A plug valve grease injection system and cluster linkage control method thereof

Abstract

The present invention discloses a plug valve grease injection system and a cluster linkage control method thereof, including a plurality of grease injection units, which correspond to a plurality of plug valves one by one, and any grease injection unit includes: a grease injection cylinder, which includes a cylinder body; a cylinder head; a piston, which is an inverted T-shaped structure, the top end of which is sealed and slidably connected with the upper part of the inner cavity of the cylinder body to form a sealed grease cavity, and the bottom end is sealed and slidably connected with the lower part of the inner cavity of the cylinder body and separates it into two upper and lower hydraulic cavities; a displacement sensor, which is used to detect the displacement of the piston; a grease injection pipeline, which connects the sealed grease cavity and the plug valve; two hydraulic pipelines, which respectively connect the two hydraulic cavities and the hydraulic station; a heating and heat preservation device, which includes a temperature detection module and a heating and heat preservation module. The present invention combines the construction progress and the working state of each plug valve to perform cluster linkage control on the plurality of grease injection units, effectively improving the automation and intelligence of grease injection under complex working conditions, and ensuring the grease injection efficiency and grease injection effect.

Description

Technical Field

[0001] The present invention relates to the technical field of grease injection, and more specifically, to a plug valve grease injection system and a cluster linkage control method thereof. Background Art

[0002] In the prior art, manual grease injection is usually used to grease the valve body of the plug valve to ensure the opening and closing speed and sealing performance of the plug valve during operation. However, for application fields such as oil and gas testing, fracturing flowback, drilling and production, which have long construction periods, limited working space, a large number of plug valves, and frequent opening and closing operations, the above-mentioned manual grease injection method has defects such as cumbersome procedures, inconvenient operation, time-consuming and labor-consuming, and when the working environment temperature is too low, there is also a risk that the grease injection cannot be carried out smoothly and the grease injection effect is not good. In addition, during manual grease injection, the amount of grease added to the valve body each time and the amount of grease remaining in the filling equipment can only be judged by the subjective experience of the staff. The fault tolerance rate of this grease injection operation is low, and it is very easy to have problems such as under-injection, over-injection, insufficient grease in the filling equipment, and inability to refill in time, thereby affecting the grease injection efficiency and the working performance of the plug valve.

[0003] In order to solve the above problems, it is necessary to design a plug valve grease injection system and its cluster linkage control method to improve the adaptability of the plug valve grease injection operation to complex working conditions and ensure the grease injection efficiency and effect. Summary of the invention

[0004] The purpose of the present invention is to provide a plug valve grease injection system and a cluster linkage control method thereof. On the basis of ensuring a reliable grease injection environment, cluster linkage control is performed on multiple grease injection units in combination with the construction progress and the working status of each plug valve, while achieving precise control and judgment of the single grease injection amount and the remaining sealing grease, effectively improving the automation and intelligence of grease injection under complex working conditions, reducing manual errors, and ensuring grease injection efficiency and effects.

[0005] In order to achieve these purposes and other advantages according to the present invention, a plug valve grease injection system is provided, comprising a plurality of grease injection units corresponding to a plurality of plug valves one by one, and any grease injection unit comprises:

[0006] The grease injection cylinder comprises a cylinder body, inside of which is a stepped cavity with a narrow upper portion and a wide lower portion; a cylinder cover, which is arranged at the top opening of the stepped cavity and is sealed and connected thereto; a piston, which is an inverted T-shaped structure, with its top end sealingly and slidingly connected to the upper portion of the stepped cavity and forming a sealed grease cavity at the top, and its bottom end sealingly and slidingly connected to the lower portion of the stepped cavity and separating them to form two upper and lower hydraulic cavities; a displacement sensor, which is arranged to detect the displacement of the piston in the stepped cavity;

[0007] A grease injection pipeline connecting the sealing grease cavity and a valve body of a corresponding plug valve;

[0008] Two hydraulic pipelines, which correspond to the two hydraulic chambers respectively, and any hydraulic pipeline is connected to the corresponding hydraulic chamber and the hydraulic station;

[0009] A heating and heat preservation device, comprising a temperature detection module, which is configured to measure the real-time temperature of both sides of the grease injection pipeline; a heating and heat preservation module, which comprises an electric heating belt, which is wound around the cylinder body of the grease injection cylinder, the grease injection pipeline and the outer side wall of the valve body of the corresponding plug valve;

[0010] Wherein, the working states of the hydraulic station, each plug valve and its corresponding grease injection unit are all controlled by a control system.

[0011] Preferably, in the plug valve grease injection system, the heating and insulation module further comprises a thermal insulation layer, which is sleeved on the outside of the electric heating belt; and a protective layer, which is sleeved on the outside of the thermal insulation layer.

[0012] Preferably, in the plug valve grease injection system, the lower portion of the cylinder head extends into the step-shaped cavity and is threadedly connected thereto, and the lower portion of the cylinder head is further provided with a first sealing assembly configured to fill the gap between the cylinder head and the sealing grease cavity.

[0013] Preferably, in the plug valve grease injection system, the grease injection cylinder further comprises two second sealing assemblies, which are respectively arranged at both ends of the piston, and any second sealing assembly is a double sealing structure and is used to fill the gap between the end of the piston and the step-shaped cavity.

[0014] Preferably, in the plug valve grease injection system, the top of the hydraulic chamber located above in the grease injection cylinder is provided with a first oil filling port connected to the outer wall of the cylinder body, and the bottom of the hydraulic chamber located below is provided with a second oil filling port connected to the outer wall of the cylinder body, and the two hydraulic pipelines are connected to the two hydraulic chambers through the first oil filling port and the second oil filling port respectively.

[0015] Preferably, in the plug valve grease injection system, a mounting groove is provided on the bottom surface of the piston, which extends along the height direction of the piston to its upper part; the displacement sensor is a linear displacement sensor, the head end of its slide rail is fixedly arranged at the bottom of the cylinder body, the tail end of the slide rail is upwardly penetrated into the hydraulic cavity and the mounting groove in sequence, and the sliding part located on the slide rail is fixedly connected to the piston.

[0016] Preferably, in the plug valve grease injection system, the slide rail of the linear displacement sensor is sealingly connected to the step-shaped cavity, and a protective cover is provided on the outer side of the head end of the slide rail.

