Liquid impact prevention compressor cylinder body structure, compressor and wellhead natural gas compression method

Abstract

The invention discloses an anti-liquid-impact compressor cylinder structure, a compressor and a wellhead natural gas compression method, and relates to the technical field of compressors, the cylinder structure comprises a cylinder barrel and a piston ring assembly, a piston cavity is formed in the cylinder barrel, the cylinder structure further comprises a partition plate, the partition plate divides the piston cavity into a working cavity and a buffering cavity, and the piston ring assembly is arranged in the working cavity; the communication channel is used for realizing mutual communication of the working cavity and the buffer cavity on the two sides of the partition plate; the partition plate is configured in the mode that when the pressure difference between the pressure of the working cavity and the pressure of the buffer cavity exceeds a set threshold value, the fixed relation of the partition plate in the piston cavity is damaged under the pressure difference between the two sides of the partition plate, the partition plate can move towards the side where the buffer cavity is located under the pressure difference, the compressor comprises the cylinder body structure, and the compression method is achieved based on the cylinder body structure. According to the scheme, the maximum pressure in the cylinder is reduced by adopting a method of expanding the clearance volume of the cylinder body when the liquid impact phenomenon occurs, and the response speed in the clearance volume expanding process can be effectively optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to an anti-liquid-hammer compressor cylinder structure, a compressor, and a wellhead natural gas compression method. Background Art

[0002] The role of a wellhead natural gas compressor in natural gas extraction is to pressurize the natural gas from the wellhead and transport the pressurized natural gas to the exhaust pipeline. In the prior art, according to the flow rate requirements and the requirements for the pressure magnitude after pressurization, compressors for this purpose mostly use positive displacement compressors, such as piston compressors.

[0003] There are significant differences in the working conditions between wellhead natural gas compressors and natural gas compressors in other scenarios, including the medium characteristics of the medium to be processed. For example, well stream not only has a gas-phase component but also may contain liquid water and high-concentration water vapor. Regarding the liquid water (wellhead water production), its sources include edge water or bottom water advancement, interlayer water breakthrough, fracturing fluid backflow, etc. For the wellhead, there are control measures in the prior art for production control, water shutoff control, etc. For the compressor, to prevent liquid hammer, there are control measures such as setting a separator (solid / liquid / gas three-phase separator) on the inlet side of the compressor. In the prior art, wellhead water production monitoring measures such as downhole pressure gauges, underwater acoustic intensity monitoring sensors, and gas-liquid ratio sensors can predict wellhead water production in advance. Through early control, the risk of the compressor inhaling liquid water from the wellhead and causing liquid hammer can be reduced. However, when there is a sudden large amount of water production and the wellhead separator fails, it is still possible for the compressor to directly inhale liquid water and cause the compressor to experience liquid hammer. When the liquid hammer phenomenon occurs, depending on the moisture content in the piston compression chamber, the possible situations include an instantaneous strong impact, resulting in the instant destruction of the piston, connecting rod, cylinder block, cylinder head, etc.

[0004] In the prior art, to avoid such extreme fluid impact events as liquid hammer occurring on the compressor, in addition to the above-mentioned isolation protection measures for effectively separating liquid water before the medium enters the compressor, technical solutions such as the patent application No. CN202310457006.0 (title: A cylinder structure and its working method for preventing liquid hammer in a reciprocating piston compressor) have also been proposed. In this solution, the internal pressure is used to push open the pressure relief channel to release the internal pressure, achieving the purpose of protecting the compressor. However, the physical essence of this means is the same as the way of relieving pressure by the conventional exhaust valve on the compressor. In the face of an instantaneous liquid hammer phenomenon, it is impossible to effectively complete the pressure relief before the liquid hammer generates a strong impact (this is also the reason why there is an exhaust valve on the cylinder structure, but the exhaust valve cannot prevent the liquid hammer phenomenon from occurring).

[0005] The technical means for preventing liquid hammer in the compressor cylinder block structure is a supplement to the function of the separator in preventing liquid hammer in the compressor system. Further optimizing the technical means for preventing liquid hammer in the compressor cylinder block structure undoubtedly has important significance for promoting the orderly and efficient production of wellhead natural gas. Summary of the Invention

[0006] In response to the above-mentioned problem of optimizing the liquid-hammer prevention technology of the compressor cylinder block structure, the present invention provides a liquid-hammer prevention compressor cylinder block structure, a compressor, and a wellhead natural gas compression method. This solution uses the method of expanding the clearance volume of the cylinder block to reduce the maximum pressure in the cylinder when the liquid-hammer phenomenon occurs. This technical solution can effectively optimize the response speed of the clearance volume expansion process.

[0007] In response to the above problems, the liquid-hammer prevention compressor cylinder block structure, compressor, and wellhead natural gas compression method provided by the present invention solve the problems through the following technical key points: The liquid-hammer prevention compressor cylinder block structure includes a cylinder barrel and a piston ring assembly. A piston cavity is provided on the cylinder barrel, and further includes a partition fixed inside the piston cavity. In the axial direction of the piston cavity, the partition isolates the piston cavity into a working cavity and a buffer cavity. The piston ring assembly is arranged in the working cavity, and further includes a communication channel provided on the cylinder barrel and / or the partition. The communication channel is used to connect the working cavity and the buffer cavity on both sides of the partition; The partition is configured such that when the pressure difference between the working cavity pressure and the buffer cavity pressure exceeds a set threshold, the fixing relationship of the partition in the piston cavity is damaged under the pressure difference on both sides of the partition, and the partition can move toward the side where the buffer cavity is located under this pressure difference.

[0008] This solution aims at the following problems: For the liquid water that has entered the compressor compression cavity (i.e., the above-mentioned working cavity) or the liquid water formed in the compression cavity, in the existing method of using the internal pressure in the compression cavity to push open the pressure relief channel, the opening of the pressure relief channel needs to overcome the mechanical inertia of the valve core, spring, etc. During the continuous increase of the pressure in the compression cavity, due to the above mechanical inertia, the pressure relief channel is not opened in time. Especially when the liquid water occupies a large volume in the compression cavity, the rapidly increasing internal pressure in the compression cavity will still cause serious liquid-hammer phenomena in the cylinder block structure, resulting in direct damage to the compressor parts or accelerating the fatigue of the parts. The high failure rate of the compressor cylinder block structure seriously affects the orderly and efficient production of wellhead natural gas.

[0009] This solution utilizes the connection effect generated by the connecting channel to reduce the pressure difference between the working chamber and the buffer chamber on both sides of the partition, so as to form a working chamber pressure boundary with a thinner partition. When a water hammer phenomenon occurs in the working chamber, due to the smaller mechanical inertia of the thinner partition, when the partition moves towards the buffer chamber to expand the volume of the working chamber, the partition can be efficiently accelerated to rapidly expand the volume of the working chamber, thereby achieving the goal of improving the response speed of the inner cavity expansion of the cylinder block structure under the water hammer phenomenon and reducing the negative impact of the water hammer phenomenon on the compressor cylinder block structure.

[0010] Specifically, the maximum pressure that the piston ring assembly can reach when moving and compressing the wellhead natural gas in the working chamber is related to the clearance of the working chamber (the clearance itself also serves as a space for containing liquid water and directly participates in the protection against water hammer damage). However, due to the unstable composition of the well stream of the wellhead natural gas, when the volume of liquid water directly entering the cylinder block structure and / or the liquid water generated during the compression process exceeds the buffer capacity of the inherent clearance in the cylinder block structure, after the liquid water fills too much space in the working chamber, a serious water hammer phenomenon will occur, causing direct damage to the cylinder block structure or affecting the service life of related parts.

[0011] In this solution, the piston chamber is divided into a working chamber and a buffer chamber by a partition plate. At the same time, the piston ring assembly is arranged in the working chamber. In this way, when the cylinder block structure normally compresses the wellhead natural gas, the working chamber is the compression chamber, and the partition plate forms the pressure boundary of the compression chamber. When there is no liquid water or only a small amount of liquid water in the working chamber, the clearance in the lower working chamber will not cause the pressure in the working chamber to rise sharply to a large pressure. In this state, the cylinder block structure can operate normally, that is, the phenomenon of liquid hammer will not occur. However, when there is liquid water in the working chamber that occupies a larger volume of the working chamber during the gas compression process, these liquid waters make the effective clearance of the working chamber smaller. During this process, it will cause the pressure in the working chamber to rise sharply to a large pressure, and the volume of the liquid water is proportional to the pressure increase value and the maximum pressure value. In this solution, on the one hand, it is configured that the fixed relationship of the partition plate in the piston chamber can be broken under the corresponding pressure difference, and the partition plate can move towards the side where the buffer chamber is located under this pressure difference. In this way, when the presence of liquid water in the piston chamber causes the pressure in the working chamber to rise sharply to a large pressure and makes the pressure difference exceed the set threshold (the size of this set threshold needs to be set according to the compressor efficiency, exhaust pressure, etc. For the wellhead natural gas compressor, it can be set to 0.When the pressure is between 5 Mpa and 2 Mpa, the partition plate moves towards the buffer cavity side due to the destruction of the original fixing relationship, enabling the volume of the working cavity to rapidly expand. The expansion of this volume, relative to the fixed stroke range of the piston ring assembly, is equivalent to the expansion of the clearance in the working cavity. That is, after the original fixed state of the partition plate is destroyed, the continuous increase in the pressure in the working cavity is curbed. Thus, this solution provides a technical solution for reducing the maximum pressure in the cylinder when water hammer occurs by expanding the clearance volume of the cylinder block. On the other hand, to ensure the working efficiency of the compressor, the compressor needs to have a stable compression cavity boundary during normal operation. This solution also includes a communication channel, which is used to achieve that when the pressure in the compression cavity increases, the pressure in the buffer cavity can lag behind the increase in the pressure in the compression cavity. By sacrificing part of the compression efficiency, this solution uses the pressure balancing effect of the communication channel to reduce the pressure difference between the two sides of the partition plate and maintain the necessary pressure boundary in the working cavity. In this way, from the requirement of the partition plate's compressive capacity, by reducing the pressure difference, the partition plate can be made thinner (for example, when there is no communication channel, a partition plate that meets the fatigue and compressive capacity requirements needs to use a steel plate more than 20 mm thick. After using the communication channel to reduce the pressure difference between the two sides of the partition plate, a partition plate that meets the fatigue and compressive capacity requirements only needs to use a 5 mm thick steel plate). When the volume of liquid water in the working cavity is large, resulting in water hammer and causing the pressure in the working cavity to rise sharply (depending on the moving speed of the piston and the volume of liquid water in the compression cavity, the pressure in the compression cavity can increase several times faster than the normal pressure growth rate. The throttling effect of the communication channel causes the pressure difference between the two sides of the partition plate to rise sharply. This throttling effect is also used to enable the cylinder block structure to maintain an appropriate compression efficiency). When the pressure difference reaches the set threshold and causes the fixed relationship to be destroyed, the thinner partition plate has lower mechanical inertia. Therefore, the partition plate can move towards the buffer cavity side at a faster speed under this pressure difference to expand the clearance volume. Compared with the prior art, which relies on the opening of the exhaust valve and the opening of the pressure relief channel, and the response is affected by mechanical inertia and lags behind the increase in the internal pressure of the compression cavity, before the corresponding valve plate is fully opened, the cylinder block structure has been damaged due to water hammer. This solution can effectively optimize the response speed of the clearance volume expansion process, reduce the maximum pressure in the piston cavity of the cylinder block structure when water hammer occurs, and better provide anti-water hammer protection for the cylinder block structure.

