Deslagging box for gas drainage pipeline
By setting up a driving motor and timer in the gas extraction pipeline deslag removal box, the gears and worm teeth cooperate to drive the valve to rotate, and automatic opening and closing is achieved, which solves the problem of automatic opening and closing and timing automatic slag discharge functions, and improves the System stability and operating efficiency.
Patent Information
- Application Number
- CN202411498492.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-25
- Publication Date
- 2025-01-14
AI Technical Summary
The existing gas extraction pipeline slag removal box cannot automatically control the opening and closing of the valve, and it is difficult to twist the valve during slag discharge operation, which lacks the function of automatic slag discharge at regular intervals, resulting in long-term blockage.
By setting up a driving motor and a timer, the gears and worm teeth are driven to rotate together to drive the valve, and the start of the driving motor is controlled through the timer, which realizes automatic opening and closing of the upper and lower valves, solving the lack of functions of screwing and automatic slag discharge at regular intervals.
The automatic slag discharge function of the gas extraction pipeline deslag box is realized, reducing the frequency of manual maintenance, avoiding blockage problems, and improving the stable operation of the system.
Smart Images

Figure CN119308721A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of gas extraction pipes, and in particular to a gas extraction pipeline slag removal box. Background Art
[0002] In the process of coal mining, gas is a common and potentially dangerous gas. The main component of gas is methane. If it is not properly handled, it may cause serious safety accidents such as explosions. Therefore, gas extraction is one of the key links in coal mine safety production. Through gas extraction, the concentration of gas in the mine can be reduced and the risk of gas accidents can be reduced. In the process of gas extraction, due to the complexity of the coal seams and gas extraction environment in the mine, the gas extraction pipeline often carries a large amount of dust solid particles, coal slag, coal slime and other impurities. These impurities flow in the pipeline with the gas, which can easily cause pipeline blockage and reduce gas extraction efficiency. Even the blocked gas extraction pipeline needs to be frequently cleaned and maintained, affecting the normal and stable operation of the gas extraction system in the local area of the mine. Therefore, a slag remover is added to the gas extraction pipeline, and personnel are regularly arranged to clean and remove slag.
[0003] The existing gas extraction pipeline slag removal box cannot automatically open and close the control valve when in use. It is rather laborious to turn the valve during slag discharge operations. In addition, it lacks the function of timed automatic slag discharge in daily use. If it is not cleaned for a long time, it is easy to cause blockage.
[0004] Therefore, in view of the above-mentioned existing gas extraction pipeline slag removal box being unable to automatically open and close the control valve when in use, it is rather laborious to turn the valve during slag discharge operations, and the lack of the function of timed automatic slag discharge in daily use, and the problem of easy blockage if not cleaned for a long time, a gas extraction pipeline slag removal box can be designed. By setting a driving motor, its output end can drive the gear to rotate during operation, and the gear can drive the turntable to rotate in cooperation with the meshing teeth on the side of the turntable, and the turntable drives the worm gear on its surface to rotate synchronously, and the worm gear can drive the knobs of the upper valve and the lower valve to rotate in cooperation with the worm wheel, and by setting a timer and a controller, the staff can adjust the timer and input the interval time for the drive motor to start. At each time interval, the timer will transmit a signal to the controller to control the corresponding drive motor to operate, thereby realizing the automatic opening and closing of the upper valve and the lower valve. Summary of the invention
[0005] In order to overcome the problem that the existing gas extraction pipeline slag removal box cannot automatically open and close the control valve when in use, it is relatively difficult to turn the valve during slag discharge operations, and there is a lack of timed automatic slag discharge function in daily use, which can easily cause blockage if not cleaned for a long time.
