IMPROVEMENTS IN THE MANUFACTURE OF GAS
Year: 1875

page_text: LETTERS PATENT to Thomas Boverton Redwood, of Fairlawn, North
Finchley, in the County of Middlesex, for the Invention of
PROVISIONAL SPECIFICATION left by the said Thomas Boverton
Redwood at the Office of the Commissioners of Patents, with his
Petition, on the 29th July 1875.
I, THOMAS BOVERTON REDWOOD, of Fairlawn, North Finchley, in tho
County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF GAS," to be as
follows.-
-
This Invention has for its object to improve the quality and increase
the quantity of gas obtained by distilling coal in retorts as now usual.
For this purpose I pass the gas as it issues from the retort through a
heated cylinder or retort of copper or alloy of copper, filled as described
in the Specification of a former Patent dated 26th September 1874,

page_text: No 3307, granted to me, with scraps, turnings, wire, or wire gauze of
the same metal By this means the hydrocarbon vapours which are
carried off with the gas as it issues from the retorts, and which at the
present time are condensed in the condensers, are converted into a per-
manent gas, rich in carbon, thereby not only increasing the quantity of
gas produced, but also improving its quality The gas passing from
the heated cylinder or retort of copper, or alloy of copper, is led to the
purifiers and condenser and treated in the ordinary manner.
When making gas from some descriptions of coal it may be desirable
to pass a stream of water gas through the retort in which the coal is
distilled and to lead the combined products through the heated cylinder
of copper or alloy as before explained.
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 29th January 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BOVERTON REDWOOD, of Fairlawn, North Finchley, in the County of
Middlesex, send greeting
WHEREAS Her most Excellent Majesty Queen Victona, by Her
Letters Patent, bearing date the Twenty-ninth day of July, in the year
of our Lord One thousand eight hundred and seventy-five, in the thurty-
ninth year of Her reign, did, for Пerself, Ier heirs and successois,
give and grant unto me, the said Thomas Boverton Redwood, Her
special license, that I, the said Thomas Boverton Redwood, my exe-
cutors, 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 Britam and Ireland, the Channel Islands, and Isle of Man,
an Invention for "IMPROVEMENTS IN THE MANUFACTURE OF GAS," upon the
condition (amongst others) that I, the said Thomas Boverton Redwood,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and scals, should particularly describe

page_text: 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 tho
Great Seal Patent Office within six calendar months next and imme-
diately 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 to improve the quality and increase
the quantity of gas obtained by distilling coal in retorts as now usual
For this purpose I cause the gas as it issues from a retort to come into
contact with heated copper or alloy of copper so arranged as to exposo
a large extent of surface to the gas. I prefer to pass the gas imme-
diately as it issues from the retort through a heated cylinder or retort
formed of or lined with copper or alloy of copper, and filled as described
in the Specification of a former Patent granted to me September 26th,
1874, No 3307, with scraps, turnings, wire, or wire gauze of the same
metal. By this means the hydrocarbon vapours which are carried off
with the gas as it issues from the retorts, and which according to the
mode of working hitherto adopted are condensed in the condensers, are
converted into a permanent gas rich in carbon, thereby not only
increasing the quantity of gas produced but also improving its quality
The cylinder or retort of copper or alloy of copper, which I call the
converting chamber or converter, should be as near as possible to the
retort in which the coal is distilled, and they should be connected by a
short pipe of at least four inches diameter to enable the gas to flow
freely into the converter without deposition of tar in the connecting
tube.
The converter should be heated externally by a fire, by which it can
be kept at a cherry red heat, and the gas after passing through the con-
verter should be conveyed to the condensers and purifiers through a pipe
of ample size, so that it may pass off freely without back pressure. The
scraps, turnings, wire, or wie gauze should not be packed so closely in
the converter as materially to obstruct the flow of the gas.
When the coal employed in the process yields a gas of very high
illuminating power, such as canuel coal, 1 cause a stream of what is

page_text: known as water gas, and which may be produced as described in the
Specification of my Patent of September 26th, 1874, No. 3307, to pass
through the retort in which the coal is distilled, and then lead the
combined products through the converter, arranged and heated as
already described.
Having thus described the nature of my Invention and the manner of
performing the same, I would have it understood that I claim as my
improvements in the manufacture of gas,-
First. Causing gas obtained by distilling coal and as it issues from the
retorts to come 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.
Second Causing a stream of water gas to pass through retorts in
which coal is being-distilled and leading the combined products as they
issue from the retort 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.
In witness whereof, I, the said Thomas Boverton Redwood, have
hereunto set my hand and seal, this Twenty-fifth day of January,
in the year of our Lord One thousand eight hundred and seventy-
SIX.