IMPROVEMENTS IN THE MANUFACTURE OR TREATMENT OF ILLUMINATING GAS AND IN THE APPARATUS EMPLOYED THEREFOR, THE SAID APPARATUS BEING ALSO APPLICABLE FOR THE TREATMENT OF GASES OTHER THAN ILLUMINATING GASES
Year: 1878

page_text: ⠀ LETTERS ·PATENT to: William Young, of Clippens, in the County of Renfrew,
-North Britain; for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OR
TREATMENT OF ILLUMINATING GAS AND
IN THE APPARATUS EMPLOYED
THEREFOR, THE SAID APPARATUS BEING ALSO APPLICABLE FOR THE TREATMENT
OF GASES OTHER THAN ILLUMINATING GASES."
Sealed the 30th July 1878, and dated the 8th February 1878.
"
PROVISIONAL SPECIFICATION left by the said William Young at the
Office of the Commissioners of Patents on the 8th February 1878.
WILLIAM YOUNG, of Clippens, in the County of Renfrew, North Britain.
IMPROVEMENTS IN THE MANUFACTURE OR, TREATMENT OF ILLUMINATING GAS AND
IN THE APPARATUS EMPLOYED THEREFOR, THE SAID APPARATUS BEING ALSO
APPLICABLE FOR THE TREATMENT OF GASES OTHER THAN ILLUMINATING GASES."
1[
It is now a well ascertained fact that the pulsatory movement of the products of
distillation inside the retort, caused by the gases bubbling through the hydraulic
seal, produces an extra deposit of carbon on the internal surface of the walls of the
retort, and that when the gas-producing material is poor, or the temperature of the
retorts high, even with a rich gas-producing material, there is in consequence of this
pulsatory action a. considerable deterioration of the illuminating power of the
resulting gases due to the over decompositon of some of the volatile hydrocarbons
and other highly light-giving gaseous compounds.
Experience has also shown that although the temperature of the crude gases as
they leave the stand pipe and enter the hydraulic is far below, the volatilising point
of the great bulk of the liquid tarry products, yet at this point they are not
precipitated from the crude gases, but are carried forward in a finely divided state
along with solid sooty, matter into the condensers and scrubber and other parts of
the manufacturing plant, where from their absorbent action upon the illuminants
they deteriorate the illuminating power of the gas, and also. by clogging or closing
rn... 077

page_text: the pores of the purifiying material or the interstices in the scrubber they prevent
their proper action.
This Invention has for its principal object improvements in apparatus, whereby
this pulsation of the products inside the retorts is prevented, and a precipitation
effected of the sooty and condensed finely divided liquid matters.
The improved apparatus consists of a valve arrangement actuated by the pressure
of the gas being substituted for the ordinary hydraulic seal or dip pipe.
The valve may partake of a variety of forms, but must be of such a structure as to
divide the gas into a minute stream or sheet issuing under a pressure equal to at
least a column of water of preferably not less than four-tenths of an inch in height,
and as the sooty and pitchy tarry matters are liable to clog or close the orifices of
the valve it must be of such a construction as shall either clean itself or otherwise
adjust the size of the passage or passages as they become closed. The valve is
also provided with a margin or plate placed opposite the edges of the valve, against
which the issuing stream or sheet of gas is made to flow.
A very efficient form of valve consists of a concave or mushroom-shaped sheet of
metal turned perfectly true round its edges, and fixed upon a central spindle or
guide rod; this valve or cover resting upon a seat, also turned perfectly smooth,
and having a central hole or guide for the valve spindle, and a margin slightly larger
than the mushroom-shaped valve cover. This valve arrangement may be con-
veniently fixed in a chamber or pipe attached to the ordinary dip pipe immediately
before it enters the hydraulic, a separate pipe being carried from the chamber over
the valve into the hydraulic above the water line.
The action of the valve is as follows:-The products of destructive distillation
(gas, tar, soot, water, vapour, and other products) issuing from the retort pass along
the stand pipe, and press against the bottom of the concave valve and the
water in the dip pipe; but as the valve cover is lighter than the column of
water to be displaced in the dip pipe it is lifted, and the crude gases and
tars escape in a thin stream or sheet through the valve and flow against the
margin or ledging referred to. The sooty and tarry matters are thereby pre-
cipitated, and the cleansed gases pass by the supplementary pipe to the hydraulic.
As the valve lifts steadily, and is prevented from jumping by stops placed on the
valve chamber cover, all pulsation is prevented, and so soon as gas ceases to be
made the valve falls, and thus automatically prevents the return of the gas into
the retort.