[0017] The present invention also provides a cluster linkage control method for a plug valve grease injection system, comprising:

[0018] S1. During the construction process, continuously monitor the working pressure of the manifold system where each plug valve is located, the construction progress of the working system, and the temperature status of each grease injection pipeline;

[0019] S2. When the working pressure of the manifold system is monitored to be 0, the temperature of each grease injection pipeline is checked according to the data fed back by the temperature detection module. When the real-time temperatures on both sides of the inner and outer sides of the grease injection pipeline are greater than 0°C, the temperature check is determined to have passed; when the temperature on the inner or outer side of the grease injection pipeline is less than or equal to 0°C, the temperature check is determined to have failed, and the corresponding heating and heat preservation module is started to perform heating and heat preservation until the temperature check of the grease injection pipeline passes;

[0020] S3, reading the construction progress of the working system where each plug valve is located, and judging the position of the plug valve to be greased in the working system and its grease injection demand according to its operation completion status;

[0021] S4, performing a grease injection inspection on the grease injection cylinder corresponding to the plug valve to be greased, determining the real-time position of the piston in the cylinder body according to the data fed back by the displacement sensor and calculating the amount of remaining sealing grease in the sealing grease cavity, and then determining whether the amount of remaining sealing grease in the grease injection cylinder meets the currently set grease injection requirement;

[0022] If it is satisfied, the grease injection inspection is judged to be qualified, and the grease injection cylinder is controlled to directly inject grease to the corresponding stopcock according to the grease injection demand; if it is not satisfied, the grease injection inspection is judged to be unqualified, and the grease injection cylinder needs to be filled with grease so that the sealing grease in the sealing grease cavity is filled to the maximum capacity, and then the grease injection cylinder is controlled to inject grease to the corresponding stopcock according to the grease injection demand.

[0023] Preferably, in the cluster linkage control method of the plug valve grease injection system, in S4, when controlling the grease injection cylinder to inject grease into the corresponding plug valve, firstly calculate the distance that the piston needs to move during the grease injection process according to the set grease injection demand, and then drive the piston to move to the set position in the direction close to the sealing grease chamber according to the set distance;

[0024] When the grease injection cylinder is filled with grease, the piston is first controlled to move to a limit position in a direction away from the sealing grease cavity, the cylinder cover is then opened to fill the sealing grease cavity with sealing grease from the outside, and finally the cylinder cover is closed.

[0025] Preferably, in the cluster linkage control method of the plug valve grease injection system, during grease injection, the corresponding plug valve is controlled to repeatedly open and close as the piston moves toward the sealing grease chamber until the piston moves to a set position.

[0026] The present invention has at least the following beneficial effects:

[0027] 1. The present invention drives the piston to move in the cylinder body by hydraulic pressure to squeeze the sealing grease cavity and inject grease into the plug valve through the grease injection pipeline. The displacement of the piston in the cylinder body is controlled by the control system, the displacement sensor and the hydraulic pipeline, so as to realize the real-time and accurate judgment and control of the single grease injection amount and the grease storage in the grease injection cylinder, effectively reduce the manual error, workload and sealing grease waste in the grease injection operation, and improve the grease injection efficiency and grease injection effect while reducing the cost;

[0028] 2. The present invention also provides a heating and heat preservation device in the grease injection unit, which effectively ensures the stability and reliability of the grease injection environment, overcomes the defect of poor seasonal adaptability in the existing manual grease injection method, is conducive to ensuring the grease injection efficiency and effect in harsh environments, and further ensures the smooth and efficient construction of the working system where the plug valve is located;

[0029] 3. Aiming at the situation that there are a large number of plug valves in the working system, the present invention configures a grease injection unit for each plug valve, which is centrally controlled by the control system, realizing an integrated intelligent automatic grease injection function, further improving the convenience, accuracy and work efficiency of the grease injection system operation;

[0030] 4. On the basis of ensuring a reliable grease injection environment, the present invention combines the construction progress and the working status of each stopcock to perform cluster linkage control on multiple grease injection units, ensuring precise control of the grease injection operation while enabling the operation process to be finely matched with the original construction process of the working system, effectively improving the automation and intelligence of the grease injection system and its adaptability to complex working conditions, thereby ensuring construction efficiency and quality.

[0031] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of a plug valve grease injection system according to one embodiment of the present invention;

[0033] Figure 2 It is a structural schematic diagram of the grease injection cylinder described in the above embodiment;

[0034] Figure 3 AA is a schematic diagram of the cross-sectional structure of the grease injection cylinder described in the above embodiment;

[0035] Figure 4 is a structural block diagram of the heating and heat preservation system described in the above embodiment;

[0036] Figure 5It is a flow chart of the cluster linkage control method of the plug valve grease injection system described in the above embodiment.

[0037] 1. Grease injection cylinder; 11. Cylinder body; 12. Cylinder head; 13. Handle; 14. Exhaust valve; 15. Piston; 16. Sealing grease chamber; 161. Grease injection port; 17. Hydraulic chamber; 171. First oil injection port; 172. Second oil injection port; 18. Displacement sensor; 19. Protective cover; 2. Plug valve; 3. Hydraulic pipeline; 4. Grease injection pipeline; 5. Heating and insulation system; 61. Control center; 62. Remote control computer; 63. Explosion-proof control box; 64. Solenoid valve box; 7. Hydraulic station; 81. Bottom plate; 82. Connecting plate; 83. Base; 84. Support plate. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0039] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] like Figure 1-5 As shown, the present invention provides a plug valve grease injection system, including a plurality of grease injection units, which correspond to a plurality of plug valves one by one, and any grease injection unit includes:

[0041] The grease injection cylinder 1 comprises a cylinder body 11, in which a stepped cavity with a narrow upper portion and a wide lower portion is provided; a cylinder cover 12, which is arranged at the top opening of the stepped cavity and is sealed and connected thereto; a piston 15, which is an inverted T-shaped structure, whose top end is sealed and slidably connected to the upper portion of the stepped cavity and forms a sealed grease cavity 16 on the upper portion, and whose bottom end is sealed and slidably connected to the lower portion of the stepped cavity and separates it into two upper and lower hydraulic cavities 17; a displacement sensor 18, which is arranged to detect the displacement of the piston 15 in the stepped cavity;

[0042] A grease injection pipeline 4, which connects the sealing grease cavity 16 with the valve body of the corresponding plug valve 2;

[0043] Two hydraulic pipelines 3, which correspond to the two hydraulic chambers 17 respectively, and any hydraulic pipeline connects the corresponding hydraulic chamber 17 with the hydraulic station 7;

[0044] A heating and heat preservation device, comprising a temperature detection module, which is configured to measure the real-time temperature of both sides of the grease injection pipeline; a heating and heat preservation module, which comprises an electric heating belt, which is wound around the cylinder body 11 of the grease injection cylinder 1, the grease injection pipeline 4 and the outer side wall of the valve body of the corresponding plug valve 2;

[0045] The working states of the hydraulic station 7, each plug valve 2 and its corresponding grease injection unit are all controlled by a control system.

