Improvements relating to the Carburetting or Enrichment of Coal and other Gas, and to Apparatus therefor.
Year: 1890

page_text: This Print is in accordance with the Original Specification as it stands after
Amendment (under Section 18 of the Patents, &c., Act, 1883), as allowed by
the decision of the Chief Examiner of the 24th day of August 1896.
PROVISIONAL SPECIFICATION..
Improvements relating to the Carburetting or Enrichment of Coal
and other Gas, and to Apparatus therefor.
We, HIRAM STEVENS MAXIM, of Crayford, in the County of Kent, and Victoria
Mansions, in the City of Westminster, Mechanical Engineer, and GEORGE STANLEY
SEDGWICK, of Suffolk House, Laurence Pountney Hill, in the City of London,
Managing Director, do hereby declare the nature of this invention to be as follows:-.
Our invention relates to the carburetting or enrichment of coal and other gas
and to apparatus therefor, and is chiefly designed to provide for increasing the
candle-power of gas as it flows through the mains from gas-works, for the purpose
of raising it to, or above the usual standard.
In cases where it is desired to enrich very large quantities of gas flowing through
the mains, it is not practicable to pass the whole of the gas through the carburetting
apparatus. According to one part of our said invention, therefore, we draw a
suitable quantity of gas from the main at any convenient part thereof, pass the said
gas through the carburettor and thus enrich it to a high degree, and then conduct
it back into the main, wherein it becomes intimately mixed with the ordinary gas
and raises the same to the required standard or candle-power. Or we introduce
directly into the main at any convenient part thereof, or into a gasometer or the
like, a quantity of hydrocarbon vapor sufficient to raise to the required standard
or candle-power the gas flowing through the said main or contained in the said
gasometer.
Our improved apparatus comprises an evaporator or retort for volatilizing gasoline,
naphtha or other suitable hydrocarbon by means of steam or other hot water. The
said apparatus is preferably placed very near the gas-main, to which it is connected
in two places by means of pipes of suitable diameter. One of these pipes conducts
the gas from the main to the carburettor. The other of the said pipes conducts the
highly enriched gas from the carburettor into the main. The circulation of the gas
from the main through the carburettor and back to the main is effected by the
dynamic force of the volatilized hydrocarbon by means of an injector. This injector
is so arranged in combination with the evaporator or retort and with the said con-
ducting pipes, that the hydrocarbon vapor. passes through the injector in such a
manner as to draw the gas out of the main and force it, when mixed with the said

page_text: vapor,
back into the said main, the bydrocarbon vapor being discharged with con-
siderable force from the injector-nozzle in the form of an annular or other suitable
jet, into a mixing-chamber or tube connected with the said conducting pipes for
the gas.
The valve of the said injector is combined with an index for showing to what
extent the injector is open, and consequently to what degree the gas is being
carburetted.
In some instances, the evaporator or retort is heated by steam, which enters the
said evaporator or retort through a pipe from the boiler, and leaves it through another
pipe provided with a suitable steam trap, and we combine, with the evaporator or
retort or with either of the said steam-pipes, a controlling apparatus comprising a
diaphragm which operates a valve for the supply of liquid hydrocarbon to the
vaporizing-chamber. The said liquid is introduced into the vaporizing chamber
through a suitable pipe connected with the said controlling apparatus, the valve of
which is held against its seat by a powerful spring or its equivalent. When steam is
turned on, the pressure of the steam operates on the diaphragm, compresses or
extends the spring as the case may be, and opens the valve for the liquid. It will be
seen therefore, that the liquid-valve will not be open until after the evaporator or
retort has become heated. If however, from any cause, the supply of steam should
fail, instead of the liquid continuing to flow into the machine and thus filling it and
overflowing, the valve for admitting such liquid will be closed by the said spring.
The said controlling device is preferably so constructed that the steam will act upon
the diaphragm through the medium of a body of water, which is allowed to accumulate
by the condensation of the steam above the said diaphragm.
It is obvious however, that the said device may be modified in various ways if
desired.
We find it advantageous to make our evaporator or retort with a cylindrical
shell, which is closed at its upper and lower ends by suitable plates, and is divided
into three compartments. by means of tube-plates. In these tube-plates are fixed
vertical tubes which extend through the middle compartment and connect the upper
and lower compartments. The liquid gasoline or other hydrocarbon is admitted
beneath the lower tube-plate. The steam or hot water is caused to pass through
the middle compartment and come in contact with the. exterior surface of the said
tubes.
