High-pressure and high-temperature plunger pump packing seal closed flushing system and its working method

Abstract

The present invention relates to a high-pressure and high-temperature plunger pump stuffing box seal closed flushing system and its working method. The inlet of the pump seal flushing cavity of this system is connected to an external oil supply pipeline A with a first check valve, and the outlet is connected to an external liquid outlet pipeline B with a pressure switch valve. This system also includes a closed circulation loop, which includes an oil tank, an oil pump, a second check valve, a control valve, an oil return sight glass, a video probe, a throttle valve, a purification filter, and a cooler. The outlet of the oil pump in the closed circulation loop is connected to the inside of the oil tank through a loop with a first pressure control valve, and a first pressure transmitter is provided in the oil circuit at the inlet of the pump seal flushing cavity. A second pressure control valve and a second pressure transmitter are provided in the oil circuit between the outlet of the oil return sight glass and the purification filter. When the first temperature transmitter monitors that the oil return temperature exceeds the set value and / or the video probe discovers oil pollution through the oil return sight glass, the liquid outlet is switched from the closed circulation loop to the external liquid outlet pipeline B to maintain the reliable operation of the system.

Description

Technical Field

[0001] The present invention relates to the field of pumps, and is a high-pressure and high-temperature plunger pump stuffing box seal closed flushing system and its working method. Background Art

[0002] The high-pressure plunger feed pump is an important device in the fields of coal liquefaction and oil refining. Since the solid content, temperature, pressure, and viscosity of its conveying medium are all relatively high, and the working pressure is very high, a plunger pump is usually used to convey materials. To prevent a large amount of high-temperature, high-pressure, and high-viscosity medium from leaking when the seal fails, a triple stuffing box seal is generally used for the plunger pump. The currently adopted technical solution is to introduce a flushing oil from the outside into the middle section of the triple-seal stuffing box to flush the middle section of the stuffing box. The flushed oil is discharged from the outlet of the middle-section stuffing box, and the flushed oil is treated as waste oil separately or enters the downstream process unit for treatment. The function of the above flushing is to carry out the leaked material out of the stuffing box seal cavity to prevent the material from leaking; at the same time, the externally supplied clean flushing oil also carries out the particles worn off by the stuffing out of the stuffing box seal cavity to extend the life of the plunger and the stuffing. This flushing oil usually adopts wax oil, light diesel oil, and other high-temperature-resistant oils with good compatibility with the material. Currently, an open system is adopted, that is, it is supplied with oil from the external system and directly discharged outside after entering the stuffing box seal cavity. The required amount for each stuffing is about 0.2 - 1.5 m 3 / h. If there is no recycling and reuse, each pump wastes about 1600 - 12100 tons of flushing oil per year (calculated according to 8000 hours of annual operation hours). Even if re-refining and recycling are adopted, a large amount of energy will be consumed, which is not only not conducive to environmental protection, but also causes great waste and increases production costs. Therefore, it is necessary to improve the existing plunger pump flushing system. Summary of the Invention

[0003] To overcome the above deficiencies, the object of the present invention is to provide a high-pressure and high-temperature plunger pump stuffing box seal closed flushing system and its working method to the field. This system realizes closed-loop flushing, and solves the technical problems of large oil demand, serious waste, poor environmental protection, and high cost of oil recycling and utilization in the existing similar plunger pump stuffing box seal flushing systems. Its object is achieved through the following technical solutions.

