CERTAIN IMPROVEMENTS UPON FIRE GRATES AND THE MEANS OF INTRODUCING COAL THEREON
Year: 1822

page_text: TO ALL TO
HESE PRESENTS SHALL COME, 1,
VILLIAN
BRUNTON, of Birmingham, in the County Warwick, Engineer, send greeting.
WHEREAS His most Excellent Majesty King George the Fourth did, by
His Letters Patent under the Great Seal of that part of the United Kingdom
of Great Britain and Ireland called England, bearing date at Westminster,
the Twenty-sixth day of June, 1822, in the third year of His reign, give and
grant unto me, the said William Brunton, my exors, aditiors, and assigns,
His especial licence, full power, sole privilege and authority, that I, the said
William Brunton, my exors, adñiors, and assigns, during the term of years
therein mentioned, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick upon Tweed, my Invention of
"CERTAIN IMPROVEMENTS UPON FIRE GRATES AND THE MEANS OF INTRODUCING COAL
THEREON;" in which said Letters Patent there is contained a proviso that if I,
the said William Brunton, shall not particularly describe and ascertain the
nature of my said Invention, and in what manner the same is to be performed,
by an instrument in writing under my hand and seal, and cause the same
to be inrolled in His Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the said Letters Patent, that
then the said Letters Patent, and all liberties and advantages whatsoever thereby
granted, shall utterly cease, determine, and become void, as in and by the same
(relation being thereunto had), will mere fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
William Brunton, do hereby declare that the nature of my said Invention, and
the manner in which the same is to be performed, are particularly described
and ascertained in the following description thereof, (that is to say) :-
My said improvements consist in conveying the fire progressively through
the furnace by the motion of the grate bars, and by the same means depositing
the clinkers or other incombustible matter into a receptacle at the further end
of the furnace, and I intend that grates constructed after this manner shall be
designated and known by the appellation of peristaltic grates; secondly, in
introducing the coal upon the fire and regulating the same by means herein-
after described. In describing my said improvements on fire grates I shall for
the sake of perspicuity divide the length of the furnace, of which my said
improved grate is the floor, into three distinct parts; first, that next to the fire
door or front of the furnace, which I call the close or dead part, upon
which the coals is introduced; secondly, the open or fire part, upon which the
combustion of the fire is carried on; thirdly, the exit part, upon which are
conveyed the clinkers and other incombustible inatter into a close receptacle
inclosed at the farther end of the ash-pit, over which the exit end of the grate
bars are made to project at the bottom of the said receptacle there is an iron
door closely fitted, by which it is occasionally emptied. I also make the front
of the bridge wall of the furnace to project about two or three inches over the
exit ends of the bars, and about three inches above, thus leaving an opening
for the discharge of the clinkers and other incombustible matter. The above
three parts I construct upon one length of bars, which I shall designate in the
following Specification grate bars, or for brevity, the bars. The portion of the
grate bars which form the floor of the close part of the furnace I make from
eighteen to twenty-four inches long, with parallel and flat sides, so as to leave
the least practicable interstice between them consistent with their being indi-
vidually loose and moveable. The portion of the grate bar which forms the
opening or fire part of the furnace I form similar to the grate bar in common
use, leaving an interstice between the bars of sufficient width for the adinission
of air as well as the discharge of dust, the length varying with the required
efficiency of the furnace. The third or exit portion of the bars I make from
nine to twelve inches long, making the sides parallel and flat, leaving as little
space betwixt the bars as is practicable. In moving the fire progressively
through the furnace, first, I cause each alternate grate bar to rise simul-
taneously above the common or mean surface of the grate bars, and while thus
raised and bearing the chief weight of the fire, to move onward in the direction
I intend the fire to be conveyed, and when they have arrived at the end of

