IMPROVEMENTS IN THE PROCESSES OF AND APPARATUS FOR SUPERHEATING STEAM, AND MAKING HEATING AND ILLUMINATING GAS
Year: 1878

page_text: LETTERS PATENT to Bristow Hunt, of Serle Street, Lincoln's Inn, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN THE
PROCESSES OF AND APPARATUS FOR SUPERHEATING STEAM, AND MAKING
HEATING AND ILLUMINATING GAS." A communication from abroad by Thadeus
Sobienski C. Lowe, of Norristown, Pennsylvania, Engineer, and George Spring
Dwight, of Mount Clair, New Jersey, Engineer, both places being in the
United States of America.
COMPLETE SPECIFICATION filed by the said Bristow Hunt at the Office of
the Commissioners of Patents on the 14th January 1878.
BRISTOW HUNT, of Serle Street, Lincoln's Inn, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN THE PROCESSES OF AND APPARATUS FOR SUPER-
HEATING STEAM, AND MAKING HEATING AND ILLUMINATING GAS." A communica-
tion from abroad by Thadeus Sobienski C. Lowe, of Norristown, Pennsylvania,
Engineer, and George Spring Dwight, of Mount Clair, New Jersey, Engineer, both
places being in the United States of America.
Heretofore the manufacture of what is known as "wator gas" for heating and
illuminating purposes has been practically unsuccessful, on account of the variable
quality of the product, the excess of carbonic acid found, the strain upon the
apparatus involved by the heat required to obtain the best result, and the difficulty
of producing the gases rapidly.
By the improved processes and apparatus herein-after fully described these
difficulties are overcome in such a manner as that the said gases are produced more
economically for business purposes.
In order to explain this Invention as completely as possible I will now proceed
to describe the best apparatus with which the Inventors are acquainted for carrying

page_text: the same into practical effect, reference being had to the illustrative Sheets of
Drawings hereto annexed, and to the figures and letters of reference marked
thereon, respectively as follows :-
On the accompanying Drawings,—
Figure 1, Sheet 1, represents a vertical section of the apparatus for producing
heating gases; and Figure 2 is a plan view thereof.
Figure 3 is a vertical section of a modification of the apparatus shown in Figures 1
and 2; and Figure 4 is a plan view thereof.
Figure 5, Sheet 2, is a vertical section of the apparatus adapted to the making of
illuminating gases; and Figure 6 is a plan view thereof.
And Figure 7, Sheet 3, is a section of a modification of the apparatus shown in
Figures 5 and 6; and Figure 8 is a plan view thereof.
Referring to Figures 1 and 2, Sheet 1 of the Drawings, A is the gas generator,
which consists of a casing B, made of boiler iron or other suitable material, and
lined with fire-bricks C or other suitable refractory materials, a space between the
casing and the lining being filled with some suitable non-conducting material.
Beneath the grate E of this generator is an ash-pit D, into which a pipe F leads
for the admission of steam, preferably highly heated, and a pipe G for the admission
of a blast of air, also preferably highly heated. At the top of the generator A, or
in any other convenient position, is placed a hopper H, provided with a closely
fitting bell or cone shaped valve O¹, counterbalanced as shown, and also a closely
fitting lid I. At or near the base of the generator is a closely fitting door, com-
municating with the ash-pit D, and the chamber above the grate E, which can be
withdrawn for the purpose of cleaning the ash-pit, removing clinkers, and adjusting
the grate bars. The upper part of the generator is also provided with a pipo K, at
the bend or bends of which closely fitting lids or caps a are provided, with suitable
fastenings, for the purpose of gaining access to the pipe to clean the same.
L is a
stack, consisting of a casing of iron V or other suitable material, lined with fire-
bricks or other suitable refractory materials U, the enclosed space being filled with
loosely laid fire-brick or other suitable refractory materials, resting on a perforated
arch T of like material. At the bottom of the stack L is a combustion chamber T,
into which the pipe K of the generator A leads; and also an air pipe S for the
admission of a blast of air, preferably highly heated. The top of this stack is pro-
vided with an opening J leading into the chimney, in which is a heat restorer N,
which consists of an ordinary iron stack of increased dimensions, with heads O at
top and bottom, in which heads are inserted ordinary boiler tubes. P is a tube
through which the air is forced into the heat restorer N. The atmospheric air
which circulates around the tube issues out at the lower end of the heat restorer in
a heated condition, thence passing through a tube R, which joins the pipes G and S
leading to the ash-pit of the generator A and to the combustion chamber T of the
stack L to support combustion in the same. The stack L is also provided with a
valve, which is shown on the Drawing as a safety valve, consisting of a suitably
weighted cup M, resting in a liquid seal, which is fed automatically or otherwise,
said cup being raised automatically to allow the escape of the gases if an increased
pressure should arise in the stack L; an ordinary valve may however be employed
instead of this. Access is had to this cup, which is suitably counterbalanced to raise
and lower it when it is desired to open or close the opening J, through a lid 0%,
hinged to the chimney. W is a tube for conveying the resulting gases from the
stack L to an upright tubular boiler, with chambers Y and Z at the top and bottom
respectively; and Q is a pipe for conveying the cooled gases from the chamber Z to
any suitable holder.
