Improvements in Fire-grates or Furnaces for the Combustion of Solid Fuel.
Year: 1891

page_text: Date of Application, 11th Sept.. 1591
Complete Specification Left, 24th May, 1892-Accepted, 25th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in Fire-grates or Furnaces for the Combustion of
Solid Fuel.
I, HENRY CHARLES PLATTS, of 4 Holland Park Terrace, Notting Hill, in the
County of London, Engineer, do hereby declare the nature of this invention to be
as follows:-
-
This invention has reference to improvements in fire grates or furnaces for the
combustion of solid fuel for steam generating, metallurgical, domestic and other
purposes and has for objects to enable the feeding and combustion of the fuel and
the admission of atmospheric air necessary for combustion to take place in a
convenient economical and advantageous manner, one of my principal objects
being to ensure that only sufficient air to support combustion efficiently shall be
allowed to enter the furnace, thus overcoming a serious drawback to which furnaces
as heretofore constructed have been liable.
For this purpose the fire grate or that part of the furnace in which the solid fuel
is held whilst being burnt, is constructed with outer and inner perforated or grid-
like walls arranged vertically, or at such an inclination that fuel fed to the space
between them from a hopper or hoppers at the top and sides will readily descend
by the action of gravity.
The perforated outer wall may be of refractory brick work, or of metal, and
through it atmospheric air or other supporter of combustion is admitted to the fuel.
This wall may be built into or otherwise secured to the sides of the apparatus and
be carried by a metal plate or support beneath which is an opening through which
clinker slag and ash may be withdrawn from the lower part of the fire grate, and
which opening is normally closed by a lid worked by a suitable handle.
The outer wall is provided with one or preferably with a series of external
adjustable air regulators cach consisting of a grating or perforated screen working
in suitable guides, for the purpose of regulating the admission of air to any part of
the fuel contained between the two walls and thus controlling the combustion of the
fuel to suit requirement.
The perforated inner wall is constructed of refractory material such as fire bricks
and through it the products of combustion and distillation pass into a combustion
chamber whence they pass to the object. to be heated or operated upon, and
eventually to a chimney or up-take. The combustion chamber is or may be
provided with one or more perforated partitions of refractory material such as fire
brick against which the gases mixed with atmospheric air passing through the inner
wall impinge for the purpose of thoroughly mixing the gases and atmospheric air
and effecting their complete combustion. The perforated partition or partitions
also serve as a reservoir of heat. Part of the combustion chamber may be carried
by a hinged plate, or be otherwise so constructed as to admit of ready access to the
interior of the combustion chamber. At or near the top of the fire grate is an air
passage through which air can flow when necessary to the fuel near the top of the
outer and inner perforated walls and be mixed with the gases in process of dis-
tillation for the purpose of effecting their complete combustion. This air passage
may conveniently be formed by arranging a metal plate opposite a non-perforated
portion at the top of the inner wall, the inlet to the air passage thus formed being
At the lower end of
guarded by a baffle plate to prevent entrance of fuel thereto.
the fire grate is a water trough that serves to cool the slag and ash formed during
combustion, to form steam to assist the process of combustion, and to cool the metal
ulate or support carrying the outer wall.

page_text: A fire place or furnace constructed as described may be placed in any convenient
position relatively to the steam generator or generators or other apparatus to be
heated, suitable ducts of refractory material being provided to conduct the flame
and heat to the desired place. It may also be placed either wholly or partially
within a steam generator or other apparatus or entirely outside of the same.
In the case of steam generators of the locomotive or portable engine type the
improved fire place or furnace may be placed either wholly or partially within the
fire box thereof.
In some cases part or all of the fire place or furnace is surrounded by a casting
of refractory material with fire brick or chequer work that will absorb the waste
heat radiated from the apparatus when the same is in use and act as an air
regenerator for heating the atmospheric air required for the combustion of the fuel.
