IMPROVEMENTS IN APPARATUS FOR WASHING OR PURIFYING COAL GAS AND FOR PRODUCING AMMONIACAL WATER THEREFROM
Year: 1865

page_text: LETTERS PATENT to William Davey, of the Imperial Tar Works, White
Post Lane, Hackney Wick, in the County of Middlesex, for the Invention
of "IMPROVEMENTS IN APPARATUS FOR WASHING OR PURIFYING COAL GAS
AND FOR PRODUCING AMMONIACAL WATER THEREFROM."
Sealed the 24th October 1865, and dated the 19th May 1865.
PROVISIONAL SPECIFICATION left by the said William Davey at the
Ollice of the Commissioners of Patents, with his Petition, on the 19th
May 1865.
1. WILLIAM DAVEY, of the Imperial Tar Works, White Post Lane,
Hackney Wick. in the County of Middlesex. do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN APPARATUS FOR WASHING OR
PURIFYING COAL GAS, AND FOR PRODUCING AMMONIACAL WATER THEREFROM," to be
as follows:-
My Invention has reference to apparatus for washing the gas after passing
from the condenser, and has the double object of freeing the gas from
ammonia and of producing rich ammoniacal water.. For this purpose I
arrange a series of two or more vessels, each consisting of a closed receptacle
partly filled with water, maintained at a constant level and caused to flow
continually through the series of vessels in a manner to be hereafter described.
In the centre of each receptacle an enclosed space or chamber extends from
Price 8d.1
of the said Invention for "IMPROVEMENTS IN APPARATUS FOR
PURIFYING COAL GAS, AND FOR PRODUCING AMMONIACAL WATER THEREFROM," to be
as follows:-
My Invention has reference to apparatus for washing the gas after passing
from the condenser, and has the double object of freeing the gas from
ammonia and of producing rich ammoniacal water. For this purpose I
arrange a series of two or more vessels, each consisting of a closed receptacle
partly filled with water, maintained at a constant level and caused to flow
continually through the series of vessels in a manner to be hereafter described.
In the centre of each receptacle an enclosed space or chamber extends from
Price 8d.1

page_text: the top of the receptacle down to just below the level of the water, where it is
open, and a diaphragm, consisting either of very finely perforated plates, wire
gauze, or gridiron grating. extends from the immersed edge of the chamber
to the surrounding sides of the receptacle, such diaphragm being also situated
only a small depth below the level of the water. The gas passes through an
inlet pipe into the central chamber, and the area of the latter at its open lower
extremity is made to exceed that of the inlet pipe to such an extent that the
lower edge of the chamber being only slightly immersed, the gas can depress
the water in the chamber so as to escape from the same and pass underneath
the diaphragm all round the chamber with but a very slight degree of pressure.
From beneath the diaphragm the gas rises through the fine perforations,
meshes, or openings of the same, whereby it becomes divided into very small
globules, which, in bubbling up at a very slight pressure through the shallow
layer of water above the surface of the diaphragm, are thereby effectually
made to impart their ammonia to the water before passing into the space
above, whence the gas is conducted through an outlet pipe into the next
receptacle, where the above operation is repeated. By preference 1 place
upon the before-mentioned diaphragm in each receptacle a layer of pebbles or
other suitable granular material, whereby the action of the water upon the
gas bubbling through will be increased. The gas being made to pass into the
one end receptacle of the series the fresh water or weak ammoniacal water is
caused to pass into the other end receptacle, and is consequently made to flow
through the series in the reverse direction to that in which the gas is passing;
so that whilst the gas in passing from one receptacle to another becomes
more and more freed from ammonia, the water gradually accumulates more
and more ammonia until it flows off as very rich aumuoniacal liquor from the
receptacle into which the gas is first introduced. Instead of causing the gas
to escape below the bottom edge of the before-mentioned central chamber and
to pass up through a diaphragm as described, the central chamber may be
made to dip somewhat deeper into the water, and perforations or slits may
be formed in the immersed sides of the same, just below the level of the water,
through which perforations or slits the gas would escape, so as to rise up
through the water outside in the form of bubbles or globules. The depth to
which the water inside the chamber is depressed, and consequently the amount
of perforated surface through which the gas can escape will increase or
decrease in proportion as the quantity of gas passing into the apparatus
increases or decreases.
In the above described arrangement of a series of two or more vessels such
connections may be established between each of the vessels and the gas main