When it is desired to put this apparatus into operation a fire is built on the
grate E in the generator A, and the cup M of the stack L is raised out of the liquid
seal to allow of the free escape of the waste products of combustion through the
brickwork or other refractory material in the stack L, and up through the tube in
the heat restorer N. Any suitable solid carbonaceous substances, preferably anthracite

page_text: or bituminous coal or coke, besides which however may be mentioned any kind of.
wood, all kinds of woody rubbish, finely cut straw, coal dust or slack, asphaltum,
or any material capable of generating heat, is then gradually introduced into the
generator A. In the meantime a fan blower or other suitable apparatus is caused
to force air through the pipe P into the heat restorer N, from which a sufficient
quantity of warmed or heated air is admitted through the tubes R and G to cause
moderate combustion on the grate surface of the generator A. As the thickness
of fuel increases in the generator A, and while it is being brought into an incan-
descent state, the carbonic acid which is caused by the union of oxygen and carbon
at the bottom of the generator will pass up through the thickness of incandescent
fuel, become re-carbonized, and be thus converted into carbonic oxide. This highly
inflammable gas in union with the sulphur of the coal, if that is used, and other
impurities thrown off by the heat, leaves the generator A through the pipe K, and
is discharged into the combustion chamber T, preferably heated air at the same time
being admitted through the pipe S into the same chamber. A flame results, pro-
ducing an intense heat, which passing up through the openings in the arch T¹ and
heats to bright redness or white heat the entire mass of enclosed open brickwork.
or other refractory material from bottom to top. In the meantime considerable
heat which ascends through the open tubes of the heat restorer N, being carried in
the waste products of combustion, is absorbed by the air, which is forced in an
opposite direction down the heat restorer, around the tubes, and is returned to the
lower ends of the generator A into the ash-pit D and the combustion chamber T for
supporting the combustion in the same, thus lessening the length of time and
amount of fuel to produce the necessary heat in the different chambers, the waste
products of combustion escaping through the opening J.
After the mass of fuel, several feet more or less in thickness, in the generator A
has become thoroughly incandescent, the refractory material of the stack L will
also have become highly heated by the combustion of the otherwise waste gases
passing from the generator A. The air is then shut off from both the ash-pit D
and the combustion chamber T, the cup M is lowered into its seal, the valve in the
pipe W is opened, and steam, preferably superheated, from the boiler X or else-
where, is admitted into the ash-pit D, and passing up through the incandescent
coals, where, coming in contact with the highly heated carbon gas, the decomposition
of the same immediately takes place, liberating the hydrogen and carbonic oxide,
which gases pass together through the pipe K into the combustion chamber T, and
up through the mass of heated refractory material therein contained and are therein
fixed, and then pass out through the pipe W at the top of the stack, enter the
chamber Y at the top end of boiler X, whence they pass down through the nume ous
tubes contained in said boiler to assist in generating and superheating the steam
therein. The gases, now considerably cooled, leave the tubes and enter the chamber
Z, and thence through tube pass to a proper receptacle or place of consumption.
After a time, and when a large quantity of gas has been produced and stored, the
heat will be so much reduced in both the stack L and generator A that carbonic
acid will be given off, which can be determined by means of a test cock in the pipe W,
and the application to the escaping gases of any common and well-known means
for determining this.
Whenever it is desired to restore the heat to the fuel in the generator A and the
stack L preparatory to generating heating gases again it is necessary to remove the
closely fitting lid I and open the valve O to permit the burning of the highly
inflammable carbonic oxide and hydrogen in the upper portion of the generator A,
and from the stack L, to prevent explosion, which might ensue if they remained in
the generator when air was again admitted. The steam is then shut off, and the
cup M is raised out of its seal, atmospheric air is again forced into the ash-pit D
and combustion chamber T, as before described, and now a few minutes of time
suffice to bring both chambers to the required heat, after which a large amount of
gas is again produced as before.

