IMPROVED APPARATUS FOR GENERATING GAS
Year: 1861

page_text: LETTERS PATENT to Frederick John Evans, of the Chartered Gas Works,
Horseferry Road, Westminster, Gas Engineer, for the Invention of
IMPROVED APPARATUS FOR GENERATING GAS."
Sealed the 3rd December 1861, and dated the 7th October 1861.
PROVISIONAL SPECIFICATION left by the said Frederick John Evans at
the Office of the Commissioners of Patents, with his Petition, on the
7th October 1861.
1, FREDERICK JOHN EVANS, of the Chartered Gas Works, Horseferry Road,
Westminster, Gas Engineer, do hereby declare the nature of the said Inven-
tion for IMPROVED APPARATUS FOR GENERATING GAS," to be as follows:-
14
The object of this Invention is to expedite the manufacture of gas, and
effect an important economy in the manipulation of the process, and the con-
struction of gas-generating apparatus. To this end, instead of using a series
of horizontal retorts, set side by side in a furnace, for generating a given
amount of gas, I propose to construct in lieu thereof a vertical retort of large
capacity, and enclose the same in a furnace, the fire-place of which will be
near the bottom of the retort. The flue leading from the fire-place will rise
spirally around the retort, and have an exit to the chimney near the top of
the retort. I propose to construct the retort of fire-clay, giving it, by prefer-
ence, au oval form in cross section, and making it taper off slightly towards
the top.
The retort will have an opening at top (closed by a drop valve or
CD 1

page_text: plug) for the supply of coal thereto, which may be discharged into the retort
(until it is nearly full) from waggons run up on a level with the top of the
furnace. The lower end of the retort will be bent out of line to bring its
extremity to the outside of the furnace, where it will be fitted with a door
like the ordinary horizontal retorts for closing it air-tight. Through the
bottom of the retort (by the removal of this door) the coke is discharged
when exhausted into suitable receptacles. A pipe leading off from the upper
part of the retort above the furnace conducts the gas as it is generated to the
ordinary condenser. This arrangement of gas-generating apparatus will enable
me when using a suitable coal to effect the discharge of the coke by its own
specific gravity, and thus the labour both of filling and discharging gas retorts
will be materially reduced.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederick John Evans in the Great Seal Patent Office on
the 7th April 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
JOHN EVANS, of the Chartered Gas Works, Horseferry Road, Westminster,
Gas Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of October, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Frederick John Evans, Her special license that I, the said Frederick
John Evans, my executors, administrators, and assigns, or such others as I.
the said Frederick John Evans, my executors, administrators, and 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 lawfully
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
"IMPROVED APPARATUS FOR GENERATING GAS," upon the condition (amongst
others) that. I, the said Frederick John Evans, 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.

page_text: NOW KNOW YE, that I, the said Frederick John Evans, 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 Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
The object of this Invention is to expedite the manufacture of gas, and
effect an important economy both in the manipulation of the process, and in
the construction of the gas-generating apparatus. To this end, instead of.
using, as heretofore, a series of horizontal retorts, set side by side in a furnace,
for generating a given amount of gas, I employ in lieu thereof a vertical retort
of large capacity and of peculiar construction enclosed within a furnace or
oven, and surrounded by a heating flue, which leads from the fire-place and
rises spirally around the retort until it reaches the exit opening to the
chimney.
In the accompanying Drawing, Fig. 1 shews the improved gas-generating
apparatus in vertical section; Fig. 2 is a vertical section, taken at right angles
thereto; Fig. 3 is a top or plan view; and Fig. 4 is a sectional plan, taken
in the line 1, 2, or Figs. 1 and 2.
A, A, is the retort, which may be constructed of fire-clay or of iron, pro-
tected by a a fire-clay covering on its outside, as shewn in the Drawing. This
retort is enclosed in a furnace, and it is made, by preference, of an oval form
in cross section, as shewn at Fig. 4, and corrugated vertically on its inner
surface. A slight taper towards the top is also given to the retort, in order
that it may the better discharge the coke when the illuminating gases are
distilled therefrom. The retort is closed at top with a cast-iron cover C, which
is formed with a valve seat for receiving a drop valve or plug a, and projecting
from the side of the cover is a pipe b, leading to the hydraulic main. The drop
valve a is used for covering the opening by which access is gained to the
interior of the retort for supplying coal thereto, which may be discharged into
the retort(until it is nearly full) from waggons run upon a level with the top of
the furnace. The lower end of the retort inclines downwards, as shewn at
Fig. 1, and extends to the outside of the furnace. It is closed by a door c,
like the ordinary horizontal retorts, and similar means to that ordinarily
adopted are used for securing the door in position, and making it air-tight. A
smallciane mounted in front of the furnace serves to facilitate the operation
of applying and removing the door c; D is the fire-place of the furnace, the
heat from which is caused to circulate by means of a spiral flue E around the
retort and heat it equably. The gases of combustion make their exit near
the top part of the retort into the main flue, and thence to the chimney; e,e,e,

