IMPROVEMENTS IN MECHANICAL STOKERS FOR STEAM BOILER AND OTHER FURNACES
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, CONRAD CHRISTIAN SEVERIN KNAP, Engineer, of No Eleven, Queen Victoria
Street in the City of London do hereby declare the nature of my invention
for IMPROVEMENTS IN MECHANICAL STOKERS FOR STEAM BOILER AND OTHER
FURNACES to be as follows:-
I divide the firegrate in two parts, the front portion having moveable gratebars
which propel the fuel towards the back portion of the grate, which has stationary
bars.
The fuel being fed onto the grate, just inside the deadplate, in any convenient
manner, is propelled towards the back by means of pushers working underneath
the deadplate assisted by the longitudinal motion of the firebars.
The back end of these moveable firebars rest preferably on a rocking bearer,
while the front end only slides, as actuated by the motion of the stoker.
The pushers are pieces of iron or firebrick resting on the fixed bars and attached
to, and sliding backwards and forwards, with the moveable bars.
The attachment to the moveable bars is preferably made by snugs cast on the
bars, between which trunnions cast on the pushers drop.
I prefer to have two or more fixed bars to every moveable, thus making the
space between the moveable bars wider than the moveable bar itself, and in which
space the pusher scrapes, but do not bind myself to this proportion between the
width of the fixed and moveable portions.
I likewise prefer to keep the level of the top of the fixed bar, where the pushers
work, above the level of the moveable ones.
The mode of actuating the motion of the firebars with the pushers attached is
indifferent, as long as the mechanical means employed produce the requisite
backwards and forward motion.
The fixed portion of the grate is preferably inclined upwards, from front to back,
to prevent the fuel being pushed over into the pit, or space, behind the grate, before
being perfectly consumed.
The advantages of this grate, as here described, are, that the travel of the fuel
over the grate is improved, and that the admission of air and breaking up of the
coal as required to insure combustion are provided for in an improved manner.
I claim in this my Invention for "Improvements in Mechanical Stokers for
Steam Boiler and other Furnaces" the combination of a moveable and a fixed grate,
and mode of propelling the fuel substantially as above described.
Dated this eighteenth day of February 1884.

page_text: I, CONRAD CHRISTIAN SEVERIN KNAP of No Eleven, Queen Victoria Street in
the City of London, Engineer; do hereby declare the nature of said invention
for "IMPROVEMENTS IN MECHANICAL STOKERS FOR STEAM BOILER AND OTHER
PURPOSES," and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
--
I divide the fire grate in two parts, the front part. having moveable grate bars,
which propel the fuel towards the back portion of the grate, which has stationary
bara..
The fuel being fed onto the grate just inside the dead plate, in any convenient
manner, is propelled towards the back by means of pushers working underneath
the dead plate, assisted 'by the longitudinal motion of the fire bars.
The back ends of these moveable firebars rest preferably on a rocking bearer,
while the front end only, slides, as actuated by the motion of the stoker.
The pushers are pieces of iron or fire-brick resting on the fixed "bars and attached
to, and sliding backwards and forwards with the moveable bars.
+
The attachment: to the moveable bars is preferably made by snugs cast on the
bars, between which trunnions cast on the pushers.drop.
+
I prefer to have two or more fixed bars to every moveable bar, thus making the
space between the moveable bars wider than the moveable bar itself, and in which
space the pusher scrape, but I do not bind myself to the proportion between the
width of the fixed and moveable portions.
I likewise prefer to keep the level of the top of the fixed bar where the pushers
work, above the level of the moveable ones.
The mode of actuating the motion of the fire bars with the pushers-attached is
indifferent, so long as the mechanical means. employed produce the requisite
backward and forward motion:
The fixed portion of the grate is preferably inclined upwards, from front to back,
to prevent the fuel being pushed over into the pit, or space, before being perfectly
consumed.
.
The advantages of this grate, as here.described, are that the: travel of the fuel
over the grate is.improved, and that the admission of air and breaking up of the
coal as required to ensure combustion are provided for in an improved manner.
Having described the nature of my invention, I will proceed to describe with
reference to the accompanying Drawings, the manner in which the same is to. be
performed.
Figure 1 represents a longitudinal vertical section of .a. steam boiler or other
furnace provided with mechanical arrangements or expedients for moving- and
operating the fire bars of the grate, constructed according, to my invention.
Figure 2 is a front elevation of a furnace provided with my improvements, and:
furnished with a Knap Stoker.
Figure 3 is a plan of the portion of a grate exhibiting the position of the fixed
and movable firebars with respect to the pushers, also shewing the movable fire:
bars operating shaft.
The same letters of reference indicate the same parts in the several figures of the
Drawings.
The fire grate of the furnace is divided into two parts—The partly movable and
4