[0004] A closed flushing system for the packing seal of a high-pressure and high-temperature piston pump. The system consists of an external oil supply pipeline A, a pump seal flushing chamber, and an external liquid outlet pipeline B. The inlet of the pump seal flushing chamber is connected to the external oil supply pipeline A with a first check valve, and the outlet of the pump seal flushing chamber is connected to the external liquid outlet pipeline B with a pressure switch valve. The key structural point is that the system also includes a closed circulation loop, which includes an oil tank, an oil pump, a second check valve, a control valve, an oil return sight glass, a video probe, a throttle valve, a purification filter, and a cooler. The oil tank is connected to the inlet of the oil pump, the outlet of the oil pump is connected to the inlet of the second check valve, the outlet of the second check valve is connected to the outlet of the first check valve and merges to be connected to the inlet of the pump seal flushing chamber. The outlet of the pump seal flushing chamber is provided with a first temperature transmitter for monitoring the temperature, and the outlet is divided into two paths. One path is connected to the external liquid outlet pipeline B through the pressure switch valve, and the other path is connected to the inlet of the oil return sight glass through the control valve. The video probe for identifying the pollution state of the oil in the oil return sight glass is provided at the oil return sight glass. The outlet of the oil return sight glass branches into two paths. One path is connected to the inlet of the throttle, and the other path is connected to the inlet of the purification filter. The outlet of the throttle is connected to the inlet of the cooler, and the outlets of the cooler and the purification filter are both connected into the oil tank. The outlet of the oil pump is connected into the oil tank through a loop with a first pressure control valve. A first pressure transmitter for detecting the oil pressure and correspondingly controlling the first pressure control valve is provided in the oil circuit at the inlet of the pump seal flushing chamber. A second pressure control valve is provided in the oil circuit between the outlet of the oil return sight glass and the purification filter, and a second pressure transmitter for monitoring the oil pressure and correspondingly controlling the second pressure control valve is provided in this oil circuit. In the initial state, the control valve is in the open state. The first pressure transmitter sets the pressure value of the oil circuit controlled by the first pressure control valve to be greater than the pressure value at the inlet of the first check valve, and the second pressure transmitter sets the pressure value of the oil circuit controlled by the second pressure control valve to be less than the pressure setting value of the pressure switch valve at the external liquid outlet pipeline B. Through the above structure, when the piston pump is operating normally, the oil supply circulation of the oil tank to the pump seal flushing chamber is realized through the closed circulation loop, thereby reducing the unnecessary consumption of flushing oil, greatly reducing the production cost of the liquid supply, and being beneficial to environmental protection. When the first temperature transmitter monitors that the oil return temperature exceeds the set value and / or the video probe finds oil pollution through the oil return sight glass, the control valve is closed and the pressure switch valve is opened.When there is packing leakage in the pump seal flushing cavity, the pumped medium leaks into the seal flushing cavity, and the return oil temperature will increase significantly. Therefore, the first temperature transmitter uses the monitored temperature state as the first monitoring for determining the leakage state; the video probe can directly observe the oil contamination state through the return oil sight glass, which can be used as the second monitoring for determining the occurrence of leakage; through these two monitors, the leakage state can be effectively identified and the control valve can be closed. Alarm information is sent through the first temperature transmitter and the video probe. At this time, the oil pump continues to work to supply oil to the pump seal flushing cavity, and the closed circulation loop automatically switches to the external circulation oil supply state where the oil pump supplies oil and boosts the pressure to be discharged to the external liquid outlet pipeline B, thus ensuring the continuous oil supply state of the pump seal flushing cavity and maintaining the reliable operation of the system.

[0005] The first pressure transmitter sets the pressure value controlled by the first pressure control valve in the oil circuit to be 0.1 - 0.3 MPa greater than the inlet pressure value of the first check valve, and the second pressure transmitter sets the pressure value controlled by the second pressure control valve in the oil circuit to be 0.05 - 0.2 MPa less than the pressure setting value of the pressure switch valve at the external liquid outlet pipeline B. With this structure, when the control valve is opened, the closed circulation loop supplies oil; when the control valve is closed, the oil pressure in the outlet pipeline of the pump seal flushing cavity increases to be greater than the pressure switch valve, so the pressure switch valve opens and drains oil to the external liquid outlet pipeline B.

[0006] A flow meter and a duplex filter are provided in the oil circuit between the outlet of the oil pump and the inlet of the second check valve. With this structure, the detection of the oil circuit flow and the reliable filtration of the oil are achieved.