page_text: as will allow of each vessel being used separately if desired. As the first
receptacle of the series into which the gas is introduced will always contain
the strongest ammoniacal liquor, the further advantage may be gained of
purifying the gas, either wholly or partially, whilst passing through such
liquor, of the impurity known as bisulphide of carbon.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Davey, in the Great Seal Patent Office on the 18th
November 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I. WILLIAM
DAVEY, of the Imperial Tar Works, White Post Lane, Hackney Wick, in
the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of May. in the year of our Lord One
thousand eight hundred and sixty-five. in the twenty-eighth year of Her
reign, did. for Herself. Her heirs and successors, give and grant unto me, the
said William Davey, Her special licence that I, the said William Davey.
my executors, administrators, and assigns, or such others as I. the said
William Davey. 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
APPARATUS FOR WASHING OR PURIFYING COAL GAE, AND FOR PRODUCING AMMONIACAL
WATER THEREPROM," upon the condition (amongst others) that I the said
William Davey, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly 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 immediately after the
date of the said Letters Patent.
IN
NOW KNOW YE, that I, the said William Davey, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following.
statement thereof, reference being had to the accompanying Drawing and
to the figures and letters marked thereon, that is to say:-
My Invention has reference to apparatus for washing the gas after passing

page_text: from the condenser, and has the double objeci of freeing the gas from
ammonia and bisulphide of carbon, and of producing rich ammoniacal water.
For this purpose I arrange a series of iwo or more vessels, each consisting of
a closed receptacle partly filled with water or ammoniacal liquor, maintained
at a constant level, and caused to flow continually through the series of vessels
in a manner io he hereafter described. In the centre of each receptacle an
enclosed space or chamber extends from the top of the receptacle down to
just below the level of the water, where it is open, and a diaphragm consisting
either of very finely perforated plates, wire gauze, or gridiron grating, exiends
from the immersed edge of the chamber to the surrounding sides of the
receptacle. such diaphragm being also situated only a small depth below the
level of the water. The gas passes through an inlet pipe into the central
chamber, and the area of the latter at its open lower extremity is made to
exceed that of the inlet pipe to such an extent that the lower edge of the
chamber being only slightly immersed, the gas can depress the water in the
chamber so as to escape from the same and pass underneath the diaphragm
all round the chamber with but a very slight degree of pressure. From
beneath the diaphragm the gas rises through the fine perforations, meshes, or
openings of the same, whereby it becomes divided into very small globules,
which, in bubbling up at a very slight pressure through the shallow layer of
water above the surface of the diaphragm, are thereby effectually made to
impart their ammonia to the water or liquor before passing into the space
above, whence the gas is conducted through an outlet pipe into the next
receptacle, where the above operation is repeated. By preference. I place
upon the before-mentioned diaphragm in each receptacle a layer of pebbles or
other suitable granular material, whereby the action of the water upon the
gas bubbling through will be increased. The gas being made to pass into
the one end receptacle of the series the fresh water or weak ammoniacal
water is caused to pass into the other end receptacle, and is consequently
made to flow through the series in the reverse direction to that in which the
gas is passing, so that whilst the gas in passing from one receptacle to
another becomes more and more freed from ammonia the water gradually
accumulates more and more ammonia, until it flows off as very rich ammo-
niacal liquor from the receptacle into which the gas is first introduced.
Instead of causing the gas to escape below the bottom edge of the before-
mentioned central chamber and to pass up through a diaphragm as described,
the central chamber may be made to dip somewhat deeper into the water,
and perforations or slits may be formed in the immersed sides of the same,
just below the level of the water, through which perforations or slits the gas

