Pneumatic quantitative adjustable grouting pump for anchoring

Abstract

The utility model discloses a pneumatic quantitative adjustable grouting pump for anchoring, which relates to the field of grouting pumps, and adopts the technical scheme that the pneumatic quantitative adjustable grouting pump comprises a pump frame, two or more pump bodies are arranged on the pump frame, and the pneumatic quantitative adjustable grouting pump further comprises a driving component for driving the pump bodies to work; the driving assembly comprises an air cylinder fixedly arranged on the pump frame, an adapter frame is fixedly arranged on the air cylinder, the adapter frame is fixedly connected with a cylinder body of the pump body, and a piston of the air cylinder is fixedly connected with a plunger of the pump body. The quantitative grouting device has the advantages that accurate quantitative grouting and mixture proportion control are achieved, the coal mine anchoring effect and safety are remarkably improved, and the anchoring failure risk caused by inaccurate grouting amount or improper mixture proportion is reduced; 2, the explosion-proof performance is good, safe and stable operation in dangerous environments such as gas, coal dust and the like can be realized, and potential safety hazards in coal mine production are reduced;

Description

Technical Field

[0001] The utility model relates to the field of grouting pumps, in particular to a pneumatic quantitatively adjustable grouting pump for anchoring. Background Art

[0002] In coal mining operations, anchoring technology is an important means to ensure the safety of tunnels and working faces. Injecting anchoring agents into the borehole through a grouting pump can enhance the stability of the rock mass and prevent accidents such as roof collapse and surrounding rock deformation.

[0003] However, grouting pumps are often used in environments with gas and coal dust, which places strict requirements on the explosion-proof performance of the equipment, and the operating space is often limited. Grouting pumps used for anchoring have high requirements for the explosion-proof performance of the equipment and precise requirements for the ratio of the two mixtures.

[0004] Traditional grouting pumps generally use manual rotary valves, pneumatic rotary valves, electromagnetic rotary valves, electromagnetic slide valves, mechanical slide valves and other control methods. The mechanical slide valves are mostly modified from two-position three-way mechanical valves. However, these traditional control methods have many defects, such as the inability to accurately control the single grouting volume and mixture ratio, poor adjustment performance, and high maintenance costs due to complex structure. In addition, in the complex and harsh environment of coal mines, the explosion-proof performance is difficult to meet the requirements. In addition, the existing grouting pumps lack quantitative adjustable control, and cannot flexibly adjust the grouting volume according to actual working conditions. It is difficult to meet the precise requirements of grouting volume for different anchoring operations, and can no longer adapt to the increasingly complex environment and increasingly precise mixture ratio requirements at this stage. Utility Model Content

[0005] In view of the above technical problems, the utility model provides a pneumatic quantitative adjustable grouting pump for anchoring.

[0006] The technical solution is as follows: it comprises a pump frame, on which two or more pump bodies are arranged, and also comprises a driving assembly for driving the pump bodies to work;

[0007] The driving assembly comprises a cylinder fixedly arranged on the pump frame, an adapter frame fixedly arranged on the cylinder, the adapter frame is fixedly connected to the cylinder body of the pump body, and the piston of the cylinder is fixedly connected to the plunger of the pump body.

[0008] Preferably, the adapter frame comprises a mounting plate fixedly arranged on the cylinder, a pull rod is fixedly arranged at each of the four corners of the mounting plate, a pump connecting plate is fixedly arranged at the movable end of the pull rod, and the cylinder body of the pump body is fixed on the pump connecting plate;

[0009] A cylinder connecting plate is fixedly arranged on the piston rod of the cylinder, and the cylinder connecting plates are respectively fixedly connected to the plunger of the pump body.

[0010] Preferably, an air source processing component is also fixedly arranged on the pump frame, the air inlet end of the air source processing component is connected to the air source through a pipeline, the air outlet end is connected to the main control valve through a pipeline, and the reversing valve is connected after the main control valve, and the reversing valve is used to drive the cylinder to extend and retract.