The hydrocarbon, as it is vaporized, rises in the said tubes and the vapor is
conducted away from the top of the evaporator or retort through a suitable pipe
to the injector, or to the mixing-chamber, or directly into the main as may be
desired. Or the steam is caused to pass. through the tubes and the hydrocarbon
is brought into contact with the exterior surface of the said tubes. Or we make
the evaporator or retort with a jacket or casing, surrounding, the vaporizing-chamber,
or with both a jacket or casing surrounding it and tubes extending through it for
the circulation of the heating medium. Or we provide it with a suitable heating
coil.
When we employ an injector, for effecting the circulation of the gas through the
carburettor, we find it advantageous to employ a pump for forcing the liquid hydro-
carbon into the evaporator or retort, and to combine with the said pump, a suitable
air-vessel or chamber whereby the requisite head or pressure can be maintained, we
-can however, obtain the required head or pressure by means of any elevated tank, or
in any other convenient manner.
When the hydrocarbon vapour is to be introduced, directly into the gas-main or
into a gasometer or the like, we provide the pipe for conducting the said vapor. from
the evaporator or retort with a cock or valve, whereby the admission of vapor to the
main or gasometer may be regulated or controlled and which is provided with a
suitable index for indicating the extent of opening of the said cock or valve.
In some instances, we combine with the evaporator or retort, a boiler or heater for
generating the steam for vaporizing the liquid hydrocarbon and we provide the said
boiler with one or more suitable burners for heating the said boiler by means of coal-

page_text: gas or other fuel, the supply of which to the said burner or burners is automatically
regulated or controlled by means of a device such as that hereinbefore described,
according to the pressure of the steam in the said boiler.
The said boiler or heater is preferably constructed as follows viz. :-It is provided
with a flue or flues arranged in such a manner that the heated products of combustion
must first ascend and then descend and will escape from the flu or flues at, or near
the level of the burner or burners, so that the columns of air in the said flue or flues
will counterbalance each other and there will be no flow of air through the said flue
or flues when the supply of gas or other fuel is shut off. By this means we provide
for maintaining the water in the heater at a considerable temperature for a long time
after the flame from the burner or burners has been extinguished. We find it
advantageous to make the boiler or heater with vertical tubes or flues connected at
their upper end by a cylindrical chamber which may or may not have a tube or tubes
extending through it for the purpose of increasing the heating surface.
To adapt the aforesaid controlling device for regulating the supply of fuel to the
boiler or heater, we arrange in combination with a valve in the supply-pipe for the
fuel, a flexible diaphragm or its equivalent, one side of which is acted upon by a
suitable spring and the other side by the pressure in the said boiler or heater. To
prevent the overheating of the said diaphragm and thus increase the duration thereof,
we sometimes arrange the said diaphragm at the lower end of a tube or tubular
chamber which extends downward from the boiler or heater and in which there will
be but a slow circulation of the liquid.
When gas is used as fuel for the boiler or heater it is advantageous to provide a
small tube for the passage of gas to maintain an igniting flame, which will continue
to burn when the supply of gas to the main burner is shut off.
The boiler or heater is connected in any convenient manner with the circulating
chamber or space of the evaporator or retort. The said boiler or heater may be
placed at any desired distance from the said evaporator or retort.
The boiler or
heater and the evaporator or retort are preferably covered or lagged with. suitable
non-conducting material.
In some instances we so connect the boiler or heater with the evaporator or retort
that one portion of the heating surface of the said evaporator or retort will be in
contact with hot water and another portion thereof with steam so that the whole of
its heating surface will be in contact with steam. In other instances, we provide for
heating the said vessel or retort entirely by means of hot water.
The boiler or heater is provided with an aperture for enabling it to be filled or
partly filled with water, which aperture is closed by a suitable plug or in any other
convenient manner. It may, if desired, be provided with a safety valve. We
sometimes provide means for preventing the filling of the boiler or heater above a
predetermined level.
+
We also by preference provide means for permitting the escape of air on starting
the apparatus, and for subsequently tightly closing the escape aperture so that the
said apparatus can be worked at a very low pressure.
We can, if desired, employ other means for drawing gas from the main, carburetting
the said gas and returning it to the main, for the purpose above specified. For
instance we might cause the circulation of a portion of the gas from the main through
a carburetting apparatus of the kind or class described in the Specifications of the
following former Letters Patent viz. :-No. 703 dated 14th January 1889, and
No. 2508 dated 12th February 1889, or through other suitable carburetting
apparatus.