[0012] Meanwhile, for those skilled in the art, when the fixing relationship of the partition in the piston chamber is damaged, the original clearance in the working chamber is damaged, and the original buffer chamber forms an abnormal clearance in the working chamber. To ensure the exhaust pressure and efficiency of the compressor, the compressor needs to be shut down for repair at this time. Specifically, the partition is replaced / reset in the piston chamber and then the compressor is restarted. Although this process will also cause compressor failures and necessary downtime, compared with the direct damage or reduced lifespan of the cylinder block structure caused by liquid hammer phenomenon, this solution can effectively reduce the usage cost of the compressor and shorten the downtime (when repairing with this solution, only the partition needs to be reset, and it is not easy to have major repairs caused by multiple parts being damaged due to liquid hammer).

[0013] A further technical solution of the liquid-hammer-proof compressor cylinder block structure is as follows: A fixing ring is arranged on the outer periphery of the partition. The fixing ring is an annular structure coaxial with the partition. A second sealing ring is arranged on the outer side of the fixing ring, and the second sealing ring is used to achieve axial sealing of the gap between the fixing ring and the wall of the piston chamber; It also includes an end plate fixed to the end of the cylinder barrel. The fixing ring is connected to the end plate through an adjusting mechanism, and the adjusting mechanism is used to adjust the position of the fixing ring on the axis of the piston chamber.

[0014] The above solution aims to provide a specific form of fixing the partition plate in the piston cavity. Specifically, the fixing ring serves as the outer ring of the outer circumference of the partition plate. The partition plate is fixed to the fixing ring, and the fixing ring is connected to the end plate through an adjusting mechanism. That is, a technical solution is provided in which the partition plate is connected to the adjusting mechanism through the fixing ring, and the specific connection position is on the end plate. In the above structural arrangement, by utilizing the characteristics that the fixing ring can be processed thicker than the partition plate and all positions on the outer circumference of the partition plate are connected to the fixing ring, the ability of the partition plate to resist uneven deformation at various positions in the circumferential direction during the working process of the cylinder block structure is enhanced, so as to ensure the compression efficiency and the stability of the clearance of the cylinder block structure. At the same time, in this solution, the connection of the partition plate in the piston cavity is completed based on the fixing ring, and for the processing solution that usually uses castings as the cylinder barrel blank, the existing cylinder barrel forming process does not need to be changed. The above second sealing ring is used as an axial sealing structure, and the communication ability between the working cavity and the piston cavity is only affected by the communication channel. Therefore, this solution can effectively control the communication ability to ensure the compression efficiency and the exhaust pressure of the compressor. The adjusting structure is used to adjust the position of the fixing ring on the axis of the piston cavity. When the position of the fixing ring changes, the position of the partition plate changes synchronously. Therefore, the above solution using the partition plate and the communication channel to prevent liquid hammer in the compressor cylinder block can still reasonably adjust the clearance of the working cavity according to production and the characteristics of the compressed medium. Preferably, it is set that the fixed relationship is damaged as the connection relationship between the fixing ring and the partition plate is damaged. The specific solution can be: under the pressure difference, the partition plate is disengaged from the annular groove of the fixing ring through deformation, the circumferential weld between the partition plate and the fixing ring is damaged, etc. By adopting this solution, when restoring the state of the partition plate in the piston cavity, only the reconnection of the fixing ring and the partition plate needs to be completed, and the partition plate is constrained at an appropriate position in the piston cavity through the adjusting mechanism. Such a solution that the original fixed relationship of the partition plate is damaged and the installation of the partition plate on the cylinder block structure is restored will not affect the main structure of the cylinder block structure, and has the purpose of reducing the use and maintenance costs of the cylinder block structure.

[0015] The adjusting mechanism includes a plurality of adjusting screws. The adjusting screws are circumferentially and uniformly distributed relative to the axis of the fixing ring. Each adjusting screw passes through the fixing ring and the end plate. The adjusting screw is threadedly connected to the end plate. The adjusting screw passes through the fixing ring through a through hole provided on the fixing ring, and the adjusting screw has a clearance fit with the through hole. A snap ring for restricting the position of the fixing ring in the axial direction of the adjusting screw is arranged on each adjusting screw.

[0016] The above provides a specific implementation manner of the adjusting mechanism. In this implementation manner, the clearance fit is used to enable the adjusting screw to rotate independently of the fixed ring in the through hole. By rotating the adjusting screw, the connection thread between the adjusting screw and the end plate is used to adjust the position of the adjusting screw in its axial direction. The fixed ring moves synchronously with the adjusting screw under the action of the snap ring, so as to achieve the purpose of adjusting the position of the partition plate in the piston chamber. The method of using multiple adjusting screws and arranging them evenly around the axis of the fixed ring aims to evenly support each position in the circumferential direction of the fixed ring, so as to avoid axial leakage caused by uneven circumferential pressure when the pressure on both sides of the partition plate fluctuates. In specific implementation, the adjusting screw can be processed with a boss serving as the snap ring on itself, or the snap ring can be set as a shaft retaining ring installed on the adjusting screw through an annular groove.

[0017] Each adjusting screw is configured with a spring tube. The spring tube is sleeved outside the adjusting screw. One end of the spring tube is supported on the fixed ring, and the other end is supported on the inner wall of the end plate. It further includes a locking nut threadedly connected to the adjusting screw and used to abut against the outer wall of the end plate.

[0018] In the above solution, in the state of using the adjusting screw to restrict the position of the fixed ring, the spring tube is in a compressed state under pressure, and the outer wall of the adjusting screw is in contact with the inside of the spring tube to restrict the spring tube in a stable position. The spring tube is used to achieve: when adjusting the position of the partition plate in the piston chamber by rotating the adjusting screw, the spring tube provides a thrust for the fixed ring through elastic deformation. In such an application, on the one hand, when the adjusting screws cannot be adjusted synchronously, due to the rotational resistance of a single adjusting screw becoming larger under the combined positive influence of the spring tube and the second sealing ring, when using a torque wrench to rotate each adjusting screw respectively, the above influence of the spring tube on the rotational resistance can reduce the compression amount of the second sealing ring on the side where the adjusting screw is located. In such an application, not only can the second sealing ring be protected, but also it is beneficial to maintain the coaxiality between the partition plate and the piston chamber. On the other hand, under the thrust of each spring tube, the fixed ring can be pushed to abut against the snap ring close to the working chamber. In such an application, not only can the spring tube be used to restrict the fixed ring in a relatively stable axial position of the adjusting screw, reduce the fluctuation of the assembly formed by the fixed ring and the partition plate under the pressure difference on both sides, so as to optimize the working stability of the compressor, but also the clearance size in the clearance fit can be set slightly larger to improve the convenience of adjusting the position of the partition plate in the piston chamber.

[0019] A ring groove coaxial with the fixed ring is provided on the inner wall of the fixed ring. The edge of the partition plate is embedded in the ring groove. A circumferential weld is further provided on one side of the partition plate close to the working chamber. The circumferential weld realizes the welded connection between the partition plate and the fixed ring and the sealing of the gap between the partition plate and the fixed ring.

[0020] In the above solution, the partition is clamped inside the fixed ring by using the annular groove, so as to utilize the constraints of the front and rear side walls of the annular groove on the front and rear sides of the partition to maintain the fixing stability of the partition during the operation of the compressor without liquid hammer phenomenon. The circumferential weld is used to seal the corresponding gap to avoid the communication ability between the working chamber and the buffer chamber being damaged due to the damage of the channels other than the communication channel. Setting the circumferential weld on the side of the partition close to the working chamber aims to achieve: when the liquid hammer phenomenon occurs, the circumferential weld is damaged under the tensile force, so that the partition can be disengaged from the annular groove, achieving the purpose of destroying the fixing relationship. In specific implementation, it is preferably that the fixing ring, the partition and the circumferential weld welding forming material are all stainless steel. Under such application, when the connection position of the circumferential weld is damaged under the pressure difference, the content of debris generated due to this damage and entering the working chamber can be effectively reduced, achieving the purpose of reducing the scratching risk of the piston chamber inner wall and the piston ring assembly caused by the debris before the piston ring assembly stops moving. Since the response speed of the above clearance volume expansion process is affected by the weight of the partition, and at the same time the partition also needs to have an appropriate thickness to match the requirements for its compressive capacity and stability, a more optimal application is: the partition is set as a laminated structure of a stainless steel plate and a substrate plate, and the side of the partition close to the working chamber is made of a stainless steel plate, the side of the partition far from the working chamber is a non-stainless steel plate and a substrate plate made of a metal plate, the fixing ring is made of a stainless steel ring, and the circumferential weld welding forming material is stainless steel. Under such application, after the circumferential weld is damaged under the pressure difference, it not only has the effect of reducing the amount of generated debris, but also, compared with setting the partition as a whole stainless steel plate, on the basis of the same compressive capacity and stability characteristics, the mass of the above laminated structure is smaller (taking the substrate as a 45# carbon steel plate, a cast steel plate, a ductile iron plate, and the stainless steel plate as a 304 / 316 austenitic stainless steel plate as an example, in order to withstand the same pressure difference and maintain the stability under the alternating pressure difference, the partition made of stainless steel material needs to be designed thicker, and its material density is also slightly higher than the density of the substrate, so the final weight will be larger than that of the laminated structure partition). Therefore, this application can reduce the debris while reducing the overall mechanical inertia of the partition to facilitate the response speed.