[0046] In the above technical solution, when the cylinder head 12 is closed, the step-shaped cavity inside the cylinder body is a closed cavity, and under the separation effect of the piston 15, the above-mentioned closed cavity is divided from top to bottom into three independent (non-connected) cavities, namely, the sealing grease cavity 16 located between the top end of the piston and the cylinder head, the hydraulic cavity 17 located between the top end and the bottom end of the piston, and the hydraulic cavity 17 located between the bottom end of the piston and the bottom end of the cylinder body. Among them, the middle part of the cylinder head 12 is provided with a grease injection hole connected to the step-shaped cavity, and the top end of the grease injection hole protrudes outward to form a grease injection port 161, and the grease injection pipeline 4 is connected to the sealing grease cavity 16 through the grease injection port 161. The piston 15 located in the step-shaped cavity has a top structure (vertical top) that is adapted to the cross-sectional structure of the sealing grease cavity 16, and a bottom structure (horizontal part) that is adapted to the cross-sectional structure of the hydraulic cavity 17. When in use, the hydraulic station 7 can separately inject / discharge hydraulic oil into the corresponding hydraulic chamber 17 through the hydraulic pipeline 3. The on-off and flow rate of the two hydraulic pipelines 3 can control the pressure difference generated on the upper and lower sides of the bottom end (horizontal part) of the piston 15, thereby driving the bottom end of the piston to move in the lower part of the step-type cavity and driving the position of the top end of the piston in the sealing grease cavity to change. During the movement of the piston, the volumes of the three cavities will change dynamically under the structural limitations of the step-type cavity, and the sealing grease cavity 16 is filled with sealing grease. When the piston 15 moves upward, the sealing grease in the sealing grease cavity 16 will be squeezed, thereby driving the sealing grease to enter the grease injection pipeline 4 through the grease injection hole and be injected into the 2 valve bodies of the plug valve; similarly, when the sealing grease in the sealing grease cavity 16 is fully output or the remaining sealing grease cannot meet the next grease injection demand, the sealing grease cavity 16 can be refilled from the outside by hydraulically driving the piston 15 to move down and reset and opening the cylinder head 12. In the above sealing grease output / input process, the control of the single sealing grease output and the judgment of the remaining sealing grease amount can be achieved by analyzing the displacement data of the piston in the step-shaped cavity fed back by the displacement sensor. The displacement sensor 18 can be installed in any position in the grease injection cylinder 1 that can monitor the movement of the piston 15 and will not interfere with its normal movement, and the displacement sensor can be selected in various forms, such as a linear displacement sensor, a laser displacement sensor, etc. The control system can calculate the movement distance of the bottom end of the piston 15 relative to the bottom end of the step-shaped cavity (or the top end of the piston relative to the top end of the step-shaped cavity) by reading the real-time measurement data of the displacement sensor 18, and then combined with the design size of the grease injection cylinder 1, the amount of sealing grease injected into the plug valve 2 at a time (single displacement of the piston*inner diameter of the sealing grease cavity) and the amount of sealing grease remaining in the sealing grease cavity 16 (maximum capacity of the sealing grease cavity-the sum of all single grease injections after the most recent sealing grease filling) can be calculated.Therefore, the control system can accurately control the single grease injection amount according to the grease injection demand and the detection data fed back by the displacement sensor. Before each grease injection, it can also judge the feasibility of the current grease injection in advance according to the grease injection demand and the grease inventory in the grease injection cylinder, and perform the sealing grease filling / loading action accordingly, effectively reducing human errors, workload and sealing grease waste in the grease injection operation, and improving the grease injection efficiency and effect while reducing costs.

[0047] The grease injection unit is also integrated with a heating and heat preservation device, which is arranged in conjunction with the grease injection cylinder 1, the grease injection pipeline 4 and the corresponding plug valve 2 to provide temperature protection for the entire process of sealing grease input and output. When the temperature detection module detects that the internal temperature or ambient temperature (internal and external temperature) of the current grease injection pipeline does not meet the grease injection requirements, the electric heating tape in the heating and heat preservation module can be activated in time to heat the entire line area where the sealing grease is moved and stored (i.e. Figure 1 The area connected by the heating and insulation line (the heating and insulation line only indicates the coverage of the heating and insulation function, and the layout structure is not specifically shown) is heated and insulated, which effectively ensures the stability and reliability of the grease injection environment, overcomes the defect of poor seasonal adaptability in the existing manual grease injection method, and enables the sealing grease to be smoothly filled under suitable temperature conditions and play a sufficient sealing and lubricating role, thereby improving the grease injection efficiency and grease injection effect under harsh environments, thereby ensuring the original construction of the working system where the plug valve is located is smooth and efficient. In this embodiment, the temperature detection module can use two antifreeze temperature sensing probes, which are respectively installed on the inner wall and the outer wall of the grease injection pipeline 4. A heating and insulation system 5 is jointly constructed based on each heating and insulation device, such as Figure 1 , Figure 4 As shown, the heating and insulation system also includes a wireless transmission module, which is configured to send signals to a host computer (control system); a main thermostat, which is electrically connected to the temperature detection module, the heating and insulation module and the wireless transmission module to achieve two-way information transmission, that is, instructions from the control system can be sent to the main thermostat through the wireless transmission module, and then control the temperature detection module and the heating and insulation module to work, and at the same time, the working data of the temperature detection module and the heating and insulation module can also be fed back to the control system via the main thermostat and the wireless transmission module; a power module, which includes a battery, a distribution box and a solar charging module (sustainably powered by the battery), and the battery module is used to power the various components in the heating and insulation device (main thermostat, temperature detection module, heating and insulation module, etc.). Each heating and insulation device is centrally regulated and managed in the heating and insulation system. Specifically, the heating and insulation modules (electric heating tapes) located in the same manifold skid are connected in series to form a heating and insulation line. The heating and insulation lines of each manifold skid are connected in parallel to connect the heating and insulation devices as a whole. Each heating and insulation line is provided with a heating control switch. The main thermostat can adjust the working state of the heating and insulation modules on each heating and insulation line by controlling the on and off of each heating control switch, thereby realizing rapid maintenance of the grease injection environment.

