IMPROVEMENTS IN APPARATUS FOR PURIFYING COAL GAS
Year: 1885

page_text: I, ALEXANDER DEMPSTER, of Elland, in the County of York, Civil Engineer do
hereby declare the nature of the said invention for "IMPROVEMENTS IN APPARATUS
FOR PURIFYING COAL GAS" and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement, reference
being had to the accompanying sheet of Drawings and to the letters and Figures
marked thereon :—
The object of these improvements is to arrest the heavier impurities of coal gas,
such as the Tar, Ammonia, Carbonic Acid, and sulphuretted hydrogen at an early
stage in the manufacture of such gas, whereby the work thrown on the apparatus
is lighter than heretofore, better scope is afforded the various parts to perform their
respective functions without clogging, and an extreme pressure is not required to
secure proper and efficient working.
In the Drawings hereto annexed Figure 1 is a sectional elevation, and Figure 2 a
plan partly in section of an apparatus constructed with my improvements applied
thereto.
A is a cylindrical or other shaped vessel of cast iron or other suitable material,
placed by preference immediately after the condenser.. B is a pipe for the admission
of gas to the said vessel A. The said pipe B enters at the bottom of the vessel,
extends upwards therein and forms at its top a support for the cover plates thereof.
This pipe has four or more openings B' to distribute the entering stream of gas
equally to all parts of the inner chamber C. Around the inlet pipe B are placed
inclined perforated plates D fixed at such an angle that the gas issuing from the
openings B' impinges against the edges of the holes in the said inclined plates D,
and is thereby roughly broken up. A small stream of strong ammoniacal liquor
is passed over these inclined plates for the purpose of arresting some portion
of the sulphuretted hydrogen and carbonic acid, and also some of the heavier
hydro-carbons.
The openings B¹ in the inlet pipe B are made of such dimensions that the sum of
their areas shall be not less than four times the area of the inlet pipe in order to
allow the gas to come comparatively to a state, of rest so as to slowly deposit its
heavier compounds on the inclined perforated plates D. Surrounding these inclined
perforated plates are fixed a series of vertical perforated plates E attached at
heir upper edges to the top plate of the vessel A, and resting at their lower edges on
he stands or chairs R. These vertical plates are placed in concentric rings and are
ealed below in the strong ammoniacal liquor at the bottom of the vessel A, they
re perforated all over with holes varying in size in each plate say from one thirty-
econd of an inch to half an inch according to the nature of the gases under treat-
nent, the larger sized holes being made in the plate next to the inclined plates D,
nd the holes gradually diminish in size in each successive ring, so that the gas, in
s passage outwards through the holes in these plates, gets minutely divided and
roken up, whereby the heavier impurities are separated and deposited.

page_text: On the top of the vessel A is fixed a self-acting water or liquor distributor
composed of a tumbler or tipping tray H contained in the gas-tight chamber H'.
This tumbler H is filled from the supply pipe I and when filled tilts on its axis into
the position shown in dotted lines, and thus empties itself into pipe K from whence
the water or liquor descends through a self-acting syphon L into a box M with
radiating arms M¹ connecting it to one or more rings of spray tubing M² fixed
either at the side or between each of the vertical perforated plates E. These rings
of spray tube are pierced all round at regular distances, and at such angles as will
insure the water or liquor being equally distributed over the surfaces of the
perforated plates.
Any other suitable arrangement of water or liquor supply may be employed such
as a Turbine, Barker's Mill, or a rotary distributor.
An overflow syphon M³ is fixed near the bottom of the vessel A with a screen
plate N to take off the heavy tarry matters at the bottom of the vessel.
Cleaning-out holes G with suitable covers should be provided at the lower part
of the vessel A. to enable it to be freed from any accumulation that may be forined
from time to time, and similar cleaning holes Ŏ should be provided on the cover.
plate of such dimensions as will allow the vertical perforated plates to be cleaned
and inspected when necessary.
If preferred the gas may be introduced at the top of the vessel instead of at the
bottom or at any other point that may be found most suitable according to the
particular circumstances of each case. A single outlet F may be arranged at one
side only but preferably two outlets F F, one at each side, are employed as shown,
so as to divide the stream, the two outlets being united into one main P after
leaving the vessel A.
It is obvious that instead of the gas being admitted at the centre and taken off
at the sides it may be admitted at the sides and taken off at the centre, but in that
case the inclined perforated plates would be placed outside the vertical perforated
plates instead of inside as shown in the Drawings.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
First In coal gas purifying apparatus the employment of the inclined perforated
plates for the purpose of roughly breaking up and dividing the gas on its entrance
into the apparatus as herein before described, and illustrated in the Drawings hereto
annexed.
Second-In coal gas purifying apparatus the employment of concentric rings of
vertical perforated plates for the purpose of effecting the minute subdivision of the
gas as herein before described, and illustrated in the Drawings hereto annexed.
Third In coal gas purifying apparatus the employment of the tumbler or tilting
tray, the self-acting syphon, and the spray tubes for the purpose of supplying the
water or liquor to the apparatus and for the purpose of sealing the same, the whole
arranged, combined and operating as hereinbefore described, and illustrated in the
Drawings hereto annexed.
1000