CN115837944A - Gas monitoring device for disaster prevention and sealing of power plant flue gas injected into goaf - Google Patents

Abstract

The invention belongs to the technical field of goaf gas monitoring, provides a gas monitoring device for preventing disaster and sealing in a power plant flue gas injection goaf, and solves the problem that gas monitoring is interrupted due to the fact that a gas monitoring vehicle is prone to overturning due to the complex environment of the goaf. The image acquisition module is used for providing real-time monitoring pictures, and transmit to control terminal through wireless communication module, control terminal long-range control command that sends, wireless communication module transmits received control command to host system, host system control track structure of traveling with prevent the motor action in the structure of empting, make track structure of traveling steadily pass through the barrier, gas monitoring module is used for detecting gas concentration data, instant data transmits to control terminal through wireless communication module. When the track driving structure crosses the barrier, the main control module controls the turning rod at the third anti-inclination rod to be supported on the ground, and the auxiliary track driving structure passes through the barrier.

Description

A gas monitoring device for power plant flue gas injection into goaf for disaster prevention and storage

technical field

The invention belongs to the technical field of goaf gas monitoring, and in particular relates to a gas monitoring device for injecting power plant flue gas into the goaf for disaster prevention and sealing.

Background technique

Coal-fired thermal power plants will produce a lot of flue gas, the main components are carbon dioxide and nitrogen, and the oxygen content is low. The flue gas of the power plant is directly injected into the underground goaf through the gas pipeline, which can dilute the oxygen content in the underground air; In addition, because the adsorption capacity of coal for oxygen is weaker than that for carbon dioxide, the contact between residual coal and oxygen can be reduced, and the purpose of inerting the underground air can be achieved, so as to effectively prevent and control fires caused by spontaneous combustion of coal.

A large amount of gas injection in the shallow part of the goaf can effectively inhibit the self-heating of the residual coal; gas injection in the deep part of the goaf can improve the inertization level of the deep residual coal, and is also conducive to the storage of harmful gases such as carbon dioxide in the flue gas by the residual coal . Flue gas is industrial waste. Compared with the traditional nitrogen production technology, the cost is lower, and there is no need for gas preparation. The cost is relatively low, which can save energy waste caused by nitrogen production. Underground flue gas injection to prevent coal spontaneous combustion is a project that saves energy, realizes safe production in coal mines, and reduces air pollution. This technology can not only inert coal mine goafs to prevent coal spontaneous combustion, but also reduce waste gas emissions and protect the ecological environment .

The fire prevention and extinguishing technology of power plant flue gas injected into the goaf is still in the project research stage in my country. Due to the complex environment of the gob, gas monitoring vehicles are prone to overturning, resulting in the interruption of gas monitoring.

Contents of the invention

In order to solve the problem that the gas monitoring vehicle is prone to overturning due to the complex environment of the goaf, which causes the interruption of gas monitoring, the present invention provides a gas monitoring device for injecting power plant flue gas into the goaf for disaster prevention and sealing. The image acquisition module provides real-time Monitor the screen and transmit it to the control terminal through the wireless communication module, the control terminal sends out control commands remotely, the wireless communication module transmits the received control commands to the main control module, and the main control module controls the motor action in the crawler driving structure and the anti-dumping structure , so that the crawler structure passes through obstacles smoothly and avoids the overturning of the vehicle.

