IMPROVEMENTS IN APPARATUS USED IN GAS WORKS FOR CLEANSING AND PURIFYING GAS FROM AMMONIA AND OTHER IMPURITIES
Year: 1871

page_text: LETTERS PATENT to William Thomas Walker, of 7, Holly Terrace,
Highgate, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN APPARATUS USED IN GAS WORKS FOR CLEANSING AND
PURIFYING GAS FROM AMMONIA AND OTHER IMPURITIES.”
Sealed the 2nd February 1872, and dated the 3rd October 1871.
PROVISIONAL SPECIFICATION left by the said William Thomas Walker
at the Office of the Commissioners of Patents, with his Petition, on
the 3rd October 1871.
I, WILLIAM THOMAS WALKER, of 7, Holly Terrace, Highgate, in the
County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN Apparatus USED IN GAS WORKS FOR CLEANSING
AND PURIFYING. GAS FROM AMMONIA AND OTHER IMPURITIES," to be as
follows:-
These improvements have for their object the purification of coal gas
from ammonia and other impurities, for which purpose scrubbers have

page_text: been heretofore used in gas works, consisting of a circular vessel filled
with coke, supported upon gratings, through which water is showered
down in opposition to the gas passing up and meeting the descending
liquid and becoming washed. The water being supplied by revolving
syphon tubes on to a circular framed wheel, or tray, or grating charged t
with birch wood revolving horizontally, operated or driven by a steam
engine or other motive power.
The objects of my Invention are to improve the efficacy, working
action, and purifying power of scrubbers, and to greatly lessen and
reduce their cost. Hitherto the enormous expense of the necessary ]
adjuncts and appliances have practically rendered their use prohibitory
to gas companies.
The height heretofore of scrubbers has generally been about 20 to
25 feet.
By experiments that I have made I have discovered that by greatly 1
increasing their height, and making the bottom concave instead of flat,
I greatly improve their purifying power, I am enabled to greatly reduce
the quantity of water required, and to obtain a highly concentrated
ammoniacal solution towards the lower part of the scrubber, which I
find acts as a solvent for bisulphide of carbon, and other deleterious 2
impurities hitherto found impracticable to remove from coal gas.
One of the most prohibitory causes referred to above, heretofore
existing against the use of scrubbers described, has been the great
expense and difficulty attending the water supply to the required
height. This difficulty will be enormously increased by the still greater 2
increase in the height of the scrubbers described, the water service of
which will be 60 to 70 feet instead of 20 to 30 feet heretofore used.
Heretofore it has been customary to build a water tower or other
building at a great expense, sufficiently high to support a water tank
to feed the tops of the scrubbers.
My Invention will abolish the expense of these water towers or
other buildings. I convert the scrubbers themselves into water towers,
making them carry support and store their own water service tanks,
thus effecting a great saving in money, space, and convenience. I next
cover in the top of the scrubber with a light building, enclosing the a

page_text: water tank, pipes, & machinery, to protect all from frost. The air
inside the building will be made temperate by the warmth of the
scrubber itself, instead of being exposed to the weather on the top of an
isolated building as heretofore, or it can be heated by steam from a
boiler, or waste steam from an engine.
I also improve and cheapen the means of working and feeding the
revolving horizontal water spreading arms with water, by making a¨
horizontal water joint inside the driving wheel or rigger.
Where the height at my disposal is very contracted, I use one syphon
to seal the water supply of all the revolving water spreading arms,
which syphon I attach to the side of the scrubber, or any other
convenient position, and work the revolving water spreading arms in
water-tight stuffing boxes.
Instead of leather or gut bands heretofore used, I substitute gearing,
horizontal or vertical, and eccentric toothed wheels, driven by a steam
engine or other motive power from the centre shaft, for causing the
arms to travel at a slower speed over the larger surfaces, to spread the
water equally over every part.
1
SPECIFICATION in pursuance of the conditions of the Letters Patent,-
filed by the said William Thomas Walker in the Great Seal Patent
• Office on the 20th March 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
THOMAS WALKER, of 7, Holly Terrace, Highgate, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of October, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-.
fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Thomas Walker, Her special
licence that I, the said William Thomas Walker, my executors,
administrators, and assigns, or such others as I, the said William Thomas
Walker, my executors, administrators, and assigns, should at any time.

