An adjustable clearance reciprocating compressor and its control method

Abstract

This invention discloses an adjustable clearance reciprocating compressor and its control method, belonging to the field of compressor technology. The reciprocating compressor includes a cylinder body with a piston chamber, a main piston in the piston chamber, and an intermediate piston in the piston chamber. The intermediate piston and the main piston form a compression chamber. It also includes an adjustment mechanism, which includes a partition plate and a metal diaphragm. The intermediate piston and the partition plate form a first chamber, the partition plate and the metal diaphragm form a second chamber, and the metal diaphragm and an end plate form a third chamber. The partition plate has a channel connecting the first and second chambers, and the channel is equipped with the control mechanism. The third chamber is equipped with an oil supply system. The control method is based on the reciprocating compressor. This solution not only enables clearance adjustment of the reciprocating compressor but also features reliable compressor sealing performance and optimized stress on the metal diaphragm to extend its service life.

Description

Technical Field

[0001] This invention relates to the field of compressor technology, specifically to an adjustable clearance reciprocating compressor and its control method. Background Technology

[0002] Hydrogen and natural gas are two important energy gases. To achieve product gas production and meet other requirements such as transportation processes, hydrogen compressors and natural gas compressors are widely used specialty gas compressors. For reciprocating compressors, adjustable clearance reciprocating compressors are preferred. Typically, due to hydrogen's high adiabatic index, significant temperature rise during compression, significantly increased hydrogen embrittlement of materials, and susceptibility to seal failure, using an adjustable clearance reciprocating compressor to pressurize it, compared to adjusting motor rotation parameters or cooling schemes, can effectively reduce exhaust temperature by increasing the cylinder clearance and lowering the compression ratio. For hydrogen refueling station applications, the pressure range of the hydrogen compressor outlet storage tank... The pressure fluctuations are significant (e.g., from 10MPa to 45MPa), resulting in a large range of changes in the compressor's compression ratio during the pressurization process of the gas tank. When facing motor overload and moving parts operating beyond design stress under high pressure ratio conditions, increasing the cylinder clearance can effectively solve the related problems under high pressure ratio conditions. The low viscosity and high diffusivity of hydrogen make it easy to leak through tiny gaps. At the same time, the significant temperature rise during the compression process will also cause increased piston wear. When the compressor pressure curve is distorted and vibration is caused by gas leakage at the piston ring position, increasing the cylinder clearance can effectively reduce the peak pressure and the gradient value of the cylinder pressure, thereby suppressing wear and vibration deterioration, and allowing the compressor to continue to operate normally for a longer period of time. Generally, compared to hydrogen, natural gas has a more complex and variable composition. During compression, the composition of natural gas can lead to excessively high compression temperatures, as well as issues such as coking and liquid separation within the cylinder. Using a reciprocating compressor with adjustable clearance can not only balance compressor efficiency and operational sustainability by employing a reasonable clearance size for different gas compositions, but also, when used in gas stations, can adjust the clearance to adapt the gas output to the load demand, avoiding frequent compressor start-ups and shutdowns.

[0003] Traditionally, widely used adjustable clearance piston compressors typically employ the following method: a threaded rod is threaded onto the end cover of the cylinder, and an intermediate piston is positioned at the end of the threaded rod that extends into the cylinder. The threaded rod is rotated via a handwheel or other drive mechanism, causing the intermediate piston to move forward or backward within the cylinder, thereby adjusting the compressor clearance. A search reveals existing publicly available technologies of this type, such as the patent titled "Natural Gas Compressor Clearance Adjuster," patent application number CN201821122622.1.

[0004] However, hydrogen and natural gas are both hazardous gas media. From a safety perspective, the intermediate piston with piston rings still has the potential for gas leakage. Furthermore, the threaded rod and end cap form a threaded pair, which is the leakage point for gas leakage from the compressor to the outside. Even if a packing seal structure with relatively reliable sealing performance and low threaded rod driving resistance (self-lubricating material) is used for this sealing point, the sealing structure formed at this location is a dynamic seal structure, which still has a large possibility of leakage. This implementation method is not the preferred method for compressors that compress hydrogen and natural gas and have high exhaust pressure.

[0005] The prior art also includes a technical solution with patent application number CN202110031319.0 and invention titled "Compressor Clearance Adjustment System". This technical solution is based on hydraulic adjustment of compressor clearance. Compared with using a threaded rod to achieve clearance adjustment, this solution only requires configuring a static sealing structure on the compressor cylinder structure. Therefore, from the perspective of preventing gas leakage, although this clearance adjustment method is structurally complex, the sealing effect is more reliable.

[0006] Piston compressors play an indispensable role in the production of pressurized hydrogen and natural gas. Further optimization of related technologies will undoubtedly further promote the development of special gas pressurization technology. Summary of the Invention

[0007] To address the aforementioned issues in optimizing reciprocating compressors, this invention provides an adjustable clearance reciprocating compressor and its control method. The structural design provided by this solution not only enables clearance adjustment of the reciprocating compressor but also features reliable compressor sealing performance and optimized stress on the metal diaphragm to extend its service life.

[0008] The objective of this invention is mainly achieved through the following technical solution: an adjustable clearance piston compressor, comprising a cylinder body, wherein a piston chamber is provided in the cylinder body, a main piston for pressurizing gas is provided in the piston chamber, and an intermediate piston is provided in the piston chamber, wherein the intermediate piston and the main piston form a compression chamber: the intermediate piston serves as the boundary of the compression chamber, and an adjustment mechanism for adjusting the position of the intermediate piston in the axial direction of the piston chamber is also provided. The adjustment mechanism comprises a partition plate and a metal diaphragm, wherein the main piston, intermediate piston, partition plate, metal diaphragm, and end plate are arranged sequentially in the axial direction of the piston chamber.

[0009] The intermediate piston and the partition plate form a first cavity, the partition plate and the metal diaphragm form a second cavity, and the metal diaphragm and the end plate form a third cavity.

[0010] The partition is provided with a channel connecting the first cavity and the second cavity, and the channel is equipped with a control mechanism to control the opening and closing of the channel;

[0011] The third cavity is equipped with an oil supply system for injecting and discharging hydraulic oil into the third cavity.

[0012] In this solution, the main piston is used to reciprocate in the piston chamber under the action of the drive unit to realize the intake and compression of gas in the compression chamber. The drive unit includes, but is not limited to, an electric drive unit and a hydraulic drive unit. The intermediate piston is used to form the boundary of the compression chamber. When the intermediate piston moves closer to the main piston, the clearance of the reciprocating compressor decreases. When the intermediate piston moves away from the main piston, the clearance of the reciprocating compressor increases. The adjustment mechanism is used to adjust the position of the intermediate piston relative to the main piston. Unlike the prior art, this solution provides a reciprocating compressor with a specific adjustment mechanism implementation. Specifically, the partition divides the cavity between the intermediate piston and the diaphragm into a first cavity and a second cavity, and the metal diaphragm divides the cavity between the partition and the end plate into a second cavity and a third cavity. In practical application, hydraulic oil is injected into the first cavity, the second cavity, and the third cavity. When the channel is configured to allow the first and second cavities to be connected via the control mechanism, the third cavity, under the action of the oil supply system, experiences an increase in injection pressure. This causes the metal diaphragm to deform towards the side where the second cavity is located. At this time, the metal diaphragm squeezes the hydraulic oil in the second cavity, causing the hydraulic oil in the second cavity to be injected into the first cavity through the channel. The internal pressure in the first cavity increases, thereby squeezing the intermediate piston towards the side where the main piston is located to achieve clearance reduction adjustment. After the intermediate piston is adjusted to the required position, the... The control mechanism adjusts the channel to prevent hydraulic oil from flowing from the first chamber to the second chamber. To achieve increased clearance adjustment, when the control mechanism adjusts the channel to allow the first and second chambers to communicate, the third chamber, under the action of the oil supply system, experiences a decrease in discharge pressure, causing the metal diaphragm to deform towards the side where the third chamber is located. At this time, the volume of the second chamber increases, and the hydraulic oil pressure inside decreases, allowing hydraulic oil from the first chamber to be injected into the second chamber through the channel. In this state, the intermediate piston can be displaced away from the main piston under the action of the compression chamber air pressure and / or the reset device to achieve increased clearance adjustment. After adjusting the intermediate piston to the desired position, the control mechanism adjusts the channel to prevent hydraulic oil from flowing from the first chamber to the second chamber.

[0013] The above adjustment mechanism differs from existing technologies in that:

[0014] First, this solution achieves intermediate piston position adjustment. From a necessity perspective, only an oil supply system is needed for the third chamber. Compared to the existing threaded rod drive solution, no dynamic sealing points are added to the cylinder block or end plate. Therefore, the structural design proposed in this solution can effectively ensure the sealing performance of the gas processed by the compressor, fundamentally guaranteeing the compressor's sealing safety for hazardous gases (such as hydrogen). Even if gas leaks into the first chamber at the intermediate piston position, the baffle and metal diaphragm serve as physical barriers to further gas leakage. Therefore, this solution has ideal safety when processing hazardous gases.

[0015] Secondly, this solution uses hydraulic oil to transmit the force to the intermediate piston. A partition is placed between the intermediate piston and the metal diaphragm, and a channel and control mechanism are configured on the partition. The control mechanism controls the channel cutoff. Thus, after clearance adjustment, the partition can be configured to completely isolate the first and second chambers, sealing the hydraulic oil in the first chamber within it. In this state, the intermediate piston experiences alternating forces due to the periodic pressure changes within the compression chamber during compressor operation. The hydraulic oil in the first chamber supports the intermediate piston, and the partition acts as a rigid barrier, ensuring that the alternating forces only affect the internal pressure of the first chamber. Therefore, for the metal diaphragm, the partition separates the metal diaphragm from the alternating forces... Force isolation prevents the metal diaphragm from bearing alternating stress caused by the pulsating gas pressure in the compression chamber during the periodic pressure changes within the compression chamber, which can lead to fatigue failure. (In the prior art, the alternating stress is transmitted to the metal diaphragm, causing high-cycle fatigue that is synchronized with the compressor's operating frequency, and has a higher stress amplitude during the compression and exhaust phases.) Therefore, this solution changes the existing high-cycle fatigue to low-cycle fatigue from the perspective of the metal diaphragm's stress. This solution has the characteristic of optimizing the stress on the metal diaphragm to improve its service life.

