IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE OF GAS FROM LIQUID HYDROCARBONS AND STEAM
Year: 1883

page_text: LETTERS PATENT, to Alexander. Melville Clark of the firm of A. M and
W. Clark of 53 Chancery Lane in the County of Middlesex Fellow of the
Institute of Patent Agents for an Invention of IMPROVEMENTS IN APPARATUS
FOR THE MANUFACTURE OF GAS FROM LIQUID HYDROCARBONS AND STEAM
communicated to him from abroad by Magnus Gross of the city, county and
☐ state of New York, United States of America
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 22nd May 1883.
ALEXANDER MELVILLE CLARK of the firm of A M and W. Clark of 53 Chancery
Lane in the County of Middlesex Fellow of the Institute of Patent Agents
"IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE OF GAS FROM LIQUID
HYDROCARBONS AND STEAM [communicated to him from abroad by Magnus Gross
of the city, county and state of New York, United States of America]
The object of this Invention is to furnish for the purpose of making illuminating
or fuel gas from crude oil, naptha, or other liquid hydro-carbons, and superheated.
steam, and improved retort by the aid of which, disassociation and readjustment of
the constituents of any liquid hydrocarbons and steam, can be accomplished simul-
taneously, and in the nascent state, and a gas for lighting and heating will be
produced of from eighteen to thirty candle power, and so thoroughly fixed that it
will emit neither smell nor smoke while being burned, and which will require no
other purification but condensation, and in which the percentage of carbonic oxide
is completely under the control of the operator, and the formation of carbonic acid
or any explosive gas mixture is rendered impossible for the reason that the access
of atmospheric air is wholly prevented.
A further object of this Invention is to provide an improved steam superheater
for the purpose. First, of securing a thorough and uniform superheating of steam
for gas making or other purposes. Second, of preventing steam or the products of
its decomposition from coming in contact with impurities. Third, of avoiding the
use of extra fuel. Fourth of protecting the iron pipes in such a manner that the
superheater can be worked without interruption for a year or longer, instead of
only for a few months, before being rendered brittle and becoming used up. Fifth,
of avoiding the reconstruction of a furnace and the consequent stopping of
operations while placing a new superheater. Sixth of saving so far as practicable,
r

page_text: all the heat imparted to the steam and thus preventing the breaking down of the
heat of the retorts or generators through which the steam is led to be decomposed
for the manufacture of water gas, or other purposes; and seventh, of thoroughly
controlling the velocity and volume of the steam passing through the superheater.
Whenever steam is used for the purpose of decomposition and the combination i
of its elements hydrogen, and oxygen, with other gaseous bodies, or in the manu-
facture of water gas, the great hinderance to any such operation lies in the fact,
that the steam in passing through retorts, generators, or other apparatus, con-
structed for such purposes quickly lowers the heat required for the safe conduction
of such processess, rendering them intermittent and unreliable instead of constant
and uniform as they ought to be.
For the purpose of rendering the process of making gas from naptha or other
liquid hydro carbons more perfect the present apparatus which meets the require-
ments and avoids the difficulties herein before mentioned as attending the use of
superheated steam has been devised.
In this apparatus the retort is made open at both ends and is divided practically
into three chambers, in the manner hereinafter described. The central part of the
retort for about three fifths of its length is exposed to the full heat of the furnace
and is kept in a state of bigh 'incandescence, and is filled with any convenient
highly porous material. To the centre of the upper part of the retort is secured a
piece of chamotte, which projects downwards several inches, and serves as a flange
or bridge to deflect in a downward, direction, all gas or vapors that strike against
it, and which may be replaced by a diaphragm having a central opening if
desired.
i:
Into the retort near its forward end and close to the porous material, is,
hermetically fitted, a correspondingly shaped heavy cast iron plate, in the centre of
which is formed a circular aperture about four inches in diameter, through which
as an outlet, all gases must pass before they can enter the stand pipe attached to
the mouth piece in the ordinary manner. To this plate may be attached a basket
made of strong iron bars wherein to imbed the porous material in case it should be
desired to use a combustible substance, as coke for instance, needing renewal every
two or three months.
If the porous material used be incombustible' the retort need never be opened,
or the operation of gas making interrupted, except for the purpose of repairing
cracks.
The basket is centred in the retort by diaphragms of chamotte or other suitable
material which have openings formed through them to receive and fit upon the
said basket. The forward diaphragm serves as a stop for the plate to rest against
and also as a cover to the joint between the said plate and the retort. The rear
diaphragm serves also as a flange to deflect the steam and vapor into the incan-
descent material whether a basket be used or not.