page_text: As soon as the generator A has been re-heated in the same manner as it was
originally heated the process is again continued, and heating gas is again evolved.
Where the steam is at a lower temperature than the incandescent inass in the
generator it is proferable to admit it above the grate E, in order to prevent
extinguishment of the combustion upon the grate surface, which might occur if it
was admitted into the ash-pit D at such temperature.
By means of the hopper H and valve O¹ a sufficient quantity of fuel can be
introduced into the generator A to enable the process just described to be repeated;
or this hopper and valve can be dispensed with, the close fitting lid being attached
directly to the generator, and removed to admit the proper fuel or allow the exit of
the inflammable gases, as described.
At
Figures 3 and 4 of the Drawings show a modification of the apparatus for
carrying out the process just described, provided with means for economically
superheating the steam. This consists of a superheater L¹, formed of a casing of
iron or other suitable material V₁, lined with fire-brick or other suitable refractory
material U¹, the enclosed space being filled with loosely laid fire-bricks or other
suitable refractory materials, resting on a perforated arch T2 of like material.
the bottom of the superheater L' is a combustion chamber T3, and at its top is an
opening J, controlled by a safety or other valve, such as that with which the stack L
is described as being provided ; or the waste products may escape into a heat
restorer, connected by suitable pipes with the ash-pit D and combustion chamber,
as before described, and with the combustion chamber T3 of the superheater by a
pipe S¹. The products of combustion from the generator A are distributed by the
pipes K, K1, K2, the stack L and superheater L'. As soon as the entire mass of
refractory material in both the stack L and the superheater L' has been heated to
white or suitable heat by the products of combustion coming in contact with the
same the waste products escaping through the openings J, J', the valve in the pipe K
is closed, and steam is admitted through pipe F into the superheater L' (the cup M
having been lowered into the seal), and passes through the refractory material into
the combustion chamber T³, and out through the pipe F¹ into the generator A,
when the process previously described is carried on.
When the beating gas produced by the apparatus shown in either Figures 1 and 2
or Figures 3 and 4 of the Drawings is to be used in dwellings or buildings a small
quantity of hydrocarbon may be introduced into the generator A, so that the gas
when produced will have an odour by which, if there should be an escape, its
presence could be readily detected.
In Figures 5 and 6, Sheet 2, is shown an apparatus for producing illuminating
gas. This shows the same apparatus as that shown in Figures 1 and 2, for pro-
ducing heating gases, with the following additions:-A tank P¹ is provided for
holding petroleum or other hydrocarbon oils, with a pump 02 for forcing the same
as required into an elevated tank F2, from which a pipe conveys the liquid hydro-
carbon to a funnel I' forming part of a tube, having a double bend before entering
the generator A, so as to form a seal and prevent the escape of the gases in said
generator, or the communication of fire. It is better to have two or more of these
pipes located at different parts of the generator to equally distribute the liquid
hydrocarbons. The tube Q conveys the gases from the chamber Z to a washer A',
in which latter is or may be an inclined diaphragm H¹, rough or corrugated on its
under side. B¹ is a tube, conveying the gases from the washer A' to a scrubber C¹,
which is of the ordinary kind, filled with coke or other suitable material, and from
which the gases are conveyed into the holder E¹ or other point of storage, or
directly to any place of consumption by a tube D'. G' is a well for catching con-
densed oils or tar should any exist after leaving the generator.
This apparatus is put in operation in exactly the same manner as that described
in Figures 1 and 2, and as soon as the fuel in the generator has become thoroughly
incandescent, and the refractory material of the stack L has become highly heated
or white hot, the steam (preferably superheated) is admitted into the generator at

page_text: the same time that liquid hydrocarbon is admitted into the same in regulated
quantities from the tank F, and into the funnel I', whence passing in through the
curved pipe or pipes it drops directly on to the hot coals in the generator A. Here
the liquid hydrocarbon is immediately volatilized into a thick vapor, and at this
point the highly heated hydrogen continually emerging from the top of the coals
instantly, and before having time to loose any heat, intermingles with and thoroughly
permeates every particle of the volatile carbon, which has the effect of separating
and subdividing the particles or globules of carbon, and of surrounding them
uniformly with the proper proportion of hydrogen, so that the particles of carbon
not being able to come in contact with each other are rendered entirely non-
condensible, as has been proved by numerous experiments and long experience.