In cases where the crude gases contain a very large quantity of sooty matter
and a small quantity of tars it may happen that these are not wholly removed by
passing through a single valve arrangement. In such a case duplicate valves may
be employed, or (which is preferred) a series of valves may be placed on the outlet
for crude gases from the hydraulic main.
Many other forms of valves may be employed, such as, instead of making the
concave valve cover with a single edge turned quite true, it may consist of a
number of concentric edges fitting into truly turned concentric recesses; or it may
partake of the form of a sluice valve actuated by a gas holder; but the one just
described will it is believed be found the most practically useful.
.
Apparatus of the kind herein-before described may be also used for the treatment
of other gases holding in suspension solid and vapourous matters, such as the gases
from blast furnaces, coke ovens, "Siemens" and other gas furnaces, a fan or other
device being employed to draw or drive the gases through the valves.
In the case of gases which do not contain sufficient tarry or other fluid matters
to entangle and wash away the suspended finely divided dust or sooty matters as
they are precipitated, fluids of a suitable character, such as water for ordinary dry
dust, or oils, either mineral or vegetable, for sooty dust or pitchy tars, may be
showered over the valve cover.
Another purpose to which these valves may with advantage be applied is the
eliminating of ammonia from gases, and for purifying of illuminating gases from
.. carbonic acid and sulphuretted compounds by means of liquid purifying agents.
.

page_text: When used for such purposes the valves are set in a series of chambers over each
other, and the absorbent liquid made to flow successively over each valve cover by.
pipes communicating from chamber to chamber. The liquid absorbent as it reaches
the edges of the cover is violently commingled with the escaping sheet or stream of
gas, and thus a very perfect absorption is brought about.
Another part of this Invention relates to improvements in the manufacture of
illuminating gas, the objects being to produce a gas of high illuminating power,
freedom from sulphur compounds, and non-liability to deposit crystalline naptha in
the main and branch pipes during distribution.
This part of the Invention consists in carbonizing the gas-producing inaterials in
separate retorts at temperatures which will produce the greatest volume of gas in
the one case and of illuminating constituants in the other.
Should the gas-
producing materials be of different qualities, one being more bituminous than the
other, the poorer material is distilled at a very high temperature so as to liberate
as far as possible the hydrogen of its constitution in the gaseous form, either
combined as carburetted hydrogen or free hydrogen, the other or more bituminous
substance is carbonised at a comparatively low temperature, little or over dull
redness, say, a temperature of from 900° to 1300° Fahrenheit.
In the event of the gas-producing materials being of one quality a proportion of
each is distilled separately at different temperatures in the manner just described. .
The poor gases (or those produced at high temperatures) are freed from their
suspended tarry and sooty matter by preference by means of the apparatus previously
described, and are then passed through or mingled with the rich gases (or those
produced at low temperatures) whilst warm, preference being given to passing the
prepared poor gases through the material undergoing carbonization for the production
of the rich gas in the manner explained in the Patent granted to the present
applicant as of the 29th March 1877, No. 1246.
The mingled gases are in turn subjected to condensation, the liquid matters being
(by preference) precipitated by means of the apparatus herein-before described, and
are thereafter subjected to the usual purifying process and passed to the gas holder.
When the tarry oils resulting from the distillation of the gas-producing material
would be of small commercial value they may be with advantage run back into the
retort and subjected to further destructive distillation. Should the temperature at
which the poor gas is produced be so high as to decompose nearly all the liquid
tarry hydrocarbon, and leave a large quantity of sooty matter, the liquid oily tars
produced from the low heated retorts are employed to wash the poor gases either by
running the tars into the hydraulic, or over the valve apparatus, or down the stand
pipes into the retort.
By conducting the manufacture of gas in this manner a gas of high illuminating
power is produced. The sulphur hydrocarbon compounds which are necesarily
present in the poor gas made at high temperatures are in the manner well known
by the re-heating of the gas in the low-heated retorts converted in great part into
sulphuretted hydrogen and deposited carbon, the sulphuretted hydrogen being easily
removed by the ordinary process of purification, and a gas free from sulphur is
produced.
When the poor gas has been produced from common coal it will contain con-
iderable quantities of napthaline; the carburetting of the poor gases by the
ydrocarbons produced at low temperatures prevents the precipitation of this
naterial.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Young in the Great Seal Patent Office on the 8th August
1878.