Moreover, the steam boiler or heater above mentioned provided with the regulating
or controlling device can be advantageously used with carburetting apparatus such as
that described in the said former Specification No. 2508, or with similar carburetting
apparatus.
Although we have herein before described our improvements more particularly as
applied to the carburetting or enriching of gas flowing through mains or contained in
gasometers or the like it is obvious that the said improvements, or some of them, are

page_text: also applicable in cases where the whole of the gas to be carburetted or enriched is
passed through the carburettor.
Dated this 17th day of February 1890.
HASELTINE, LAKE & Co.,
4, Southampton Buildings, London, Agents for the Applicants.
Improvements relating to the Carburetting or Enrichment of Coal
and other Gas, and to Apparatus therefor.
We, HIRAM STEVENS MAXIM, of Crayford Works, Crayford, in the County of
Kent, and Victoria Mansions, in the City of Westminster, Mechanical Engineer, and
GEORGE STANLEY SEDGWICK, of Suffolk House,. Laurence Pountney Hill in the
City of London, Managing Director do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:—
Our invention relates to methods of and apparatus for carburetting or enriching
coal and other gas by mixing hydrocarbon vapours therewith, and is chiefly designed
to provide for increasing the candle-power of gas as it flows through the mains from
gas-works, for the purpose of raising the quality of such gas to or above the usual
standard.
In cases where it is desired to enrich very large quantities of gas flowing through
the mains, it is not practicable to pass the whole of such gas through the carburetting
apparatus. According to our present invention, therefore, we introduce the hydro-
carbon vapour from the said apparatus into the gas-main as hereinafter described.
Our said invention comprises an improved method of carburetting or enriching
the gas flowing through a gas-main by drawing a suitable quantity of the same from
the main at any convenient part thereof, carburetting or enriching it to a high degree,
and then conducting it back into the main, wherein it becomes intimately mixed with
the remainder of the gas; the whole of the gas is thus raised to the required standard
or candle-power.
Our said invention, moreover, comprises other improvements hereinafter set
forth.
In the accompanying drawings, we have shown how our said invention may be
conveniently and advantageously carried into practice.
Figure 1 is a side elevation showing one arrangement of our apparatus for drawing
a portion of the gas from the main, curburetting or enriching such gas and returning
it to the main.
Figure 2 is a vertical central section, drawn to an enlarged scale, showing one
form of our evaporator or retort for volatilizing the liquid hydrocarbon, connected
with a boiler or heater of improved construction.
Figure 3 is a vertical central section, drawn to a still further enlarged scale, of an
injector which is operated by the hydrocarbon vapour, for the purpose of drawing the
gas from and returning it to the main.
Figure 4 is a side elevation showing another arrangement of our apparatus, whereby
we provide for the introduction of the hydrocarbon vapour in the required quantity
directly into the gas-main, and
Figure 5 is a side elevation, partly in vertical central section, showing our improved
boiler or heater and evaporator or retort applied to apparatus such as that described
in the Specification of former Letters Patent granted to the said Hiram Stevens
Maxim and dated 12th February A:D. 1889, No. 2508.
Like letters indicate corresponding parts throughout the drawings.

page_text: A is the evaporator or retort for volatilizing the liquid hydrocarbon. B is a steam
generator or boiler for heating the said evaporator or retort. C is a storage tank for
the liquid hydrocarbon, which tank is connected by a pipe D with a pump E for
raising the liquid hydrocarbon from the storage tank and forcing it through a
pipe D into a tank F situated at a higher level, so as to obtain the required head or
pressure for forcing the hydrocarbon vapour from the evaporator or retort A into the
gas-main G.
In the apparatus shown in Figures 1 to 3, an injector H is connected with the
gas-main G by pipes J, K for the purpose hereinafter specified.
The evaporator or retort A is constructed with a cylindrical shell «, Figure 2, which
is closed at its upper and lower ends by suitable plates a' and is divided into three
compartments by means of tube-plates a³, a³. In these tube-plates are fixed vertical
tubes a' which extend through the middle compartment and connect the upper and
lower compartments of the evaporator or retort. The liquid hydrocarbon from the
tank F is admitted to the compartment beneath the lower tube-plate a³ through a
pipe which is provided with a stop-cock b¹ and the end of which within the retort
is provided with a T-shaped piece for the purpose of distributing the hydrocarbon
throughout the lower compartment of the retort, and thus preventing its introduction
directly into the tubes at at the centre of the retort. The steam from the boiler B is
admitted to the middle compartment of the retort through a pipe c and comes in
contact with the exterior surface of the said tubes a, and the water of condensation
returns to the boiler B through a pipe d. A pipe e is, moreover, provided for
conducting the hydrocarbon vapour from the top of the retort A to the injector H and
this pipe is provided with a suitable stop-cock or stop-valve e for controlling the flow
of hydrocarbon vapour to the said injector.