[0011] Preferably, the reversing valve is a two-position five-way valve, the air inlet end of the reversing valve is connected to the main control valve through a pipeline, the two air outlet ends of the reversing valve are respectively connected to the cylinder ports at both ends of the cylinder through pipelines, and a muffler is provided for each of the two exhaust ports of the reversing valve.

[0012] Preferably, a machine-controlled valve is respectively arranged on the cylinder heads at both ends of the cylinder, and each of the machine-controlled valves comprises an air inlet pipe and an air outlet pipe opened on the cylinder head of the cylinder, and the lower ends of the air inlet pipe and the air outlet pipe are connected through an air chamber;

[0013] The air inlet pipe is located on a side away from the cylinder piston and is connected to the air source;

[0014] A reversing port is respectively arranged at the two ends of the reversing valve, and the reversing port is connected with the air outlet pipe of one of the machine-controlled valves through a pipeline. The reversing port can control the reciprocating movement of the valve core of the reversing valve, so that the air inlet end of the reversing valve is connected with one of the air outlet ends.

[0015] Preferably, the cross section of the air chamber is formed into a horizontally placed "convex" shape, and one end of the air chamber close to the air outlet pipe is a small chamber;

[0016] A through hole is provided on the cylinder cover near the small end of the air chamber, the through hole is communicated with the interior of the cylinder, a control rod is slidably arranged in the through hole, a conical portion is arranged at one end of the control rod, an end of the conical portion away from the through hole is a large end, and the large end is located in the large chamber of the air chamber;

[0017] The other end of the control rod extends into the interior of the cylinder.

[0018] Preferably, a spring is provided between the conical portion and the air chamber;

[0019] The diameter of the large end of the tapered portion is larger than the diameter of the small end of the air chamber, and smaller than the diameter of the large end of the air chamber.

[0020] Preferably, a counter is also provided on the pump stand, and the counter is a pneumatic counter, and the counter forms a pneumatic circuit with one group of machine-controlled valves.

[0021] The beneficial effects of the technical solution provided by the embodiment of the utility model are: 1. Realizing accurate quantitative grouting and mixture ratio control, significantly improving the effect and safety of coal mine anchoring, and reducing the risk of anchoring failure caused by inaccurate grouting amount or improper mixture ratio.

[0022] 2. It has good explosion-proof performance and can operate safely and stably in dangerous environments such as gas and coal dust, reducing safety hazards in coal mine production.

[0023] 3. The structural design is simple, easy to install, operate and maintain, which reduces the use cost and maintenance difficulty of the equipment and improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the utility model.

[0025] Figure 2 This is a schematic diagram of the internal structure of the pump frame according to an embodiment of the utility model.

[0026] Figure 3 It is a schematic diagram of the structure of the cylinder, adapter frame and pump body of an embodiment of the utility model.

[0027] Figure 4 This is a schematic diagram of the structure of the reversing valve according to an embodiment of the utility model.

[0028] Figure 5 This is a schematic diagram of the cylinder structure of an embodiment of the utility model.

[0029] Figure 6 for Figure 5 An enlarged schematic diagram of part B.

[0030] Among them, the figure markings are: 1, pump frame; 2, pump body; 3, drive assembly; 5, cylinder; 6, adapter frame; 7, air source processing assembly; 8, reversing valve; 9, machine-controlled valve; 10, air inlet pipe; 11, air outlet pipe; 12, air chamber; 14, control rod; 15, tapered part; 16, spring; 17, contact switch; 18, counter; 19, air inlet end; 20, air outlet end; 21, reversing port; D, feed port; F, discharge port. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. Of course, the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0032] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0033] In the description of the invention of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention of the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention of the utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention of the present utility model, unless otherwise specified, "multiple" means two or more.

[0034] In the description of the invention of the utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention of the utility model can be understood according to specific circumstances.