The lower side of the forward end of the basket is rounded or bevelled for
convenience in inserting it in the retort and a downwardly projecting flange is
attached to the upper part of the retort in such a position as to serve as a stop for
the basket and as a deflector to cause the gases and vapor to enter and pass through
the incandescent porous material.
If fuel gas is to be made in any one of the retorts to serve as a feeder for the
bench or boiler furnace, or other purpose, the connection with the stand pipe is
interrupted by closing the valve in said pipe and the gas is led to the furnace or
other place through pipes attached to the bottom and side of the mouth piece. If
the fuel gas is to go to a holder it is allowed to pass out through a pipe connected
with, and projecting horizontally from the stand pipe the said pipes being provided
with valves for controlling the exit of the gas.
To the open rear end of the retort is attached a cast iron mouth piece of less
weight and outward projection-than the front mouth piece, through an aperture in
the centre of the upper part of which passes the oil pipe an through an aperture
in the lower part of which passes a pipe for introducing superheated steam. These

page_text: pipes are provided with valves so that the amount of oil and steam delivered to
the retort can be regulated as desired.
The inner end of the oil pipe is curved downward so that the oil or naptha will
drop upon hot perforated plates made with upwardly projecting rims, and
supported by rods or other suitable means, in the middle rear part of the
retort.
The steam pipe enters beneath the perforated plates and its inner end is bent to
one side so that the entering steam will strike one side of the mouth piece or of
the rear end of the retort and will be thrown back and made to commingle with
the vapor of the oil or naptha formed by the contact of the said oil or naptha with
the hot perforated plates and with the still hotter steam.
The rear mouth is thickly coated with a non-conducting cement to prevent loss
of heat from radiation, and the cooling effect of the outside air.
Thoroughly superheated steam and the vapor of oil or naptha intimately mixed
in proper proportions are drawn by the action of a steam jet, or exhauster placed
between the hydraulic and condenser through the length of the retort which
becomes gradually hotter toward its centre. The retort is constantly filled with
an atmosphere of incandescent carbon, which causes the ready decomposition of
the steam into its elements, and the combination of the said elements in the
nascent state, with the highly heated vapors of the liquid hydro-carbon into a
compound of fixed combustible gases, consisting mainly of heavy hydrocarbons of
the ethylene series the illuminators proper, of light carburetted hydrogen of the
methylene series of pure hydrogen, carbonic oxide, and a certain percentage of
the vapors of tar; no nitrogen, carbonic acid; ammoniacal or sulphurous
compounds, or any other impurities being present or formed to pass out of the
retort.
The porous material in the heated part of the retort, the bridge-like projection
in the centre, and the contracted outlet in the middle of the front plate, prevent
any of the vapors or gases from leaving the retort before having come in contact
with and passing through the incandescent porous material and thus becoming
thoroughly fixed, except such particles of tar as remain suspended in the hot gas
till the latter reaches the condenser and the tar drops out of the cooled gas, which
without any further treatment of any kind or manner is now fit for use.
To ensure permanency and uniformity in the operation of gas making by the
use of this improved retort, the said retort should be placed in a bench, which'
should have not less than six, and may contain as many as nine generating or
distilling retorts and in which is inserted an additional retort open at both ends
for the purpose of housing the superheater. The forward part of this retort rests
upon a double wall and never becomes very hot. Its rear part rests upon the rear
wall of the bench, and upon a partition wall, placed at a little distance from the
rear wall and forming a chamber through which the products of combustion pass
from the main or furnace chamber to the chimney and with which the interior of
the retort communicates by means of an opening so that all rarefied and highly
heated air, spent fire-gases, or vapors in the superheating retort pass into the hot
air chamber and thence to the chimney.
By this construction an even and uniform tension is maintained in the
superheater, and at the same time, the possibility of a vacuum is avoided
On the bottom of this retort are placed four or five rows of pieces of chamotte
or fire brick at equal distances apart and which are covered and the spaces"
between them are filled to the depth of several inches, with pulverized fire clay.
