IMPROVEMENTS IN FURNACES AND MECHANICAL PROVISIONAL SPECIFICATION
Year: 1882

page_text: LETTERS PATENT to John Cresswell Brentnall of Timperley, in the County of
Chester, for an Invention of "IMPROVEMENTS IN FURNACES AND MECHANICAL
PROVISIONAL SPECIFICATION left by the said John Cresswell Brentnall.
at the Office of the Commissioners of Patents on the 4th December 1882.
JOHN CRESSWELL BRENTNALL of Timperly in the County of Chester "Improve-
MENTS IN FURNACES AND MECHANICAL STOKERS AND IN ARRANGEMENTS AND
PARTS CONNECTED THEREWITH."
My invention relates to and consists of a combination and arrangements of parts
or mechanism for the feeding and combustion of coal or other fuel for generating
steam and other heating purposes, and its object is to reduce labour, diminish or
prevent smoke and economise fuel.
The coal is filled into a hopper and this hopper is or may be arranged and divided
to supply fuel to one or more furnaces, the hopper conveys the fuel to a box below
it in which there is a horizontal shaft carrying a toothed roller which rotates with
the shaft.
In the box below the hopper there is also another horizontal shaft having an
excentric upon it for each of a series of separate curved bars placed side by side,
the surfaces of which bars are toothed.
Each excentric gives up and down, and to and fro movement to the upper end
of each curved bar, one excentric is or may be set to give movement to its bar at a
different time to the others.
The lower ends of the curved toothed bars slide against a fixed, but adjustable
rod, or in place of a rod, an excentric shaft is or may be used, so that by either the
rod or excentric shaft, the ends of the curved toothed bars can be brought nearer to
or further from the toothed roller.
The fuel passes from the hopper between the rotating toothed roller and the
curved toothed bars, and is thus crushed to the required extent, and fed downwards
at the same time.

page_text: The fuel passes from the box through a hole in a plate below the box into a
combustion chamber, and falls upon the furnace bars near their outer ends.
The combustion chamber has its top and sides formed of iron protected by fire
bricks or slabs, or blocks of fire brick material.
The front of the combustion chamber has an opening through which coal
can be supplied by hand stoking, and the fuel may be stirred or withdrawn when
desired.
This opening is closed by a barred frame or grid or a perforated door, and this
frame or grid is enclosed by another door.
There is also a door hinged to the bottom of the door or cover which can be
opened or closed; when open more or less air is admitted as desired, to pass through
the grid frame or perforated door to the fuel in the combustion chamber.
The furnace bars are compound each formed of a lower or bearing bar, and an
upper bar made by preference in short lengths or sections-The lower or bearing
bar is formed by two side bars lengthway with a space between them connected by
short cross bars, and the sections of the upper bar are made with hooks that pass
between and hook upon the cross bars of the lower bearing bar, the end section of
the upper bar being secured by a screw, pin, cottar, or other means, and thus secures
all the other sections of the upper bar upon the lower bearing bar.
There is a space between the upper bar or sections and the lower bearer for air,
the former only resting upon the latter at intervals.
These compound furnaces rest and slide upon a stationary cross bearer passing
between the sides of the furnace at the inner ends, and at the outer end, each bar
is made to fit and be actuated by three excentrics or cams one of which is placed
between the other two and gives the end movement to the bar, the other two
excentrics or cams act to give lifting movement to the bar, and as these excentrics
are or may be made of different "throw" the to and fro is or may be made
greater than the lifting movement, and this may be varied as desired.
There is a separate set of excentrics or cams for each furnace bar all placed upon
the same shaft, but the excentrics or cams for adjoining furnace bars are set to act
alternately, and the movement given to the furnace bars acts to propel the fuel
along them from the combustion chamber, at such speed that when it arrives at the
inner ends of the bars the combustible part of the fuel is exhausted and the ashes
drop from the ends of the furnace bars to the ash place below, and between the
ends of the furnace bars and the fire bridge.
The rotating shafts hereinbefore mentioned are geared together by shafts and
worm and worm wheels or in any other convenient manner, the first motion shaft
being driven by a belt or otherwise from any convenient motor.
In passing from the combustion chamber the fuel goes under an inverted bridge
or archway formed of fire brick or other suitable material and the space between
this bridge and the surface of the fire bars regulates the thickness of the fuel upon
the latter, within the furnaces, and as such fuel after passing the inverted bridge,
has become incandescent, it assists in consuming any gases that may pass from the
combustion chamber.