[0048] The control system can perform cluster control on each grease injection unit, and identify and adjust the working status of the supporting hydraulic station 7, plug valve 2 and other components. Specifically, the control system has a built-in controller, and each hydraulic pipeline is provided with a solenoid valve; the displacement sensor 18 and the solenoid valve in the hydraulic station 7, each plug valve 2 and each grease injection unit are electrically connected to the controller (wired / wireless connection can be adopted), so that the controller can control the working status of the hydraulic station 7 and the hydraulic pipeline 3 (i.e., the oil injection situation in the two hydraulic chambers) according to the real-time data fed back by the displacement sensor 18, thereby controlling the displacement of the piston 15 in the stepped cavity, and realizing the precise control of the single grease injection amount; at the same time, the controller can also automatically record and store the historical displacement data of the piston starting from the zero position (initial position). Before each grease injection starts, the control system can calculate and judge whether the remaining sealing grease in the grease injection cylinder meets the next grease injection demand based on the above data, and control the various components in the system to perform corresponding actions (sealing grease is added outward / filled inward) according to the actual situation. In this embodiment, the plug valve 2 is a hydraulic plug valve. At this time, the hydraulic station 7 is connected to each plug valve 2 through another hydraulic pipeline to drive its operation (such as Figure 1 As shown in the figure, the above-mentioned hydraulic pipeline is also provided with a solenoid valve for controlling the working state of the pipeline (direction, flow rate, etc.). The solenoid valves on all hydraulic pipelines (the hydraulic pipeline connected to the plug valve 2, the hydraulic pipeline 3 connected to the grease injection cylinder 1) can be integrated in the same solenoid valve box 64, and the control signal lines between the plug valve 2, the grease injection cylinder 1 (displacement sensor) and the controller also pass through the solenoid valve box 64, which is convenient for unified management and maintenance. The control system includes a control center 61 (remote control terminal) and a remote control computer 62 (controller). The control center 61 and the remote control computer 62 can remotely transmit data by wired / wireless means. The remote instructions issued by the control center 61 can be immediately transmitted to each plug valve 2 and each solenoid valve in the solenoid valve box 64 after being received by the remote control computer 62; similarly, the working data generated by the plug valve 2, each hydraulic pipeline and each displacement sensor 18 are also fed back to the remote control computer 62 for data analysis and processing before being transmitted to the control center 61, which is convenient for the staff to confirm the working state and judge abnormal conditions. When the grease injection system is used in an inflammable and explosive environment (such as coal mines, oil mining, etc.), an explosion-proof control box 63 is further provided between the controller and the solenoid valve box, which is electrically connected to the controller and the solenoid valve box 64. The above control system realizes a high degree of integration of control functions while ensuring safety, and can quickly and conveniently control the working states of each stopcock, each grease injection cylinder and the heating and insulation device according to work requirements, so as to accurately and efficiently realize the automatic grease injection function, which is conducive to the management and centralized control of the overall working system.

[0049] In another technical solution, in the plug valve grease injection system, the heating and heat preservation module further includes a heat preservation layer, which is sleeved on the outside of the electric heating cable; and a protective layer, which is sleeved on the outside of the heat preservation layer. The heat preservation layer is made of common heat preservation materials and forms a sleeve-type structure tightly wrapped on the outside of the electric heating cable. The heat preservation materials may include expanded perlite, expanded vermiculite, diatomaceous earth or asbestos. The protective layer is fitted on the outside of the heat preservation layer to form an isolation protection for the heat preservation layer. The protective layer may include an asbestos cement shell protective layer made of a mixture of asbestos fiber and cement. In addition, a waterproof layer (such as oil felt, iron sheet or oiled glass cloth, etc.) may be added on the outside of the protective layer to prevent moisture from entering the heat preservation layer.

[0050] In another technical solution, in the plug valve grease injection system, the lower part of the cylinder head 12 extends into the step-shaped cavity and is threadedly connected thereto, and the lower part of the cylinder head 12 is also provided with a first sealing component, which is configured to fill the gap between the cylinder head 12 and the sealing grease cavity 16. Among them, the first sealing component can be a sealing ring or a sealing ring, which is embedded in the outer side of the lower part of the cylinder head (relatively fixed with the upper cylinder head) to fill the gap between the outer wall of the cylinder head and the inner wall of the cylinder body. Thus, while ensuring that the cylinder head can stably seal the top opening of the step-shaped cavity, the cylinder head and the cylinder body are quickly and detachably connected. When the cylinder head is closed (sealed), grease can only be injected into the plug valve through the grease injection hole in the middle of the cylinder head through the grease injection pipeline, which effectively avoids the problem of sealing grease leakage; when the control system determines that the sealing grease in the sealing grease cavity is insufficient, the cylinder head can be quickly opened to fill the sealing grease into the sealing grease cavity. For ease of use, a plurality of handles 13 may be provided at intervals along the circumferential direction on the upper outer side of the cylinder cover 12, and any handle 13 may extend radially outwardly along the cylinder cover 12, which is conducive to convenient and quick disassembly and assembly of the cylinder cover.

[0051] In addition, an exhaust valve 14 is provided on the outer side of the cylinder head, which is connected to the grease injection hole through the exhaust channel built into the cylinder head 12 (the grease injection hole is arranged along the axial direction of the cylinder body, and the exhaust channel connects the grease injection hole and the outside of the cylinder head 12 in a direction perpendicular to the grease injection hole), and the exhaust valve 14 is fixedly installed at the outer end of the exhaust channel. Therefore, when the piston 15 moves upward to squeeze the sealing grease cavity 16, the air in the sealing grease cavity can be discharged through the exhaust valve 14 first, and then the normal grease injection operation can be carried out; when the piston moves downward to reset, it can also avoid the problem that the sealing grease cavity 16 is pumped into a negative pressure, which makes it difficult to open the cylinder head 12.

[0052] In another technical solution, the plug valve grease injection system, the grease injection cylinder 1 also includes two second sealing components, which are respectively arranged at the two ends of the piston 15, and any second sealing component is a double sealing structure and is used to fill the gap between the end of the piston 15 and the step-shaped cavity. Wherein, the second sealing component can adopt conventional sealing parts (such as sealing rings, sealing rings, etc.) to make the corresponding components sealed and connected to avoid leakage of the medium in the sealed cavity (sealing grease cavity, hydraulic cavity) or mixing of the medium between adjacent cavities, which affects the normal operation of the grease injection cylinder. The double sealing structure can effectively ensure the sealing effect between the piston and the sealing grease cavity and the hydraulic cavity. Specifically, the second sealing component includes two sealing rings, which are arranged at the top or bottom of the piston at an axial interval along the piston, and any sealing ring is circumferentially sleeved on the outer wall of the piston and moves synchronously with it.

