Improvements in Apparatus for Rendering Iron Blast Furnace Gases Available for Working Gas Motor Engines.
Year: 1896

page_text: Date of Application, 15th July, 1896--Accepted, 15th Aug., 1896
COMPLETE SPECIFICATION.
Improvements in Apparatus for Rendering Iron Blast Furnace Gases
Available for Working Gas Motor Engines.
We, BENJAMIN HOWARTH THWAITE of 29 Great George Street, Westminster
in the County of London, Civil Engineer and FRANK LACROIX GARDNER of
32 Old Jewry in the City of London, Mining Engineer, 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: -
In order to render blast furnace gases available for production of motive power
by acting in an internal combustion or gas motor engine, they have to be thoroughly
cleared from matters suspended-in them and regulated in pressure and volume to
suit the demand.
This invention relates to apparatus for this purpose, consisting of dust depositing,
cooling, washing, scrubbing and filtering apparatus, some of them preferably
arranged in duplicate with valves for alternating their action, so that the blast
furnace gases can be passed through the one set of apparatus while the other set
is being cleared of the deposited matters. The gases being drawn from the furnace
and propelled by a fan through the cleansing apparatus into a gas holder from
which they pass to the engine, a valve is provided to close the suction pipe of the
fan when the top of the furnace is opened for charging, and a self acting relief
valve is arranged to come into operation when the gas holder is fully charged to
allow escape of the surplus volume of gases, a water column and float are also
provided which makes an electric contact to signal the reduction of pressure in the
furnace when a tuyère happens to give way, so that the suction of the fan may be
at once reduced or entirely stopped in order to avoid the generation of an explosive.
mixture in the conduits.
Such being the general character of the apparatus, the arrangement and
construction of the several parts thereof will be described referring to the
accompanying drawings.
Figure 1 is a general plan of the whole apparatus.
Figure 2 is a part section of the top of the furnace, suction pipe and valve.
Figure 3 is a longitudinal section, Figure 4 is a transverse section on the
line 4-4 of Figure 3, and Figure 5 is a plan, partly in section of duplicate dust
depositing chambers.
Figure 6 is a longitudinal section and Figure 7 is a transverse section on the
line 7-7 of Figure 6 of the gas washing apparatus.
Figure 8 is a longitudinal section of the cooler.
Figure 9 is a vertical section of the scrubber.
Figure 10 is an elevation and Figure 11 is a plan of the duplicate gas filtering
apparatus of which Figure 12 is a transverse section drawn to an enlarged
scale.
Figure 12 is an elevation partly in section of the valves for alternating the
flow of the gases.
Figure 13 is an elevation partly in section of the relief valve 18 for the gas
holder.
Figure 14 is a vertical section of the water column and float for electrically
signalling.
As shown in Figure 1, 1 is the iron blast furnace, 2 the valve through which
the gases pass to a receiver 3, from which they pass to the dusting apparatus 4.

page_text: Thence they are led by pipe 5 to the fan. 6: From the fan they are propelled
either directly by pipe 7 to the washing apparatus 8, or by a by-pass pipe 10 first
through a cooler 11 to the washer 8. From the washer 8 the gases pass by pipe 12
to the scrubber 13 and thence through the duplicate filtering apparatus 14 to the
gas holder 15, from which a pipe 16 leads to the engine-17 which is indicated as
being a double cylinder or compound engine. 18 is the relief valve which allows
escape of gas when the holder 15 is quite charged. 19 is the water column and
float for signalling when a tuyère happens to give way.
Referring to Figure 2, to the stem of the bell hopper A which is worked by
lever B a chain C is attached passing over pulleys D, to the stem of a double
valve 2, consisting of the two valves on one stem E in a pipe F. G. which com-
municates by a lateral branch H with the upper part of the smelting furnace 1.
When the bell hopper A is closed as shewn, the valve 2 is in such a position that
the gases coming from the furnace through the branch H pass down the pipe G
which leads to the receiver 3. When the bell hopper A is lowered for the
purpose of feeding the furnace, the valve 2 is raised so as to close the pipe G
and allow the gases to escape up the pipe F, the closing of the pipe G preventing
the entrance of air which mixing with the furnace gases might produce an
explosive mixture.