[0021] In a specific application, it is set that the side of the annular groove close to the buffer chamber has a lead-out groove with a frustum structure, and the end with a larger diameter of the frustum structure is close to the working chamber. In this way, when the middle of the partition is recessed to a certain extent under the pressure difference on both sides, due to the weakened supporting ability of the back side of the annular groove on the partition, the partition can be more smoothly disengaged from the annular groove.

[0022] The communication channel is a communication groove provided on the wall of the piston chamber. The communication groove is a strip-shaped groove on the wall of the chamber. One end of the communication groove is located in the working chamber, and the other end of the communication groove is located in the buffer chamber; The number of the communication grooves is multiple, and the communication grooves are arranged at intervals in the circumferential direction of the piston chamber.

[0023] The above provides a specific form of the communication channel: using a communication groove provided on the wall of the piston chamber and spanning across the partition plate as the communication channel. Such a communication channel can be obtained by machining the surface of the piston chamber wall, which not only has high machining efficiency but also has the characteristics of high machining accuracy of the communication channel. The communication grooves are arranged in multiple numbers and spaced in the circumferential direction of the piston chamber to achieve: relative to the partition plate, the communication grooves form multiple communication channels in the circumferential direction of the partition plate. In this way, compared with using a single communication groove (a single communication groove has the same fluid conduction ability as the multiple communication grooves adopted in this solution), during the process of establishing a pressure difference, the more balanced air flow in the circumferential direction of the partition plate can not only reduce the influence of the air flow on the vibration of the partition plate, but also, such a method is beneficial to establishing the pressure balance at each position in the cavities of the working chamber (mainly the suction process of the compressor) and the buffer chamber (mainly the compression process of the compressor).

[0024] The communication channel is a communication hole provided on the side wall of the piston chamber. One end of the communication hole communicates with the exhaust hole of the cylinder barrel, and the other end of the communication hole communicates with the buffer chamber; It further includes an adjusting cone arranged in the communication hole, and the adjusting cone is used to adjust the fluid conduction ability of the communication hole.

[0025] The above solution provides another form of connecting channel setting, specifically: the connecting hole realizes the connection between the working chamber and the buffer chamber through the orifices at both ends thereof, and by providing an adjusting cone, the problem that the connecting groove cannot adjust the connection ability between the working chamber and the buffer chamber is solved. As described above, while the present solution uses a partition plate and a buffer chamber to achieve the function of preventing liquid hammer, it will sacrifice the efficiency of the compressor. For the discharge stage of well fluid with little or no liquid water, low liquid water content or low water vapor content, the possibility of the compressor experiencing liquid hammer is relatively low. In such a case, it is not easy for the fixing relationship of the partition plate to be damaged. Therefore, it can be set to reduce the fluid conduction ability of the connecting hole through the adjusting cone (in such an application, the pressure difference is established faster on both sides of the partition plate, and less liquid content in the working chamber can trigger the damage of the fixing relationship), so as to reduce the gas loss during the pressurization stage of the cylinder block structure and the gas volume injected from the buffer chamber into the working chamber during the suction stage, achieving the purpose of optimizing the compressor efficiency; for the discharge stage of well fluid with relatively high liquid water content or relatively high water vapor content, the possibility of the compressor experiencing liquid hammer increases. In such a case, if the conduction ability of the connecting hole is small, it is easier for the fixing relationship of the partition plate to be damaged to trigger the protection against liquid hammer damage. Therefore, it can be set to increase the fluid conduction ability of the connecting hole through the adjusting cone (in such an application, the pressure difference is established slower on both sides of the partition plate, and more liquid content in the working chamber is required to trigger the damage of the fixing relationship), so as to reduce the compressor efficiency and the exhaust pressure, enhance the adaptability of the cylinder block structure to the liquid content in the working chamber (when liquid hammer occurs, there is a greater liquid content in the working chamber), and reduce the equipment failure rate caused by the damage of the fixing relationship. As a person skilled in the art, the adjusting cone can adopt the structure of a needle valve stem, and the fluid conduction ability of the connecting hole can be adjusted by adjusting the insertion depth of the adjusting cone in the connecting hole. Setting the orifice on one side of the connecting hole on the exhaust hole aims to achieve: according to the relative positions of the working chamber and the buffer chamber, the connecting hole should be set as a bent hole with a bend, so the processing of the connecting hole should preferably adopt a scheme of first setting multiple intersecting process holes and then locally blocking some of the process holes to form the connecting hole. When adopting a structure where the process hole is connected to the hole wall at the inlet position of the exhaust hole (it is necessary to avoid the exhaust valve in any opening and closing state installed in the exhaust hole from affecting the connection between the exhaust hole and the working chamber), based on the basic configuration of the cylinder block structure where the intake hole and the exhaust hole on the cylinder barrel are generally arranged on the side of the cylinder barrel, the process hole can be set as a horizontal hole parallel to the axis of the cylinder barrel and a vertical hole along the radial direction of the cylinder barrel. The horizontal hole and the vertical hole intersect, and the outer orifices of the horizontal hole and the vertical hole are blocked by plugs respectively to complete the formation of the connecting hole.

[0026] It further includes a pressure sensor installed on the cylinder barrel, and the pressure sensor is used to monitor the pressure in the working chamber; It further includes a position sensor for monitoring the position of the piston ring assembly in the cylinder barrel; It further includes a pressure relief hole provided on the cylinder barrel, and the pressure relief hole is configured with an electromagnetic pressure relief valve for controlling the on / off of the pressure relief hole; It further includes a control module, and the control module is signal-connected to the pressure sensor, the position sensor, and the electromagnetic pressure relief valve. The signal connection is as follows: the control module receives the detection results of the pressure sensor and the position sensor, and transmits an action control signal to the electromagnetic pressure relief valve; The control module is configured to: judge whether the pressure in the current working chamber exceeds the limit according to the monitoring value of the position sensor and the monitoring value of the pressure sensor. When the judgment result is that it exceeds the limit, trigger the transmission of an action control signal to open the electromagnetic pressure relief valve to the electromagnetic pressure relief valve.

[0027] As described above, when the anti-water hammer protection is triggered by the partition plate and the buffer chamber, the original position of the partition plate in the piston chamber is damaged. At this time, the compression efficiency and exhaust pressure of the compressor are greatly affected, and the compressor needs to be restarted after the partition plate is restored. As a pre-protection for the partition plate to trigger the anti-water hammer protection, the above provides an electric control pre-protection scheme. Specifically, this scheme utilizes the characteristic that the position of the piston ring assembly in the cylinder barrel is related to the gas compression ratio in the working chamber, and uses the comparison result of the pressure associated with the pressure monitoring value and the position monitoring value to judge whether to trigger the opening of the electromagnetic pressure relief valve. For example, when the liquid water occupies the clearance in the working chamber, resulting in a significant increase in the internal pressure growth rate in the working chamber during the compression stroke of the piston ring assembly, it can be determined that the internal pressure in the working chamber at the current position of the piston ring assembly exceeds the limit, thereby triggering the opening of the electromagnetic pressure relief valve to release the internal pressure of the working chamber, achieving the above-mentioned pre-protection purpose to reduce the probability of the partition plate triggering the anti-water hammer protection.

[0028] It is easy to understand that the above electric control scheme and the partition plate scheme are respectively parallel schemes for realizing the anti-water hammer protection. The electric control scheme as the pre-stage protection aims to achieve: in the prior art, the time required for the piston ring assembly to complete one cycle of movement is short, and the cylinder barrel has the characteristic of unstable temperature. This requires that the relevant sensors complete a signal detection not only with short time consumption, high signal pickup frequency, but also with little influence of the detection accuracy on temperature. When high-precision, high-dynamic performance sensors and temperature compensation schemes are adopted, the influence of the detection delay link and detection accuracy on the water hammer protection response speed can be effectively guaranteed, but the cost of using sensors is very high, which is not conducive to the economy of compressor use. Therefore, on this basis, when the partition plate scheme is further adopted as the post-stage protection, the system requirements for the above electric control scheme can be effectively reduced to reduce the setting cost of the electric control scheme, and the effective anti-water hammer protection purpose can be achieved and the economy can be taken into account under the combined action of the above two-stage protection.

[0029] In specific implementation, it is preferred that the position sensor is a magnetostrictive displacement sensor with general precision, and the pressure sensor is a sensor based on piezoelectric crystals and metal diaphragms. Such sensors have the characteristic of low result response delay, and the electromagnetic pressure relief valve also has the characteristic of rapid action response.

[0030] Regarding the control module, to reduce the calculation response delay, the specific logic of the control module can be: calculating the difference or change rate between two adjacent pressure monitoring results, and calculating the difference or change rate between two adjacent position monitoring results, and then using the method of dividing the differences or change rates (the division is the calculation result of the pressure detection result divided by the calculation result of the position inspection result) to calculate whether the pressure in the current working chamber exceeds the limit. This logic can be implemented by software or by an analog differential circuit (signal type support is required: the analog differential circuit is only applicable to processing analog signals), but in specific selection, a solution that takes into account both cost control and calculation time consumption is preferred.