The present invention adopts the following technical solutions to realize: a gas monitoring device for injecting power plant flue gas into goaf for disaster prevention and sealing, including a crawler driving structure, a main control module, a gas monitoring module, an image acquisition module, a wireless communication module, a storage module, Power supply module, anti-dump structure and control terminal; anti-dump structure includes first anti-roll bar, second anti-roll bar, third anti-roll bar, hollow servo motor, servo reduction motor, first rotation servo motor and second rotation servo The motor and the chassis are connected between the two crawlers of the crawler structure. The hollow servo motor is arranged on the chassis and its drive shaft is perpendicular to the track. The first anti-roll bar is connected to the drive shaft of the hollow servo motor through a keyway. The second anti-roll The axis of the bar coincides with the axis of the first anti-roll bar, and the second anti-roll bar rotates around the axis of the first anti-roll bar under the action of the servo reduction motor. One end of the rod, the transmission shaft of the first rotary servo motor is perpendicular to the second anti-roll bar, the third anti-roll bar is connected to the transmission shaft of the first rotary servo motor through a keyway, and the third anti-roll bar is far away from the second anti-roll bar One end of one end has a crutch that plays a supporting role, the second rotary servo motor is fixedly connected to the crutch, and the gas monitoring module is connected to the transmission shaft of the second rotary servo motor through a keyway; the main control module, the wireless communication module, the storage module, The power supply modules are all set on the chassis, and the image acquisition module is used to provide real-time monitoring images, which are transmitted to the control terminal through the wireless communication module. The control terminal sends out control commands remotely, and the wireless communication module transmits the received control commands to the main control module. , the main control module controls the motor action in the crawler driving structure and the anti-dumping structure, so that the crawler driving structure can pass obstacles smoothly. The gas monitoring module is used to detect the gas concentration data and transmit it to the storage module. The storage module transmits the real-time data through wireless communication. The module is transmitted to the control terminal, and the power supply module is used to supply power to the gas monitoring device.

Preferably, the gas monitoring module includes a gas sensing probe and a gas sensor. The gas sensor includes a methane sensor, an oxygen sensor, a carbon monoxide sensor, a carbon dioxide sensor and a sulfur dioxide sensor. The gas sensing probe is provided with a dust filter for preventing coal dust from entering.

Preferably, the image acquisition module includes a first camera arranged at the gas sensing probe and an elevating camera assembly arranged on the chassis. The elevating camera assembly includes a DC motor, a screw mandrel, a guide rail, a sliding table and a second camera, and the DC motor drives the wire The rod rotates, and then controls the sliding table connected on the guide rail to move up and down, and the second camera is fixedly connected on the sliding table and is located at the front outer wall of the chassis.

Preferably, the chassis has a notch for avoiding the first anti-roll bar, and the key at the lower end of the first anti-roll bar for connecting with the hollow servo motor is located in the notch, and the hollow servo motor changes the relative position of the first anti-roll bar and the chassis , can realize the double-sided walking of the crawler structure.

Preferably, the control terminal is provided with an early warning module, and when the control terminal detects that the gas concentration exceeds the threshold, it sends an alarm command to the early warning module, and the early warning module sends out an alarm.

Preferably, the servo geared motor is a worm gear reducer, the housing of the servo geared motor is fixedly connected to the first anti-roll bar, the worm of the servo geared motor is connected to the drive shaft of the servo geared motor, and the worm gear of the servo geared motor is connected to the second Anti-roll bar keyed connection.

Preferably, when the crawler traveling structure crosses an obstacle, the main control module controls the motor action in the crawler traveling structure and the anti-dumping structure, so that the turning lever is supported on the ground, and the position of the gas monitoring module is adjusted so that it is located on one side of the turning lever above.

Preferably, one side of the crawler structure is located on the obstacle, and the other side is located on the ground. When the two form a height difference, the second anti-roll bar rotates under the action of the servo deceleration motor, so that the third anti-roll bar is positioned at a low level. On one side of the point, the first rotating servo motor drives the third anti-roll bar to rotate, so that the turning bar is supported on the ground, so that the track driving structure can pass obstacles on the side stably.

Preferably, one end of the crawler structure is located on the obstacle, and the other end is located on the ground. When the two form a height difference, the second anti-roll bar rotates under the action of the servo reduction motor, so that the third anti-roll bar is located on the side of the low point , the first rotating servo motor drives the third anti-roll bar to rotate, so that the turning bar is supported on the ground, so that the crawler structure can pass the obstacle smoothly and frontally.

Compared with prior art, the beneficial effect of the present invention is:

The image acquisition module provides real-time monitoring images, and transmits them to the control terminal through the wireless communication module. The control terminal sends control commands remotely, and the wireless communication module transmits the received control commands to the main control module, which controls the crawler structure and anti-dumping The motor action in the structure makes the crawler structure pass through obstacles smoothly and avoids the overturning of the vehicle.