[0016] Secondly, compared to the intermediate piston bearing alternating forces acting on the metal diaphragm, this solution uses a baffle to isolate these forces from the metal diaphragm. This not only effectively protects the metal diaphragm, but also ensures that the system stiffness (bulk elastic modulus) of the oil supply system has no impact on stabilizing the position of the intermediate piston during compressor operation. Therefore, this solution can effectively reduce the design requirements of the oil supply system during use and prevent the oil supply system from being damaged under the influence of the alternating forces.

[0017] Finally, on the one hand, this solution uses a metal diaphragm to isolate the third chamber from the second chamber, while allowing the second chamber to communicate with the first chamber. In practical application, this provides a structural basis for using the first hydraulic oil in the third chamber and the second hydraulic oil in both the second and first chambers. Specifically, the first hydraulic oil uses a high bulk modulus hydraulic control oil, such as common servo hydraulic oil or aviation hydraulic oil, to ensure rapid and accurate system response when the oil supply system completes relevant adjustments. The second hydraulic oil uses mature PAG compressor lubricating oil, which is perfectly compatible with the compressed gas. PAG compressor lubricating oil generally has a lower bulk modulus than hydraulic control oil, but even if it leaks through the intermediate piston into the compression chamber, it can still serve the lubrication of the main piston / piston chamber and is compatible with the compressed gas, cylinder material, and main piston material, preventing hydraulic oil contamination of the compressed gas and air passages. Simultaneously, because the first... One cavity is located near and supports the intermediate piston. Compared to the volumes of the first cavity, second cavity, third cavity, and related oil circuits in the oil supply system, the first cavity has a smaller volume. Therefore, even if PAG compressor lubricating oil with a low bulk modulus is used inside, the smaller volume of PAG compressor lubricating oil can still maintain the positional stability of the intermediate piston in the piston cavity. On the other hand, by adopting the layout of the intermediate piston and metal diaphragm, even if hydraulic oil in the third cavity leaks into the second cavity due to the rupture of the metal diaphragm (which is relatively fragile) (as described in the one-way valve assembly application scheme below), since the intermediate piston acts as an axial seal on the path from the first cavity to the compression cavity, this scheme can effectively avoid contamination of the compressed gas and subsequent gas circuit caused by direct leakage of hydraulic oil into the compression cavity compared to using a metal diaphragm to directly provide a boundary for the compression cavity.

[0018] A further technical solution for the aforementioned adjustable clearance reciprocating compressor:

[0019] The channel includes a first connecting hole and a second connecting hole that both penetrate the partition plate;

[0020] The control mechanism includes a one-way valve assembly and a solenoid valve assembly;

[0021] The one-way valve assembly is disposed on the first communication hole. The one-way valve assembly allows hydraulic oil to be injected from the second chamber into the first chamber and prevents hydraulic oil from being injected from the first chamber into the second chamber.

[0022] The second connecting hole is equipped with a solenoid valve assembly, which is a normally closed valve. When the solenoid valve assembly is in the closed state, it cuts off the second connecting hole. When the solenoid valve assembly is in the open state, the second connecting hole enables communication between the first cavity and the second cavity.

[0023] The above provides an implementation method for a channel and a control mechanism. In this solution, the channel includes a first connecting hole and a second connecting hole, and the control mechanism includes a one-way valve assembly and a solenoid valve assembly that act on the first connecting hole and the second connecting hole, respectively. The one-way valve assembly is configured to allow hydraulic oil to be injected from the second cavity into the first cavity under the action of pressure difference. The solenoid valve assembly is configured as a normally closed valve, which cuts off the second connecting hole in the closed state and allows communication between the first cavity and the second cavity through the second connecting hole in the controlled open state. The above implementation method can be specifically applied as follows: when When the compressor clearance needs to be reduced, the solenoid valve assembly remains closed, and the oil supply system injects oil into the third chamber. Hydraulic oil in the second chamber, under pressure, enters the first chamber through the one-way valve assembly, pushing the intermediate piston towards the main piston. When the compressor clearance needs to be increased, the solenoid valve assembly is controlled to open, and the third chamber discharges oil through the oil supply system. The second connecting hole allows hydraulic oil in the first chamber to enter the second chamber under the pressure of the intermediate piston, enabling the intermediate piston to move away from the main piston under the pressure of the compression chamber and / or the action of the reset device. The plug direction shifts, and this solution aims to address the following issues: Based on the first connecting hole and the one-way valve assembly, it enables active oil discharge from the second chamber to the first chamber under pressure differential. During compressor operation, hydraulic oil leakage from the first chamber to the compression chamber, which is prone to occur at the intermediate piston position, occurs when the pressure in the first chamber drops due to reduced oil volume caused by hydraulic oil leakage. Even if the oil supply system does not intervene in the third chamber (during the non-clearance adjustment phase, the pressure in the third chamber is locked: the oil supply system is in a pressure-holding state to maintain the pressure in the third chamber, so that...) (Given a stable morphology of the metal diaphragm), the hydraulic oil in the second chamber can automatically replenish the first chamber through the one-way valve assembly under pressure differential. Simultaneously, when the oil volume in the second chamber decreases and pressure drops, the pressure on the side of the metal diaphragm closest to the second chamber decreases. At the same time, the hydraulic oil pressure in the third chamber is locked. The metal diaphragm deforms slightly towards the side containing the second chamber under the pressure differential, continuing to push the hydraulic oil in the second chamber into the first chamber. This achieves the purpose of maintaining the stability of the intermediate piston position, maintaining clearance stability, and extending the maintenance cycle under this fault condition. In other words, by adopting the above channel configuration and control mechanism configuration, without active control, the oil volume and pressure in the first chamber can be replenished and restored within a certain range after hydraulic oil leakage occurs, thereby providing active protection for the positional stability of the intermediate piston and reducing drift caused by hydraulic oil leakage.As those skilled in the art would know, if the oil supply system does not actively intervene in the pressure in the third chamber, the amount of oil replenished by this first chamber replenishment method is relatively limited. Under such application, the deformation of the metal diaphragm is limited. Therefore, this solution can only deal with the slight leakage of hydraulic oil occurring at the intermediate piston position. When there is a large leakage, if it is necessary to maintain the stability of the intermediate piston position, the oil supply system needs to act on the third chamber and deform the metal diaphragm towards the second chamber to maintain the stability of the intermediate piston position.

[0024] A more specific solution is to attach a sensor to the metal diaphragm to monitor its deformation. The sensor's monitoring results indicate the amount of deformation of the metal diaphragm. Based on the change in deformation, the cumulative leakage at the intermediate piston position can be indirectly determined. When the cumulative leakage exceeds a set threshold, an alarm is triggered or the oil supply system pressurizes the third chamber. For intermediate piston position drift caused by leakage at the intermediate piston position, other solutions include: installing an airbag accumulator in the first or second chamber. When the external pressure of the airbag accumulator decreases, it expands in volume to occupy more space, thereby providing additional compensation oil to the first chamber or maintaining the pressure in the first chamber. Since the airbag accumulator will reduce the system stiffness of the corresponding chamber, when selecting the airbag accumulator, an airbag accumulator with appropriate stiffness should be used, taking into account the resistance of the intermediate piston movement, to avoid instability of the intermediate piston position under alternating pressure differentials in the piston chamber.

[0025] It also includes a reset device that provides a continuous reset force to the intermediate piston, the continuous reset force being directed toward the partition.

[0026] The above provides a technical solution for adjusting the position of the intermediate piston based on a reset device during the clearance increase adjustment process. Specifically, under the action of the continuous reset force provided by the reset device, when the through hole connects the first and second chambers, the intermediate piston moves away from the main piston under the action of the reset force. Although the intermediate piston can move away from the main piston under the air pressure of the compression chamber, this solution has the following characteristics: When it is necessary to increase the clearance, the solenoid valve assembly needs to be in the open state, and the pressure of the compression chamber can only push the intermediate piston away from the main piston during the compression stroke of the main piston. When the timing of the control mechanism opening the channel is during the compressor's suction stroke, if it only relies on the pressure of the compression chamber on the intermediate piston, the intermediate piston will not respond during the suction stroke and will have to wait for the next compression stroke to trigger the intermediate piston to move. Therefore, relying solely on the pressure of the compression chamber on the intermediate piston will result in no action of the intermediate piston during the suction stroke. The pressure exerted by the compression chamber on the intermediate piston to adjust its position presents problems such as delayed response of the intermediate piston and high requirements for the control timing / logic of the control mechanism. With the reset device configured, on the one hand, the reset device provides real-time and reliable force to the intermediate piston, so the displacement of the intermediate piston no longer depends on the pressure exerted by the compression chamber. Therefore, when a larger clearance is needed, it is only necessary to control the channel to allow hydraulic oil from the first chamber to enter the second chamber, ensuring timely and reliable operation of the intermediate piston without requiring precise and complex control timing / logic for the control mechanism. On the other hand, the continuous reset force is equivalent to a pulling force acting on the intermediate piston and towards the partition. Thus, during the process of pushing the intermediate piston away from the partition, the first chamber has a higher oil pressure compared to when no reset device is used. Therefore, this solution is advantageous in suppressing the possibility of gas from the compression chamber entering the first chamber through the sealed position of the intermediate piston and causing gas backflow.

