Improvements in Furnace Grates.
Year: 1894

page_text: Date of Application, 16th Jan., 1894-Accepted, 10th Mar., 1894
Improvements in Furnace Grates.
I, TEILE HENRY MÜLLER, residing at 1521 Montgomery Avenue, in the City
of Philadelphia, in the County of Philadelphia, in the State of Pennsylvania, one
of the United States of America, Engineer, do hereby declare the nature of my
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
My invention relates to furnace grates and has for its object the production of a
grate which will be of such a construction that, among other advantages resulting
therefrom, low grade fuels can be economically burned thereon, that smoke will be
avoided, that the fuel and ashes can be automatically handled, that fuels which only
burn from below and also such as will burn from above can be used, and that forced
draft can be employed without the necessity of a closed ash pit. To carry out these
objects and also to improve the construction of devices of this class my invention
consists mainly in the arrangement of an inclined series of shelves to support the
fuel; that is, a series of shelves where each shelf is arranged below, and extends
further forward than the shelf next above it, some or all of the shelves being
preteraviy
rforations therein to serve as air ducts so that they
will serve as a support for the fuel and will at the same time serve as a conduct of
air to the fire. My invention further consists in the arrangement of plungers
between some or all of the shelves whereby the fuel can be automatically stoked,
and further, in various improvements which will be more specifically pointed out in
the claims appended to and forming part of this Specification.
My invention is best described in connection with the drawings in which it is
illustrated and in which,
Figure 1 is a vertical section of a furnace grate on a line corresponding to the
line of Figure 4 showing one form of my improved grate; a portion of a boiler
being shown above the grate in elevation.
Figure 2 is a view similar to that shown in Figure 1 showing a modified form of
driving mechanism for the plungers arranged between the shelves.
Figure 3 is a view similar to that shown in Figure 1 illustrating a modified
arrangement.
Figure 4 is partly a plan view of the grate shown in Figure 3, a part being
shown in section on the line y-y of Figure 3.
Figure 5 is a sectional view on the line -2 of Figure 2 showing a modified
form of plunger.
Figure 6 is a similar view to Figure 5 showing a modified mode of operating the
plungers.
Figure 7 is an enlarged detail view of a portion of the device shown in
Figure 1.
Figure 8 is a plan view of a shelf removed from the furnace and having a
corrugated front, and
Figure 9 is a further modified form of a shelf.
A is a furnace provided with suitable side-walls A'; B a boiler: extending
between these walls A¹ is an inclined series of hollow shelves a, that is to say, each
shelf extends further forward than the shelf next above it; these shelves are
preferably provided on the furnace side with openings or perforations a' which may
obviously be of any desired form or size, and which are adapted to serve as nir
ducts, air being forced into the hollow shelves at any suitable point from a blower
or other air forcing apparatus. In construction it has been found convenient to
introduce the air into the hollow shelves at their ends, either one or both ends
serving as inlets and any suitable conduit is adapted to conduct air thereto. Where

page_text: the boilers are built singly the ends of the shelves may extend through the furnace
walls as indicated in Figure 8 and the air conduit may be connected to the various
shelves outside the walls: preferably at one end of the shelf, the other end being
covered by a handhole and serving to clean out the interior of the shelf when
necessary. When a battery of boilers are built a very convenient arrangement is
to build a conduit E for air in the partition walls of the furnace and provide
openings as d³ from the condnit to the several shelves as indicated.
To preheat the air I prefer to arrange part of the air conduit D in the lower
part of the furnace where the air therein is heated from the hot ashes, any suitable
opening admitting the heated air to the conduit or conduits É: small air
outlets d may be provided in the conduit D, as shown, if desired.
