Improvements in and relating to Mechanical Stoker Bars, and like Furnace Grates and Bars.
Year: 1897

page_text: Date of Application, 27th Feb., 1897
Complete Specification Left, 23rd Nov., 1897-Accepted, 24th Dec., 1897
PROVISIONAL SPECIFICATION.
Improvements in and relating to Mechanical Stoker Bars, and like
Furnace Grates and Bars.
I, ANDREW PILLATT, of the firm of A. Pillatt and Company, of Queen's Road
Works, in the town and county of the town of Nottingham, Furnace Engineers,
do hereby declare the nature of this Invention to be as follows:-
My Invention has reference to improvements in and relating to mechanical
stoker bars and like furnace grates and bars in which such bars have a recipro-
cating motion for the purpose of being automatically cleared from clinkers and
other incombustible matters, and it has for its object the regulation of the
amount of air passing through hollow mechanical stoker bars, and the attain-
ment of durability for the bars and economy in the consumption of fuel.
For the purpose of my Invention I construct the fire bars hollow, or with a
passage from end to end, or partly hollow, and preferably as described in the
Specification of my Patent No. 13, 371 of 1895; and I arrange a suitable damper
or air-regulating device below the said hollow bars. The bars may be cast in
one piece and be of sufficient length to reach from front to back of the furnace,
and are provided with a suitable number of lateral, or other appropriately disposed,
air inlets. Instead of the passage through the bar passing in a straight line from
end to end, as heretofore, at the back end the passage is curved downwards and
the outlet or aperture is arranged in the bottom face thereof, the end portion of
the bar being left solid. The bridge plate or support on which the bars slide
is provided with a cast iron or other suitable metal box extending the width of
the grate; and said box or bridge plate chamber presents an opening towards
the bottom faces of the bars. The bars, under the action of the usual cams or
eccentric at the front of the grate, slide upon, and are supported at the back by
the said box or chamber, and form a cover therefor, the solid end of the bar
pro-
jecting beyond the back wall of the box or chamber a distance slightly exceeding
the stroke or throw of the bars. The downwardly inclined openings in the bars
are so designed, relatively to the opening at the top of the box, that whether the
bars be at the back or at the front end of their stroke, or in any intermediate
position, there shall be free passage of the air therefrom into the box, and the
air passing from any of the bars to the flue will have to pass first through the
box. The box has an outlet which may advantageously be provided with a
grating (to prevent cinder or clinker entering it) and through which outlet the
hot air passes from the bars to the flue. This outlet is capable of regulation by
means of a door or damper arranged within or outside the box as may be found
convenient, the wall of the box on which said damper or regulator is arranged
being suitably undercut or inclined. The box is further provided with dust
doors, or any other like suitable means, by which it may be cleared from dirt.
The back end of the hollow bars is preferably rounded at top so as to facilitate
clinker, and the like, falling off clear of the damper or regulator.
Or the bars may be shaped somewhat like a syphon at the back, the end of the

page_text: passage through the same being bent towards the front of the furnace below the
grate and forming a pipe adapted to slide through the wall of the bridge-plate
box or chamber, for the purpose of admitting the heated air from the bars thereto
in all positions of the bars. Or the ends of the bars may be solid and the passage
through the bars be connected with the bridge-plate box or chamber by means
of sliding tubes entering said box or chamber from the front.
According to another modification I dispense with the bridge-plate box or
chamber and I arrange a slotted plate below the downwardly inclined air out-
lets at the back ends of the bars, the said slotted plate being supported by the
bridge plate and capable of adjustment and regulation as to its position in such
a way as to alter the area of the outlet for the air from the bars.
Or instead of the said slotted plate, I may hinge a door damper, or regulator
upon the upper part of the bridge plate, in such a manner that, in all positions of
the bars, the air will pass from the downwardly inclined air outlets between the
bottom faces of the bars and said door or damper, the space between the bottom
faces of the bars and the door or damper being variable according to the angle
to which said door or damper is adjusted.
Improvements in and relating to Mechanical Stoker Bars, and like
Furnace Grates and Bars.
I, ANDREW PILLATT, of the firm of A. Pillatt and Company, of Queen's Road
Works, in the City of Nottingham, Furnace Engineers, 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, refer-
ence being had to the accompanying drawings and to the letters and figures
marked thereon, that is to say:
My Invention has reference to mechanical stoker bar and like furnace grates
and bars, in which the bars have a reciprocating motion imparted to them for
the purpose of clearing them from clinker and other incombustible matter, and
it has for its object to construct such bars with their longitudinal air passages curved
or inclined downwards at the rear or bridge end, and to provide means whereby the
hot air passing through them may be regulated, so obtaining great durability
therefor and economy in the consumption of fuel.
In carrying out my Invention I construct the bars hollow or with passages
from end to end, or partly hollow, and I arrange below them a suitable air regu-
lating device. The bars are advantageously cast in one piece, and of a sufficient
length to extend from front to rear of the furnace. I further provide them with
a suitable number or series of lateral (or other appropriately disposed) air inlets
communicating with the longitudinal passage, as described in the Specification of
my Letters Patent No. 13371 of 1895, but instead of this passage passing in a
straight line from end to end, as heretofore, it is curved downwards at the rear
end, and the outlet is arranged in the bottom face of the bar, the end portion
being left solid. The bridge plate or support on which the bars slide, is pro-
vided with a cast iron or other metal box or chamber extending the width of