[0006] The technical scheme of the present invention is: a gas extraction pipeline slag box, including a slag remover; also including an upper valve, a lower valve, a worm gear, a bracket, a driving motor, a gear, a turntable, meshing teeth, a worm gear, a timer and a controller, a straight pipe is arranged at the middle position of the bottom surface of the slag remover, the bottom of the straight pipe is connected with the slag remover box body, a guide cover is arranged on the bottom surface of the guide cover, a mounting plate is arranged on the bottom surface of the mounting plate, a slag discharge pipe is arranged on the bottom surface of the mounting plate, an upper valve is arranged inside the straight pipe, a lower valve is arranged inside the slag discharge pipe, the outer surfaces of the knobs of the upper valve and the lower valve are both sleeved with worm gears, and the slag remover box body is provided with a guide cover, a mounting plate is arranged on the bottom surface of the guide cover, a slag discharge pipe is arranged on the bottom surface of the mounting plate, an upper valve is arranged inside the straight pipe, a lower valve is arranged inside the slag discharge pipe, and the outer surfaces of the knobs of the upper valve and the lower valve are sleeved with worm gears. A bracket is provided on the front position of the upper surface of the body and the bottom surface of the mounting plate, a driving motor is provided on the mounting surface of the bracket, a gear is connected to the output end of the driving motor, a turntable is rotatably connected to the lower side of the outer surface of the straight tube and the upper side of the outer surface of the slag discharge pipe, the outer surface of the turntable is provided with meshing teeth, the meshing teeth are meshed with the gears, a plurality of circumferentially distributed worm teeth are provided on the side surface of the turntable close to the corresponding gear, the worm teeth are meshed with the worm wheel, a timer is installed on the left position of the front side surface of the slag removal box body, a controller is provided on the front side surface of the slag removal box body at the side of the timer, and the timer, the controller and the driving motor are electrically connected.
[0007] Preferably, by setting a driving motor, its output end can drive the gear to rotate during operation, and the gear can drive the turntable to rotate in cooperation with the meshing teeth on the side of the turntable, and the turntable drives the worm gear on its surface to rotate synchronously, and the worm gear can drive the knobs of the upper valve and the lower valve to rotate in cooperation with the worm wheel, and by setting a timer and a controller, the staff can adjust the timer and input the interval time for starting the driving motor. At each time interval, the timer will transmit a signal to the controller to control the corresponding driving motor to operate, thereby realizing automatic opening and closing of the upper valve and the lower valve, so as to achieve the purpose of automatic slag discharge, so as to solve the problem that the existing gas extraction pipeline slag removal box cannot automatically open and close the control valve when in use, and it is more laborious to turn the valve during slag discharge operation, and lacks the function of timed automatic slag discharge in daily use, and requires regular inspection and maintenance by the staff.
[0008] Preferably, sliding bars are symmetrically arranged on both sides of the inner surface of the slag removal box body, the outer surfaces of the four sliding bars are slidably connected with first magnetic blocks, and scraping bars are arranged between each of the four first magnetic blocks.
[0009] Preferably, slide grooves are symmetrically provided on the left and right sides of the outer surface of the slag removal box body, the interior of the slide grooves is slidably connected with second magnetic blocks, the first magnetic blocks and the corresponding second magnetic blocks are attracted to each other, and a pull rod is provided between the two corresponding second magnetic blocks.
[0010] Preferably, limiting grooves are provided on both the front and rear sides of the inner surface of the slide slot, and limiting blocks are installed on both the front and rear side surfaces of the second magnetic block, and the limiting blocks are slidably connected to the limiting grooves.
[0011] Preferably, flanges for docking with the gas pipeline are provided at the pipeline openings on both sides of the left side of the slag remover.
[0012] Preferably, a first frame is provided at a middle right position of the inner surface of the slag remover, and a filter screen is provided on the inner surface of the first frame.
[0013] Preferably, a second frame is provided on the right side of the inner surface of the slag remover, and a cotton mesh is provided on the inner surface of the second frame.
[0014] Preferably, the connection between the straight pipe and the slag discharge pipe and the slag removal box body and the slag removal box body are all sealed.
[0015] Preferably, the slag removal box body is made of stainless steel as a whole, and the inner lining of the slag removal box body is surrounded by carbon steel anti-corrosion material. The size of the slag removal box body is 500mm long*400mm wide*400mm high.
[0016] Preferably, the diameters of the upper valve and the lower valve are both 300 mm.