[0053] In another technical solution, in the plug valve grease injection system, the top of the hydraulic chamber 17 located at the top in the grease injection cylinder 1 is provided with a first oil injection port 171 communicating with the outer wall of the cylinder body 11, and the bottom of the hydraulic chamber 17 located at the bottom is provided with a second oil injection port 172 communicating with the outer wall of the cylinder body 11, and the two hydraulic pipelines 3 are respectively communicated with the two hydraulic chambers 17 through the first oil injection port 171 and the second oil injection port 172. In the above technical solution, both oil injection ports are L-shaped channel structures, the vertical part of which is communicated with the top surface / bottom surface of the corresponding hydraulic chamber 17, and the horizontal part extends outward to the outer wall of the cylinder body 11 and is communicated with the corresponding hydraulic pipeline 3, so that no matter what position the piston moves to, the hydraulic pipeline corresponding to the first oil injection port 171 can always be communicated with the upper hydraulic chamber, and the hydraulic pipeline corresponding to the second oil injection port 172 can always be communicated with the lower hydraulic chamber, thereby stably realizing the oil injection / oil return function under the control of the control system.

[0054] In another technical solution, in the plug valve grease injection system, the bottom surface of the piston 15 is provided with a mounting groove, which extends to the upper part of the piston along the height direction of the piston; the displacement sensor 18 is a linear displacement sensor, the head end of the slide rail is fixedly arranged at the bottom of the cylinder body, the tail end of the slide rail is inserted into the hydraulic chamber 17 and the mounting groove in sequence, and the sliding part located on the slide rail is fixedly connected with the piston 15. In the above technical solution, the piston 15 is set as a hollow structure, which provides an embedded installation space for the slide rail of the linear displacement sensor without affecting its movement. The piston and the sliding part of the linear displacement sensor move synchronously, and the real-time displacement of the piston can be measured by reading the electrical signal generated by the displacement of the sliding part on the slide rail. Specifically, the lower limit position of the piston moving in the hydraulic chamber is used as the zero position of the linear displacement sensor. When the piston moves upward (away from the zero position) driven by the pressure of the hydraulic oil, the output current of the displacement sensor becomes larger, and when it moves downward (close to the zero position), the output current of the displacement sensor becomes smaller. After receiving the real-time current data from the displacement sensor, the control system converts it into the position data of the piston, so as to accurately determine the real-time position of the piston in the step-type cavity, and then determine the current actual amount of grease injection; in addition, based on the grease injection data after the piston starts to move from the zero position (the sum of the displacements), the total amount of sealing grease output from the sealing grease cavity from the filled state to the current moment can be calculated, and then the remaining amount of sealing grease in the current sealing grease cavity can be calculated.

[0055] In this embodiment, the linear displacement sensor may be a magnetostrictive displacement sensor, which includes a measuring rod, an electronic compartment and a magnetic ring. The electronic compartment is fixed at the end of the measuring rod, and the magnetic ring slides non-contactly along the length direction of the measuring rod. Among them, a perforation is provided on the bottom surface of the cylinder body, and the measuring rod of the magnetostrictive displacement sensor penetrates from the outside to the inside into the hydraulic cavity located below, so that the electronic compartment is stuck at the bottom opening of the hydraulic cavity and closes it, which facilitates the electrical connection between the electronic compartment and the external controller. The magnetic ring is fixedly connected to the bottom end of the piston, so that when the piston moves, the real-time position of the piston can be determined by reading the moving position of the magnetic ring on the measuring rod.

[0056] In another technical solution, in the plug valve grease injection system, the slide rail of the linear displacement sensor is sealed and connected to the step-shaped cavity, and a protective cover 19 is provided on the outside of the head end of the slide rail. In the above technical solution, the head end of the slide rail of the linear displacement sensor closes the bottom opening of the hydraulic cavity 17 and extends out of the cylinder body 11. The electronic components of the sensor are usually integrated at this end. On the one hand, it is not easily affected by the medium (hydraulic oil) and pressure in the hydraulic cavity. On the other hand, it is convenient to connect with the external controller to transmit electrical signals. A protective cover 19 is additionally provided at the head end of the above slide rail, so that it is sleeved on the outside of each electronic component of the sensor, which can further play a protective role, avoid collisions and water ingress of electronic components, and ensure the normal, long-term and stable operation of the linear displacement sensor.

[0057] The present invention also provides a cluster linkage control method of the plug valve grease injection system, comprising:

[0058] S1. During the construction process, the working pressure of the manifold system where each plug valve 2 is located, the construction progress of the working system and the temperature status of each grease injection pipeline 4 are continuously monitored; wherein, the working pressure of the manifold system and the construction progress of the working system can be monitored by the original construction monitoring system (such as the pressure sensor and flow sensor installed on the manifold), and the temperature status of the grease injection pipeline 4 is monitored by its corresponding temperature detection module, and the above monitoring data are centrally fed back to the control system for unified processing and analysis.

[0059] S2. When the working pressure of the manifold system is monitored to be 0, the temperature of each grease injection pipeline 4 is checked according to the data fed back by the temperature detection module. When the real-time temperature of both the inside and outside of the grease injection pipeline 4 is greater than 0°C, it is determined that the temperature check has passed; when the temperature of the inside or outside of the grease injection pipeline 4 is less than or equal to 0°C, it is determined that the temperature check has failed, and the corresponding heating and heat preservation module is started to perform heating and heat preservation until the temperature check of the grease injection pipeline passes;

[0060] Among them, when the working pressure of the manifold system is monitored to be 0, it can be considered that the plug valve 2 is not working at this time, and grease injection or grease replenishment can be performed without interfering with its original working progress. On this basis, it is necessary to further determine whether the current grease injection environment meets the requirements. Specifically, the grease injection temperature is checked according to the real-time temperature data fed back by the temperature detection module. When the inner temperature or outer temperature of the grease injection pipeline corresponding to any heating and insulation device is less than or equal to 0°C, the heating system of the heating and insulation device needs to be started for heating until the ambient temperature and fluid temperature of the corresponding grease injection pipeline are both greater than 0°C, which means that the grease injection environment temperature is qualified and the subsequent grease injection / grease replenishment operation can be carried out normally.

[0061] S3, reading the construction progress of the working system where each plug valve is located, and judging the position of the plug valve to be greased in the working system and its grease injection demand according to its operation completion status;

[0062] Among them, since the position of the plug valve that needs to be greased in the system and its grease injection requirements may be quite different under different construction progresses and construction conditions, it is necessary to read the construction progress and construction status data of the overall working system before grease injection (the original construction monitoring system can also be used for data monitoring and transmission) in order to accurately, efficiently and automatically judge the current grease injection requirements (including the positioning of the plug valve and the setting of the amount of grease to be injected) according to the actual construction situation.