[0031] This solution also relates to a liquid-hammer-proof compressor, including a compressor cylinder block structure, and the compressor cylinder block structure is the compressor cylinder block structure provided in any one of the above. The piston ring assembly includes a ring main body made of a metal plate, the ring main body is connected to the piston rod, and further includes a self-lubricating layer made of a polymer self-lubricating material. The self-lubricating layer is in an annular structure and sleeved outside the ring main body, and further includes multiple first sealing rings installed on the outer periphery of the self-lubricating layer. The first sealing rings are arranged in sequence in the axial direction of the piston ring assembly, and the first sealing rings serve as axial sealing rings between the piston ring assembly and the wall of the working chamber.

[0032] The above liquid-hammer-proof compressor is a compressor including the compressor cylinder block structure. In summary, this solution has the characteristic of effectively optimizing the response speed of the clearance volume expansion process. Further, in view of the characteristic that the well fluid has a sand production characteristic, to reduce the influence of related abrasive particles in the fluid on the piston ring assembly and the wall of the piston chamber, a self-lubricating layer made of polytetrafluoroethylene material is provided on the outer periphery of the ring main body, and a first sealing ring is provided on the basis of the self-lubricating layer, aiming to achieve: using the characteristic that abrasive particles can be embedded in the polytetrafluoroethylene self-lubricating polymer material to reduce the content of free abrasive particles in the piston chamber, so as to reduce the influence of abrasive particles on the wall of the piston chamber.

[0033] This solution also relates to a wellhead natural gas compression method, which is realized based on the compressor cylinder block structure described in any one of the above. The method is as follows: The piston ring assembly reciprocates in the working chamber to compress the wellhead natural gas. During the process of the piston ring assembly compressing the wellhead natural gas, the working chamber and the buffer chamber are connected by using the communication channel to reduce the pressure difference on both sides of the partition. When the pressure difference exceeds the set threshold, the fixed relationship of the diaphragm in the piston cavity is destroyed under the pressure difference on both sides of the diaphragm, and the diaphragm can move toward the side where the buffer cavity is located under the pressure difference; The compressor cylinder adopts a single-cylinder single-stage compression method that compresses wellhead natural gas only when the piston ring assembly moves forward or backward, or adopts a single-cylinder two-stage compression method in which air inlet holes and exhaust holes are provided at both ends of the cylinder barrel, and the wellhead natural gas on one side of the piston ring assembly is compressed when the piston ring assembly moves forward or backward; When the compressor cylinder adopts a single-cylinder single-stage compression mode, the partition is set on the side of the piston ring assembly away from the piston rod. The piston ring assembly compresses the wellhead natural gas when it moves toward the side where the partition is located. The channel opening of the communication channel set on the cylinder is located at the end of the working chamber close to the partition. When the compressor cylinder adopts a single-cylinder two-stage compression method, the partition is arranged on the side of the piston ring assembly away from the piston rod, and the channel opening of the connecting channel arranged on the cylinder is located at the end of the working chamber close to the partition, and the working chamber is used as: the working chamber between the partition and the piston ring assembly is used as the first-stage compression chamber, and the working chamber on the side of the piston ring assembly away from the partition is used as the second-stage compression chamber. The second-stage compression chamber is used to re-pressurize the wellhead natural gas after the first-stage compression chamber is pressurized.

[0034] The above method is a method for realizing wellhead natural gas compression based on the compressor cylinder structure, and further explains the setting method of the partition under the specific compression mode of the compressor cylinder: the buffer chamber is located on the side of the piston ring assembly away from the piston rod, so that after the fixed relationship is destroyed, the conductivity between the formed working chamber and the buffer chamber is used to quickly prevent the internal pressure in the piston chamber from further increasing. Compared with setting the buffer chamber on the side of the cylinder or the end where the piston rod is located, the purpose of optimizing the response speed of the clearance volume expansion process is achieved. The selection of the position of the channel mouth of the above connecting channel enables the piston ring assembly to use the connecting channel to establish a continuously increasing pressure difference on both sides of the partition during the entire compression stroke.

[0035] The above scheme illustrates the relationship between the working chambers on both sides of the piston ring assembly at different stages of wellhead natural gas pressurization when the compressor cylinder adopts a single-cylinder two-stage compression method. It is intended to address the following problems: the medium processed by the secondary compression chamber is the medium discharged from the primary compression chamber, stored in the buffer tank, and separated from the water and gas. Therefore, the primary compression chamber is more susceptible to the water content of the well flow and liquid hammer occurs. In this context, a partition is provided to provide liquid hammer protection for the primary compression chamber. This pressurization method not only has the high compression efficiency of the single-cylinder two-stage compression method, but also uses the partition to provide high-response liquid hammer protection for the wellhead natural gas, so that the wellhead natural gas compression not only has the characteristics of high compression efficiency, but also has the characteristics of reliable liquid hammer protection.

[0036] The present invention has the following beneficial effects: This solution is configured such that the fixed relationship of the partition in the piston chamber can be broken under the corresponding pressure difference, and the partition can move towards the side where the buffer chamber is located under this pressure difference. In this way, after the original fixed state of the partition is broken, the continuous increase in the pressure of the working chamber is curbed. That is, this solution provides a technical solution for reducing the maximum pressure in the cylinder when water hammer occurs by expanding the clearance volume of the cylinder block.

[0037] This solution is also provided with a communication channel, which can achieve: using the pressure balancing effect exerted by the communication channel to reduce the pressure difference on both sides of the partition and maintain the necessary pressure boundary of the working chamber. In this way, from the requirement of the partition's compressive capacity, by reducing the pressure difference, the partition can be made thinner. When the volume of liquid water in the working chamber is large, resulting in water hammer and a sharp increase in the pressure of the working chamber, after the fixed relationship is broken, the thinner partition, due to its lower mechanical inertia, moves towards the side where the buffer chamber is located at a faster speed to rapidly expand the clearance volume. This solution can effectively optimize the response speed of the clearance volume expansion process, reduce the maximum pressure in the piston chamber of the cylinder block structure when water hammer occurs, and better provide anti-water hammer protection for the cylinder block structure.

[0038] After the fixed relationship is broken, this solution only needs to replace the partition / restore the setting of the partition in the piston chamber. Compared with the direct damage or reduced lifespan of the cylinder block structure caused by water hammer, this solution can effectively shorten the usage cost of the compressor and shorten the downtime. Description of the Drawings

[0039] Figure 1 is a cross-sectional view of a specific embodiment of the anti-water hammer compressor cylinder block structure described in this solution; Figure 2 is Figure 1 a partial enlarged view of part A in Figure 3 is based on the structure shown in Figure 2 and is a schematic structural diagram of a specific embodiment in which the communication channel is formed by using communication holes.

[0040] The reference numerals in the drawings are respectively: 1, intake hole; 2, piston chamber; 3, piston ring assembly; 4, cylinder barrel; 5, partition; 6, communication groove; 7, buffer chamber; 8, exhaust hole; 9, ring body; 10, self-lubricating layer, 11, first sealing ring; 12, snap ring; 13, fixing ring; 14, ring groove; 15, second sealing ring; 16, adjusting screw; 17, spring tube; 18, communication hole; 19, adjusting cone; 20, pressure sensor; 21, end plate; 22, pressure relief hole. Detailed Embodiments

[0041] The present invention will be further described in detail below in conjunction with embodiments, but the present invention is not limited to the following embodiments: Embodiment 1: As Figures 1 to 3 shown, the anti - liquid - hammer compressor cylinder block structure includes a cylinder barrel 4 and a piston ring assembly 3. A piston chamber 2 is provided on the cylinder barrel 4, and further includes a partition 5 fixed inside the piston chamber 2. In the axial direction of the piston chamber 2, the partition 5 isolates the piston chamber 2 into a working chamber and a buffer chamber 7. The piston ring assembly 3 is arranged in the working chamber, and further includes a communication channel provided on the cylinder barrel 4 and / or the partition 5. The communication channel is used to connect the working chambers on both sides of the partition 5 and the buffer chamber 7 to communicate with each other; The partition 5 is configured such that when the pressure difference between the working chamber pressure and the buffer chamber 7 pressure exceeds a set threshold value, under the pressure difference on both sides of the partition 5, the fixed relationship of the partition 5 in the piston chamber 2 is destroyed, and the partition 5 can move towards the side where the buffer chamber 7 is located under this pressure difference.

[0042] This solution aims at the following problem: For the liquid water that has entered the compressor compression chamber (i.e., the above - mentioned working chamber) or the liquid water formed in the compression chamber, in the existing method of using the internal pressure in the compression chamber to push open the pressure - relief channel, the opening of the pressure - relief channel needs to overcome the mechanical inertia of the valve core, spring, etc. During the continuous increase of the pressure in the compression chamber, due to the above - mentioned mechanical inertia, the pressure - relief channel opens untimely. Especially when the liquid water occupies a large volume in the compression chamber, the rapidly increasing internal pressure in the compression chamber will still cause serious liquid - hammer phenomena in the cylinder block structure, resulting in direct damage to the compressor parts or accelerating the fatigue of the parts. The high failure rate of the compressor cylinder block structure seriously affects the orderly and efficient production of wellhead natural gas.

[0043] This solution is a kind of solution that uses the communication effect generated by the communication channel to reduce the pressure difference between the working chambers on both sides of the partition 5 and the buffer chamber 7, so as to form a working chamber pressure boundary with a thinner partition 5. When a liquid - hammer phenomenon occurs in the working chamber, taking advantage of the characteristic that the thinner partition 5 has less mechanical inertia, when the partition 5 moves towards the buffer chamber 7 to expand the volume of the working chamber, the partition 5 can be efficiently accelerated to quickly expand the volume of the working chamber, thereby achieving the purpose of improving the response speed of the inner cavity expansion of the cylinder block structure under the liquid - hammer phenomenon and reducing the negative impact of the liquid - hammer phenomenon on the compressor cylinder block structure.