[0017] Beneficial effects of the present invention: 1. By setting a driving motor, its output end can drive the gear to rotate during operation, and the gear can drive the turntable to rotate in cooperation with the meshing teeth on the side of the turntable, and the turntable drives the worm gear on its surface to rotate synchronously, and the worm gear can drive the knobs of the upper valve and the lower valve to rotate in cooperation with the worm wheel, so as to solve the problem that the existing gas extraction pipeline slag removal box cannot automatically open and close the control valve when in use, and it is more laborious to turn the valve during slag removal operation; 2. By setting the timer and controller, the staff can adjust the timer and input the interval time for the drive motor to start. At each time interval, the timer will transmit a signal to the controller to control the corresponding drive motor to operate, thereby realizing the automatic opening and closing of the upper valve and the lower valve, so as to solve the problem that the existing gas extraction pipeline slag removal box lacks the function of timed automatic slag removal in daily use, and requires regular inspection and maintenance by the staff. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 Shown is a schematic diagram of the three-dimensional structure of a slag removal box for a gas extraction pipeline of the present invention; Figure 2 Shown is a schematic diagram of the three-dimensional structure of a slag removal box turntable of a gas extraction pipeline of the present invention; Figure 3Shown is a schematic diagram of the three-dimensional structure of a scraper rod of a slag removal box of a gas extraction pipeline of the present invention; Figure 4 Shown is a schematic diagram of the three-dimensional structure of a slag removal box tie rod of a gas extraction pipeline of the present invention; Figure 5 Shown is a schematic diagram of a three-dimensional structure of a gas extraction pipeline slag removal box of the present invention when viewed from above; Figure 6 Shown is a schematic diagram of a half-sectioned three-dimensional structure of a slag remover body of a gas extraction pipeline slag remover box of the present invention.
[0019] Explanation of the reference numerals in the accompanying drawings: 1. slag remover; 2. straight pipe; 3. slag remover box body; 4. guide cover; 5. mounting plate; 6. slag discharge pipe; 701. upper valve; 702. lower valve; 8. worm gear; 9. bracket; 10. drive motor; 11. gear; 121. turntable; 122. meshing teeth; 123. worm gear; 13. timer; 14. controller; 15. slide bar; 16. first magnetic block; 17. scraper bar; 18. slide groove; 19. second magnetic block; 20. pull rod; 21. limit groove; 22. limit block; 23. flange; 24. first frame; 25. filter screen; 26. second frame; 27. cotton screen. DETAILED DESCRIPTION
[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0021] See also Figure 1-Figure 6The present invention provides an embodiment: a gas extraction pipeline slag removal box, including a slag remover 1; also including an upper valve 701, a lower valve 702, a worm gear 8, a bracket 9, a driving motor 10, a gear 11, a turntable 121, a meshing tooth 122, a worm gear 123, a timer 13 and a controller 14, a straight pipe 2 is arranged at the middle position of the bottom surface of the slag remover 1, the bottom of the straight pipe 2 is connected to a slag removal box body 3, a guide cover 4 is arranged on the bottom surface of the slag removal box body 3, a mounting plate 5 is arranged on the bottom surface of the guide cover 4, a slag discharge pipe 6 is arranged on the bottom surface of the mounting plate 5, the upper valve 701 is arranged inside the straight pipe 2, and the inside of the slag discharge pipe 6 A lower valve 702 is provided, and the outer surfaces of the knobs of the upper valve 701 and the lower valve 702 are sleeved with a worm gear 8. A bracket 9 is provided on the upper surface of the slag removal box body 3 and the front position of the bottom surface of the mounting plate 5. A driving motor 10 is provided on the mounting surface of the bracket 9. A gear 11 is connected to the output end of the driving motor 10. A turntable 121 is rotatably connected to the lower side of the outer surface of the straight pipe 2 and the upper side of the outer surface of the slag discharge pipe 6. The outer surface of the turntable 121 is provided with meshing teeth 122, and the meshing teeth 122 mesh with the gear 11. A plurality of circumferentially distributed worm teeth 123 are installed on the surface of one side of the turntable 121 close to the corresponding gear 11, and the worm teeth 123 mesh with the worm gear 8. A timer 13 is installed on the left side of the front surface of the slag removal box body 3, and a controller 14 is arranged on the side of the timer 13 on the front surface of the slag removal box body 3. The timer 13, the controller 14 and the driving motor 10 are electrically connected. By setting the driving motor 10, its output end can drive the gear 11 to rotate during operation. The gear 11 can drive the turntable 121 to rotate in cooperation with the meshing teeth 122 on the side of the turntable 121. The turntable 121 drives the worm gear 123 on its surface to rotate synchronously. The worm gear 123 can drive the knobs of the upper valve 701 and the lower valve 702 to rotate in cooperation with the worm gear 8, and By setting the timer 13 and the controller 14, the staff can adjust the timer 13 and input the interval time for starting the drive motor 10. At each time interval, the timer 13 will transmit a signal to the controller 14 to control the corresponding drive motor 10 to operate, thereby realizing the automatic opening and closing of the upper valve 701 and the lower valve 702, so as to achieve the purpose of automatic slag discharge, so as to solve the problem that the existing gas extraction pipeline slag removal box cannot automatically open and close the control valve when in use, and it is more laborious to turn the valve during slag discharge operations, and lacks the function of timed automatic slag discharge in daily use, and the staff needs to regularly check and maintain it.