page_text: their range to fall below the other bars or the said mean surface of them, and
while thus depressed to move in a contrary direction toward the other extremity
of their range, preparatory to a repetition of their action. But to be more
perspicuous, I will suppose the grate bars to be numbered 1, 2, 3, 4, 5, 6, 7, 8,
9, 10, and so forth. I fix, as in the usual manner, the bars No 1, 3, 5, 7, 9,
and so forth, and to the bars 2, 4, 6, 8, 10, and so forth, I communicate the
motion as above described; or, secondly, I cause each series of alternate bars
to move simultaneously in the manner already described. Thus I cause the bars
No 1, 3, 5, 7, 9, and so forth, to rise above the common surface, and to move
onward, whilst the other series, namely, N° 2, 4, 6, 8, 10, and so forth, fall and
move in the contrary direction, each series thus maintaining a reciprocal action
on the fire. Thirdly, I also produce the same progressive movement of the
fire by inclining the grate bars about one in seven lower toward, the end to
which I wish to convey the fire, and then communicate to each bar, or to
each alternate bar, a reciprocating motion either in the direction of its own
length or in the direction of a right angle to the surface of the grate, or of any
intermediate angle between the surface of the grate and the perpendicular
thereto on the side toward the lower end of the grate bars. Fourthly, I also
produce the progressive movement of the fire by a combination of the motions
already described, and cause the upper end of the bars (being laid sloping as in
the third case) to partake of the motion, as described in the first and second
cases, namely, alternately to rise above the common surface and move onward
with the fire, whilst the other end of the said bars lie upon and slide with a
reciprocating motion in the direction of their own length over a fixed bearer.
Having specified the motions which I communicate to the grate bars in order
to obtain a progressive movement of the fire, I shall now describe the means
by which I produce the several motions, which means I generally use and
recommend, but wish to be understood as not confining myself exclusively to
them. To produce the first motion I construct two or more bearers extending
the whole length of the grate, moveable round their own axis, which I call
eccentric or revolving bearers, or for brevity, bearers, having at proper
intervals, suited to the thickness of and width between each alternate grate bar,
circular bearers having from half an inch to one inch eccentricity with the axis
of the bearer; these bearers I connect by wheels, namely, a wheel of equal
diameter on each bearer, and an intermediate wheel between, so that the said
eccentric bearers revolve in the same direction and in the same time, and
having the eccentric circular bearings for the grate bars in the same position.
The said bearers have gudgeons extending from their ends, and are thereby
supported upon the side walls of the ash-pit under the open or fire part of the

page_text: grate bars, and each alternate moveable bar having proper projections, with
curved feet, suited to their respective eccentric circular bearings, rest thereon.
The eccentric bearers being turned round by the power of a steam engine, or
any other convenient power, will communicate to the moveable alternate bars
the required motion, that is, by the eccentricity of the circular bearings the bars
resting thereon will be raised above the fixed bars, move onward in the direction
in which the eccentric bearers are turned, at the end of their range fall below
the fixed bars, upon which they deposit the fire, and while depressed return
to repeat their action upon the fire. I produce the second motion by con-
structing two or more eccentric or revolving bearers, suited to the width of the
grate and similar to those used in producing the first motion, but having at
proper intervals, suited to the thickness of and width between each grate bar,
circular bearings having from one quarter to three quarters of an inch eccen-
tricity with the axes of the bearer, these bearing having their eccentricity
alternately on opposite sides of the centre of the bearer; the said revolving
bearers I connect by wheels, revolve in the same direction and time, and the
eccentric bearings disposed in the same order as already described for those of
the first motion, and the grate bars resting upon their respective bearings; the
said revolving bearers being turned round in the direction in which it is intended
