IMPROVEMENTS IN THE MANUFACTURE OR PREPARATION OF FUEL.”
Year: 1872

page_text: LETTERS PATENT to Martin Rae, of Uphall, in the County of
Linlithgow, North Britain, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OR PREPARATION OF FUEL.”
PROVISIONAL SPECIFICATION left by the said Martin Rae at the
Office of the Commissioners of Patents, with his Petition, on the
10th June 1872.
I, MARTIN RAE, of Uphall, in the County of Linlithgow, North
Britain, do hereby declare the nature of my said Invention for "IM-
PROVEMENTS IN THE MANUFACTURE OR PREPARATION OF FUEL," to be as
follows:
In carrying out my Invention I take either coal dust, or small coal,
or coal dross reduced to a powder; and after washing it free of aluminous
or earthy matters, dry the same in a furnace, at the end of which furnace
is attaclied a mixing machine, into which the coal dust is passed and
thoroughly mixed with about 15 per cent. of bituminous màstic. The

page_text: "E
mixing machine delivers the composition into a pressing machine, where
it is pressed into blocks, and when cold it is ready for use. Or I take
waste shale from the pits, or after it has passed through the retorts at
the oil works, or bituminous "blac," or coaly blae," which is found in
connection with coal and shale, and reduce it to powder, after which I
add about 50 per cent. of coal dust or powder. To this mixture I add
about 25 per cent. of bituminous mastic, and treat it in the same
manner as already described.
I propose to prepare the bituminous mastic in the following manner :—
I take the crude shale tar obtained in the distillation and refining of
mineral oil from bituminous shale, this tar being a waste product, for
which no useful purpose has hitherto been found. The tar being freed
from sulphuric acid by means of steaming and washing is run into a
still or evaporating pan, where a portion of the light oils and the water
is distilled off, which renders the tar more dense and tenacious. A pipe
connecting the evaporating pan with the mixing machine supplies the
requisite amount of bituminous mastic to the coal dust and the other
mixtures already mentioned.
I propose to combine in one apparatus the furnace for drying and
heating the coal dust, powdered stone, or powdered "blae," the mixing
and pressing machines, the steam boiler, and the engine which turns the
machinery. The furnace may be heated by means of the waste heat
from the boiler flues, and other mixing and pressing machines may be
heated by the waste steam from the engine.
SPECIFICATION in pursuance of the conditions of the Letters Patent, 2
filed by the said Martin Rae in the Great Seal Patent Office on the
10th December 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARTIN
RAE, of Uphall, in the County of Linlithgow, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of June, in the year of our
Lord One thousand eight hundred and seventy-two, in the 35th year of
Her reign, did, for Herself, Her heirs and successors, give and grant
3

page_text: unto me, the said Martin Rae, Her special license that I, the said
Martin Rae, my executors, administrators, and assigns, or such others
as I, the said Martin Rac, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and law-
fully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man,
an Invention for "IMPROVEMENTS IN THE MANUFACTURE OR PREPARATION OF
FUEL," upon the condition (amongst others) that I, the said Martin Rac,
my executors or administrators, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Martin Rae, do hereby declare the
nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say :-
My said Invention has for its object the employment and application
of certain waste and by products resulting from the treatment of the
products obtained in the distillation of shale to the production of
artificial fuel, and of materials suitable for the purposes of heating
for the generating of steam for the production of gas, and for the
manufacture of coke, &c; and consists, first, in obtaining from such
before-mentioned waste or by products what I call a bituminous mastic;
and, second, in the employment of the same in conjunction with coal
or with carbonaceous materials in a fine state of division, for the
purposes and in the manner herein-after indicated.
First. The before-mentioned bituminous mastic may be prepared in
the following manner:-I take the crude shale tar obtained in the
distillation and refining of mineral oil from bituminous shale, such tar
being a waste product for which no useful purpose has hitherto been
found. The tar on being freed from sulphuric acid by means of
steaming and washing in lime water, is then run into a still where
the water and a portion of the oils are distilled off, which process