These mixed gases pass through the pipe K to the bottom of the stack L, and up
through the mass of highly heated refractory material, whereby every portion of
the gas coming in contact with the highly heated refractory material is thoroughly
fixed. These mixed gases in their highly heated condition are carried off through
the pipe W at the top of the stack, enter the chamber Y at the top end of the
boiler X, where they pass down through the numerous tubes of the boiler to assist
in generating and superheating the steam therein. The gases now considerably
cooled leave the tubes and enter the chamber Z, and thence through tube Q pass
into the washer A¹, under the inclined diaphragm H' under water, in which any
soot, dust, or other impurity is deposited. From the washer the gas next enters
the lower end of the scrubber C¹, and after passing up through the contents thereof
is conveyed through the tube D¹ to the holder E³, or other point of storage, or
directly to any place of consumption.
While generating gas, as before described, a test burner will readily indicate the
quality or candle power of the gas being produced, and the requisite carbon or
hydrogen can be easily regulated by regulating the quantity of liquid hydrocarbon,
or of steam, admitted to the generator A.
After a time, and when a large quantity of gas has been produced and stored,
the heat will be so much reduced in both the stack L and the generator A that
the steam will no longer decompose, although both the stack and the generator will
still retain a dull red heat, the non-decomposition of the steam being at once
detected by the indication of carbonic acid gus at the test cock before alluded to,
or by the smokiness of the flame at the test burner, which, for want of hydrogen,
gives a thick, dark red, smoky flame through an ordinary four or five foot burner.
Such gas is known as petroleum gas, and condenses rapidly in consequence of
not being mixed with the proper proportion of hydrogen, in the manner above
described.
Whenever it is desired to restore the heat to the fuel in the generator A and in
the stack L, the liquid hydrocarbon and steam are both shut off, the closely fitting
lid I is removed, the valve O' is opened, and the mixed gases in the generator and
in the stack are allowed to burn in the atmospheric air, which, unless this was
done, would become explosive on the re-application of the air. The valve O is
opened, and fuel is then added, if necessary, through this opening. The lid is then
properly secured, air is again forced into the ash-pit D and combustion chamber T,
as before described, and a few minutes of time suffice to bring both the generator A
and the stack L to the required heat, after which a large amount of hydrocarbon
gas is again produced as before.
When a steady flow of gas is desirable two sets, or more, of generators may be
employed, according to the requirements.
The resulting gases may be passed through and caused to generate steam in one
boiler C.
One heat restorer N can be made to carry off the hot waste products of combus-
tion from several or all of the generators and stacks, and thus serve to heat the air
which is to support combustion in each, thus accomplishing the heating with much
rapidity and economy.

page_text: Instead of employing oils in the carbonizing process, as above described, other
substances containing volatile carbon may be employed, such as rich bituminous
coal, rosin, cotton seed, ordinary coal, tar, asphaltum, fats of all kinds, and residuum
from oil refiners. Care however should be taken when using any kind of solid
carbon that the same is evenly spread on the top surface of the heated fuel or other
material in the generator A in such a manner that the hot gases while emerging
from the top of this hot fuel will come into contact with such solid or lumpy carbon,
and thereby assist in its volatilization.
In the case of using bituminous coal it would be desirable to use some additional
volatile carbon oil to add to the hydrogen being generated from the steam.
If impure carbons are used for carbonizing the hydrogen the usual purifiers
will be necessary, but when petroleum and other pure carbons are employed a
purifier is not required.
The principal advantages gained by passing the mass of gases from generator A
through the highly heated refractory material in the stack L is a more thorough
decomposition of the elements which are converted into fixed gases by being sub-
jected to a higher heat, such as the stack contains.
Figures 7 and 8, Sheet 3, show the apparatus described in Figures 5 and 6, with
the addition of a superheater of steam similar to that described with reference to
Figures 3 and 4, its operation being substantially the same as that described with
reference to Figures 3 and 4.
As the material which is highly heated is a refractory one, incapable of oxidation
in the superheater shown in Figures 3 and 4, 7 and 8, the steam when superheated
will be free from oxidation, and may be used-for-any well-known purposes in the
useful arts.
The apparatus as shown in all the Figures may be successfully used without the
boiler X and heat restorer N, the steam being formed in a distinct generator, and
the air being heated in a distinct heater if necessary or desirable.
The heat restorer N may, instead of serving to heat the air blast, as before
described, be used as a boiler for generating steam, and may either remain in the
position shown, or be set adjacent to the stack L or superheater L', where the hot
waste products of combustion may be conveyed to it in the proper manner.
In some instances the stack L may be dispensed with and the superheater L¹
employed, the steam being passed through the same directly to the generator A,
from which the resulting gases pass to the proper receptacle for use.
