A New or Improved Mechanical Stoker.
Year: 1892

page_text: Date of Application, 24th Nov., 1892-Accepted, 1st July, 1893
COMPLETE SPECIFICATION.
A New or Improved Mechanical Stoker.
I, FRIEDRICH OTTO RUPPERT, of 2 Platanenstrasse, Chemnitz in the Kingdom
of Saxony and German Empire, 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 apparatus for mechanically supplying coal or other fuel
to boiler and other furnaces, and its object is to ensure a regular and even
distribution of the fuel.
One form of the apparatus constructed to embody these improvements is shewn
in the accompanying drawings where :-
Figure 1 illustrates a vertical section of the furnace and the stoking apparatus ;
Figures 2 and 3 represent views at right angles to each other of the mechanism
by which motion is imparted to the distributing shovel; and
Figure 4 shews the form of shovel adapted for use with furnaces or fireboxes,
when the doors are narrower than the grates.
Referring to the drawings, B is a hopper or receptacle containing the fuel which
is to be introduced into the furnace. Next to it and between it and the furnace is
the compartment A containing the feeding roller g and the shovel b. The feeding
roller g is formed or provided with suitable projections preferably in the form of
ribs by means of which the fuel is fed forward upon the rotation of the roller.
The shovel consists of a suitably shaped bar or blade which is attached by means
of the arms to the shaft a. The shape given to the shovel is such as to enable
it to easily lift and carry the fuel.
The fuel hopper or receptacle B is provided with a flat door e which may be
opened to give access to the furnace when it is desired to light the fire or should it
ever be necessary to accomplish the stoking by hand. The compartment A is
similarly furnished with a flap door through which the attendant may remove
cinders or slag. The fire box or furnace to which the apparatus is attached is
indicated at c. It is preferred to mount the whole apparatus upon a frame or
carriage furnished with wheels m.
To prevent the fuel being thrown about unnecessarily, as would happen if the
shovel moved at an even speed, a varying speed of rotation is imparted to the
shaft a, to which the shovel is secured, so that it attains its maximum speed at
the moment the fuel is discharged from the shovel. This varying speed is obtained
by providing the shaft a with a crank t the pin of which, i, slides in a crank h
secured to the driving pulley s or to its shaft R. This shaft R is supported by a
lever k pivoted at S so that the operative length of the crank may be altered by
moving the lever k as desired. An armn is attached to the lever by a moveable socket
as shewn at o by means of which the operative length of the lever k is altered and
of course the crank is influenced. The other end of the arm n is attached to a
disc which serves as a crank wheel with an adjustable pin. The crank thus
formed is also variable within certain limits and has its effect upon the lever k and
the crank. It will thus be seen that when the pulley S or the shaft R is rotated,
that the shovel shaft a is also rotated owing to the engagement of the slotted
crank with the pin of the crank t. The speed of rotation of the crank t and the
shaft a will however be varying, the greatest speed being attained when the cranks
are in the position shewn in Figure 2, when the crank pin i is at its greatest
distance from the centre of the driving shaft R. When the cranks are in their
diametrically opposite positions the speed of the shaft a will be at its minimum as
in this case the pin is at its nearest to the centre of the shaft R and is conse-
quently driven by a very much shorter crank. This variation of the speed of the

page_text: shaft a may be adjusted by moving the shaft R nearer to or farther from a co-axial
position with the shaft u. If the two shafts were co-axial the shaft a would then
revolve at a constant speed, but the farther they were moved from this position the
greater would be the variation in speed in the shaft a. The method illustrated of
adjusting the shaft. R relatively to the shaft a by means of the connecting rod n
and the disc will be found generally convenient, but if desired the disc / may be
connected directly to the lever k in which the shaft R is mounted. As a modi-
fication the lever k and the rod n may occupy the positions shewn in the dotted
lines kn¹. A varying speed is thus imparted to the shovel shaft a by moving the
shaft R, and the fuel is thus thrown to any required distance.
Should the door or entrance to the firebox or furnace be of less width than the
grate, the form of shovel shewn at 6 Figure 1 may be adopted by means of which
the fuel diverges and is distributed over the full width of the furnace.
The operation of the apparatus is as follows:-The fire having been lighted
through the opening e the hopper B is filled with fuel and the feed roller g and the
shaft R are rotated by any suitable means. The fuel passes through the bottom of
the hopper and is fed by the feed roller to the shovel 6 by which it is thrown upon
the furnace. The throw of the shovel is adjusted by moving the slide o on the
lever and by rotating the disc by a hand wheel until the crank is properly
adjusted.
If it is not desirable or convenient to permanently attach the apparatus to the
furnace it may be mounted upon a suitable carriage and be moved into place as
shewn in Figure 1 without the necessity of altering the furnace or boiler.
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
1. In a mechanical stoker the combination with a feed roller of a variable speed
rotating shovel substantially as and for the purpose set forth and as illustrated by
the accompanying drawings.
2. The combination with a mechanical stoker of the apparatus hereinbefore
described for imparting a variable speed to the shovel, constructed and arranged
substantially as and for the purpose set forth and as illustrated by the accompanying
drawings.
3. An apparatus for mechanically delivering fuel to boiler and other furnaces
constructed and arranged substantially as herein before described and as illustrated
by the accompanying drawings.
Dated this 23rd day of November A.D. 1892.
WILLIAM E. HEYS,
Agent for the Applicant.