This air after passing through the regenerator thus formed passes partly through
the outer wall, and partly through the air passage at the top of the fire grate to
the fuel. Means such as air regulating dampers are provided for regulating the
admission of air. The regenerator casing may be formed with a series of peep
holes through which the process of combustion may be observed and the fuel
stirred from time to time if necessary.
In the case of steam generators of the locomotive and portable engine type
where the fire grate or furnace is placed inside the fire box, as also in the case of
domestic fire-places, the air regenerator is dispensed with as the radiation is in
itself a means of heating the steam generator in the first case, and the apartment in
the second case.
Dated this 11th day of Sentember 1803
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Fire-grates or Furnaces for the Combustion of
Solid Fuel.
1, HENRY CHARLES PLATTS formerly of 4 Holland Park Terrace, Notting Hill,
but now of 22 Horbury Crescent, Notting Hill Gate in the County of London,
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 to improvements in fire grates or furnaces for the
combustion of solid fuel for steam generating, metallurgical, domestic and other
purposes, and has for objects to enable the feeding and combustion of the fuel
and the admission of atmospheric air necessary for combustion, to take place in
a convenient economical and advantageous manner, one of my principal objects
being to ensure that only sufficient air to support combustion efficiently shall be
allowed to enter the furnace, thus overcoming a serious drawback to which
furnaces as beretofore constructed have been liable.
For this purpose the fire grate, or that part of the furnace in which the
solid fuel is held whilst being burnt, is constructed with outer and inner
perforated or grid-like walls arranged vertically, or at such an inclination that
fuel fed to the space between them from a hopper or hoppers at the top and
sides will readily descend by the action of gravity.
The perforated outer wall may be of refractory brick work, or of metal, and
through it atmospheric air or other supporter of combustion is admitted to the
fuel. This wall may be built into or otherwise secured to the sides of the
apparatus and be carried by a metal plate or support beneath which is an opening
through which clinker slag and ash may be withdrawn from the lower part of

page_text: the fire grate, and which opening is normally closed by a lid worked by a
suitable handle.
The outer wall is provided with a series of external adjustable air regulators
each of which may consist of a grating or perforated screen arranged to work
in suitable guides or of a hinged or pivoted plate, for the purpose of regulating
at will, the admission of air to any desired part of the fuel contained between
the two walls, and thus controlling the combustion of the fuel to suit requirement.
The perforated inner wall is constructed of refractory material such as fire
bricks and through it the products of combustion and distillation pass into a
combustion chamber, whence they pass to the object to be heated or operated
upon, and eventually to a chimney or up-take. Part of the combustion chamber
may be carried by a hinged plate, or be otherwise so constructed as to admit
of ready access to the interior of the combustion chamber. At or near the top
of the fire grate is an air passage through which air can flow, when necessary,
to the fuel near the top of the outer and inner perforated walls, and be mixed
with the gases in process of distillation for the purpose of effecting their com-
plete combustion. This air passage may conveniently be formed by arranging
a metal plate opposite a non-perforated portion of the top of the inner wall,
the inlet to the air passage thus formed being guarded by a baffle plate to
prevent entrance of fuel thereto. At the lower end of the fire grate is a water
trough that serves to cool the slag and ash formed during combustion; to form
steam to assist the process of combustion; and to cool the metal plate or
support carrying the outer wall.
A fire place or furnace constructed as described may be placed in any convenient
position relatively to the steam generator or generators or other apparatus to be
heated, suitable ducts of refractory material being provided to conduct the flame
and heat to the desired place. It may also be placed either wholly or partially
within a steam generator or other apparatus or entirely outside of the same.
In the case of steam generators of the locomotive or portable engine type the
improved fire place or furnace may be placed either wholly or partially within the
fire box thereof.
