IMPROVEMENTS IN PURIFYING GAS
Year: 1852

page_text: LETTERS PATENT to Frank Clarke Hills, of Deptford, in the
County of Kent, Manufacturing Chemist, for the Invention of
"IMPROVEMENTS IN PURIFYING GAS."
PROVISIONAL SPECIFICATION left by the said Frank Clarke
Hills at the Office of the Commissioners of Patents, with his
Petition, on the 22nd December 1852.
I, FRANK CLARKE HILLS, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PURIFYING GAS" to be as follows:-
These improvements consist in using lime, or limestone, or mag-
nesian lime, slacked with liquid acids, or with solutions, or liquid
mixtures of the muriates, the sulphates, the phosphates, the nitrates,
and the acetates of the alkalies earths, the metals, and the alkalies.
The acids, or solutions, or mixtures, are to be added to the unslacked
lime in such quantities and of such strength as to slack it and
bring it to a powder, through which the gas is to pass to be purified.
Instead of slacking the lime with the materials above mentioned, the

page_text: SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said Frank Clarke Hills in the Great Seal
Patent Office on the 22nd June 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
FRANK CLARKE HILLS, of Deptford, in the County of Kent, Manufac-
turing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by
Her Letters Patent, bearing date the Twenty-second day of Decem-
ber, in the year of our Lord One thousand eight hundred and fifty-
two, in the sixteenth year of Her reign, did, for Herself, Her heirs
and successors, give and grant unto me, the said Frank Clarke Hills,
Her special licence that I, the said Frank Clarke Hills, my executors,
administrators, and assigns, or such others as I, the said Frank
Clarke Hills, 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 PURIFYING GAS," upon the condition
(amongst others) that I, the said Frank Clarke Hills, by an instru-
ment in writing under my hand and seal, should particularly de-
scribe 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.

page_text: NOW KNOW YE, that I, the said Frank Clarke Hills, 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):
My improvements in purifying gas consist in the employment for
that purpose of certain purifying materials, mixed or combined
with lime or limestone, or magnesian lime, or with spent lime from
gas works, for the purpose of dividing their particles so as to cause
them to present a greater surface to the gas. I carry out my Inven-
tion by any of the following methods:―
First, instead of slacking the lime which is ordinarily used for
purifying gas with water, I slack it with sulphuric or muriatic acids,
in such quantities and of such strengths as to bring the lime to a
powder, which is better to be rather damp. It will be best gene-
rally to have a considerable quantity of free lime to take up carbonic
acid and sulphuretted hydrogen. The acid employed is for taking
up the ammonia. The mixture may be used in the ordinary dry
lime purifiers, and when no longer fit for purifying gas, will be a
valuable manure.
Second, instead of using acid to slack the lime, the lime may be
slacked with solutions of the sulphate or persulphate, or bisulphate,
or the muriates of iron, or the sulphates or muriates of manganese,
or lime, or sulphate of alumine, so as to make a powder such as the
gas will easily pass through; or the lime may be partially slacked
with water, and the said solution (preferably in a concentrated state)
may be added to the lime to make a powder as described; or the
lime may be fully slacked with water, and the said sulphates or
muriates of iron or manganese, or lime in a crystaline or solid form
(and preferably ground or otherwise comminuted), may be mixed
with the lime.
Instead of using the lime mixed with the said sulphates or mu-
riates, it may be slacked in the usual way with water, and be used
mixed with oxides of iron in a state of minute division, so as to form
a mixture through which the gas can easily pass. The ammonia

page_text: contained in the gas may in this case be taken up in any way that
may be preferred.
In all these cases the lime acts as a separator, to divide or absorb
the said purifying materials so as to present a large surface to the
gas.
The said solutions or salts when mixed with lime as above de-
scribed, do not take up much ammonia from the gas, until the free
lime mixed with them becomes a carbonate or sulphuret. It is
therefore best to employ a succession of purifyers, so that the last
one through which the gas passes may be taking up the carbonic acid
and sulphuretted hydrogen, whilst the first, in which the lime has
become inert, is taking up the ammonia from the gas by means of
the said solutions or salts.
Third, the said solutions or salts, instead of being mixed with fresh
lime as above described, may be mixed with the ordinary spent
lime, from dry lime purifyers, as such lime usually still contains a
considerable portion of free lime, which by being thus mixed, becomes
useful.
Having thus described my Invention, and the manner of carry-
ing the same into effect, I claim for the purpose of purifying
gas, ―
First, using lime or magnesian lime, slacked with sulphuric or
muriatic acids, to bring the lime to a powder.
Second, using lime slacked with solutions or mixtures of either
of the sulphates, or persulphates, or bisulphates, or muriates of iron,
or sulphates or muriates of manganese or lime, or the sulphate of
alumine.
Third, using lime slacked or partially slacked with water, and
mixed with any of the said sulphates or muriates, or any combination
of them, in a crystaline or solid form, for the purpose of separating
their particles, and exposing their surfaces to the gas.
Fourth, I claim using slacked lime, mixed with such oxides of
iron as are effective for purifying gas, the lime being chiefly for the
purpose of dividing and exposing the said oxides to the gas.

page_text: Fifth, using spent lime mixed with the aforesaid salts or their
solutions, for the purification of gas, as herein-before described.
In witness whereof, I, the said Frank Clarke Hills, have
hereunto set my hand and seal, this 22nd day of June, in
the year of our Lord One thousand eight hundred and fifty-
three.
Witness,
JAMES MURDOCH.
F. C. HILLS. (L.S.)