to move the fire, one series of alternate bars will rise up and support the fire
and move onward, whilst the other series depressed will move in the contrary
direction. In producing the several modifications of the third motion I con-
struct one or more revolving bearers, similar to those already described as
suitable to the second motion, but the grate bars, instead of resting wholly
upon the revolving or eccentric bearers, are made to rest or slide, partly or
altogether, upon fixed bearers. The surface upon which the bars slide or
move, and also the face of those parts of the bar which rest or slide
thereon, I make in the same direction in which it is intended the bar
should be moved, and also the bars do not rest upon the revolving bearer with
curved feet, (as in the first and second motion,) but are connected therewith
by two straight parallel checks attached to or cast with the said bars, at such
distance from each other as is equal to the dianicter of the circular eccentric
bearings of the revolving bearer, and the said parallel cheeks are attached to
the bar at such an angle or position as will suit the movement intended to be
given, that is, they are placed at right angles to the intended line of motion
and so long as to permit the eccentric bearings to revolve between then
without communicating any other motion than that at right angles to the said
cheeks; thus, if the motion is intended to be in the direction of the length o
the bars, the surface of the fixed bearer, and also that of the part of the ba

page_text: resting or sliding thereon will be paralel to the surface of the grate, and the
checks cast upon the bar will stand at right angles to it. In producing the
fourth motion, I construct one eccentric or revolving bearer as suitable to the
second or third motions, and I also construct each of the grate bars with a
curved foot toward their upper end, suited to and resting upon the eccentric
bearings of the revolving bearer, whilst the lower ends of the said grate bars
rest upon a fixed bearer, over which they slide as the revolving bearer is turned
round, and communicates to the higher end of the bars that motion (simular to
the second,) by which the fire is progressively moved toward the lower end of
the grate. To prevent the admission of air below the bars whilst they are moved
above and below the common surface of the grate upon the under edge of those
bars which are thus lifted, and upon the dead or close part and exit part of the
bar, I cast a tooth as wide as the parts of the bar to which they are attached,
and about two inches in the other direction, and about six inches long, which
projects downwards into a trough extending from side to side of the grate, and
is filled with sand or water, in which the said teeth are immersed, and work
sufficiently deep to prevent the air passing under them when the bars are
elevated; when the said tooth is used at the exit end of the grate the said sand
or water trough rests upon the wall which forms the end of the open ash-pit,
and incloses the receptacle for the clinkers and scoria, and when the said tooth
is used at the dead end of the grate, the said sand or water trough is carried
by the side walls of the ash-pit and the space between it and the front of the
furnace is inclosed either by an arch of brick or an iron plate the whole width
of the ash-pit, and extending from the said trough to the front of the furnace,
to which I attach an upright plate, in which there is the fire door opening
fitted with a door, also a small door at the bottom of the said front plate for
cleaning under the close part of the bars; the said upright plate extends high.
enough to communicate to the roof of the furnace, and thus inclose the dead or
close part of the grate bars, by which free access of air is excluded therefrom.
In the roof of the furnace, and nearly over the middle of the dead or close part
of the grate bars I form a hole, having its length equal to the whole width of
the grate, and about six inches wide (which I call the feeding hole), and is
carried either perpendicular or sloping through the brickwork, or through a
projecting part of the boiler, as may be found most convenient; the said feeding
hole, if sloping, should be made very smooth on the bottom, on which the coal
in that case will slide. To the outer end of the said feeding hole I attach the
feeding apparatus, either that of which the following is a description, but which
is not new, or those which I shall afterward describe, which are new.