Although we have shown the boiler and retort placed at about the same level, we
prefer to so arrange them relatively to each other that the normal water-level (which
is the same in both the boiler and the retort) will be a short distance above the aperture
in the retort which communicates with the outlet-pipe d, as shown in Figure 5.
We combine with the evaporator or retort, a regulating or controlling apparatus
comprising a suitable casing which is provided with a flexible diaphragm f¹
(Figure 2) and which is in communication with the steam inlet-pipe c. A valve g is
arranged in the pipe b for the supply of liquid hydrocarbon to the evaporator or retort,
and this valve is held against its seat by a spring g'. The said diaphragm f is
connected with the valve g by means of a rod h. When the steam is admitted to the
evaporator or retort for the purpose of volatilizing the liquid hydrocarbon, the pressure
of the steam acting upon the diaphragm f compresses the spring g' and opens the
valve I, thus permitting the flow of liquid hydrocarbon into the retort. It will be
seen, therefore, that the valve g will be opened when, but not until the retort has
been in some measure heated by the steam. Moreover, if from any cause the supply
of steam should fail, instead of the liquid continuing to flow into the retort and thus
filling it and overflowing, the valve g will be closed by the reaction of the spring 1
and the supply of liquid hydrocarbon thus arrested. It is desirable to form a hole
through the said valve or through its seat, or to provide some other suitable bye-pass
to permit the return of the hydrocarbon liquid from the retort if necessary.
We sometimes substitute for the valve shown in Figure 2, a taper or needle valve.
whereby the supply of liquid hydrocarbon to the retort will be regulated according
to the pressure of the steam admitted to the retort for the purpose of heating the
same.
The said regulating or controlling device is preferably constructed with a tube
or tubular chamber above the diaphragm 1 as shown, so that the steam will act
upon the diaphragm through the medium of a body of water, which is allowed to
accumulate by the condensation of the steam above the said diaphragm. We thus
obviate any liability to overheating of the said diaphragm by the steam.
It is obvious that the said device may be modified in various ways if desired. For
instance, instead of the spring g', we can provide a lever acted upon by a suitable

page_text: :
spring or weight for keeping the valve against its seat. Or the spring g' can be
so arranged that it must be extended instead of compressed to open the valve g.
The lower compartment of the retort A is provided with a cock j for drawing
off any liquid hydrocarbon which would otherwise remain unvolatilized in the said
retort.
The circulation of the gas from the main through the mixing-chamber and back to
the main is effected by induction by the volatilized hydrocarbon through the medium
(of the injector H, more clearly shown in Figure 3. This injector has a nozzle H'
which can be put in communication through the stop cock or valve el and pipe e with
the evaporator or retort. In the said nozzle is arranged an adjustable taper or conical
valve k, the screw spindle k of which is provided with a suitable hand-wheel An
inner casing or lining is secured in the outer casing of the injector, to form a
contracted mixing-chamber therein. The outer casing is provided with a flange H³
for connecting it to the pipe J, and with a flange H³ for connecting it to the
pipe K.
+
It will bo seen that the said injector is so arranged in combination with the
evaporator or retort and with the said pipes J, K, that the hydrocarbon vapour
which passes through the injector will draw a quantity of gas out of the main and
force. it, when mixed with the said vapour, back into the said main, the hydro-
carbon vapour being discharged with considerable force from the injector-nozzle H'
in the form of an annular jet, into the contracted mixing-chamber l.
The spindle of the said injector has combined with it a cylindrical or tubular
piece m provided with a graduated scale and operating in conjunction with a fixed index
or pointer n for showing to what extent the injector is open and consequently to what
degree the gas is being carburetted or enriched.
