IMPROVEMENTS IN HYDRAULIC MAINS FOR GAS WORKS
Year: 1885

page_text: I, CHARLES DENTON ABEL of No 28 Southampton Buildings Chancery Lane in
the County of Middlesex, Consulting Engineer and Patent Agent, do hereby declare
the nature of my invention for "IMPROVEMENTS IN HYDRAULIC MAINS FOR GAS
WORKS" to be as follows:-
Little or no attempt has heretofore been made to utilise the condensing action
that the hydraulic mains in gas works could exercise upon the more easily con-
densible products of distillation; on the contrary, endeavours have mostly been
directed towards diminishing the resistance of the liquid in the hydraulic main to
the passage of the gas by reducing as much as possible the depth to which the
ascension pipe is immersed therein. The tar and the ammoniacal liquor, being of
different densities, become stratified in the hydraulic main so that after a short
time, as the volume of tar increases, the ascension pipe only dips in the latter
which, under the action of the heat from the furnaces, becomes more or less
converted into pitch requiring very frequent cleansing operations to be resorted to.
According to the present invention this disadvantage is avoided and as much tar
and ammoniacal liquor are retained in the hydraulic main by fixing to the dip pipe
of the ascension pipe horizontal sieve-like plates situated beneath the water level
in the hydraulic main and so arranged as to subdivide the gas issuing from the dip
pipe and to cause it to travel a long distance in contact with the water. Further-
more, instead of arranging the lowest point of the discharge pipe at the level of the
liquid in the hydraulic main, it is placed a small distance below it, and there is
fixed in front of it a vertical plate, the upper edge of which is at a height corre-
sponding with that of the level of the liquid, while its lower edge is at a slight
distance from the bottom of the main. By this arrangement the tar is made to
flow off simultaneously with the ammoniacal liquor and a constant depth of the
liquor is thus maintained, and the necessity for frequent cleansing is also avoided.
The said sieve-like plates are by preference arranged as follows:-A plate having
flanges extending downwards is secured in an adjustable manner by screws or
D
877

page_text: otherwise to the dip pipe, at a point just below the level of the liquid in the main,
and a second plate with similar flanges is fixed within the first named one, at the
same level as the orifice of the dip pipe. The lower plate has perforations on one
side thereof and the upper plate has perforations on the opposite side, so that the
gas on issuing from the dip pipe has first to travel along the underside of the lower
plate to the perforations thereof and after rising through these, it has to travel
along the underside of the upper plate in order to rise through its perforations into
the gas space of the hydraulic main. A perforated shield also projects down from
the upper plate, through which the gas has to pass on its way to the perforations,
so as to become still further subdivided.
By thus bringing the gas into prolonged intimate contact with the liquor in the
main, a large portion of the more condensible constituents thereof will become
condensed in this liquor.
Instead of employing only two sieve-like plates three may sometimes be
employed, one below the other, and with the perforations at opposite sides, so that
the
gas has to pass in a zig-zag direction from one to the other. These plates may
be supported from the sides of the hydraulic main instead of to the dip pipe.

page_text: Improvements in Hydraulic Mains for Gas-works.
I, CHARLES DENTON ABEL, of No 28 Southampton Buildings, Chancery Lane in
the County of Middlesex, Consulting Engineer and Patent Agent, do hereby declare
the nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:-
Little or no attempt has heretofore been made to utilise the condensing action
that the hydraulic mains in gas works could exercise upon the more easily con-
densible products of distillation; on the contrary, endeavours have mostly been
directed towards diminishing the resistance of the liquid in the hydraulic main to
the passage of the gas by reducing as much as possible the depth to which the
ascension pipe is immersed therein. The tar and the ammoniacal liquor, being of
different densities, become stratified in the hydraulic main so that after a short
time, as the volume of tar increases, the ascension pipe only dips in the latter,
which, under the action of the heat from the furnaces, becomes more or less
converted into pitch, requiring very frequent cleansing operations to be resorted to.
According to the present invention this disadvantage is avoided and as much tar
and ammoniacal liquor are retained in the hydraulic main by fixing to the dip pipe
of the ascension pipe horizontal sieve-like plates situated beneath the water level
in the bydraulic main and so arranged as to subdivide the gas issuing from the dip
pipe and to cause it to travel a long distance in contact with the water. Further-
more, instead of arranging the lowest point of the discharge pipe at the level of the
liquid in the hydraulic main, it is placed a small distance below it, and there is.
fixed in front of it a vertical plate, the upper edge of which is at a height corre-
sponding with that of the level of the liquid, while its lower edge is at a slight
distance from the bottom of the main. By this arrangement the tar is made to
flow off simultaneously with the ammoniacal liquor and a constant depth of the
liquor is thus maintained, and the necessity for frequent cleansing is also avoided.
The invention will be readily understood on reference to the accompanying
drawings in which Figs. 1, 2 and 3 shew respectively a cross section, part longi-
tudinal section and part plan of a hydraulic main while Fig. 4 shews a modification.
of the screen device. Each dip-pipe B of the hydraulic main D has a screening
device A which is fixed to it by means of screw bolts a a, or by other means.
screening device consists of two horizontal plates b b¹ having flanges at the sides
for preventing the escape of the gas at those points and forcing it to pass through
the perforations c c formed at the opposite ends of the plates 6 6¹. The lower
plate b has perforations of about 6 millimetres in size while the upper plate 6¹ has
perforations of about 4 millimetres and between the two perforated plates is placed
a third plate d inclined at an angle and having perforations of about 6 millimetres
in size.
This
The gas entering through the dip-pipe B passes first through the perforations of
the plate 6 to the left hand of the pipe and afterwards passes from left to right:
underneath the plate b through the perforations in the shield d and then through.