In this device, when the crawler traveling structure crosses an obstacle, the main control module controls the motor action in the crawler traveling structure and the anti-dumping structure, so that the turning rod at the third anti-roll bar is supported on the ground, and the auxiliary crawler traveling structure passes through the obstacle.

When the crawler running structure rolls over in the device, the crutch at the third anti-roll bar is supported on the ground and continues to move under the drive of the motor until the gas monitoring device is righted; the crawler running structure can realize double-sided walking.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the three-dimensional structure schematic diagram of the present embodiment;

Fig. 2 is a schematic side view of the present embodiment;

Fig. 3 is the top view of present embodiment;

Fig. 4 is a schematic diagram of the present embodiment crossing obstacles in front;

Fig. 5 is a schematic diagram of passing through obstacles on the side of the present embodiment;

Figure 6 is a schematic front view of the present embodiment;

Fig. 7 is a schematic cross-sectional view at A-A in Fig. 2;

Fig. 8 is a schematic cross-sectional view at B-B in Fig. 2;

Fig. 9 is a schematic cross-sectional view at E-E in Fig. 2;

Fig. 10 is a schematic cross-sectional view at C-C in Fig. 3;

Fig. 11 is a schematic cross-sectional view at D-D in Fig. 3;

Fig. 12 is a schematic diagram of the structure of the servo gear motor.

In the figure: 1-crawler driving structure; 2-main control module; 3-gas monitoring module; 3.1-gas sensing probe; 3.2-methane sensor; 3.3-oxygen sensor; 3.4-carbon monoxide sensor; 3.5-carbon dioxide sensor; 3.6-sulfur dioxide Sensor; 3.7-dust filter; 4-image acquisition module; 4.1-first camera; 4.2-lift camera assembly; 4.21-DC motor; 4.22-screw; ;5-wireless communication module; 6-storage module; 7-power supply module; 8-anti-dumping structure; 8.1-first anti-roll bar; 8.2-second anti-roll bar; Rod; 8.4-hollow servo motor; 8.5-servo reduction motor; 8.6-first rotation servo motor; 8.7-second rotation servo motor; 9-chassis; 9.1-notch; 9.2-charging port; 10-control terminal; 11- Early warning module; 12-obstacle; 13-track; 14-track wheel; 15-dust cover.

Detailed ways

The technical solutions in the embodiments of the present invention are clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other implementations obtained by persons of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

It should be noted that the structures, proportions, sizes, etc. shown in the drawings of this specification are only used to match the content disclosed in the specification, for those who are familiar with this technology to understand and read, and are not used to limit the conditions for the implementation of the present invention , so it has no technical substantive meaning, and any modification of structure, change of proportional relationship or adjustment of size shall fall within the scope of the invention disclosed Within the scope covered by the technical content, it should be noted that in this specification, relative terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply There is no real relationship or order between these entities.

The present invention provides an embodiment:

As shown in Figures 1 to 12, a gas monitoring device for injecting power plant flue gas into a goaf for disaster prevention and storage, including a crawler driving structure 1, a main control module 2, a gas monitoring module 3, an image acquisition module 4, and a wireless communication module 5. Storage module 6, power supply module 7, anti-dump structure 8 and control terminal 10; anti-dump structure 8 includes first anti-roll bar 8.1, second anti-roll bar 8.2, third anti-roll bar 8.3, hollow servo motor 8.4, Servo deceleration motor 8.5, first rotation servo motor 8.6 and second rotation servo motor 8.7, chassis 9 is connected between two crawlers 13 of crawler belt driving structure 1, hollow servo motor 8.4 is arranged on chassis 9 and its transmission shaft and crawler belt 13 Vertical, the first anti-roll bar 8.1 is connected to the transmission shaft of the hollow servo motor 8.4 through a keyway, the axis of the second anti-roll bar 8.2 and the first anti-roll bar 8.1 coincide, and the role of the second anti-roll bar 8.2 on the servo reduction motor 8.5 Rotate around the axis of the first anti-roll bar 8.1, the first rotary servo motor 8.6 is fixedly connected to the end of the second anti-roll bar 8.2 away from the first anti-roll bar 8.1, the drive shaft of the first rotary servo motor 8.6 is connected to the second anti-roll bar 8.6 The 8.2 anti-roll bar is vertical, the third anti-roll bar 8.3 is connected to the transmission shaft of the first rotary servo motor 8.6 through a keyway, and the end of the third anti-roll bar 8.3 far away from the second anti-roll bar 8.2 has a support lever 8.31, The second rotary servo motor 8.7 is fixedly connected to the turning rod 8.31, and the gas monitoring module 3 is connected to the transmission shaft of the second rotary servo motor 8.7 through a keyway;