The boiler or heater B shown in Figure 2 is constructed as follows, viz. :-It is
provided with flues', p' so arranged that the heated products of combustion from
the burner o must first ascend through the flue p and then descend through the
flue p' and will escape from the said flue p¹ a short distance above the level of the
burner o; the columns of air in the said flues p, p' will therefore counterbalance, or
nearly counterbalance each other, and there will be no flow of air through the said
flues, or the air will move but slowly through the said flues, when the supply of gas
or other fuel is shut off. By this means the water in the heater will be maintained
at a comparatively high temperature for a considerable length of time after the flame
from the burner or burners has been extinguished, the rapid circulation of cold air
through the flues being prevented. The air for supporting combustion is admitted
through one side of a casing y below the shell of the boiler, and the heated products
of combustion escape through the other side of the said casing, a suitable partition or
diaphragm g¹ being provided for separating the flues at their lower end. We find it
advantageous to connect the tubes or flues p, p¹ at their upper end by a cylindrical
chamber constructed either with or without one or more tubes r¹ extending through
it, for the purpose of increasing the heating surface.
We sometimes adapt the regulating or controlling device hereinbefore described,
for the regulation or control of the supply of fuel to the boiler or heater, that is to
say, we arrange, in combination with the supply pipes for the gaseous or other fuel,
a casing fin which is arranged a valve 9 for regulating or controlling the flow of the
fuel; a flexible diaphragm is arranged in the casing f and is acted upon at one
side by a suitable spring 9 and at the other side by the pressure in the said boiler
or heater. To prevent the overheating of the said diaphragm and thus increase the
durability. thereof, we prefer to arrange the said diaphragm at the lower end
of a tube or tubular chamber which extends downward from the boiler or heater,
and in which there will be but a slow circulation of the liquid.
When gas
used as fuel for the boiler or heater, it is advantageous to provide a
small tube t for the passage of gas to maintain an igniting flame, which will continue
to burn when the supply of gas to the main burner is shut off.
The boiler or heater is provided with an aperture u for enabling it to be filled

page_text: or partly filled with water, which aperture is closed by a suitable plug ¹; or it
may be closed in any other convenient manner. It may, if desired; be provided with
a safety-valve. We sometimes. provide suitable means for preventing the filling of
the boiler or heater above a predetermined level. For instance, we fit into the
aperture u, a tube extending downward to the desired, water-level.
We also, by preference, provide suitable means for permitting the escape of air
on starting the apparatus and for subsequently tightly closing the escape aperture-
so that the said apparatus can be worked at avery low pressure.
We find it advantageous, in some instances, to employ a steam-pump E provided
with a controlling device E' comprising a self-acting diaphragm-valve, whereby, as.
soon as a certain pressure is attained in the tank F, the steam-supply to the said
pump will be shut off, and, when such pressure diminishes, the steam-supply will be
opened and the pump again allowed to operate. We thus ensure the maintenance of
a constant or approximately constant pressure in the tank F and retort A. Or we
combine with a suitable pump, an air-vessel or chamber whereby the requisite.
head or pressure can be maintained. We can, however, obtain the required head or
pressure simply by the elevation of the tank above the retort, or in any other
convenient manner.
The operation of the apparatus shown in Figures 1, 2 and 3 is as follows, viz. :-
The tank C is filled with gasoline or other suitable liquid hydrocarbon, a suitable.
quantity of which is pumped from the tank into the tank F. The stop-cock 6' is
then opened to permit the flow of liquid hydrocarbon from the tank F. On the
admission of steam or hot water to the retort A through the pipe c, the valve ġ is
opened, and the hydrocarbon thus allowed to flow into the retort, in which it is heated
by the steam or hot water as the case may be, and is thereby volatilized. The
pressure thus generated in the retort forces some of the liquid hydrocarbon back into
the tank F. On opening the cock or valve e', and adjusting the valve k of the
injector H as required, the hydrocarbon vapour is forced through the nozzle H' in the
form of an annular jet, which induces a current of gas from the main G through
the pipe J and forces the said gas intermingled with the hydrocarbon vapour through
the pipe K back into the main, wherein the gas thus enriched becomes intimately
mixed with the ordinary coal-gas, thus raising the standard or candle-power thereof.
It will, therefore, be seen that the whole of the gas does not require to pass into or
through the carburettor.
By altering the adjustment of the valve K of the injector, the quantity of vapour
thus introduced into the gas-main can be varied as required.
1
When the hydrocarbon vapour is to be introduced directly into the gas-main
without drawing a portion of the gas therefrom and returning it thereto as above-
described, we provide a pipe which extends from the cock or valve el on the pipe e-
into the gas-main as shown in Figure 4, and the end of which within the gas-main.
is preferably provided with a contracted mouth or nozzle, as at . The admission
of the hydrocarbon vapour to the main is, in this instance, regulated or controlled by
the cock or valve e' which is provided with a suitable index or pointer and graduated
scale for indicating the extent of opening thereof.
