IMPROVEMENTS IN THE TREATMENT OF APPARATUS EMPLOYED IN THE MANUFACTURE AND MATERIALS USED IN THE PURIFICATION OF GAS
Year: 1867

page_text: LETTERS PATENT to John Somerville, of the Gas Works, Maidstone,
and Robert Elsdon, Engineer, of Maidstone, in the County of Kent,
for the Invention of "IMPROVEMENTS IN THE TREATMENT OF APPARATUS
EMPLOYED IN THE MANUFACTURE AND MATERIALS USED IN THE PURIFICATION
OF GAS."
Sealed the 8th October 1867, and dated the 3rd July 1867.
PROVISIONAL SPECIFICATION left by the said John Somerville and
Robert Elsdon at the Office of the Commissioners of Patents, with
their Petition, on the 3rd July 1867.
We, JOHN SOMERVILLE, of the Gas Works, Maidstone, and ROBERT ELSDON,
Engineer, of Maidstone, in the County of Kent, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE TREATMENT OF APPARATUS
EMPLOYED IN THE MANUFACTURE AND MATERIALS USED IN THE PURIFICATION OF
GAS," to be as follows:-
The object of this Invention is to remove with rapidity the deposit of
carbon which accumulates in and adheres to the retorts or ovens used in the
distillation of coals or other materials for the manufacture of gas, and which
operation is commonly called scurfing.

page_text: The improvements consist in scurfing by the following means:-A cast
iron or other suitable pipe is introduced within the retort of sufficient length
to reach a few inches from the back. The retort, which is heated in the
ordinary manner, is then charged with a quantity of chalk or limestone. A
special retort lid or cover is provided, having a hole through which the pipe
before spoken of is drawn, leaving a few inches projecting on the exterior.
The lid is luted and secured to the mouth piece in the usual way. The cap
of the ascension pipe is then removed, and a current of air established through
the pipe and amongst the chalk or limestone in the retort; by this means
the chalk or limestone in the course of a few hours will be converted into
quicklime, and during the process the carbon adhering to the retort will be
removed and carried off through the ascension pipe. Thus not only is the
retort freed from a deposit which is as prejudicial to the economical manu-
facture as it is annoying to the gas maker, but an excellent lime is produced
without injury to the retort, and which may be used for the purification of
gas or other purposes. The process is also of the greatest advantage in works
where the gas is purified by lime, as it enables the manufacturer by charging
the retort with the spent or foul gas lime from the purifiers to revivify it, and
thus admit of the repeated use of the same material while it affords means for
the utilization of what is now a very offensive residual. In some cases it may
be found necessary to make a temporary connection between the top of the
ascension pipe and the chimney shaft, or other suitable outlet, so as to convey
away more completely any objectionable effluvia that might arise in the course
of the operation.
We lay no claim to the apparatus employed, that is, the pipe and perforated
lid, or in the case of long retorts the leaving of one end open while the other
remains closed, as they are old; but what we consider to be our Invention is,
the introduction of chalk, limestone, or foul gas lime for the purpose of
removing carbon without injuring the retort, while by the same operation a
useful product is obtained.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Somerville and Robert Elsdon in the Great Seal
Patent Office on the 2nd January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JOHN
SOMERVILLE, of the Gas Works, Maidstone, and ROBERT ELSDON, Engineer, of
Maidstone, in the County of Kent, send greeting.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of July, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirty-first year of ller reign,
did, for Herself, Her heirs and successors, give and grant unto us, the said
John Somerville and Robert Elsdon, Her special licence that we, the said
John Somerville and Robert Elsdon, our executors, administrators, and
assigns, or such others as we, the said John Somerville and Robert Elsdon,
our 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 TREATMENT
OF APPARATUS EMPLOYED IN THE MANUFACTURE AND MATERIALS USED IN THE
PURIFICATION OF GAS," upon the condition (amongst others) that we, the said
John Somerville and Robert Elsdon, our executors or administrators, by an
instrument in writing under our, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inveution,
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 we, the said John Somerville and Robert Elsdon,
do hereby declare the nature of our said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This Invention relates to the treatment of the retorts employed and the
materials used in the production of illuminating or heating gas, the object
being to remove as quickly as possible, without detrinient to the retorts
employed, the deposit of carbon which accumulates and adheres to the interior
surface of them, or the ovens used in the distillation of coals, or other materials
for the manufacture of gas, and which operation is commonly called
"scurfing."
The improvements consist in scurfing by the following means:- A pipe of
cast iron or fire-clay, or one constructed partly of cast iron and partly of fire-
clay, or of any suitable material or combination of materials, is inserted in
the retort so as to lie along the bottom thereof, and is of sufficient length to
reach from the front to within a few inches of the back. The retort, which
is heated in the ordinary manner, is then charged with chalk, limestone, or
"foul gas lime." A special retort lid or cover is provided having a hole,
through which the pipe before spoken of is passed leaving a few inches pro-

page_text: jecting on the exterior. The pipe is furnished near its outer extremity with
an ordinary throttle or other suitable valve for the purpose of regulating the
quantity of air to be admitted to the retort. The lid is luted and secured to
the mouth piece of the retort in the usual way. The junction between the
pipe and the cover should also be luted in a similar manner. The cap of the
ascension pipe is then removed and a current of air established through the
pipe and amongst the chalk, limestone, or foul gas lime in the retort; by
this means the chalk, limestone, or foul gas lime will be converted in the
course of a few hours into quicklime, and during the process the carbon
adhering to the retort will be carried off through the ascension pipe. Where
double or through retorts are used the cast iron or other suitable pipe before
mentioned may be dispensed with, the mouth piece at the end of the retort
opposite to that from which the cap of the ascension pipe has been removed
The
being left open or only partially closed by an ordinary lid or cover.
retort itself will then serve in lieu of the pipe to establish the requisite current.
of air through and amongst the chalk, limestone, or foul gas lime, with which
the retort is charged. In some cases it may be found necessary to make a
temporary connection between the top of the ascension pipe and some suitable.
outlet so as to convey away more completely any objectionable effluvia that
may arise in the course of the operation. By this process not only is the retort
freed from a deposit which is as prejudicial to the economical manufacture as
it is annoying to the gas maker, but an excellent lime is produced without
injury to the retort, and which may be used for the purification of gas or other
purposes. It is also of the greatest advantage in works where the gas is
purified by lime, as it enables the manufacturer, by charging the retort with
the spent or foul gas lime from the purifiers, to revivify it, and thus admit of
the repeated use of the same material, while it affords means for the utilization
of what is ordinarily a very offensive residual.
Having now described and particularly set forth the nature of this Invention,
and the manner in which the same is or may be carried into effect, we would
observe that we lay no claim to the apparatus employed, that is to say, the
pipe and perforated lid, or in the case of double or through retorts the leaving
of one end of the retort open while the other remains closed, as they are old;
we, however, do not confine ourselves to the precise details described or
referred to as variations may be made without departing from the general
means by which these improvements are produced; but what we consider to
be novel and original, and therefore claim as the Invention secured to us by the
herein-before in part recited Letters Patent is, the use of chalk, limestone, or
foul gas lime for the purpose of removing carbon without injury to the retort,

page_text: and the obtainment of a useful product thereby, in the manner substantially
as herein described.
In witness whereof, we, the said John Somerville and Robert Elsdon,
have hereunto set our hands and seals, this First day of January,
in the year of our Lord One thousand eight hundred and sixty-
eight.
JOHN SOMERVILLE. (L.S.)
ROBERT ELSDON. (LS.)
JOHN SOMERVILLE. (L.S.)
ROBERT ELSDON. (L.8.)