IMPROVED APPARATUS FOR PURIFYING ILLUMINATING GAS
Year: 1878

page_text: LETTERS PATENT to William Thomas Sugg, of Vincent Street, in the City of
Westminster, for the Invention of "IMPROVED APPARATUS FOR PURIFYING
ILLUMINATING GAS."
Sealed the 25th June 1878, and dated the 8th January 1878.
PROVISIONAL SPECIFICATION left by the said William Thomas Sugg at
the Office of the Commissioners of Patents on the 8th January 1878.
WILLIAM THOMAS SUGG, of Vincent Street, in the City of Westminster.
PROVED APPARATUS FOR Purifying ILLUMINATING GAS."
"IM-
The object of this Invention is to provide a facile means for carrying out the
purifying process for which a Patent has been applied for by me in conjunction
with Frederick John Evans, September 12th 1877, No. 3445. This process con-
sists in submitting the gas as it leaves the retorts to ammonia, either in the gaseous
or liquid form, to neutralize the acid impurities in the gas. These acids require
the
presence of water for their absorption, and it has been found that this water
requires constant renewal to secure this result. I now construct an apparatus for
receiving the gas and presenting to it a continuous stream of water or ammoniacal
liquor, which, as it becomes charged with the impurities of the gas, will flow off
with the deposited tar to any suitable receptacle.
The apparatus is by preference made in three divisions, that which receives the
liquor being at the highest, and that which is in connection with the gas supply
pipe at the lowest. This pipe leads the gas up to the top of the compartment,
whence it descends by a dip pipe and bubbles through the liquor or liquid which
seals this pipe, depositing the greater portion of the tar which comes over with it,
and leaving absorbed in the liquor the greater portion of the gaseous impurities.
The gas is then guided upwards by a pendent partition plate to a passage communi-
[Price 8d1

page_text: cating with a dip pipe in the second compartment. From the bottom of this pen-
dant pipe the gas escapes bubbling through the liquor as before, and leaving therein
a further portion of its impurities. The gas then passes in like manner into the
third compartment, where it deposits the remainder of its impurities in the liquor,
which meets it fresh from the supply pipe. The purified gas is led off from this
third compartment to the gasometer, it being if required passed through a scrubber
to cool it, and otherwise treated to separate the ammonia therefrom.
From the floor of the first and second compartments rise plates, which serve to
gauge the height of the liquor therein and regulate the downward flow of the
liquor, which is always subjected to the pressure of the gas. Each compartment
is provided with a discharge pipe for removing the tar deposited therein and
running it into suitable receptacles.
The tar as it is deposited in the first compartment I run off continuously with
the foul liquor by means of a syphon pipe, providing however suitable means for
maintaining in that compartment the requisite level of liquor for sealing the dip
pipe.
I would remark that the compartment which first receives the gas may extend
from end to end of the bed of retorts, or if desired the retorts may discharge into
a main pipe, and the first compartment may be connected with the end of the main
pipe. The first arrangement is however preferred where the gas works will admit
of its adoption.
By drawing off the tar at two or more stages of the purifying operation I am
enabled to obtain tars of different qualities and suitable for different uses.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Thomas Sugg in the Great Seal Patent Office on the 8th
July 1878.
WILLIAM THOMAS SUGG, of Vincent Street, in the City of Westminster. "IM-
PROVED APPARATUS FOR PURIFYING ILLUMINATING GAS."
The object of this Invention is to provide a facile means for carrying out the
purifying process for which a Patent has been granted to me in conjunction with
Frederick John Evans, bearing date September Twelfth One thousand eight hundred
and seventy-seven, No. 3445. This process consists in submitting the gas as it
leaves the retorts to ammonia, either in the gaseous or liquid form, to neutralize
the acid impurities in the gas. These acids require the presence of water for their
absorption, and it has been found that this water requires constant renewal to
secure this result. To this end I now construct an apparatus for receiving the gas
and presenting to it a continuous stream of water or ammoniacal liquor, which
as it becomes charged with the impurities of the gas will flow off together with
the deposited tar into suitable receptacles.
The apparatus is by preference made in three divisions, that which receives the
liquor being at the highest, and that which is connection with the gas supply
pipe at the lowest. This pipe leads the gas up to the top of the compartment,
whence it descends by a dip pipe and bubbles through the liquor or liquid which
seals the pipe, depositing the greater portion of the tar which comes over with it,
and leaving absorbed in the liquor the greater portion of the gaseous impurities.
The gas is then guided upwards by a pendent partition plate to a passage communi-
cating with a dip pipe in the second compartment. From the bottom of this
pendent pipe the gas escapes bubbling through the liquor as before, and leaving
therein a further portion of its impurities. The gas then passes in like manner into
the third compartment, where it deposits the remainder of its impurities in the liquor
which meets it fresh from the supply pipe. The purified gas is led off from this
third compartment to the gasometer, it being if required first cooled by being passed
through a scrubber, and otherwise treated to separate the ammonia therefrom.
From the floor of the first or highest compartment, and also the second, rise
partitions, which serve to gauge the height of the liquor therein, and regulate the
downward flow of the liquor, which is always subject to the pressure of the gas,
Each compartment is provided with a discharge pipe for removing the tar deposited
therein and running it into suitable receptacles.
The tar as it is deposited in the lowest compartment I run off continuously with
the foul liquor by means of a pipe, providing however suitable means for main-
taining in that compartment the requisite level of liquor for sealing the dip pipe.
I would remark that the compartment which first receives the gas may extend
from end to end of the bed of retorts. In other words the.hydraulic main may form
the lowest of the series of purifying compartments, or if desired the retorts may
discharge into a main pipe, and the lowest compartment of the series may be con-
nected with the end of that main pipe. The first arrangement is however preferred
where the gas works will admit of its adoption.
By drawing off the tar at two or more stages of the purifying operation I am
enabled to obtain tars of different qualities and suitable for different uses.
In the accompanying Drawings, Fig. 1, Sheet I., shews in longitudinal section
one of a series of through retorts A, fitted at its opposite ends with ascension
pipes B that lead to hydraulic mains C, as commonly used in gas works. These
mains I now connect by pipes D, D, (capable of being shut off by stop cocks) with
a vessel E, into which the tar deposited by the gas in its passage through the
hydraulic mains is discharged instead of being allowed to accumulate, as at present,
in the mains. This vessel E also receives the liquor used in purifying the gas, and
from it both the liquor and the tar are discharged by means of overflow pipes, as

