KR101412355B1 - Testing apparatus for blast furnace - Google Patents

Abstract

The present invention relates to a device to test the operation of a blast furnace comprising a gas discharge pipe member to discharge gas to the upper part of a blast furnace body member for a test which simulates the operation of a blast furnace by charging the raw materials and fuel for a test therein, and supplying hot air thereto. The present invention can control the internal pressure of the blast furnace body member (10) for a test to form a stable temperature range by controlling the amount of gas discharged through the gas discharge pipe member with a control valve.

Description

[0001] TESTING APPARATUS FOR BLAST FURNACE [0002]

The present invention relates to a blast furnace operation test apparatus, and more particularly, to a blast furnace operation test apparatus capable of clearly confirming the behavior of a solid and liquid gas phase of a charge charged in a blast furnace by simulating actual blast furnace operation.

Generally, in the blast furnace operation, the iron ores or sintered ores that are charged into the upper part of the blast furnace are melted by the hot wind supplied through the tuyeres to produce melts (molten iron and slag), and the melts accumulated in the furnace are continuously .

Coke is used as a heat source in blast furnace operation. Coke is a raw material used as a heat source for blast furnaces and also serves as a reducing agent for reducing iron ores.

In the blast furnace operation, cokes, iron ores or sintered ores are charged alternately as described above, and hot air is supplied to the lower part of the furnace to produce molten iron.

The present invention and related prior art are disclosed in Korean Patent Laid-Open No. 10-2012-0023057 (March 12, 2012, blast furnace operation method).

An object of the present invention is to provide a blast furnace test apparatus capable of stably testing the actual blast furnace operation under various conditions by confirming the actual loading behavior of the blast furnace.

An object of the present invention is to provide a fuel cell system including a fuel cell, a fuel cell, a fuel cell, and a fuel cell.

A test furnace body member having a hollow space for loading the test raw material charge discharged from the charging hopper member and a space for loading the test fuel charge therein and having a transparent portion on either the front surface or the rear surface for inspecting the inside thereof;

A heating air supplier connected to a lower side of the test body body member for supplying heated air into the test body body member;

A gas discharge pipe member provided on an upper side of the test blast furnace body member;

A control valve for controlling an amount of gas discharged to the gas discharge pipe member; And

And a blast furnace operation test device including an artificial core member arranged at a lower portion of the blast furnace body member.

The present invention has the effect of clearly recognizing the behavior of solid, liquid, and gas in actual blast furnace operation by similarly reproducing soft welded joints in actual blast furnaces.

The present invention is also capable of observing the behavior of the furnace dust generation and similarly simulating the pressure loss trend in the direction of the height of the blast furnace.

The present invention is capable of quantitatively evaluating the effects of in-furnace dusting due to the actual amount of pulverized coal injected and capable of localized accumulation control by radial position.

The present invention prevents the occurrence of a load drop phenomenon due to the difference between the hopper for storing and discharging the charge and the internal pressure of the apparatus during the continuous charging of the charge, and makes it possible to stably perform the continuous blast furnace operation test.

The present invention can similarly reproduce actual blast furnace operation, accurately test blast furnace operation under various conditions, and provide reliable test data, thereby solving the problems in practical blast furnace operation.

1 is a schematic view showing a blast furnace operation test apparatus according to the present invention;
Fig. 2 is a schematic view showing a loading apparatus for testing in a blast furnace operation test apparatus according to the present invention.
3 is a perspective view showing a test body body member in a blast furnace operation test apparatus according to the present invention;
4 is a cross-sectional view of the test body body member in the blast furnace operation test apparatus according to the present invention
5 is a cross-sectional view showing the fuel charge water supply device in the blast furnace operation test apparatus according to the present invention
FIG. 6 is a cross-sectional view showing a charging water discharging device in the blast furnace operation test apparatus according to the present invention

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIGS. 1 and 2, the blast furnace operation test apparatus according to the present invention includes a test furnace body member 10 having a space portion formed therein.

In the upper part of the blast furnace body member 10, a test material feed and a test fuel feed are stored, and a test feed material and a charge hopper member 22, 23 are disposed.

The test body body member (10) comprises a blast furnace body portion (11) having an open top and a transparent portion (11a) on either the front side or the rear side so that the inside can be recognized; And

And an open end body portion 12 provided at an upper portion of the blast furnace body portion 11 and connected to the charging hopper members 22 and 23.