[0063] S4, performing a grease injection inspection on the grease injection cylinder 1 corresponding to the plug valve 2 to be greased, determining the real-time position of the piston 15 in the cylinder body 11 according to the data fed back by the displacement sensor 18, calculating the amount of remaining sealing grease in the sealing grease chamber 16, and then determining whether the amount of remaining sealing grease in the grease injection cylinder 1 meets the currently set grease injection requirement;

[0064] If it is satisfied, the grease injection inspection is judged to be qualified, and the grease injection cylinder 1 is controlled to directly inject grease to the corresponding plug valve 2 according to the grease injection demand; if it is not satisfied, the grease injection inspection is judged to be unqualified, and the grease injection cylinder 1 needs to be filled with grease, so that the sealing grease in the sealing grease cavity 16 is filled to the maximum capacity, and then the grease injection cylinder 1 is controlled to inject grease to the corresponding plug valve 2 according to the grease injection demand.

[0065] In the above technical solution, before grease injection, it is also necessary to perform a grease injection check according to the grease injection demand set in S3 and the corresponding sealing grease stock in the plug valve, that is, to determine whether the current sealing grease stock meets the grease injection / grease replenishment operation. When the sealing grease stock is sufficient, the piston in the grease injection cylinder can be directly controlled to move according to the displacement corresponding to the set grease injection amount and squeeze the sealing grease in the sealing grease cavity so that it can be smoothly injected into the valve body of the plug valve; if the sealing grease stock is insufficient, it is necessary to start the grease filling program first, control the piston in the grease injection cylinder to move and reset and open the cylinder cover, fill the sealing grease cavity with sealing grease by mechanical automatic or manual means, and then perform the original grease injection / grease replenishment operation after closing the cylinder cover. Among them, the filling amount of sealing grease can be calculated by the sealing grease stock obtained by previous judgment (the amount of grease to be filled = the maximum capacity of the sealing grease cavity - the sealing grease stock), and the control system transmits the calculated amount of grease to be filled to the external mechanical equipment or the operator, which is conducive to the efficient and accurate completion of the grease filling program.

[0066] In addition, in S4, for the case where there are multiple plug valves to be greased, the grease injection control process is: number the multiple plug valves to be greased, and execute the grease injection procedure (including grease injection inspection, grease injection / grease replenishment, grease filling, etc.) in the order of numbers, that is, when the grease injection procedure of a single plug valve is completed, start the corresponding grease injection procedure according to the specific grease injection requirements of the next plug valve to be greased until the grease injection or grease replenishment operation of all plug valves is completed.

[0067] The cluster linkage control method of the above-mentioned plug valve grease injection system combines multiple factors such as the working status of the plug valve, the status of the grease injection pipeline and the construction progress to perform cluster control on the grease injection operations of each plug valve in the working system. On the one hand, it greatly improves the intelligence and automation level of the grease injection operation, reduces the workload and operation cost of the grease injection operation, and ensures the quality and efficiency of the grease injection; on the other hand, this cluster control method enables the grease injection operation process to be finely matched with the original construction process of the working system, effectively improves the adaptability of the grease injection system to complex working conditions, avoids the interference of the plug valve maintenance operation (grease injection operation) on the original work of the plug valve, and maximizes the construction efficiency and construction quality of the overall working system.

[0068] In another technical solution, in the cluster linkage control method of the plug valve grease injection system, in S4, when controlling the grease injection cylinder to inject grease into the corresponding plug valve, firstly calculate the distance that the piston needs to move during the grease injection process according to the set grease injection demand, and then drive the piston to move to the set position in the direction close to the sealing grease cavity according to the set distance;

[0069] When the grease injection cylinder is filled with grease, the piston is first controlled to move to a limit position in a direction away from the sealing grease cavity, the cylinder cover is then opened to fill the sealing grease cavity with sealing grease from the outside, and finally the cylinder cover is closed.

[0070] In the above technical solution, the displacement direction of the piston can be controlled by adjusting the relative oil injection pressure in the two hydraulic chambers, and the specific displacement amount can be controlled according to the feedback data of the displacement sensor, that is, after the piston moves into place, the oil injection is stopped and the pressure in the two hydraulic chambers is ensured to be equal, so that the piston stops moving.

[0071] In another technical solution, the cluster linkage control method of the plug valve grease injection system controls the corresponding plug valve to repeatedly open and close during grease injection as the piston moves toward the sealing grease chamber until the piston moves to a set position, so that the sealing grease injected into the plug valve body can fully function, further improving the grease injection effect of the plug valve and ensuring the opening and closing speed and sealing performance of the plug valve in subsequent work.

[0072] Embodiment 1:

[0073] Taking a drilling fracturing construction project as an example, the overall fracturing operation platform consists of one or more single operating wells. The fracturing construction in a single operating well (according to the construction location and construction progress) is divided into several sections, any of which is called a single section operation. Each operating well is equipped with fracturing equipment, and each fracturing equipment performs fracturing operations under the control of the high and low pressure manifold system. The plug valve is set to control the on and off of the high pressure manifold in the manifold system.

[0074] A grease injection unit is configured and installed for each plug valve 2, which includes a grease injection cylinder 1, a grease injection pipeline 4, a hydraulic pipeline 3 and a heating and heat preservation device. The grease injection cylinder 1 includes a cylinder body 11, a cylinder head 12, a piston 15 and a displacement sensor 18. The cylinder body 11 is provided with a first oil injection port 171 and a second oil injection port 172. The cylinder head 12 is provided with a grease injection hole, a grease injection port 161, a handle 13 and an exhaust valve 14. The heating and heat preservation device includes a temperature detection module and a heating and heat preservation module. The temperature detection module includes two antifreeze temperature sensing probes. The heating and heat preservation module includes an electric heating belt, a heat preservation layer and a protective layer.