page_text: agree with, and no others, from time to time and at all times there-
after 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 APPAratus used IN GAS WORKS FOR CLEANSING 5
AND PURIFYING GAS FROM AMMONIA and other IMPURITIES," upon the condition
(amongst others) that I, the said William Thomas Walker, 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 1
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.
NOW KNOW YE, that I, the said William Thomas Walker, do hereby
declare the nature of my said Invention, and in what manner the same 1
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the Drawing
hereto annexed, and to the figures and letters marked thereon, that is
to say :-
These improvements have for their object the purification of coal gas 2
from ammonia and other impurities, for which purpose scrubbers liave
been heretofore used in gas works, consisting of a circular vessel filled
with coke, supported upon gratings through which water is showered
down in opposition to the gas passing up and meeting the descending
liquid, becomes washed, the water being supplied by revolving syphon 2
tubes on to a circular framed wheel charged with birch wood revolving
horizontally.
The objects of my Invention are to improve the efficacy, working
action, and purifying power of scrubbers, and greatly reduce their cost.
The height heretofore of scrubbers has generally been about twenty to 3
twenty-five feet. By experiments that I have made I have discovered
that by greatly increasing their height (say to sixty or seventy feet, the
bottom being made concave instead of flat,) I greatly improve their
purifying power, thereby I am enabled to greatly reduce the quantity of
water required, and to obtain a highly concentrated ammoniacal solution
towards the lower part of the scrubber, and which I find to act as a

page_text: -
solvent for bisulphide of carbon,' and other impurities which it has
hitherto been found impracticable to remove from coal gas.
Heretofore it has been customary to build a water tower or other
building at a great expense, sufficiently high to support a water tank
to feed the tops of the scrubbers.
By my Invention I obviate the expense of these water towers or other
buildings by converting the scrubbers themselves into water towers,
and making them so as to carry their own water service tanks, thus
effecting a great saving in money and space, and increasing their
convenience; and I cover in the top of the scrubber with a light
building, enclosing the water tank, pipes, and other machinery to
protect them from frost. The air inside the building will be rendered
temperate by the warmth of the scrubber itself, instead of being exposed
to the weather on the top of an isolated building as heretofore, or it can
be heated by steam from a boiler, or waste steam from an enginc.
I also improve and cheapen the means of working and feeding the
revolving horizontal water spreading arms by means of a water scal
box of novel construction.
Where the height at my disposal is very limited, I use one syphon to
seal the water supply of all the revolving water spreading arms, which
syphon I attach to the side of the scrubber, or place in any other
.convenient position, and work the revolving water spreading arms in
water-tight stuffing boxes.
I obviate the use of leather or gut bands heretofore used, and
substitute gearing, horizontal or vertical. I employ eccentric toothed
wheels for causing the arms to travel at a slower speed over the larger
surfaces to spread the water equally over every part.
Having thus described the nature of my Invention, I will now more
particularly describe the same, and the best means I am acquainted with
for carrying it into effect by reference to the accompanying Drawing, in
which Figure 1 is an elevation of the exterior of my improved apparatus
or scrubber standing upon its foundations, and shewn as being formed of
separate cast-iron plates. It can be made of separate cast-iron cylinders
placed one upon another, or of wrought-iron plates rivetted together.
It will be seen that the top of the scrubber is enlarged, and the whole

page_text: closed in by a small house, the framing of which is formed by wrought
T or other shaped iron uprights fixed to the sides of the enlarged top of
the scrubber, and carried up to the height of the bottom of the water
tank, where they are united by a wrought-iron curb ring, which by
means of transverse bars carries the water tank and forms a frame for
covering in the building. Figure 2 is a sectional elevation of the same,
the bottom being concave instead of flat, to enable the ammoniacal
liquor which is very strong, and in some cases very volatile, to be at
once discharged out of the scrubber, on reaching the bottom, into the
self-acting syphon on the left hand, and thence into air-tight tanks or
proper receptacles prepared for it.
In the scrubber there are six tiers of gratings or sieves formed of cast
iron, wrought iron, or wood, and upon these gratings coke by preference
is placed for giving a scrubbing or washing surface. The Drawing
shews six tiers or columns of coke, cach about eight feet deep, and 1
placed upon the six gratings; but a larger or smaller number may be
employed. The gratings are supported in the middle by the centre
column, which likewise forms the outlet of the purified gas, and they
are supported upon the sides of the scrubber by strong cast-iron lugs in
place of shelves; the object of this improvement being to let the
ammonical water or liquor flow down the sides of the scrubber without
the interruptions or impediments presented by projecting shelves. The
Drawing shews the inside of the enlarged part of the scrubber at the
top, with the machinery and water tank for feeding the scrubber
enclosed inside the house. The scrubber thus forms its own water:
tower, and supports the whole of its machinery and water supply tank,
and covers in the whole from the effects of the weather. By these
improvements I avoid the expense of a separate water tower to feed the
scrubber.
Figure 3 shews an enlarged view of the machinery inside the enlarged
top of the scrubber, at a point immediately below that at which the
tubes from the water tank discharge into the funnels or receivers H, H,
of which there are three shewn in plan. Figure 4.