It is obvious that the shelves may be of any shape that may be found advan-
tageous, they may be very advantageously made however, with backwardly inclined
faces, as shown, and, to strengthen the metal and prevent warping, the face may
advantageously be made corrugated, as shown in Figure 8 or any other desirable
contour may be given to the several shelves. The shelves are arranged at a
suitable distance apart and in the spaces a between them are situated stoking
plungers c. These plungers may be rectangular boxes fitting in the spaces a² or
may be formed as shown in Figures 5 or 6. In Figure 6 the plunger is shown
with a series of small holes c¹ and in Figure 5 the plunger c is shown with a similar
series of small holes c¹ and provided with a damper having a series of
holes which, when put in proper position are adapted to register with the holes c',
so that a slice bar can be put through the openings c' of the plunger and damper
to stir up
the fuel and prevent its forming clinkers. Any suitable means can be
arranged to reciprocate these plungers; it is obvious however, that it is most
convenient, especially, where several boilers are arranged abreast, to operate all
the plungers by means of a common shaft or from a common source of power. In
Figure 1 S is a shaft having an eccentrics and adapted on rotation to reciprocate a
bar F by means of two lugs 11 secured to the har. Bell crank levers fare pivoted
to the shelves and secured at one end to the rod F, to the other end of the bell
crank levers are pivoted links f¹ secured to the plungers c. The top plunger which
is directly under a hopper H, is pivoted to an arm on the upper bell crank lever
and in order to adjust the throw of this plunger the connection between the plunger
and the lever is made adjustable. A convenient mode of doing this is shown in
Figure 7 where N is a link pivoted on the lever f³, n a sleeve screwed on to said
link and fitting through a hole n in the plunger c, a nutlock n' securing it in
position. The sleeve n extends through the hole n and a sleeve nut n³ having a
cut out portion n* which fits over the sleeve n is screwed on the outer end of the
link N, a nutlock n being arranged to hold it in position. By screwing the nut n³
in or out the space between the head of the sleeve n and the nut will be increased
or diminished and the throw of the top plunger c thereby adjusted. It is obvious
that the same or a similar device, if desired, be arranged on any or all of the
plungers. Secured to the bar F is a lever f which is connected by means of
link to the grate G supported on links G¹ whereby the grate G is given a
reciprocatory motion along with the plungers so that the ashes are constantly and
automatically removed from the bottom of the grate causing a gradual settling of
the fuel. In Figures 2, 5 and 6, the plungers are shown actuated by vertical
shafts S¹ having eccentrics &' arranged thereon; motion is communicated from the
eccentrics on the shaft S' to the plungers, either immediately by the links fas
shown in Figure 6; or by means of levers k pivoted at ; as shown in Figure 5, a
slot is preferably arranged whereby the throw of the plungers may be adjusted
by securing the head of the link f¹ nearer or further from the pivotal point of the
lever k; obviously, however, suitable shifting eccentrics may be used to adjust the
throw of the plungers. Motion may be given to shaft S¹ by means of suitable
bevel gears or any other suitable means. In Figure 3 another system of links is
shown which is oscillated by a crank F pivoted at F. On various points of this
crauk as at ff" are pivoted links which serve to actuate the plungers either

page_text: directly or through the medium of the other bell crank levers and links. In order
to adjust the throw of the whole series of plungers the connection of the power
shaft S' to the crank F is made adjustable and consists of a pin as p, removably
secured in a slot in the crank by means of a hand wheel P; and to further adjust
the motion of the two upper plungers a slot T is provided as shown, whereby the
range of oscillation of the lever pl may be adjusted by adjusting the end of the
link in the slot T. The lever p¹ pivoted at p³ has secured thereto pins p³ and
the links f¹ which serve to connect the plungers to the lever plare provided with
handles and slotted heads f which fit over the pins på whereby by lifting up a
link by means of its handle the plunger connected therewith may be put out of
operation and will not be put in again until its link f' has its head ƒ dropped over
its proper pin p. This construction is obviously not limited to any particular
plunger but may be provided wherever found advantageous. The link pivoted
to the crank Fat serves to reciprocate not only the lower sets of plungers but
also by means of a link 10 and a bell crank lever g' to reciprocate the grate bars G7
and slowly remove the ashes. The grate G whose grate bars fork into the grate
bars G7 is adapted to be turned over or shaken by means of the rod g. The modes
of actuating the plungers can be multiplied indefinitely, and I do not wish to be
considered as limiting myself to any particular mode of so doing.
H is a hopper which may couveniently be arranged above the grate and I
preferably provide it with a gate h having a handle h¹ whereby burning back may
be prevented.
In the device shown in Figure 3 I not only provide for pushing the fuel over the
front of the transverse shelves, but also provide a passage formed beneath the
shelves a and walls a. The plungers reciprocate across this passage h³ between
the shelves a and walls a' and push the fuel forward through the passages a³. I do
not find it advantageous to extend this passage ³ down to the bottom of the inclined
grate since by the time the fuel is near to the bottom of the grate it has become
very nearly completely ignited and I arrange it in front of the shelves where it
may have the benefit of the forced draft.
Any suitable means may be used to remove the ashes. In Figure 1 a pan G³
standing under the front end of the grate G is adapted to receive the ashes pushed
from that grate on its reciprocation a flange g being preferably arranged as shown
on the lower part of the hot air conduit to prevent the ashes being pushed back
toward the back part of the ash pit. In Figure 2 a car K rolling on suitable
tracks is shown situated underneath the grate G which is adapted to be
reciprocated by means of the link F and can be used under a whole battery of boilers.