The retort is now ready to receive the superheater proper which is constructed as
follows:-
From twelve to fifteen lengths of wrought iron-pipe of double or triple the
ordinary thickness, forming, when connected a length of not less than one
hundred feet, are connected at their ends by return bends and the connected pipe
is provided at one end with an inlet pipe and at the other end with an outlet pipe
which inlet and outlet pipes are only one third the diameter of the superheating

page_text: pipe. The lengths of pipe before being connected by the bends are carefully
rubbed inside and outside with finely ground dry plumbago till no more will
adhere to the iron. Pads of hair felt, such as is used in covering boilers and steam
pipes, are cut into strips two or three inches wide and half an inch thick and are
coated upon the inner surface with a thick paste made of plumbago and warm
water. The strips thus prepared are wound around the pipes, covering them
nearly to the screw threads that screw into the bends. To the outer surface of the
wound strips is applied strong but not too stiff asbestos paper cut into strips and
thickly coated on the inner surface with the plumbago paste. The strips of felt
and asbestos paper are then secured in place by iron wire wound around them and
the pipes. The pipes thus prepared and after being connected by the return bends
receive a final coating of a wash made of powdered plumbago, fire clay, and warm
water.
The parts of the superheater that are to be subjected to incandescence are
wrapped in sheets of asbestos paper, coated inside and outside with the same
plumbago and clay paste, and secured in place by strong wire
The superheater thus prepared is placed in position in the retort, and is
practically indestructible, since no fire-gases, hot air, or vapors, that may be at any
time in the superheating retort, will attack the pipes, the carbonization of the hair
felt securing a free space into which the said pipes can expand as they are enlarged
by the absorption of carbon abundantly provided by the plumbago coatings. The
return bends at the ends of the pipes never become red hot, and are thus not liable
to be injured.
The ends of the retort are closed by flat cast or wrought iron covers which are
perforated one for the passage of the inlet pipe and the other for the passage of the
outlet pipe.
The inlet pipe is connected by a pipe with a steam boiler and is provided with a
pipe through which the steam can be allowed to escape into the air. The inlet
pipe is also provided with a steam pressure gauge and a reducing valve to. make
the velocity and volume of the steam sent through the superheater absolutely
independent of the varying pressures shown at the boiler gauge the pipes being
provided with valves so that the steam can be readily controlled.
The outlet pipe is connected with a distributing chamber from which separate
pipes lead to the gas generating retorts of the bench. Each pipe is provided with
a valve which should be made of iron or steel, as brass or other composition metal
will give way under the temperature at which the superheated steam is allowed to
pass into the generators or gas retorts.
The distributing chamber is also provided with a test and gauge pipe having a
valve for ascertaining the heat and volume of steam issuing from the superheater
under a given pressure.
By this construction the breaking down of the heat in the gas generating retorts
and an interrupted or unsteady operation in the decomposition of the steam and
the making of the gas are avoided
All the supply and distributing pipes and their valves are covered and protected
against radiation and loss of heat, in a manner similar to the superheater pipes.
The distributing pipes at the rear end of the bench receive additional protection by
being surrounded by a polished sheet of tin, zinc, brass, copper, or iron to obstruct
any remaining tendency to radiation and to prevent the outside air from coming in
contact with the said pipes.
Each bench of retorts is provided with this arrangement for superheating and
distributing steam, and an apparatus for mingling the superheated steam with
hydrocarbon vapors and forming gas, so as to render the combined apparatus a
complete gas plant, adapted equally well to the smallest and the largest gas works.

page_text: 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
22nd November 1883.
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane, in the County of Middlesex Fellow of the Institute of Patent Agents.
"IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE OF GAS FROM LIQUID
HYDROCARBONS AND STEAM" A communication to me from abroad by Magnus
Gross, of the City, County and State of New York, United States of America.
The object of this Invention is to furnish for the purpose of making illuminating
or fuel gas from crude oil, naptha, or other liquid hydro-carbons and superheated
steam, an improved retort by the aid of which disassociation and readjustment of
the constituents of any liquid hydrocarbons and steam can be accomplished
simultaneously and in the nascent state, and a gas for lighting and heating will be
produced of from eighteen to thirty candle power, and so thoroughly fixed that it
will emit neither smell nor smoke while being burned, and which will require no
other purification but condensation and in which the per-centage of carbonic oxide
is completely under the control of the operator, and the formation of carbonic acid
or any explosive gas mixture is rendered impossible for the reason that the access
of atmospheric air is wholly prevented.
