Pressure reducing device for down-the-hole hammer

Abstract

The invention discloses a pressure reducing device for a down-the-hole hammer, which relates to the technical field of geological drilling and mainly comprises a connector, the first end of the connector is used for being connected with the air outlet end of an air compressor, the second end of the connector is used for being connected with the down-the-hole hammer, and a one-way outlet is formed in the side wall of the connector. One part of gas entering from the first end of the connector can flow out of the one-way outlet and enter the drill hole, and the other part of gas can be used for driving the down-the-hole hammer to drill. The pressure of water in a drill hole on the down-the-hole hammer can be reduced, and the drilling efficiency is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of geological drilling, in particular to a pressure reducing device for a down-the-hole hammer. Background Art

[0002] As an efficient drilling process, down-the-hole hammer construction is often used in formations with small water volume in the hole, such as intact bedrock, with the characteristics of high efficiency and low cost. However, when using down-the-hole hammer drilling construction, when drilling to a larger hole depth, due to the excessive amount of water in the borehole, the borehole forms too high a pressure, which affects the normal operation of the down-the-hole hammer or even makes it unable to work. For this situation, there are currently several solutions: First, increase the pressure of the air compressor. In actual operation, this is usually achieved by investing in a booster. The booster can increase the output pressure of compressed air to counteract the excessive water pressure in the borehole, thereby maintaining the normal operation of the down-the-hole hammer. Second, pump out the water in the borehole, drain the excess water out of the borehole through drainage equipment, and reduce the water pressure in the hole. Third, replace other construction processes, such as using circulating mud wall drilling process. However, these methods all have obvious disadvantages. Whether it is replacing equipment or adding equipment, it takes a lot of time to carry, install and debug the equipment. The long adjustment time will cause the drilling work to be interrupted for a long time, greatly reducing the drilling efficiency, not only delaying the project progress, but also further increasing the drilling cost due to the increase in equipment investment and time cost. Therefore, a pressure reduction device for a down-the-hole hammer is urgently needed to solve the above technical problems. Summary of the invention

[0003] The object of the present invention is to provide a pressure reducing device for a down-the-hole hammer to solve the problems existing in the above-mentioned prior art, reduce the pressure of water in the borehole on the down-the-hole hammer, and ensure the drilling efficiency.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a pressure reducing device for a down-the-hole hammer, comprising a joint, wherein the first end of the joint is used to connect to the air outlet of an air compressor, the second end of the joint is used to connect to the down-the-hole hammer, a one-way outlet is provided on the side wall of the joint, a part of the gas entering the first end of the joint can flow out of the one-way outlet and enter the borehole, and the other part can be used to drive the down-the-hole hammer to drill.

[0006] In some embodiments, the joint includes a first joint and a second joint, and an impact device for impacting the down-the-hole hammer is disposed inside the second joint, the one-way outlet is disposed on the first joint, and the second joint includes an insertion portion and a sleeve portion, the insertion portion is fixedly disposed inside the sleeve portion, the insertion portion inserts into the inner wall of the first joint, and there is a flow gap between the insertion portion and the inner wall of the first joint, the sleeve portion is sleeved outside the first joint, and an air outlet is disposed at the connection between the sleeve portion and the first joint, the air outlet is connected to the one-way outlet, and a one-way valve is disposed at the one-way outlet, so that the gas can be discharged from the first joint and enter the borehole through the flow gap, the one-way valve and the air outlet in sequence.

[0007] In some embodiments, a sealing gasket is further included, wherein the inner wall of the air outlet is inclined, and the sealing gasket includes a fixing portion and a deflecting portion, wherein the fixing portion is fixedly arranged on the first joint, and the deflecting portion can fit the air outlet end of the one-way valve, and the gas discharged from the one-way valve can blow the deflecting portion to deflect.

[0008] In some embodiments, a gas-water separation block is further included, on which a plurality of spiral grooves are arranged, and the gas-water separation block is rotatably connected to the interior of the first end of the first joint, and the inlet of the spiral groove is arranged close to the first end of the first joint, and the outlet of the spiral groove is arranged close to the first end of the second joint.

[0009] In some embodiments, the impact device includes a piston and an elastic member, both ends of the elastic member are fixedly connected to the piston and the inner wall of the second end of the second joint respectively, the piston is slidably arranged in the inner cavity of the second joint, and the air entering the first end of the second joint can push the piston to press the second end of the second joint.

