IMPROVEMENTS IN THE PURIFICATION OF GAS."
Year: 1856

page_text: LETTERS PATENT to Frank Clarke Hills, of Deptford, in the County of
Kent, Manufacturing Chemist, for the Invention of "IMPROVEMENTS IN
THE PURIFICATION OF GAS."
PROVISIONAL SPECIFICATION left by the said Frank Clarke Hills at
the Office of the Commissioners of Patents, with his Petition, on the
27th May 1856.
. I, FRANK CLARKE, HILLS, of Deptford, in the County of Kent, Manu-
facturing Chemist, .do hereby declare the nature of the Invention for "IM-
PROVEMENTS IN THE PURIFICATION OF GAS," to be as follows:-
My Invention or improvements relate to purifying gas from ammonia, &c.,
by means of scrubbers filled with coke, or other divided media, over which
water or other purifying liquid is spread by any means, and allowed to per-
colate through, so as to wet the material, as is well understood, and my im-
provements are as follows:-First, for combining the use of steam with the use
of the said liquid,,by introducing it either into the bottom of the scrubber, or
into the pipes through which the gas passes, to the scrubbers, so as to mix
with the gas, and be,afterwards condensed by the materials in the scrubber,
and the water or other liquid percolating through and, over it.
Second, for using, warm water instead of cold, for spreading over the mate-
rials contained in the scrubber.

page_text: Third, for spreading the water or other liquid over the materials contained
in the scrubber, by means of porous diaphragms, or filter stones, or pipes,
which, by the filtration of the water, &c., present a dewy surface to the gas,
and cause the water, &c. to drop equally over the surface of the materials
contained in the scrubber.
Fourth, for spreading the water, &c. in a scrubber or other vessel in a
finely divided state, by means of a jet of steam mingling with it, and impinging
against a spreading surface, and thereby causing it to mingle with the gas,
and then passing the gas through a scrubber or condenser
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 27th November 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANK
CLARKE HILLS, of Deptford, in the County of Kent, Manufacturing Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of May, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Ier 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 "IыРROVEMENTS IN THE
PURIFICATION OF GAS," upon the condition (amongst others) that I, the said
Frank Clarke Hills, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particu-
larly 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 imme-
diately after the date of the said Letters Patent.
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 fol-
lowing statement thereof, that is to say :-
1

page_text: My Invention or improvements relate to purifying coal gas from ammonia,
sulphuretted hydrogen, and other impurities after it leaves the retorts (whether
it escapes into the retort house, or whether it is passed into the hydraulic
main or condensors), by means of scrubbers or purifiers, or vessels partially
filled with coke or charcoal, or sawdust, mixed or unmixed with hydrated or
precipitated oxides of iron or lime, and kept damp by water or other purifying
liquid, which is caused to spread over it and to percolate through it.
My improvements consist, firstly, in purifying the gas which escapes into the
retort house or other gas work buildings, which I effect in the following way:
I place a scrubber, made preferably of thin wrought iron, or other light mate-
rial, in the top of the roof, or in the upper part of the retort house, and, as far
as practicable, all the apertures in the slates or tiles and upper part of the
building are to be closed, so as to cause the gas in the building to escape
through the scrubber. To damp the gases, a steam pipe with holes or jets
pointing upwards should be placed in the bottom of the scrubber, and to cause
the gases to pass through the scrubber, the top of it sliould be covered air-
tight, either by dipping into a water lute, or otherwise, and a communication
by means of a pipe should be made to the chimney if there is share draught
enough in it to draw the gas through the scrubber. Or, instead of the
chimney, an exhauster may be used to draw the gas through the scrubber; or
a steam jet will answer the purpose, placed in a tube or chimney fixed in the
cover. The steam issuing upwards from the jet through the chimney or tube
will rarify the air and make it lighter, and so draw the gases out of the build-
ing through the media contained in the scrubber, and which media for this
purpose should consist of coke, charcoal, or sawdust, or such like material,
into which hydrated oxides of iron are absorbed, or with which they are mixed,
so as to form granulated or porous body sufficiently coarse to allow the
smoky gas in the building to pass through it. Lime may be used instead of
oxide of iron to mix with the charcoal, &c., but it is not so good. Peat or
sawdust charcoal is perhaps the best to absorb or mix with the hydrated
oxides of iron. The scrubber is to be furnished with gratings like a dry lime
purifier, and the purifying material is to be laid on them in thin layers, and
should be kept damp by an intermittent supply of water, which should be
caused to pass through it as in an ordinary scrubber, which will to a great
extent wash away the carbon of the smoke and dust which is deposited in the
charcoal, and will keep it permeable by the gas. This scrubber may be of
any convenient form, and there should be a bottom to it, turned up at the
sides to catch any water that may run through the purifying media in the
scrubber, and which water may be thence conveyed away. The sides of