[0044] Specifically, the maximum pressure that the piston ring assembly 3 can reach when moving in the working chamber and compressing the natural gas at the wellhead is related to the clearance of the working chamber (the clearance itself also serves as a space for accommodating liquid water and directly participates in the protection against liquid hammer damage). However, due to the unstable composition of the well stream in the natural gas at the wellhead, when the volume of liquid water directly entering the cylinder structure and / or the liquid water generated during the compression process exceeds the buffer capacity of the inherent clearance within the cylinder structure, after the liquid water fills too much space in the working chamber, it will cause a serious liquid hammer phenomenon, resulting in direct damage to the cylinder structure or affecting the service life of related parts.

[0045] In this solution, the piston chamber 2 is divided into a working chamber and a buffer chamber 7 by a partition plate 5. At the same time, the piston ring assembly 3 is arranged in the working chamber. In this way, when the cylinder block structure normally compresses the natural gas at the wellhead, the working chamber is the compression chamber, and the partition plate 5 forms the pressure boundary of the compression chamber. When there is no liquid water or only a small amount of liquid water in the working chamber, the clearance in the lower working chamber will not cause the pressure in the working chamber to rise sharply to a large pressure. In this state, the cylinder block structure can operate normally, that is, the phenomenon of water hammer will not occur. However, when there is liquid water in the working chamber that occupies a larger volume of the working chamber during the gas compression process, this liquid water makes the effective clearance of the working chamber smaller. During this process, it will cause the pressure in the working chamber to rise sharply to a large pressure, and the volume of the liquid water is proportional to the pressure rise value and the maximum pressure value. In this solution, on the one hand, it is configured that the fixed relationship of the partition plate 5 in the piston chamber 2 can be broken under the corresponding pressure difference, and the partition plate 5 can move towards the side where the buffer chamber 7 is located under this pressure difference. In this way, when the presence of liquid water in the piston chamber 2 causes the pressure in the working chamber to rise sharply to a large pressure and makes the pressure difference exceed the set threshold (the size of this set threshold needs to be set according to the compressor efficiency, exhaust pressure, etc. For the natural gas compressor at the wellhead, it can be set to 0.When the pressure is between 5 Mpa and 2 Mpa, the partition plate 5 moves towards the buffer cavity 7 due to the destruction of the original fixing relationship, enabling the volume of the working cavity to expand rapidly. This expansion of the volume, relative to the fixed stroke range of the piston ring assembly 3, is equivalent to an increase in the clearance of the working cavity. That is, after the original fixed state of the partition plate 5 is destroyed, the continuous increase in the pressure of the working cavity is curbed. Thus, this solution provides a technical solution for reducing the maximum pressure in the cylinder during liquid hammer by expanding the clearance volume of the cylinder block. On the other hand, to ensure the working efficiency of the compressor, the compressor needs to have a stable compression cavity boundary during normal operation. This solution also includes a communication channel, which is used to achieve that when the pressure in the compression cavity increases, the pressure in the buffer cavity 7 can lag behind the increase in the pressure of the compression cavity. By sacrificing some compression efficiency, this solution utilizes the pressure balancing effect of the communication channel to reduce the pressure difference between the two sides of the partition plate 5 and maintain the necessary pressure boundary of the working cavity. In this way, in terms of the anti-pressure ability requirements of the partition plate 5, by reducing the pressure difference, the partition plate 5 can be made thinner (for example, when there is no communication channel, the partition plate 5 that meets the fatigue and anti-pressure ability requirements needs to use a steel plate of more than 20 mm. After using the communication channel to reduce the pressure difference between the two sides of the partition plate 5, the partition plate 5 that meets the fatigue and anti-pressure ability requirements only needs to use a 5-mm steel plate). When the volume of liquid water in the working cavity is large, resulting in liquid hammer and causing the pressure in the working cavity to rise sharply (depending on the moving speed of the piston and the volume of liquid water in the compression cavity, the pressure in the compression cavity can increase several times faster than the normal pressure growth rate. The throttling effect of the communication channel causes the pressure difference between the two sides of the partition plate 5 to rise sharply. This throttling effect is also used to enable the cylinder block structure to maintain an appropriate compression efficiency). When the pressure difference reaches the set threshold and causes the fixing relationship to be destroyed, the thinner partition plate 5 has lower mechanical inertia. Therefore, the partition plate 5 can move towards the side where the buffer cavity 7 is located at a faster speed under this pressure difference to expand the clearance volume. Compared with the prior art, which relies on the opening of the exhaust valve and the response of the pressure relief channel being affected by mechanical inertia and lagging behind the increase in the internal pressure of the compression cavity, and the cylinder block structure is damaged due to liquid hammer before the corresponding valve plate is fully opened, this solution can effectively optimize the response speed of the clearance volume expansion process, reduce the maximum pressure in the piston cavity 2 of the cylinder block structure during liquid hammer, and better provide anti-liquid hammer protection for the cylinder block structure.

[0046] Meanwhile, as a person skilled in the art, when the fixing relationship of the partition plate 5 in the piston chamber 2 is damaged, the original clearance in the working chamber is damaged, and the original buffer chamber 7 forms an abnormal clearance in the working chamber. To ensure the exhaust pressure and efficiency of the compressor, the compressor needs to be shut down for repair at this time. Specifically, the partition plate 5 is replaced / reset in the piston chamber 2 and then the compressor is restarted. Although this process will also cause compressor failures and necessary downtime, compared with the direct damage or reduced life of the cylinder block structure caused by liquid hammer phenomenon, this solution can effectively reduce the use cost of the compressor and shorten the downtime (when repairing with this solution, only the partition plate 5 needs to be reset, and it is not easy to have major repairs caused by the damage of multiple parts due to liquid hammer).

[0047] Embodiment 2: This embodiment is further refined on the basis of Embodiment 1: A fixing ring 13 is arranged on the outer periphery of the partition plate 5. The fixing ring 13 is an annular structure coaxial with the partition plate 5. A second sealing ring 15 is arranged on the outer side of the fixing ring 13. The second sealing ring 15 is used to realize the axial sealing of the gap between the fixing ring 13 and the wall of the piston chamber 2; It further includes an end plate 21 fixed to the end of the cylinder barrel 4. The fixing ring 13 is connected to the end plate 21 through an adjusting mechanism. The adjusting mechanism is used to adjust the position of the fixing ring 13 on the axis of the piston chamber 2.

[0048] The above solution aims to provide a specific form of fixing the partition plate 5 in the piston chamber 2. Specifically, the fixing ring 13 serves as the outer ring of the outer circumference of the partition plate 5, and the partition plate 5 is fixed to the fixing ring 13. The fixing ring 13 is connected to the end plate 21 through an adjusting mechanism. That is, a technical solution is provided in which the partition plate 5 is connected to the adjusting mechanism through the fixing ring 13, and the specific connection position is located on the end plate 21. In the above structural setting, by using the characteristics that the fixing ring 13 can be processed to be thicker than the partition plate 5 and all positions on the outer circumference of the partition plate 5 are connected to the fixing ring 13, the ability of the partition plate 5 to resist uneven deformation at various positions in the circumferential direction during the working process of the cylinder block structure is strengthened, so as to ensure the compression efficiency and the stability of the clearance of the cylinder block structure; at the same time, this solution completes the connection of the partition plate 5 in the piston chamber 2 based on the fixing ring 13, and for the processing solution that usually uses a casting as the blank of the cylinder barrel 4, it is not necessary to change the existing forming process of the cylinder barrel 4; the above second sealing ring 15 serves as an axial sealing structure, and the communication ability between the working chamber and the piston chamber 2 is only affected by the communication channel. Therefore, this solution can effectively control the communication ability to ensure the compression efficiency and the exhaust pressure of the compressor; the adjusting structure is used to adjust the position of the fixing ring 13 on the axis of the piston chamber 2. When the position of the fixing ring 13 changes, the position of the partition plate 5 changes synchronously. Therefore, the above solution using the partition plate 5 and the communication channel to prevent liquid hammer in the compressor cylinder block can still reasonably adjust the clearance of the working chamber according to production and the characteristics of the compressed medium. Preferably, it is set that the fixing relationship is damaged as the connection relationship between the fixing ring 13 and the partition plate 5 is damaged. The specific solution can be: under the pressure difference, the partition plate 5 is disengaged from the annular groove 14 of the fixing ring 13 by deformation, and the circumferential weld between the partition plate 5 and the fixing ring 13 is damaged, etc. By adopting this solution, when restoring the state of the partition plate 5 in the piston chamber 2, only the reconnection of the fixing ring 13 and the partition plate 5 needs to be completed, and the partition plate 5 is constrained at an appropriate position in the piston chamber 2 through the adjusting mechanism. In such a solution, the original fixing relationship of the partition plate 5 is damaged and the installation of the partition plate 5 on the cylinder block structure is restored, which will not affect the main structure of the cylinder block structure, and has the purpose of reducing the use and maintenance costs of the cylinder block structure.

[0049] Furthermore, the adjusting mechanism includes a plurality of adjusting screws 16. The adjusting screws 16 are annularly distributed relative to the axis of the fixing ring 13. Each adjusting screw 16 passes through the fixing ring 13 and the end plate 21. The adjusting screw 16 is threadedly connected to the end plate 21. The adjusting screw 16 passes through the fixing ring 13 through a through hole provided on the fixing ring 13, and the adjusting screw 16 has a clearance fit with the through hole. A snap ring 12 for restricting the position of the fixing ring 13 in the axial direction of the adjusting screw 16 is arranged on each adjusting screw 16.

