Improvements in and in connection with Furnaces, and Means for Supplying Coal Dust thereto.
Year: 1894

page_text: Date of Application, 12th Nov., 1894-Accepted, 9th Feb., 1895
COMPLETE SPECIFICATION.
Improvements in and in connection with Furnaces, and Means for
Supplying Coal Dust thereto.
I, FERDINAND DE CAMP, Engineer, of Berlin N., Müllerstrasse 170-171, in
the Empire of Germany, 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 :-
My invention relates to furnaces heated with coal dust and the object of my
invention is an apparatus by means of which coal dust can be used as fuel for
heating steam boilers etc.
The apparatuses for this purpose hitherto in use are disadvantageous in con-
sequence of their complicated and clumsy construction, they are therefore expensive
troublesome and unreliable.
In the present invention I use a fan which draws or sucks the coal dust which
is fed up to it by a conical worm, through a revolving sieve and then blows it
through a delivery pipe into the fire box of the boiler.
At the mouth of the
delivery pipe there is contrivance for distributing and regulating the supply of
coal dust by which means the size of the flame can be regulated. Such a feeding
apparatus can also be used for several boilers and fire boxes, in which case other
pipes branch off from the main, and each of them is provided with a throttle-
valve, or a damper etc. to partially or entirely close it off from the main.
I will explain my invention with reference to the accompanying drawings in
which:
Fig. 1 shows the whole arrangement inside view.
Fig. 2 a front view.
Fig. 3 the feeding of the coal dust from the hopper to the fan,-
,-on an enlarged
scale.
Fig. 4 shows a section of a part of the fire-box with the nozzle of the delivery
pipe fixed to the furnace-bed and the flame regulator.
Figs 5, 6 and 7 show details of the appliances for regulating and distributing
the coal dust as it enters the fire-box.
In Figures 1, 2 3 the ventilator is marked A to which is attached the socket B.
In this socket B, and immediately under an upper aperture C there is a revolving
sieve D keyed on to the shaft E and driven by the pulley F. The sieve D is open
at both ends and serves to retain any larger particles of coal. Above the socket B
of the fan A there is a charging funnel H on the bottom of which is placed a
worm, part of which is cylindrical and the other part conical, this worm is rotated
by the pulley K. In the funnel H a throttle M is moveably attached to the
hinge L. Throttle M can be inclined at any angle from the vertical by means of
a regulating screw N which is turned by a hand-wheel, by which means the
opening leading into the worm cau be regulated at will. A damper or slide may
be used instead of a throttle valve. By using a conical worm the choking up same
is prevented, as the coal dust which falls into the front and narrow part of the
worm gradually passes into the worm channel which continually increases in
width. The coal dust passes from the worm through a channel O to the revolving
sieve D.
From this part the coal dust is drawn by the blast which is sucked from the
outer air by the fan A through the sieve D, and forced into the delivery pipe I.
This mixture of air and coal dust is thus blown through the delivery pipe P into
the fire box of the boiler R. (Fig. 4). The delivery pipe P is screwed into the
furnace bed T of the fire box Q. The furnace bed T has a lower door S, through

page_text: which the slag which is formed in the fire box can be withdrawn and through
which the fire can be observed. I line the fire box preferably with fire tiles U.
The mouth of the delivery pipe P is closed by a perforated disc V; on this disc
lies a second perforated disc W which can be rotated by a spindle H from the
outside. The holes in the disc W are drilled in conformity with the holes in
disc V, so that when W is rotated the holes in V can be partially or entirely
closed. By these means coal dust from the delivery pipe is blown into the fire box
like spray. The disc W can be turned in relation to V, so far that no coal dust
can pass through.
Fig. 6 shows a modification of the means of regulating the flame.
In this case
I use a full disc Y in place of the two discs V and W,-this full disc has a somewhat
smaller diameter than the mouth of the conical delivery pipe P so that an annular
aperture is formed for the passage of the coal dust. In proportion as the disc Y is
pushed into the pipe or withdrawn from same by means of the spindle X from the
outside, the flame cone thus formed will be narrow or broad.
Fig. 7 shows a spiral Z placed in the mouth of the delivery pipe P this will
give the mixture of coal dust and air which passes through a whirling motion.
Having now particularly described and ascertained the nature of my said
invention and the manner in which the same is to be performed, I declare that
what I claim is :-
Claim 1. A method of heating furnaces by means of coal dust in which a fan (A)
sucks air through a revolving sieve (D) and with it coal dust which it receives
from a worm I which is partly cylindrical and partly conical, the worm being fed
with coal dust by the feed funnel (H), the thus formed mixture of coal dust and air
being forced by the fan through the delivery pipe (P) into the fire-box (Q) as
duly set forth.
Claim 2. In combination with the use of coal dust as fuel as set forth in Claim 1,
an apparatus for regulating the flaine thus formed, consisting of a fixed perforated
disc (V) placed in the delivery pipe (P) and of a second perforated disc (W)
which can be rotated from without placed against and in front of disc (V) by
means of which by altering the relative position of the perforations by rotating the
disc (W), a larger or smaller flame can be produced at will substantially as
described.
Claim 3. In the flame regulation described in Claim 2 a modification in such
manner that in place of the two said discs, one full disc (Y) is used which is
smaller than the diameter of the delivery pipe (P) and which can be pushed into
said pipe, more or less, and thus produce a narrower or broader hollow flame cone
in the firebox substantially as described.
Claim 4. In the use of coal dust as fuel as set forth in Claim 1, the employment
of the spiral (Z) in the mouth of the delivery pipe (P) for the purpose of imparting
a whirling motion to the mixture issuing from same as duly set forth.
Dated this 12th day of November 1894.
J. E. EVANS-JACKSON & Co.,
Agents for the Applicant.