[0035] Example 1

[0036] See also Figures 1 to 6 The utility model provides a pneumatic quantitative adjustable grouting pump for anchoring, comprising a pump frame 1, on which two or more pump bodies 2 are arranged, and also comprising a driving component 3 for driving the pump bodies 2 to work;

[0037] The driving assembly 3 includes a cylinder 5 fixedly mounted on the pump frame 1 , an adapter frame 6 fixedly mounted on the cylinder 5 , the adapter frame 6 is fixedly connected to the cylinder body of the pump body 2 , and a piston of the cylinder 5 is fixedly connected to a plunger of the pump body 2 .

[0038] The adapter frame 6 includes a mounting plate fixedly mounted on the cylinder 5, a pull rod is fixedly mounted on each of the four corners of the mounting plate, a pump connecting plate is fixedly mounted on the movable end of the pull rod, and the cylinder of the pump body 2 is fixed on the pump connecting plate;

[0039] A cylinder 5 connecting plate is fixedly arranged on the piston rod of the cylinder 5 , and the cylinder 5 connecting plates are fixedly connected to the plungers of the pump body 2 respectively.

[0040] When the cylinder 5 is working, the telescopic movement of the piston rod drives the connecting plate of the cylinder 5 to move, and then drives the pump body 2 to work through the plunger fixedly connected thereto, thereby realizing the grouting operation.

[0041] The structural design of the adapter frame 6 ensures a firm and effective connection between the cylinder 5 and the pump body 2. The pull rods arranged at the four corners make the force transmission more uniform and stable, thereby improving the reliability and stability of the equipment operation. The structure is simple and compact, easy to install and maintain, and reduces the production cost and maintenance cost of the equipment.

[0042] An air source processing assembly 7 is also fixedly arranged on the pump frame 1. The air inlet end 19 of the air source processing assembly 7 is connected to the air source through a pipeline, and the air outlet end 20 is connected to the main control valve through a pipeline, and is connected to the reversing valve 8 after the main control valve. The reversing valve 8 is used to drive the cylinder 5 to extend and retract.

[0043] The master control valve is a two-position three-way valve, which can control the on-off of the entire gas system more centrally and effectively, and realize the overall control of the equipment operation; when the device is out of use, the gas source can be quickly cut off by closing the master control valve to ensure the safety of operation.

[0044] The air source processing assembly 7 generally refers to a pneumatic component that assembles three air source processing components, namely, a filter, a pressure reducing valve and an oil mist collector;

[0045] The pressure reducing valve can stabilize the gas source pressure, keep the gas source in a constant state, and reduce the damage to hardware such as valves or actuators caused by sudden changes in gas source pressure;

[0046] The filter is used to clean the air source and can filter the moisture in the compressed air to prevent the moisture from entering the device along with the gas;

[0047] The oil mist device can lubricate the moving parts of the machine body, and can lubricate the parts that are inconvenient to add lubricating oil, thereby greatly extending the service life of the machine body. In the pneumatic system, the air source processing component 7 can simplify the installation and maintenance work and improve the reliability of the pneumatic system.

[0048] The reversing valve 8 is a two-position five-way valve. The air inlet end 19 of the reversing valve 8 is connected to the main control valve through a pipeline. The two air outlet ends 20 of the reversing valve 8 are respectively connected to the cylinder 5 ports at both ends of the cylinder 5 through pipelines. A muffler is respectively set at the two exhaust ports of the reversing valve 8.

[0049] When the pneumatic quantitative adjustable grouting pump used for coal mine anchoring is working, the two-position five-way reversing valve 8 plays a key role. After the compressed air is filtered and pressure-regulated by the air source processing component 7, it enters the air inlet end 19 of the reversing valve 8 through the pipeline. Then, according to the control signal, the reversing valve 8 guides the gas to one of the two air outlet ends 20, so that the gas enters the cylinder 5 port at one end of the cylinder 5, thereby controlling the extension or retraction action of the piston rod of the cylinder 5. During the reversing process, the gas discharged from the two exhaust ports of the reversing valve 8 passes through the muffler to reduce the exhaust noise.

[0050] A machine-controlled valve 9 is respectively arranged on the cylinder heads at both ends of the cylinder 5. Each machine-controlled valve 9 includes an air inlet pipe 10 and an air outlet pipe 11 opened on the cylinder head of the cylinder 5. The lower ends of the air inlet pipe 10 and the air outlet pipe 11 are connected through an air chamber 12.