In cases where gas extremely rich in carbon is desired the same will be best pro-
duced by omitting the steam and generating the gas from liquid hydrocarbons
alone, and using the generator A either alone or in conjunction with the stack L.
The forms of apparatus which may be used in carrying the above-described
improved processes are various, but the forms shown are preferred, they being in
every respect simple and easy of management.
Either heating or illuminating gas, as the one or the other is formed, may be
employed to re-heat the stack and superheater if desirable.
Other common and well-known means and methods than those described and
shown may be employed for cooling and purifying the gases produced.
Heretofore in the generation of water gas it, has been very difficult to obtain
uniform results on account of the constantly changing condition of the heat in the
generator, which is steadily reduced by the continued introduction of the steam
into the incandescent coal. By the method herein employed the intense heat
evolved during the firing-up process and fixed in the mass of refractory material
contained in the stack is not greatly reduced by the entrance therein of the hot
gases passing over from the generator, and by its uniformity and intensity serves
not only to render then thoroughly permanent, but compensates the unequal action
of the generator and equalizes the result.
In the manufacture of gases into which carbon enters much annoyance and
expense has been occasioned by the deposit and incrustations caused by this element,

page_text: which fastens upon and clogs up the retorts and connecting pipes. The mechanical
construction of the interior of the stack, consisting as it does of loosely laid refractory
material, presenting irregular surfaces and openings, while allowing a passage for
the gases arrests the particles of soot or fixed carbon, and detaining them in the
crevices and chinks they are subsequently, on the re-application of the blast, burned
therein, contributing heat to the stack, thus producing an economic result, and
disposing of a very troublesome element in gas making.
Having now described the nature and objects of the said Invention, together
with the manner in which the same is to be or may be performed or carried into
practical effect, I would remark in conclusion that I claim as the Invention com-
municated to me by the above-mentioned Thadeus Sobienski C. Lowe and George
Spring Dwight,—
1. The process of manufacturing heating gas which consists in the introduction
of steam, superheated or not, into a mass of coal or other carbonaceous substance or
substances in a state of incandescence in a close chamber, previously heated by
direct internal combustion, and then for the purpose of fixing the gases of said
chamber and making them uniform, passing them from said chamber into and
through a second chamber, previously heated by internal combustion.
2. The process of manufacturing heating gas, which consists in the introduction
of steam, previously superheated, in a chamber heated by internal combustion
into a mass of coal or other carbonaceous substance or substances in a state of
incandescence in a close chamber, previously heated by direct internal combustion,
and then for the purpose of fixing the gases of said chamber and making them
uniform, passing them from said chamber into and through a second chamber, pre-
viovsly heated by internal combustion.
3. The introduction of a small quantity of hydrocarbon oil or other odourous
substance into the chamber where the heating gases are produced, in order that the
lattor when fixed and ready for use may have an odour by which their presence
can be detected if they should escape.
4. The process of manufacturing gas, which consists of dropping or otherwise
admitting in limited quantities, continuously or intermittently, hydrocarbon oils or
other carbonaceous substances, liquid or solid, on to the top of a thick mass of coal
or other carbonaceous substance in a state of incandescence in a close chamber
previously heated by direct internal combustion, with or without the introduction
of steam, and then, for the purpose of fixing the gases of said chamber and making
them uniform, passing them from said chamber into and through a second chamber,
which also has been previously heated by direct internal combustion.
5. The process of manufacturing illuminating gas which consists in the introduc-
tion of steam previously superheated in a chamber heated by internal combustion
into and through a mass of coal or other carbonaceous substance in a state of
incandescence, in a close chamber, previously heated by direct internal combustion,
into which limited quantities of hydrocarbon oils or other carbonaceous substances,
liquid or solid, are admitted, by dropping or otherwise, on to the top of said mass
of coal or substance, and then, for the purpose of fixing the gases in said chamber
and making them uniform, passing them from said chamber into and through
a second chamber, which also has been previously heated by direct internal
combustion.
6. The process of superheating steam by introducing it and passing it through a
chamber filled with refractory material, previously heated by direct internal com-
bustion, all substantially as herein-before described.
7. The combination, application, and use of the improved apparatus for generating
heating gas.
8. The combination, application, and use of the improved apparatus for generating
illuminating gas.
And, 9. The combination, application, and use of the improved apparatus for

page_text: superheating steam, all substantially as herein-before described, and as illustrated
on the accompanying Sheets of Drawings.
In witness whereof, I, the said Bristow Hunt, have hereunto set my hand and
seal, this Fourteenth day of January, in the year of our Lord One thousand
eight hundred and seventy-eight.
BRISTOW HUNT. (LS.)