A gas discharge pipe member (12a) is provided in the open end portion (12) to discharge gas generated in the blast furnace body portion (11) during a blast furnace simulation test.

The gas discharge pipe member 12a is equipped with a control valve 12b for discharging gas generated in the blast furnace body 11 during the blast furnace simulation test and for controlling the amount of discharged gas. The control valve 12b controls the pressure in the blast furnace body 11 by controlling the amount of gas discharged to the gas discharge pipe member 12a and controls the pressure in the blast furnace body 11 during blast- Control the pressure. The gas discharge pipe member 12a is preferably provided with a furnace pressure sensor unit 12c for measuring the furnace pressure of the test furnace body member 10.

It is further preferable that a blower 12d for discharging the air in the test body body member 10 to the outside is provided on the discharge port side of the gas discharge pipe member 12a. The control valve 12b, the furnace pressure sensor unit 12c and the blower 12d are connected to the furnace pressure control unit 12e and are connected to the control valve 12c according to the furnace pressure sensed by the furnace pressure sensor unit 12c. 12b or the blower 12d to control the amount of gas discharged through the gas discharge pipe member 12a to adjust the internal pressure of the test furnace body member 10. [

It is necessary to be able to control the pressure or flow rate of the gas rising inside the test furnace body member 10 in order to simulate the softened welded joint during the blast furnace simulation test. That is, the amount of gas discharged through the gas discharge pipe member 12a is controlled to control the internal pressure of the test body body member 10 to form a stable temperature section, and the test body body member 10, It is possible to smoothly transmit the charge to the charging object and to form the equilibrium temperature zone in the inside of the container even when the charge is continuously supplied from the upper portion.

The charging hopper members 22 and 23 include a raw material storage hopper member 22 on which a first inlet 22a is formed at an upper portion and a first outlet 22b for discharging a raw material charge stored at the lower portion is formed;

A fuel storage hopper member (23) in which a second inlet (23a) is formed in an upper portion and a second outlet (23b) for discharging a test fuel charge stored in the lower portion is formed; And

The test material feed or test fuel charge discharged through the first outlet 22b and the second outlet 23b flows into the inside and the outlet 25a is provided at the lower portion. And an intermediate hopper member (25) connected thereto.

The intermediate hopper member 25 is connected to the openable body portion 12 and charges the test material charge and the test fuel charge into the space portion through the discharge port 25a.

In addition, a charging guide hopper 21a is provided on the upper part of the charging hopper members 22 and 23, and a first charge charging port 21b for discharging test charging materials and a charging / And a dispensing hopper member 21 in which a two-piece water discharging opening 21c is provided at the bottom. The first charge outlet 21b is connected to the first inlet 22a and the second charge outlet 21c is connected to the second inlet 23a.

Inside the dispensing hopper member (21) is provided a distribution plate member (24) rotatably mounted. The distribution plate member rotates to guide the test material stock charged through the charging guide hopper 21a toward the first charging port 21b and guide the test fuel charge to the second charging port 21c do.

The first outlet 22b, the second outlet 23b and the central outlet 25a are provided with an opening and closing door (not shown), respectively. The first outlet 22b, the second outlet 23b, And the discharge of the test raw material charge or the test fuel charge discharged through the central discharge port (25a).

A charging device for testing that charges the test material charge or test fuel charge discharged through the discharge port of the intermediate hopper member (25) into the space portion is provided in the openable body portion (12).

The charging instrument for testing includes a charging guide shoe member (20), a charging guide shoe member (27) disposed in the openable body portion (12) and having a bell shape gradually expanding from the upper portion to the lower portion.

The charge guide chute member 27 has a shape gradually increasing in both sides toward the lower side to guide the test material charge or the test fuel charge charged into the space through the outer side.

Further, the charging equipment for testing (20) comprises a moving panel part (28) disposed at the lower part of the charging guide chute (27) and moving forward and backward; And

And a panel moving unit (29) for moving the moving panel unit (28).

The panel moving unit 29 includes a hydraulic cylinder having a piston rod connected to the moving panel unit 28. The panel moving unit 29 may be modified as various examples capable of moving the moving panel unit 28 forward and backward It is possible.