[0007] A differential pressure monitor for monitoring the purification ability is provided in the purification filter. When the differential pressure monitored by the differential pressure monitor reaches the set value, the control valve closes. With this structure, when the differential pressure monitor identifies an increase in differential pressure, on the one hand, it indicates that the purifier is blocked and the purification components inside the purifier need to be replaced, and an alarm is provided to prompt that the purifier needs maintenance; on the other hand, as a detection of the oil contamination process, it can detect the working state of the purifier, thus serving as a reference basis for determining the oil contamination state.

[0008] The outlet of the cooler is branched into two paths and connected to the oil tank. One path is equipped with an on-line oil analyzer, and the other path is equipped with a temperature control valve. A second temperature transmitter for correspondingly controlling the temperature control valve is provided inside the oil tank. When the oil detected by the on-line oil analyzer is lower than the set value, the control valve closes. The setting of the second temperature transmitter and the temperature control valve is beneficial to controlling the amount of oil flowing out of the cooler, thereby adjusting the temperature of the oil returning to the oil tank and ensuring the temperature required for the oil supply in the oil tank. That is, when the oil temperature in the oil tank is higher than the set value, the opening degree of the temperature control valve is increased to increase the amount of cooled oil entering the oil tank and reduce the oil temperature in the oil tank; when the oil temperature in the oil tank is lower than the set value, the opening degree of the temperature control valve is reduced to reduce the amount of cooled oil entering the oil tank and maintain the oil temperature in the oil tank. The on-line oil analyzer is used to monitor parameters such as particles, moisture, viscosity, and chromaticity in the oil return pipeline. When the oil detected by the on-line oil analyzer is lower than the set value, this is used as a further determination of the leakage condition of the packing in the pump seal flushing chamber, that is, the on-line oil analyzer realizes the third-stage monitoring.

[0009] At least two regions are formed inside the oil tank by partitioning with a partition board. The oil between the regions communicates through overflow. A diversion baffle for guiding and defoaming the incoming oil is provided inside the oil tank, and it is diverted to the region separated by the first partition board inside the oil tank. Through this structure, the incoming oil can be subjected to multi-stage sedimentation treatment. And when the leakage of the pump seal flushing chamber is serious, the pollution state of the oil returning to the oil tank will not immediately affect the oil state of the oil supply, thereby gaining more buffer time and facilitating problem handling.

[0010] An oil mist purification and recovery device for purifying and recovering the oil mist formed in the oil tank is provided at the top of the oil tank. The recovery of the oil mist is realized through the oil mist purification and recovery device. A heater for heating the oil in the oil tank is provided inside the oil tank, and the temperature in the oil tank is adjusted by heating through the heater; the amount of oil entering the oil tank after cooling is controlled by the temperature control valve to realize the cooling adjustment of the oil temperature in the oil tank, and the oil temperature in the oil tank can be accurately controlled.

[0011] The control valve is an electric valve, and a status alarm is associated with it. That is, when the control valve closes, the alarm sounds. Through this structure, the purpose of status reminder is achieved, which is convenient for maintenance personnel to handle problems in time.

[0012] A make-up oil circuit is provided between the oil tank and the inlet of the first check valve. A make-up liquid valve is provided in the make-up oil circuit. A liquid level transmitter for sensing the oil level and controlling the opening of the make-up liquid valve is provided inside the oil tank. Through this structure, automatic make-up oil is realized when the oil in the oil tank is insufficient, so that even if the first check valve fails, normal operation can still be achieved, ensuring reliable operation of the equipment.