[0051] The air inlet pipe 10 is located on the side away from the piston of the cylinder 5 and is connected to the air source;

[0052] A reversing port 21 is respectively provided at the two ends of the reversing valve 8, and the reversing port 21 is connected to the outlet pipe 11 of one of the machine-controlled valves 9 through a pipeline. The reversing port 21 can control the reciprocating movement of the valve core of the reversing valve 8, so that the air inlet end 19 of the reversing valve 8 is connected to one of the air outlet ends 20.

[0053] The cross section of the air chamber 12 is formed into a horizontally placed "convex" shape, and the end of the air chamber 12 close to the air outlet pipe 11 is a small chamber;

[0054] A through hole is provided on the cylinder cover near the small end of the air chamber 12, and the through hole is communicated with the interior of the cylinder 5. A control rod 14 is slidably arranged in the through hole, and a conical portion 15 is arranged at one end of the control rod 14. The end of the conical portion 15 away from the through hole is a large end, and the large end is located in the large chamber of the air chamber 12.

[0055] The other end of the control rod 14 extends to the inside of the cylinder 5 .

[0056] Under the action of the spring 16, the tapered portion 15 of the control rod 14 can be blocked with the small chamber of the air chamber 12. At this time, the air inlet pipe 10 and the air outlet pipe 11 are blocked. When the piston of the cylinder 5 moves to one end of the cylinder 5, the piston and the control rod 14 abut against each other. The continuous movement of the piston drives the control rod 14 to move. At this time, the small chamber is connected with the large chamber, the air inlet pipe 10 is connected with the air outlet pipe 11, and the gas in the air inlet pipe 10 flows through the air outlet pipe 11 to one of the ports of the reversing valve 8. The gas can push the valve core of the reversing valve 8 to move in opposite directions, so that the air inlet end 19 of the reversing valve 8 is connected with the other air outlet, thereby realizing the adjustment and control of the telescopic state of the cylinder 5. When the piston of the cylinder 5 moves to the other end of the cylinder 5, after contacting the control rod 14 of the other machine-controlled valve 9, the gas can push the valve core of the reversing valve 8 to move in opposite directions, thereby realizing the adjustment and control of the telescopic state of the cylinder 5.

[0057] This design does not require additional power supply and electronic control during the entire process, completely avoiding dangerous factors such as electric sparks, fully meeting the explosion-proof requirements in special environments such as coal mines, and greatly improving the safety and reliability of equipment used in dangerous places.

[0058] A spring 16 is provided between the conical portion 15 and the air chamber 12;

[0059] The diameter of the large end of the tapered portion 15 is larger than the diameter of the small end of the air chamber 12 , and smaller than the diameter of the large end of the air chamber 12 .

[0060] When the tapered portion 15 of the control rod 14 is not subjected to external force, the spring 16 is in a natural state, pushing the tapered portion 15 toward the small end of the air chamber 12 to achieve blocking; when the piston of the cylinder 5 moves to the end and contacts the control rod 14, the piston pushes the control rod 14 to overcome the elastic force of the spring 16 and move the tapered portion 15 away from the small end of the air chamber 12, connecting the large and small chambers of the air chamber 12.

[0061] The setting of the spring 16 enables the conical portion 15 to stably block the small end of the air chamber 12 under normal conditions, thereby ensuring the sealing and stability of the system; there is no need for a complex electrical control system, and precise control of the air path can be achieved only by relying on the mechanical structure and the action of the spring 16, thereby reducing equipment costs and the risk of failure; this simple and reliable design does not require additional power supply and electrical control, completely avoids dangerous factors such as possible electric sparks, fully meets the explosion-proof requirements in special environments such as coal mines, and greatly improves the safety and reliability of the equipment when used in dangerous places.

[0062] A counter 18 is also provided on the pump frame 1 . The counter 18 is a pneumatic counter. The counter 18 and one group of the machine-controlled valves 9 form a pneumatic circuit.