WILLIAM YOUNG, of Clippens, in the County of Renfrew, North Britain.
"İMPROVEMENTS IN THE MANUFACTURE OR TREATMENT OF ILLUMINATING GAS AND
IN THE APPARATUS EMPLOYED THEREFOR, THE SAID APPARATUS BEING ALSO
APPLICABLE FOR THE TREATMENT OF GASES OTHER THAN ILLUMINATING GASES."
It is now a well ascertained fact that the pulsatory movement of the products of
distillation inside the retort caused by the gases bubbling through the hydraulic
seal, produces an extra deposit of carbon on the internal surface of the walls of the
retort. When the gas-producing material is poor, or when the temperature of the
retorts is high (even when a rich gas-producing material is being distilled), there is
in consequence of this pulsatory action also a considerable deterioration of the
illuminating power of the resulting gases due to the over decomposition of some of
the volatile hydrocarbons, and other highly light-giving gaseous compounds.
Experience has shown that although the temperature of the crude gases as they
leave the stand pipe and enter the hydraulic main is far below the temperature at
which the great bulk of the liquid tarry products volatilizes, yet at this point they
are not precipitated from the crude gases, but are carried forward in a finely divided
state and together with solid sooty matter into the condensers and scrubber and
other parts of the manufacturing plant, where from their absorbent action upon
the illuminants they deteriorate the illuminating power of the gas, and also by
clogging or closing the pores of the purifying material or the interstices in the
scrubber they prevent the proper action thereof.
My said Invention has for its principal object so to improve the apparatus that
this pulsation of the products inside the retorts is prevented or reduced to a minimum,
and a precipitation of the sooty and condensed finely divided liquid matters is effected.
The improved apparatus consists of a valve arrangement actuated by the pressure
of the gas, being substituted for or used in addition to the ordinary hydraulic seal
or dip pipe.
This valve may partake of a variety of forms provided that it is of such a
structure as to cause the division of the gas into a thin stream or sheet issuing
through the valve under a pressure equal to at least a column of water of preferably
not less than four-tenths of an inch in height, and as the sooty and pitchy or tarry
matters are liable to clog and close the orifices of the valve, it should be of such a
construction as will admit of its being readily cleaned, either by its own action or
otherwise, so as to keep the passage or passages clear. The valve is also provided
with a margin or plate placed opposite the edges of the valve, against which the
issuing stream or sheet of gas is made to impinge.
And in order that my said Invention may be properly understood I now proceed
more particularly to set forth the system, mode, or manner in or under which the
same is or may be used or practically carried into effect, reference being had to the
annexed Sheet of Drawings and to the letters and figures marked thereon, that is
to say:-
In Figure 1 is represented a vertical section of a portion of the stand pipe
(marked A), dip pipe (marked B), and hydraulic main (marked C), of a gas-pro-
ducing plant, with which is combined a valve according to my Invention. The
said valve is contained in a valve chamber upon a short pipe D attached to the dip
pipe B. A separate pipe E is carried from the valve chamber above the valve down
into the hydraulic main above the line of the liquid therein, the said pipe being
furnished with a stop-cock E. The valve chamber and valve are shewn separately
and drawn to a larger scale in Figures 2 and 3; Figure 2 being a vertical section,
and Figure 3 a section of the valve chamber shewing the valve in elevation. The
valve is marked F; it is of a concave or mushroom shape, and is turned perfectly

page_text: true around its edge and is fixed upon a central spindle or guide rod f working in a
guide e. The valve F rests upon a seating d formed in the valve chamber, which
seating is likewise turned perfectly true. Around the valve seating d and at a
short distance therefrom is a concentric ring or short tube G, extending above the
valve opening and having therein perforations g below the level of the valve
opening; on the valve chamber cover is fixed or formed a stop b, which prevents
the valve F from rising to above the level of the top of the surrounding ring G.
The action of the valve is as follows:-The products of destructive distillation
(gas, tar, soot, water, vapour, and other products) issuing from the retort pass
along the stand pipe A, and press against the bottom of the valve F and the water
in the dip pipe, but as the said valve does not offer such a resistance to the passage
of the gases as does the column of liquid in the dip pipe the said valve is lifted,
when the crude gases and tars escape in a thin stream or sheet over the valve
seat and flow against the concentric ring G. The sooty and tarry matters are
thereby precipitated, and the cleansed gases, as well as the precipitated tars, pass
through the openings g and down by the supplementary pipe E to the hydraulic
main C.