Referring now to Figures 3. 4 and 5 shewing the dust depositing chambers 4,
the gases from 3 entering by the conduit A pass either of the two valves B Bi
into either of the two chambers C. C and thence by the corresponding valve D
or D and the outlet E to the conduit 5. In the chambers C. C are suspended
oblique screens F. F1 which are rapidly moved up and down by eccentrics or
cranks on an over head shaft moving their rods ff. Each of the screens F
or. F consists of two parallel webs of wire gauze the upper edges of which are
attached to a bar f; the ends of the bars as the screens rapidly descend strike
stops projecting from each side of the chamber C or C thus causing the dust
collected in the meshes of the screens to be shaken off. Each of the valves B. B¹,
DD is formed as a bell the edge of which dips into an annular trough H con-
taining mercury, forming a liquid seal when the valve is closed. Also the rods f./1
of the screens have fixed on them bells which dip into annular troughs containing
mercury of sufficient depth to allow for the vertical reciprocation of the screens.
The valves B. B' and D. D' have their rods also provided with bells dipping in
annular mercury troughs and the rods of each pair are attached to the ends of a
sway beam G, the two sway beams being fixed on one longitudinal shaft K. When
either of the pair of valves B. B is raised the other being at the same time
lowered, movement is communicated through the shaft K so that the norre-
sponding valve of the pair D or D is opened and the other closed. When
the gases have. for a time passed through one of the chambers C or C¹ depositing
dust therein, the valves are moved so as to direct the gases into the other chamber
while the former is being cleared of the deposited matter which is withdrawn
through side doors not shewn. Between the screens there are in the chambers
partitions L. L' extending about half way down so as to direct the gases obliquely
through the screens.
Mercury is described as the liquid seal for the valves and their stems, also for
the stems of the screens. Obviously other liquid such as water may be used
instead of mercury, the depth of immersion being sufficiently increased so as to
sustain the pressure of the gases which practically is equivalent to a few inches, of
water column.
In order to ensure more rapid and complete deposit of dust it is preferred to
provide to and along the screens insulated conductors with points by which
electrical sparks may be passed through the dust laden gases, these sparks having.
the known characteristic of causing rapid deposit of suspended particles. In order
to connect these conductors to suitable electric generators I make the stems f
of the screens tubular and lead down them a number of insulated wires, leading.to
points distributed over each of the two webs of which each screen consists.

page_text: Each of the wires that is connected to the one terminal of the electric generator
having its point projecting from the one web of the screen has directly opposite to
it a point of wire connected to the other terminal, so that whenever suitable
contacts are made externally a number of sparks pass from the one set of points to
the other set.
The fan 6, to which the gases, after deposit of dust pass by the conduit 5, is of
any known construction and is driven at such speed as to give the gases a pressure
of several inches of water column.
The gas washing apparatus 8, shewn in Figures 6 and 7, consists of a vessel A
having partitions B extending nearly to the bottom and dividing the vessel into
several chambers. The furnace gases enter from the conduit 7 by the inlet C
which dips into water occupying the lower part of the vessel; after bubbling
through the water they issue from the upper part of the first chamber and pass by
a bent conduit D to the next chamber where they bubble again through the water,
and so on from chamber to chamber until they issue by the outlet E to the
conduit 12. The bends of the conduits D rest on setting screws carried by cross
beams F so that they can be adjusted in height, and, in order to allow for this
adjustment, each limb of the conduits is provided with a bell dipping into a trough
of liquid forming a seal. The washing apparatus may be made in duplicate and
provided with valves like those described for the dust depositing apparatus so that
one set may be cleaned while the other coutinues in operation.
The cooler 11 as shewn in Figure 8 is a vessel A. having partitions B extending
down from the top to water which occupies the bottom of the vessel and into
which the lower edges of the partitions dip, so that gases, coming from the
fan 6 by the conduit 10 and entering by the inlet C, after passing the partition
issue by the outlet D to the conduit 7 leading to the cooling apparatus 8. By
opening a valve G in the conduit 7 and closing a valve H on the by-pass 10 the
gases are made to pass directly to the cooling apparatus 8 by closing G and
opening H they are made to pass through the washer 11 ou their way to the
cooling apparatus 8.