A further object of this Invention is to provide an improved steam superheater
for the purpose, First, of securing a thorough and uniform superheating of steam
for gas making or other purposes. Second of preventing steam or the products of
its decomposition from coming in contact with impurities. Third of avoiding the
use of extra fuel. Fourth of protecting the iron pipes in such a manner that the
superheater can be worked without interruption for a year or longer instead of
only a few months, before being rendered brittle and becoming used up. Fifth of
avoiding the reconstruction of a furnace and the consequent stopping of operations
while placing a new superheater. Sixth of saving so far as practicable all the
heat imparted to the steam and thus preventing the breaking down of the heat of
the retorts or generators through which the steam is led to be decomposed for
the manufacture of water gas or other purposes, and Seventh of thoroughly
controlling the velocity and volume of the steam passing through the superheater.
Whenever steam is used for the purpose of decomposition and the combination
of its elements, hydrogen and oxygen with other gaseous bodies, or in the
manufacture of water gas, the great hindrance to any such operation lies in the
fact, that the steam' in passing through retorts, generators or other apparatus
constructed for such purposes quickly lowers the heat required for the safe
conduction of such processes, rendering them intermittent and unreliable instead
of constant and uniform as they ought to be.
For the purpose of rendering the process of making gas from naptha or other
liquid hydrocarbons more perfect the apparatus about to be described which meets
the requirements and avoids the difficulties herein before mentioned as attending
the use of superheated steam has been devised.
In the drawings Figure 1 is a sectional side elevation of the improved retort
and a part of the bench. Figure 2 is a sectional plan view of the same taken
through the broken line x, x figure 1. Figure 3 is a sectional end elevation of the
same taken through the line y, y figure 2. Figure 4 is a rear elevation of the
improved superheater, shown as applied to a retort bench. Figure 5 is a front
elevation of a part of the same. Figure 6 is a sectional side elevation of the

page_text: superheater. Figure 7 is a sectional end elevation of the same. Figure 8 is a
sectional end elevation of one of the pipes enlarged to show its coverings.
In this apparatus the retort A is made open at both ends, and is divided
practically into three chambers, in the manner hereinafter described. The central
part of the retort A for about three fifths of its length, is exposed to the full heat
of the furnace B and is kept in a state of high incandescence, and is filled with
any convenient highly porous material. To the centre of the upper part of the
retort A is secured a piece of chamotte which projects downward several inches,
and serves as a flange or bridge to deflect in a downward direction all gases or
vapors that strike against it, and which may be replaced by a diaphragm having a
central opening if desired.
Into the retort A near its forward end and close to the porous material, is
hermetically fitted, a correspondingly shaped heavy cast iron plate D in the centre
of which is formed a circular aperture DI about four inches in diameter, through
which as an outlet, all gases must pass before they can enter the stand pipe E
attached to the mouth piece F in the ordinary manner. To this plate D may be
attached a basket G made of strong iron bars wherein to embed the porous
material in case it should be desired to use a combustible substance,-as coke for
instance, needing renewal every two or three months.. If the porous material
used be incombustible the retort need never be opened or the operation of gas
making interrupted, except for the purpose of repairing cracks.
The basket G is centred in the retort A by diaphragms O of chamotte or other
suitable material which have openings formed through them to receive and fit upon
the said basket. The forward diaphragm O, serves as a stop for the plate D, to
rest against and also as a cover to the joint between the said plate D and the
retort A. The rear diaphragm O, serves also as a flange to deflect the steam and
vapor into the incandescent material whether a basket be used or not.
The lower side of the forward end of the basket G is rounded or bevelled for
convenience in inserting it in the retort, and to the upper part of the retort is
attached a downwardly projecting flange P in such a position as to serve as a stop
for the basket G and as a deflector to cause the gases and vapor to enter and pass
through the incandescent porous material.
If fuel gas is to be made in any one of the retorts to serve as a feeder for the
bench or boiler furnace, or other purpose, the connection with the stand pipe E is
interrupted by closing the valve H placed in the said pipe and the gas is led to the
furnace or other place through the pipes I, J, attached to the bottom and side of
the mouth piece F. If the fuel gas is to go to a holder it is allowed to pass out
through the pipe K connected with and projecting horizontally from the stand
pipe E. The pipes I, J, K are provided with valves L, M, N, for controlling the
exit of the gas.
