IMPROVEMENTS IN THE MANUFACTURE OF ILLUMINATING GAS AND IN APPA- RATUS FOR THE SAME
Year: 1872

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF ILLUMINATING GAS AND IN APPA-
RATUS FOR THE SAME."-A communication from abroad by François
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 6th April 1872.
I, ALEXANDER Melville Clark, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF ILLUMINATING GAS
AND IN APPARATUS FOR THE SAME," to be as follows:-
This Invention relates to an improved method of manufacturing
illuminating gas from boghead and other coal or hydrocarburets by the
aid of pressure and a superheater, and also to apparatus for the same.

page_text: In distilling coal at a low temperature, that is to say, at from
900 to 1100 degrees Fahrenheit, an olefiant gas is first formed, which
is received in the ordinary way in a vertical tube at the front part of
the retort; secondly, a heavy oil in a vaporized and condensed state is
formed, which deposits on the sides of the retort. By varying the
pressure these vapors and condensed products are collected by the aid
of a perforated tube placed at the upper part of the retort and passed
into a superheater, composed either of two plates of metal placed in
close proximity to one another, or of a series of iron or other metal
tubes of small diameter. This apparatus is either placed in a second
furnace, or by a suitable arrangement of the retorts it may be interposed
between them and the furnace in which they are contained. In this
manner a temperature of from 1500 to 1650 degrees Fahrenheit, may be
readily produced. The vapors and condensed products having already a
tendency to assume a gaseous form on passing between these surfaces
(which are sufficiently close together to prevent the formation of
globular vapor), and thence through a porous body such as charcoal
for example, become transformed into olefiant gas, which is caused to
pass into a separate receiver, and then to the gasometer if a mixed gas
is required, or into a separate gasometer for the richer gas, as the gas
formed by passing the vapors through the superheater possesses a
superior illuminating power to that obtained at the first stage. The
superheating tubes before mentioned are protected by a cast-iron casing.
A saving is obtained by employing pulverized coal placed in a tray or
cupel, the coke obtained being useful for other purposes.
This Invention is illustrated in the accompanying Drawing, Figures
1 and 2 of which show transverse and longitudinal sections of a furnace
with two retorts and superheating tubes common to both. The vapors
on arriving at about the middle of the series of tubes pass right and
left from the retorts into tubes traversing the furnace in which they are
transformed into olefiant gas, which on arriving at the front of the
furnace passes through a vertical tube to a separate receiver as above
mentioned.
The furnace may also be arranged for a larger number of retorts
having separate superheaters for each retort, or for each row of retorts.
This method may be adapted to existing gas manufactories with but
slight modification, it being simply necessary to convey the vapors
and condensed matters to superheaters placed in a separate furnace,

page_text: while by placing a horizontal pipe having perforations along its top
surface at the upper part of the retort, and projecting beyond the furnace,
the gas attained at a low temperature may be collected in the ordinary
way. If only this gas is to be produced the vapors and condensed
matters are shut off from the superheater by a three-way cock, such
condensed matters when collected being employed in the manufacture
of gas on a small scale, as I will now proceed to describe.
By the following method an olefiant gas may be obtained (either
from such condensed matters or from the residues of gas works, or from
hydrocarburets in a more or less purified condition) suited for domestic
and other lighting purposes. The matters to be treated are placed in
a receiver capable of resisting a pressure of several atmospheres, and
subjected to a temperature of from 900 to 1100 degrees Fahrenheit
for the production of vapors, the pressure being indicated on a guage.
In this manner the impure matters will fall to the bottom of the
receiver, and when the guage indicates a certain number of atmospheres,
determined by experience, by opening a cock the vapors are passed in
a superheater similar to that above described, said vapors becoming
converted into gas by reason of the high temperature and small diameter
of the superheater. The gas is then passed to a washing apparatus
or purifier provided with a perforated surface on which is placed lime
or sulphate of iron, and agitated in the alkaline liquid. In this manner
all impurities are separated, supposing impure liquids to have been.
employed, and the gas is then conveyed to a gas holder of sufficient
size for supplying one or more furnaces. Figure 3 of the accompanying
Drawing shows a section of an apparatus adapted to the above purpose.
a, metal retort placed in a suitable furnace y (provided with fire-bars 6¹
and ash-pit c¹), on a plate 6 of fire-clay having apertures c, c. The cover
of the retort is secured to the furnace setting y by clamps d, and is
also provided with an opening e closed in any suitable manner. The
liquids to be converted into gas are introduced at e into the retort
until they reach the level indicated at 1, 2, and the furnace is then
heated either by the aid of coal, coke, gas, or other fuel to from. 900
to 1100 degrees Fahrenheit, or under for the less dense. liquids, and
a pressure in the retort is thus created. The graduated cock f being
closed the pressure is shown on the guage g, and on attaining the
requisite number of atmospheres the impurities in the liquids fall to
the bottom, and on opening cock the vapors pass through tube / to

