IMPROVEMENTS IN AND CONNECTED WITH BLAST FURNACES AND OTHER FURNACES, AND COKING OVENS, RETORTS, AND OTHER GAS-PRODUCERS, AND IN THE MODe of, AND MEANS OR APPARATUS FOR PURIFYING THE GASES AND REMOVING THE VALUABLE PRODUCTS THEREFROM
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by John Arthur at the Office of the
Commissioners of Patents on the 10th May 1883.
JOHN ARTHUR of Harthill, in the County of Lanark, North Britain, Engineer,
"IMPROVEMENTS IN AND CONNECTED WITH BLAST FURNACES AND OTHER FURNACES,
AND COKING OVENS, RETORTS, AND OTHER GAS-PRODUCERS, AND IN THE MODe of,
AND MEANS OR APPARATUS FOR PURIFYING THE GASES AND REMOVING THE
VALUABLE PRODUCTS THEREFROM,"
"
This said Invention relates to improvements in the better and more economical
working of blast furnaces and other furnaces, by removing the back pressure of
their gases, and giving increased draught and a freer combustion with less
consumption of fuel, and greater immunity from explosions of the gases drawn
off when these are inflammable; also in improved arrangements of apparatus for
the better drawing off and purifying of these gases, for their subsequent
combustion and utilisation; and the more perfect separation of the valuable
soluble and condensible matters from these gases, such as the ammoniacal or other
soluble matters, and the oleaginous and tarry volatile and condensible matters, for
subsequent utilisation. These improvements are also applicable in whole, or in
part, to the treating of the waste gases from gas-works, oil-works, malleable-iron
works, collieries, factories, steam-ships, coking and calcining and other ovens and
fires, where coal, shale, and other combustibles are being burned.
By this Invention the waste gases from blast furnaces are as usual drawn off
from as near the top of the furnace as possible without interfering with the usual
charging bell or doors; and the gases from other furnaces with chimneys are
drawn off from a very high part of the chimney, which must be fitted with a
closing lid or valve above this point. In either case they are led direct and at
once into the top or upper part of a new or improved large and very high, hollow,
close, down-draught scrubber, or gas-washer and condenser, capable of freely
taking all the gases from the furnace, or chimney, to which it is fitted; all in
contradistinction to the methods heretofore in use of first leading the gases down
a gas main to near the ground level before treating them. This scrubber is fitted
with its lower open end over or in direct connection with a close receiving or water
cistern, through which the gases pass after being treated in passing down the scrubber.
.
1

page_text: Water is led or pumped to the top of this down-draught scrubber and admitted
in a regulated shower or spray by suitable openings and valves and it might be
by water dip jointed, or trapped annular or sectional openings, which would let
in the water freely in a shower, but would neither allow the gases to escape
nor admit the air from the outside. Where a large quantity of gas has to
be treated, or where extra purification of the gas is required in addition
to that effected in this very long down-draught scrubber, an extra duplex
set of scrubbers, of a lower or more moderate height, would be erected over
a continuation of the bottom receiver. The washing water with the ammonia
and condensed tar or other liquids would remain in the lower part of the
cistern and be drawn off at their respective levels, according to their specific
gravities, by suitable branches and valves or by siphon traps to prevent the escape,
of gas or admission of air, and lead them to suitable vessels for subsequent
treatment and utilisation. The gases so far purified would be led from the upper
part and first division of the receiving cistern up the hollow up-take intermediate
shaft of, and connected at the top to a second down-take shaft or scrubber
(separated from the former by a dip division in the cistern) and also fitted with
water supply pipe and regulating valve and spray openings similar to the first
scrubbers; and when not found to obstruct the free passage of the gases a less
shower or spray of water might also be provided for and let down the gas up-take
shaft. For the better cooling of the gases within these improved down-draught
scrubbers they would preferably be made of strong sheet iron or steel without the
brick linings heretofore used, but when found desirable they might be fitted with
transverse perforated or plain angled plates or conoidal discs and rings, which
would allow of a free passage of the gases down the shaft and spray the water at
these points, so that the gases would have to pass repeatedly through the spray,
and cause the water and tarry matters to flow freely off the angled surfaces of
these plates, which when found necessary, could be made portable for ease of
removal upwards or downwards, and removed in parts through side doors.
When this improved arrangement of scrubbers is fitted to blast furnaces, one
would preferably be fitted to each furnace and have a closing valve lid over the
top inlet from the furnace, which may be shut down by the same mechanical
arrangement which opened the charging bell or doors of the furnace (and vice
versa) to prevent explosions. And each scrubber being much smaller would be
more manageable than when made large ás heretofore for treating all the gases
from the main pipes of the several furnaces. The gases so purified would-be led
away by a pipe, from the first division of the receiving cistern and lower end of
the first down-draught scrubber, or from the second division when 'the second
scrubber is used, to the furnaces to be burned with air for the heating of the air
for the blast furnaces, or heating the boilers for raising the steam for the blowing
engines, or for other heating purposes.
A further improvement consists in fitting these waste gas-treating scrubbers and
their cisterns and gas-conducting pipes, applicable also to other such apparatus for
so treating and conducting inflammable gases, with light safety explosion or
man-hole doors to lift by the pressure of the explosion from within against their
guards and close automatically and instantaneously again by their own weight
within a cupped or rim seating which would contain and allow the joint of the
valve to be made tight by a few inches of water supplied to each by a regulating
tap, and having large or other overflow or trapped arrangement round the valve
seat to lead the water into the gas pipe or vessel on which the valve is mounted,
and so as to allow of a free relief of the pressure from within, and prevent the
inlet of the air from without.
In some cases where the gases (after passing through these improved arrange
ments of scrubbers) are mixed with an undue proportion of incombustible heavy
gases, vapour, or air, so that they cannot be burned for lighting or heating
purposes, they might by a further improvement, be led into the lower part of a
close vertical gas receiver fitted with a valve and a drawing-off pipe on top for

page_text: carrying off the light inflammable gases for distillation, or burning them at the
valve pipe, and with a pipe at the bottom of the holder for drawing off all the
heavy non-inflammable gases.
Although these new down-draught scrubbers have only been described for the
use of water in the treating of the gases passed through them for causing the
increased draught or suction of the gases from the furnace by the gravitation and
speed of the water falling through them, and for separating the soluble and
condensible matters from the gases, yet still it will be understood that these
improvements are equally applicable for giving the same advantages with the
scrubbers which use sulphuric acid or other chemicals with the water or sulphurous
vapours or other gases mixed with the gases to be treated either before or after
having passed through the first scrubber. In these applications the internal
surface of the scrubbers and plates would préferably be enamelled or lined with a
substance which would resist the chemical action of the acids used.