page_text: the grate, and said box presents an opening towards the bottom face of the bars,
the solid end of said bars projecting beyond the back of the box or chamber a
distance slightly exceeding the stroke or throw of the bars.
The outlet or opening through the box or chamber is capable of regulation
by means of a door or damper arranged on said box and adapted to be operated
by a rod, or other suitable means.
I may however dispense with the box or chamber, and provide the bridge plate
with an opening or passage arranged to be regulated by means of a damper or
door hinged directly to the said bridge plate.
And in order that my Invention may be readily understood, I will describe
the same fully with reference to the annexed drawings, in which:
Fig 1 is a longitudinal section showing the bridge plate end of a mechanical
stoker bar furnace grate constructed according to the Invention.
Fig. 2 is a like section of a modified form of bridge plate box and stoker bar.
Fig 3 is also a like section of a further modified arrangement in which the
box or chamber is dispensed with.
Fig 4 is a plan of the bridge plate and damper represented in fig 3.
Referring to fig 1, a is a stoker bar which may be of any of the usual forms
of hollow bar, but having a solid end 6 and the longitudinal passage c curved
or inclined downwards as at c¹. By preference, these bars are provided with a
series of lateral air inlets in their web communicating with the passage c, as
described in the specification of my aforesaid patent. Said bars are caused to
move under the action of the usual cams or eccentrics at the front of the grate,
and slide upon and are supported at rear by the box or chamber d. In the top
of this chamber is an opening e which extends nearly the width of the furnace,
or of that part occupied by the hollow stoker bars a, and the extent of the open-
ing from tog is equal to the air passage c¹ plus the throw of the stoker bar,
the position of which at the end of its stroke is indicated by dotted lines. The
downwardly inclined air passages c¹ in the bars are so designed relatively to the
openings e in the box or chamber, that whether the bars he at the backward, or
forward, end of their stroke, or in any intermediate position, there will be free
passage of the air therefrom into the box or chamber, and the air passing from
any one of the bars to the flue will have to pass first through the said box or
chamber.
The box or chamber is provided with one or more dirt or soot doors h, and with
a grating i through which the hot air passes into the flue, the outlet area being
regulated by a flap or damper j operated by a rod or bar k.
The rear end of the hollow bars is, by preference, rounded off in order to facili-
tate clinker and the like falling clear of the damper.
In the modification shewn in fig 2. the end of the stoker bar is in the form of
a syphon 1, and is arranged to project into the box or chamber in all positions
of the bar, the damper ; being, in this arrangement, at the bottom of said box or
chamber. The hot air from the bars, after entering the box, escapes into the
flue on the damper being more or less opened by means of the rod or bar k; and
by arranging the damper at the bottom of the box it forms both a damper and
a soot or dirt door.
In the modification shewn in figs 3 and 4, the box or chamber d is dispensed
with, and the damper j is hinged directly to the bottom of a slotted bridge plate
or frame d, and in such a manner that the hot air will pass from the down-
wardly inclined air outlets through it, the extent of opening of such damper being
regulated by the rod or bar k, as in the previous arrangements.
The centre grate bar, or bars, and those at the sides of the furnace are, in most
cases, formed with the longitudinal passage c extending throughout the same, and
are not acted upon by the damper.
It is obvious that various modifications may be made in the construction of the
bridge plate and damper, and in the curved ends of the hollow bars without
departing from the nature of my Invention.

page_text: Having now particularly described and ascertained the nature of my said In-
vention and in what manner the same is to be performed, I declare that what I
claim is:
1. Mechanical stoker bar furnace grates having hollow bars the longitudinal
passage in which is curved or inclined downwards at the rear end.
2. In mechanical stoker bar furnace grates having hollow bars, as above
claimed, the arrangement of a damper in such a manner that the air passing
through the hollow bars can be regulated and controlled, substantially as
described.
3. In mechanical stoker bar furnace grates, hollow bars having their longitu-
dinal passage downwardly curved or inclined at the rear end and provided with
a series of laterally disposed air inlets, in combination with an air regulating
damper arranged below the bars and forming at the same time a dirt or soot
door, substantially as described.
4. In mechanical stoker bar and like furnace grates, hollow bars having their
longitudinal passage downwardly curved or inclined at the rear end and provided
with lateral air inlets in their web or rib, and adapted to slide upon a box or
chamber or upon a bridge plate having an opening, or openings, coinciding with that
in the said downwardly curved or inclined passage, so that the hot air passing
through the bars to the flue can be regulated by means of a damper arranged
upon such box, or bridge plate, substantially as described.
5. The modified arrangement wherein the hollow stoker bars are in syphon
form and are adapted to project into the box or chamber (d) whatever may be
the position of such bars, substantially as described with reference to fig 2 of
the drawings.
E
6. My improvements in mechanical stoker bar and like furnace grates and
bars, substantially as hereinbefore described and illustrated in the annexed
drawings.
S ESESC
D1 L
T
1
100%
his 23rd day of November 1897.
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, & 5A Market Street, Nottingham.
Agent for the Applicant.