"
As the valve lifts steadily, and is prevented from jumping by the stops b, the
pulsation herein-before referred to is prevented, or practically so, and so soon as
gas ceases to be made the valve falls, and thus automatically prevents the return of
the gas into the retort.
In the event of the valve F sticking, or its action being otherwise interfered
with, the stop-cock E' on the pipe E may be closed, thereby enabling the cover of
the valve chamber D to be removed to give access to the valve.
Figure 4 represents a vertical section of a portion of a gas-making apparatus,
shewing the valve arrangement as applied to the top of the stand pipe A, so that
the gases from the retort will pass through it to the dip pipe C and hydraulic
main D. The valve arrangement, which is illustrated in this connection, is shewn
separately in vertical section in Figure 5. The valve H is attached to a spindle /
working in a guide h¹ formed in the valve casing I. The said valve is furnished
with an annular rim h², which is turned perfectly true, and rests upon a seating i
also perfectly true. Figure 6 is a plan of the valve H separately. It is furnished
with a number of tongue pieces h³, which project beyond its periphery. Sur-
rounding the valve and fixed in the valve chamber is a ring or short tube J. of an
internal diameter equal to the external diameter of the valve H. In this tube
slots j are formed and fixed in the valve chamber opposite each of these slots j,
and at but a short distance therefrom are rods k. The tongues h³ of the valve H
pass through the slots j and bear against these rods.
The crude gases will cause the valve to rise, and will pass through the slots j in
thin streams, and impinging against the rods k will deposit their tarry and sooty
matters, the cleansed gases, together with the tarry and sooty matters, passing by.
the branch pipe A¹ to the hydraulic main, at which point the tars are drawn off,
the gases passing to the condensers and purifiers in the ordinary manner.
The tongue pieces ³ will, in rising and falling, effect the clearing of the slots
from deposit, which would tend to clog them.
A modification of this valve is represented in vertical section in Figure 7, and in
horizontal section (on the line 1, 2, Figure 7) in Figure 8. As in the last-described
arrangement a tube J furnished with slots j is fixed around the orifice, by which
gas enters to the valve, and rods are fixed opposite the slots, but in this arrange-
ment the valve L is of a cap form, and works between the slots j and the rods k. :.
The gases will cause the valve to rise, as shewn in Figure 9, and they will pass
through the slots j and impinge against the rods k, as described with regard to the
arrangement, Figures 5 and 6.
When the charge of the retort. is spent, and the door opened for its removal, the
valve falls, this action thereof removing any matter which may have collected in
the slots or on the rods k, and at the same time prevents the return of the gas.
In place of using slots, as herein-before described with reference to Figures 5 to

page_text: 8, small perforations may be substituted therefor, in which case the valve as it
descends also cleans the sooty matter off from the rods and from off the
perforations.
In cases where the crude gases contain a very large quantity of sooty matter and
a small quantity of tars it may happen that these are not wholly removed by
passing through a single valve. In such cases duplicate valves may be employed,
the gases passing from one valve to the other before their exit to the condensing
and other parts of the apparatus; or a series of valves may be placed on the outlet
for crude gases from the hydraulic main.
The valve arrangement may be placed on the dip pipe below the level of the
liquid in the hydraulic main, as illustrated in Figure 11, where the valve is marked
V. It bears upon a seating-at the end of the dip pipe and opens downwards. It
has a long spindle v, and at the upper end of this spindle is a spring vl, by which
the pressure which the gas has to overcome in passing the said valve into the
hydraulic main is regulated by means of a screw nut v².
I have illustrated and described the best forms of valves with which I am
acquainted for carrying out the objects of iny Invention, but it will be understood
that many other forms of valves may be employed. For instance, instead of
making the valve, Figures 1, 2, and 3, with a single edge, it may consist of a
number of truly turned concentric edges fitting into or resting in truly turned
corresponding concentric recesses or seatings, or of perforated plates with conical
pins in the valve chamber, corresponding to the perforations of the plate, so that
the gases would cause the perforated plate (constituting a valve) to rise from off
the pins, the gases then passing through the perforations. On the perforated plate
falling the pins would again enter the perforations, and clear away any obstructive
matter therein; or it may partake of the character of a sluice valve actuated by a
gas holder, but the forms described and illustrated will, I believe, be found the
most useful in practice.