The moving panel portion 28 is disposed at the lower portion of the loading guide chute member 27 and moves forward and backward between the lower end of the loading guide chute member 27 and the inner side surface of the openable body portion 12 do. The moving panel unit 28 controls the loading distribution of the test material charge or the test fuel charge by adjusting the interval between the lower end of the charge water guide chute member 27 and the openable body part 12. And controls the charging distribution of the test material charge or the test fuel charge which is guided through the charge guide chute member 27 and charged into the test body body member 10.

For example, as the moving panel portion 28 is closer to the lower end of the charging guide shute member 27, the test material charge or the test fuel charge is charged into the central portion of the test furnace body member 10 will be. The moving panel unit 28 can be implemented by variously changing the test conditions by controlling the charge distribution of the test material charge or the test fuel charge charged into the test body body member 10.

The blast furnace operation test apparatus according to the present invention includes a test furnace body member 10 and a pressure regulating pipe 22 connected to the charging hopper members 22 and 23 for communicating the interior of the charging hopper members 22 and 23 Member (80).

The pressure control pipe member 80 is configured to control the pressure in the space portion and the pressure of the inner pressure of the charging hopper members 22 and 23 when the test material charge and the test fuel charge are continuously charged into the space portion Thereby preventing the occurrence of an abnormality in the charging water drop due to the water supply.

The pressure control pipe member 80 includes a first pressure control pipe 81 for connecting the open end portion 12 and the raw material storage hopper member 22;

And a second pressure regulating pipe (82) connecting the fuel cell storage hopper member (23) with the open end (12).

Further, the pressure control pipe member (80)

A first pressure gauge 83 for measuring the internal pressure of the raw material storage hopper member 22;

A second pressure gauge 84 for measuring the internal pressure of the fuel storage hopper member 23;

A first pressure control valve 85 provided in the first pressure control pipe 81 for opening and closing the channel;

A second pressure control valve 86 provided in the second pressure control pipe 82 for opening and closing the channel; .

The first pressure gauge 83, the second pressure gauge 84, the first pressure control valve 85 and the second pressure control valve 86 are connected to the furnace pressure control unit 12e. The furnace pressure control section 12e controls the operation of the first pressure control valve 85 and the second pressure control valve 86 in accordance with the pressure measured by the first pressure gauge 83 and the second pressure gauge 84 .

Further, the blast furnace operation test apparatus according to the present invention further includes a pressure sensor member 90 connected to the furnace pressure control unit 12e and measuring the pressure in the space portion. It is preferable that the pressure sensor member 90 includes a first sensor 91 for measuring the pressure in the blast furnace body 11 and a second sensor 92 for measuring the pressure in the furnace body 12 desirable.

The pressure regulating pipe member 80 is connected to the first pressure regulating pipe 81 and the second pressure regulating pipe 82 in accordance with the internal pressure of each of the raw material storing hopper member 22 and the fuel storing hopper member 23, The opening and closing amount of the second pressure control pipe 82 is controlled so that the charge is smoothly charged into the space and the charged charge is smoothly and normally lowered.

3 and 4, the blast furnace body 11 will be described in more detail as follows.

The blast furnace body part 11 is provided with a transparent part 11a on either the front side or the rear side so that the inside can be recognized. The upper part of the blast furnace body 11 is formed with a blind hole for charging the test material charge and the test fuel charge. It is preferable that the transparent portion 11a forms a front surface or a front surface of the rear surface so that the entire interior of the blast furnace body 11 can be easily confirmed.

The blast furnace body portion 11 has a shape in which the vertical cross-section between the front surface and the rear surface has a shape corresponding to the vertical cross-section at the center of the blast furnace to be actually simulated, thereby accurately confirming the behavior of the charge at the center portion of the blast furnace.

The blast furnace body 11 is manufactured by reducing the blast furnace to be a target of simulation to a certain ratio, and is manufactured by reducing the blast furnace to a scale of 1/20 to 1/50.

The raw material charge for test is filled into the space portion in place of iron ore or sintered ores, which are raw materials used in actual blast furnace operation, and is a pellet made of paraffin. The pellet body has a particle diameter reduced to a ratio suitable for the simulation test of the blast furnace at the particle diameter of the iron ore or sintered ore charged in the actual blast furnace. It is noted that this is set in consideration of the shape difference and the scale ratio of the blast furnace body 10 to be actually simulated and the test furnace body member 10.

