IMPROVED MEANS AND APPARATUS FOR EMPLOYING CHALK AS FUEL
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by John Imray at the Office of
the Commissioners of Patents, with his Petition, on the 12th May
1873. A communication from abroad by Etienne Alfred Luton,
Doctor of Medicine, and Henri Lefèvre, Merchant, both of Rheims,
France.
I, JOHN IMRAY, of No. 20, Southampton Buildings, Ohancery Lane,
in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVED MEANS AND APPARATUS FOR EMPLOYING CHALK AS
FUEL," to be as follows:-
Chalk as is well known is a carbonate of lime softer than other car-
bonates of lime, such as limestone or marble, and its elements can be
separated with greater facility by the application of heat. The carbonic
acid liberated can readily be reduced in presence of carbonaceous matter
by parting with an equivalent of oxygen to carbonic oxide which is
combustible. Farther such moisture as chalk contains becomes decom-
posed at a white heat in presence of carbonaceous matter, yielding
hydrogen or carburets of hydrogen, which forms a fuel of great heating.
value.

page_text: This Invention relates to improved means of utilizing as fuel the
gaseous products from the decomposition of chalk, and to the con-
struction or adaptation of furnaces for that purpose. The moist chalk
may either be fed to a fire in fragments along with fragments of coal, or
be first ground up with the coal, and fuel blocks may be formed
of the mixture. The proportions in either case may vary from 25 parts
of chalk to 100 of coal, up to equal parts of each, or even a larger portion
of the former.
it
may
When the chalk and coal are supplied in fragments without previous
compounding, special furnaces have to be constructed or existing furnaces
have to be adapted for the combustion of the mixed materials.
In constructing or adapting furnaces for this purpose it is important
that they should be made of considerable depth so as to hold a great
thickness of the mixed fuel. Fig. 1 of the accompanying Sheet of
Drawings represents a transverse section of a furnace for a steam boiler
constructed or adapted for burning a mixture of chalk and coal in
fragments. The boiler may be of plain cylindrical form or of the
elephant form A shewn in the Figure. The fire-bars are lowered from
their ordinary level about X, X, to a lower level at C, the sides of the
furnace being made to slope so as to make a wedge-shaped pit, at bottom
of which is a fire-grate of diminished width, with bars more widely
spaced than usual. There are doors P, P, at one end for supplying the
fuel mixture, which doors in case of adapting an existing furnace may be
the ordinary fire-doors. At the opposite end of the furnace another door
is provided at or near the bottom of the furnace for clearing and
removing ash or pieces of cinder or clinker that cannot pass the fire-
bars.
Fig. 2 represents a section of an arrangement of furnace F somewhat
in the form of a lime kiln, having a grate G at bottom and surrounded with
the water of the boiler. Such a furnace may be conveniently fed from
an upper stage or platform by an opening o in the chimney or uptake.
This arrangement besides securing a great depth of combustible and a
considerable and well heated boiler surface is specially adapted for sugar
manufactories where lime kilns are employed, such lime kilns being
replaced by chalk furnaces such as are described above.
Fig. 3 represents in longitudinal section an arrangement of furnace for
burning the mixture of chalk and coal with the fire-grate made in steps.

page_text: A is the body, and B, B, the generator of an elephant boiler, beneath
which is the stepped fire-grate G, G. The mixed fuel is fed by a door P
at one end, and is pushed forwards as it becomes heated so as to occupy
an increasing depth. O is a door for clearing the furnace.
For preparing blocks of the mixed fuel, the chalk and coal are reduced
to a coarse powder, and the mixture is made up into bricks or blocks
which can be burned in any furnace without evolving any appreciable
quantity of smoke or smell.
Instead of coal other combustible carbonaceous materials may be
compounded with the chalk, such as anthracite, peat, pyrites rich in
sulphur, schist, petroleum, naptha, paraffin, asphalte, gas or wood tar,
coke, wood charcoal, greasy or oily matters.
Fuel blocks thus com-
pounded may be used for the production of inflammable gas.