IMPROVEMENTS IN THE MANUFACTURE OF ĜAS FOR BURNING.
Year: 1874

page_text: LETTERS PATENT to Thomas Boverton Redwood, of Fairlawn, Finchley,
in the County of Middlesex; for the Invention of "IMPROVEMENTS
IN
THE MANUFACTURE OF ĜAS FOR BURNING.
Sealed the 17th November 1874, and dated the 26th September 1874.
PROVISIONAL SPECIFICATION left by the said Thomas Boverton
Redwood at the Office of the Commissioners of Patents, with his
Petition, on the 26th September 1874.
I, THOMAS BOVERTON REDWOOD, of Fairlawn, Finchley, in the County
of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF GAS FOR BURNING," to be as
follows:-
This Invention has for its object improvements in the manufacture of
gas for burning.
I produce a permanent hydrocarbon gas rich in carbon from petroleum
or other liquid or solid hydrocarbon by subjecting the vapour of such
hydrocarbon to a regulated heat applied through the medium of copper

page_text: or other good conductor of heat, arranged so as to present as large a
heating surface as possible; or I introduce the vapour of petroleum or
other liquid or solid hydrocarbon as aforesaid into an atmosphere of the
vapour of water, or of water gas or other suitable gas previously heated
to a temperature at which the hydrocarbon vapour is resolved wholly or
partially into permanent gas rich in carbon.
I mix or dilute the hydrocarbon gas produced as above with water gas or
other gas deficient or less rich in carbon than the hydrocarbon gas itself
is, so as to form a mixture suitable for the purpose for which it is
intended.
I introduce into either of the gases produced in the manner described,
the vapour of petroleum or other liquid and volatile hydrocarbon to be
retained there in the state of gaseous diffusion.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Boverton Redwood in the Great Seal Patent
Office on the 25th March 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BOVERTON REDWOOD, of Fairlawn, Finchley, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of September, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Thomas Boverton Redwood, Her
special license that I, the said Thomas Boverton Redwood, my exccutors,
administrators, and assigns, or such others as I, the said Thomas Boverton
Redwood, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man,
an Invention for "IMPROVEMENTS IN THE MANUFACTURE OF GAS FOR BURNING,"
upon the condition (amongst others) that I, the said Thomas Boverton

page_text: Redwood, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Boverton Redwood, do
hereby declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say :—
This Invention has for its object the production of a permanent gas
rich in carbon from petroleum and other hydrocarbon oils, including the
oils obtained from coal, shale, peat, and other sources. As met with in
commerce these oils often contain solid hydrocarbons such as paraffin;
they are mixtures in various proportions of several proximate constituents
differing in density and volatility, but consisting for the most part of
carbon and hydrogen in proportions which in some of their constituents
accord with, and in others differ but slightly from those in which the
same elements exist in olefiant gas or other permanent hydrocarbon
gases which are the most valuable light producing constituents of the
richest and best description of coal gas or of gas suitable for burning as
a source of light. I produce from this class of oils a permanent gas not
a mere vapour, which gas is rich in carbon, and well suited for burning
as a source of light when it has been diluted with other combustible
gases that are less rich in carbon, or that do not themselves burn with a
sufficiently luminous flame. .
It has long been known that by the application of heat the hydro-
carbon oils, such as I have alluded to, may be made to yield a gas
tolerably rich in carbon, but hitherto the processes adopted for that
purpose have not afforded uniform and satisfactory results, the gas
produced being generally deprived of part and sometimes of the principal
part of the carbon contained in the oils by the action of the heat applied
in the process.
The principal difficulty experienced in getting a good permanent gas
rich in carbon from hydrocarbon oils, has been that of so regulating and
applying the heat as to ensure the conversion of the oils or their vapours
into permanent gas without at the same time causing much of the

page_text: carbon, which is the true source of light during the combustion of gas,
to be deposited in a solid state.
It is necessary to apply a temperature
above that of visible redness in order to change the vapour of the oil
into permanent gas, and there appears to be but a small range of
temperatures through which that change can be effected in contact with
most solid substances, without converting part of the oil into a species
of tar and at the same time causing a deposition of solid carbon from the
gaseous product.
Now my Invention consists of a method or methods by which the
liquid hydrocarbons alluded to, or their gaseous products, may be
subjected to a higher temperature than it has hitherto been found
practicable to apply to them without causing a deposition of solid
carbon, and the range of temperatures at which the conversion of the
oils into permanent gas without loss of carbon takes place is thus
enlarged, so that a more uniform and satisfactory result may be
practically obtained and an important economy effected.
I bave found that the liquid bydrocarbons or their vapours when
hcated in contact with metallic copper or an alloy of copper, such as
brass or gun metal, will bear the application of a higher temperature
than can be applied to them by contact with other substances without
depositing solid carbon, and on this fact partly my improved processes
for the production of gas for burning are founded.
I have also found that if the liquid hydrocarbons or their vapours be
introduced into a hot chamber together with a permanent gas, such as
water gas, which is cither previously or immediately heated to a
temperature which in a metal or other solid body would be represented
as that of bright redness, the vapours of the hydrocarbon oils may under
these circumstances be subjected in contact with copper or an alloy of
copper to a cherry red heat, and will thus be more completely and
satisfactorily converted into a permanent gas than would otherwise be 3
the case.
My improved processes for the manufacture of gas for burning are
founded upon the foregoing facts.
I produce a permanent hydrocarbon gas, rich in carbon, from petro-
leum or other liquid or solid hydrocarbons, such as I have described, 3