[0022] See also Figure 1-Figure 6In this embodiment, sliding bars 15 are symmetrically arranged on the left and right sides of the inner surface of the slag removal box body 3, and the outer surfaces of the four sliding bars 15 are slidably connected with first magnetic blocks 16, and scraping bars 17 are arranged between the four first magnetic blocks 16. By arranging the sliding bars 15, the first magnetic blocks 16 can slide on their outer surfaces, thereby driving the sliding bars 15 to clean the inner surface of the slag removal box body 3, and the outer surface of the slag removal box body 3 is symmetrically provided with sliding grooves 18 on the left and right sides, and the interior of the sliding grooves 18 is slidably connected with second magnetic blocks 19, and the first magnetic blocks 16 and the corresponding second magnetic blocks 19 are adsorbed on each other, and a pull rod 20 is arranged between the two corresponding second magnetic blocks 19. By arranging the sliding grooves 18, when the pull rod 20 is pulled, the second magnetic blocks 19 can slide inside them, and at the same time drive the first magnetic blocks adsorbed thereon to move. The block 16 moves, and this transmission method does not require opening holes on the side surface of the slag removal box, which effectively ensures the airtightness of the slag removal box body 3. Limiting grooves 21 are provided on the front and rear sides of the inner surface of the slide 18, and limiting blocks 22 are installed on the front and rear surfaces of the second magnetic block 19. The limiting blocks 22 are slidably connected with the limiting grooves 21. By setting the limiting grooves 21 and the limiting blocks 22, the position of the second magnetic block 19 can be limited to ensure that the second magnetic block 19 is always located in the vertical direction for sliding, thereby improving the stability of the structural operation. The pipeline openings on both sides of the left side of the slag remover 1 are provided with flanges 23 for docking with the gas pipeline. By setting the flanges 23, it is convenient for the staff to quickly install and dock the slag remover 1 with the gas pipeline, and the connection has a higher mechanical strength to improve the service life.
[0023] See also Figure 2-Figure 6In this embodiment, a first frame 24 is provided on the right side of the middle of the inner surface of the slag remover 1, and a filter screen 25 is provided on the inner surface of the first frame 24. The first frame 24 can be provided to facilitate the positioning and installation of the filter screen 25, and by providing the filter screen 25, during the gas extraction and transportation process, the filter screen 25 can effectively block the impurities such as coal slag, dust solid particles, etc. extracted during the suction process. After being blocked, these impurities will fall into the interior of the slag removal box body 3 through the straight pipe 2 under the action of gravity and be collected by the slag removal box body 3. A second frame 26 is provided on the right side of the inner surface of the slag remover 1, and a cotton net 27 is provided on the inner surface of the second frame 26. The second frame 26 can be provided to facilitate the positioning and installation of the cotton net 27, and the setting of the cotton net 27 can effectively absorb the moisture mixed in the gas, which is helpful to improve the purity and quality of the gas. The connection between the straight pipe 2 and the slag discharge pipe 6 and the slag removal box body 3 and the slag removal box body 3 are all sealed. By adopting a sealing design for the slag removal box body 3, impurities can be prevented The risk of leakage and gas leakage can be effectively improved. The safety of the device during use is effectively improved. The slag removal box body 3 is made of stainless steel as a whole, and the inner lining of the slag removal box body 3 is surrounded by carbon steel anti-corrosion material. The size of the slag removal box body 3 is 500mm long * 400mm wide * 400mm high. By using stainless steel material to make the slag removal box body 3 and using carbon steel anti-corrosion material as the inner lining, the slag removal box body 3 can have good corrosion resistance and wear resistance to extend the service life. The calibers of the upper valve 701 and the lower valve 702 are both 300mm. By setting the upper valve 701 and the lower valve 702, when the pipeline is flowing normally, the upper valve 701 is in an open state and the lower valve 702 is in a closed state, so that the impurities and waste residues that fall will be temporarily stored in the inside of the slag removal box body 3. When the slag discharge operation is performed, the upper valve 701 is closed and the lower valve 702 is opened, so that the regional gas extraction pipeline can continue to operate normally during the slag discharge without stopping the extraction, effectively preventing the safety hazard of excessive gas outflow and ensuring the stable operation of the gas extraction system.