page_text: the superheater, which in this case simply consists of two tubes similar
to those before described, enclosed in a cast-iron protecting casing z.
The superheater being covered with fuel has a temperature of from 350
to 550 degrees above that of the retort, and the pressure will force the
vapors to pass into the superheating tubes, in contact with which they
become transformed into olefiant gas. Pipe i conveys the gas into the
purifier which is about half filled with a weak alkaline solution,
whence it is conducted to a gasometer by the pipe after passing
through the lime or sulphate of iron on the surface 7.
Instead of introducing a certain quantity of liquid into the apparatus
beforehand, it may be supplied in a continuous manner; and in this
case the apparatus is modified as follows:-The liquid is supplied from
a tank through a pipe m, and is distributed by a rose n, the liquid being
supplied at a higher pressure than that indicated by the guage to prevent
any escape of the vapors through the pipe. The liquid falls in fine jets
on to a porous body, such as charcoal for example, contained in an inner
casing o riveted to the upper part of the retort, and after passing through
the perforated bottom p it comes in contact with the sides of the retort
and becomes transformed into vapors, which are caused to enter the
annular space between the side of the retort and the inner casing o.
This space is made from one to two inches only in width in order to
superheat all the vapors which pass thence by pipe h to the superheater r,
and then through the purifier to the gasometer.
By removing the cover of the retort the interior of the apparatus may
be readily cleaned out after each operation.
By introducing into the apparatus a metallic liquid bath at a suitable
temperature the liquids to be gasified, on being brought in contact
therewith, will be instantly transformed into vapors, which when super-
heated will produce an olefiant gas, such as that produced by either of
the two former methods described, and having an illuminating power
equal to 24 candles.
.
By making the ends of the two superheating tubes project outside the
furnace, and subjecting that portion of the tube within it to a high
temperature, the oils when introduced into the end portion will be suffi
ciently heated (owing to the conductibility of the metal) to become
vaporized, and will be converted into gas on entering that part of the

page_text: superheater, which is directly exposed to the heat of the furnace. The
gas is then purified and conveyed to the gasometer.
I may also introduce water into the retort in lieu of hydrocarburets
and decompose it by introducing under pressure the vapor formed in the
superheater. Then by placing lime and charcoal in the pipe carbonate
of lime is formed, and a portion of the carbon will serve for carburetting
the hydrogen. In this manner a cheap gas suitable for illuminating
purposes may be produced.
In Figures 1 and 2, a, a¹, are the retorts supported on plates b of
fire-clay, which are in turn carried on arches c; d, perforated pipe.
through which the vapors and condensed products are conducted to.
superheater e by pipe f. The superheater is protected by a cast-iron.
casing g, supported on arches h. i, i, covers connecting the several,
superheating tubes, the gas formed in which passes therefrom through,
elbow j and pipe k to a receiver. The head of the retort is arranged
as usual, being provided with a pipe m for conducting the gases first.
generated to a receiver, the pressure in which is greater than that in the
other. n, brick furnace setting. The furnace gases after having heated,
the superheater escape at o and thence proceed to heat the retort, finally
passing through flues p to the chimney; q, damper for regulating the
draft; the fire-bars r, ashpit 8, and plate t, are arranged as usual; u, cock,
for turning the vapors into condenser v when the gas obtained at the,
first stage only is to be produced, the condensed products being drawn.
off by a cock; x, tray, on which the pulverized boghead or other coal:
is introduced into the retort.
:
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent'
Office on the 4th October 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
'
}
WHEREAS Her most Excellent. Majesty Queen Victoria, by Her.
Letters Patent, bearing date the Sixth day of April, in the year,
of our Lord One thousand eight hundred and seventy-two, in tho