[0027] The reset device includes a tension spring disposed in the first cavity, one end of which is fixed to the intermediate piston and the other end of which is fixed to the partition plate.

[0028] The above provides a specific implementation of a reset device. For those skilled in the art, the reset device can be implemented using elastic elements (coil springs, disc springs, air springs) or other methods that provide continuous reset force (such as magnetic drive). However, in practical applications, if magnetic drive is used, a relatively complex structure is required, and the magnitude of the magnetic force is significantly affected by temperature. Therefore, the above implementation uses a simple structure that stores force as the intermediate piston moves away from the partition. More specifically, regarding the implementation of the tension spring, the tension spring can use any of the above elastic elements. If an air spring is used, temperature has a significant impact on the force exerted by the reset device on the intermediate piston. If a disc spring is used, its deformation range is small, and its stiffness changes significantly with deformation. Therefore, preferably, the tension spring uses a coil spring with a large deformation range, stable elastic force with deformation, and good adaptability to temperature changes, such as a stainless steel coil spring or a special alloy coil spring.

[0029] It also includes a cylinder liner embedded in the cylinder block, wherein the piston chamber is formed on the cylinder liner: the piston chamber is the central hole of the cylinder liner;

[0030] The cylinder liner is a two-section structure consisting of an inner sleeve and an outer sleeve. Relative to the end plate, the inner sleeve is a cylinder liner that extends into the cylinder body, and the outer sleeve is a cylinder liner whose inner end is connected to the outer end of the inner sleeve and whose outer end is supported by the end plate.

[0031] The main piston and intermediate piston are both fitted into the inner sleeve, the partition is formed on the outer sleeve, the control mechanism is fixed on the partition, and the edge of the metal diaphragm is clamped between the outer sleeve and the end plate.

[0032] The above provides a technical solution that uses an embedded cylinder liner in the cylinder block to provide the piston cavity wall, thereby improving the wear resistance of the piston cavity wall, improving the compatibility of the piston cavity wall with the gas being processed, and reducing the post-wear treatment cost of the piston cavity wall while controlling material costs. The cylinder liner adopts a two-section structure consisting of an inner sleeve and an outer sleeve, and uses the above-described fit between the parts. This design aims to facilitate the assembly of internal cylinder parts, prevent gas leakage through the gap between the cylinder body and the cylinder liner, and simplify the complexity of the internal cylinder structure. Specifically, for the assembly of internal cylinder parts, firstly, the inner sleeve is installed from the end plate side of the cylinder body. Then, the main piston is embedded into the inner sleeve. For the implementation where a tension spring is provided between the intermediate piston and the partition plate, after the intermediate piston and partition plate are connected outside the cylinder body, the intermediate piston is embedded into the inner sleeve and the outer sleeve is connected to the inner sleeve from the end plate side of the cylinder body. For the implementation where the intermediate piston and partition plate are relatively independent, the intermediate piston is first embedded into the inner sleeve, and then the outer sleeve is connected to the inner sleeve. Then, a metal diaphragm and an end plate are sequentially stacked on the outer end of the outer sleeve. Finally, the final assembly is completed by the connecting bolts between the end plate and the cylinder body. The fact that both the main piston and the intermediate piston fit into the inner sleeve is intended to prevent leakage through the gap. The partition plate is formed on the outer sleeve, which is intended to simplify the complexity of the internal cylinder structure. More specifically, axial sealing rings are installed in the gaps between the cylinder body and the cylinder sleeve on both sides of the mating position between the inner sleeve and the outer sleeve. These sealing rings are used to prevent hydraulic oil leakage in the first cavity. Sealing gaskets are also installed between the cylinder body and the end plate, between the metal diaphragm and the outer sleeve, and between the metal diaphragm and the end plate. These sealing gaskets are used to prevent hydraulic oil leakage in the second cavity and the third cavity.

[0033] It also includes multiple through holes provided on the cylinder body, which serve as communication channels between the first cavity and the outside of the cylinder body;

[0034] Among the multiple through holes, including through holes with their inner openings located on the bottom side of the first cavity and through holes with their inner openings located on the top side of the first cavity, the number of through holes with their openings located on the top side of the first cavity is greater than or equal to 2.

[0035] The inner orifice is located in the through hole on the bottom side of the first cavity and includes an oil injection hole for injecting oil into the first cavity. The inner orifice is located in the through hole on the top side of the first cavity and includes an exhaust hole for venting gas from the first cavity during the oil injection process. Both the oil injection hole and the exhaust hole are equipped with plugs.

[0036] It also includes a sensor mounted on the cylinder body through a through hole located on the top side of the first cavity, the sensor being configured to detect whether the top side region of the first cavity contains gas.

[0037] In the above scheme, the through hole serves as a multifunctional hole and is specifically used as follows: hydraulic oil is injected into the first cavity through the oil injection hole, and air in the first cavity is discharged through the vent hole during the oil injection process. After the first cavity is completely filled with hydraulic oil, the oil injection hole and the vent hole are sealed by the plug. The orifice is located in the through hole on the top side of the first cavity, including the mounting hole for installing the sensor. After the sensor is installed, it is used to realize that the gas detection sensor can directly monitor whether gas has entered the first cavity due to gas backflow, so as to perform timely maintenance on the compressor when a gas backflow fault is detected. As skilled technicians, considering the deformation of the metal diaphragm and its requirements for the volume of the second cavity, as well as the clearance adjustment range and the capacity of the tension spring and its requirements for the volume of the first cavity, the volume of the first cavity should be designed to be larger than that of the second cavity. Furthermore, since gas backflow from the compression chamber directly enters the first cavity, configuring a through hole in the first cavity is of great significance from both an oil injection and gas monitoring perspective. As for the second cavity, since its volume is relatively small and there is no need to monitor for gas backflow, and its hydraulic oil filling can be achieved by installing the metal diaphragm in the oil reservoir and introducing the hydraulic oil from the first cavity into the second cavity through the aforementioned channel, thus replacing the gas in the second cavity. Therefore, configuring a through hole in the second cavity is not necessary. Those skilled in the art can choose to configure a through hole in the second cavity as an oil injection hole or an exhaust hole to facilitate later compressor maintenance. To simplify the processing of components such as the cylinder block, a through hole can also be configured only in the first cavity.

[0038] It also includes a monitoring module, which is used to monitor the exhaust temperature of the reciprocating compressor and / or the vibration of the cylinder during the gas compression process;

[0039] It also includes a control module, which is signal-connected to the monitoring module. The control module is configured to acquire the exhaust temperature and / or vibration signal, and determine whether the exhaust temperature exceeds a set temperature threshold and / or whether the cylinder vibration exceeds a set abnormal vibration threshold.

[0040] The control module is signal-connected to the control mechanism and the oil supply system. The control module is configured to: when the reciprocating compressor exhaust temperature is abnormal and / or the vibration is abnormal according to the set temperature threshold and / or the set vibration abnormality threshold, control the control mechanism and the oil supply system to operate. The oil supply system operates by: discharging oil from the third chamber to reduce the internal pressure of the third chamber. The control mechanism operates by: keeping the channel in a state that connects the first chamber and the second chamber, and after the intermediate piston moves to increase the clearance of the reciprocating compressor, keeping the channel in a state that cuts off the first chamber and the second chamber.

[0041] The above provides a monitoring module and a control module that, when abnormal compressor exhaust temperature or vibration is detected, uses closed-loop control to increase clearance adjustment based on perception, judgment, and execution. In other words, this solution provides a proactive approach to address abnormal exhaust temperature and / or vibration faults by actively adjusting the clearance. For those skilled in the art, the core concept of this solution lies in the implementation of the adjustment mechanism. For a compressor including this adjustment mechanism, when the monitoring parameters of the monitoring module and the fault judgment parameters of the control module include, for example, the current of the main piston drive motor, and it is determined that this current is abnormally increased, in order to protect the compressor and ensure uninterrupted gas compression, the control module controls the control mechanism and the oil supply system to reduce the current of the drive motor by increasing the compressor clearance. Such closed-loop control to achieve proactive adjustment and protection should also be considered equivalent to the above concept. Furthermore, to meet the needs of compressor efficiency, when the control module determines that the exhaust temperature and cylinder vibration have a safe margin based on the signal acquisition results of the monitoring module, the compressor clearance can also be reduced through closed-loop control. To better protect the compressor, reducing the compressor clearance can also be accomplished through manual intervention.

[0042] It also includes a first hydraulic oil that fills and fills the third cavity; and a second hydraulic oil that fills and fills the first cavity and the second cavity, wherein the first hydraulic oil is hydraulic control oil and the second hydraulic oil is compressor lubricating oil, and the bulk elastic modulus of the hydraulic control oil is greater than that of the compressor lubricating oil.

[0043] As described above, the above solution provides a technical solution that enables the system to respond quickly and accurately when the oil supply system completes relevant adjustments, and avoids hydraulic oil contamination of the compressed gas and gas path, by distinguishing the hydraulic oil in different cavities. Preferably, the first hydraulic oil is servo hydraulic oil, and when the compressed gas of this reciprocating compressor is hydrogen or natural gas, the second hydraulic oil is compressor lubricating oil suitable for lubricating the main piston of the reciprocating compressor.

[0044] This solution also relates to a control method for a reciprocating compressor as described in any of the above embodiments, the control method comprising the following steps:

[0045] Real-time monitoring of the exhaust temperature of the reciprocating compressor and / or the vibration of the cylinder during gas compression;

[0046] Based on real-time monitoring results, determine whether the reciprocating compressor exhibits a preset abnormal discharge temperature and / or abnormal vibration.

[0047] When it is determined that an abnormally high exhaust temperature and / or abnormal vibration have occurred, the pressure of the hydraulic oil in the third chamber is reduced through the oil supply system, and the first chamber and the second chamber are connected through the control mechanism and based on the channel.