page_text: would escape so as to rise up through the water outside in the form of bubbles
or globules. The depth in which the water inside the chamber is depressed.
and consequently the amount of perforated surface through which the gas can
escape, will increase or decrease in proportion as the quantity of gas passing
into the apparatus increases or decreases.
In the above described arrangement of a series of two or more vessels, such
connections may be established between each of the vessels and the gas main
as will allow of each vessel being used separately if desired. As the first
receptacle of the series into which the gas is introduced will always contain
the strongest ammoniacal liquor, the further advantage may be gained of
purifying the gas either wholly or partially whilst passing through such liquor.
of the impurity known as bisulphide of carbon and for this purpose also. gas
iar, liquid hydrocarbons, and other fluids capable of absorbing the bisulphide
of carbon may be employed, in addition to or in lieu of the ammoniacal liquor
in one or more of the before-described vessels.
On the accompanying Drawing is shown the construction of my improved
apparatus. Figure 1 shows a part sectional elevation: and Figure 2 shows a
plan of two such apparatus, capable of acting either separately or in combina-
tion; and Figure 3 shows a plan of one of the vessels with the cover removed.
Similar letters of reference indicate similar parts in each of the Figures.
A, A. are closed vessels of iron or other suitable metal. having a central
chamber B fixed to the cover and passing about half way down, which
chamber is open at bottom, as shown, and is supported by columns C. A
grating, or perforated or gauze diaphragm D. passes from the lower edge of
the chamber B to the circumference of the vessel A. and a layer of pebbles or
other suitable granular material E is placed upon the grating. The central
chambers communicate with the gas main F through branches G. G¹. provided
with valves, and the spaces surrounding such chambers communicate with the
gas main through branches H. II. valves I. 1. being provided in the gas main
between the branches G, G', and H, H. The vessels A. A'. are kept filled
with water to a level slightly above the gratings D. from a supply pipe J.
through funnel-mouthed pipes K, K', which are sealed at bottom by dipping
into the water in the vessel. The water either flows off separately from cach
vessel through pipes L, L', which are sealed by dipping into receptacles for
the water M, M', whence the water is conducted to wherever required through
pipes N, N¹, and O; or, instead of being conducted away separately from
each vessel the water is made to flow from the vessel A¹ into A, through a
pipe P. In this case, however, it is preferred to raise the vessel A', to a
slight extent above the level of the vessel A, so as to make the water level in

page_text: the vessel A stand rather higher than in A', as otherwise the pressure of the
gas in first entering the vessel A would depress the level of the water therein
below the grating D, and raise it proportionately higher in the vessel A¹,
whereby the gas would pass through the vessel A without being acted upon. By
raising the vessel A as described, this effect of the lowering of the water level
in A by the pressure of the gas will be counteracted, by the grating D of the
vessel A being itself lower than in A'. The gas main F is provided with a
"by-pass provided with a valve at R. the pipe F being also provided with
valves at S. S'; so that if the vessels A. A', require cleaning or repairs, then
by closing the valves S. S'. and opening the valve at R. the gas is conducted
past the vessels A. A'. without entering them.
The action of the before described apparatus is as follows:-If both the
vessels A, A', are required to act in conjunction, then by opening the valves
at H. H', and ai G, G', and closing the valves at I, 1. the gas is made to
flow from the pipe F into the chamber B of the vessel A. By the pressure
which the gas exerts the water level inside the chamber is depressed (and
consequently its level is raised outside the chamber) until the gas can escape
beneath the lower edge of the same, so as to pass beneath the grating D,
whence it passes up in the form of small bubbles through the stratum of water
and pebbles above the grating. By this means the gas is brought into intimate
contact with the water, which consequently takes up the ammoniacal vapour
contained in the same; and if in place of water strong ammoniacal liquor or
gas tar, liquid hydrocarbons, or other fluids capable of absorbing bisulphide
of carbon be employed, this impurity may also be removed from the gas.
The gas after passing into the space surrounding the chamber B escapes
through the pipe H into the pipe F, whence it passes through the branch G
into the central chamber of the vessel A', where the same operation as above
described is repeated, and whence the gas escapes through the branch H
back into the gas main F, which conducts it to the other purifying apparatus.
At the same time, if a communication between the vessels is established by
the pipe P as described, and the cock j in the pipe J is closed whilst the
cock is opened, the water flows into the vessel A' through the pipe K, and
after having taken up a certain proportion of ammonia from the gas passing
through in the opposite direction, flows through the pipe P into the vessel A,
where it absorbs a further quantity of ammonia from the gas that is freshly
entering from the condenser, and after having attained the required degree of
saturation it is allowed to flow off through the pipe L. By this arrangement
it will be seen, that the gas as it becomes more and more freed from ammo-
niacal vapour is brought in contact with water that has taken up least of