page_text: lying upon it, and the other half shews the construction of the frame.
Figure 6 is an enlarged view of my improved construction of water
receiver, with its funnel H on the top and supported by the standard
shewn.
The junction of the vertical supply tube is shewn at Figure 7,-
where it forms an oil cup also. An eccentric wheel is fixed on the
vertical tube, and what I term a water seal box beneath it. The
tube descends from this box into the interior of the scrubber with its
revolving arm inside.
Figure 8 shews an enlarged section of my improved water seal box.
Figure 9 is a plan of my improved construction and arrangement
of eccentric wheels.
Referring again to Figure 2, the scrubber therein shewn is supposed
to be about sixty feet high in its working parts, and having six
columns of coke as before described. Foul gas highly charged with
ammonia is admitted at the bottom by the inner pipe, passes upwards
and circulates through the whole of the coke in the direction shewn by
the arrows, which coke is kept wetted and soaked by minute streams of
clean water, successively renewed and kept falling in showers by the
machinery at the top of the scrubber. By the time the foul gas reaches
the top of the scrubber and is ready to pass down the outlet pipe, as
shewn by the arrows, it will have become purified from ammonia, the
whole of which will have been taken up and discharged out of the
bottom of the scrubber.
Proceeding to further describe the improved water spreading
machinery, and referring to Figure 3, motive power is transmitted to
the horizontal shaft A, which is supported upon vertical standards, and
which has a toothed wheel at its extremity gearing into a horizontal
toothed wheel on the vertical shaft B, causing it to revolve slowly,
videlicit, about two or three revolutions per minute, and carrying with it
the circular wrought-iron frame G, shewn in plan Figure 5.
The horizontal frame G, revolving as herein-before described, is filled
with brushwood, which is laid in regular layers upon it, and. then

page_text: securely bound and attached to the circular frame, which, by the
enlargement of the top hercin-before described, overlaps the bore or
inside diameter of the scrubber. Upon the vertical shaft B a horizontal
toothed wheel D is fixed, and as the vertical shaft B revolves, as before
described, motion is given by the wheel D to three other wheels E, E, E, |
which gear into it. These three wheels give motion to three horizontal
shafts, having wheels at their outer ends, each of which gears into
another wheel on the vertical spindles F, upon cach of which is fixed a
horizontal eccentric wheel, gearing into another eccentric wheel fixed
upon the water tube. These wheels are shewn in enlarged view:
Figure 9. The water tubes, of which there are three shewn, pass
through stuffing boxes into the interior of the scrubber.
The mode of action of the improved water spreading machinery is as
follows:-
The cocks of the three outlet tubes from the water tank, Figure 2, are:
opened and the water is admitted into the three funnels of the vertical
tubes, down which it passes into the water scal box, shewn in detail
Figure 8; thence overflowing it passes down the tube in the centre into
the inside of the scrubber, whence it is discharged on to the revolving
brushwood as the arms revolve. The water seal box contains sufficient
water to seal the vertical pipe; in this way the water is conveyed to the
interior of the scrubber and discharged at the ends of the three revolving
arms on to the revolving brushwood. Now, as the outer surface of the
space near the sides of the scrubber is much larger than the part
towards the centre, the revolving arms are made to travel slowly over:
their outer paths, as shown by dotted lines, Figure 4, by means of the
outer peripheries and teeth of the eccentric wheels by which the tubes
are turned round distributing a larger quantity of water at the part
where the surface requires it, and, in like manner, a less quantity of
water where needed.
By these improved arrangements I effect a distribution of water so
well regulated that the scrubber is fed with the smallest quantity of
water necessary to take up all the ammonia. This comparatively small
quantity of water becomes, as it descends in the scrubber, a highly
concentrated solution of ammonia, valuable as a marketable commodity, :
and producing a large profit upon gas works, and which being presented
in a proper state of division acts as a solvent for and takes up the

page_text: bisulphide of carbon and other impurities and acids, which it has been
found impracticable until now to remove from coal gas.
In witness whereof, I, the said William Thomas Walker, have hereto
set my hand and seal, this Seventh day of February, in the year of
our Lord One thousand eight hundred and seventy-two.
Witness,
W. A. GILBEE.
WILLIAM THOMAS WALKER. (L.S.)