In addition, the above-mentioned raw material charge for test is an example of using coke, which is a raw material used in actual blast furnace operation, and the coke used as the raw material charge for the test is used for simulating blast furnace operation at the particle diameter of coke charged into actual blast furnace An example is one having a reduced diameter at an appropriate ratio. It is noted that this is set in consideration of the shape difference and the scale ratio of the blast furnace body 10 to be actually simulated and the test furnace body member 10.

The thermal insulation material 10a is inserted into both sides of the test body body 10 and the other side of the front and rear surfaces to minimize heat transfer to the outside from the space to the outside, It is preferable that the temperature can be kept constant at an appropriate temperature, that is, the test condition temperature, and the temperature in the space portion is influenced by the external temperature to prevent the test conditions from being deformed.

The blast furnace operation test apparatus according to the present invention may further include a transparent cover member 60 coupled to the test body body member 10 on either side of the front and back surfaces of the blast furnace body portion 11 . The transparent cover member 60 covers the transparent portion 11a formed on one of the front surface and the back surface of the blast furnace body portion 11. The transparent cover member 60 minimizes heat transfer to the outside through the transparent portion 11a to the outside so that the temperature in the space portion can be maintained at an appropriate temperature, And the temperature in the space portion is influenced by the external temperature to prevent the test conditions from being deformed.

In addition, the transparent portion 11a is provided with a heat-transfer coil 10b to prevent the molten test material from solidifying on the inner surface of the transparent portion 11a, ≪ / RTI > That is, the heat-transfer coil 10b receives heat from the electric power source and heats the transparent portion 11a to prevent paraffin from adhering to the inner surface of the transparent portion 11a. Therefore, the tester can always accurately check the situation in the space portion through the transparent portion 11a.

Referring again to FIG. 1, a heating air supplier 30 for supplying heated air into the space portion is connected to the lower portion of the test furnace body member 10. The heating air supplier 30 is connected to both sides of the test body body member 10 to supply the heated air from the opposite sides of the test body body member 10 into the space portion uniformly. The heating air supplier (30) includes an air supply unit (31) connected to the test body body member (10) for supplying air into the test body body member (10)

An air supply pipe portion 32 connecting the air supply portion 31 and the test body body member 10 to supply air into the test body body member 10;

A heating unit 33 mounted on the air supply pipe 32 and heating the air supplied into the space;

A temperature sensor 34 mounted on the air supply pipe 32 for measuring the temperature of air supplied into the space;

And a heating control unit 35 connected to the heating unit 33 and the temperature sensor unit 34 to control the operation of the heating unit 33. The air supply unit 31 is an air compressor for compressing the air, and the air is compressed and supplied into the space portion by a pressure difference. The air supply unit 31 may be a blower (not shown) that sucks outside air into the air supply pipe 32 and supplies the air into the space. The heated air supplier 30 supplies air heated to 150 ° C to 200 ° C into the space, and supplies heated air at a temperature capable of melting the raw material charge for test.

The heating air supplier 30 further includes a control valve 36 mounted on the air supply pipe 32 and connected to the heating control unit 35 to control the opening and closing amount of the air supply pipe 32 And controls the amount of heated air supplied to the interior of the test furnace body member (10).

The heating air supplier 30 controls the operation of the heating unit 33 by the heating control unit 35 to supply air into the space by heating the air to the test condition temperature. The heating air supplied into the space part melts and liquefies the pellet body made of paraffin, that is, the raw material charge for test loaded into the space part. The pellet body is melted by the heated air supplied into the space portion through the heated air supplier 30 so that iron ore or sintered ores, which are raw materials used in actual blast furnace operation, are mixed with hot air and coke supplied from the lower part of the blast furnace, It melts through the reaction and simulates it.

The air supply pipe portion 32 is branched into two pipes, and two branched pipes are connected to both sides of the test furnace body member 10, respectively, so that heated air .

