IMPROVEMENTS IN THE MANUFACTURE OF GAS, AND IN APPARATUS TO BE USED IN TRANSMITTING GAS
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
ANGUS CROLL, of the Gas Works, Tottenham, in the County Middlesex,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-second day
of August, One thousand eight hundred and forty-eight, in the twelfth year
of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Alexander Angus Croll, my exors, admors, and assigns,
Her especial licence, full power, sole privilege and authority, that I, the
said Alexander Angus Croll, my exors, adñiors, and assigns, and such others
as I, the said Alexander Angus Croll, my exors, admors, or assigns, should
at any time agree with, and no others, from time to time and at all times
during the term of years therein expressed, should and lawfully might make,
use, exercise, and vend, within England, Wales, and the Town of Berwick-
upon-Tweed, my Invention of "IMPROVEMENTS IN THE MANUFACTURE OF GAS,
AND IN APPARATUS TO BE USED IN TRANSMITTING GAS;" in which said Letters
Patent is contained a proviso that I, the said Alexander Angus Croll,
should cause a particular description of the nature of my said Invention,
and in what manner the same is to be performed, by an instrument in
writing under my hand and seal, to be inrolled in Her said Majesty's High
Court of Chancery within six calendar months next and immediately after
the date of the said in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Alexander Angus Croll, do hereby declare that the nature of my said
Invention, and the manner in which the same is to be performed, are fully
described and ascertained in and by the following description thereof, that is
to say :-
My Invention consists,―
First, of improvements in setting retorts and apparatus for making gas
from coal.
Secondly, my Invention consists of a mode of employing steam passed
through highly heated carbon, and then mixing it with carburetted hydrogen,
as it is distilled from coal.
'
Thirdly, my Invention consists of so employing sulphurous acid gas as to
combine with sulphuretted hydrogen gas, as to cause the sulphur of the gasses
to be thrown down or precipitated.
:
Fourthly, my Invention consists of improvements in apparatus. to be used
in transmitting gas.
!
And, in order that my Invention may be most fully understood and readily
carried into practice, I will proceed to describe the means pursued by me.
It has heretofore been proposed to employ long retorts capable of being fed at
each end, and in such manner that the products of gas from the last charge d
shall pass over the charge which has been for a length of time in the retort;
for which purpose each such retort was provided with a rising pipe at each.
end to carry off the gas evolved, first from one end of the retort and then at
the other; the different ends of each retort being fed at distant intervals, so
that the two charges therein will at all times be in a different state of process,
one charge being comparatively fresh; whilst the other charge will be compa-
ratively spent. Now the first part of my Invention consists of using similar
retorts, that is, retorts which can be fed at each end; but, in place of having
two rising pipes, one at each end as heretofore, for carrying off the produced
gas, I have only one rising,pipe, which I apply at one end of a retort; and
then, in place of feeding the two ends alternately, and at distant periods one
from the other, I charge both ends at the same time, by which arrangement I
have found considerable advantage result in the manufacture of gas.
I will now describe the second part of my Invention, which has for its
object the use of steam passed through carbon at a bright red heat, and then
causing it to pass over or amongst the charge of coal which is being distilled.
in a retort. For this purpose I prefer to use retorts such as above described,-
and at the end most distant from the rising pipe I charge the retorts with
coke, and have a steam pipe to convey steam into the retort at that end, and

page_text: at the other. end of the retort I from time to time supply a charge of coal, say
at every five hours, and I allow steam to flow in for about the first three hours
of each charge; and I have found that about fifteen gallons of water eva-
porated and caused to pass into retorts for each ton of coals (that is, when
Newcastle coal is used, but when kennel coal is used the quantity should bo
increased) produces the most advantageous working; but I do not confine
myself to the use of that quantity, the object being to obtain a larger quantity
of gas of a fair illuminating power and a less produce of tar.
I will now describe the third part of my Invention, which has for its
object the use of sulphurous acid in such manner as to deprive carburetted
hydrogen gas of the sulphuretted hydrogen gas with which it is conta-
minated, and thus to obtain the sulphur of both compounds in the form
of flowers of sulphur. I first make a solution of sulphurous acid in water
by connecting a vessel or vessels of cast iron (arranged as a Woulfe's
apparatus used for impregnating liquids with gases) with an oven or other
suitable apparatus for carrying on the combustion of sulphur, and, by
nicans of an air-pump or other arrangement for producing a draft connected
with the vessel containing the water or liquid to be impregnated, I cause
a current of sulphurous acid gas from the burning sulphur to pass through
the water or liquid, and by which it is largely absorbed. This I do till
the liquid is nearly saturated with sulphurous acid; and to effect this
about six ounces of sulphur will require to be burned for every gallon of
water. The sulphurous acid thus made I transfer to the first of a series of
three vessels (or it may be other number of vessels) constructed and arranged
exactly in the same manner as the wet lime purifiers in common use, at gas
works. The other two vessels are charged with a weaker solution derived
after the process has been once put in operation from the washers to be
afterwards mentioned, and by a portion of the sulphurous acid which is
disengaged from the first vessel. I charge each of these vessels exactly.
as is done with the liquid in the wet lime purifiers, videlicet, so that
the gas may pass through and come into extensive contact with the solu-;
tion of sulphurous acid, and I cause the gas to pass first into the vessel
with the strong solution, and thence into the second, and thence again
into the third. In thus passing through these successive purifiers the
sulphuretted hydrogen in the coal gas and the sulphurous acid are both
decomposed, and sulphur is abundantly deposited. When the sulphurous acid
in the first vessel has been all decomposed, or nearly so, the contents must be
discharged into a suitable reservoir, where the liquor may settle or be filtered,
and the sulphur obtained and dried. The vessel must then be charged with a