[0010] In some embodiments, the impact device also includes a valve seat, which is fixedly disposed inside the first joint, and a truncated cone-shaped opening is disposed inside the valve seat. The end of the piston close to the first joint is truncated cone-shaped, and the piston can extend into the interior of the valve seat and fit against the inner wall of the valve seat. A sealing gasket is disposed at the fitting position between the piston and the valve seat, and the sealing gasket is fixedly disposed on the valve seat.

[0011] In some embodiments, a positioning sleeve is further included, wherein a through hole is opened inside the positioning sleeve for gas to pass through, and the positioning sleeve is fixedly disposed inside the first joint and is located between the gas-water separation block and the valve seat to provide positioning for the valve seat.

[0012] In some embodiments, a mounting seat and a gasket are further included, wherein the mounting seat is fixedly disposed inside the second end of the second joint, the elastic member is fixedly connected to the mounting seat, and the gasket is fixedly disposed at the end of the mounting seat close to the first end of the second joint.

[0013] In some embodiments, a balancing pin is further included, which is slidably disposed at an end of the piston away from the second end of the second joint, and a sliding direction of the balancing pin is perpendicular to a movement direction of the piston.

[0014] In some embodiments, the balancing pin is a cylindrical pin.

[0015] Compared with the prior art, the present invention has achieved the following technical effects:

[0016] The pressure reducing device for a down-the-hole hammer provided by the present invention comprises a joint, wherein a first end of the joint is used to connect to an air outlet of an air compressor, and a second end of the joint is used to connect to the down-the-hole hammer. A one-way outlet is arranged on a side wall of the joint, and a part of the gas entering through the first end of the joint can flow out of the one-way outlet and enter a borehole, and the other part can be used to drive the down-the-hole hammer to drill, and the exhausted air is mixed with water in the borehole. The density of the mixed water is significantly reduced compared to that before the mixing, resulting in a decrease in water pressure. At this time, the water pressure in the upper part of the borehole is relatively small and cannot suppress the water below. The water below will move upward and be partially discharged from the borehole. The water pressure in the borehole can be significantly reduced without the aid of a water pump, thereby ensuring that the drilling efficiency is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the structure of a pressure reduction device for a down-the-hole hammer in some embodiments of the present invention;

[0019] Figure 2 for Figure 1 The enlarged view of point A in the middle;

[0020] Figure 3 It is a front view of the gas-water separation block in some embodiments of the present invention;

[0021] Figure 4 A top view of a gas-water separation block in some embodiments of the present invention;

[0022] Figure 5This is a working schematic diagram of the connection between a pressure reducing device for a down-the-hole hammer and the down-the-hole hammer in some embodiments of the present invention.

[0023] In the figure: 101-down-the-hole hammer; 1-second joint; 2-spiral groove; 3-piston; 4-valve seat; 5-sealing gasket; 6-limit block; 7-first joint; 8-gas-water separation block; 9-spring; 10-positioning sleeve; 11-spring seat; 12-balancing pin; 13-first O-ring; 14-second O-ring; 15-check valve; 16-air outlet; 17-gasket; 18-drilling hole. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The purpose of the present invention is to provide a pressure reducing device for a down-the-hole hammer to solve the problems existing in the prior art, reduce the pressure of water in the borehole on the down-the-hole hammer, and ensure the drilling efficiency.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] like Figure 1-Figure 5As shown, the present invention provides a pressure reducing device for a down-the-hole hammer, comprising a joint, wherein the first end of the joint is used to connect to the air outlet of an air compressor, and the second end of the joint is used to connect to the down-the-hole hammer 101. A one-way outlet from inside to outside is provided on the side wall of the joint, and part of the gas entering the first end of the joint can flow out of the one-way outlet and enter the borehole, and the other part can be used to drive the down-the-hole hammer 101 to drill. The gas is discharged into the borehole 18 from the one-way outlet on the joint, and the discharged air is mixed with the water in the borehole 18. The density of the mixed water is significantly reduced compared with that before mixing, resulting in a decrease in water pressure. In general, the pressure of the introduced air is less than the water pressure at the corresponding water level, which is equivalent to that the air can dilute the water in the borehole to a certain extent. At this time, the water pressure in the upper part of the borehole 18 is relatively small and can no longer suppress the water below. The water below will move upward and partially discharge from the borehole 18, and the water pressure in the borehole 18 can be significantly reduced without the help of a pump. By timely reducing the excessively high water pressure in the borehole 18, it is ensured that the down-the-hole hammer 101 can continue to work normally. This prevents the down-the-hole hammer 101 from failing to work or working abnormally due to water pressure problems, reduces drilling interruption time caused by equipment failure and adjustment, and allows drilling work to proceed continuously, thereby ensuring overall drilling efficiency. In addition, the one-way outlet design ensures the unidirectional nature of gas discharge, preventing water or other impurities in the borehole 18 from flowing back into the joint and affecting the normal operation of the device.