When a battery of boilers is used the air can be conveniently pumped through a
passage at D¹ from whence it is led by ducts d' into the several conduits D under
the individual boilers B. It is obvious, of course, that air may be introduced in
any other way, if desired.
h
The action of the grate is easily understood. Fuel is poured into the hopper H,
the gate / open, and the automatic plungers set operating, the fuel in the hopper
falling down through the opening is pushed forward by the plungers over the
inclined series of shelves and in being pushed by the plungers the fuel is continually
turned over and thoroughly ignited so that when it is finally pushed to the lower
shelves combustion is complete. In the grate shown in Figure 3, which is especially
adapted for use with fuels which smoke badly, the fresh or green fuel is pushed
underneath the heated mass of fuel and the gases arising therefrom are compelled
to pass through this heated mass, which results in the complete combustion of the
gases and in the prevention of smoke.
While I have shown what I deem the best modes of arranging my grates and
the best systems of driving mechanisins therefor, it is evident that many modifica-
tions both in arrangement and details can be made without departing from the
spirit of my invention.
I believe I am the first to combine with an inclined grate having means for
feeding fuel to its upper end, a constantly acting device such as grates G G³ G³,

page_text: as shown in Figures 1, 2 and 3 respectively, for drawing the ash away from the
base of the grate with regulated speed and so facilitate the gradual settling of
the fuel down the incline and I therefore do not limit myself as to this feature of
my apparatus to the shelf form of grate.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim, is
First. In a furnace for generating heat by the combustion of fuel, a furnace
grate consisting of a series of hollow shelves extending across the furnace and
constituting air conduits as well as grate bars, said shelves being arranged so that
each one of the series will lie below and extend further forward than the one
above it and having air passages leading from its central cavity through its face
into the furnace.
Second. In a furnace for generating heat by the combustion of fuel, a furnace
grate consisting of a series of hollow shelves extending across the furnace and
constituting air conduits as well as grate bars, said shelves being arranged so that
each one of the series will lie below and extend further forward than the one above
it, and having air passages leading from its central cavity through its face into
the furnace in combination with an automatic feed hopper at the top of the grate.
Third. In a furnace for generating heat by the combustion of fuel, a furnace
grate consisting of a series of hollow shelves extending across the furnace and
constituting air conduits as well as grate bars, said shelves being arranged so that
each one of the series will lie below and extend further forward than the one
above it and having backwardly inclined faces and air passages leading from its
central cavity through said faces into the furnace.
Fourth. In a furnace for generating heat by the combustion of fuel, a furnace
grate consisting of a series of shelves, each shelf being arranged below and
extending further forward than the shelf above it, a stoking plunger or plungers
arranged to operate in the space between the overlapping shelves, but not con-
stituting an essential part of the fuel supporting grate and means for introducing
air beneath the mass of fuel resting on the grate bars to maintain the combustion
of said fuel.
Fifth. In a furnace for generating heat by the combustion of fuel, a furnace
grate consisting of a series of hollow shelves extending across the furnace and
constituting conduits as well as grate bars, said shelves being arranged so that
each one of the series will lie below and extend further forward than the one above
it and having air passages leading from its central cavity through its face into
the furnace, and stoking plungers arranged in the spaces between the shelves.
Sixth. In a furnace for generating heat by the combustion of fuel, a furnace
grate consisting of a series of hollow shelves extending across the furnace and
constituting air conduits as well as grate bars, said shelves being arranged so that
each one of the series will lie below and extend further forward than the one
above it, outlet passages a¹ leading from the central cavity in the shelves through
their faces into the furnace, openings d³ at the end of each shelf for the admission
of air into the central cavities of said shelves and a conduit for conducting the air
to the various shelves.
Seventh. A grate having a series of shelves, each shelf being arranged below
and extending forward of the shelf above it, plungers arranged in the spaces
between the shelves, means for reciprocating the plungers and means for adjusting
the throw of said plungers.
Eighth. A grate having a series of hollow shelves, each shelf being arranged
below and extending forward of the shelf above it and having an inclined corrugated
front face and provided with air outlets substantially for the purpose specified.
Ninth. A grate having an incliued series of shelves extending across the
furnace and a passage extending down behind one or more of the shelves
substantially as described.

page_text: Tenth. A grate having an inclined series of shelves extending across the
furnace, a passage extending down behind one or more of the shelves and
plungers arranged to reciprocate in the spaces between the shelves.