I form
a receptacle, in shape similar to the hopper of a corn mill, (which I call the fire

page_text: feeder,) excepting that the bottom is made oblong, its length being equal to
the width of the grate which it is intended to feed, and its width about nine
inches; the apparatus through which the coal passes from the receptacle is on
one of its sides and close to the bottom, and this aperture is adjusted to
the size of the pieces of coal used by means of a sliding shutter, raised or lowered
as occasion may require, varying from two to five inches; the bottom of the
said fire feeder is an iron plate about twelve inches wider than the lower orifice
thereof, and inclined downward about one in six towards the side on which is
the aperture for discharging the coal, and in the same direction it has a recipro-
cating motion by which the coal resting upon the said iron plate or bottom is
passed through the aforesaid opening in the side of the said fire feeder, and
precipitated over the lower edge of the said plate into the said feeding hole. I
communicate the said reciprocating motion to the bottom plate which moves
through equal space at each end by a shaft extending the whole length of the
sliding plate; near to the extremities of the said shaft I fix two levers of equal
length, to the ends of which by joints and rods I attach the said sliding bottom
plate, which by the reciprocating motion of the said shaft and levers is moved
in a direction transverse to the length of the said feeding hole and aperture in
the bottom of the said fire feeder. In order to prevent any air from entering
the furnace by the said feeding hole, I connect the said fire feeder to the said
the said fire feeder with
feeding hole by a case which incloses the lower part
its moveable bottom plate, making a hole in the said case through which the said
shaft, with its equal levers, is extended, in order that the
motion
necessary
be communicated thereto, by connecting the same with an engine or other conve-
nient power. I construct a rectangular box of sheet or cast iron or other suitable
materials; I make the side thereof, from which the coal is discharged, as long
as the width of the grate that it is intended to feed, its width varying from four
to eighteen inches, its depth also varying generally from one foot six inches
to five feet, according to the local circumstances of its situation, or to the
quantity of coal it is required to hold; it is close at the bottom; the upper end
is open, by which it is filled, but is provided with a close, well fitted cover, to
prevent the introduction of atmospheric air; the side from which the coal is
discharged is moveable in the direction of its own plane and the depth of the
box, being attached thereto by slides or rabbets, in which the said side moves
and fits so closely as to prevent coal passing between it and the said box. The
box, which I call the coal receiver, or for brevity, the receiver, being thus
constructed, filled with coal, and placed perpendicular or inclining towards the
side which is moveable, the said moveable side is forced downward by the
power of a steam engine or other convenient power; the coal will then be
may

page_text: ;
discharged by his own gravity from the receiver over the upper edge of the said
moveable side as it descends; when I apply this said coal receiver, I construct the
feeding hole in a sloping direction, not more than forty-five degrees from per-
pendicular, through the brickwork of the flues, and connect the outer end thereof
with the sides and top of the said receiver, so that the coal discharged therefrom
falls directly into the feeding hole, and is thereby conveyed to the grate, whilst
the atmospheric air is excluded. I also in some cases fix what I have called in the
above description the moveable side, and by the power of a steam engine or
other convenient power, I elevate the receiver when filled with coal, by which
the coal is discharged over the upper edge of the said fixed side; when I thus
discharge the coal by elevating the receiver I make the fixed side wider
than the receiver, and as much higher as the receiver is intended to be raised;
upon the open edges of the receiver in the direction of its height I fix slides
which slide in corresponding rabbets or grooves upon the fixed side, and through
the said fixed side at the height of the receiver from the bottom I make an
opening as wide as the receiver, and about seven inches high, through which the
coal is discharged into the feeding hole, which is also connected to the fixed
side, so as to exclude the air, and in order to prevent the undue admission of
air into the receiver as it is raised its open side continues to slide against that
part of the fixed side which is above the said opening. I wish it to be under-
stood that the above two last described modes of feeding the grate are new, and
I consider as most applicable to furnaces consuming under ten bushels of
coal per day, and in such cases, if local circumstances permit, I make
the receiver sufficiently large to hold coal for one days consumption. No
competent engineer will find any difficulty in communicating from one steam
engine or other power a simple rotary motion to the excentric bearers of the
grate bars, which I make to revolve from three to six revolutions in five
minutes; nor will any engineer find difficulty in borrowing from any convenient
power that which may be necessary to give the reciprocating motion to the
moveable bottom plate of the fire feeder, nor to convey such portion of power
from any convenient source as will be necessary to lower the moveable side of
the coal receiver, or to elevate the coal receiver in such time as will maintain
the required intensity of the fire. But I shall describe methods of doing so
which will be easily understood, and which I use, approve, and recommend.
I attach to the end of one of the eccentric bearers a bevel wheel with which I
connect another level wheel upon an upright shaft, which extends above the
boiler, to any convenient height, where I attach thereto a bevel wheel of about
thirty inches diameter, into which runs a pinion of about five inches diameter,
driven by and fixed upon a shaft extending from the engine or source of power.

page_text: At some part of the line of communication I introduce the means of altering the
speed at pleasure, either by two conical drums, or a series of pullies of various
diameters, or any other well-known means of regulating the speed of a driven
shaft; in order that the speed of the eccentric bearers may be suited to the
nature of the coal, the intensity of the heat, or any other circumstance.