[0063] Pneumatic technology is used to replace electrical signal collection and counting, which can meet the needs of a variety of electricity-free environments.

[0064] The counter is provided with a counting air port (Z port), a reset air port (Y port), a compressed air inlet port (P port) and an output signal air port (A port). In order to ensure the stability of the air source, the P port is connected to the total air source, the Z port is connected to the air inlet port on the rear end cover of the cylinder 5, the A port is connected to the control port of the total air source switch valve, and the Y port is connected to the working port of the reset valve (if the manual reset on the front of the counter is used, it can be left unconnected and connected to an M5 plug or a muffler);

[0065] When the counter is in use, the required number of cycles (i.e. the number of cylinder operations) can be set using the preset button on the front of the counter;

[0066] The P port on the back of the counter is connected to a constant pressure (0.2-0.8MP) from the total air source; when the Z port on the back of the counter receives an air pressure greater than 0.08MP and lasts for more than 10ms, it is used as the starting point of the counting cycle; when the air pressure at the Z port is lower than 0.015MP and lasts for more than 12ms, it is used as the midpoint of the counting cycle; when the Z port receives an air pressure greater than 0.08MP and lasts for more than 10ms, it is used as the end point of the counting cycle; at the same time, the units gear of the gear set inside the counter rotates one circle, the display on the front of the counter decreases by one digit, and the first counting cycle ends.

[0067] For example, in a specific grouting operation scenario, when it is required to stop grouting after completing 100 grouting operations, the corresponding value can be set on the counter first, and the count value can be set to 100. During the operation of the grouting pump, when the cylinder 5 performs a reciprocating motion, since the cylinder connecting plate is fixed on the piston rod of the cylinder, and the cylinder connecting plate is fixedly connected to the plunger of the pump body 2, the plunger is driven to move, driving the pump body 2 to work, thereby completing a grouting operation. At this time, the front display screen of the counter decreases by one number.

[0068] Similarly, when the set count value is reached, the number on the display changes to "00000". Port A on the back of the counter will output a gas signal to the control port of the main gas source switch valve, and the main gas source control valve will switch direction, cut off the main gas source, and the first preset count cycle will end.

[0069] As the grouting operation continues, the numbers on the counter continue to decrease. When the numbers displayed on the counter return to zero, it indicates that 100 grouting operations have been completed. At this time, the grouting pump will automatically stop working, ensuring the accuracy and controllability of the grouting operation, avoiding excessive or insufficient grouting, and providing reliable technical support for coal mine anchoring operations.

[0070] The quantitative grouting operation of the grouting pump is realized through the counter. In the coal mine anchoring operation, on the one hand, slurry materials can be saved, and on the other hand, the difference in anchoring strength caused by unstable grouting volume can be avoided, the safety risks caused by insufficient or excessive grouting can be reduced, and the anchoring effect can be made more predictable and reliable.

[0071] Press the reset button on the front of the counter, or provide air pressure (0.2-0.8MP) signal to the Y port on the back of the counter through a button valve, and the display screen on the front of the counter will return to the initially set count value, entering the next round of counting cycle.

[0072] By setting different counting values ​​on the counter, the needs of grouting operations of various scales can be flexibly met, the grouting volume can be accurately controlled, and the operator can adjust the grouting plan at any time according to the project progress and actual needs, so as to achieve the best anchoring effect.

[0073] For example, in the anchoring operation of a coal mine tunnel, for a tunnel that is 100 meters long, 5 meters wide and 4 meters high, it is determined through geological survey that a specific amount of anchoring agent needs to be injected into each cubic meter of rock mass. Through calculation and experiment, the amount of grouting each time is determined to be X liters. Since the amount of grouting injected by the grouting pump each time is constant, it is known through conversion that the number of working times of the grouting pump during each grouting is N times. Then the corresponding count value (N) is set on the counter so that the grouting pump can operate accurately according to the preset grouting amount when working. When the counter reaches the set value, the grouting pump stops automatically to ensure that the anchoring effect of the entire tunnel is uniform and reliable, avoiding safety hazards caused by insufficient or excessive grouting.

