Improvements in Devices for Feeding Fuel to Furnaces in Dust Form.
Year: 1893

page_text: Date of Application, 22nd July, 1893-Accepted, 21st July, 1894
COMPLETE SPECIFICATION.
Improvements in Devices for Feeding Fuel to Furnaces in
Dust Form.
I, AUGUST RIEDINGER, of 23, Eisenhammerstrasse, Augsburg, in the German
Empire, Gentleman, 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 apparatus or devices for supplying
pulverulent fuel to furnaces. Examples of the fuels which may be employed with
such apparatus are:-Coal-dust, saw-dust, coke-dust, and other similar hydro-
carbons. By means of apparatus constructed and operated as hereinafter described,
such fuels may be automatically supplied to furnaces in such a manner as to obtain
uniform results, such for example as a practically constant boiler pressure.
In order that my invention may be fully understood and carried into practical
effect I have appended hereto a sheet of drawings in the various figures of which
similar details of construction are denoted by similar letters of reference.
Figure 1 is a longitudinal section of the apparatus, and
Figure 2 is a plan.
Figure 3 is a plan of the feed wheel, and
Figure 4 a front elevation of the hopper and mixing chamber.
Upon the furnace door a there is fixed a tubular chamber 6 having open ends one
of which communicates through a corresponding opening in the door a with the
furnace. In the upper part of the chamber b there is the inlet c and above it
the funnel e. A ratchet feed wheel d is arranged in the inlet and is rotated by
means hereinafter described at such speeds as may momentarily be required for the
supply of the fuel. The feed pipe fis fixed co-axially above the funnel and inlet,
and has arranged in it the vertical sliding rack in the teeth of which the
pinion gears. This pinion may be rotated by the hand wheel 2. The rack is
carried on a rod which slides in suitable bearings as shewn by Figures 1 and 2 and
to the lower end of the rod there is secured the cone g. By this means there is
provided an annular opening between the lower end of the feed tube and the cone
which may be opened or closed to any desired extent as may be required for
regulating the feed of the fuel which passes through this opening from the feed
pipe to the funnel and inlet.
On any suitable fixing or standard such as there is secured the diaphragm
casing m provided with a steam or blast inlet o, a diaphragm n and a spring m³.
The inlet may be connected by the pipe o' to a source of high pressure steam or
air, according to which it may be determined to use for the purpose hereinafter
described. The front of the diaphragm casing is provided with a tubular outlet m¹
which has arranged within it the cone p' fixed upon one end of the spindle p. This
spindle passes through the centre of the diaphragm to which it is secured by two
fast collars or the like so that motions of the diaphragm must be imparted to the
spindle. The other end of the spindle is guided by and passes through the end of
the spring casing m² where it is jointed to the vertical lever r fulcrumed at q to an
extension from the fixing l.
The diaphragm may be of thin steel concentrically corrugated, and resemble on
a larger scale the similar diaphragms used in Schaeffer pressure gauges and
aneroids.
The upper end of the lever r is pinned to the parallel rods r¹ by the cross rod r³
so that the rods participate in the motion of the lever r. These rods are
connected to the sliding bearings s' on the brackets ss in which bearings is carried