In some cases my invention consists in using one hopper to supply fuel to two
combustion chambers in which case there is a passage from the hopper in the centre
to the hole at the upper side of the two combustion chambers, and in this passage
between the two holes there are two rams one of which can slide on the bottom of
the passage and the other ram slide upon the latter.
The slides or rams have movement given to them in the lengthway of the
passage but in opposite directions by excentrics or levers or any other convenient
mechanism.
At the tops of and across the combustion chambers and at one side of the same
a horizontal bar is arranged carrying an arm which extends nearly across the upper
part of the combustion chamber from the front to the back; this horizontal bar is
moved to and fro endways by a lever, which is formed in two parts jointed together,
and one part of this lever has two arms to which chains or rods are attached,

page_text: which are at their other ends attached to a weight or spring that will give sufficient
force to keep the two parts of the lever rigid, when working under normal
conditions, but when there is too much coal fed and there is an obstruction, the
weight or spring gives way and the chains or rods act upon a clutch or other
arrangement to stop the rotation of the mechanisin giving motion to the feeding
mechanism until the obstructing coal has passed away, when the spring or weight
acts again to bring the clutch or other arrangement, and thus the feeding mechanism
into gear again.
By another modification of my invention the combustion chamber instead of
being outside is arranged inside the flue or fire box of the furnace and either of
the arrangements bereinbefore described are used and adapted for supplying the
fuel to the combustion chamber.
The inverted bridge or archway hereinbefore referred to is formed either of fire
brick or similar material as hereinbefore mentioned or is a chamber formed of
metal connected with the water space of the boiler when the furnace is applied to
boilers.
When my invention is used in furnaces for "puddling" iron or similar purposes
where it is necessary at times to supply fuel to the furnace for the purpose of
generating gas to prevent the oxidation of the metal. I arrange a separate hopper
or form a shoot from the hopper feeding to the combustion chamber, so that when
desired the furnace man by drawing a damper, may allow á quantity of fuel to
pass on the inside of the inverted bridge to fall upon the incandescent fuel on the
bars, and thus generate the desired gases.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Cresswell Brentnall in the Great Seal Patent Office on
the 2nd June 1883.
JOHN CRESSWALL [sic] BRENTNALL of Timperley in the County of Chester,
"IMPROVEMENTS IN FURNACES AND MECHANICAL STOKERS AND IN ARRANGEMENTS
AND PARTS CONNECTED THEREWITH.”
My invention relates to and consists of a combination and arrangement of parts
or mechanism for the feeding and combustion of coal or other fuel for generating
steam and other heating purposes and its object is to reduce labour, diminish or
prevent smoke and economise fuel.
The coal is filled into a hopper and this hopper is or may be arranged and divided
to supply fuel to one or more furnaces, the hopper conveys the fuel to a box below
it in which there is a horizontal shaft carrying a toothed roller or a series of toothed
wheels which rotate with the shaft.
In the box below the hopper there is also another horizontal shaft having an
excentric upon it for each of a series of separate curved bars placed side by side
the surfaces of which bars are toothed.
Each excentric gives up and down, and to and fro movement to the upper end of
each curved bar, one excentric is or may be set to give movement to its bar at a
different time to the others.
The lower ends of the curved toothed bars slide against a fixed or adjustable rod,
or in place of a rod, an excentric shaft is or may be used, so that by either the rod
or excentric shaft, the ends of the curved toothed bars can be brought nearer to or
further from the toothed roller.
The fuel passes from the hopper between the rotating toothed roller and the
curved toothed bars, and is thus crushed to the required extent, and fed downwards
at the same time.
The fuel passes from the box through a hole in a plate below the box into a
combustion chamber and falls upon the furnace bars near their outer ends.
The combustion chamber has its top and sides forined of iron protected by fire
bricks or slabs, or blocks of fire brick material.
The front of the combustion chamber has an opening through which coal can
be supplied by hand stoking and the fuel may be stirred or withdrawn when
desired.
This opening is closed by a barred frame or grid or a perforated door and this
frame or grid is enclosed by another door.
There is also a door hinged to the bottom of the door or cover which can be
opened or closed, when open more or less air is admitted as desired, to pass through
the grid frame or perforated door to the fuel in the combustion chamber.
Air is also admitted at the upper part of the combustion chamber in or between
the two parts of the bridge or arch therein.