[0048] Under the action of the gas pressure in the compression chamber and / or the action of the reset device, the intermediate piston moves along the piston chamber axis and toward the side where the partition is located to increase the clearance of the reciprocating compressor. The reset device is used to provide a continuous reset force to the intermediate piston, and the continuous reset force is directed toward the partition.

[0049] After the clearance increase adjustment is completed, the channel is cut off by the control mechanism to achieve isolation between the first cavity and the second cavity.

[0050] It is easy to understand that the above control method is a control method for the above reciprocating compressor to deal with abnormal exhaust temperature and abnormal vibration. This control method is highly related to the hydrogen and natural gas compression process. As someone skilled in the art, the reciprocating compressor provided by this solution can also be adapted to clearance adjustment in other scenarios, such as only serving the adjustment of compressor discharge volume and compressor discharge pressure.

[0051] A further technical solution for the control method of the reciprocating compressor is as follows:

[0052] The method for determining whether a reciprocating compressor has abnormal vibration is as follows: perform anomaly analysis on the vibration signal and distinguish the fault type;

[0053] in:

[0054] If a first-type vibration abnormality characteristic corresponding to a liquid slugging fault in the compression chamber is identified, it is determined that a liquid slugging abnormality has occurred.

[0055] If a second type of abnormal vibration feature corresponding to leakage in the main piston is identified, it is determined that a leakage abnormality has occurred.

[0056] One method to increase the clearance of a reciprocating compressor is as follows:

[0057] When a liquid slugging abnormality occurs, the position of the intermediate piston is adjusted by the first preset displacement.

[0058] When only a leakage anomaly occurs, the intermediate piston position is adjusted by the second preset displacement amount;

[0059] The first preset displacement is greater than the second preset displacement.

[0060] The above provides a specific technical solution based on vibration anomaly judgment, classification of anomaly causes, and matching of specific clearance adjustment amounts according to specific classifications. Specifically: when a liquid slugging anomaly is judged to occur, compared to a leakage anomaly, a method based on a larger intermediate piston displacement adjustment is provided to improve the compressor's operational safety when liquid slugging occurs by using a larger clearance adjustment amount; when a leakage anomaly is judged to occur, compared to a liquid slugging anomaly, a method based on a smaller intermediate piston displacement adjustment is provided to ensure the compressor's operating efficiency by using a smaller clearance adjustment amount.

[0061] In practice, the vibration anomaly can be judged based solely on the relatively simple cylinder vibration amplitude. To improve the accuracy and reliability of fault type differentiation, the following scheme can be adopted to differentiate vibration anomalies:

[0062] In one specific embodiment, the vibration signal of the cylinder is continuously acquired and the waveform analysis of the vibration signal is performed;

[0063] If an impact feature is detected in the waveform analysis results and the number of impact features exceeds a set number within a set operating cycle, it is determined that the piston compressor is experiencing abnormal vibration.

[0064] The impact features include a first impact feature corresponding to a liquid hammer anomaly and a second impact feature corresponding to a leakage anomaly.

[0065] The first impact characteristic is a vibration signal with a maximum amplitude greater than a first preset threshold and an amplitude rise rate greater than a second preset threshold;

[0066] The second impact characteristic is the main piston leakage fault signal in the vibration signal spectrum, specifically: a vibration signal that occurs periodically in sync with the working frequency of the piston compressor, and whose maximum amplitude is greater than a third preset threshold and whose amplitude rise rate is greater than a fourth preset threshold.

[0067] The first preset threshold is greater than the third preset threshold, and the second preset threshold is greater than the fourth preset threshold.

[0068] In one specific embodiment, the vibration signal of the cylinder is continuously acquired and the vibration signal is subjected to spectrum analysis;

[0069] If a feature corresponding to a specific fault is identified in the spectrum analysis results, and the feature continues or repeats within a set operating cycle, it is determined that the reciprocating compressor has a corresponding vibration abnormality.

[0070] The features include a first spectral feature corresponding to a liquid hammer anomaly and a second spectral feature corresponding to a leakage anomaly;

[0071] The first spectral feature is that a significant increase in energy occurs in a wide frequency band on the vibration signal spectrum: within multiple discrete frequency bands or continuous high-frequency bands, spectral components with amplitudes exceeding a first preset spectral threshold are detected.

[0072] The second spectral feature is that, on the vibration signal spectrum, at integer multiples (dominants) of the compressor's operating frequency, discrete spectral peaks with amplitudes exceeding a second preset spectral threshold appear, and the energy of these spectral peaks continues to occur over multiple consecutive operating cycles.

[0073] Wherein, the first preset spectrum threshold is greater than the second preset spectrum threshold.

[0074] Similar to the above-mentioned use of vibration signal waveforms, the fault type is distinguished by identifying spectral characteristics, and then the intermediate piston position is adjusted to differentiate the displacement: after the clearance adjustment, the clearance under liquid slugging abnormality is greater than the clearance under leakage abnormality, so that the clearance adjustment can simultaneously ensure the compressor compression efficiency and efficiently eliminate abnormal vibration.

[0075] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0076] The structural design proposed in this solution can effectively ensure the sealing of the gas processed by the compressor, fundamentally guaranteeing the sealing safety of the compressor for high-risk gases (such as hydrogen).

[0077] This solution uses hydraulic oil to transmit the force of the intermediate piston. A partition is set between the intermediate piston and the metal diaphragm, and a channel and control mechanism are configured on the partition. After the clearance adjustment is completed, the partition can be configured to completely isolate the first chamber from the second chamber, so that the hydraulic oil in the first chamber is sealed in the first chamber. In this state, the partition acts as a rigid barrier, so that the alternating force only affects the internal pressure of the first chamber. This avoids the metal diaphragm from bearing the alternating stress caused by the pressure pulsation of the gas in the compression chamber during the periodic change of the internal pressure of the compression chamber, which would cause fatigue failure of the metal diaphragm. From the perspective of the stress on the metal diaphragm, this solution has the feature of optimizing the stress on the metal diaphragm to benefit the service life of the metal diaphragm.

[0078] This solution uses a partition to isolate the alternating force from the metal diaphragm, which not only effectively protects the metal diaphragm, but also effectively reduces the design requirements of the oil supply system and prevents the oil supply system from being damaged under the influence of the alternating force.

[0079] This solution employs a metal diaphragm to isolate the third chamber from the second chamber, while allowing the second chamber to communicate with the first chamber. By using differentiated hydraulic oil, the oil supply system can achieve rapid and accurate system response when making relevant adjustments. The hydraulic oil released into the compression chamber can avoid contaminating the compressed gas and air passages. It can also maintain the positional stability of the intermediate piston in the piston chamber and effectively prevent hydraulic oil from leaking directly into the compression chamber, thus avoiding contamination of the compressed gas and subsequent air passages. Attached Figure Description

[0080] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0081] Figure 1 This is a partial cross-sectional view of the cylinder portion in a specific embodiment of an adjustable clearance piston compressor according to the present invention.

[0082] Figure 2 This is a side view of the outer casing in a specific embodiment of an adjustable clearance piston compressor according to the present invention.

[0083] The labels in the diagram represent:

[0084] 1. Cylinder block, 2. Piston chamber, 3. Main piston, 4. Compression chamber, 5. Intermediate piston, 6. First chamber, 7. Tension spring, 8. Solenoid valve assembly, 9. Baffle plate, 10. Second chamber, 11. Check valve assembly, 12. Metal diaphragm, 13. Third chamber, 14. End plate, 15. Cylinder liner, 16. First connecting hole, 17. Second connecting hole, 18. Inner sleeve, 19. Outer sleeve, 20. Through hole. Detailed Implementation

[0085] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0086] Example 1:

[0087] like Figure 1 and Figure 2As shown, this embodiment of the invention provides an adjustable clearance reciprocating compressor, including a cylinder 1, a piston chamber 2 in the cylinder 1, a main piston 3 for pressurizing gas in the piston chamber 2, and an intermediate piston 5 disposed in the piston chamber 2. The intermediate piston 5 and the main piston 3 form a compression chamber 4. The intermediate piston 5 serves as the boundary of the compression chamber 4. The invention also includes an adjustment mechanism for adjusting the position of the intermediate piston 5 in the axial direction of the piston chamber 2. The adjustment mechanism includes a partition 9 and a metal diaphragm 12. In the axial direction of the piston chamber 2, the main piston 3, the intermediate piston 5, the partition 9, the metal diaphragm 12, and the end plate 14 are arranged sequentially.

[0088] The intermediate piston 5 and the partition plate 9 form a first cavity 6, the partition plate 9 and the metal diaphragm 12 form a second cavity 10, and the metal diaphragm 12 and the end plate 14 form a third cavity 13.

[0089] The partition 9 is provided with a channel connecting the first cavity 6 and the second cavity 10, and the channel is equipped with a control mechanism to realize the channel opening and closing control;

[0090] The third cavity 13 is equipped with an oil supply system for injecting and discharging hydraulic oil into the third cavity 13.