page_text: are sight holes, made in the walls of the furnace to enable the attendant to
observe the degree of heat of the retort, and to give access to the flue for the
purpose of cleaning out the same. The discharge of the coke when the coal
has been carbonized is effected at the outlet f.
The operation of the apparatus is as follows:- A quantity of coke is put
into the retort (it having first been got up to the proper heat), sufficient to fill
the bottom up to a level with the commencement of the vertical sides. Upon
this bed of coke a charge of coal is discharged from a waggon running on
rails fixed over or on a level with the top of the furnace or oven, or by any
other quick and easy method, the drop valve a being first raised from its seat.
When the retort is charged the valve is lowered into its seat, and the heat of
the furnace being kept up the gas will be quickly caused to distil off, and
escape by means of the exit pipe b to the hydraulic main (which may be fixed
in any convenient position), and from thence to the condensers. When the
coal is sufficiently carbonized the door c is withdrawn from the retort, and
swung aside by means of the small crane. The coke is then allowed to run
out of the retort by its own specific gravity, either on to the ground or into
waggons placed ready to receive it; aquantity sufficient to fill the sloping part
or bottom of the retort being, however, retained therein by replacing the lid,
which is then screwed in place and luted as before. The retort is then ready
to receive another charge of coal. Should it be thought desirable, before this
part of the process is performed, steam from a steam boiler may be admitted
into the retort near the bottom. While passing through the red-hot coke it
will be decomposed, and form gases valuable for mixing with the gas pre-
viously distilled from the coal. This decomposition of steam in the retort will
have a two-fold effect; first, it will afford an additional quantity of gas at a
cheap rate; and, secondly, when using coals which swell on being carbonized,
the steam by decomposing or destroying part of the coke will facilitate its
subsequent discharge from the retort. In addition to using steam, any of the
hydrocarbon oils, tar, or such like substances may be economically converted
into gas by injecting them into the bottom part of the retort by any well-
known means. This part of the process may be carried on as long as may be
considered desirable; but as the principal object in view is to make gas from
coal it must only be continued so long as experience may prove it to be pro
fitable so to do; the design of this supplementary distillatory process being to
utilize the heat of the red-hot coke before discharging it from the retort, and
which heat has been obtained in the first instance in converting the coal into
gas by means of the fuel used in the furnace.
Having now set forth the nature of my Invention of" Improved Apparatus

page_text: for Generating Gas," and explained the manner of carrying the same into
effect, I wish it to be understood that under the above in part recited Letters
Patent I claim, the constructing of gas-generating apparatus in the manner
and for the purpose above described.
In witness whereof, I, the said Frederick John Evans, have hereunto.
set my hand and seal, the Seventh day of April, in the year of our
Lord One thousand eight hundred and sixty-two.
F. J. EVANS. (L.S.)