It will be seen, that in this arrangement of our apparatus, none of the gas passes..
into or through the carburettor.
The steam boiler or heater constructed with the flues for the ascent and descent of
the heated air or products of combustion and provided with the regulating or
controlling device as above described, can be advantageously used with carburetting
apparatus such as that described in the said former Specification No. 2508, or with.
similar carburetting apparatus, as shown for example in Figure 5. In this figure-
we have shown an evaporator or retort and boiler or heater such as we have herein-
before described combined with a mixing-chamber w and regulating bell or
gasometer w such as are described in the said former Specification, the pipe e being
provided at its upper end with a valve w³ connected with, or .controlled by the
gasometer to¹.

page_text: In the retort shown in Figure 5, the liquid hydrocarbon is admitted to the middle
compartment, that is to say, into the space between the tube-plates a³, a through one
or more holes in the pipe b, and the steam or hot water is caused to circulate through
the tubes a. The gasoline vapour passes through holes in the pipe e and flows into
the mixing-chamber w, its admission being regulated by the valve w* and gasometer w¹.
Suitable means are provided for causing a portion of the gas from the main to pass
through the mixing-chamber w.
We sometimes make the evaporator or retort with a jacket or casing surrounding
the vaporizing-chamber, or both with a jacket or casing surrounding it and with tubes
extending through it for the circulation of the heating medium which may be steam
or hot water. Or we provide it with a suitable heating coil.
The boiler or heater may be connected in any convenient manner with the circulating
chamber or space of the evaporator or retort.
In some instances, we so connect the said boiler or heater with the retort that one
portion of the heating surface of the said retort will be in contact with hot water and
another portion thereof with steam as shown in Figure 2; or so that the whole of
its heating surface will be in contact with steam as shown in Figure 5. Or we provide
for heating the said retort entirely by means of hot water. The said boiler or heater
and the evaporator or retort are preferably covered or lagged with suitable non-
conducting material. The retort and the boiler or heater may be placed at any
convenient distance from the supply tank or tanks, and the boiler or heater may be at
any desired distance from the said retort.
We can, if desired, employ with advantage other suitable means for drawing gas
from the main, carburetting the said gas and returning it to the main, for the purpose
above specified. For instance we can provide for the circulation of a portion of the
gas from the main through a carburetting apparatus of the kind or class described
in the Specification of former Letters Patent granted to the said Hiram Stevens
Maxim and dated 14th January 1889, No. 703, or through other suitable carburetting
apparatus.
We are aware that hydrocarbon has, in some instances, been introduced in a liquid
state into a gas-main for the purpose of enriching the gas therein. This method of
carburetting the gas is, however, objectionable. We in all cases volatilize the
hydrocarbon prior to its introduction into the gas main in the manner described
by us.
We are also aware that it has been heretofore proposed to pass the gas-supply or
part thereof through a carburettor in order to enrich it, providing at the same time a
bye-pass by which a portion of unenriched gas may be allowed to flow on and join
the enriched gas, the bye-pass being constricted so that gas from the supply-pipe is
forced to pass through the carburettor by reason of such constriction. We do not
desire to claim such an arrangement, but we limit our claim to an arrangement in
which a portion of the gas is drawn from the main through a bye-pass by an injector
or other suitable means, so that the uninterrupted flow of the gas through the main
may be maintained.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed we wish it understood, that
subject to the disclaiming note we claim :-
First. The method of carburetting or enriching the gas flowing through a gas-
main, by drawing a suitable proportion of such gas from the main, carburetting or
enriching the same and returning it to the main, substantially in the manner herein-
before described.
Second. The combination, with an evaporator or retort for volatilizing liquid bydro-
carbon, of an injector which is operated by the hydrocarbon vapour from the said
evaporator or retort, and which draws gas from a gas-main, enriches such gas and
returns it to the main, substantially as herein before described.
Third. The combination, with a gas-main, of an evaporator or retort for volatilizing

page_text: liquid hydrocarbon, a steam or hot water heater connected with the said evaporator or
retort, an injector connected with the said evaporator or retort and operated by the
hydrocarbon vapour therefrom, and suitable pipes connecting the said injector with
the gas-main, substantially as, and for the purposes, above specified.
Dated this 17th day of November 1890.
D. YOUNG & Co.,
11 & 12 Southampton Buildings, London, W.C., Agents for the Applicants.