The main control module 2, the wireless communication module 5, the storage module 6, and the power supply module 7 are all arranged on the chassis 9, wherein the image acquisition module 4 is used to provide a real-time monitoring picture, and is transmitted to the control terminal 10 through the wireless communication module 5, and the control terminal 10 Remotely issue control commands, the wireless communication module 5 transmits the received control commands to the main control module 2, and the main control module 2 controls the motor action in the crawler driving structure 1 and the anti-dumping structure 8, so that the crawler driving structure 1 passes through obstacles smoothly 12, the gas monitoring module 3 is used to detect the gas concentration data, and transmits to the storage module 6, the storage module 6 transmits the real-time data to the control terminal 10 through the wireless communication module 5, and the power supply module 7 is used to supply power to the gas monitoring device, The chassis 9 is provided with a charging port 9.2 of the power supply module 7, and the control terminal 10 can remotely check the remaining power of the power supply module 7.

The gas monitoring module 3 includes a gas sensing probe 3.1 and a gas sensor. The gas sensor includes a methane sensor 3.2, an oxygen sensor 3.3, a carbon monoxide sensor 3.4, a carbon dioxide sensor 3.5 and a sulfur dioxide sensor 3.6. The gas sensing probe 3.1 is provided with dust for preventing coal dust from entering The filter 3.7 and the gas sensing probe 3.1 can reach a specific location to collect gas, and then feed back to the gas sensor to monitor the gas concentration in a wide range; the control terminal 10 is provided with an early warning module 11, and the control terminal 10 detects that the gas concentration exceeds the threshold. , sending an alarm command to the early warning module 11, and the early warning module 11 issues an alarm.

The image acquisition module 4 includes a first camera 4.1 arranged at the gas sensing probe 3.1 and an elevating camera assembly 4.2 arranged on the chassis 9. The elevating camera assembly 4.2 includes a DC motor 4.21, a screw mandrel 4.22, a guide rail 4.23, a slide table 4.24 and the first camera assembly 4.2. The second camera 4.25, the DC motor 4.21 drives the screw rod 4.22 to rotate, and then controls the slide table 4.24 connected on the guide rail 4.23 to move up and down, and the second camera 4.25 is fixedly connected to the slide table 4.24 and is located at the front outer wall of the chassis 9, which is convenient for operators Understand the internal situation of the gob and control the crawler structure 1 .

The servo gear motor 8.5 is a worm gear reducer, the housing of the servo gear motor 8.5 is fixedly connected to the first anti-roll bar 8.1, the worm of the servo gear motor 8.5 is connected to the transmission shaft of the servo gear motor 8.5, and the worm gear of the servo gear motor 8.5 Key connection with the second anti-roll bar 8.2.

There is a notch 9.1 on the chassis 9 for avoiding the first anti-roll bar 8.1, the key at the lower end of the first anti-roll bar 8.1 for connecting with the hollow servo motor 8.4 is located in the notch 9.1, and the hollow servo motor 8.4 changes the first anti-roll bar 8.1 The relative position with the chassis 9 can realize the double-sided walking of the crawler driving structure 1, which is not afraid of overturning and can overcome the complex terrain of the goaf.

The motors of the crawler traveling structure 1 and the anti-dumping structure 8 are all explosion-proof motors, and the outer side of the crawler traveling structure 1 is provided with a dust cover 15 for preventing dust from entering, so as to overcome the complex environment of the goaf to work; the driving motor of the crawler traveling structure 1 Drive the crawler wheel 14 to rotate, and control the different speeds and directions of the motors on both sides through the main control module 2 to realize the steering and movement of the crawler driving structure 1 .