The furnace bars are compound each formed of a lower or bearing bar, and an
upper bar made by preference in short lengths or sections.
The lower or bearing bar is formed by two side bars lengthway with a space
between them connected by short cross bars, and the sections of the upper bar are
made with hooks that pass between and hook upon the cross bars, of the lower
bearing bar, the end section of the upper bar being secured by a screw, piu, cottar
or other means and thus secures all the other sections of the upper bar upon the
lower bearing bar,

page_text: There is a space between the upper bar or sections and the lower bearer for air,
the former only resting upon the latter at intervals.
These compound furnace bars rest and slide upon a stationary cross bearer
passing between the sides of the furnace at the inner ends; and at the outer end,
each bar is made to fit and be actuated by three excentrics or cams one of which is
placed between the other two and gives the end movement to the bar the other
two excentrics or cams act to give lifting movement to the bar, and as these
excentrics are or may be made of different "throw" the to and fro is or may be
made greater than the lifting movement and this may be varied as desired.
There is a separate set of excentrics or cams for each furnace bar all placed upon
the same shaft but the excentrics or cams for adjoining furnace bars are set to act
alternately and the movement given to the furnace bars acts to propel the fuel
along them from the combustion chamber at such speed that when it arrives at the
inner ends of the bars the combustible part of the fuel is exhausted and the ashes
drop from the ends of the furnace bars to the ash place below and between the ends
of the furnace bars and the fire bridge.
The rotating shafts hereinbefore mentioned are geared together by shafts and
worm and worm wheels, or in any other convenient manner, the first motion shaft
being driven by a belt or otherwise from any convenient motor.
In passing from the combustion chamber the fuel goes under a bridge or archway
formed of fire brick or other suitable material, and the space between this bridge
and the surface of the fire bars regulates the thickness of the fuel upon the latter
within the furnace and as such fuel after passing the inverted bridge has become
incandescent it assists in consuming any gases that may pass from the combustion
chamber.
In some cases my invention consists in using one hopper to supply fuel to two
combustion chambers in which case there is a passage from the hopper in the centre
to the hole at the upper side of the two combustion chambers, and in this passage
between the two holes there are two rams one of which can slide on the bottom of
the passage and the other ram slide upon the latter.
The slides or rams have movement given to them in the lengthway of the
passage but in opposite directions by excentrics or levers or any other convenient
mechanism.
By another modification of my invention the combustion chamber instead of
being outside is arranged inside the flue or firebox of the furnace, and either of the
arrangements herein before described are used and adapted for supplying the fuel to
the combustion chamber.
The bridge or archway herein before referred to is formed either of fire brick or
similar material as hereinbefore mentioned or is a chamber formed of metal,
connected with the water space of the boiler when the furnace is applied to
boilers.
When my invention is used in furnaces for puddling iron or similar purposes
where it is necessary at times to supply fuel to the furnace for the purpose of
generating gas to prevent the oxidation of the metal-I arrange a separate hopper
or form a shoot from the hopper feeding to the combustion chamber so that when
desired the furnace man by drawing a damper may allow a quantity of fuel to pass
on the inside of the bridge to fall upon the incandescent fuel on the bars, and thus
generate the desired gases.
Fig 1 is an elevation of the furnace end of a double flued boiler and shows by
one half an outside elevation or front view of one modification according to my
invention and by the other half a sectional elevation through the front chamber
and hopper of the same modification of my invention.
Fig 2 is a side elevation of the modification illustrated by fig 1.
Figs 3 and 4 are respectively a detached side and edge view of one of the toothed
wheels used in the hopper for reducing and feeding the coal.
Fig 5 is a side, and tig 6 an edge view of one of the curved toothed bars used in
the hopper. to assist in reducing and feeding the coal,

page_text: t
Fig 7 is an edge view similar to fig 6 but showing one of the wider curved bars
used at two sides of the hopper feeding chamber.
Figs 8, 9 and 10 are respectively side, end and plan or top edge views of part of
one of the bearing bars of the compound fire bars.
Figs 11 and 12 are respectively side and plan or edge views of one of the
lengths or sections that are carried on the upper edge of the bearing bars shown by
figs 8, 9 and 10.
Figs 13 and 14 are respectively side and edge views of the excentrics or compound
excentrics for giving movement to the fire bars.
Fig 15 is an end elevation showing an end view on one half and a sectional
view of the hopper and combustion chamber, illustrating another modification of
my invention.