page_text: will be hereafter more particularly explained. In connection with each of these
hydraulic mains C, C, is a purifying apparatus similar to that shewn in longitudinal
sectional elevation at Fig. 2. which apparatus I employ for subjecting the gas while
in a heated state to the action of ammonia. In this Figure, B represents the dip
of one of the ascension pipes, and C, the end of the hydraulic main, into which the
hot gas from the retorts is conducted, as indicated by the arrows in Fig. 1. F is
an inclined chamber divided by partitions f into compartments 1, 2, and 3, which
compartments communicate with each other and with the hydraulic main by means
of dip pipes g. These pipes are sealed by liquid ammonia, which is supplied
thereto by a pipe h entering the compartment 1, the same being derived from the
pumping apparatus connected with an ammoniacal liquor tank. The compartments
also connect with each other by openings in the partitions ƒ near the floor of the
chamber; and each compartment is fitted with an overflow plate i, which plates
keep the liquor to the required level in the several compartments, and allow of the
descent of the liquor as the supply is continued from the highest compartiment to
the lowest, and thence to the hydraulic main, from which it is discharged into the
closed receiver or tank E, Fig. 1.
The gas as it leaves the retorts will retain its heat while passing up the pipes B by
reason of such pipes being clothed with non-conducting material (such as is used for
clothing steam beilers), or otherwise protected from the cooling action of the atmo-
sphere. This clothing is indicated by dots at b, b, Fig. 1. The gas will thus enter the
main at a temperature of some two hundred degrees, or in a condition best adapted
for the efficient action of the ammonia thereon. It will then pass from the hydraulic
main through the several compartments of the chamber F, as indicated by the
arrows, and in so doing it is caused to bubble through the ammoniacal liquor con-
tained therein, leaving behind it the tarry products of the coal; the first discharge
being, as before mentioned, into the vessel E, the second into a chamber 3*
forming an extension of the compartment 3, the third into a chamber 2*, being
an extension of the compartment 2, and the fourth (if any tar still remains in the
gas) into the chamber 1* of the compartment 1. Thus no accumulation of tar is
allowed to interefere with the free passage of the gas, and as ammonia is freely
supplied to the chambers through which it has to pass the removal of the carbonic
acid and the sulphur impurities contained in the gas is ensured. As the liquor
becomes saturated with impurities it is run off from the main, and is replaced by the
downflow of purer liquor from the compartments of the chamber F, a supply of
pure liquid ammonia to that compartment being maintained during the process of
purification.
Connected with the compartment 1 of the chamber F is a pipe G, which carries
off the gas as it is purified and conducts it to the scrubbers, where its temperature
will be reduced, and it will be rendered fit to enter the gas holder. It may
however be desirable to pass the gas through an oxide of iron purifier in case the
neutralization of the sulphur acids is not complete. The gas on leaving the
chamber F should not exceed a temperature of one hundred degrees Fahrenheit.
From the foregoing explanation it will be understood that the gas in its most
impure state will be caused to give up the greater part of its impurities in the
hydraulic main, when that is adapted to form a part of my improved purifying
apparatus.
The next most copious deposit of impurities will take place in the compartment 3,
and so on, reducing its deposit as it proceeds upwards. The gas as it ascends and
becomes more pure by traversing through the descending liquor will flow through
a purer stream, escaping finally in a purified state into the pipe G.
As the overflow foul ammoniacal liquor runs from the hydraulic mains it will carry
with it into the tank E the tar, which would otherwise deposit in and ultimately
choke up the mains. In order to draw off this tar from the tank, and also the foul
ammoniacal liquor, without however reducing the water level in the hydraulic
mains, the stand pipes E¹, E2, are used. The stand pipe E¹ is tapered at its lower