The washed gases pass from 8 to the scrubber 13 shewn in Figure 9. It consists
of a tower A divided into compartiments by gratings or perforated plates B on
which is piled coke kept moistened by a shower of water from a perforated pipe C
at the top of the tower. The gases entering by the inlet D rise through the
interstices of the wetted coke and issue at the top by the outlet E passing on to
the filter 14.
The filter shewn in Figures 10. 11. 12 and 124 is made in duplicate with aiter-
nating valves arranged as described with reference to the dust collecting
apparatus 4. Each of the two filtering chambers A. A' is constructed as shewn in
Figure 12. It is made with a removable cap a wnich has its margin dipping into
liquid in a trough a', the pipe A2 leading from the cap having a bell dipping into
liquid in a trough a². From the cap a descends a filter having its outer walls B of
perforated metal and having inner walls B' also of perforated metal, or it might
be wire gauze, and, between the outer and inner walls, filtering material such as
sawdust. In order to give access for cleaning or changing the filtering material,
the cap a is raised by overhead tackle, raising the filter with it. In the automatic
gas regulating apparatus shewn in Figure 13, A is the bell of the gas holder from
which gas is taken to the engine. Round a pulley B carried by a bracket pro-
jecting from the bell A passes a chain C tightened by a weight.c. This chain
passing over suitable guide pulleys and a pulley D is connected to the stem of a
valve E which is counterbalanced by a weight c. The valve E is formed as a
bell dipping into liquid in an annular trough e. Also on the valve stem is a bell F
dipping into liquid in an annular trough f. When the bell A attains a certain
height it raises the valve E allowing gas to escape from the conduit leading from
the fan. But so long as no more gas is supplied to the holder than is consumed
by the engine, the bell A occupies a lower position, the valve E remaining
closed.

page_text: The apparatus, Figure 14, for electrically signalling to the engineer or attendant
on the engine and fan when the pressure in the furnace varies beyond certain
predetermined limits-consists of a pair of pipes A B connected together at the
bottom and charged with a quantity of water, the pipe A communicating at C with
the pipe which conducts the gases from the furnace, and the pipe B having in it a
float D the stem of which passes through a guide at the top of the pipe B, and is
connected to a rod E of insulating material, which, as the float D ascends and
descends, slides between two pairs of contact springs F. G and H. K. Through
the insulating material passes a piece of metal M, which when it comes between
either pair of the springs closes the circuit of which they form part, this circuit
including a battery and any known visible or audible electrical signalling instru-
ment, both signals being preferable. When the circuit of F and G. is closed, the
current takes the one direction, when the circuit of H and K is closed, the current
is reversed. Thus if owing to the reduction of pressure in the gas duct and furnace,
the float D descends so far as to bring the metal M, down to the springs F. G, a circuit
is closed which causes an audible signal such as a bell to sound and an index to be
-deflected to one side indicating too great reduction of pressure. If on the other
hand, the pressure in the gas duct and furnace is so far increased that the float
rises enough to bring the metal M between the springs H K then the audible
alarm is sounded and the index is deflected in the opposite direction indicating
excess of pressure.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed we hereby declare that
we make no general claim to apparatus constructed and arranged as described in
the prior Specification No. 8670 of 1894, but what we claim is:-
1. For rendering iron blast furnace gases available for production of motive
power, the combination of a double valve connected to the bell hopper of the
furnace a duplicate dust collecting apparatus, a washing and cooling apparatus, a
scrubber and duplicate filter, a gas holder with regulating valve, an internal
combustion engine and a fau, also an electric alarm, arranged and operating
together substantially as described.
2. The double valve connected to the bell hopper substantially as described with
reference to Figure 2.
3. The duplicate dust depositing apparatus, substantially as described with
reference to Figures 3. 4 and 5.
4. The washing apparatus substantially as described with reference to Figures 6
and 7.
5. The duplicate filtering apparatus substantially as described with reference to
Figures 10. 11. 12 and 124.
6. The automatic gas regulating apparatus, substantially as described with
reference to Figure 13.
7. The electrically signalling apparatus substantially as described with reference
to Figure 14.
Dated this 15th day of July 1896.
ABEL & IMRAY,
Agents for the Applicants.