page_text: such ammoniacal vapour, whereby the separation of such vapour is effected in
the most perfect manner. This may however also be effected even if the
the water does not pass from the vessel A¹ into A. but flows into and off from
each vessel separately, by allowing the water in the vessel A to remain in it
until it has attained a certain degree of saturation, whilst the water in the
vessel A is allowed to flow off when it has absorbed a considerably less
quantity of ammonia than that in the vessel A. By closing the connection
between the vessels by means of the pipe P also the gas may be treated with
water in the vessel A' for the purpose of freeing it from ammonia as described,
whilst instead of water, gas tar, or other fluid before mentioned may be
introduced into the vessel A through the pipe K in order to free the gas from
bisulphide of carbon while passing through such vessel.
By the before described arrangement of valves in the pipe F it will be seen
that by closing the valves at H and G, and by opening the valve at I, the gas
may be made to pass by the vessel A, in case this requires cleaning or repairs,
and may be acted upon in the vessel A' only; or again, by closing the valves
at 1 and G', and opening 1', the gas may in the same way be made to pass
by the vessel A'. The pipe O communicates with the bottom of each vessel
by means of a branch 0, 0, provided with a cock as shown, through which
the fluid may be entirely drawn off when required. Although only two
vessels A, A' are shown in combination in the Drawing, it will be evident
that any other number may be employed to form the series, according to the
degree to which it is required to free the gas from ammonia or bisulphide of
carbon.
Figure 4 shows a sectional elevation of a slightly modified arrangement
of the before described apparatus. In this case in place of the grating or
perforated diaphragm extending from the central chamber B to the sides of
the vessel A, the lower part D of the central chamber B is made to extend
some distance below the level of the fluid, and is there considerably widened
out and provided with perforations as shown, so that the gas in depressing
the fluid within the chamber uncovers a portion of the perforations in such
lower part, through which perforations the gas then passes in small bubbles
and rises through the fluid into the space surrounding the chamber B. It
will be seen by this arrangement that the depth to which the water is
depressed in the chamber, and consequently the amount of perforated surface
uncovered, will vary in direct proportion with the increase or decrease of the
quantity of gas passing through, so that the apparatus will act equally efficient
in all cases.
Having now described the nature of my Invention, and in what manner

page_text: the same is to be performed, I wish it to be understood that I do not claim
generally the employment of apparatus for purifying coal gas. in which
such gas is caused to pass through water, tar, and other fluids for the
purpose of taking up the ammonia and bisulphide of carbon from the gas,
as I am well aware that such apparatus has already been employed, but what
1 claim is,-
First, constructing apparatus for freeing coal gas from ammonia and
bisulphide of carbon, consisting of a closed vessel having a central chamber,
the lower open end of which dips slightly beneath the level of the water or other
fluid contained in the vessel, and from which immersed edge of the chamber a
grating, or perforated or gauze diaphragm, also slightly immersed beneath
the level of the fluid is made to extend to the sides of the vessel, so that the
gas being made to pass into the central chamber depresses the fluid so as to
pass under its lower edge and beneath the grating or diaphragm, whence
it rises through the openings or perforations thereof, and through the shallow
stratum of water over the grating into the space surrounding the central
chamber, substantially as and for the purposes herein-before described.
Second, placing upon the aforesaid grating or perforated or gauze diaphragm
a layer of pebbles or other suitable granular substance, in order the more
effectually to bring the bubbles of gas into intimate contact with the fluid.
Third. constructing the central chamber with its lower end immersed
some depth into the fluid, and widened out, and forming in such immersed
portion perforations or small openings in such manner that the gas in depressing
the fluid inside the chamber uncovers such perforations or openings, so as to
escape through them. substantially as herein-before described with reference
to Figure 4 on the accompanying Drawing.
Fourth, the employment of a series of two or more such before described
apparatus acting in combination with each other and with the system of pipes
and valves in manner herein-before described with reference to the accom-
panying Drawings,
In witness whereof, J, the said William Davey, have hereunto set
my hand and seal, this Eighteenth day of November, in the year of
our Lord One thousand eight hundred and sixty-five.
W. DAVEY. (L.S.)