Upon the above-mentioned upright shaft having a bevel wheel at the bottom,
and another of abont thirty inches at the top, and being driven by the
engine, I fix a cam or eccentric curve, which, being brought round by
the revolution of the said upright shaft, may act against a lever con-
nected by a rod and another lever to the said reciprocating shaft, extended
through the hole in the said case, having the two equal levers by which
the sliding bottom plate of the fire feeder is moved in one direction, at
the same time raising a weight connected with and sufficiently heavy
to move the said plate back again in the opposite direction whenever the
cam has ceased to act upon the said lever. In order to regulate the quan-
tity of coal introduced by each movement of the said sliding bottom plate,
I cause the said lever to act against or fall upon a wedge which by moving
longitudinally by being attached to the damper regulator (if there be one)
will encrease or diminish the space through which the said sliding bottom plate
moves, and thereby increase or deminish the quantity of coal introduced. In
applying the necessary motion to discharge the coal from the coal receiver,
whether by lowering the moveable side or by elevating the receiver itself, having
ascertained what quantity of coal it can contain, and also the quantity of coal
needful to be consumed in any given time, say one hour, I communicate a
motion from the upright or lying shaft (by which the eccentric bearers are
driven) to another shaft parallel thereto by the well-known means of two
reversed conical drums and a leather strap, which is constrained by two guide
rollers to run upon any opposite portions of the two drums, and thus afford
means of accurate adjustment of speed. From this driven shaft I connect such
a train of pinions and wheels or screw and wheel as will sufficiently reduce the
speed of a roller, round which I cause a chain to wind, the other end of which is
attached to the moveable side of the coal receiver, or to the moveable coal
receiver, as the case may be, by which means the coal will be discharged at any
required speed within the range of the said conical drums; I also connect the
said two guide rollers of the strap to the damper regulator in such a manner
that as the pressure of the steam increases, the guide rollers moving the strap
between the said conical drums diminish the speed of the discharge of the coal,
and vice versa. I sometimes apply the two last-described methods of introducing
coal, which I state as new, to feed fires of the ordinary construction; and where

page_text: there is no convenient power to be procured by which the receiver can be raised
or the moveable side depressed, as already described, I in such cases attach a
weight by a chain and pulley sufficiently heavy to discharge the coal from the
receiver, which weight is wound up by means of a windlass of sufficient power
when the receiver is depressed or lowered preparatory to its being filled with
coal. But to prevent the precipitate discharge of the coal I construct two
bags, each of which I make somewhat longer than the space through which
the said weight which discharges the coal is intended to move; the said bags I
connect by their open ends to a division having a hole one quarter of an inch
diameter, through which sand may pass from one bag to the other. Through
the said division and transversely with the said hole I make another hole or
opening, through which I introduce a slide of brass or other suitable metal,
having several holes of different area suited to the time in which a bag fall of
sand is intended to pass, and by moving the said piece of brass any of the
graduated holes may be brought to correspond with the said sand hole in the
division, and by that means regulate the time of the discharge of sand from one
bag into the other; the two bags, one of which being fill'd with sand or metallic
powder such as is commonly used in what are called minute or hour glasses,
thus connected by the divisions and transverse regulating slide, I enclose in a
case of sheet iron or other suitable materials corresponding with the size of the
bags, and long enough to enclose both; a hole is made through the middle of
the said case for the admission of the transverse slide having the graduated
holes; the said case I suspend by two trunnions by the middle of its length in
a suitable frame, so that it may be conveniently turned upside down and fixed
in a perpendicular position. This apparatus, which I call the sand regulator, I
place under the said weight, which is made of such dimensions as to go within
the said case and resting upon the upper bag filled with sand, or the said
metallic powder is thereby supported and permitted to fall only as the sand or
powder is permitted to escape into the lower bag; when this is done, and the
weight has followed the sand or powder, the coal will also be discharged from
the receiver, which in order to be refilled must be depressed, and consequently
the weight raised, and being drawn out of the said case of the sand regulator
the lower bag being of full of sand or powder is then turned up (analogous to
the turning up of a sand-glass), and the weight again permitted to rest upon it.
