Improvements in or relating to Mechanical Stokers.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to Mechanical Stokers.
I, THOMAS ANDREWS, of 81 Great Clowes Street, Manchester, in the County
of Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
:-
This invention relates to improvements in mechanical stokers, in which helix
furnace feeders such as are described in the Specification of my Patent
numbered 4904 of 1889, are employed.
The objects of this invention are to simplify the construction of mechanical
stokers and obviate the necessity of displacing the steam and water gauges to
enable either nuts or small coal slack to be used with facility in a self feeding
furnace, and to obtain increased space for the ingress of air under the fire bars.
The accompanying drawing to which I hereinafter refer represents a front view
of part of a two flued boiler with my improvements applied.
In this invention I employ one coal hopper such as a in combination with two
helix feeders for each flue, therefore with a boiler that has two flues, I employ
two coal hoppers, and two pairs of helix feeders, each pair of said feeders working
independently of the other pair.
I construct the aforesaid coal hopper with a triangular shaped bottom as e so as
to cause the coal in its descent to fall in equal proportions on to each of the belix
feeders which are placed equidistant between the centre and the side of the flue
or thereabouts: I construct the shaft d either to extend from side to side of the
boiler and driven from one side only or the driving power may be at each side
of the boiler, and separate shafts employed for carrying the worms № that gear
into the wheels attached to the ends of the aforesaid helix feeders.
:
I communicate the power from pullies e placed on a shaft that carries a pinion g,
said pinion gearing into an internal toothed wheel g¹ of large diameter by which a
preferable speed is obtained.
Any of the aforesaid helix feeders may be detached by withdrawing the clutch
which connects each feeder to a worm wheel that is actuated by a worm as d¹ placed
in proximity thereto on the aforesaid shaft d.
I construct the helical feeding screw with a single web or thread cast on a solid
shaft, the end of the shaft to form a journal and work in bearings so as to prevent
wearing or scraping at the bottom of the case.
The front portion of the screw is preferably formed parallel, tapering towards
the rear end.
The door for access to the ash pit is counterbalanced by a weight sliding on
a rod j.
Dated this 13th day of March 1805
THOMAS PRESCOTT,
53 Arcade Chambers, St. Mary's Gate, Manchester,
Agent for Applicant.

page_text: Improvements in or relating to Mechanical Stokers.
I THOMAS ANDREWS of 81 Great Clowes Street, Manchester, in the County
of Lancaster, Engineer, 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 :-
This invention relates to improvements in mechanical stokers in which helix
furnace feeders such as are described in the Specification of my Patent No. 4904
of 1889 are employed.
The objects of this invention are to simplify the construction of mechanical
stokers, and obviate the necessity of displacing the steam and water gauges : to
enable either nuts or small coal slack to be used with facility in a self feeding
furnace, and to obtain increased space for the ingress of air under the fire bars at
the mouth of the flue.
I attain these objects by the means hereinafter described and as shown in the
accompanying sheet of drawings in which
Fig. 1 is a front view of a two flued boiler with my improvements applied, and
Fig. 2 is a longitudinal section drawn through line A. A. of the front portion of
said boiler with mechanical stoker ;
Fig. 3 is a side view of my improved helical feeding screw.
In these views similar letters refer to similar parts.
In this invention I employ one coal hopper in combination with two helix feeders
for each flue; therefore with a boiler as y that has two flues g' and ' I employ
two coal hoppers as a and a' and two pairs of helix feeders as 6 and 61 each pair of
said feeders working independently of the other pair.
1 construct each of the aforesaid coal hoppers with a triangular shaped bottom
as c so as to cause the coal in its descent to fall in equal proportions on to each of
the helix feeders 6 and each of said helix feeders being placed equi-distant
between the centre and the side of the flue or thereabouts.
The front end of each of the helix feeders 6 and 6 is connected to the back
portion of a clutch j and each of the worm wheels is connected to the front
portion of said clutch. The worms d that gear into the aforesaid wheels / may be
placed either on a shaft that will extend from side to side of the boiler and driven
from one side only, or said worms may be placed on separate shafts as d' and d²
shown on the drawing, and the power communicated through the pulleys e and e¹
and the pinions g and g₁ that are placed respectively on the shafts f and f¹, said
pinions gearing into an internally toothed wheel & fitted on the outer ends of the
shafts d and d. Any of the aforesaid helix feeders may be detached by with-
drawing the clutch; which connects each feeder to a worm wheel that is actuated
by a worm d placed in proximity thereto as hereinbefore described.
I construct the aforesaid helical feeding screw as shown in Fig. 3 with a square
web or thread 63 cast on a solid shaft 65, the ends of the shaft to form journals as 66
and work in bearings so as to prevent wearing or scraping at the bottom of the
screw case ².
The front portion of the screw is preferably formed parallel, tapering towards
the rear end.
The door for access to the furnace is counterbalanced by a weight sliding on a
rod j¹.
Having now particularly described and ascertained the nature of this my said
invention and in what manner the same is to be performed I declare that what I
claim is :-
1st. In mechanical stokers, the combination of two helical feeding screws with

page_text: one coal hopper for each flue in a Lancashire, Cornish, or like boiler, said hopper
being constructed in the manner and for the purpose substantially as hereinbefore
described.
2nd. In mechanical stokers, the use of a helical feeding screw constructed with.
a solid shaft 6 as shown in Fig. 3. on the drawing and as herein before described.
3rd. Mechanical stokers arranged and constructed substantially as herein before
described and driven by means of a pinion or pinions that gear into internally
toothed wheels as k.
Dated this 13th day of January 1896
THOS. PRESCOTT,
53 Arcade Chambers, St. Mary's Gate, Manchester,
Agent for Applicant.