page_text: part and extends to near the bottom of the tank, leaving a free space for the tar
(which is heavier than the water, and deposits at the bottom of the tank) to flow
into the stand pipe.
The pressure of the head of water above the tar will cause the tar to ascend
the pipe E¹, and discharge through its spout into a funnel connected with one of a
series of tar tanks.
The stand pipe E2, which connects with the top of the tank E, rises above the
stand pipe E and discharges from its spout the foul liquor at about the level at which
it is desired to maintain the liquor in the hydraulic main. From this pipe it is
conducted off to any suitable receiver to be purified and again used in the purifying
apparatus.
The tar received into the several chambers 1*, 2*, 3*, is discharged therefrom in
the same manner as was described with reference to Fig. 1. The form and fittings
of these chambers is clearly shewn in the transverse section, Fig. 5, hereafter
referred to.
Fig. 3 shews in sectional elevation, and Fig. 4 in plan view, a modification of the
above described apparatus adapted for gas works, in which no hydraulic main is
used, and adapted also for the employment of ammonia in the form of vapour, or
it may be in the form of spray. In this instance each ascension pipe B is connected
directly with the chamber F, which is, except in capacity breadthwise, similar to
that described with reference to Fig. 2.
A transverse section of this chamber is shown at Fig. 5, which serves also to
explain the construction and mode of fitting the several compartments of Fig. 2,
the lower divisions of which have their floor inclined in order that the tar may
accumulate at one side thereof.
In the modified arrangement of Fig. 3 water is admitted by the pipe h, and the
ammonia is supplied from a pipe H having branches H₁, which lead respectively
into the compartments 2 and 3 of the chamber F. Thus the gas becomes com-
mingled with the ammonia before passing into the liquor in the lowest com-
partment, and it is caused to yield up a large proportion of its impurities, after
which its progress through the middle and highest compartment completes its
purification.
Fig. 6 shews in vertical section a modified form of the apparatus, whereby the
tar is drawn off from the hydraulic main. In this example the closed vessel E
instead of being provided, as at Fig. 1, with a stand pipe for running off the tar, is
coned at its lower end and fitted with a valve seat, in connection with which is a
discharge pipe E'. The tar as it is deposited in the hydraulic main C is conducted
by the inclined pipe D to the bottom of the vessel E, where it accumulates below
the liquor which runs with it into the vessel E until the level of the liquor in the
hydraulic main and vessel E rises above a certain point. The vessel E is connected
by a pipe Es with the upper part of the hydraulic main in order that the pressure
on the liquor may be the same in the main and in the vessel E. Fitting the seat
in the bottom of the vessel E is a valve E³, which is connected by a rod to a
float E. As the liquor accumulates in this vessel the float will be raised and the
accumulated tar discharged down the pipe E' into any suitable receiver.
Fig. 7 shews in vertical section a further modification of the apparatus for
discharging the tar from the hydraulic main. In this example the pipe D discharges
the tar and liquor directly into a funnel connected with a receiver. The pipe D
is fitted with what is known as a slicer D¹, which by dropping over the discharge
opening in the side of the pipe serves to close it. The valve D¹ is carried by a
rock lever, which is actuated in the following manner; E is a closed vessel, con-
nected at top and bottom by tubes with the hydraulic main C. The vessel E is
divided horizontally into two parts by a flexible diaphragm E¹, and from the
centre of this diaphragm rises a rod, which passing through a stuffing box in the
cover of the vessel E connects with one end of a lever E' mounted on a pillar carried
by the cover of the vessel E. The other end of this rock lever E' is connected by
a pendent rod with the rock lever carrying the valve D'. As therefore the level

page_text: of the liquor in the vessel E varies the diaphragm E' will be either raised or
depressed, and a rocking motion will thus be given to the lever E², and simul-
taneously to the valve lever. By this means the slicing valve D¹ will be caused to
open or close the pipe D, and to effect an intermittent or continuous discharge of
the tar from the hydraulic main.
Having now set forth the nature of my Invention of "Improved Apparatus for
Purifying Illuminating Gas," and explained the manner of carrying the same into
effect, I wish it to be understood that under the above in part recited Letters
Patent I claim, the arrangement of apparatus above described, whereby a con-
tinuous stream of water or ammoniacal liquor may be presented to the gas on its
passage from the retorts, and caused to take up the acid impurities of such gas and
carry off the same to a suitable receiver, the tar being at the same time thrown
down and discharged from the apparatus, as and for the purpose above explained.
In witness whereof, I, the said William Thomas Sugg, have hereunto set my
hand and seal, the Fifth day of July, in the year of our Lord One thousand
eight hundred and seventy-eight.
WILLIAM T. SUGG. (L.S.)