In some cases part or all of the fire place or furnace is surrounded by a
casing of refractory material provided with fire brick or chequer work that will
absorb the waste heat radiated from the apparatus when the same
is in usc,
and act as an air regenerator for heating the atmospheric air required for the
combustion of the fuel. This air after passing through the regenerator thus
formed, passes partly through the outer wall, and partly through the air passage
at the top of the fire grate to the fuel. Means such as air regulating dampers
are provided for regulating the admission of air to the casing. The regenerator
casing may be formed with a series of peep holes through which the process of
combustion may be observed and the fiel stirred from time to time if necessary.
In the case of steam generators of the locomotive and portable engine type
where the fire grate or furnace is placed inside the fire box, as also in the case of
domestic fire-places, the air regenerator is dispensed with as the radiation is in
itself a means of heating the steam generator in the first case, and the apartment
in the second case.
In the accompanying drawings,
Fig. 1 is a vertical section through a fire grate or furnace according to this
invention;
Fig. 2 is a front elevation of the same; and
Fig. 3 is a horizontal section through one row of air inlets;
Fig. 4 is a vertical longitudinal section through a furnace according to this
invention, applied to a steam generator of the locomotive type;
Fig. 5 is a cross section on the line of Fig. 4.
Fig. 6 is a vertical longitudinal section through a furnace according to this
invention, applied to a steam generator of the Cornish type and provided with an
air regenerator casing;

page_text: Fig. 7 is a half section on the line y y of Fig. 6; and
Fig. 8 shows one half of the furnace in horizontal section and the other half in
plan.
In Figs. 1 to 3 the fuel is confined between an outer perforated wall 2, and an
inner wall 3 of the same description. The fuel is fed through a hopper 4,.furnished
with a lid 5, and it descends towards an ash pit 6, having an inclined back 7, which
throws the ashes and clinker towards the door 8 through which it is from time to
time removed. This ash pit may contain water for the purpose hereinbefore
mentioned. 8* is a handle for operating the door 8. The outer wall 2 is carried
on a metal plate 9, and is furnished on its face with a guide frame 10 in which
there slide perforated plates 11 which serve as air regulators. These plates are in
the example shown arranged in pairs one for each of the horizontal rows of air holes
in the outer wall 2. The plates are provided with handles 11" by which they can
be so arranged relatively to one another as to vary the sizes of the air admission
holes 11, or to completely close these holes if necessary, as shewn in Fig. 3. By
means of these regulators, the combustion at various parts of the fire place can be
independently and effectually controlled to suit varying requirements.
Air passing through the holes 11b and outer wall passes into and through the
fuel, supporting its combustion and its conversion into gas.
The gas passes
through the perforations in the inner wall, and into the combustion chamber 12,
whence the flames and heated products of the combustion are led to where they are
required. To facilitate complete combustion of the products of distillation from
the fuel there is an air inlet 13, formed in a plate 14, between which and the wall 3
there is a passage 14" for the circulation of air. This passage is in communication
with the external atmosphere and has its inner outlet end arranged at or near the
top of and between the perforated walls 2 and 3 and below the fuel charging
opening as shown. The air inlet 13 is protected from being choked by fuel by the
plate 15. Air descending the passage 14 mixes with the products of distillation
and effects their complete combustion.
The furnace shown in Figs. 4 and 5 is practically the same as that shown in
Figs. 1 to 3, with the slight modifications required to adapt it to be placed and
worked in the inside of the fire box of a locomotive boiler. As air cannot be
admitted directly to the perforations in the front wall 2, it is led through the ash
pit past a door 8 and thence upwards, it may be between heated fire bricks 16
arranged in front of the air regulators 11. These air regulators which are
arranged in pairs like those shown in Figs. 1, 2 and 3, though they may be arranged
singly, are controlled by rods 17 that extend through hollow stays 18 that pass
through the sides of the fire box as indicated in dotted lines in Fig. 5.