I also in some cases, for the purpose of raising the coal receiver above
described, construct a cylinder of brass or other suitable metal of such length
and diameter that the piston thereof when pressed with a certain hydrostatic
pressure will be sufficiently powerful to raise the coal receiver when filled with
coal; the said hydrostatic pressure I calculate from the most conveniently

page_text: accessible height I can place a small cistern of water or other suitable fluid in
or connected with the premises in which the coal feeder is intended to operate.
To the said piston, which is made accurately to fit the said cylinder, and provided
with a leather packing, I attach a rod, which passing through the top of
the cylinder, in which it is also made tight by a leather collar, is connected to a
chain, which hanging over a pulley or pullies, is at its other extremity fastened
to the said coal receiver. To the upper end of the cylinder I attach a small
metallic pipe passing in the most convenient way to the said elevated cistern,
which I supply with water by manual labour or by any other suitable means.
Upon the said pipe at some easily accessible place I fix a small cork with an
index finely graduated, by which the admission of the fluid into the cylinder is
regulated, and of course the rate of the time of the elevation of the receiver
and discharge of the coal also regulated; the piston being depressed and the
cylinder filled with water, the said small cock is shut, and another pipe, which I
call the exit pipe, attached also to the upper end of the cylinder, but passing
downward to convey the water into some convenient place, and having a cock
upon it, is opened, and the water is discharged by the preponderating weight of
the receiver, which will lower itself and likewise draw up the piston preparatory
to another action. With my said improved or peristaltic grates the smallest
coal may be used; but pieces of coal larger than would pass through in every
direction a ring of four inches diameter must be broken before they are put
into the hopper or into the coal receiver. I have already intimated and I
wish it to be clearly understood, that the improvements which form the subjec
of the present Specification do not consist in the invention or construction of
the fire feeder, which, with the exception of the sliding bottom plate thereof
moving through equal spaces at each end, is already described in my Specifica-
tion of the Invention for which I obtained His Majesty's Royal Letters Patent,
dated the Twenty-ninth day of June, in the year One thousand eight hundred
and nineteen, for "Certain Improvements in Steam Engines, and the Furnaces
of Steam Engines, by which a Saving in the Consumption of Coal is effected, and
the Combustion of Smoke is more completely attained," though I have thought
it adviseable for the sake of perspicuity to repeat here many parts of the
description given in the Specification alluded to, nor do the improvements which
form the subject of the present Specification consist in inclining the grate bars,
which is not new, nor in the feeding hole in the roof of the furnace, nor in the
invention or construction of the cylinder and piston pressed with a column of
water, by which the coal receiver is discharged. But the improvements which
form the subject of the present Specification consist, first, in the means, that is,
the motion communicated to the grate bars which I now employ and have before

page_text: described, by which the fire is progressively conveyed through the furnace, and
the clinkers and other incombustible matter deposited in a close receptacle,
constituting what I designate a peristaltic grate, and which I apply to the
furnaces for steam boilers, coppers for brewing, stills and evaporating vessels, to
reverberatory furnaces for melting or refining metals, to furnaces for heating
gas-retorts, to furnaces for stoves or ovens for annealing glass or cast iron, or to
any furnace to which the said peristaltic grate is applicable; and, secondly, in
introducing coal by means of the coal receiver described before upon my said
peristaltic grates or other grates to which the same may be applicable, and
regulating the same by means of the said sand regulator, or the said hydrostatic
cylinder and piston already described.
In witness whereof, I, the said William Brunton, have hereunto set my
hand and seal, this Twenty-third day of December, in the year of our
Lord One thousand eight hundred and twenty-two.
his deed was signed, sealed, and
delivered, taken and acknowledged,
by the within-named William
Brunton, at Birmingham, in the
County of Warwick, this Twenty-
third day of December, in the year
of our Lord One thousand eight
eight hundred and twenty-two,
WILLIAM (L.S.) BRUNTON.