When the crawler traveling structure 1 crosses the obstacle 12, the motor action in the crawler traveling structure 1 and the anti-dumping structure 8 is controlled by the main control module 2, so that the turning rod 8.31 is supported on the ground, and the position of the gas monitoring module 3 is adjusted so that it is at the corner. One side of rod 8.31 above.

Specifically: one side of the crawler belt 13 of the crawler driving structure 1 is located on the obstacle 12, and the other side of the crawler belt 13 is located on the ground. Three anti-roll bars 8.3 are positioned at the low point side, and the first rotary servo motor 8.6 drives the third anti-roll bar 8.3 to rotate, and the turning bar 8.31 is supported on the ground, so that the crawler belt driving structure 1 passes through the obstacle 12 on a stable side.

One end of the crawler structure 1 is located on the obstacle 12, and the other end is located on the ground. When the height difference between the two is formed, the second anti-roll bar 8.2 rotates under the action of the servo reduction motor 8.5, so that the third anti-roll bar 8.3 is located at the lowest point On one side, the first rotating servo motor 8.6 drives the third anti-roll bar 8.3 to rotate, so that the turning bar 8.31 is supported on the ground, so that the crawler structure 1 passes through the obstacle 12 in a smooth front.

When the track running structure 1 rolls over in the device, the turning bar 8.31 at the third anti-roll bar 8.3 is supported on the ground and continues to move under the drive of the motor until the track running structure 1 is righted.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (9)

1. The utility model provides a gas monitoring devices that power plant's flue gas pours into goaf disaster prevention and seals up deposit which characterized in that: the device comprises a track running structure (1), a main control module (2), a gas monitoring module (3), an image acquisition module (4), a wireless communication module (5), a storage module (6), a power supply module (7), an anti-toppling structure (8) and a control terminal (10);

the anti-toppling structure (8) comprises a first anti-toppling rod (8.1), a second anti-toppling rod (8.2), a third anti-toppling rod (8.3), a hollow servo motor (8.4), a servo speed-reducing motor (8.5), a first rotary servo motor (8.6) and a second rotary servo motor (8.7), a chassis (9) is connected between two tracks of the track running structure (1), a hollow servo motor (8.4) is arranged on the chassis (9) and a transmission shaft of the hollow servo motor (8.4) is vertical to the tracks, a first anti-tilting rod (8.1) is connected to the transmission shaft of the hollow servo motor (8.4) through a key slot, a second anti-tilting rod (8.2) and a first anti-tilting rod (8.1) are overlapped in axis, a second anti-tilting rod (8.2) rotates around the axis of the first anti-tilting rod (8.1) under the action of a servo speed reduction motor (8.5), a first rotary servo motor (8.6) is connected to one end, far away from the first anti-tilting rod (8.1), of the second anti-tilting rod (8.2), the transmission shaft of the first rotary servo motor (8.6) is vertical to the second anti-tilting rod (8.2), a third anti-tilting rod (8.3) is connected to the transmission shaft of the first rotary servo motor (8.6) through a key slot, a third anti-tilting rod (8.3) is connected to one end, which is far away from the second anti-tilting rod (8.2), and a second anti-tilting rod (8.3) is connected to a rotary servo motor module (7.3) which has a function of monitoring module which is connected to the second anti-tilting rod (8.3) and has a function of a gas-tilting rod (8.3);

host system (2), wireless communication module (5), storage module (6), power module (7) all set up on chassis (9), wherein image acquisition module (4) are used for providing the real time monitoring picture, and transmit to control terminal (10) through wireless communication module (5), control terminal (10) long-range control command that sends, wireless communication module (5) transmit received control command to host system (2), motor action in host system (2) control track structure (1) of traveling and prevent empting structure (8), make track structure (1) of traveling steadily pass through the barrier, gas monitoring module (3) are used for detecting gas concentration data, and transmit to storage module (6), storage module (6) transmit instant data to control terminal (10) through wireless communication module (5), power module (7) are used for supplying power for this gas monitoring device.

