IMPROVEMENTS IN THE MANUFACTURE OF GAS AND APPARATUS SUITABLE THERETO
Year: 1878

page_text: LETTERS PATENT to Robert Martin, of Bishopric House, Horsham, in the
County of Sussex, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF GAS AND APPARATUS SUITABLE THERETO."
PROVISIONAL SPECIFICATION left by the said Robert Martin at the Office
of the Commissioners of Patents on the 27th May 1878.
"
ROBERT MARTIN, of Bishopric House, Horsham, in the County of Sussex.
PROVEMENTS IN THE MANUFACTURE OF GAS AND APPARATUS SUITABLE THERETO."
IM-
The improvements relate to the retort, to the method of charging, and to mixtures
of coal, or coal and coke, gas tar, tar oil, and other matters, with materials capable
of absorbing their impurities.
I divide the retort into two parts by means of a shelf or slab, placed horizontally,
extending from end to end, and upon each division of such retort I place small coal
or coal and coke dust mixed with powdered clay, chalk, lime, oxide of iron, or other
suitable absorbant material.
I sometimes also form these materials into layers, using first coke dust or cinders,
next small coal, and above these the absorbant material.
I also use gas tar, tar oil, or petroleum mixed with the absorbant material above
named, and combined or not with coke dust or small coal; and I disengage the gas
at a temperature lower than that usually employed.
I charge the retort by means of an apparatus of the same length and breadth as
the interior of the retort, having bars or separations across its length and a sliding
bottom fitted to it. I run this apparatus into the retort, and the contents fall
through on the sliding bottom being removed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Martin in the Great Seal Patent Office on the 21st November
1878.
"IM-
ROBERT MARTIN, of Bishopric House, Horsham, in the County of Sussex.
PROVEMENTS IN THE MANUFACTURE OF GAS AND APPARATUS SUITABLE THERETO."
The improvements relate to the retort, to the method of charging, and to mixtures
of coal, or coal and coke, gas tar, tar oil, and other matters, with materials capable
of absorbing their impurities.
I divide the retort into two parts by means of a shelf or slab, placed horizontally,
extending from end to end; and upon each division of such retort I place small
coal, or coal and coke dust, mixed with powdered clay, chalk, lime, oxide of iron, or
other suitable absorbent materials.
I sometimes also form these materials into layers, using, first, coke dust or cinders,
next, small coal, and above these the absorbent materials.
I also use gas tar, tar oil, or petroleum, mixed with the absorbent materials above
named, and combined or not, with coke dust or small coal; and I disengage the gas
at a temperature lower than that usually employed.
I charge the retort by means of an apparatus of the same length and breadth as
the interior of the retort, having bars or separations across its length and a sliding
bottom fitted to it. I run this apparatus into the retort, and the contents fall
through on the sliding bottom being removed.
The materials used are to be disposed within the retort in layers, oxide of iron,
lime, clay, chalk, loamy earth, or a mixture of these being on the top, or between
them and the exit pipe for the gas; and such oxide of iron, lime, clay, chalk, &c.,
being used for purifying or absorbing the impurities from the gas, I term absorbents
for brevity of description, and sometimes I also mix about 5 per cent. of chalk or
other suitable absorbent with the coal used.
I construct the retort with one or more horizontal shelves, dividing it throughout
its length into two or more spaces, communicating with each other by openings in
such shelf or shelves.
I divide the retort when this is of small dimensions by means of a single shelf
only, but in using large retorts more than one shelf may be employed.
When I use one shelf only, the opening is at the end of the retort furthest from
the exit pipe, in order to allow the gas generated from the materials in the lower
part to pass over and through the heated chambers formed by the upper shelf and
the top of the retort, or I make the shelf slightly shorter than the retort for the
same purpose.
When I use more than one shelf I make the opening in the shelf next the exit
pipe at the end of the retort furthest from that aperture.
When using coal I have found a layer of from 3 to 4 inches in thickness, covered
by a layer in contact with it of about 1/2 to 3/4 of an inch thick, and composed of a
mixture of half loamy clay or earth and half chalk, give good results.
Sometimes I place the layer of coal on the bottom of the retort and the layer of
purifying or absorbent materials on the shelf above, heaping it up to touch the top
of the retort, the gas passing from below through the opening or space at the end
of the shelf, and over and through the absorbent materials on the shelf above.
When using gas tar or petroleum I mix with these as much powdered chalk or
other suitable absorbent as will bring them to a pasty consistency, and cover them
with a layer of clay or earth in contact; or, as when using coal, I place the layer
of clay or earth above them upon the shelf of the retort. Coal may be added to
the mixture of tar or petroleum, and chalk when desired.
Sometimes I construct the retort with a perforated shelf extending throughout
its length and breadth, and I place a layer of gas-producing materials upon the
bottom and a layer of the absorbent materials of any convenient thickness upon
the shelf above, and through which the gas passes to the exit pipe.

page_text: I disengage the gas from the materials at a comparatively low temperature, and
generally apply the greatest heat to the part of the retort the gas passes against or
over immediately before reaching the exit pipe. By this process more gas is
obtained from a given quantity of materials, it leaves the retort much purified, and
little or no tar is generated in its production.
Reference being made to the Drawings,-
Figure 1 shews a retort having a layer of gas-producing materials with a layer
of absorbents above them, placed upon both the bottom of the retort and the shelf
above.
Fig. 2 shews a retort with a layer of gas-producing materials on the bottom and
a layer of absorbents upon the shelf above, with a quantity of the same heaped up
to the top of the retort for the gas to pass through.
Fig. 3 shews a retort with a layer of gas-producing materials on the bottom and
a layer of absorbents upon a perforated shelf above.
Fig. 4 shews a retort with two shelves, the gas-producing materials being on the
bottom of the retort and lower shelf and the absorbents upon the upper shelf.
In the several Figures, a, a, represents the shelves in the retorts; b, b, the exit
pipes; c, c, the layers of gas-producing materials; and d, d, the layers of
absorbents.
Having now described the nature of the said Invention, and the manner in
which the same is to or may be performed, I would have it understood I do not
confine myself to the exact details herein set forth, and I do not claim separately
the mixture of the absorbent or purifying materials above mentioned with the coal
or other gas-producing materials; but what I do claim and intend to be secured
by these Letters Patent is,-
Firstly. Spreading the coal or other gas-producing material within the retort in
a layer or layers with a layer of the absorbent or purifying materials above them,
or between them and the exit pipe, and whether the layers are in contact or not in
contact, substantially as described and illustrated, and for the purposes set forth.
Secondly. The construction of the retort with a shelf or shelves separating it
into two or more horizontal divisions communicating with each other by means of
openings or perforations, substantially as described and illustrated.
Thirdly. The treatment of tar or petroleum for the production of gas as
described.
In witness whereof, I, the said Robert Martin, have hereunto get my hand
and seal, this Twenty-first day of November, in the year of our Lord One
thousand eight hundred and seventy-eight.