To the open rear end of the retort A is attached a cast iron mouth piece Q of
less weight and outward projection than the front mouth piece F. Through an
aperture in the centre of the upper part of the mouth piece passes the oil pipe R
and through an aperture in the lower part of the mouth piece passes the pipe S
for introducing superheated steam. These pipes R, S, are provided with valves
V W so that the amount of oil and steam delivered to the retort can be regulated
as desired. The inner end of the oil pipe R is curved downward so that the oil or
naphtha will drop upon hot perforated plates T made with upwardly projecting
rims, and supported by rods U or other suitable means in the middle rear part of
the retort A. The steam pipe S enters beneath the perforated plates T and its
inner end is bent to one side, so that the entering steam will strike the side of the
mouth piece Qor of the rear end of the retort A and will be thrown back, and made
to commingle with the vapor of the oil or naphtha formed by the contact of the
said oil or naphtba with the hot perforated plates T and with the still hotter steam.
The mouth piece Q is thickly coated with a non-conducting cement to prevent loss
of heat from radiation and the cooling effect of the outside air.
Thoroughly superheated steam, and the vapor of oil or naphtha intimately mixed,

page_text: in proper proportions are drawn by the action of a steam jet or exhauster placed
between the hydraulic and condenser through the length of the retort, which
becomes gradually hotter towards its centre. The retort is constantly filled with
an atmosphere of incandescent carbon, which causes the ready decomposition of the
steam into its elements. and the combination of the said elements in the nascent
state, with the highly heated vapours of the liquid hydro-carbon into a compound
of fixed combustible gases, consisting mainly of heavy hydro-carbons of the
ethylene series, the illuminators proper, of light carburretted hydrogen of the
methylene series of pure hydrogen, carbonic oxide, and a certain per centage of
the vapors of tar; no nitrogen, carbonic acid, ammonical or sulphurous compounds
or any other impurities being present or formed to pass out of the retort.
The porous material in the heated part of the retort, the bridge like projection
in the centre and the contracted outlet in the middle of the front plate D prevent
any of the vapors or gases from leaving the retort before having come in contact
with and passing through the incandescent porous material and thus becoming
thoroughly fixed, except such particles of tar as remain suspended in the hot gas
till the latter reaches the condenser and the tar drops out of the cooled gas, which
without any further treatment of any kind or manner is now fit for use.
To ensure permanency and uniformity in the operation of gas making by the use
of this improved retort the said retort should be placed in a bench, which should
have not less than six, and may contain as many as nine generating or distilling
retorts A figure 4 and in which is inserted an additional retort a open at both ends
for the purpose of housing the superheater. The forward part of this retort a rests
upon a double wall b c figure 6 and never becomes very hot. The rear part of
the retort a rests upon the rear wall d of the bench and upon a partition wall e
placed at a little distance from the rear wall d and ferming a chamber through
which the products of combustion pass from the main or furnace chamber to the
chimney and with which the interior of the retort a communicates by means of an
opening so that all rarified and highly heated air, spent fire gases, or vapors in.
the superheating retort a pass into the hot air chamber and thence to the chimney.
By this construction an even and uniform tension is maintained in the superheater,
and at the same time the possibility of a vacuum is avoided.
On the bottom of this retort a are placed four or five rows of pieces g of
chamotte or fire brick at equal distances apart and which are covered and the
spaces between them are filled to the depth of several inches with pulverized fire
clay h See figures 6 and 7. The retort is now ready to receive the superheater
proper which is constructed as follows:-
From twelve to fifteen lengths of wrought iron pipe i of double or triple the
ordinary thickness forming when connected a length of not less than one hundred
feet are connected at their ends by return bends j and the connected pipe is
provided at one end with an inlet pipe k and at the other end with an outlet pipe l,
which inlet and outlet pipes k, l, are only one third the diameter, of the super-
heating pipe . The lengths of pipe i before being connected by the bends ; are
carefully rubbed inside and outside with finely ground dry plumbago, till no more
will adhere to the iron. Pads of hair felt such as is used in covering boilers and steam
pipes are cut into strips m (see figure 8) two or three inches wide and half an inch
thick and are coated upon the inner surface with a thick paste made of plumbago and
warm water. The strips m thus prepared are wound around the pipes, i covering
them nearly to the screw threads that screw into the bends j. To the outer surface
of the wound strips m is applied strong but not too stiff asbestos paper cut into
strips n and thickly coated on the inner surface with the plumbago paste. The strips
of felt and asbestos paper are then secured in place by iron wire o wound around
them and the pipes i. The pipes i thus prepared and after being connected by the
return bends receive a final coating of a wash made of powdered plumbago fire
clay, and warm water. The parts of the superheater that are to be subjected to
incandescence are wrapped in 'sheets p of asbestos paper, coated inside and outside
with the same plumbago and clay paste, and secured in place by strong wire q

page_text: The superheater thus prepared is placed in position in the retort, and is
practically indestructible, since no fire-gases, hot air, or vapors that may be at any
time in the superheating retort, will attack the pipes, the carbonization of the hair
felt securing a free space into which the said pipes can expand as they are enlarged
by the absorption of carbon abundantly provided by the plumbago coatings. The
return bends j at the ends of the pipes i never become red hot, and are thus not
liable to be injured.