[0074] In practical applications, the feeding method can be selected according to the specific working scene and needs; the hose is connected to the feed port D of the pump body 2, and the other end is connected to the injected slurry, and the self-priming function of the pump body 2 is used to realize the feeding;

[0075] The discharge port F of the pump body 2 is connected to the grouting pipe, so as to transport the slurry to the specific position where anchoring is required.

[0076] The self-priming feeding method can adapt to more complex working environments and improve the layout adaptability of the equipment; it can realize automatic feeding, reduce manual intervention, improve work efficiency, ensure the continuity and stability of grouting operations, and help improve the quality and safety of coal mine anchoring.

[0077] When the utility model is used, in the coal mine anchoring operation, the compressed air enters the air inlet end 19 of the reversing valve 8 after being filtered and pressure-regulated, thereby controlling the extension or retraction action of the piston rod of the cylinder 5.

[0078] When the piston of the cylinder 5 moves to one end of the cylinder 5, the piston abuts against the control rod, and the continuous movement of the piston drives the control rod 14 to overcome the elastic force of the spring 16 to move. At this time, the small chamber of the air chamber 12 is connected to the large chamber, and the air inlet pipe 10 is connected to the air outlet pipe 11. The gas in the air inlet pipe 10 flows through the air outlet pipe 11 to one of the reversing ports 21 of the reversing valve 8. The gas pushes the valve core of the reversing valve 8 to move in opposite directions, so that the air inlet end 19 of the reversing valve 8 is connected to the other air outlet end 20, thereby realizing the adjustment and control of the telescopic state of the cylinder 5. When the piston of the cylinder 5 moves to the other end of the cylinder 5, it contacts the control rod 14 of another machine-controlled valve 9, and repeats the above action. This cycle is repeated to realize the pneumatic quantitative adjustable grouting operation of the grouting pump.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A pneumatic quantitative adjustable grouting pump for anchoring, characterized in that: It comprises a pump frame (1), on which two or more pump bodies (2) are arranged, and also comprises a drive assembly (3) for driving the pump bodies (2) to work; The driving assembly (3) comprises a cylinder (5) fixedly arranged on the pump frame (1), an adapter frame (6) fixedly arranged on the cylinder (5), the adapter frame (6) being fixedly connected to the cylinder body of the pump body (2), and the piston of the cylinder (5) being fixedly connected to the plunger of the pump body (2); A counter (18) is also provided on the pump frame (1), and the counter (18) is a pneumatic counter.

2. The pneumatic quantitative adjustable grouting pump for anchoring according to claim 1, characterized in that: The adapter frame (6) comprises a mounting plate fixedly mounted on the cylinder (5), a pull rod being fixedly mounted on each of the four corners of the mounting plate, a pump connecting plate being fixedly mounted on the movable end of the pull rod, and the cylinder body of the pump body (2) being fixed on the pump connecting plate; A cylinder (5) connecting plate is fixedly arranged on the piston rod of the cylinder (5), and the cylinder (5) connecting plate is respectively fixedly connected to the plunger of the pump body (2).

3. The pneumatic quantitative adjustable grouting pump for anchoring according to claim 2 is characterized in that: The pump frame (1) is also fixedly provided with an air source processing assembly (7), the air inlet end (19) of the air source processing assembly (7) is connected to an air source via a pipeline, the air outlet end (20) is connected to a master control valve via a pipeline, and the master control valve is connected to a reversing valve (8) behind the master control valve, and the reversing valve (8) is used to drive the cylinder (5) to extend and retract.

4. The pneumatic quantitative adjustable grouting pump for anchoring according to claim 3 is characterized in that: The reversing valve (8) is a two-position five-way valve. The air inlet end (19) of the reversing valve (8) is connected to the master control valve via a pipeline. The two air outlet ends (20) of the reversing valve (8) are connected to the cylinder (5) ports at both ends of the cylinder (5) via pipelines respectively. A muffler is provided at each of the two exhaust ports of the reversing valve (8).

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