The ash pit 6 forms a part of a water trough 6" to contain water for the purpose
hereinbefore mentioned. The bottom 12 of the combustion chamber, is carried by
a hinged plate 12". This plate can be turned downward to allow the Bottom 12ª to
be removed to permit access to the combustion chamber; and it is fastened in its
closed position by a pin 12 which is passed through a lug 12" on the plate and
enters a fixed lug 12°.
In Eigs. 6, 7 and 8 a furnace according to this invention is shewn partly enclosed
within a brickwork casing 20 strengthened by iron plates 20 and filled with fire
bricks 21 arranged in the ordinary manner to present á large heating surface to air
flowing over and between them. 22, 22 are passages provided with sliding
dampers 23 for controlling the admission of air to the casing 20. The door 8 also
serves to admit air direct to the space in front of the outer wall 2 when necessary.
In this arrangement the air supplied to the passage 14" will be mainly hot air
supplied from the interior upper portion of the casing 20 as indicated by the arrow.
The front of the casing is formed with peep holes 24 normally closed by plugs 25.
The inner perforated wall 3 may be formed with a number of lateral passages 3 as
shewn in Figs. 6 and 8 with a view of effecting an intimate mingling of the air and
products of incomplete combustion passing through this wall. Hoppers 4 and 4"
at the sides and top respectively of the fire place serve to feed fuel to inclined

page_text: and 3.
passages 4 the lower or outlet ends 4ª of which are below the tops of the walls 2
With this arrangement should cavities be formed in the fuel introduced
into the space between the walls 2 and 3 from the top hopper 4, they can be readily
filled by introducing fuel through one or more of the inclined passages 4° thus
ensuring the regular working of the furnace. The fire-grate is, shewn applied to
heat a Cornish boiler 26, but it may obviously be applied to heat any other required
object. For instance the combustion chamber 12 may be placed in direct com
munication with the heating chamber of a melting, reducing, or other furnace.
Although I prefer to arrange the air regulators 11 in pairs as shown and
described, so that should one of them become damaged it can be removed and
repaired whilst the other remains effective to control the supply of air, it will be
obvious that the said air regulators can be arranged singly. In this case they may
be arranged to slide as hereinbefore described, or they may be hinged or pivoted,
suitable handles being in each case provided for controlling them from the exterior
of the furnace.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1. A fire place or furnace constructed with two perforated or grid-like walls
such as 2 and 3 of refractory material arranged to form between them a fuel space
closed at the sides and bottom and through which solid fuel can descend by gravity
from above, the perforations in one of said walls serving for the inlet of air, and the
perforations in the other of said walls serving for the exit of products of combustion
and distillation, and with air regulators arranged in front of one of the said walls in
such a manner that the supply of air to different parts of the fuel space can be
varied at will to suit requirement substantially as described and shown.
2. A fire place or furnace of the kind referred to in the preceding claim,
constructed with an air inlet passage such as 14ª having its outlet end arranged at
or near the top of and between the perforated walls forming the fuel space and
below the fuel feeding opening substantially as described and shown for the purpose
specified.
3. A fire place or furnace of the kind referred to in Claim 1, arranged to be
surrounded or partly surrounded by a casing of refractory material containing fire
bricks or chequer work, that will absorb heat radiated from the fire place or furnace
and impart such heat to air flowing through the casing on its way to the fire place
or furnace substantially as described and shown.
4. A fire place or furnace of the kind referred to in Claim 1, constructed with
hoppers at the front and sides the lower ends of which communicate with fuel
charging passages having their lower ends terminating in the fuel space at a point
below the top of the perforated or grid-like walls substantially as described and
shown for the purpose specified.
5. My improved fire grates or furnaces for the combustion of solid fuel, con-
structed, arranged, and operating substantially as hereinbefore described with
reference respectively to and shown in Figs. 1, 2, 3; in Figs. 4, and 5; and in
Figs. 6, 7 and 8 of the drawings annexed.
1000
HENRY CHARLES PLATTS.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.