[0028] In some embodiments, the joint includes a first joint and a second joint, and the interior of the second joint is provided with an impact device for impacting the down-the-hole hammer 101, a one-way outlet is provided on the first joint, and the second joint 1 includes an insertion portion and a sleeve portion, the insertion portion is fixedly arranged inside the sleeve portion, the insertion portion is inserted into the inner wall of the first joint 7, and there is a flow gap between the insertion portion and the inner wall of the first joint 7, the sleeve portion is sleeved outside the first joint 7, and an air outlet 16 is provided at the connection between the sleeve portion and the first joint 7, the air outlet 16 is connected to the one-way outlet, the one-way outlet includes a receiving port and a one-way valve 15, the one-way valve is arranged in the receiving port, and the gas can be discharged from the first joint 7 and enter the borehole 18 through the flow gap, the one-way valve 15 and the air outlet 16 in sequence. The protruding portion extends into the first joint 7 and forms a flow gap, providing a special channel for gas discharge, making the gas discharge smoother. Compared with the structure without a specific channel, it can more efficiently guide the air compressed by the air compressor to flow to the one-way outlet, thereby enhancing the mixing effect of air and water in the borehole 18, and further improving the ability to reduce water pressure. In addition, the size of the flow gap can be set to be much smaller than the size of the interface between the second joint 1 and the first joint 7, ensuring that the main large amount of gas flows into the second joint 1 to support the normal operation of the down-the-hole hammer 101, and a small part flows into the borehole 18 to reduce the water pressure. A one-way valve 15 is set at the one-way outlet to accurately control the gas discharge, allowing only gas to flow from the first joint 7 to the borehole 18, effectively preventing water, impurities or pressure in the borehole 18 from flowing back into the first joint 7, and ensuring the stability of the air pressure inside the device. A stable air pressure environment is conducive to maintaining the normal operation of the down-the-hole hammer 101, avoiding abnormal operation of the down-the-hole hammer 101 due to pressure fluctuations, and improving the stability and reliability of the entire drilling system.

[0029] It should be noted that there may be other ways to implement the one-way outlet, for example, a sealing plate may be directly rotated and set on the outside of the receiving port, the sealing plate covers the outside of the receiving port of the first joint, the water pressure on the outside cannot open it, and the air on the inside can flush the sealing plate and be discharged into the drill hole.

[0030] It should also be noted that the one-way valve 15 of this embodiment is completely opened by air pressure, and when air is introduced, the one-way valve 15 opens to discharge gas. Moreover, the one-way valve 15 can also be an electromagnetic one-way valve 15, etc., which can actively control the opening and closing of the valve body and can be manually regulated, and can also achieve one-way discharge of gas. It should be noted that the first connector 7 and the second connector 1 can also be directly aligned and connected, and the second connector 1 no longer extends into the first connector 7.

[0031] In some embodiments, the pressure reducing device for the down-the-hole hammer further comprises a sealing gasket 5, the inner wall of the gas outlet 16 is arranged at an angle, the sealing gasket 5 comprises a fixing part and a deflecting part, the fixing part is fixedly arranged on the first joint 7, the deflecting part can fit the gas outlet end of the one-way valve 15, and the gas discharged from the one-way valve 15 can blow the deflecting part to deflect to fit the inner wall of the gas outlet 16. When the deflecting part fits at the receiving port, that is, when the deflecting part fits the gas outlet end of the one-way valve, the gas does not flow out of the one-way valve 15. After the gas flows out of the one-way valve 15, the gas impacts the deflecting part and blows the deflecting part away from the gas outlet end of the one-way valve 15. The inclination of the inner wall of the gas outlet 16 cooperates with the sealing gasket 5 to guide the direction of the airflow. The gas blows the deflecting part to fit the inclined inner wall, so that the airflow enters the borehole 18 at an angle, preventing the gas from vertically entering the hole. Due to the high gas pressure, the hole wall is blown directly, affecting the safety of the hole wall.