page_text: renders the tar more dense and tenacious and being in a state betwixt
tar and pitch I call it "bituminous mastic." A pipe from the bottom
of the still conveys the mastic to a pan where the heat is kept up to
about 200° Fahrenheit; from this pan the mixing machine containing
the coal dust, coal powder, and other mixtures herein-after described,
is supplied with the requisite proportion of mastic.
Secondly. I take coal dust which can be obtained at a nominal price
at almost every colliery in the United Kingdom. After washing it free
from aluminous matter it is then dried and heated in a furnace, at the
end of which is attached a mixing machine into which the coal dust
is passed by suitable machinery, and thoroughly mixed with about
fifteen per cent. of the before-mentioned bituminous mastic. The
mixing machine delivers the composition into a pressing machine
where it is pressed into blocks of any required size or weight, and
when cold it is ready for shipment, and can be used for any purpose
to which natural coal is applied, such for example as for the purposes
of heating, and for generating steam, the manufacture of gas, coke, &c.
Thirdly. I take small coals, coal dross, or slack, and grind or crush
it to a coarse powder by suitable machinery, after which I treat it in
the manner before mentioned, and add about the same per centage
of the before-mentioned bituminous mastic as already described in
respect of the natural coal dust.
It should be understood that I do not limit myself to the use of any
particular kind of coal, or small coals, coal dross, or slack, in the
manufacture of fuel; for licating or generating steam I prefer the dross
or slack from anthracite coal; for the purposes of gas making I prefer
the dross or slack from Cannel or Parrot coal; and for making coko
I prefer the dross or slack from bituminous or caking coal. In some
cases it may be of advantage to mix a certain proportion of caking with
non-caking coal dross or slack.
An admixture of coals is now adopted, but in a crude manner, in the
fuel or coals supplied to the British Navy, and is obtained by mixing
about one ton of Welsh or non-caking coal with about one ton of
Newcastle or caking coal, and this mixture is known as Baxter's
mixture.
Fourthly. I take either waste shale from the pits, or the shale after
it has passed through the vortical notarts at the oil works and

page_text: or crush it to a coarse powder. by suitable machinery, after which I add
about fifty per cent. of coal dust, or coal powder to about seventy-five
per cent. of this mixture, I then add about twenty-five per cent. of
the before-mentioned bituminous mastic, and treat the mixture in the
same manner as already described.
"
Fifthly. I take bituminous "blae (or laminated clay), or coaly
"blae" (or laminated clay and coal) which is found in connection
with shale and coal; this on being reduced to coarse powder I mix
with about fifty per cent. of coal dust or coal powder to which I
afterwards add about twenty-five per cent. of bituminous mastic, as
already described.
It should be noted here that the object of the fourth and fifth part
of this Invention is the production of a cheap fuel, and that in localities
where waste shale or bituminous "blae" cannot be obtained, spent tan,
sawdust, or coke breeze may be used as their substitutes.
It should be noted that in the preparation of the bituminous mastic
above stated, the shale tar may be used in conjunction with other tars
or bitumens, as described in a Patent granted to John Pender and
myself, dated December, One thousand eight hundred and seventy-one,
No. 3398; but on economic grounds I prefer to use shale tar alone.
The oils obtained from the shale tar in the preparation of the mastic,
as also the heavy oils obtained from coal tar may be utilized by mixing
them with the coal dust and coal powder, which will be found to absorb
from about five to about seven per cent. of oil, and that "blae," spent
tan, sawdust, and coke breeze will absorb from about ten to about
fifteen per cent. of oil, without rendering the fuel friable.
Sixth. The apparatus for preparing the fuel and converting it into
solid blocks may be similar to the ordinary machines employed in the
production, blocking, or compressing of artificial fuel, or similar to a
brickmaking machine, with this difference, videlicet, that the mixing
mill and the pressing machine should be heated to about 200° Fahrenheit,
and that the fuel is made at this temperature instead of being made in a
cold state like bricks. And in order to economise heat in the preparation
of the fuel the apparatus is combined and connected, the coal dust and
other mixtures being partially dried and heated by the waste heat from
the flues; they are then passed through the furnace by means of endless
chains and scrapers, where they are licated to about 200° Fahrenheit

page_text: before passing into the mixing machine. The mixing and pressing
machines may likewise be heated by the waste steam from the engine.
The annexed Drawing represents in side clevation the general arrange-
ment of the machinery for the manufacture of patent fuel from a mixture
of coal tar and finely ground coal. The tar first undergoes the process
of separation into its constituent parts, those parts useful to the fucl
being mixed with the coal, spent tan, sawdust, or coke breeze during the
process of manufacture, which, will horcin-after be described.
a, a, are steaming vats into which the crude tar is placed to separate
it from the acid contained in it, which is effected by heating the tar by
means of a steam coil a¹ in the bottom of the vat. When the tar is
raised to the proper temperature the acid separates from it and sinks to
the bottom, whence at intervals it runs off by a pipe a" for that purpose
into store tanks situate in the base of the building or in any other
suitable position.
During the process of separating the acid from the tar a small quantity
of oil also contained in the tar evaporates and passes by the pipe b¹ into
the waste oil vats (b, b,) where it is caught and stored. The steaming
vats are made of wood lined with lead, the steam coil is also made of
lead, and the sluice valve 6" of patent metal to resist the corrosive action
of the acid. After the acid has been separated from the tar the sluice
valve or valves are opened, when the tar passes into the distilling vat
or vats, one of which is shown at C, where the tar and oils are separated;
this is accomplished by heating to the proper temperature by means of
a pair of steam coils c, c', one placed above the other, and by surrounding
the cylindrical portion of the vat with a steam jacket. The coils
are fed with steam direct from the boiler; the jackets are heated by
the steam that has passed through the coil, previous to its escaping into
the atmosphere.
When the tar has reached the proper temperature the oil will begin
to evaporate and pass into the condenser, shown in end view at d, and
will continue to do so till the whole of the oil has passed over. The tar
is then run off into the mastic tank (ƒ) and is ready for mixing with the
coal at the required temperature. The oil is condensed by means of the
condenser d, formed by a number of vertical pipes arranged side by side
and connected together in pairs at the top ends, the lower ends are
secured into a long narrow tank having partitions so arranged that the