The side surface of the test blast furnace body member (10) includes a powder supply unit (70) for supplying powder into the space portion. The powder feeder (70) supplies powder of the fuel charge for test so that the behavior of powder in the furnace can be confirmed. The powder feeder (70) includes a powder feed pipe member (71) connected to a side surface of the test body body member (10);

A first powder control valve (72) mounted on the powder supply pipe member (71) for opening and closing a channel of the powder supply pipe member (71);

A powder storage member (73) for supplying powder into the powder supply pipe member (71); And

And a compressor (75) for supplying compressed air into the powder supply pipe member (71) to discharge the powder of the powder supply pipe member (71) into the space.

The powder storage member 73 includes a first powder storage portion 73a and a second powder storage portion 73b connected to the powder supply pipe member 71 and includes a first powder storage portion 73a and a second powder storage portion 73b. And the powder stored in the powder storage portion 73b can be alternately supplied to the powder supply pipe member 71. [ This is because when the powder of the first powder storage portion 73a is used up, the second powder storage portion 73b is used while filling the powder in the first powder storage portion 73a, and conversely, The powder of the first powder storage portion 73a is used when the powder of the second powder storage portion 73b is used up.

The powder supply pipe member 71 is connected to a portion corresponding to the lower portion of the shaft in the blast furnace body member 10 to supply the powder into the space portion so as to easily confirm powder behavior in the furnace.

The powder feeder 70 includes a powder input pipe member 76 connecting the powder feed pipe member 71 and the heat feed pipe portion 32 to inject the powder into the heat supply pipe portion 32; And

And a second powder control valve 77 mounted on the powder feed pipe member 76 for opening and closing the channel of the powder feed pipe member 76.

The powder feeder 70 feeds the powder into the heating supply pipe portion 32 through the powder feed pipe member 76 and discharges the powder into the space portion together with the heated air through the heating supply pipe portion 32 .

The powder feeder 70 may selectively supply the powder into the space portion through the powder feed pipe member 71 and the heating feed pipe portion 32 and may supply the powder to the powder feed pipe member 71 and the heating supply pipe portion 32) into the space portion at the same time.

The supply of the powder controls the operation of the first powder control valve 72 and the second powder control valve 77 to control the amount of opening and closing of the powder feed pipe member 71 and the powder feed pipe member 76 . The powder supply pipe member 71 is branched into two pipes, and two branched pipes are connected to both sides of the test furnace body member 10, respectively, and powder is supplied to both sides of the test furnace body member 10 Supply.

The powder feeder 70 is capable of quantitatively dispensing powder, enabling quantitative evaluation of the effects of in-furnace dust behavior depending on the amount of actual pulverized coal injected, and enables localized accumulation control by radial position to simulate aging anomalies I will.

The blast furnace operation test apparatus according to the present invention is connected to a central portion of either one of a front surface and a rear surface of the test blast furnace body member 10 to load a test fuel charge into the space, And a charging water supplier 40. The fuel charging water supply device 40 is connected to the back surface of the test body body member 10 as an example. The fuel charge water supply device 40 includes a storage unit 41 for storing the fuel charge 10 for test and a fuel supply unit 40 for connecting the storage unit 41 and the test body body member 10, A supply pipe portion (42) for supplying a test fuel charge; And a fuel feeder 43 for feeding the test fuel charge in the supply pipe 42 into the space portion. The storage unit 41 includes a main storage hopper 41a for storing a test fuel charge 10 and a fuel supply unit 40 connected to the main storage hopper 41, And a hopper 41b.

The blast furnace operation test apparatus according to the present invention may include an artificial core member 40a disposed at the center of the bottom surface in the space portion of the test body body member 10 for testing. The artificial core member is made of a urethane material. For example, the artificial core member has heat resistance to 150 ° C to 200 ° C. It has heat resistance against the temperature of the heated air introduced through the heated air supplier 30, It is prevented from being deformed by air. Preferably, the artificial core member is manufactured in various sizes and shapes and is replaceable so that the test conditions can be changed.

The blast furnace operation test apparatus according to the present invention further includes a charge discharge device 50 mounted on a lower portion of the test blast furnace body member 10 to discharge the charge charged into the test furnace body member 10.

In addition, the test blast furnace body member 10 is provided with charging water discharge ports on both sides of the artificial core member 40 on the lower surface thereof. In addition, the charge discharging device 50 discharges the charge discharged from the charging port, that is, the test material charge or the test fuel charge, to the outside of the test body body member 10.