[0075] Specifically, the plug valve 2 is connected (communicated) with the grease injection port 161 on the cylinder head 12 of the corresponding grease injection cylinder 1 through the grease injection pipeline 4, and the first oil injection port 171 and the second oil injection port 172 on the cylinder body 11 of each grease injection cylinder are connected (communicated) with the hydraulic station 7 through the hydraulic pipeline 3, and antifreeze temperature probes are installed on the inner and outer sides of the grease injection pipeline 4, and electric heating tapes are installed on the plug valve body, grease injection pipeline and grease injection cylinder body, and the outer side is wrapped with insulation layers and protective layers layer by layer. The heating and heat preservation devices are connected to form multiple heating and heat preservation lines, and wireless transmission modules, main temperature controllers, power supply modules and other auxiliary devices are configured for them to form a heating and heat preservation system 5. After configuring the control system for each grease injection unit, hydraulic station and heating and heat preservation device, the construction of the overall plug valve grease injection system is completed. In addition, the displacement sensor 18 forms a bulge at the bottom of the cylinder body. In order to facilitate the on-site installation of the grease injection cylinder, a mounting bracket can be provided for it, which is supported at the bottom of the grease injection cylinder 1. The mounting bracket includes a bottom plate 81, which is fixedly connected to the bottom surface of the cylinder body 11 of the grease injection cylinder and has a mounting hole in the middle for the displacement sensor to pass through; a connecting plate 82, which is an inverted L-shaped structure, one end of its horizontal part is fixedly connected to the vertical part, and the other end is fixedly connected to one side of the bottom plate 81, and a support plate 84 is provided between the horizontal part and the vertical part of the connecting plate 82; a base 83, which is fixedly connected to the vertical part of the connecting plate 82. The positioning installation and stable support of the grease injection cylinder can be completed by installing the base of the mounting bracket at a suitable position in the construction area, and at the same time, it will not interfere with the structure of the displacement sensor.

[0076] The working principle of a single grease injection unit is as follows: in the initial state, the piston 15 is located at the bottom of the stepped cavity, at which time the sealing grease cavity 16 is at its maximum capacity and is filled with sealing grease. During the first grease injection, the single grease injection amount is set in advance according to the grease injection demand of the plug valve 2, and the required moving distance of the piston 15 in the sealing grease cavity 16 is calculated based on the grease injection amount; at the beginning of grease injection, the exhaust valve 14 is opened, and the hydraulic station 7 is controlled to inject hydraulic oil into the hydraulic cavity 17 from the second oil injection port 172, pushing the piston 15 upward, and the piston 15 squeezes the sealing grease in the sealing grease cavity 16 located above, so that it enters the valve body of the plug valve 2 through the grease injection hole and the grease injection pipeline 4. At this time, the hydraulic oil in the hydraulic cavity 17 located above can be discharged through the first oil injection port 171. When the displacement sensor 18 detects that the piston 15 has moved up a set distance, the second oil injection port 172 no longer takes in oil, and the exhaust valve 14 is closed, completing the single grease injection operation. When refilling, first confirm the current refilling demand (the amount of grease injected and the corresponding piston movement distance), and judge whether the remaining sealing grease in the grease injection cylinder 1 meets the refilling demand based on the historical detection data of the displacement sensor 18. After confirming that the amount of sealing grease in the sealing grease chamber meets the current refilling demand, inject hydraulic oil into the hydraulic chamber 17 from the second oil filling port 172 again to push the piston 15 to continue to move upward and refill the sealing grease into the plug valve 2. When the piston 15 moves the set distance, the second oil filling port 172 stops taking oil, and the refilling operation is completed. When it is determined before grease injection that the current amount of remaining sealing grease is insufficient for a single grease injection, the exhaust valve 14 is opened, and the hydraulic station 7 is controlled to inject hydraulic oil into the hydraulic chamber 17 from the first oil filling port 171, pushing the piston 15 downward to reset (to the initial position). At this time, the hydraulic oil in the hydraulic chamber 17 below can be discharged through the second oil filling port 172. After the piston is reset, the cylinder head 12 is opened to fill the sealing grease chamber 16 with sealing grease, and the cylinder head 12 is closed again to perform the original grease injection / refilling operation.

[0077] The specific process of the cluster linkage control method of the above-mentioned plug valve grease injection system is as follows:

[0078] S1. Use the fracturing construction monitoring system to continuously monitor the working pressure of the (high and low pressure) manifold system where each plug valve is located, the progress of fracturing construction and the temperature status of each grease injection pipeline, and select the remote / short-range control state in the plug valve grease injection system. The remote and short-range control states are locked with each other. After one operating state is determined, the other operating state is locked and cannot be operated.

[0079] S2. When the working pressure of the high-pressure manifold is monitored to be 0, it can be considered that each plug valve is in a non-working state, and the temperature of the grease injection environment is further checked. The inner temperature of the grease injection pipeline represents the pipeline fluid temperature, and the outer temperature of the grease injection pipeline represents the ambient temperature. When the ambient temperature obtained by the corresponding temperature detection module is ≤0℃ or the pipeline fluid temperature is ≤0℃, start the electric heating tape for heating. After the temperature of the grease injection cylinder + grease injection pipeline + plug valve is heated to above 0℃, keep it warm for a period of time before proceeding to the subsequent (grease injection) steps; when the ambient temperature is >0℃ and the pipeline fluid temperature is >0℃, the subsequent (grease injection) steps can be directly performed.

[0080] S3. Use the fracturing construction monitoring system to determine the current fracturing construction progress, and then determine the position of the plug valve to be greased and its grease injection requirements based on the current fracturing operation completion status. Specifically, first determine whether the fracturing system is in a platform or single well operation completion state. If it is not in a platform or single well operation completion state, further determine whether it is in a single-stage operation completion state. If it is still not in a single-stage operation completion state, return to the initial step (S1) to re-execute the control program; when it is determined that the fracturing system is in a platform / single well / single stage operation completion state, the plug valve with grease injection requirements in the fracturing system can be quickly located and its specific grease injection requirements (grease injection amount) can be determined. The grease injection requirements of the plug valve under different operation completion states can be preset in advance based on the fracturing construction parameters, plug valve design structure and construction experience.

[0081] In this embodiment, the method for judging the progress of the fracturing construction and the completion status of the operation is:

[0082] When the sand delivery and liquid volume monitored in this section reach the specified data and the working fluid pressure of the pipeline is zero, it can be considered that the single-section operation is completed; when the working fluid pressure of the pipeline connected to the well is zero and the motors of the pumps that transport high-pressure fluid to the well all stop working, it can be considered that the single-well operation is completed; when all single wells of the platform are in the operation completion state, it can be considered that the platform operation is completed.