[0024] During operation, the first magnetic block 16 can slide on its outer surface by setting the slide bar 15, thereby driving the slide bar 15 to clean the inner surface of the slag removal box body 3. By setting the slide groove 18, when the pull rod 20 is pulled, the second magnetic block 19 can slide inside it, and at the same time drive the first magnetic block 16 adsorbed thereon to move. This transmission method does not require opening holes on the side surface of the slag removal box, and effectively ensures the airtightness of the slag removal box body 3. By setting the limit groove 21 and the limit block 22, the position of the second magnetic block 19 can be limited to ensure the second The magnetic block 19 is always located in the vertical direction for sliding, which improves the stability of the structural operation. By setting the flange 23, it is convenient for the staff to quickly install and connect the slag remover 1 with the gas pipeline, and the connection has a high mechanical strength to improve the service life. By setting the first frame 24, it is convenient to position and install the filter 25, and by setting the filter 25, in the process of gas extraction and transportation, the filter 25 can effectively block the impurities such as coal slag, dust solid particles and so on extracted during the suction process. After being blocked, these impurities will fall into the interior of the slag removal box body 3 through the straight pipe 2 under the action of gravity and be collected by the slag removal box body 3. By setting the second frame 26, it is convenient to position and install the cotton net 27, and the setting of the cotton net 27 can effectively absorb the moisture mixed in the gas, which helps to improve the purity and quality of the gas. By adopting a sealing design for the slag removal box body 3, the risk of impurity leakage and gas leakage can be prevented, and the safety of the device during use can be effectively improved. By using stainless steel material to make the slag removal box body 3 and using carbon steel anti-corrosion material as the inner lining, the slag removal box body can be made 3 has good corrosion resistance and wear resistance to extend the service life. By setting the upper valve 701 and the lower valve 702, when the pipeline is flowing normally, the upper valve 701 is in an open state and the lower valve 702 is in a closed state, so that the impurities and waste slag that fall will be temporarily stored in the interior of the slag removal box body 3. When the slag discharge operation is carried out, the upper valve 701 is closed and the lower valve 702 is opened, so that the regional gas extraction pipeline can continue to operate normally during the slag discharge without stopping the extraction, effectively preventing the safety hazard of excessive gas outflow and ensuring the stable operation of the gas extraction system.
[0025] Through the above steps, by setting the drive motor 10, its output end can drive the gear 11 to rotate during operation, and the gear 11 can drive the turntable 121 to rotate in cooperation with the meshing teeth 122 on the side of the turntable 121, and the turntable 121 drives the worm gear 123 on its surface to rotate synchronously, and the worm gear 123 can drive the knobs of the upper valve 701 and the lower valve 702 to rotate in cooperation with the worm wheel 8, and by setting the timer 13 and the controller 14, the staff can adjust the timer 13 and input the interval time for starting the drive motor 10. At each time interval, the timer 13 will transmit a signal to the controller 14 to control the corresponding drive motor 10 to operate, thereby realizing the automatic opening and closing of the upper valve 701 and the lower valve 702, so as to achieve the purpose of automatic slag discharge, so as to solve the problem that the existing gas extraction pipeline slag removal box cannot automatically open and close the control valve when in use, and it is more laborious to turn the valve during slag discharge operation, and lacks the function of timed automatic slag discharge in daily use, which requires regular inspection and maintenance by the staff.