[0091] In this solution, the main piston 3 is used to reciprocate in the piston chamber 2 under the action of the drive unit to realize the intake and compression of gas in the compression chamber 4. The drive unit includes, but is not limited to, an electric drive unit and a hydraulic drive unit. The intermediate piston 5 is used to form the boundary of the compression chamber 4. When the intermediate piston 5 moves closer to the main piston 3, the clearance of the reciprocating compressor becomes smaller. When the intermediate piston 5 moves away from the main piston 3, the clearance of the reciprocating compressor increases. The adjustment mechanism is used to adjust the position of the intermediate piston 5 relative to the main piston 3. Unlike the prior art, this solution provides a reciprocating compressor with a specific adjustment mechanism implementation. Specifically, the partition 9 divides the cavity between the intermediate piston 5 and the diaphragm into a first cavity 6 and a second cavity 10. The metal diaphragm 12 divides the cavity between the partition 9 and the end plate 14 into a second cavity 10 and a third cavity 13. In practical application, hydraulic oil is injected into the first cavity 6, the second cavity 10, and the third cavity 13. When the channel is configured to allow the first cavity 6 and the second cavity 10 to be connected via the control mechanism, the third cavity 13, under the action of the oil supply system, experiences an increase in injection pressure. This causes the metal diaphragm 12 to deform towards the side where the second cavity 10 is located. At this time, the metal diaphragm 12 squeezes the hydraulic oil in the second cavity 10, causing the hydraulic oil in the second cavity 10 to be injected into the first cavity 6 through the channel. The internal pressure in the first cavity 6 increases, thereby squeezing the intermediate piston 5 towards the side where the main piston 3 is located, achieving clearance reduction adjustment, and adjusting the intermediate piston 5 to the required position. After the position is adjusted, the channel is adjusted by the control mechanism to prevent the hydraulic oil in the first cavity 6 from flowing into the second cavity 10. To achieve the increased clearance adjustment, when the channel is adjusted by the control mechanism to achieve the state of conduction between the first cavity 6 and the second cavity 10, the third cavity 13, under the action of the oil supply system, deforms the metal diaphragm 12 towards the side where the third cavity 13 is located after the oil discharge pressure decreases. At this time, the volume of the second cavity 10 increases, and the hydraulic oil pressure inside it decreases, so that the hydraulic oil in the first cavity 6 can be injected into the second cavity 10 through the channel. In this state, the intermediate piston 5 can be displaced away from the main piston 3 under the action of the air pressure in the compression chamber 4 and / or the reset device to achieve the increased clearance adjustment. After the intermediate piston 5 is adjusted to the required position, the channel is adjusted by the control mechanism to prevent the hydraulic oil in the first cavity 6 from flowing into the second cavity 10.

[0092] The above adjustment mechanism differs from existing technologies in that:

[0093] First, this solution allows for the adjustment of the position of the intermediate piston 5. From a necessity perspective, only an oil supply system is needed for the third chamber 13. Compared to the existing threaded rod drive solution, no dynamic sealing points are added to the cylinder 1 or end plate 14. Therefore, the structural design proposed in this solution can effectively ensure the sealing performance of the gas processed by the compressor, fundamentally ensuring the sealing safety of the compressor for high-risk gases (such as hydrogen). Even if gas leaks into the first chamber 6 at the position of the intermediate piston 5, the partition plate 9 and the metal diaphragm 12 serve as physical barriers to further gas leakage. Therefore, this solution has ideal safety when processing high-risk gases.

[0094] Secondly, this solution uses hydraulic oil to transmit force to the intermediate piston 5, and a partition 9 is set between the intermediate piston 5 and the metal diaphragm 12. A channel and control mechanism are configured on the partition 9, and the channel is cut off through the control mechanism. Thus, after clearance adjustment, the partition 9 can be configured to completely isolate the first chamber 6 from the second chamber 10, sealing the hydraulic oil in the first chamber 6. In this state, the intermediate piston 5, subjected to alternating forces due to the periodic pressure changes in the compression chamber 4 during compressor operation, is supported by the hydraulic oil in the first chamber 6, and the partition 9 acts as a rigid barrier, ensuring that the alternating forces only affect the internal pressure of the first chamber 6. Therefore, for the metal diaphragm 12, since the partition 9 separates the metal diaphragm 12 from the alternating forces... By isolating the variable force, this solution avoids the metal diaphragm 12 from bearing the alternating stress caused by the gas pressure pulsation in the compression chamber 4 during the periodic pressure changes within the compression chamber 4, which could lead to fatigue failure of the metal diaphragm 12. (In the prior art, the alternating stress is transmitted to the metal diaphragm 12, causing high-cycle fatigue that is synchronized with the compressor's operating frequency, and has a higher stress amplitude during the compression and exhaust phase.) Therefore, this solution changes the existing high-cycle fatigue to low-cycle fatigue from the perspective of the stress on the metal diaphragm 12. This solution has the characteristic of optimizing the stress on the metal diaphragm 12 to benefit its service life.

[0095] Secondly, compared to the intermediate piston 5 bearing alternating forces acting on the metal diaphragm 12, this solution uses a partition 9 to isolate the forces from the metal diaphragm 12. This not only effectively protects the metal diaphragm 12, but also ensures that the system stiffness (bulk elastic modulus) of the oil supply system has no effect on stabilizing the position of the intermediate piston 5 during compressor operation. Therefore, this solution can effectively reduce the design requirements of the oil supply system during use and prevent the oil supply system from being damaged under the influence of the alternating forces.

[0096] Finally, on the one hand, this solution uses a metal diaphragm 12 to isolate the third chamber 13 from the second chamber 10, while allowing the second chamber 10 to communicate with the first chamber 6. In practical application, this provides a structural basis for using the first hydraulic oil in the third chamber 13 and the second hydraulic oil in the second chamber 10 and the first chamber 6. Specifically, the first hydraulic oil uses a hydraulic control oil with a high volumetric elastic modulus, such as common servo hydraulic oil or aviation hydraulic oil, to ensure a fast and accurate system response when the oil supply system completes relevant adjustments. The second hydraulic oil uses a mature PAG compressor lubricating oil that is perfectly compatible with the compressed gas. PAG compressor lubricating oil generally has a lower volumetric elastic modulus than hydraulic control oil, but even if the PAG compressor lubricating oil leaks through the intermediate piston 5 into the compression chamber 4, it can still serve the lubrication of the main piston 3 / piston chamber 2 and is compatible with the compressed gas, cylinder material, and main piston 3 material, preventing hydraulic oil from contaminating the compressed gas and the air passage. At the same time, since the first chamber 6 is close to... The intermediate piston 5 and the cavity that supports it have a smaller volume compared to the volumes of the first cavity 6, the second cavity 10, the third cavity 13, and the related oil circuits in the oil supply system. Therefore, even if PAG compressor lubricating oil with a small bulk modulus is installed inside it, the smaller volume of PAG compressor lubricating oil can still maintain the positional stability of the intermediate piston 5 in the piston cavity 2. On the other hand, by adopting the layout of the intermediate piston 5 and the metal diaphragm 12, even if the hydraulic oil in the third cavity 13 leaks into the second cavity 10 due to the rupture of the metal diaphragm 12 (the metal diaphragm 12 is relatively fragile) (in the case of the one-way valve assembly 11 below), since the intermediate piston 5 acts as an axial seal on the path from the first cavity 6 to the compression cavity 4, this solution can effectively avoid the contamination of the compressed gas and subsequent gas circuit caused by the direct leakage of hydraulic oil into the compression cavity 4 compared to using the metal diaphragm 12 to directly provide the boundary for the compression cavity 4.

[0097] Example 2:

[0098] This embodiment is a further refinement of embodiment 1:

[0099] The channel includes a first connecting hole 16 and a second connecting hole 17 that both penetrate the partition 9;

[0100] The control mechanism includes a one-way valve assembly 11 and a solenoid valve assembly 8;

[0101] The one-way valve assembly 11 is disposed on the first connecting hole 16. The one-way valve assembly 11 allows hydraulic oil to be injected from the second chamber 10 into the first chamber 6 and prevents hydraulic oil from being injected from the first chamber 6 into the second chamber 10.

[0102] A solenoid valve assembly 8 is configured on the second connecting hole 17. The solenoid valve assembly 8 is a normally closed valve. When the solenoid valve assembly 8 is in the closed state, it cuts off the second connecting hole 17. When the solenoid valve assembly 8 is in the open state, the second connecting hole 17 enables the first cavity 6 to communicate with the second cavity 10.

[0103] The above provides an implementation of a channel and a control mechanism. In this solution, the channel includes a first connecting hole 16 and a second connecting hole 17. The control mechanism includes a one-way valve assembly 11 and a solenoid valve assembly 8 that act on the first connecting hole 16 and the second connecting hole 17, respectively. The one-way valve assembly 11 is configured to allow hydraulic oil to be injected from the second chamber 10 into the first chamber 6 under the action of pressure difference. The solenoid valve assembly 8 is configured as a normally closed valve. In the closed state, it cuts off the second connecting hole 17. In the controlled open state, it connects the first chamber 6 and the second chamber 10 through the second connecting hole 17. The above implementation can be specifically applied. When it is necessary to reduce the compressor clearance, the solenoid valve assembly 8 remains closed, and the oil supply system injects oil into the third chamber 13. Under pressure, the hydraulic oil in the second chamber 10 enters the first chamber 6 through the one-way valve assembly 11, pushing the intermediate piston 5 towards the main piston 3. When it is necessary to increase the compressor clearance, the solenoid valve assembly 8 is controlled to open, and the third chamber 13 discharges oil through the oil supply system. The second connecting hole 17 allows the hydraulic oil in the first chamber 6 to enter the second chamber 10 under the pressure of the intermediate piston 5, so that the intermediate piston 5 can move away from the main piston 3 under the pressure of the compression chamber 4 and / or the reset device. The main piston 3 moves in the direction of the following solution: Based on the first connecting hole 16 and the one-way valve assembly 11, the second chamber 10 actively discharges oil to the first chamber 6 under pressure difference. During compressor operation, for hydraulic oil leakage from the first chamber 6 to the compression chamber 4, which is prone to occur at the position of the intermediate piston 5, when the pressure of the first chamber 6 drops due to the reduction of oil volume caused by hydraulic oil leakage, even if the oil supply system does not intervene in the third chamber 13 (during the non-clearance adjustment phase, the pressure in the third chamber 13 is locked: the oil supply system is in a pressure-holding state to maintain the pressure in the third chamber 13, so that the gold (Since the diaphragm 12 has a stable shape), the hydraulic oil in the second chamber 10 can automatically replenish the first chamber 6 through the one-way valve assembly 11 under pressure differential. Simultaneously, when the oil volume in the second chamber 10 decreases and the pressure drops, the pressure on the side of the metal diaphragm 12 closest to the second chamber 10 decreases. At the same time, the hydraulic oil pressure in the third chamber 13 is locked. The metal diaphragm 12 deforms slightly towards the side where the second chamber 10 is located under the pressure differential, continuing to push the hydraulic oil in the second chamber 10 into the first chamber 6. This achieves the purpose of maintaining the stable position of the intermediate piston 5, maintaining a stable clearance, and extending the maintenance cycle under this fault. In other words, by adopting the above channel configuration and control mechanism configuration, without active control, the oil volume and pressure in the first chamber 6 can be replenished and restored within a certain range after hydraulic oil leakage occurs, thereby providing active protection for the positional stability of the intermediate piston 5 and reducing the drift of the intermediate piston 5 due to hydraulic oil leakage.As those skilled in the art know, if the oil supply system does not actively intervene in the pressure in the third chamber 13, the amount of oil replenished by the first chamber 6 in this oil replenishment method is relatively limited. Under such application, the deformation of the metal diaphragm 12 is limited. Therefore, this solution can only deal with the small leakage of hydraulic oil occurring at the position of the intermediate piston 5. When there is a large leakage, if it is necessary to maintain the stability of the position of the intermediate piston 5, the oil supply system needs to act on the third chamber 13 and deform the metal diaphragm 12 towards the second chamber 10 to maintain the stability of the position of the intermediate piston 5.