Fig 16, is a longitudinal section of the modification shown by fig 15.
Fig 17 is a front elevation, and fig 18 a longitudinal section illustrating another
modification of my invention and Fig 19 is a plan sectional view of parts of the
fire bars and front of the furnace common to all modifications of my invention
herein before referred to.
In figs 1 and 2 a is the end of a double flued steam boiler; b is a casing carried
on feet b¹ and fitting to the front of the two flues. This casing 6 is lined with fire
bricks or slabs b'.
A double hopper c is mounted upon and secured to the casing b with a compart-
ment for each furnace opening from the hopper opposite & hole b³ in the top of
casing b.
These compartments contain the mechanism for reducing and feeding the coal
which mechanism consists of a series of toothed wheels d (see figs 3 and 4) each
having a square hole, by preference, in its axis, to be passed on to a corresponding
shaft or axis d', which has suitable bearings in the sides of the compartments of
the hoppers, and in a stand 6' on the casing b. This shaft d' receives rotary motion
from a worm wheel d² loose on the shaft, the boss of which has bearings in the
stand 6* for the shaft d' and the boss has clutch teeth in its face to correspond with
a clutch boss d³, made to slide on the shaft d' being connected therewith by a key
and key groove-The movable half of the clutch is actuated to put it in and
out of gear by a clutch lever handle centred at d³ on a bracket secured to the
casing b.
The curved toothed bars de (see figs 5, 6 and 7) are upon a shaft d' which passes
through the hole d* in the end of each bar do, and this shaft is or may be one
excentric, or made up of a separate small excentric for each bar keyed or otherwise
Diade to rotate with the shaft d' and acting at different times to give a to and fro
and up and down movement to the curved bars do, the lower ends of which slide
upon a bar d passing across the chamber.
The rotating shaft d for the curved bars do has or may have rotary motion
given to it by spur wheels from the shaft d'.
e is the bridge in and between the combustion chamber and furnace.
It is by preference formed with one part e of the arch lower than the other
part ex of the arch, leaving a slit or space el at the upper part between the two
parts of the arch e and e' to admit air, which slit has or may have a lid or door to
regulate or shut off the admission of air.
This air space e' at the position shown is an important means of preventing
smoke, both when the fuel is fed by the hopper mechanism selfacting and by
ordinary hand firing.
The fuel fed from the hopper c drops on to the front parts of the fire bars but
does not ignite until it comes about under the lower part of the arch e of the
combustion chamber.
The fire bars are formed as illustrated by figs 8, 9 and 10 that is each bearer
has two side bars f connected by cross bars f¹ the surface of the fire bars being
formed by short lengths or sections f' as shown by figs 11 and 12.
The underside of each section fi rests upon the projections ƒ³ on the sides

page_text: of the bearers f and there are two descending projections f* from each length
of surface bar f having hooks which hook upon the cross bars f¹.
The inner ends of the fire bar bearers f rest and slide upon a cross bar or
bearer extending across the furnace under the fire bars and the outer ends of
the fire bars each rest upon a compound excentric, each excentric being side
by side on a shaft g' passing in suitable bearings in front of the furnace.
These excentrics have each a key or keys, to fit a key groove or grooves on the
shaft and each excentric is arranged to give alternate movements in reference to
the immediately adjoining bars.
The end of each fire bar bearer f is formed to receive end movement from the
middle excentric g and a less vertical or up and down movement from the smaller
excentrics gx one on each side, which are practically one excentric, as they give
precisely the same simultaneous movements.
The shaft glis rotated by a similar arrangement of worm wheel and clutches,
with a lever clutch handle for bringing the clutch in and out of gear, as that
herein before described in reference to the shaft d¹ for reducing and feeding the fuel
from the hoppers.
The worm wheels on the shafts & and g' are geared with worms g² on a diagonal.
shaft ga in suitable bearings which has a worm wheel g' in gear with a worm on
the boss of a belt pulley g rotating on a stud secured in the framing this belt
pulley being the fast pulley of the fast and loose pulleys for the driving belt driven
from the motor employed.
The fuel does not drop directly from the hopper to the fire bars, but against
angular deflecting bars h³ secured across the inner grid door these deflecting bars
having spaces for air to pass between them.
The furnace door is double the inner grid or perforated door h and outer door h
both hinged on the same pivot or axis ha and the outer door h² can be opened and
then the inner grid door h or both outer and inner door is or may be opened at
the same time.
