Improvements in the Manufacture of Compressed Fuel Blocks.
Year: 1889

page_text: Date of Application, 20th July, 1889-Accepted, 24th Aug., 1889
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Compressed Fuel Blocks.
I, WALTER HUBBARD, of No. 1, Linton Road, Hastings, in the County of Sussex,
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 :-
Compressed fuel is usually made by mixing the ordinary waste or slack fuel of
collieries with pitch or tar and compressing the same into blocks. There are several
objections to the use of tar for this purpose. The cost of tar when considered as
a heat producing substance, is large compared with the cost of coal, and the blocks
obtained are liable to become soft and adhere together. Also, in the combustion
of the blocks the tar is the cause of much smoke.
It has also been proposed to use for binding purposes soluble silicates in solution,
such as silicate of soda; and to add lime, cement, clay, or other materials. I find
these additions of lime, cement, clay and other materials to be detrimental, and that
a much more satisfactory result is obtained by the use of silicate of soda or other
soluble silicates alone. By so doing, I am able to keep the amount of the binding
material in the block, below five per cent., whereas, when silicate of soda is used
with lime, cement, clay or other materials, the proportion of binding material varies
from eight per cent. upwards. The advantage is that by keeping the proportion of
binding material low, expense is avoided and also the ash remaining after com-
bustion is less in quantity; moreover the combustion of the blocks is not retarded
so much by the presence of incombustible material.
The special silicate solution which I prefer to use on account of its cheapness and
general efficiency, is composed as follows :-
--
"
in aqueous solution of 75° Tralles.
Both these silicate solutions may contain sulphate of soda not exceeding 2% in
quantity, but no addition of lime, cement, clay, tar, or other material is necessary
or advisable.
•
The waste or slack coal used in the manufacture of compressed fuel blocks may
be with advantage screened and graded into smaller and larger pieces. I find that
by so doing, the blocks become harder and stronger. When adopting this method
I do not confine myself to an exact proportion of fine and coarse particles of coal,
as the sizes of the particles may vary greatly in themselves; but I find generally,
that from one quarter to one third of fine material to two thirds or three quarters of
the coarse material is a good proportion. The fine material may be screened through
a sieve having 32 meshes to the inch, and the coarse through a sieve having one
fourth of an inch mesh.
In the manufacture of the fuel blocks the coal is first moistened with water and
then mixed with from two to five per cent. of silicate solution. It is then moulded
into blocks, compressed, and subsequently dried. Moistening the coal in the first
instance, tends I find, to make the blocks harder and more uniform in structure.
To increase the inflammability and rapidity of combustion of the blocks, I may
soak them in crude mineral oil, or combine them with the residuum thereof.
17

page_text: Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to he performed, I declare that what I
claim is :-
1. The combination of moistened small coal or coal dust with silicate of soda or
other soluble silicates in solution; substantially as and in the proportions described.
2. In the manufacture of compressed fuel blocks, the combination of a special
silicate solution substantially as described, with small coal and coal dust whether
graded or not.
3. In the manufacture of compressed fuel blocks, the use of proportions of graded
fine and coarse small coal or coal dust; substantially as described.
4. In the manufacture of compressed fuel blocks, by the use of silicate of soda or
other silicates in solution and small coal or coal dust whether graded or not the
combination or addition of crude oil or the residuum thereof substantially as
described. .
1 190
WALTER HUBBARD.
By Fairfax & Wetter,
433, Strand, London, Agents for the Applicant.
WALTER HUBBARD.
By Fairfax & Wetter,
433, Strand, London, Agents for the Applicant.