page_text: new solution, and the process proceed as before. But I prefer in practice, instead
of using a separate vessel, as already described, for preparing the solution of
sulphurous acid, to use two sets of purifiers alternately, and therein to charge
the liquid with sulphurous acid in the one set, when the coal gas is being
passed through the other; and instead of using fresh water for this purpose, I
transfer the liquid already partially charged from the second to the first, and
the contents of the third I transfer to the second, as in like manner the third
has been charged from the washers now to be described:-I find that, owing
to the volatility of the sulphurous acid, a portion of it is carried over with tho
gas, and therefore to free it from this impurity I cause it to pass through other
threo vessels, which I call washers, and finally, that every trace of impurity
may be removed, I pass it through a common dry lime purifier. The freedom
from impurity may be ascertained at any stage of the process by the usual test
of acetate of lead for sulphuretted hydrogen, and by the smell if there be even
a most minute portion of sulphurous acid present. These washers are
arranged so as to be put in connection with either series of purifiers at
pleasure, and any construction may be adopted by which there is a free
passage for the gas, and a thorough exposure of it to the water, and for this
In
purpose the ordinary lime purifiers already referred to answer very well.
the washers these are charged with water only, and as it becomes impure it is
transferred through the series onward, and then into the purifiers, the last
vessel of the series being always supplied with the fresh water, and care being
taken that it never gets so charged with sulphurous acid as to allow of its
being disengaged with the gas. Such is the general mode of proceedure, but
in practice it is not necessary to discharge or transfer the contents of the
purifiers every time they are impregnated with sulphurous acid, but only when
the accumulation of sulphur, tar, &c., renders it necessary; and also, if moro
water be required in the washers than it is necessary to transfer to the purifiers,
then it may be run out, and after depositing its sulphur may go to waste.
I will now describe the fourth part of my Invention. It has heretofore
been proposed to have gas holders fixed at a distance from the works, in
order that they may be near or in the locality where the supply is to
be given, and it has been proposed to aid the transmission of gas from
the works by means of exhausting apparatus. Now, the fourth part of
my Invention consists of apparatus similarly arranged to that above men-
tioned, that is, a gas holder or gas holders at a distance from the works,
together with exhausting apparatus to take the gas from the main, and drive
it into the gas holder or gas holders near such exhausting apparatus;
and the peculiar character of this part of the Invention consists of so

page_text: working that the gas in the main between the gas works and the exhauster
in the vicinity of the gas holder at a distance may be maintained at a
proper degree of pressure for supplying the intermediate district. For this
purpose I cause the exhausting apparatus to be capable of taking the gas
to such an extent as to exhaust the gas main, so that, if no provision
were made for maintaining the gas at a proper degree of pressure in the
main, no supply of gas to the intermediate district could take place from
the main when the exhausting apparatus is at work. I cause there to be a
branch pipo from the main to the gas holder, such branch pipe being con-
nected at a point (from the gasholder) beyond the exhausting apparatus; and
on such branch pipe I apply a governor, which I prefer to be such as are now
used at gas works to regulate the pressure of gas in the mains. By this
arrangement, although the exhausting apparatus will at all times when at
work be propelling gas into the gas holder from the gas main with a tendency
to exhaust the main, a quantity of gas will pass from the gas holder by the
branch pipe into the main, which quantity will be regulated by the governor,
which will thus keep the gas in the gas main at the desired working pressure,
and the gas holder or gas holders at a distance from the works will only be
supplied by the exhausting apparatus with the quantity of gas which would
otherwise cause the gas in the main to rise in excess of the desired working
pressure.
Having thus described the nature of my Invention and the manner in
which the same is to be perforined, I would have it understood that I do not
confine myself to the details herein described, so long as the peculiar character
any part of my Invention be retained. But what I claim is,―
of
First, the mode of manufacturing gas herein described, whereby retorts
capable of being fed or charged at each end are employed, the gas being
conveyed off at only one end.
Secondly, I claim the mode of employing steam in the manufacture of gas,
as above described.
Thirdly, I claim the purifying coal gas by employing sulphurous acid gas,
so as to separate and thus obtain the sulphur in the form of flowers of
sulphur. And,
Fourthly, I claim the mode of arranging apparatus for transmitting gas, as
herein described.
In witness whereof, I, the said Alexander Angus Croll, have hereunto
set my hand and seal, this Twmy-second day of February, in the year
of our Lord One thousand sight hundred and forty-nine.
A. ANGUS (L.B.) CROLL.

page_text: AND BE IT REMEMBERED, that on the Twenty-second day of February,
in the year of our Lord 1849, the aforesaid Alexander Angus Croll came
before our said Lady the Queen in Her Chancery, and acknowledged tho
Specification aforesaid, and all and every thing therein contained and speci-
fied, in form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Enrolled the Twenty-second day of February, in the year of our Lord
thousand eight hundred and forty nine