page_text: to pass into a superheater composed either of two plates of metal placed,
in close proximity to one another, or of a series of iron or other metal
tubes of small diameter. This apparatus is either placed in a second
furnace, or by a suitable arrangement of the retorts it may be interposed;
between them and the furnace in which they are contained. In this
manner a temperatue of from 1500 to 1650 degrees Fahrenheit may be
readily produced, and as the said vaporized and condensed products have.
already a tendency to assume a gaseous form, they will on passing
between the surfaces of the superheater (which are sufficiently close
together to prevent the formation of globular vapor) and thence through,
a porous body, such as charcoal for example, become transformed into;
olefiant gas which may be caused to pass into a separate receiver, and.
then to the gasometer if a mixed gas is required, or into a separate,
gasometer for the richer gas, the gas formed by passing the vapors;
through the superheater possessing a superior illuminating power to.
that obtained at the first stage. The superheating tubes before.
mentioned are protected by a cast-iron casing. A saving is obtained,
by employing pulverized coal placed in a tray or cupel, the coke
obtained being useful for other purposes.
This Invention is illustrated in the accompanying Drawing, Figures 1'
and 2 of which show transverse and longitudinal sections of a furnace
with two retorts and superheating tubes common to both. a, a¹, are'
the retorts supported on plates 6 of fire-clay, which are in turn carried
on arches c; d, perforated pipe through which the vaporized and con-.
densed products are conducted to superheater e by pipe f. The super-
heater is protected by a cast-iron casing ġ supported on arches h.
i, i, covers connecting the several superheating tubes, the gas formed-
in which passes therefrom through elbow j and pipe k to a receiver.'
The head of the retort is arranged as usual, being provided with a
pipe m for conducting the gases first generated to a receiver, the
pressure in which is greater than that in the other. n brick furnace
setting. The furnace gases after having heated the superheater escape
at o and thence proceed to heat the retort, finally passing through
flues to the chimney. q, damper for regulating the draft, the fire.
bars r, ash-pit 8, and plate t, are arranged as usual. u, cock for turning;
the vapors into condenser v when the gas produced at the first stage.
only is to be obtained, the condensed products being drawn off by a
cock. x, tray on which the pulverized boghead or other coal is intro-;

page_text: duced into the retort. The vapors on arriving from the retorts by
pipe pass right and left into the superheating tubes e, traversing the
furnace in which they are transformed into olefiant gas, which on
arriving at the front of the furnace passes through the vertical tube k
to a separate receiver, as above mentioned.
The furnace may also be arranged for a larger number of retorts
having separate superheaters for each retort or for each row of retorts.
This method may be adapted to existing gas manufactories with but
slight modification, it being simply necessary to convey the vaporized
and condensed matters to superheaters placed in a separate furnace,
while by placing a horizontal pipe having perforations along its top
surface at the upper part of the retort, and projecting beyond the furnace,
the gas obtained at a low temperature may be collected in the ordinary
way. If only this gas is to be produced the vapors and condensed
matters are shut off from the superheater by a three-way cock, such
condensed matters when collected being employed in the manufacture of
gas on a small scale, as I will now proceed to describe.
By the following method an olefiant gas may be obtained (either from
such condensed matters or from the residues of gasworks, or from hydro-
carburets in a more or less purified condition) suited for domestic and
other lighting purposes. The matters to be treated are placed in a
receiver capable of resisting a pressure of several atmospheres, and sub-
jected to a temperature of from 900 to 1100 degrees Fahrenheit for the
production of vapors, the pressure being indicated on a guage. In this
manner the impure matters will be caused to fall to the bottom of the
receiver, and when the guage indicates a certain number of atmospheres
determined by experience, the vapors are passed through a cock into a
superheater similar to that above described, said vapors becoming con-
verted into gas by the high temperature and small diameter of the
superheater. The gas is then passed to a washing apparatus or purifier
provided with a perforated surface, on which is placed lime or sulphate
of iron, and agitated in the alkaline liquid. In this manner all im-
purities are separated, supposing impure liquids to have been employed,
and the gas is then conveyed to a gas holder of sufficient size for sup-
plying one or more furnaces.
Figure 3 of the accompanying Drawing shows a section of an
apparatus adapted to the above purpose. a, metal retort placed in a