page_text: oil is made to circulate through the entire length of tubes or pipes if
necessary, whilst it readily allows the condensed oil to fall at any point
and run off into the oil store tank (d) beneath. Water can be passed
over the outside of the condenser tubes if necessary. The coal is thrown
into the hopper (e), which is provided at the bottom with a double set of
fluted rollers e¹, e¹, for crushing the coal to the proper guage; the out-
side rollers are adjustable. After the coal has been reduced to the
proper size it falls into the heater (g), which consists of a strong cast-
iron box, the under side of which is heated by the waste gases from the
boiler flucs. A pair of rollers, one at either end, carry a couple of flat
link chains g¹ provided with scrapers, which extend across the box and
are placed about six inches apart, the top edge standing about one and a
half inches above the bottom of the box. The scrapers propel the finely
ground coal, spent tan, sawdust, or coke breeze, over the heated plates,.
where it is heated to the required temperature. The pipe (H) is con-
nected with the oil tank and feeds the proper quantity of oil to the
extent of about five per cent. of the weight of the fuel manufactured,
and is mixed with it directly it is ground. At the end of the heater is
placed a vertical pug mill or mixer (J) for mixing the oil, tar, and coal.
This machine consists of a strong cylinder, through the centre of which.
passes a wrought-iron shaft provided with a number of spiral knives for
mixing the fuel and forcing it to the shoot and feeders (J'); this machine
is geared to the engine direct. Above the pug mill is placed a cock (k)
having six branches for supplying and distributing the tar, which is
added to the coal at this point to the amount of about ten per cent. of
the weight of the coal. After the coal has been thoroughly mixed it is
forced into the moulds on the fuel press k'. These moulds are made
in sets of three and linked together to form a chain which works over a
pair of octagon drums. The two outside moulds making blocks twelve
inches by six inches, and the inside one six inches by six inches by six
inches. After the moulds have been filled they are passed under the
double-acting ram (L), the down stroke of which presses the fuel to its
proper density and at the same time forces out the blocks from the
moulds immediately under it, the last half of the up stroke giving
motion to the moulds to bring them under the ram, and also propelling
the finished blocks through the drying oven (L'), should it be found
advisable to use an oven. An inclined plane prevents the blocks falling
too rapidly on to the travelling table (M). The travelling table consists
of a couple of flat link chains connected together transversely by small

page_text: round rods, upon which the blocks of fuel rest. The oven is placed
between the boilers and is heated by the gases from the furnaces; after
the heated gases have traversed the length of the boiler once they pass
between the oven plates and then back again under the bottom of the
boiler, whence they pass under the heater to the chimney. The
hydraulic ram on the fuel press is supplied with water from an accumu-
lator, consisting of a strong cast-iron cylinder fitted with a ram loaded to
the required pressure at which the ram works. A small pumping
engine is fixed to the accumulator for keeping it fully charged. The
valve of the press ram is worked by the engine, and is so arranged that
the number of strokes per minute can be varied at pleasure.
Having now described the nature of my said Invention, and having
explained the manner of carrying the same into effect, I would have it
understood that I do not confine myself to the exact proportions or the
precise details herein set forth, as they may require to be varied to suit 1
the character of the materials employed, for example, a lean non-caking
dross will absorb more mastic or oleagenous matter than fat caking
dross, &c., but what I claim as the Invention secured to me by the
herein-before in part recited Letters Patent is,-
First. The preparation of bituminous mastic from shale tar, and the 2
use and application of the same in conjunction with either coal dust,
small coal, coal dross, coal slack, bituminous shale, spent shale, bi-
tuminous "blae," or coaly blac, spent tan, sawdust, and coke breeze,
all by preference in a state of division, or with mixtures of two or more
of the same for the preparation of fuel, as herein set forth.
Second. The peculiar combination and arrangement of machinery or
apparatus for the manufacture of artificial fuel, substantially as herein-
before described, and illustrated by my Drawings.
2
In witness whereof, I, the said Martin Rae, have to this my Specifi-
cation set my hand and seal, the Tenth day of December, One 3
thousand eight hundred and seventy-two.