4
The ends of the retort a are closed by flat cast or wrought iron covers r which
are perforated one for the passage of the inlet pipe k and the other for the passage
of the outlet pipe l. The inlet pipe k is connected with a steam boiler by a pipe 8
and is provided with a pipe t through which the steam can be allowed to escape
into the air. The inlet pipe k is.also provided with a steam pressure gauge u and
a reducing valve to make the velocity and volume of the steam sent through
the superheater absolutely independent of the varying pressure shown at the boiler
The pipes k, s, t, are provided with valves w so that the steam can be
guage.
readily controlled.
The outlet pipe is connected with a distributing chamber a from which separate
pipes y lead to the gas generating retorts A of the bench. Each pipe y is provided
with a valve z which should be made of iron or steel, as brass or other composition
metal will give way under the temperature at which the superheated steam is
allowed to pass into the generators or gas retorts A. The distributing chamber a
is also provided with a test and gauge pipe y¹ having valve 2¹ (see figure 4) for
ascertaining the heat and volume of steam issuing from the superheater under a
given pressure.
By this construction, the breaking down of the heat in the gas generating
retorts A, and an interrupted or unsteady operation in the decomposition of the
steam and the making of the gas are avoided.
All the supply and distributing pipes and their valves are covered and protected
against radiation and loss of heat, in a manner similar to the superheater pipes i.
The distributing pipes y at the rear end of the bench receive additional protection
by being surrounded by a polished sheet of tin, zinc, brass, copper or iron to
obstruct any remaining tendency to radiation, and to prevent the outside air from
coming in contact with the said pipes.
Each bench of retorts is provided with this arrangement for superheating and
distributing steam, and an apparatus for mingling the superheated steam with
hydro-carbon vapors and forming gas so as to render the combined apparatus
a complete gas plant adapted equally well to the smallest and the largest gas
works.
Having described the nature of the said Invention and the manner of performing
the same I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is :
1 A retort for gas making made substantially as herein shown and described
with plates to distribute the oil or naphtha, a downwardly projecting flange for
deflecting the gases and vapors downward, a porous material and a front plate
having central aperture, whereby all the gases and vapours will be made to
pass through the porous material before reaching the front of the retort, as set
forth.
2ndly In a retort for gas making, the combination with the retort A, the oil
pipe R, and the steam pipe S, of the perforated plates T, substantially as herein
shown and described, whereby the oil or naphtha is distributed and made to
thoroughly commingle with the superheated steam as set forth
3rd A steam superheater constructed substantially as herein shown and described
and consisting of a retort a, having top opening f and the lengths of pipe i, connected'
by return bends coated with plumbago, covered with strips of hair felt and asbestos
paper coated with a plumbago paste and secured in place by wire, and the inlet'
and outlet pipes k, l, of a smaller diameter than the main pipes, as set forth.
4th The mode of protecting the pipes of a steam superheater, substantially as

page_text: herein shown and described, which consists in coating the pipes inside and outside
with dry plumbago, covering the pipes singly with strips of hair felt coated upon
the inner side with plumbago paste, covering the felt with strips of asbestos paper
coated upon the inner side with plumbago paste and washed upon the outerside with
a mixture of plumbago, pulverized fire clay, and water, securing the hair felt and
asbestos paper in place with wire and covering the collection of pipes with asbestos
paper coated upon both sides with the clay and plumbago paste, and secured in
place by wires as set forth.
5th In a steam superheater, the combination with the retort a and the pipes i, of
the pieces g of fire brick, and the pulverized fire clay h substantially as herein
shown and described whereby the superheating pipes are kept out of contact with
the retort as set forth.
6th In a steam superheater, the combination with the inlet pipes k of a steam
pressure gauge u and a reducing valve substantially as herein shown and
described, whereby the velocity and volume of the steam sent through the super-
heater can be made independent of the varying pressure shown at the boiler, as set
forth.
In witness whereof I the said Alexander Melville Clark, have hereunto set my
hand and seal this Twentyfirst day of November A.D. 1883.
A аг CLAD17