[0104] A more specific solution is to attach a sensor to the metal diaphragm 12 to monitor its deformation. The sensor's monitoring results indicate the amount of deformation of the metal diaphragm 12. Based on the change in the amount of deformation, the cumulative leakage at the position of the intermediate piston 5 can be indirectly determined. When the cumulative leakage exceeds a set threshold, an alarm is triggered or the oil supply system pressurizes the third chamber 13. For the position drift of the intermediate piston 5 caused by leakage at the position of the intermediate piston 5, other solutions include: setting an airbag accumulator in the first chamber 6 or the second chamber 10. When the external pressure of the airbag accumulator decreases, it occupies more space through volume expansion, thereby providing additional compensation oil to the first chamber 6 or maintaining the pressure in the first chamber 6. Since the airbag accumulator will reduce the system stiffness of the corresponding chamber, when selecting the airbag accumulator, an airbag accumulator with appropriate stiffness should be used, taking into account the movement resistance of the intermediate piston 5, to avoid the intermediate piston 5 becoming unstable under the alternating pressure difference of the piston chamber 2.

[0105] Example 3:

[0106] This embodiment is a further refinement of embodiment 1:

[0107] It also includes a reset device that provides a continuous reset force to the intermediate piston 5, the continuous reset force being directed toward the partition 9.

[0108] The above provides a technical solution for adjusting the position of the intermediate piston 5 based on a reset device during the clearance increase adjustment process. Specifically, under the action of the continuous reset force provided by the reset device, when the through hole connects the first cavity 6 and the second cavity 10, the intermediate piston 5 moves away from the main piston 3 under the action of the reset force. Although the intermediate piston 5 can move away from the main piston 3 under the air pressure of the compression chamber 4, this solution has the following characteristics compared to the intermediate piston 5 only being able to move away from the main piston 3 under the air pressure of the compression chamber 4: when it is necessary to increase the clearance, the solenoid valve assembly 8 needs to be in the open state, and only during the compression stroke of the main piston 3, the pressure of the compression chamber 4 can push the intermediate piston 5 to move away from the main piston 3. When the timing of the control mechanism opening the channel is during the compressor's suction stroke, if it only relies on the pressure of the compression chamber 4 on the intermediate piston 5, the intermediate piston 5 will not respond during the suction stroke and must wait for the next compression stroke to trigger the intermediate piston 5 to produce a displacement action. Therefore, relying solely on The position adjustment of the intermediate piston 5 is achieved by the pressure of the compression chamber 4 on the intermediate piston 5. However, this method suffers from problems such as delayed response of the intermediate piston 5 and high requirements for the control timing / logic of the control mechanism. After configuring the reset device, on the one hand, the reset device provides real-time and reliable force to the intermediate piston 5, and the displacement of the intermediate piston 5 no longer depends on the pressure of the compression chamber 4 on the intermediate piston 5. Therefore, when it is necessary to increase the clearance, it is only necessary to control the channel to allow the hydraulic oil in the first chamber 6 to enter the second chamber 10, ensuring that the intermediate piston 5 moves promptly and reliably. It does not require the control mechanism to provide precise and complex control timing / logic. On the other hand, the above continuous reset force is equivalent to a pulling force acting on the intermediate piston 5 and towards the partition 9. Thus, during the process of pushing the intermediate piston 5 to move away from the partition 9, the first chamber 6 has a higher oil pressure compared to the case without the reset device. Therefore, this solution is beneficial in suppressing the possible backflow of gas from the compression chamber 4 into the first chamber 6 through the sealed position of the intermediate piston 5.

[0109] Example 4:

[0110] This embodiment is a further refinement of embodiment 3:

[0111] The reset device includes a tension spring 7 disposed in the first cavity 6, one end of the tension spring 7 being fixed to the intermediate piston 5, and the other end of the tension spring 7 being fixed to the partition plate 9.

[0112] The above provides a specific implementation of a reset device. For those skilled in the art, the reset device can be implemented using elastic elements (coil springs, disc springs, air springs) or other methods that provide continuous reset force (such as magnetic drive). However, in practical applications, if magnetic drive is used, a relatively complex structure is required, and the magnitude of the magnetic force is significantly affected by temperature. Therefore, the above implementation uses a simple structure that stores force as the intermediate piston 5 moves away from the partition 9. More specifically, regarding the implementation of the tension spring 7, the tension spring 7 can use any of the above elastic elements. If an air spring is used, temperature has a significant impact on the force exerted by the reset device on the intermediate piston 5. If a disc spring is used, its deformation range is small, and its stiffness changes significantly with deformation. Therefore, preferably, the tension spring uses a coil spring with a large deformation range, stable elastic force with deformation, and good adaptability to temperature changes, such as a stainless steel coil spring or a special alloy coil spring.

[0113] Example 5:

[0114] This embodiment is a further refinement of embodiment 1:

[0115] It also includes a cylinder liner 15 embedded in the cylinder body 1, and the piston chamber 2 is formed on the cylinder liner 15: the piston chamber 2 is the center hole of the cylinder liner 15;

[0116] The cylinder liner 15 is a two-section structure including an inner sleeve 18 and an outer sleeve 19. Relative to the end plate 14, the inner sleeve 18 is a cylinder liner 15 that extends into the cylinder body 1, and the outer sleeve 19 is a cylinder liner 15 whose inner end is connected to the outer end of the inner sleeve 18 and whose outer end is supported by the end plate 14.

[0117] The main piston 3 and the intermediate piston 5 are both fitted in the inner sleeve 18. The partition 9 is formed on the outer sleeve 19. The control mechanism is fixed on the partition 9. The edge of the metal diaphragm 12 is clamped between the outer sleeve 19 and the end plate 14.

[0118] The above provides a technical solution that uses an embedded cylinder liner 15 in the cylinder body 1 to provide the piston chamber 2 wall, thereby improving the wear resistance of the piston chamber 2 wall, improving the compatibility of the piston chamber 2 wall with the gas being processed, and reducing the post-wear treatment cost of the piston chamber 2 wall while controlling material costs. The cylinder liner 15 is a two-section structure including an inner sleeve 18 and an outer sleeve 19, and the above-described fit between the parts is used to facilitate the assembly of internal parts of the cylinder body 1, prevent gas leakage from the gap between the cylinder body 1 and the cylinder liner 15, and simplify the complexity of the internal structure of the cylinder body 1. Specifically, for the assembly of internal parts of the cylinder body 1, firstly, the inner sleeve 18 is installed from the end plate 14 side of the cylinder body 1, and then the main piston 3 is embedded into the inner sleeve 18. Then, for the implementation of a tension spring 7 between the intermediate piston 5 and the partition plate 9, after the intermediate piston 5 and the partition plate 9 are connected outside the cylinder body 1, the tension spring 7 is installed from the end plate 14 of the cylinder body 1. On the side, the intermediate piston 5 is embedded in the inner sleeve 18 and the outer sleeve 19 is connected to the inner sleeve 18. For the relatively independent implementation of the intermediate piston 5 and the partition plate 9, the intermediate piston 5 is first embedded in the inner sleeve 18, and then the outer sleeve 19 is connected to the inner sleeve 18. Then, the metal diaphragm 12 and the end plate 14 are stacked on the outer end of the outer sleeve 19 in sequence. Finally, the final assembly is completed by the connecting bolts between the end plate 14 and the cylinder body 1. The main piston 3 and the intermediate piston 5 are both fitted in the inner sleeve 18 to avoid leakage through the gap. The partition plate 9 is formed on the outer sleeve 19 to simplify the internal structure complexity of the cylinder body 1. More specifically, axial sealing rings are provided in the gaps between the cylinder body 1 and the cylinder sleeve 15 on both sides of the mating position of the inner sleeve 18 and the outer sleeve 19. These sealing rings are used to prevent hydraulic oil leakage in the first cavity 6. Sealing gaskets are also provided between the cylinder body 1 and the end plate 14, between the metal diaphragm 12 and the outer sleeve 19, and between the metal diaphragm 12 and the end plate 14. These sealing gaskets are used to prevent hydraulic oil leakage in the second cavity 10 and the third cavity 13.