[0032] In some embodiments, the pressure reduction device for a down-the-hole hammer further includes a gas-water separation block 8, on which a plurality of spiral grooves 2 are arranged, and the spiral grooves 2 are located between the one-way outlet and the first end of the first joint, and the gas first flows through the spiral grooves 2, and then passes through the one-way outlet after being discharged from the spiral grooves 2, and the gas-water separation block 8 is rotatably connected to the inside of the first end of the first joint 7, and the inlet of the spiral groove 2 is arranged close to the first end of the first joint 7, and the outlet of the spiral groove 2 is arranged close to the first end of the second joint 1. The design of the plurality of spiral grooves 2 on the gas-water separation block 8 utilizes the principle of centrifugal force to achieve efficient gas-water separation. Since the gas discharged from the air compressor contains some water, water vapor will affect the operation of the impact device. The gas-water separation block 8 can be used to remove water. When the mixed gas containing water enters the first end of the first joint 7, the gas-water separation block 8 rotates, and the mixed gas rotates at high speed in the spiral groove 2. Due to its high density, the water is thrown to the groove wall and flows along the groove wall to the gas outlet 16, while the main majority of the gas is relatively concentrated in the center of the spiral groove 2 and moves toward the outlet, thereby achieving effective separation of gas and water, improving the purity of the gas entering the impact device, and ensuring the stable operation of the down-the-hole hammer 101. Moreover, the rotating connection method of the gas-water separation block 8 enables the kinetic energy of the gas to be improved to a certain extent during the gas-water separation process. As the gas-water separation block 8 rotates, the gas is accelerated in the spiral groove 2. When the separated gas enters the second joint 1 and flows to the impact device, it has higher energy, which enhances the impact force of the impact device on the down-the-hole hammer 101 and can improve the drilling efficiency 18 to a certain extent.

[0033] In some embodiments, the impact device includes a piston 3 and an elastic member, the two ends of the elastic member are fixedly connected to the piston 3 and the inner wall of the second end of the second joint 1, respectively, the piston 3 is slidably arranged in the inner cavity of the second joint 1, and the air entering the first end of the second joint 1 can push the piston 3 to press the second end of the second joint 1. When the air entering the first end of the second joint 1 pushes the piston 3, the pressure energy of the gas is directly converted into the mechanical energy of the piston 3, and then produces a pressing effect on the second end of the second joint 1, driving the down-the-hole hammer 101 to vibrate. The setting of the elastic member plays a good buffering role. During the movement of the piston 3, when encountering complex resistance or instantaneous impact in the borehole 18, the elastic member can absorb part of the energy to prevent the piston 3 and the second joint 1 from being damaged due to excessive impact force. At the same time, the buffering effect of the elastic member can also make the movement of the piston 3 more stable, ensure the stability of the force of the impact device on the down-the-hole hammer 101, and help the piston 3 reset.

[0034] In some embodiments, the impact device further comprises a valve seat 4, which is fixedly arranged inside the first joint 7, and a truncated cone-shaped opening is arranged inside the valve seat 4. The end of the piston 3 near the first end of the second joint 1 is a truncated cone-shaped piston, and the small end of the piston is arranged near the large end of the valve seat opening, and the large end of the piston is arranged near the second end of the second joint. The piston 3 can extend into the interior of the valve seat 4 and fit with the truncated cone-shaped opening of the inner wall of the valve seat 4, and a sealing gasket is arranged at the fitting position between the piston 3 and the valve seat 4, preferably a first O-ring 13, and the first O-ring 13 is fixedly arranged on the valve seat 4. The valve seat 4 and the piston 3 adopt a truncated cone-shaped fitting design, which is similar to a conical sealing structure and has a good sealing foundation. On this basis, the first O-ring 13 fixedly arranged on the valve seat 4 further enhances the sealing effect. The double sealing guarantee can effectively prevent gas leakage, ensure the stability of the gas pressure entering the second joint 1 for driving the piston 3, and provide a solid air pressure guarantee for the efficient operation of the impact device. The presence of the first O-ring 13 can not only improve the sealing performance, but also reduce the wear between the piston 3 and the valve seat 4. During the frequent movement of the piston 3, the first O-ring 13 plays a buffering and lubricating role, reducing the direct friction between the sealing valve seat 4 and the valve cone surface, avoiding sealing failure and equipment damage due to excessive wear, thereby extending the service life of various components of the impact device.