page_text: front part A propel and travel forward the fuel towards and-upon the fixed back
part. B.
a, a are the movable bars of the front portion of the grate, and b, b are pushers
or pieces of iron or fire-brick provided with trunnion like ends b², 6These
pushers propel the fuel resting upon the fixed bars of the grate towards the fixed
back bars B-The reciprocating motion of the movable fire bars a, a and the
pushers b, b. carried by them receive their motion through the lever operating
shaft c which has a to and fro' sliding motion given to it by the lever d, d best
seen in figure 2-e is the slide plano or opening within which the shaft c movos,
so as to give the requisite longitudinal to and fro' movement to the bars and
pushers The said movable bars a, a are provided at their back ends with rocking
bearer supports f for giving the requisite rising, falling and longitudinal movement
to the bars, to which they are attached or supported-a, a³ are snugs on the top
edges of the fire bars a between which the trunnion arms 6 of the pushers b drop
and rest-The movable bars a are forked at their front ends, which embrace and
rest upon the sliding shaft c-g, g are the intermediate fixed bars which alternate
in pairs or threes; or other number between the movable bars a, a as best seen in
the plan figure 3-These fixed front bars are raised a little above the level of the
movable bars and are supported on a fixed bearer h-The stationary bars b are the
same width as the combined fixed and movable front bars of the furnace, and rest
upon fixed bearers or supports i, ij is a chain for opening the clinker door k, and
is the clinker pit-m is the bridge of the furnace n is the fire place-o is the
dead plate p is the furnace.
Fuel being fed onto the grate of the furnace from the hopper and through the
delivery spout q rests just inside the dead plate and is propelled towards the back
of the grate by the stoker moving the fulcrum levers d, d backwards and forwards.
-The said levers d are affixed on the movable fire bar carrying shaft c which is
capable of sliding to and fro within a guide or cut away slot e, so that on fuel
resting upon the front grate having been deposited there by a mechanical or other
stoker, the coal or fuel is propelled towards the back of the furnace grate by the
backward and forward movement imparted to the fulcrumed levers d, d by the
stoker The motion of the said levers imparts a reciprocating, or a to and fro
movement to the fire bars a and pushers b-The fire bars a have also an inde-
pendent rising and falling motion at the fulcrumed end a³ by the movement of the
rocking bearer f, carried by the bearer support ƒ³.
The advantages of the arrangements hereinbefore described are, that the travel of
the fuel over the grate is improved, and the admission of air and the breaking up
of the coal or clinkers as required to ensure good combustion, are provided for in a
simple and efficient manner.
The pushers for causing the travel of the fuel over the back of the bars to the
fire grate, slide upon the intermediate fixed bars, by their trunnion arms engaging
between the snugs on the top of the movable bars.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
First The improvements in fire grates for steam boiler and other furnaces as
herein before described and illustrated in the several figures of the Drawings; that
is to say, a divided fire grate, in two parts, the front part having moveable with
alternating fixed grate bars, while the back of the grate has stationary bars only-
The fuel delivered on the front grate is made to travel towards the back, by the
combined reciprocation and slight rising movement of the moveable bars and
pushers, the parts being arranged, combined and operating in the way and for the
purpose as described.
Secondly-The improvements in steam boiler and other furnaces, for imparting the
necessary travel to the fuel by the combined action of the sliding movable bars a
with rocking boarers of combined with pushers b and its trunnions 6" carried and

page_text: supported by the lugs a² on the movable bars a-The combined motion of the
movable bars a and pusher 6 being effected by fulcrum levers d fixed to the shaft o
upon which the ends of the movable bars rest, also the slide c within the framing
of the fire place as described and illustrated.
Dated this 12th day of November 1884.