Claims
1. A gas extraction pipeline deslagging box, comprising a deslagging device (1); characterized in that: The invention also comprises an upper valve (701), a lower valve (702), a worm gear (8), a bracket (9), a driving motor (10), a gear (11), a rotating disk (121), meshing teeth (122), a worm gear (123), a timer (13) and a controller (14). A straight pipe (2) is arranged at the middle position of the bottom surface of the slag remover (1). The bottom of the straight pipe (2) is connected to a slag removal box body (3). A guide cover (4) is arranged on the bottom surface of the slag removal box body (3). A mounting plate (5) is arranged on the bottom surface of the guide cover (4). A slag discharge pipe (6) is arranged on the bottom surface of the mounting plate (5). An upper valve (701) is arranged inside the straight pipe (2). A lower valve (702) is arranged inside the slag discharge pipe (6). The outer surfaces of the knobs of the upper valve (701) and the lower valve (702) are both sleeved with worm gears (8). The upper surface of the slag removal box body (3) and the mounting plate (5) are connected to each other. A bracket (9) is provided at a front position of the bottom surface of the straight tube (2), a driving motor (10) is provided on the mounting surface of the bracket (9), the output end of the driving motor (10) is connected to a gear (11), a turntable (121) is rotatably connected to the lower side of the outer surface of the straight tube (2) and the upper side of the outer surface of the slag discharge tube (6), the outer surface of the turntable (121) is provided with meshing teeth (122), the meshing teeth (122) mesh with the gear (11), a plurality of circumferentially distributed worm teeth (123) are installed on a side surface of the turntable (121) close to the corresponding gear (11), the worm teeth (123) mesh with the worm wheel (8), a timer (13) is installed at a left position on the front side surface of the slag removal box body (3), a controller (14) is provided on the front side surface of the slag removal box body (3) at a side position of the timer (13), and the timer (13), the controller (14) and the driving motor (10) are electrically connected.
2. A gas extraction pipeline deslagging box according to claim 1, characterized in that: Slide bars (15) are symmetrically arranged on both left and right sides of the inner surface of the slag removal box body (3); the outer surfaces of the four slide bars (15) are slidably connected to first magnetic blocks (16); and scraper bars (17) are arranged between each of the four first magnetic blocks (16).
3. A gas extraction pipeline deslagging box according to claim 2, characterized in that: The outer surface of the slag removal box body (3) is symmetrically provided with slide grooves (18) on both left and right sides, and the interior of the slide groove (18) is slidably connected to a second magnetic block (19), the first magnetic block (16) and the corresponding second magnetic block (19) are mutually attracted, and a pull rod (20) is provided between the two corresponding second magnetic blocks (19).
4. A gas extraction pipeline deslagging box according to claim 3, characterized in that: Limiting grooves (21) are provided on both the front and rear sides of the inner surface of the slide groove (18), and limiting blocks (22) are installed on both the front and rear sides of the second magnetic block (19), and the limiting blocks (22) are slidably connected to the limiting grooves (21).
5. A gas extraction pipeline deslagging box according to claim 1, characterized in that: Flanges (23) for connecting to gas pipelines are provided at the pipeline openings on both sides of the left side of the slag remover (1).
6. A gas extraction pipeline deslagging box according to claim 1, characterized in that: A first frame (24) is provided at a middle right position of the inner surface of the slag remover (1), and a filter screen (25) is provided on the inner surface of the first frame (24).
7. A gas extraction pipeline deslagging box according to claim 1, characterized in that: A second frame (26) is provided on the right side of the inner surface of the slag remover (1), and a cotton net (27) is provided on the inner surface of the second frame (26).
8. A gas extraction pipeline deslagging box according to claim 1, characterized in that: The connection between the straight pipe (2) and the slag discharge pipe (6) and the slag removal box body (3) and the slag removal box body (3) are all designed to be sealed.
9. A gas extraction pipeline deslagging box according to claim 1, characterized in that: The slag removal box body (3) is made of stainless steel as a whole, and the inner lining of the slag removal box body (3) is surrounded by carbon steel anti-corrosion material. The size of the slag removal box body (3) is 500mm long*400mm wide*400mm high.
10. A gas extraction pipeline deslagging box according to claim 1, characterized in that: The diameters of the upper valve (701) and the lower valve (702) are both 300 mm.