[0035] It should be noted that the valve seat 4 is provided with second O-rings 14 for buffering and sealing at multiple positions where the valve seat 4 extends into the first joint 7 and contacts the first joint 7. Each second O-ring 14 is arranged along the circumference of the valve seat, and multiple second O-rings 14 are arranged along the axial direction of the valve seat.

[0036] In some embodiments, the pressure reduction device for a down-the-hole hammer further includes a positioning sleeve 10, the interior of which is provided with a through hole for gas to pass through, and the positioning sleeve 10 is fixedly arranged inside the first joint 7 and located between the gas-water separation block 8 and the valve seat 4, for providing positioning for the valve seat 4. During the installation of the equipment, the positioning sleeve 10 provides an accurate positioning reference for the installation of the valve seat 4 and provides reliable positioning support for the valve seat 4, so that the valve seat 4 always maintains a stable position during operation, avoiding displacement or shaking due to vibration, impact and other factors. The stable position of the valve seat 4 can ensure a close fit with the piston 3 and maintain the normal operation of the impact device.

[0037] It should be noted that since the valve seat 4 extends into the interior of the first joint 7 and is fixedly connected, in order to ensure the stability of the valve seat 4, a limit block 6 can also be set on the inner wall of the first joint 7, and a corresponding contact point can be set on the valve seat 4. The specific contact point can be a groove, and the limit block 6 contacts the groove on the valve seat 4 to prevent the valve seat 4 from shifting.

[0038] In some embodiments, the impact device further includes a mounting seat and a washer, the mounting seat is fixedly arranged inside the second end of the second joint, the elastic member is fixedly connected to the mounting seat, and the washer is fixedly arranged at the end of the mounting seat near the first end of the second joint. Specifically, the mounting seat is a spring seat 11, the elastic member is a spring 9, the spring seat 11 is fixedly arranged inside the second end of the second joint 1, the spring 9 is fixedly connected to the spring seat 11 and arranged above the spring seat 11, and the washer 17 is fixedly arranged at the end of the spring seat 11 near the first end of the second joint 1. The fixed connection between the spring seat 11 and the spring 9 enables the spring 9 to play a more stable buffering role during work. When the piston 3 is subjected to complex resistance or instantaneous impact from the borehole 18, the spring 9 evenly disperses the force through the spring seat 11, effectively absorbs energy, and avoids damage to the piston 3 and the second joint 1 due to excessive impact force, providing more reliable protection for the impact device and ensuring the continuous progress of drilling work. The washer 17 is arranged on the spring seat 11, and the spring 9 passes through the washer 17. The piston 3 can hit the washer 17. When the piston 3 hits the washer 17, the washer 17 and the spring 9 play a double buffering role. The spring 9 first buffers and disperses the energy, and the washer 17 itself has a certain elasticity, which can further absorb the impact force of the piston 3, reduce the damage to the entire device caused by the instantaneous impact force generated by the impact of the piston 3, and ensure the stable operation of the equipment.

[0039] In some embodiments, the pressure reducing device for the down-the-hole hammer further includes a cylindrical balancing pin 12, which is slidably disposed at the end of the second end of the piston 3 away from the second joint 1, and the sliding direction of the balancing pin 12 is perpendicular to the movement direction of the piston 3. During the reciprocating motion of the piston 3, the balancing pin 12 slides inside the piston 3. When a lateral force is generated, the balancing pin 12 will generate an interaction force with the mating surface inside the piston 3. The direction of this interaction force is opposite to the direction of the lateral force and is equal in magnitude (according to the principle of force balance), thereby effectively offsetting the lateral force. For example, when the piston 3 is subjected to a rightward lateral force, the balancing pin 12 will give the piston 3 a leftward reaction force, so that the resultant force of the piston 3 in the horizontal direction is zero, ensuring that the piston 3 will not be offset due to the lateral force, ensuring that the piston 3 always moves stably along the axial direction, and providing a stable and continuous impact force for the impact device.