page_text: suitable furnace y (provided with fire-bars and ash-pit c¹) on a
plate of fire-clay having apertures c, c. The cover of the retort is
secured to the furnace setting y by clamps d, and is also provided with
an opening e closed in any suitable manner. The liquids to be con-
verted into gas are introduced at e into the retorts until they reach the
level indicated at 1, 2, and the furnace is then heated either by the aid
of coal, coke, gas, or other fuel to from 900 to 1100 degrees Fahrenheit,
or under for the less dense liquids, and a pressure in the retort is thus
created. The graduated cock f being closed the pressure is shown on
the guage g, and on attaining the requisite number of atmospheres the
impurities in the liquids fall to the bottom, and on opening cock f the
vapors pass through tube h to the superheater, which in this case simply
consists of two tubes similar to those before described enclosed in a cast-
iron protecting casing z. The superheater being covered with fuel has
a temperature of from 350 to 550 degrees above that of the retort, and
the pressure will force the vapors to pass into the superheating tubes, in
contact with which they become transformed into olefiant gas. Pipe i
conveys the gas into the purifier j, which is about half filled with a
weak alkaline solution, whence it is conducted to a gasometer by the
pipe after passing through the lime or sulphate of iron on the
surface l.
Instead of introducing a certain quantity of liquid into the apparatus
beforehand, it may be supplied in a continuous manner; and in this case
the apparatus is modified as follows:-The liquid is supplied from a tank
through a pipe m, and is distributed by a rose n, the liquid being supplied
at a higher pressure than that indicated by the guage to prevent any
escape of the vapors through the pipe. The liquid falls in fine jets on to
a porous body, such as charcoal for example, contained in an inner
casing o riveted to the upper part of the retort, and after passing through
the perforated bottom p, it comes in contact with the sides of the retort
and becomes transformed into vapors which are caused to enter the
annular space between the side of the retort and the inner casing o.
This space is made from one to two inches only in width in order to
superheat all the vapors which pass thence by pipe h to the super-
heater r, and then through the purifier to the gasometer.
By removing the cover of the retort the interior of the apparatus may

page_text: By introducing into the apparatus a metallic liquid bath at a suitable
temperature, the liquids to be gasified on being brought in contact
therewith will be instantly transformed into vapors, which, when super-
heated will produce an olefiant gas, such as that produced by either of
the two former methods described, and having an illuminating power
equal to 24 candles.
By making the ends of the two superheating tubes project outside the
furnace, and subjecting that portion of the tube within it to a high
temperature. The oils when introduced into the end portion will be
sufficiently heated (owing to the conductibility of the metal) to become
vaporized, and will be converted into gas on passing through that part
of the superheater which is directly exposed to the heat of the furnace,
The gas is then purified and conveyed to the gasometer.
I may also introduce water into the retort in lieu of hydro-carburets,
and decompose it by introducing under pressure the vapor formed in
the superheater. Then by placing lime and charcoal in the pipe car-
bonate of lime is formed, and a portion of the carbon will serve for
carburetting the hydrogen. In this manner a cheap gas suitable
for illuminating purposes may be produced.
Having described the nature of the Invention, and in what manner the
same is to be performed, I declare that what I claim as the Invention to
be protected by the herein-before in part recited Letters Patent is,-
-
1st. The manufacture of illuminating gas from hydro-carburets by
first producing vapors under pressure, and then passing them through
a superheater for conversion into olefiant gas, all as herein-before
described.
2ndly. The manufacture of illuminating gas by distilling pulverized
coal or boghead at certain temperatures for producing in the first place,
ordinary gas which is collected in the usual way, and vaporized and con-
densed products which are passed through a superheater containing some
porous material for the purpose of converting the same into olefiant gas
of richer quality, as herein-before described.
3rdly. The arrangements of apparatus illustrated in the accompanying
Drawings, consisting of furnaces having retorts for the distillation of the
coal, and superheaters either combined with the apparatus or separate a

page_text: therefrom, as also the small apparatus for treating hydro-carburets by
first converting the same into vapors and then into gas by the aid of a
superheater, substantially as described.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Fourth day of October,
in the year of our Lord One thousand eight hundred and
seventy-two.