[0119] Example 6:

[0120] This embodiment is a further refinement of embodiment 1:

[0121] It also includes a plurality of through holes 20 provided on the cylinder body 1, the through holes 20 serving as communication channels between the first cavity 6 and the outside of the cylinder body 1;

[0122] Among the multiple through holes 20, there are through holes 20 with their inner openings located on the bottom side of the first cavity 6 and through holes 20 with their inner openings located on the top side of the first cavity 6. The number of through holes 20 with their openings located on the top side of the first cavity 6 is greater than or equal to 2.

[0123] The inner orifice is located in the through hole 20 on the bottom side of the first cavity 6, including an oil injection hole for injecting oil into the first cavity 6. The inner orifice is located in the through hole 20 on the top side of the first cavity 6, including an exhaust hole for venting gas from the first cavity 6 during the oil injection process. Both the oil injection hole and the exhaust hole are equipped with plugs.

[0124] It also includes a sensor mounted on the cylinder 1 through a through hole 20 located on the top side of the first cavity 6, the sensor being configured to detect whether the top side region of the first cavity 6 contains gas.

[0125] In the above scheme, the through hole 20 serves as a multi-functional hole and is specifically used as follows: hydraulic oil is injected into the first cavity 6 through the oil injection hole, and air in the first cavity 6 is discharged through the vent hole during the oil injection process. After the first cavity 6 is completely filled with hydraulic oil, the oil injection hole and the vent hole are sealed by the plug. The orifice is located in the through hole 20 on the top side of the first cavity 6, including the mounting hole for installing the sensor. After the sensor is installed, it is used to realize that the gas detection sensor can directly monitor whether gas enters the first cavity 6 due to gas backflow, so as to perform timely maintenance on the compressor when a gas backflow fault is detected. As skilled technicians, considering the deformation of the metal diaphragm 12 and its impact on the volume requirements of the second cavity 10, as well as the clearance adjustment range and the capacity requirements of the tension spring 7 on the volume requirements of the first cavity 6, the volume of the first cavity 6 should be designed to be larger than that of the second cavity 10. Furthermore, to prevent backflow of gas from the compression chamber 4, the gas directly enters the first cavity 6. Therefore, from both an oil injection and gas monitoring perspective, configuring a through hole 20 in the first cavity 6 is of great significance. As for the second cavity 10, since its volume is relatively small and there is no need to monitor whether any backflow occurs within it... Gas backflow can be achieved by installing a metal diaphragm 12 in the oil reservoir and introducing the hydraulic oil in the first cavity 6 into the second cavity 10 through the channel, thereby replacing the gas in the second cavity 10. Therefore, it is not necessary to configure a through hole 20 for the second cavity 10. Those skilled in the art can choose to configure a through hole 20 for the second cavity 10 as an oil injection hole or an exhaust hole to facilitate later maintenance of the compressor. In order to simplify the processing of parts such as the cylinder block 1, it is also possible to configure a through hole 20 only for the first cavity 6.

[0126] Example 7:

[0127] This embodiment is a further refinement of embodiment 1:

[0128] It also includes a monitoring module, which is used to monitor the exhaust temperature of the reciprocating compressor and / or the vibration of the cylinder 1 during the gas compression process;

[0129] It also includes a control module, which is signal-connected to the monitoring module. The control module is configured to acquire the exhaust temperature and / or vibration signal, and determine whether the exhaust temperature exceeds a set temperature threshold and / or whether the vibration of cylinder 1 exceeds a set abnormal vibration threshold.

[0130] The control module is signal-connected to the control mechanism and the oil supply system. The control module is configured to: when the set temperature threshold and / or set vibration abnormality threshold determine that the exhaust temperature and / or vibration of the reciprocating compressor are abnormal, control the control mechanism and the oil supply system to operate. The oil supply system operates by: discharging oil from the third chamber 13 to reduce the internal pressure of the third chamber 13. The control mechanism operates by: keeping the channel in a state that connects the first chamber 6 and the second chamber 10, and after the intermediate piston 5 moves to increase the clearance of the reciprocating compressor, keeping the channel in a state that cuts off the connection between the first chamber 6 and the second chamber 10.

[0131] The above provides a monitoring module and a control module that, when abnormal compressor exhaust temperature or vibration is detected, uses a closed-loop control approach based on perception, judgment, and execution to increase clearance adjustment. In other words, this solution provides a technical approach that proactively addresses exhaust temperature and / or vibration abnormalities by actively adjusting the clearance. For those skilled in the art, the core concept of this solution lies in the implementation of the adjustment mechanism. For a compressor including this adjustment mechanism, when the monitoring parameters of the monitoring module and the fault judgment parameters of the control module include, for example, the current of the main piston 3 drive motor, and it is determined that this current has increased abnormally, in order to protect the compressor and ensure uninterrupted gas compression, the control module controls the control mechanism and the oil supply system to increase the compressor clearance and reduce the drive motor current. Such a closed-loop control approach to achieve proactive adjustment and protection should also be considered equivalent to the above concept. Furthermore, to meet the requirements for compressor efficiency, when the control module determines that the exhaust temperature and cylinder vibration have a safe margin based on the signal pickup results of the monitoring module, the compressor clearance can also be reduced through closed-loop control. To better protect the compressor, the compressor clearance can also be reduced by human intervention.

[0132] Example 8:

[0133] This embodiment is a further refinement of embodiment 1:

[0134] It also includes a first hydraulic oil that fills and fills the third cavity 13; and a second hydraulic oil that fills and fills the first cavity 6 and the second cavity 10, wherein the first hydraulic oil is hydraulic control oil and the second hydraulic oil is compressor lubricating oil, and the bulk elastic modulus of the hydraulic control oil is greater than that of the compressor lubricating oil.

[0135] As described above, the above solution provides a technical solution that enables the system to respond quickly and accurately when the oil supply system completes relevant adjustments, and avoids hydraulic oil contamination of the compressed gas and gas path, by distinguishing the hydraulic oil in different cavities. Preferably, the first hydraulic oil is servo hydraulic oil, and when the compressed gas of this reciprocating compressor is hydrogen or natural gas, the second hydraulic oil is compressor lubricating oil suitable for lubricating the main piston 3 of the reciprocating compressor.

[0136] Example 9:

[0137] Based on Embodiment 1, this embodiment provides a control method for a reciprocating compressor as described in any of the above embodiments. The control method includes the following steps:

[0138] Real-time monitoring of the exhaust temperature of the reciprocating compressor and / or the vibration of cylinder 1 during gas compression;

[0139] Based on real-time monitoring results, determine whether the reciprocating compressor exhibits a preset abnormal discharge temperature and / or abnormal vibration.

[0140] When it is determined that the exhaust temperature is abnormally high and / or the vibration is abnormal, the pressure of the hydraulic oil in the third chamber 13 is reduced by the oil supply system, and the first chamber 6 and the second chamber 10 are connected by the control mechanism and based on the channel.

[0141] Under the action of the gas pressure in the compression chamber 4 and / or the action of the reset device, the intermediate piston 5 moves along the axis of the piston chamber 2 and toward the side where the partition 9 is located, so as to increase the clearance of the piston compressor. The reset device is used to provide a continuous reset force to the intermediate piston 5, and the continuous reset force is directed toward the partition 9.

[0142] After the clearance increase adjustment is completed, the channel is cut off by the control mechanism to achieve isolation between the first cavity 6 and the second cavity 10.

[0143] It is easy to understand that the above control method is a control method for the above reciprocating compressor to deal with abnormal exhaust temperature and abnormal vibration. This control method is highly related to the hydrogen and natural gas compression process. As someone skilled in the art, the reciprocating compressor provided by this solution can also be adapted to clearance adjustment in other scenarios, such as only serving the adjustment of compressor discharge volume and compressor discharge pressure.

[0144] Example 10:

[0145] This embodiment is a further refinement of embodiment 9:

[0146] The method for determining whether a reciprocating compressor has abnormal vibration is as follows: perform anomaly analysis on the vibration signal and distinguish the fault type;

[0147] in:

[0148] If a first type of vibration abnormality characteristic corresponding to a liquid slugging fault in compression chamber 4 is identified, it is determined that a liquid slugging abnormality has occurred.

[0149] If a second type of abnormal vibration feature corresponding to leakage in the main piston 3 is identified, it is determined that a leakage abnormality has occurred.

[0150] One method to increase the clearance of a reciprocating compressor is as follows:

[0151] When a liquid slugging abnormality occurs, the position of the intermediate piston 5 is adjusted by the first preset displacement.

[0152] When only a leakage abnormality occurs, the position of the intermediate piston 5 is adjusted by the second preset displacement.

[0153] The first preset displacement is greater than the second preset displacement.

[0154] The above provides a specific technical solution based on vibration anomaly judgment, classification of anomaly causes, and matching of specific clearance adjustment amounts according to specific classifications. Specifically: when a liquid slugging anomaly is judged to occur, compared to a leakage anomaly, a method based on a larger intermediate piston 5 displacement adjustment is provided to improve the compressor's operational safety when liquid slugging occurs by using a larger clearance adjustment amount; when a leakage anomaly is judged to occur, compared to a liquid slugging anomaly, a method based on a smaller intermediate piston 5 displacement adjustment is provided to ensure the compressor's operating efficiency by using a smaller clearance adjustment amount.

[0155] In practice, the vibration anomaly can be judged based solely on the relatively simple vibration amplitude of cylinder 1. To improve the accuracy and reliability of fault type differentiation, the following scheme can be adopted to differentiate vibration anomalies:

[0156] In one specific embodiment, the vibration signal of the cylinder 1 is continuously acquired and the vibration signal is subjected to waveform analysis;

[0157] If an impact feature is detected in the waveform analysis results and the number of impact features exceeds a set number within a set operating cycle, it is determined that the piston compressor is experiencing abnormal vibration.

[0158] The impact features include a first impact feature corresponding to a liquid hammer anomaly and a second impact feature corresponding to a leakage anomaly.