[0083] S4. Execute the grease injection procedure for each plug valve to be greased, including: first, judging whether the current remaining amount of sealing grease meets the set grease injection demand based on the real-time position of the piston in the cylinder body; if the remaining amount of sealing grease is greater than or equal to the set single grease injection / grease replenishment amount, the plug valve is controlled to be repeatedly opened and closed while the piston is driven upward by hydraulic pressure until the piston moves the displacement amount corresponding to the set grease injection amount; if the remaining amount of sealing grease is less than the set single grease injection / grease replenishment amount, the cylinder cover is reset and opened by the hydraulic pressure driving the piston in the opposite direction, the sealing grease is loaded into the sealing grease cavity of the grease injection cylinder and then the cylinder cover is closed; when there is air in the sealing grease cavity (not completely filled), the piston can be driven to move upward by a suitable distance to discharge the air in the sealing grease cavity through the exhaust valve, and the position of the piston after the air is exhausted is used as the initial position of the piston in the subsequent grease injection / grease replenishment operation; then, the piston is driven according to the set grease injection demand and the plug valve is controlled to be repeatedly opened and closed; when the grease injection cylinder moves the displacement amount corresponding to the set grease injection amount, the repeated opening and closing of the plug valve is stopped, and the grease injection / grease replenishment operation is completed.

[0084] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A plug valve grease injection system, characterized in that: It includes multiple grease injection units, which correspond to multiple plug valves one by one. Any grease injection unit includes: The grease injection cylinder comprises a cylinder body, inside of which is a stepped cavity with a narrow upper portion and a wide lower portion; a cylinder cover, which is arranged at the top opening of the stepped cavity and is sealed and connected thereto; a piston, which is an inverted T-shaped structure, with its top end sealingly and slidingly connected to the upper portion of the stepped cavity and forming a sealed grease cavity at the top, and its bottom end sealingly and slidingly connected to the lower portion of the stepped cavity and separating them to form two upper and lower hydraulic cavities; a displacement sensor, which is arranged to detect the displacement of the piston in the stepped cavity; A grease injection pipeline connecting the sealing grease cavity and a valve body of a corresponding plug valve; Two hydraulic pipelines, which correspond to the two hydraulic chambers respectively, and any hydraulic pipeline is connected to the corresponding hydraulic chamber and the hydraulic station; A heating and heat preservation device, comprising a temperature detection module, which is configured to measure the real-time temperature of both sides of the grease injection pipeline; a heating and heat preservation module, which comprises an electric heating belt, which is wound around the cylinder body of the grease injection cylinder, the grease injection pipeline and the outer side wall of the valve body of the corresponding plug valve; Wherein, the working states of the hydraulic station, each plug valve and its corresponding grease injection unit are all controlled by a control system.

2. The plug valve grease injection system according to claim 1, characterized in that: The heating and heat-insulating module further comprises a heat-insulating layer, which is sleeved on the outside of the electric heating belt; and a protective layer, which is sleeved on the outside of the heat-insulating layer.

3. The plug valve grease injection system according to claim 1, characterized in that: The lower part of the cylinder cover extends into the step-shaped cavity and is threadedly connected thereto. The lower part of the cylinder cover is also provided with a first sealing assembly, which is configured to fill the gap between the cylinder cover and the sealing grease cavity.

4. The plug valve grease injection system according to claim 1, characterized in that: The grease injection cylinder also includes two second sealing components, which are respectively arranged at both ends of the piston. Any second sealing component has a double sealing structure and is used to fill the gap between the end of the piston and the step-shaped cavity.

5. The plug valve grease injection system according to claim 1, characterized in that: The top of the hydraulic chamber located at the top in the grease injection cylinder is provided with a first oil filling port connected to the outer wall of the cylinder body, and the bottom of the hydraulic chamber located at the bottom is provided with a second oil filling port connected to the outer wall of the cylinder body. The two hydraulic pipelines are connected to the two hydraulic chambers through the first oil filling port and the second oil filling port respectively.

6. The plug valve grease injection system according to claim 1, characterized in that: A mounting groove is provided on the bottom surface of the piston, which extends to the upper part of the piston along the height direction of the piston; the displacement sensor is a linear displacement sensor, the head end of its slide rail is fixedly arranged at the bottom of the cylinder body, and the tail end of the slide rail is upwardly penetrated into the hydraulic cavity and the mounting groove in sequence, and the sliding part located on the slide rail is fixedly connected to the piston.

7. The plug valve grease injection system according to claim 6, characterized in that: The slide rail of the linear displacement sensor is sealed and connected to the step-shaped cavity, and a protective cover is provided on the outer side of the head end of the slide rail.

8. The cluster linkage control method of the plug valve grease injection system according to claim 1, characterized in that: include: S1. During the construction process, continuously monitor the working pressure of the manifold system where each plug valve is located, the construction progress of the working system, and the temperature status of each grease injection pipeline; S2. When the working pressure of the manifold system is monitored to be 0, the temperature of each grease injection pipeline is checked according to the data fed back by the temperature detection module. When the real-time temperatures on both sides of the inner and outer sides of the grease injection pipeline are greater than 0°C, the temperature check is determined to have passed; when the temperature on the inner or outer side of the grease injection pipeline is less than or equal to 0°C, the temperature check is determined to have failed, and the corresponding heating and heat preservation module is started to perform heating and heat preservation until the temperature check of the grease injection pipeline passes; S3, reading the construction progress of the working system where each plug valve is located, and judging the position of the plug valve to be greased in the working system and its grease injection demand according to its operation completion status; S4, performing a grease injection inspection on the grease injection cylinder corresponding to the plug valve to be greased, determining the real-time position of the piston in the cylinder body according to the data fed back by the displacement sensor and calculating the amount of remaining sealing grease in the sealing grease cavity, and then determining whether the amount of remaining sealing grease in the grease injection cylinder meets the currently set grease injection requirement; If it is satisfied, the grease injection inspection is judged to be qualified, and the grease injection cylinder is controlled to directly inject grease to the corresponding stopcock according to the grease injection demand; if it is not satisfied, the grease injection inspection is judged to be unqualified, and the grease injection cylinder needs to be filled with grease so that the sealing grease in the sealing grease cavity is filled to the maximum capacity, and then the grease injection cylinder is controlled to inject grease to the corresponding stopcock according to the grease injection demand.

9. The cluster linkage control method of the plug valve grease injection system according to claim 8, characterized in that: In S4, when controlling the grease injection cylinder to inject grease into the corresponding plug valve, firstly calculate the distance that the piston needs to move during the grease injection process according to the set grease injection demand, and then drive the piston to move to the set position in the direction close to the sealing grease cavity according to the set distance; When the grease injection cylinder is filled with grease, the piston is first controlled to move to a limit position in a direction away from the sealing grease cavity, the cylinder cover is then opened to fill the sealing grease cavity with sealing grease from the outside, and finally the cylinder cover is closed.

10. The cluster linkage control method of the plug valve grease injection system according to claim 9, characterized in that: During grease injection, the corresponding stopcock is controlled to be repeatedly opened and closed during the process of the piston moving toward the sealing grease chamber until the piston moves to a set position.

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