[0050] The above provides a specific implementation manner of the adjusting mechanism. In this implementation manner, the clearance fit is used to enable the adjusting screw 16 to rotate independently of the fixed ring 13 in the through hole. By rotating the adjusting screw 16, the position adjustment of the adjusting screw 16 in its axial direction is realized by using the connection thread between the adjusting screw 16 and the end plate 21. The fixed ring 13 moves synchronously with the adjusting screw 16 under the action of the snap ring 12, so as to achieve the purpose of adjusting the position of the partition plate 5 in the piston chamber 2. The method of using multiple adjusting screws 16 and arranging them uniformly around the axis of the fixed ring 13 aims to uniformly support each position in the circumferential direction of the fixed ring 13, so as to avoid axial leakage caused by uneven circumferential pressure when the pressure on both sides of the partition plate 5 fluctuates. In specific implementation, the adjusting screw 16 can be processed with a boss serving as the snap ring 12 on itself, or the snap ring 12 can be set as a shaft retaining ring installed on the adjusting screw 16 through an annular groove.

[0051] Furthermore, each adjusting screw 16 is provided with a bellows 17. The bellows 17 is sleeved outside the adjusting screw 16. One end of the bellows 17 is supported on the fixed ring 13, and the other end is supported on the inner wall of the end plate 21. It also includes a locking nut threadedly connected to the adjusting screw 16 and used to abut against the outer wall of the end plate 21.

[0052] In the above solution, in the state where the position of the fixed ring 13 is restricted by the adjusting screw 16, the bellows 17 is in a compressed state under pressure, and the outer wall of the adjusting screw 16 is in contact with the inside of the bellows 17 to restrict the bellows 17 in a stable position. The bellows 17 is used to achieve: when adjusting the position of the partition plate 5 in the piston chamber 2 by rotating the adjusting screw 16, the bellows 17 provides a thrust for the fixed ring 13 through elastic deformation. In such an application, on the one hand, when the adjusting screws 16 cannot be adjusted synchronously, due to the combined positive influence of the bellows 17 and the second sealing ring 15, the rotational resistance of a single adjusting screw 16 becomes larger. When the adjusting screws 16 are rotated separately by a torque wrench, the influence of the above bellows 17 on the rotational resistance can reduce the compression amount of the second sealing ring 15 on the side where the adjusting screw 16 is located. In such an application, not only can the second sealing ring 15 be protected, but also it is beneficial to maintain the coaxiality between the partition plate 5 and the piston chamber 2. On the other hand, under the thrust of each bellows 17, the fixed ring 13 can be pushed to abut against the snap ring 12 close to the working chamber. In such an application, not only can the bellows 17 restrict the fixed ring 13 in a relatively stable axial position of the adjusting screw 16, reduce the fluctuation of the assembly formed by the fixed ring 13 and the partition plate 5 under the pressure difference on both sides, so as to optimize the working stability of the compressor, but also the clearance size in the clearance fit can be set slightly larger to improve the convenience of adjusting the position of the partition plate 5 in the piston chamber 2.

[0053] Furthermore, an annular groove 14 coaxial with the fixing ring 13 is provided on the inner wall of the fixing ring 13. The edge of the partition plate 5 is embedded in the annular groove 14. A circumferential weld seam is further provided on the side of the partition plate 5 close to the working chamber. The circumferential weld seam realizes the welded connection between the partition plate 5 and the fixing ring 13 and the sealing of the gap between the partition plate 5 and the fixing ring 13.

[0054] In the above solution, the partition plate 5 is clamped inside the fixing ring 13 by using the annular groove 14, so as to utilize the constraints of the front and rear side walls of the annular groove 14 on the front and rear sides of the partition plate 5 to maintain the fixing stability of the partition plate 5 during the operation of the compressor without liquid slugging. The circumferential weld seam is used to seal the corresponding gap to prevent the communication ability between the working chamber and the buffer chamber 7 from being damaged due to the damage of the channels other than the communication channels. The circumferential weld seam is arranged on the side of the partition plate 5 close to the working chamber to achieve: when liquid slugging occurs, the circumferential weld seam is damaged under the tensile force, so that the partition plate 5 can be disengaged from the annular groove 14, achieving the purpose of destroying the fixing relationship. In specific implementation, it is preferably that the fixing ring 13, the partition plate 5 and the circumferential weld seam welding forming material are all stainless steel. In such an application, when the connection position of the circumferential weld seam is damaged under the pressure difference, the content of debris generated and entering the working chamber due to the damage can be effectively reduced, achieving the purpose of reducing the risk of scratching the inner wall of the piston chamber 2 and the piston ring assembly 3 by the debris before the piston ring assembly 3 stops moving. Since the response speed of the above clearance volume expansion process is affected by the weight of the partition plate 5, and at the same time the partition plate 5 also needs to have an appropriate thickness to match the requirements for its compressive capacity and stability, a more optimal application is: the partition plate 5 is set as a laminated structure of a stainless steel plate and a substrate plate. The side of the partition plate 5 close to the working chamber is made of a stainless steel plate, and the side of the partition plate 5 away from the working chamber is a non-stainless steel plate and a substrate plate made of a metal plate. The fixing ring 13 is made of a stainless steel ring, and the circumferential weld seam welding forming material is stainless steel. In such an application, after the circumferential weld seam is damaged under the pressure difference, it not only has the effect of reducing the amount of generated debris (the amount of debris generated after the circumferential weld seam of the welded nodular cast iron plate is damaged is also small, but the nodular cast iron plate is a material that is difficult to weld, and the difficulty of forming the circumferential weld seam is high and the corresponding sealing is difficult to achieve). At the same time, compared with setting the partition plate 5 as a whole stainless steel plate, on the basis of the same compressive capacity and stability characteristics, the mass of the above laminated structure is smaller (taking the substrate as a 45# carbon steel plate, a cast steel plate, a nodular cast iron plate, and the stainless steel plate as a 304 / 316 austenitic stainless steel plate as an example, in order to withstand the same pressure difference and maintain the stability under the alternating pressure difference, the partition plate 5 made of stainless steel needs to be designed thicker, and its material density is also slightly higher than the density of the substrate, so the final weight will be larger than the partition plate 5 of the laminated structure). Therefore, this application can reduce the overall mechanical inertia of the partition plate 5 while reducing debris, which is beneficial to the response speed.

[0055] In a more specific application, the side of the annular groove 14 close to the buffer cavity 7 is provided with a lead-out groove having a frustum structure, and the end with a larger diameter of the frustum structure is close to the working cavity. In this way, when the middle of the partition plate 5 is recessed to a certain extent under the pressure difference on both sides, due to the weakened supporting ability of the back side of the annular groove 14 for the partition plate 5, the partition plate 5 can be more smoothly disengaged from the annular groove 14.

[0056] Embodiment 3: This embodiment is further refined on the basis of Embodiment 1: The communication channel is a communication groove 6 provided on the wall of the piston cavity 2. The communication groove 6 is a strip-shaped groove on the wall. One end of the communication groove 6 is located in the working cavity, and the other end of the communication groove 6 is located in the buffer cavity 7; The number of the communication grooves 6 is multiple, and the communication grooves 6 are arranged at intervals in the circumferential direction of the piston cavity 2.

[0057] The above provides a specific form of setting the communication channel: using the communication groove 6 provided on the wall of the piston cavity 2 and spanning the partition plate 5 as the communication channel. Such a communication channel can be obtained by machining the surface of the wall of the piston cavity 2. It not only has high machining efficiency but also has the characteristic of high machining accuracy of the communication channel; setting the communication groove 6 to be multiple and arranged at intervals in the circumferential direction of the piston cavity 2 aims to achieve: relative to the partition plate 5, the communication groove 6 forms multiple communication channels in the circumferential direction of the partition plate 5. In this way, compared with using a single communication groove 6 (a single communication groove 6 has the same fluid conduction ability as the multiple communication grooves 6 adopted in this solution), during the process of establishing the pressure difference, the more balanced air flow in the circumferential direction of the partition plate 5 can not only reduce the influence of the air flow on the vibration of the partition plate 5, but also, such a method is beneficial to establishing the pressure balance at each position in the cavities of the working cavity (mainly the compressor suction process) and the buffer cavity 7 (mainly the compressor compression process).

[0058] Embodiment 4: This embodiment is further refined on the basis of Embodiment 1: The communication channel is a communication hole 18 provided on the side wall of the piston cavity 2. One end of the communication hole 18 communicates with the exhaust hole 8 of the cylinder barrel 4, and the other end of the communication hole 18 communicates with the buffer cavity 7; It further includes an adjusting cone 19 arranged in the communication hole 18, and the adjusting cone 19 is used to adjust the fluid conduction ability of the communication hole 18.