2. The gas monitoring device for disaster prevention and sealing of the goaf injected with the flue gas of the power plant according to claim 1, wherein: gaseous monitoring module (3) including gaseous sense probe (3.1) and gas sensor, gas sensor includes methane sensor (3.2), oxygen sensor (3.3), carbon monoxide sensor (3.4), carbon dioxide sensor (3.5) and sulfur dioxide sensor (3.6), is provided with dust filter (3.7) that are used for preventing the coal dust entering on gaseous sense probe (3.1).

3. The gas monitoring device for disaster prevention and sealing of the goaf injected with the flue gas of the power plant according to claim 2, wherein: image acquisition module (4) including setting up first camera (4.1) and the lift subassembly of making a video recording (4.2) of setting on chassis (9) of feeling probe (3.1) department at gas, lift subassembly of making a video recording (4.2) includes direct current motor (4.21), lead screw (4.22), guide rail (4.23), slip table (4.24) and second camera (4.25), direct current motor (4.21) drive lead screw (4.22) and rotate, and then sliding table (4.24) of control connection on guide rail (4.23) reciprocate, second camera (4.25) link firmly on slip table (4.24) and are located the place ahead outer wall department of chassis (9).

4. The gas monitoring device for disaster prevention and sealing of the goaf injected with the flue gas of the power plant according to any one of claims 1 to 3, wherein: the chassis (9) is provided with a notch (9.1) for avoiding the first anti-roll bar (8.1), the lower end of the first anti-roll bar (8.1) is located in the notch (9.1) through a key connected with the hollow servo motor (8.4), and the hollow servo motor (8.4) changes the relative position of the first anti-roll bar (8.1) and the chassis (9), so that double-sided walking of the crawler traveling structure (1) can be realized.

5. The gas monitoring device for disaster prevention and sealing of the goaf injected with the flue gas of the power plant according to claim 1, wherein: the gas concentration monitoring system is characterized in that an early warning module (11) is arranged at the control terminal (10), when the control terminal (10) detects that the gas concentration exceeds a threshold value, an alarm instruction is sent to the early warning module (11), and the early warning module (11) gives an alarm.

6. The gas monitoring device for disaster prevention and sealing of the goaf injected with the flue gas of the power plant according to claim 1, wherein: the servo speed reducing motor (8.5) is a worm gear and worm speed reducer, a shell of the servo speed reducing motor (8.5) is fixedly connected to the first anti-roll rod (8.1), a worm of the servo speed reducing motor (8.5) is connected with a transmission shaft of the servo speed reducing motor (8.5), and a worm gear of the servo speed reducing motor (8.5) is connected with the second anti-roll rod (8.2) in a key mode.

7. The gas monitoring device for disaster prevention and sealing of the goaf injected with the flue gas of the power plant according to claim 1, wherein: when the crawler traveling structure (1) crosses an obstacle, the main control module (2) controls the motors in the crawler traveling structure (1) and the anti-toppling structure (8) to act, so that the turning rod (8.31) is supported on the ground, and the position of the gas monitoring module (3) is adjusted to be located above one side of the turning rod (8.31).

8. The gas monitoring device for disaster prevention and sealing of the goaf injected with the flue gas of the power plant according to claim 7, wherein: the track of structure (1) one side is gone and the track is located the barrier, and the opposite side track is located ground, and when both formed the difference in height, the second was prevented inclining pole (8.2) and is rotated under servo gear motor's (8.5) effect, makes third prevention incline pole (8.3) be located low point one side, and first rotatory servo motor (8.6) drive third prevention incline pole (8.3) and rotate, makes turning lever (8.31) support in ground for the track structure of going (1) steady side passes through the barrier.

9. The gas monitoring device for disaster prevention and sealing of the goaf injected with the flue gas of the power plant according to claim 7, wherein: the one end of track structure (1) of traveling is located the barrier, and the other end is located ground, and when both formed the difference in height, the second was prevented inclining pole (8.2) and is rotated under servo gear motor's (8.5) effect, made third prevent inclining pole (8.3) be located low point one side, and first rotatory servo motor (8.6) drive third prevent inclining pole (8.3) and rotate, made turning lever (8.31) support in ground for the track structure of traveling (1) is steady openly through the barrier.

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