IMPROVEMENTS IN FURNACES AND MECHANICAL STOKERS AND IN ARRANGEMENTS AND PARTS CONNECTED THEREWITH
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by John Cresswell Brentnall at the
Office of the Commissioners of Patents on the 18th October 1882.
JOHN CRESSWELL 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 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
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supplied by hand stoking, and the fuel may be stirred or withdrawn when desired

page_text: This opening is closed by a barred frame or grid or a perforated door, and this
frame or grid is enclosed by another door, the grid or perforated frame is hinged on
one side of the opening to the combustion chamber, and the door or cover of the
grid, or perforated frame is hinged on the latter but on the opposite side of the
opening to the combustion chamber.
There is also a lid 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 by two sides in the length way,
connected together by cross bars at intervals, and an upper bar which rests upon
the side bars; this upper bar having projections that pass between the two side bars
and hook upon the cross bars, the upper and lower bars being then secured by a
screw cottur or other means.
There is a space between the upper and lower bar 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 actunted 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.
There is a separate sct of excentrics or cains 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 plate below and between the onds
of the furnace bars and the fire bridge.
The rotating shafts hereinbefore mentioned are geared together by shafts and
worm and worn wheels or in any other convenient manner, the first motion shaft
being driven by a belt or otherwise from any convenient motor.
In some cases my invention consists in using one hopper to supply fuel to two
combustion cliambers in which ease 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 upon the latter.
The slides have movement given to them in the lengthway of the passage but.in.
opposite directions by excentrics or levers or any other convenient mechanism