Apparatus of the kind herein-before described may be also used for the treatment
of gases (other than illuminating gases) which hold solid and vaporous matters in
suspension, such, for example, as the gases from blast furnaces, lead sinelting
furnaces, and other furnaces or apparatus wherein metals are treated, coke ovens,
"Siemens" and other gas furnaces, a fan or other device being employed to draw
or drive the gas through the valves.
In the case of gases which do not contain sufficient tarry or other fluid matters
to entangle and wash away the suspended finely divided dust or sooty matters as
they are precipitated, fluids of a suitable character, such as water for ordinary dry
dust, or oils, or liquid tars, either mineral or vegetable, for sooty dust or pitchy
tars, may be showered over the valve cover.
Another purpose to which these valves may with advantage be applied, is the
eliminating of ammonia from gases, and for the purpose of separating from
illuminating gases carbonic acid and sulphuretted compounds, by means of liquid
purifying agents.
In Figure 10 I have illustrated an arrangement of scrubber M, suited for all the
aforesaid purposes, the said Figure being an elevation with the two upper chambers
in section, shewing in the top chamber the valve arrangement in section, and in the
next chamber the valve arrangement in elevation. The bottom chamber is also
sliewn partly in section. The scrubber is divided into a series of chambers m, in
the bottoms of which are orifices n (see the top chainber), surrounded by valve
seatings n', upon which rest valves P, the spindles p, of which work in guides p¹, 5
and are furnished with stops p². The outer surface of the valve seating is inclined
inwards and downwards as shewn. Surrounding the valve opening is a concentric
deflector Q, formed of a curved upper part q, and a depending inner rim q', which
is opposite the valve opening, and at but a short distance therefrom extending up-
wards to a slight distance above the said opening, and downwards to some distance 5
below the said opening, the said rim q¹ being inclined to correspond with the
inclination of the exterior of the valve seating n¹. The liquid alsorbent employed

page_text: is fed into the scrubber through the pipe r, to a level in each chamber, which is
slightly above the valves when open to their greatest extent. The liquid flows
downward from chamber to chamber by the pipes R, whose mouths are at such an
elevation, as will maintain the level of the liquid in the chambers at the height
aforesaid.
The gas to be purified is admitted by the inlet at S; and passes upward through
the valves in the several chambers m, it raising the said valves, and in passing
therethrough causing a current of the absorbent liquid to flow around 'the deflectors
Q, and through the spaces between the said deffectors and the exteriors of the valve
seatings n (as indicated by the arrows in the top chamber), by which the gases
come in the form of a thin sheet or stream into intimate contact with the absorbent
liquid, and are thoroughly purified, finally leaving the scrubber by the outlet T.
The liquid as aforesaid enters by the pipe 'r, and leaves by the pipe 8, in 'the'
lowest-chamber.
The pipe U, with branches u to each chamber, and provided with cocks v,..
between each chamber, is for the purpose of emptying any chamber or chambers of
its or their liquid contents, or for the purpose of discharging the liquid contents' of
any one chamber into the chamber below it.
The pipes R are led to such a distance over the valves, as that the liquid
absorbent is showered down over the said valves, and consequently the said liquid
as it reaches the edges of the cover, is effectually commingled with the sheet or
stream of gases escaping through the valves, and thus à very perfect absorption' is
effected.
In practice with the valves herein-before described, I have found that the best
results are obtained by making the width of the fixed openings of the valves shewn"
in Figures 4 to 8, and the depth of the varying 'opening made by the rising of the
valve shewn in Figures 1 to 3, as thin as possible,
In cases where the gases and substances passing through the apparatus con-
stituting this Invention are such as to corrode or otherwise act upon metals, the
said apparatus may be made of glass, fire-clay, or other substance not so acted upon
by the said gases and substances; and as the valves when made" of such substance
are heavier, than when made of metal, the valve is balanced by a counterweight:
Another part of this Invention relates to improvements in the manufacture of'
illuminating gas, the objects being to produce a gas of high illuminating power,
freedom from sulphur compounds, and non-liability to deposit crystalline naphtha
in the main and branch pipes during distribution.
This part of the Invention consists in carbonizing the gas-producing materials in
separate retorts, at temperatures which will produce the greatest volume of gas in
the one case, and of illuminating constituents in the other.
Should the gas-producing materials be of different qualities, one being more
bituminous than the other, the poorer material is distilled at a very high tem-
perature, so as to liberate as far as possible the hydrogen of its constitution in the
gaseous form, either combined as carburetted hydrogen, or free hydrogen, and
preferably as much in the state of free hydrogen as possible; the other or inore
bituminous substance is carbonized at a comparatively low temperature, little over
dull redness, say.a temperature of from 900° to 1300° Fahrenheit.
