; and this operation of running it in or out may be effected without
making any connections or fixing with the steam generator, and without breaking
any.
We have illustrated our invention as applied to an internally fired steam generator,
namely one of the Cornish type, it is to be understood, however, that it may by
simple modifications he applied wholly, or in part, to various kinds of steam
generators, evaporating apparatus, and various furnaces or apparatus heated by the
combustion of solid fuels; although, at the same time, it is, when arranged as shewn
in the drawings, particularly applicable to internally fired steam generators, and
other apparatus having tubular furnaces or furnace flues, since it is capable of being
applied thereto without special fixings of any kind, and can moreover so readily be
inspected and repaired by its being capable of being removed in the manner
described which advantages, however, may obtain, in some cases also, when
applied in other purposes.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:
1. In a mechanical furnace or grate, conduits formed or provided in the side
frames or supports thereof, through which a cooling fluid is circulated, or may
circulate, whereby the frames are kept in a cool condition at the parts subjected to
great heat.
2. In a mechanical furnace or grate, the employment in connection with the back
or discharging end thereof, of a device, operating after the manner described, by
which entrance of air at the back end prevented, and without impediment to the
discharge of clinkers or ash or solids.
3. In a mechanical furnace or grate having transverse travelling fire bars,
connecting said bars together by trunnions formed thereon, and links, fitting on or
over said trunnions.
4. The combination with the trunnions (i) of transverse fire bars of a travelling
grate, of links, such as k, and a pin or pins in connection therewith and working or
disposed within a groove or grooves is said trunnion, for the purposes set forth.
5. In a grate or furnace having transverse travelling fire bars, the employment
of longitudinal bars under said fire bars between the side supporting frames of the
grate, whereby broken or dropping upper fire bars are prevented from fouling the
returning bars below.
6. A mechanical furnace having its parts constructed and arranged as set forth
with reference to and illustrated in the drawings.
Dated this 4th day of Auomet 1800
CHEESBROUGH & ROYSTON, Fels. Chart. Inst. P.A.,
15, Water Street, Liverpool, Applicants' Patent Agents.