The outer door h² shuts off the air to the inner grid or perforated door h except
what may be allowed to pass through a rotating or sliding grid valve in the outer
door h² which is not shown in the drawings. Figs 15 and 16 illustrate that
modification of my invention where one hopper c supplies fuel to a compartment c*
supplying two furnaces.
On the upper side of the casing 6 of the combustion chamber there is a sliding
ram k that extends across the compartment cx and there is another shorter ram k¹
sliding upon the upper side of the lower ram k.
These rams have each a to and fro motion imparted to them by rods forked to
extend on each side of the exterior of the compartment cx and these forks are
connected by set screws or bolts passing through the ends of the forks and slots in
the sides of the compartment c* into the rams.
The forked rod 2 for the lower ram is jointed with one arm of a bell crank
lever having its fulcrum k on a bracket secured to the casing b and this lever k³
receives oscillations from a rod jointed to it which is or may be actuated by
a rotating excentric arranged and driven in any convenient manner.-The end
of the excentric rod can be changed nearer to or further from the fulcrum
of the lever k to give more or less movement to the rams as may be required.
The forked rod for the upper ram is also jointed to a bell crank lever k²
having its fulcrum 8 on the same bracket, and one arm of this bell crank lever is
connected to the arm of the other bell crank lever by a rod so that simultaneous
movements in opposite directions are imparted to both rams kand and these
movements alternately push and feed the fuel to the opening b³ from which it
drops to the combustion chambers.
The opening e' to admit air into the combustion chamber hereinbefore referred to
is more clearly shown in fig 16.
The deflectors h' attached to the inner grid door h are also clearly shown in
section in fig 16.

page_text: The other parts of the furnace in the, modification shown by figs 15 and 16 are
similar to those herein before described.
Figs 17 and 18 illustrate a modification where the combustion chamber is formed
within the flue.
The hopper c and fuel feeding arrangements are similar to those shown by
figs 15 and 16 except that the passage from the ram compartment c* of the
hopper to each furnace is curved or inclined to convey the fuel inwards as shown
in fig 18.
The parts corresponding to the bridge are formed by two hollow tubes e and ex
extending across the furnace and being. steam tight and communicating with the
water space of the boiler.
-
There is a space for air at e¹ between the feeding part cx of the hopper and the
end of the boiler to conduct the entering air over the outer tube e to escape into
the combustion chamber at the space between the hollow tubes or arches.
In this modification the bottom ram k is of V shape on its underside as shown,
there is a double fire door h and has hereinbefore explained and deflectors are
or may be secured to the inner grid door if required.
In place of hollow water filled tubes e and ex arches or slabs of fire brick
or other suitable material may be used arranged with the air space el as herein-
before explained.
I have now particularly described the nature of my said invention and the
modes of carrying the same into effect and claim as my invention.
Firstly. The combination and arrangement of furnace mechanism substantially
as hereinbefore described and illustrated by figs 1 to 13 inclusive and fig 19 of the
drawings.
Secondly. The arrangement of the curved toothed bars combined with the
toothed wheels for reducing and feeding the fuel as hereinbefore described and
illustrated by the drawings.
Thirdly. The construction of fire bars whether stationary or moving as herein.
before described and illustrated by figs 8, 9, 10, 11 and 12 of the drawings.
Fourthly. The use of a compound excentric for actuating movable fire bars as
hereinbefore described and illustrated by the drawings.
Fifthly. The combination with a hopper of two double acting rams one upon the
other to feed fuel to furnaces substantially as hereinbefore described and illustrated
by figs 15 to 18 inclusive of the drawings.
Sixthly. The combination and arrangement of furnaces and fuel feeding arrange-
ments substantially as hereinbefore described and illustrated by figs 15 to 18
inclusive of the drawings.
Seventhly. The combination with a combustion chamber having an arch or
bridge descending from the upper part of the chamber of a space in or between
the upper part of the arch or bridge, or its equivalent, to admit air to the com-
bustion chamber substantially as hereinbefore described and illustrated by the
drawings.
Eighthly. The combination with my improved furnaces and mechanical stokers
when applied to puddling furnaces of an arrangement for giving a temporary
supply of fuel to the furnace beyond the arch or bridge of the combustion chamber
substantially as and for the purpose hereinbefore described.
In Witness whereof I the said John Cresswall [sic] Brentnall have hereunto
set my band and seal this first day of June in the year of our Lord
one thousand eight hundred and eighty three.