[0040] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A pressure reducing device for a down-the-hole hammer, characterized in that: It includes a joint, the first end of which is used to connect to the air outlet of an air compressor, the second end of which is used to connect to a down-the-hole hammer, and a one-way outlet is provided on the side wall of the joint. A part of the gas entering the first end of the joint can flow out of the one-way outlet and enter the borehole, and the other part can be used to drive the down-the-hole hammer to drill.

2. The pressure reducing device for a down-the-hole hammer according to claim 1, characterized in that: The joint includes a first joint and a second joint, and an impact device for impacting the down-the-hole hammer is arranged inside the second joint, the one-way outlet is arranged on the first joint, and the second joint includes an insertion portion and a sleeve portion, the insertion portion is fixedly arranged inside the sleeve portion, the insertion portion is inserted into the inner wall of the first joint, and there is a flow gap between the insertion portion and the inner wall of the first joint, the sleeve portion is sleeved outside the first joint, and an air outlet is arranged at the connection between the sleeve portion and the first joint, the air outlet is connected with the one-way outlet, and a one-way valve is arranged at the one-way outlet, so that gas can be discharged from the first joint and enter the drill hole through the flow gap, the one-way valve and the air outlet in sequence.

3. The pressure reducing device for a down-the-hole hammer according to claim 2, characterized in that: It also includes a sealing gasket, the inner wall of the air outlet is inclined, the sealing gasket includes a fixing part and a deflecting part, the fixing part is fixedly arranged on the first joint, the deflecting part can fit the air outlet end of the one-way valve, and the gas discharged from the one-way valve can blow the deflecting part to deflect.

4. The pressure reducing device for a down-the-hole hammer according to claim 2, characterized in that: It also includes an air-water separation block, which is provided with a plurality of spiral grooves, and the air-water separation block is rotatably connected to the inside of the first end of the first joint, and the inlet of the spiral groove is arranged close to the first end of the first joint, and the outlet of the spiral groove is arranged close to the first end of the second joint.

5. The pressure reducing device for a down-the-hole hammer according to claim 4, characterized in that: The impact device includes a piston and an elastic member, the two ends of the elastic member are fixedly connected to the piston and the inner wall of the second end of the second joint respectively, the piston is slidably arranged in the inner cavity of the second joint, and the air entering the first end of the second joint can push the piston to press the second end of the second joint.

6. The pressure reducing device for a down-the-hole hammer according to claim 5, characterized in that: The impact device also includes a valve seat, which is fixedly arranged inside the first joint. A truncated cone-shaped opening is arranged inside the valve seat. The end of the piston close to the first joint is truncated cone-shaped. The piston can extend into the interior of the valve seat and fit with the inner wall of the valve seat. A sealing gasket is arranged at the fitting point between the piston and the valve seat, and the sealing gasket is fixedly arranged on the valve seat.

7. The pressure reducing device for a down-the-hole hammer according to claim 6, characterized in that: It also includes a positioning sleeve, the interior of which is provided with a through hole for gas to pass through, the positioning sleeve is fixedly arranged inside the first joint and is located between the gas-water separation block and the valve seat, and is used to provide positioning for the valve seat.

8. The pressure reducing device for a down-the-hole hammer according to claim 5, characterized in that: It also includes a mounting seat and a gasket, wherein the mounting seat is fixedly arranged inside the second end of the second joint, the elastic member is fixedly connected to the mounting seat, and the gasket is fixedly arranged at the end of the mounting seat close to the first end of the second joint.

9. The pressure reducing device for a down-the-hole hammer according to claim 5, characterized in that: It also includes a balancing pin shaft, which is slidably arranged at the end of the piston away from the second end of the second joint, and the sliding direction of the balancing pin shaft is perpendicular to the moving direction of the piston.

10. The pressure reducing device for a down-the-hole hammer according to claim 9, characterized in that: The balancing pin is a cylindrical pin.

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