5, the supply pipe portion 42 is connected to a charging hole formed on the back surface of the test blast furnace body member 10, and the fuel transfer portion 43 is rotatably installed in the supply pipe portion 42 A conveying screw portion 43a to be disposed;

And a motor unit 43b for rotating the feed screw unit 43a.

The fuel feed part 43 is charged into the space part by rotation of the feed screw part 43a after being discharged from the feed hopper 41b and supplied into the fuel supply pipe part 42, An artificial core member 40a is formed at the center of the lower surface of the body member 10 of the blast furnace.

Referring to FIG. 6, the charge discharger 50 includes a charge storage 51a for storing the charge discharged to the charge discharge port, and the charge storage 51a A discharge body member 51 in which a charge water discharge passage 51b for connecting the discharge passage 51a is formed;

A rotatable shaft member 51c disposed horizontally and rotatable on the charge discharge path 51b;

A discharge guide wire member 51d spirally wound around the rotating shaft member 51c;

And a rotating motor 51e for rotating the rotating shaft member 51c.

The charged-water discharging device 50 further includes a charging water heater 51f provided inside the discharging body member 51 so that when the charging object is moved through the charging-discharging passage 51b Thereby preventing the charging water discharge path 51b from becoming clogged.

The charge discharging device 50 rotates the rotating shaft member 51c and moves the charging object by the helical guiding wire member 51d so that the charging object is not damaged by being pinched during discharging, So that it can be smoothly discharged.

Meanwhile, in the blast furnace operation test apparatus according to the present invention, a pellet as a raw material charge for test and a coke as a fuel charge for test are charged alternately into the interior of the test blast furnace body member 10 by the charging apparatus 20 for testing, And heating air is supplied to the inside of the test furnace body member (10) by the heated air supplier (30) to simulate the blast furnace operation.

At this time, a phase change of the charge (liquid in solid) is generated at the center of the test body body member 10, and a soft welded joint in which all three phases of the rising gas coexist can be realized. The tester can confirm the inside of the operation body with the test bladder through the transparent portion 11a.

The present invention can similarly confirm the behavior of solids, liquids and gases in actual blast furnace operation by similarly reproducing softened welded zones in actual blast furnaces.

The present invention can also observe in-furnace gas generation behavior and similarly reproduce the pressure loss transition simulation in the height direction of the blast furnace.

The present invention can similarly reproduce the actual blast furnace operation, accurately test the blast furnace operation under various conditions, and provide reliable test data to solve problems in actual blast furnace operation.

It will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention.

10: test furnace body member 11: blast furnace body portion
12: Lid body 20: Equipment for testing
30: Heating air supply 40: Artificial core member
50: Charge discharge device 60: Transparent cover member
80: pressure control pipe member 90: pressure sensor member

Claims (5)

And a charging hopper member for storing the test fuel feed and the test feed stock, and a charging hopper member for discharging the test fuel charge downward;
A test furnace body member having a hollow space for loading the test raw material charge discharged from the charging hopper member and a space for loading the test fuel charge therein and having a transparent portion on either the front surface or the rear surface for inspecting the inside thereof;
A heating air supplier connected to a lower side of the test body body member for supplying heated air into the test body body member;
A gas discharge pipe member provided on an upper side of the test blast furnace body member;
A control valve for controlling an amount of gas discharged to the gas discharge pipe member; And
And an artificial core member disposed at a lower portion of the blast furnace body member. The method according to claim 1,
Further comprising a furnace pressure sensor unit provided on the gas discharge pipe member for measuring a furnace pressure of the test furnace body member. The method according to claim 1,
Further comprising a blower provided at a discharge port side of the gas discharge pipe member for blowing air out of the test furnace body member to the outside. The method according to claim 1,
Further comprising a pressure control pipe member connected to the test blast furnace body member and the charging hopper member and communicating with the space portion and the inside of the charging hopper member. The method of claim 4,
The test furnace body member has a furnace body portion connected to the charging hopper member at an upper portion thereof,
The pressure regulating tube member includes:
A pressure control pipe connecting the charging hopper member and the open end body portion;
A pressure gauge for measuring the internal pressure of the raw material storage hopper member;
And a pressure control valve provided in the pressure control pipe to open and close the conduit.

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