[0059] The above solution provides another form of connecting channel setting, specifically: the connecting hole 18 realizes the connection between the working chamber and the buffer chamber 7 through the orifices at both ends thereof, and by further including an adjusting cone 19, the problem that the connecting groove 6 cannot adjust the connection ability between the working chamber and the buffer chamber 7 is solved. As described above, while the diaphragm 5 and the buffer chamber 7 are adopted in this solution to achieve the anti-liquid hammer effect, the efficiency of the compressor will be sacrificed. For the well fluid discharge stage where there is no liquid water, little liquid water content or little water vapor content, the possibility of the compressor experiencing liquid hammer phenomenon is relatively low. In such a case, it is not easy for the fixing relationship of the diaphragm 5 to be damaged. Therefore, it can be set to reduce the fluid conduction ability of the connecting hole 18 through the adjusting cone 19 (in such an application, the pressure difference is established faster on both sides of the diaphragm 5, and less liquid content in the working chamber can trigger the damage of the fixing relationship), so as to reduce the gas loss during the pressurization stage of the cylinder block structure and the gas volume injected from the buffer chamber 7 into the working chamber during the suction stage, achieving the purpose of optimizing the compressor efficiency; for the well fluid discharge stage where there is more liquid water content or more water vapor content, the possibility of the compressor experiencing liquid hammer phenomenon increases. In such a case, if the conduction ability of the connecting hole 18 is small, it is easier for the fixing relationship of the diaphragm 5 to be damaged to trigger the anti-liquid hammer damage protection. Therefore, it can be set to increase the fluid conduction ability of the connecting hole 18 through the adjusting cone 19 (in such an application, the pressure difference is established slower on both sides of the diaphragm 5, and more liquid content in the working chamber is required to trigger the damage of the fixing relationship), so as to reduce the compressor efficiency and the exhaust pressure, enhance the adaptability of the cylinder block structure to the liquid content in the working chamber (when liquid hammer occurs, there is a larger liquid content in the working chamber), and reduce the equipment failure rate caused by the damage of the fixing relationship. As a person skilled in the art, the adjusting cone 19 can adopt the structure of a needle valve stem, and the fluid conduction ability of the connecting hole 18 is adjusted by adjusting the insertion depth of the adjusting cone 19 in the connecting hole 18. Setting the orifice on one side of the connecting hole 18 on the exhaust hole 8 aims to achieve: according to the relative positions of the working chamber and the buffer chamber 7, the connecting hole 18 should be set as a bent hole. Therefore, the processing of the connecting hole 18 should preferably adopt the scheme of first setting multiple intersecting process holes and then locally blocking some of the process holes to form the connecting hole 18. When adopting the structure where the process hole is connected to the hole wall at the inlet position of the exhaust hole 8 (it is necessary to avoid the exhaust valve in the exhaust hole 8 in any opening and closing state from affecting the connection between the exhaust hole 8 and the working chamber), based on the basic configuration of the cylinder block structure where the intake hole 1 and the exhaust hole 8 on the cylinder barrel 4 are generally arranged on the side of the cylinder barrel 4, the process hole can be set as a horizontal hole parallel to the axis of the cylinder barrel 4 and a vertical hole along the radial direction of the cylinder barrel 4. The horizontal hole and the vertical hole intersect, and the outer orifices of the horizontal hole and the vertical hole are respectively blocked by plugs to complete the formation of the connecting hole 18.

[0060] Example 5: This embodiment is further refined on the basis of Embodiment 1: It further includes a pressure sensor 20 installed on the cylinder barrel 4, and the pressure sensor 20 is used to monitor the pressure in the working chamber; It further includes a position sensor for monitoring the position of the piston ring assembly 3 in the cylinder barrel 4; It further includes a pressure relief hole 22 provided on the cylinder barrel 4, and the pressure relief hole 22 is configured with an electromagnetic pressure relief valve for controlling the on-off of the pressure relief hole 22; It further includes a control module, and the control module is in signal connection with the pressure sensor 20, the position sensor, and the electromagnetic pressure relief valve. The signal connection is as follows: The control module receives the detection results of the pressure sensor 20 and the position sensor, and transmits an action control signal to the electromagnetic pressure relief valve; The control module is configured to: judge whether the pressure in the current working chamber exceeds the limit according to the monitoring value of the position sensor and the monitoring value of the pressure sensor 20. When the judgment result is that it exceeds the limit, trigger the transmission of an action control signal to the electromagnetic pressure relief valve to open the electromagnetic pressure relief valve.

[0061] As described above, when the anti-liquid hammer protection is triggered by the partition plate 5 and the buffer chamber 7, the original position of the partition plate 5 in the piston chamber 2 is damaged. At this time, the compression efficiency and exhaust pressure of the compressor are greatly affected, and the compressor needs to be restarted after the partition plate 5 is restored. As a pre-protection for the partition plate 5 to trigger the anti-liquid hammer protection, the above provides an electronically controlled pre-protection scheme. Specifically, this scheme utilizes the characteristic that the position of the piston ring assembly 3 in the cylinder barrel 4 is related to the gas compression ratio in the working chamber, and uses the comparison result of the pressure associated with the pressure monitoring value and the position monitoring value to judge whether to trigger the opening of the electromagnetic pressure relief valve. For example, when the liquid water occupies the clearance in the working chamber, resulting in a significant increase in the growth rate of the internal pressure in the working chamber during the compression stroke of the piston ring assembly 3, it can be determined that the internal pressure in the working chamber at the current position of the piston ring assembly 3 exceeds the limit, thereby triggering the opening of the electromagnetic pressure relief valve to release the internal pressure of the working chamber, achieving the above-mentioned pre-protection purpose to reduce the probability of the partition plate 5 triggering the anti-liquid hammer protection.

[0062] It is easy to understand that the above-mentioned electronic control solution and the partition 5 solution are parallel solutions for realizing anti-liquid hammer protection respectively. The electronic control solution is used as the front-stage protection and aims to achieve: in the prior art, the piston ring assembly 3 takes less time to complete one cycle of movement, and the cylinder barrel 4 has the characteristic of unstable temperature. This requires that the relevant sensors not only complete a signal detection quickly, have a high signal pickup frequency, but also have the characteristic that the detection accuracy is less affected by temperature. When using high-precision and high-dynamic sensors and temperature compensation solutions, it can effectively ensure the influence of the detection delay link and detection accuracy on the liquid hammer protection response speed. However, the cost of using sensors is very high, which is not conducive to the economy of the compressor. Therefore, on this basis, when further adopting the partition 5 solution as the post-stage protection, it can effectively reduce the system requirements for the above-mentioned electronic control solution to reduce the setting cost of the electronic control solution, and achieve the effective anti-liquid hammer protection purpose and take into account the economy under the combined action of the above two-stage protections.

[0063] More specifically, it is preferred that the position sensor is a general-precision magnetostrictive displacement sensor, and the pressure sensor 20 is a sensor based on piezoelectric crystals and metal diaphragms. Such sensors have the characteristic of low result response delay, and the electromagnetic pressure relief valve also has the characteristic of rapid action response.

[0064] Regarding the control module, in order to reduce the calculation response delay, the specific logic of the control module can be: calculate the difference or change rate between two adjacent pressure monitoring results, and calculate the difference or change rate between two adjacent position monitoring results, and then use the method of dividing the differences or dividing the change rates (the division is the calculation result of the pressure detection result divided by the calculation result of the position inspection result) to calculate whether the pressure in the current working chamber exceeds the limit. This logic can be implemented by software or by an analog differential circuit (signal type support is required: the analog differential circuit is only applicable to processing analog signals), but when making a specific selection, priority should be given to a solution that takes into account cost control and calculation time consumption.

[0065] Embodiment 6: On the basis of Embodiment 1, this embodiment provides an anti-liquid hammer compressor, including a compressor cylinder block structure, and the compressor cylinder block structure is the compressor cylinder block structure provided in Embodiment 1; The piston ring assembly 3 includes a ring body 9 made of a metal plate, the ring body 9 is connected to the piston rod, and further includes a self-lubricating layer 10 made of a polymer self-lubricating material. The self-lubricating layer 10 is in an annular structure and sleeved on the outer side of the ring body 9. It also includes multiple first sealing rings 11 installed on the outer circumference of the self-lubricating layer 10. The first sealing rings 11 are arranged in sequence in the axial direction of the piston ring assembly 3, and the first sealing rings 11 serve as axial sealing rings between the piston ring assembly 3 and the wall of the working chamber.

[0066] The above-mentioned anti-liquid hammer compressor is a compressor including the compressor cylinder structure. In summary, this solution has the characteristic of effectively optimizing the response speed of the clearance volume expansion process. Furthermore, in view of the sand-producing characteristics of the well fluid, in order to reduce the impact of the relevant abrasive particles in the fluid on the piston ring assembly 3 and the cavity wall of the piston cavity 2, a self-lubricating layer 10 such as a polytetrafluoroethylene material is provided on the outer periphery of the ring body 9, and a first sealing ring 11 is provided on the basis of the self-lubricating layer 10, aiming to achieve: utilizing the characteristic that abrasive particles can be embedded in the polytetrafluoroethylene self-lubricating polymer material, reducing the content of free abrasive particles in the piston cavity 2, so as to reduce the impact of the abrasive particles on the cavity wall of the piston cavity 2.

[0067] Example 7: This embodiment provides a wellhead natural gas compression method based on the embodiment 1. The method is implemented based on the compressor cylinder structure described in the embodiment 1. The method is as follows: The piston ring assembly 3 reciprocates in the working chamber to compress the natural gas at the wellhead; During the process of the piston ring assembly 3 compressing the wellhead natural gas, the communicating passage is used to connect the working chamber and the buffer chamber 7, thereby reducing the pressure difference on both sides of the partition plate 5; When the pressure difference exceeds the set threshold, the fixed relationship of the partition 5 in the piston chamber 2 is destroyed under the pressure difference on both sides of the partition 5, and the partition 5 can move toward the side where the buffer chamber 7 is located under the pressure difference; The compressor cylinder adopts a single-cylinder single-stage compression method that compresses the wellhead natural gas only when the piston ring assembly 3 moves forward or backward, or adopts a single-cylinder two-stage compression method in which an air inlet hole 1 and an air outlet hole 8 are provided at both ends of the cylinder 4, and the wellhead natural gas on one side of the piston ring assembly 3 is compressed when the piston ring assembly 3 moves forward or backward; When the compressor cylinder adopts a single-cylinder single-stage compression mode, the partition plate 5 is arranged on the side of the piston ring assembly 3 away from the piston rod. The piston ring assembly 3 compresses the wellhead natural gas when it moves toward the side where the partition plate 5 is located. The channel opening of the communication channel arranged on the cylinder barrel 4 is located at the end of the working chamber close to the partition plate 5. When the compressor cylinder adopts a single-cylinder two-stage compression method, the partition 5 is arranged on the side of the piston ring assembly 3 away from the piston rod, and the channel opening of the communication channel arranged on the cylinder 4 is located at the end of the working chamber close to the partition 5, and the working chamber is used as: the working chamber between the partition 5 and the piston ring assembly 3 is used as the first-level compression chamber, and the working chamber on the side of the piston ring assembly 3 away from the partition 5 is used as the second-level compression chamber. The second-level compression chamber is used to re-pressurize the wellhead natural gas after the first-level compression chamber is pressurized.