[0159] The first impact characteristic is a vibration signal with a maximum amplitude greater than a first preset threshold and an amplitude rise rate greater than a second preset threshold;

[0160] The second impact characteristic is the leakage fault signal of the main piston 3 in the vibration signal spectrum, specifically: a vibration signal that occurs periodically in sync with the working frequency of the piston compressor, and whose maximum amplitude is greater than the third preset threshold and whose amplitude rise rate is greater than the fourth preset threshold.

[0161] The first preset threshold is greater than the third preset threshold, and the second preset threshold is greater than the fourth preset threshold.

[0162] In one specific embodiment, the vibration signal of the cylinder 1 is continuously acquired and the vibration signal is subjected to spectrum analysis;

[0163] If a feature corresponding to a specific fault is identified in the spectrum analysis results, and the feature continues or repeats within a set operating cycle, it is determined that the reciprocating compressor has a corresponding vibration abnormality.

[0164] The features include a first spectral feature corresponding to a liquid hammer anomaly and a second spectral feature corresponding to a leakage anomaly;

[0165] The first spectral feature is that a significant increase in energy occurs in a wide frequency band on the vibration signal spectrum: within multiple discrete frequency bands or continuous high-frequency bands, spectral components with amplitudes exceeding a first preset spectral threshold are detected.

[0166] The second spectral feature is that, on the vibration signal spectrum, at integer multiples (dominants) of the compressor's operating frequency, discrete spectral peaks with amplitudes exceeding a second preset spectral threshold appear, and the energy of these spectral peaks continues to occur over multiple consecutive operating cycles.

[0167] Wherein, the first preset spectrum threshold is greater than the second preset spectrum threshold.

[0168] Similar to the above-mentioned use of vibration signal waveforms, the fault type is distinguished by identifying spectral characteristics, and then the position adjustment of the intermediate piston 5 with different displacement is performed: after the clearance adjustment, the clearance under liquid hammer abnormality is greater than the clearance under leakage abnormality, so as to achieve the purpose of clearance adjustment that can simultaneously ensure the compressor compression efficiency and efficiently complete the elimination of abnormal vibration.

[0169] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An adjustable clearance reciprocating compressor, comprising a cylinder (1), wherein a piston chamber (2) is provided in the cylinder (1), a main piston (3) for pressurizing gas is provided in the piston chamber (2), and an intermediate piston (5) is provided in the piston chamber (2), wherein the intermediate piston (5) and the main piston (3) form a compression chamber (4): the intermediate piston (5) serves as the boundary of the compression chamber (4), and further comprising an adjustment mechanism for adjusting the position of the intermediate piston (5) in the axial direction of the piston chamber (2), characterized in that, The adjustment mechanism includes a partition (9) and a metal diaphragm (12). In the axial direction of the piston chamber (2), the main piston (3), the intermediate piston (5), the partition (9), the metal diaphragm (12), and the end plate (14) are arranged in sequence. The intermediate piston (5) and the partition plate (9) form a first cavity (6), the partition plate (9) and the metal diaphragm (12) form a second cavity (10), and the metal diaphragm (12) and the end plate (14) form a third cavity (13). The partition (9) is provided with a channel connecting the first cavity (6) and the second cavity (10), and the channel is equipped with a control mechanism to realize the channel opening and closing control; The third cavity (13) is equipped with an oil supply system for injecting and discharging hydraulic oil into the third cavity (13); The channel includes a first connecting hole (16) and a second connecting hole (17) that both penetrate the partition (9). The control mechanism includes a one-way valve assembly (11) and a solenoid valve assembly (8). The one-way valve assembly (11) is disposed on the first connecting hole (16). The one-way valve assembly (11) allows hydraulic oil to be injected from the second chamber (10) into the first chamber (6) and prevents hydraulic oil from being injected from the first chamber (6) into the second chamber (10). The second connecting hole (17) is equipped with a solenoid valve assembly (8), which is a normally closed valve. When the solenoid valve assembly (8) is in the closed state, the second connecting hole (17) is cut off. When the solenoid valve assembly (8) is in the open state, the second connecting hole (17) enables the first cavity (6) and the second cavity (10) to communicate.

2. The adjustable clearance piston compressor according to claim 1, characterized in that, It also includes a reset device that provides a continuous reset force to the intermediate piston (5) in the direction of the partition (9).

3. A reciprocating compressor with adjustable clearance according to claim 2, characterized in that, The reset device includes a tension spring (7) disposed in the first cavity (6), one end of which is fixed to the intermediate piston (5), and the other end of which is fixed to the partition (9).

4. A reciprocating compressor with adjustable clearance according to claim 1, characterized in that, It also includes a cylinder liner (15) embedded in the cylinder body (1), wherein the piston chamber (2) is formed on the cylinder liner (15): the piston chamber (2) is the center hole of the cylinder liner (15); The cylinder liner (15) is a two-section structure including an inner sleeve (18) and an outer sleeve (19). Relative to the end plate (14), the inner sleeve (18) is a cylinder liner (15) that extends into the cylinder body (1), and the outer sleeve (19) is a cylinder liner (15) whose inner end is connected to the outer end of the inner sleeve (18) and whose outer end is supported by the end plate (14). The main piston (3) and intermediate piston (5) are fitted in the inner sleeve (18), the partition (9) is formed on the outer sleeve (19), the control mechanism is fixed on the partition (9), and the edge of the metal diaphragm (12) is clamped between the outer sleeve (19) and the end plate (14).

5. A reciprocating compressor with adjustable clearance according to claim 1, characterized in that, It also includes a plurality of through holes (20) provided on the cylinder body (1), the through holes (20) serving as communication channels between the first cavity (6) and the outside of the cylinder body (1); Among the multiple through holes (20), there are through holes (20) whose inner opening is located on the bottom side of the first cavity (6) and through holes (20) whose inner opening is located on the top side of the first cavity (6). The number of through holes (20) whose opening is located on the top side of the first cavity (6) is greater than or equal to 2. The inner orifice is located in the through hole (20) on the bottom side of the first cavity (6), including an oil injection hole for injecting oil into the first cavity (6), and the inner orifice is located in the through hole (20) on the top side of the first cavity (6), including an exhaust hole for discharging gas from the first cavity (6) during the oil injection process. Both the oil injection hole and the exhaust hole are equipped with plugs. It also includes a sensor mounted on the cylinder (1) through a through hole (20) located on the top side of the first cavity (6), the sensor being configured to detect whether the top side region of the first cavity (6) contains gas.

6. A reciprocating compressor with adjustable clearance according to any one of claims 1 to 5, characterized in that, It also includes a monitoring module for monitoring the exhaust temperature of the reciprocating compressor and / or the vibration of the cylinder (1) during the gas compression process; It also includes a control module, which is signal-connected to the monitoring module. The control module is configured to acquire the exhaust temperature and / or vibration signal and determine whether the exhaust temperature exceeds a set temperature threshold and / or whether the vibration of the cylinder (1) exceeds a set abnormal vibration threshold. The control module is connected to the control mechanism and the oil supply system by signal. The control module is configured to: when the set temperature threshold and / or set vibration abnormality threshold determine that the exhaust temperature and / or vibration of the piston compressor is abnormal, control the control mechanism and the oil supply system to operate. The oil supply system operates by: draining oil from the third chamber (13) to reduce the internal pressure of the third chamber (13). The control mechanism operates by: keeping the channel in a state that connects the first chamber (6) and the second chamber (10), and after the intermediate piston (5) moves to increase the clearance of the piston compressor, keeping the channel in a state that cuts off the first chamber (6) and the second chamber (10).

7. A reciprocating compressor with adjustable clearance according to any one of claims 1 to 5, characterized in that, It also includes a first hydraulic oil that fills the third cavity (13) and is completely filled in the third cavity (13); it also includes a second hydraulic oil that fills the first cavity (6) and the second cavity (10) and is completely filled in the first cavity (6) and the second cavity (10), wherein the first hydraulic oil is hydraulic control oil and the second hydraulic oil is compressor lubricating oil, and the bulk elastic modulus of the hydraulic control oil is greater than that of the compressor lubricating oil.

8. A control method for a reciprocating compressor according to any one of claims 1 to 7, characterized in that, Includes the following steps: Real-time monitoring of the exhaust temperature of the reciprocating compressor and / or the vibration of the cylinder (1) during the gas compression process; Based on real-time monitoring results, determine whether the reciprocating compressor exhibits a preset abnormal discharge temperature and / or abnormal vibration. When it is determined that the exhaust temperature is too high and / or the vibration is abnormal, the pressure of the hydraulic oil in the third chamber (13) is reduced by the oil supply system, and the first chamber (6) and the second chamber (10) are connected by the control mechanism and based on the channel. The intermediate piston (5) moves along the axis of the piston chamber (2) and toward the side where the partition plate (9) is located under the action of the gas pressure in the compression chamber (4) and / or the action of the reset device, so as to increase the clearance of the piston compressor. After the clearance increase adjustment is completed, the channel is cut off by the control mechanism to achieve the isolation of the first cavity (6) and the second cavity (10).

9. The control method for a reciprocating compressor according to claim 8, characterized in that, The method for determining whether a reciprocating compressor has abnormal vibration is as follows: perform anomaly analysis on the vibration signal and distinguish the fault type; in: If a first type of vibration abnormality characteristic corresponding to a liquid slugging fault in the compression chamber (4) is identified, it is determined that a liquid slugging abnormality has occurred. If a second type of vibration abnormality characteristic corresponding to leakage in the main piston (3) is identified, it is determined that a leakage abnormality has occurred; One method to increase the clearance of a reciprocating compressor is as follows: When a liquid slugging abnormality occurs, the position of the intermediate piston (5) is adjusted by the first preset displacement. When only leakage abnormality occurs, the position of the intermediate piston (5) is adjusted by the second preset displacement; The first preset displacement is greater than the second preset displacement.

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