In the event of the gas-producing materials being of one quality, a proportion of
each is distilled separately at different temperatures in the manner just described.
Or the temperature of the retort producing rich gas may be very high, but the
temperature of the distilling bituminous matter may be kept low by a large current
of cold poor gas.
•
The poor gases (or those produced at high temperatures) are freed from their
suspended tarry and sooty matter, by preference, by means of the apparatus pre-
viously described, and are then passed through or mingled with the rich gases (or
those produced at low temperatures) whilst warm, preference being given to passing
the prepared poor gases through the material undergoing carbonization for the
production of the rich gas, in the manner explained in the Specification of the

page_text: invention for when Letters Patent numbered 1246, were granted to me as of th
29th March 1877.
As the poor gases will form the great bulk of the illuminating gas, they ar
admitted by a larger inlet than that shewn in the Drawings of the Patent re
ferred to.
prefer to allow the said poor gases to pass upwards through the gas-producing
material in a vertical retort.
The mingled gases are next subjected to condensation, the liquid matters being
(by preference) precipitated by means of the apparatus herein-before described, and
are thereafter subjected to the usual purifying process, and passed to the gas holder
When the tarry oils resulting from the distillation of the gas-producing material
would be of small commercial value, they may with advantage be run (either from
the hydraulic main or from the chamber containing the valve) back into the retort
and subjected to the further destructive distillation, this being effected by means of
an inverted syphon or other sealed pipe connecting the hydraulic main, or the
chamber containing the valve to the stand pipe, and provided with a cock for
regulating the flow as is well understood, care being taken that no water is allowed
to collect, and therefore pass from the hydraulic main into the retorts.
Should the temperature at what the poor gas is produced be so high as to
decompose nearly all the liquid tarry hydrocarbon, and leave a large quantity of
sooty matter, the liquid oily tars produced from the low heated retorts are employed
to wash the poor gases either by running the tars into the hydraulic, or over the
valve apparatus, or down the stand pipes into the retorts.
'
By conducting the manufacture of gas in this manner, a gas of high illuminating
power is produced. The sulphur hydrocarbon compounds, which are necessarily
present in the poor gas made at high temperatures are, in the manner well known,
by the reheating of the gas in the low heated retorts converted in great part into
sulphuretted hydrogen and deposited carbon, the sulphuretted hydrogen being easily
removed by the ordinary process of purification, and a gas free from sulphur is
produced.
When the poor gas has been produced from common coal it will contain con-
siderable quantities of naphthaline; the carburetting of the poor gases by the hydro-
carbons produced at low temperatures prevents the precipitation of this material.
Having now described and particularly ascertained the nature of my said
Invention, and the system, mode, or manner in or under which the same is or may
be used, or practically carried into effect, I would observe in conclusion that what
I consider to be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,-
First. The valvular apparatus essentially as herein-before described and shewn in
Figures 1 to 9 of the accompanying Drawings; that is say, a valvular apparatus
situated between the hydraulic main and the retorts, whereby the separation of the
soot and tarry matter from the gas is effected, and the pulsatory action in the
retorts is prevented as set forth.
Second. The arrangements in the valvular apparatus herein-before described,
whereby the valves are rendered self-cleaning.
Third. The cleansing of the valves, the removal of sooty and other solid or liquid
matters, and the separating or recovering of ammonia or other substances from
gases, by discharging over the valves tars, oils, or other liquids, essentially as herein-
before described.
Fourth. The arrangement of apparatus shewn in Figure 10 of the accompanying
Drawings, or any mere modification thereof, for the purpose of separating solids or
liquids from gases generally, and also for the separation of the gaseous impurities
from illuminating gas, such as ammonia, sulphuretted hydrogen, and carbonic acid.
Fifth.. The improvements in the manufacture of illuminating gas herein-before
last described, consisting in carbonizing the gas-producing materials in separate
retorts, at temperatures which will produce the greatest volume of poor gas in the

page_text: one case, and the greatest amount of illuminating constituents in the other case, the
poorer gas being first purified from tarry and sooty matters, and then passed into
the retort in which the bituminous matter is undergoing distillation at a low tem-
perature, essentially as herein-before described.
In witness whereof, I, the said William Young, have hereunto set my hand
and seal, this Sixth day of August, in the year of our Lord One thousand
eight hundred and seventy-eight.
•
WILLIAM YOUNG. (L.S.)