[0068] The above method is a method for realizing wellhead natural gas compression based on the compressor cylinder structure, and further explains the setting method of the partition 5 under the specific compression mode of the compressor cylinder: the buffer chamber 7 is located on the side of the piston ring assembly 3 away from the piston rod, so that after the fixed relationship is destroyed, the conductivity between the formed working chamber and the buffer chamber 7 is used to quickly prevent the internal pressure in the piston chamber 2 from further increasing. Compared with setting the buffer chamber 7 on the side of the cylinder 4 or the end where the piston rod is located, the purpose of optimizing the response speed of the clearance volume expansion process is achieved. The selection of the position of the channel mouth of the above connecting channel enables the piston ring assembly 3 to use the connecting channel to establish a continuously increasing pressure difference on both sides of the partition 5 throughout the compression stroke.

[0069] The above scheme illustrates the functional relationship between the working chambers on both sides of the piston ring assembly 3 at different stages of wellhead natural gas pressurization when the compressor cylinder adopts a single-cylinder two-stage compression method. It is intended to address the following problems: the medium processed by the secondary compression chamber is the medium discharged from the primary compression chamber, stored in the buffer tank, and separated from the water and gas. Therefore, the primary compression chamber is more susceptible to the influence of the water content of the well flow and liquid hammer occurs. In this context, a partition 5 is provided to provide liquid hammer protection for the primary compression chamber. Such a pressurization method not only has the high compression efficiency of the single-cylinder two-stage compression method, but also uses the partition 5 to provide high-response liquid hammer protection for the wellhead natural gas, so that the wellhead natural gas compression not only has the characteristics of high compression efficiency, but also has the characteristics of reliable liquid hammer protection.

[0070] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific embodiments of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, other embodiments derived without departing from the technical solution of the present invention should be included in the scope of protection of the present invention.

Claims

1. Anti-liquid-hammer compressor cylinder block structure, including a cylinder barrel (4) and a piston ring assembly (3), wherein a piston cavity (2) is arranged on the cylinder barrel (4), and it is characterized in that, It further includes a partition plate (5) fixed inside the piston chamber (2). In the axial direction of the piston chamber (2), the partition plate (5) isolates the piston chamber (2) into a working chamber and a buffer chamber (7). The piston ring assembly (3) is arranged in the working chamber. It also includes a communication channel provided on the cylinder barrel (4) and / or the partition plate (5), and the communication channel is used to realize the communication between the working chambers on both sides of the partition plate (5) and the buffer chamber (7). The partition plate (5) is configured such that when the pressure difference between the working chamber pressure and the buffer chamber (7) pressure exceeds a set threshold, under the pressure difference on both sides of the partition plate (5), the fixing relationship of the partition plate (5) in the piston chamber (2) is damaged, and the partition plate (5) can move towards the side where the buffer chamber (7) is located under this pressure difference.

2. The anti - water - hammer compressor cylinder block structure according to claim 1, characterized in that, A fixing ring (13) is arranged on the outer periphery of the partition plate (5). The fixing ring (13) is an annular structure coaxial with the partition plate (5). A second sealing ring (15) is arranged on the outer side of the fixing ring (13), and the second sealing ring (15) is used to realize the axial sealing of the gap between the fixing ring (13) and the wall of the piston chamber (2). It further includes an end plate (21) fixed to the end of the cylinder barrel (4). The fixing ring (13) is connected to the end plate (21) through an adjusting mechanism, and the adjusting mechanism is used to adjust the position of the fixing ring (13) on the axis of the piston chamber (2).

3. The anti - liquid - hammer compressor cylinder block structure according to claim 2, characterized in that, The adjusting mechanism includes a plurality of adjusting screws (16). The adjusting screws (16) are annularly and evenly distributed relative to the axis of the fixing ring (13). Each adjusting screw (16) passes through the fixing ring (13) and the end plate (21). The adjusting screw (16) is threadedly connected to the end plate (21). The adjusting screw (16) passes through the fixing ring (13) through a through hole provided on the fixing ring (13), and the adjusting screw (16) has a clearance fit with the through hole. A snap ring (12) for restricting the position of the fixing ring (13) in the axial direction of the adjusting screw (16) is arranged on each adjusting screw (16).

4. The anti - water - hammer compressor cylinder block structure according to claim 3, wherein, Each adjusting screw (16) is provided with a spring tube (17). The spring tube (17) is sleeved on the outer side of the adjusting screw (16). One end of the spring tube (17) is supported on the fixing ring (13), and the other end is supported on the inner wall of the end plate (21). It further includes a locking nut threadedly connected to the adjusting screw (16) and used to abut against the outer wall of the end plate (21).

5. The anti - liquid - hammer compressor cylinder block structure according to any one of claims 2 to 4, characterized in that, A ring groove (14) coaxial with the fixing ring (13) is arranged on the inner wall of the fixing ring (13). The edge of the partition plate (5) is embedded in the ring groove (14). A circumferential weld is also arranged on the side of the partition plate (5) close to the working chamber, and the circumferential weld realizes the welded connection between the partition plate (5) and the fixing ring (13) and the sealing of the gap between the partition plate (5) and the fixing ring (13).

6. The anti - liquid - hammer compressor cylinder block structure according to any one of claims 1 to 4, characterized in that, The communication channel is a communication groove (6) provided on the wall of the piston chamber (2). The communication groove (6) is a strip-shaped groove on the wall. One end of the communication groove (6) is located in the working chamber, and the other end of the communication groove (6) is located in the buffer chamber (7). The number of the communication grooves (6) is multiple, and the communication grooves (6) are arranged at intervals in the circumferential direction of the piston chamber (2).

7. The anti - water - hammer compressor cylinder block structure according to any one of claims 1 to 4, characterized in that, The communication channel is a communication hole (18) provided on the side wall of the piston chamber (2). One end of the communication hole (18) communicates with the exhaust hole (8) of the cylinder barrel (4), and the other end of the communication hole (18) communicates with the buffer chamber (7). It further includes an adjusting cone (19) disposed in the communication hole (18), and the adjusting cone (19) is used to adjust the fluid conduction ability of the communication hole (18).

8. The anti - water - hammer compressor cylinder block structure according to claim 1, characterized in that, It further includes a pressure sensor (20) installed on the cylinder barrel (4), and the pressure sensor (20) is used to monitor the pressure in the working chamber. It further includes a position sensor for monitoring the position of the piston ring assembly (3) in the cylinder barrel (4). It further includes a pressure relief hole (22) provided on the cylinder barrel (4), and the pressure relief hole (22) is configured with an electromagnetic pressure relief valve for controlling the on / off of the pressure relief hole (22). It further includes a control module, and the control module is in signal connection with the pressure sensor (20), the position sensor, and the electromagnetic pressure relief valve. The signal connection is that the control module receives the detection results of the pressure sensor (20) and the position sensor, and transmits an action control signal to the electromagnetic pressure relief valve. The control module is configured to: judge whether the pressure in the current working chamber exceeds the limit according to the monitoring value of the position sensor and the monitoring value of the pressure sensor (20). When the judgment result is that it exceeds the limit, trigger the transmission of an action control signal to open the electromagnetic pressure relief valve to the electromagnetic pressure relief valve.

9. Anti-surge compressor, including a compressor cylinder block structure, characterized in that, The compressor cylinder block structure is the compressor cylinder block structure provided in any one of claims 1 to 8. The piston ring assembly (3) includes a ring body (9) which is a metal plate. The ring body (9) is connected to the piston rod. It further includes a self-lubricating layer (10) made of a polymer self-lubricating material. The self-lubricating layer (10) is in an annular structure and sleeved on the outside of the ring body (9). It further includes a plurality of first sealing rings (11) installed on the outer periphery of the self-lubricating layer (10). The first sealing rings (11) are arranged in sequence in the axial direction of the piston ring assembly (3), and the first sealing ring (11) serves as an axial sealing ring between the piston ring assembly (3) and the wall of the working chamber.

10. A method for compressing natural gas at the wellhead, characterized in that, This method is implemented based on the compressor cylinder block structure described in any one of claims 1 to 8. This method is as follows: The piston ring assembly (3) reciprocates in the working chamber to compress the natural gas at the wellhead. During the process of the piston ring assembly (3) compressing the natural gas at the wellhead, the communication function of the working chamber and the buffer chamber (7) played by the communication channel is utilized to reduce the pressure difference between the two sides of the partition plate (5). When the pressure difference exceeds the set threshold, under the pressure difference on both sides of the partition plate (5), the fixed relationship of the partition plate (5) in the piston chamber (2) is damaged, and it can move towards the side where the buffer chamber (7) is located under this pressure difference. The compressor cylinder block adopts a single-cylinder single-stage compression method that only compresses the natural gas at the wellhead when the piston ring assembly (3) moves forward or backward, or adopts a single-cylinder double-stage compression method that has intake holes (1) and exhaust holes (8) provided at both ends of the cylinder barrel (4), and compresses the natural gas at the wellhead on one side of the piston ring assembly (3) when the piston ring assembly (3) moves forward and backward. When the compressor cylinder block adopts the single-cylinder single-stage compression mode, the partition plate (5) is arranged on the side of the piston ring assembly (3) away from the piston rod. When the piston ring assembly (3) moves towards the side where the partition plate (5) is located, the wellhead natural gas is compressed. The orifice of the communication channel arranged on the cylinder barrel (4) is located at one end of the working chamber close to the partition plate (5). When the compressor cylinder block adopts the single-cylinder double-stage compression mode, the partition plate (5) is arranged on the side of the piston ring assembly (3) away from the piston rod. The orifice of the communication channel arranged on the cylinder barrel (4) is located at one end of the working chamber close to the partition plate (5), and the working chamber is used as follows: the working chamber between the partition plate (5) and the piston ring assembly (3) is used as the first-stage compression chamber, and the working chamber on the side of the piston ring assembly (3) away from the partition plate (5) is used as the second-stage compression chamber. The second-stage compression chamber is used to re-pressurize the wellhead natural gas after being pressurized by the first-stage compression chamber.

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