page_text: the perforations in the plate 6¹, from which it passes into and bubbles up through
the water E in order to pass away through the pipe C.
By means of this arrangement there is retained in the hydraulic main a large
portion of the condensible products of the gas which is of great importance for the
application of gas works to work shops where the great cost of condensers, such as
are employed in gas works, forms an obstacle to their adoption.
In order to ensure that the dip pipe B shall always dip into the water of the
hydraulic main, the the lowest point of the overflow pipe F, instead of being placed
at the level of the water in the hydraulic main, is placed a small distance, such as
about 4 centimetres, below the same, and a plate H, fixed to the hydraulic main,
rises above this level to the level at which the water is to stand in the hydraulic
main while the lower edge of the said plate stops short some distance from the
bottom thereof.
As soon as the tar E¹, condensed in the bydraulic main, reaches the bottom of
this plate H all the tar will flow under the lower edge of the plate, while the water
will flow over the upper edge; thus a difference of level of 4 centimetres between
the lowest point of the pipe F and the upper edge of the plate H will ensure a depth
of water of 24 centimetres above the level of the tar E, which water is continually
renewed, carrying with it the ammonia and other watery vapours contained in the
gas. This water indicates 2° Baumé above the waters coming from ordinary
hydraulic mains. The screening device A should be as large as the distance
between the several dip pipes in the hydraulic main will permit of. If it can be
made of a width of 41 centimetres, the distance between the screening plates may
be reduced to 35 centimetres. The apparatus should be made as wide as the width
of the hydraulic main will permit of, as the longer it is made, the greater will be
the distance the gas has to travel before issuing from the water, and consequently
the greater will be the condensing action.
With this apparatus there may be retained in the hydraulic main 90 per cent of
the tar produced, and the formation of pitch will be avoided as the tar will always
flow away through the underside of the partitions H in the liquid state. By this
means an increase of from 4 to 5 per cent. will be obtained in the illuminating
power of the gas.
The effective contact between the water and the liquors in the hydraulic main is
shewn by the fact that the gas which enters the hydraulic main at about 70° C.
passes therefrom at a temperature of about 39°.
If, in consequence of the low temperature of the surrounding air or of an
abundant spraying with ammoniacal water, the temperature of the liquids in the
hydraulic main are kept below 30° C, a quantity of ammonia will be obtained that
will exceed that produced by the best construction of washers.
In the modification shewn at Fig. 4, the screening apparatus A consists of three
parallel screening plates b b¹ d arranged at distances of 2 centimetres from each
other. These plates are perforated over about of their length and are provided
with vertical flanges as in the previous case. The plates are perforated alternately
at opposite ends so as to force the gas to pass in a zig-zag direction from one to the
other, so as to be brought in extensive contact with the water of the hydraulic
main as indicated by the arrows. Instead of fixing the screening apparatus A to
the dip pipe B, it may be carried by angle irons fixed at a suitable height on the
sides of the bydraulic main. In all cases the perforated plates must be arranged in
horizontal positions the lower one b being on a level with the orifice of the dip
pipe B.
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
1. The use, in combination with the hydraulic mains for gas works, of apparatus
consisting of a combination of perforated metallic plates, so arranged in combina-
tion with the dip pipe, that the gas on issuing from the latter is caused to pass in.

page_text: a zig zag direction from plate to plate through the perforations, whereby it is
brought into extended contact with the water of the hydraulic main so as to cause
the greater part of the ammoniacal and tarry constituents to be condensed therein,
substantially as herein described.
2. In combination with a hydraulic main having screening apparatus arranged
as set forth in the preceding claim, the use of a vertical partition at the end of the
hydraulic main having its upper edge somewhat above the lower part of the over-
flow pipe, while its lower edge is some distance from the bottom of the hydraulic
main, so that the tar will find its way under the lower edge of the partition to the
overflow pipe, while the water will find its way thereto over the upper edge of the
partition, substantially as herein described.