Eleventh. A grate having an inclined series of hollow shelves a extending
across the furnace and having outlets for air in the faces of said shelves, a passage /³
extending down behind the perforated shelves, a series of plungers arranged in the
spaces between the shelves and means for reciprocating the plungers.
Twelfth. The combination in a grate of an inclined series of hollow shelves a
extending across the furnace and having perforations a' in the shelves for the
passage of air, a passage ³ extending down from the top and behind the shelves
for a portion of the length of the grate, plungers arranged to reciprocate across
the passage, and plungers adapted to reciprocate in the spaces between the
shelves below the passage.
Thirteenth. The combination in a grate with a series of shelves as described,
having spaces between the shelves, of a plunger or plungers arranged to operate
between the shelves and having holes substantially as specified and so that a
slice bar can be introduced to stir the fire.
Fourteenth. The combination in a grate with a series of shelves as described
having spaces between the shelves, of a plunger or plungers arranged to operate
between the shelves and having holes c' and a sliding damper e* with corresponding
holes substantially as and for the purpose specified.
Fifteenth. A grate having an inclined series of shelves a extending across the
furnace, said shelves being provided with slots or perforations for the escape of air,
openings leading into the ends of the shelves, a passage or passages É leading
to the shelves and serving to convey air thereto and a passage as D so arranged as
to be heated by the hot ashes and the products of combustion all substantially as
specified and so that hot air may be fed into the furnace.
Sixteenth. The combination in a grate with an inclined series of shelves extending
across the furnace and having spaces between the shelves and a series of plungers
adapted on being reciprocated to stir the fuel and push it down the series of shelves,
of a grate at the bottom of the series of shelves, and means for reciprocating or
rocking said grate.
Seventeenth. The combination in a grate with an inclined series of shelves as
described, having spaces between the shelves, of a hopper adapted to deliver fuel
to the series of shelves and a series of plungers operating between the shelves
adapted to stir the fuel and push it down the inclined shelves.
Eighteenth. The combination in a grate of a hopper, a gate independent of the
stoking mechanism arranged to cut off the interior of the furnace from the fuel in
the hopper whereby the burning back of the fire is prevented and an inclined series
of horizontal shelves forming the grate surface.
Nineteenth. The combination with a hopper from which fuel is fed to a furnace,
of a transverse shelf extending below the mouth of the hopper, a grate situated
below said shelf, a stoking plunger operating to push forward and stir the fuel fed
from the hopper and a gate separate from said plunger to prevent burning back
substantially as and for the purpose specified.
Twentieth. In a furnace for generating heat by the combustion of fuel, the
combination with a furnace grate consisting of an inclined series of shelves described
having spaces between the shelves, means for introducing air beneath the mass of
fuel on the grate, means for reciprocating said plungers and links adapted to secure
the plungers to the beam for reciprocating them, said links being so arranged as to
be disconnected at will whereby any particular plunger may be put out of action if
desired.
Twenty-first. In a furnace for generating heat by the combustion of fuel, the
combination with a furnace grate consisting of an inclined system of shelves as
described, having spaces between the shelves, plungers arranged in the spaces
between the shelves, a suitable motor, links secured to the plungers and having

page_text: notches adapted to engage with the pins on the motor, all as specified and so that
any plunger can be disconnected at will from its actuating motor.
Twenty-second. In a furnace for generating heat by the combustion of fuel, the
combination with an inclined grate, of means for feeding fuel at the top of said grate,
means for introducing air beneath the mass of fuel on the grate to maintain
combustion and automatic means for constantly withdrawing ashes from the bottom
of the grate.
Twenty-third. In a furnace for generating heat by the combustion of fuel the
combination with a furnace grate consisting of a series of shelves extending across
the furnace, each shelf being arranged below and extending further forward than
the shelf above it, of means for introducing air beneath the fuel on the grate to
maintain combustion, a stoking plunger or plungers arranged to operate in the
spaces between the shelves and automatic means for constantly withdrawing ash
from the bottom of the grate.
Twenty-fourth. In a furnace for generating heat by the combustion of fuel,
the combination with a grate consisting of a series of shelves extending across the
furnaces, each shelf being arranged below and extending further forward than the
shelf above it, of means for feeding fuel at the top of said grate, a stoking plunger
or plungers arranged to operate in the spaces between the shelves, means for
introducing air beneath the mass of fuel on the grate and automatic means for
constantly withdrawing ash from the bottom of the grate.
1004
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.