page_text: a spindle on which are fixed the blade wheel and the worm w.
One of the.
brackets s is extended and carries a vertical spindle on which the worm wheel u
gearing with the worm w and the excentric are mounted. The excentric strap.
carries the pawl k which is supported in the slotted bearing i on the upper side of
the chamber b, Figure 4.
When the apparatus is at work the pulverulent fuel is supplied to the feed pipe f,
from which its admission to the funnel e is regulated by the position of the cone g
relatively to the lower end of the feed pipe. Steam or air under pressure is
admitted through o and issues at a high velocity from and through the annular
space between p¹ and m' which are co-axial with the chamber b. The annular jet
of steam or air consequently enters this chamber through which it passes through
the door a to the furnace carrying the fuel fed to it through the inlet c by the feed
wheel d. The feed wheel is intermittently rotated by the pawl k which is
reciprocated by the excentric deriving its motion from the worm wheel u and
worm v, the latter of which derives its motion from the blade wheel t rotated by
the annular jet of steam or air issuing around p', in which its lower portion is
immersed as shewn by Figure 1.
The high pressure steam or air entering the diaphragm casing through o acts
upon the diaphragm by pushing it in the direction tending to compress the spring,
and the amount of this displacement of the diaphragm will be proportional to the
pressure. Since also any displacement of the centre of the diaphragm will
involve a corresponding displacement of the cone p² in the direction of its axis,
and since the spring tends to force the diaphragm centre against the steam pressure,
it follows that with an increase of pressure the annular opening around p₁ and the
outflow of steam or air will be diminished, and with a decrease of pressure they
will be increased. Since also the speed of rotation of the feed wheel d is governed
by the speed of the jet issuing around p¹, the rate of feed of the fuel will be
correspondingly diminished and increased. Hence the supply of fuel will be
automatically controlled and will be altered in its rate inversely to alterations in
the pressure of the steam or air supplied through o. This offers a convenient
arrangement for regulating the supply of fuel to the furnaces of steam generators
in which case a supply of steam through o will be derived from the boiler heated
by the furnace. If air be supplied to the diaphragm casing its pressure may be
regulated by hand or otherwise. If steam be used, the jet induces a sufficient
current of air through the chamber into the furnace to serve all the purposes of
combustion, whilst the velocity of its entrance suffices to keep the fire continually
agitated.
If it be desired to examine the fire, the pipe o' is closed by a cock or valve, and
the furnace door may be opened, there being no physical connection between the
chamber b and its accessories and the other part of the apparatus.
The slotted
bearing of the pawl k, freely permits the movement of the bearing away from the
pawl, which in its turn may be moved to one side out of the way, being centred on
the excentric v.
In order to prevent the extinction of the fire, it may be arranged that the
annular space around p¹ can never be completely closed, so that the jet never
entirely ceases, but should the pressure of steam in the case of a steam boiler
increase beyond safe limits this pressure exerted upon the diaphragm displaces it
and the spindle b and thereby the rods and the sliding bearings s s¹ until the
worm w is drawn out of engagement with the worm wheel u and the feed of fuel is
consequently suspended. When the boiler pressure is reduced, the spring forces
the lever back and the worm again into engagement with the worm wheel,
whereupon the feed is resumed.
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 apparatus for supplying pulverulent fuel to furnaces, the combination and

page_text: arrangement of the chamber 6 the inlet e the feed wheel d the feed tube / and
adjustable cone g, a diaphragm contained in a suitable casing, a cone connected
with the centre of the diaphragm and arranged in the outlet from the casing, a
steam or air inlet, a spindle connecting the casing with the lever r, a spring acting
against the diaphragm, a blade wheel t, a worm wheel excentric and pawl operating
the feed wheel, and rods r', connecting the lever r with the bearings of the worm
and blade wheel spindle, substantially as hereinbefore described and as illustrated
by the accompanying drawings.
2. In apparatus for supplying pulverulent fuel to furnaces, a diaphragm enclosed
in a casing on one side of which high pressure steam or air is admitted and escapes
by an annular jet formed by a cone arranged axially with the diaphragm in an
outlet and connected therewith by a spindle, in combination with a spring tending
to force the diaphragm against the fluid pressure, constructed and arranged
substantially as and for the purpose herein before described and as illustrated by
the accompanying drawings.
3. In apparatus for supplying pulverulent fuel to furnaces, the combination and
arrangement with a fuel feed wheel having ratchet teeth thereon, of a pawl
reciprocated by an excentric and actuating the feed wheel, a worm wheel rotating
with the excentric, a worm gearing with the worm wheel and fixed upon a spindle
which also carries a blade wheel, and a jet of high pressure steam or air operating
the blade wheel, substantially as hereinbefore described and as illustrated by the
accompanying drawings.
4. An apparatus for supplying pulverulent fuel to furnaces, constructed arranged
and automatically operating substantially as herein before described and as
illustrated by the accompanying drawings.
Dated this 21st day of July A.D. 1893.
WILLIAM E. HEYS,
Agent for the Applicant.