page_text: the scrubber should not touch the bottom, but only come down as far as the
lowest grating, and between this grating and the bottom there should be left.
sufficient space for the gas to be drawn into the scrubber, and to pass up
through the media therein contained. Ten or twelve inches depth of opening
all round the sides will be in most cases be sufficient for purifying the
gas after it leaves the hydraulic main. The scrubber or purifier, through
which the gas is to pass, is to be filled with coke, broken stoneware,
or other such material, and which is to be kept damp by an intermittant
supply of cold water or other purifying liquid, as in the ordinary way.
This scrubber may be placed on the ground, and must have a closed bottom
instead of an open one, as before described, and steam is to be introduced into
the bottom of the scrubber below the bottom grating; or the stream may be
passed into the pipe through which the gas passes to the scrubbers, so as to
mix with the gas, and combine with the ammonia, and other condensable
impurities it contains. The mixed vapour and gas will then pass upwards.
through the coke or other divided media contained in the scrubber, and meet-
ing with the cold purifying liquid which is percolating down through it, the
vapour will be condensed with the ammonia, &c. which it has taken up, &
will fall to the bottom of the scrubber as ammoniacal liquor, and the gas will
be more pure.
My second improvement consists in using warm water instead of cold for
spreading over the materials contained in an ordinary scrubber. Cold water,
especially in winter, is apt to cool the gas too quickly, and thereby occasion a
deposition of napthalinė; and the tar, also, which is contained in the gas
becomes fixed, and occasionally stops up the interstices between the pieces of
coke or other material, or coats them over, so as to obstruct the free passage of
the gas through the scrubber; but when the water is warm, say, from 70 to
100° Fahrenheit, or thereabouts, the crystallization and deposit of the naptha-
line by sudden cooling is to a great extent avoided, and the tar is also greatly
.prevented from stopping the action of the scrubber. When steam is used in
conjunction with the purifying liquid, as already described, the cold liquid
which is spread over the top of the media in the scrubber will become warm,
by meeting the steam and gas which are passing up and coming in contact
with it; therefore, when steam is used in conjunction with water or other
purifying liquid, the liquid spread over the top of the scrubbing or purifying
materials should be cold.
My third improvement consists in spreading water or other clear liquid over
the materials contained in the scrubber by means of porous pipes, diaphragms,
or filter stones, which, by allowing the water to filter through them, will

page_text: present a dewy surface to the gas, and the water or other purifying liquid will
be caused to drop equally over the surface of the materials contained in the
scrubber; or a scrubber or condenser may be formed wholly of these porous
filtering plates or diaphragms instead of being filled with coke or other greatly
divided media, and the water being caused to filter, through these plates or
diaphragms, will present a damp surface to the gas, which will condense the
ammonia it contains. The porous diaphragms here referred to are principally:
the artificial filtering plates as made by Ransome and Sims, of Westminster.
Any convenient arrangement of the filter plates, which will allow the water to
pass through tpem and present an extended damp or dewy surface to the gas,
will answer the purpose. The top of an ordinary coke scrubber may be made
of an iron frame, in compartments, having these filter plates cemented into
them, so as to form a tank of a few inches deep to hold water for filtering
through and supplying the scrubber, as described. A gas-tight cover should
be fitted on the top of this water tank that no gas may escape.
My fourth improvement consists in spreading water in a finely divided state
in a vessel through which the gas which has escaped into the retort house
mingled with air and smoke is caused to pass before entering the scrubber
already described. This is effected by means of a steam jet, fixed in a small
funnel-shaped or concave basin, and which basin is placed in the centre of the
bottom part of the vessel, which may be of any convenient size or depth; and
the orifice of the steam jet is to be a few inches above the bottom of the basin
in the centre, and water is to be run at any required pace into the little
conical or funnel-shaped basin, and when it comes to the bottom of the basin
below the orifice of the steam jet, through which high-pressure steam is caused
to issue, it will be partially converted into vapour, and will be dispersed in all
directions, by which means the grosser or carbonacious impurities of the gases
passing through the vessel will be deposited or condensed before the gas passes
into the scrubber containing the purifying material, already described. This
vessel, in which the water is thus spread, should be made preferably of light
wrought iron, and may be conveniently placed below the scrubber in the roof,
before described, and may form an extension of it by making it so much deeper;
or, if preferred, it may be connected by pipes to the scrubber in any convenient
way.
Having thus described the nature of my Invention, and the mode of carrying
the same into effect, I proceed to state my claims in respect thereof, viz*:-
Firstly, I claim for purifying gas (whether escaping into the retort house or
into the hydraulic main) combining the use of steam with the use of purifying

page_text: liquids in scrubbers, or. purifiers containing the purifying and divided media, as
herein-before described.
Secondly, I claim the employment in the scrubbers of a warm instead of a
cold purifying liquid, as herein-before described.
Thirdly, I claim the distribution of the purifying liquid over the divided
media in the scrubbers or purifiers by means of filtering plates or diaphragms;
and I claim also the forming the scrubbers or purifiers of a series of such
filtering plates or diaphragms instead of coke or other divided media, as herein-
- before described.
Lastly, I claim spreading water by a jet of steam, as herein-before.
described.
In witness whereof, I, the said Frank Clarke Hills, have hereunto set my
hand and seal, this Twenty-seventh day of November, in the year of our
Lord One thousand eight hundred and fifty-six.
Witness,
JAMES MURDOCH.
F. C. HILLS. (L.S.)