page_text: by subjecting the vapours of such hydrocarbons to a bright red heat
applied through the medium of copper or an alloy of copper, such as
brass, and this is effected by introducing the hydrocarbon oil or its
vapour gradually and continuously as the conversion takes place, into a
red hot cylinder or converting chamber composed of copper or an alloy
consisting principally of copper filled with scraps, or turnings, or wire,
or wire gauze of the same metal, so arranged as to conduct the heat as
equally as possible to every part of the chamber, and to present as large
a heating surface as possible to the vapour. In this way a temperature
of bright redness may be applied without causing any material deposition
of carbon from the gas produced, which will consist largely or principally
of olefiant gas or of other gas or gases, rich in carbon, and which may
be diluted with water gas or other gas which is not rich in carbon, to
render it suitable for use as a gas for burning as a source of light. But
although the vapours of liquid or solid hydrocarbons such as I have
described may, if due care be exercised, be converted into permanent gas
with little or no deposition of carbon by the method already described,
I prefer to effect the conversion with the intervention of water gas by the
following method :-The water gas I use is obtained by the well known
process of passing superheated steam over the surface of incandescent
carbon, at a high temperature, when a mixture of hydrogen gas and
carbonic oxide is produced together with some carbonic acid which is
removed by means of slaked lime before using the gas. The purified
water gas so produced is introduced simultaneously with the hydrocarbon
oil or its vapour into the cylinder or converting chamber constructed,
filled, and arranged as already described in the process for making gas
without the intervention of water gas, but in this case the cylinder and
its contents may be maintained at a higher temperature, usually called
a cherry red heat, and in order to prevent too great a reduction of
temperature by the introduction of the water gas, I convey this gas
through red hot tubes before it enters the cylinder or converting cham-
ber. The proportion of water gas used in this process in relation to the
hydrocarbon oils may be regulated by suitable valves or taps so as to
yield a mixed gas having an illuminating power such as may be required
for burning as a source of light or otherwise, it may be further mixed
with a richer gas made without or with a smaller quantity of water gas,
or with water gas itself.
fillon nundued by this on her £1.

page_text: sulphur, a little sulphuretted hydrogen would be formed, which as well
as any carbonic acid that may be present must be removed from the
water gas, and for this purpose it will be desirable to have a layer of
oxide of iron, such as is commonly used in gas purification, at the
bottom of the lime purifier by which the carbonic acid is to be taken
out. The water gas thus produced and purified may be used at once or
stored in a gasometer for use.
The conversion of hydrocarbon oils into permanent gas, either with or
without the intervention of water gas, may also be effected in a gas
retort if this be lined inside with copper, or an alloy of copper filled
with scraps, turnings, wire, or wire gauze of the same metal, and pro-
vided with the means of introducing a regulated supply of the hydro-
carbon oils, and when required of water gas. The exit pipe by which
the gas is conveyed away from the hot cylinder or retort to the extent
to which such pipe is exposed to a strong heat should be of the same
material as the cylinder or its inner surface, or otherwise some of the
gases richest in carbon may be decomposed when subjected to a high
temperature, and deprived of part of their carbon and to a corresponding
extent of their light producing power.
If the arrangements of existing gas works be not utilized or adopted,
cylinders may be used of any convenient size or form, in which however
it is desirable to provide for the means of heating them throughout to
the required extent, and these cylinders may be either made entirely of
copper or an alloy of copper, or they may have an outside covering
of other material to protect the metal within from the destructive effects
of the fire.
When previously heated water gas is used in the process, the fire by
which the cylinder or converting chamber is heated may be made to
heat pipes, through which the water gas is conveyed to the hot chamber,
and it will be found advantageous for the preservation of these pipes
that they should be imbedded in and surrounded by powdered lime to
prevent their oxidation and destruction from this cause.
In fitting up apparatus specially for the purpose of making gas by the
processes herein described, it will be found advantageous to have the
condensing and oil separating arrangements at a higher level than that
of the converting cylinders, so that the oil that is condensed and

page_text: separated from the gas after leaving the converting cylinder may be
brought back to the cylinder by its own gravity.
What I claim is, the manufacture of a permanent gas, rich in carbon,
by bringing the vapour of a suitable hydrocarbon into contact with
copper or an alloy of copper kept in a highly heated state and arranged
so as to expose a large extent of surface, substantially as described.
I also claim the manufacture of a permanent gas, rich in carbon, by
bringing the vapour of a suitable hydrocarbon together with water gas
into contact with copper or an alloy of copper kept in a highly heated
state and arranged so as to expose a large extent of surface, substantially
ȧs described.
In witness whereof, I, the said Thomas Boverton Redwood, have
hereunto set my hand and seal, this Twentieth day of March, in
the year of our Lord One thousand eight hundred and seventy-
five.
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