[0013] The working method of the packing seal closed flushing system for the high-pressure and high-temperature plunger pump is as follows: In the initial state, the control valve is in the open state. When there is no packing leakage pollution in the pump seal flushing cavity, the oil pump pumps the oil in the oil tank into the pump seal flushing cavity along the second check valve according to the pressure set by the first pressure transmitter. Since the oil pressure in the oil circuit where the second check valve is located is greater than the liquid inlet pressure of the external oil supply pipeline A, the first check valve automatically closes. After passing through the pump seal flushing cavity, the oil first passes through the first temperature transmitter to monitor the oil temperature, and then enters the oil return sight glass oil circuit. The video probe at the oil return sight glass monitors the pollution state of the oil. After passing through the throttle valve, part of the oil is cooled by the cooler and then returned to the oil tank, and the other part is filtered by the purification filter and then returned to the oil tank. The above realizes a closed circulation loop. When the temperature monitored by the first temperature transmitter exceeds the set value and / or the video probe monitors that the pollution state of the oil reaches the set value, it is recognized that the pump medium leaks into the pump seal flushing cavity. The control valve closes to cut off the oil return, and the oil pump continues to work. The pressure in the pump seal flushing cavity rises until the pressure switch valve opens, and the system automatically discharges the polluted flushing oil to the external liquid outlet pipeline B. Since the control valve closes and there is no oil return to the oil tank, the oil pump continues to work. When the first pressure transmitter recognizes that the oil pressure value is insufficient, and the outlet oil pressure of the second check valve is less than the inlet oil pressure of the first check valve, the first check valve automatically opens and the second check valve automatically closes. The pump seal flushing cavity is directly supplied with liquid for flushing by the external oil supply pipeline A and discharged to the outside through the external liquid outlet pipeline B, so as to realize the switching of the pump seal flushing cavity to the external oil supply open flushing mode and maintain the normal operation of the plunger pump. After the problem of plunger pump medium leakage is solved, the closed circulation loop liquid supply is restarted.

[0014] On the basis of the existing external flushing system for the plunger pump seal, the present invention adds an internal closed circulation loop, thus eliminating the need for continuous external liquid supply, greatly reducing the consumption of flushing oil, significantly reducing the operating cost of the plunger pump, being more environmentally friendly, and having the function of monitoring the leakage of the pump seal flushing cavity, effectively monitoring the leakage state. Even if the closed-loop flushing system fails, it can automatically switch to the external open flushing state, still ensuring that the plunger pump seal packing is effectively flushed, improving the stable and reliable operation of the equipment, and being a system with intrinsically safe design; it is suitable for use as the flushing system for the pump seal flushing cavity of various plunger pumps or the structural improvement of similar systems. Brief Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the principle structure of the present invention. In the figure, A represents the external oil supply pipeline A, and B represents the external liquid outlet pipeline B.

[0016] The serial numbers and names in the figure are as follows: 1. fuel tank, 2. partition board, 3. diversion baffle, 4. heater, 5. oil level transmitter, 6. oil pump, 7. first pressure control valve, 8. duplex filter, 9. flowmeter, 10. make-up valve, 11. first check valve, 12. second check valve, 13. first pressure transmitter, 14. pump seal flushing chamber, 15. oil mist purification and recovery unit, 16. first temperature transmitter, 17. pressure switch valve, 18. control valve, 19. return oil sight glass, 20. video probe, 21. second pressure transmitter, 22. second pressure control valve, 23. restrictor, 24. purification filter, 25. cooler, 26. on-line oil quality analyzer, 27. temperature control valve, 28. second temperature transmitter. Detailed implementation manners

[0017] The invention will be further described below in conjunction with the accompanying drawings.

[0018] As Figure 1As shown in the figure, the packing seal closed flushing system of the high-pressure and high-temperature plunger pump includes an external oil supply pipeline A, a pump seal flushing chamber 14, and an external liquid outlet pipeline B. The inlet of the pump seal flushing chamber is connected to the external oil supply pipeline A with a first check valve 11, and the outlet of the pump seal flushing chamber is connected to the external liquid outlet pipeline B with a pressure switch valve 17. The system also includes a closed circulation loop, which includes an oil tank 1, an oil pump 6, a second check valve 12, a control valve 18, an oil return sight glass 19, a video probe 20, a throttle valve 23, a purification filter 24, and a cooler 25. The outlet of the oil tank is connected to the inlet of the oil pump, the outlet of the oil pump is connected to the inlet of the second check valve, the outlet of the second check valve is connected to the outlet of the first check valve and merges to connect to the inlet of the pump seal flushing chamber. The outlet of the pump seal flushing chamber is provided with a first temperature transmitter 16 for monitoring the temperature, and the outlet branches into two paths. One path is connected to the external liquid outlet pipeline B through the pressure switch valve, and the other path is connected to the inlet of the oil return sight glass through the control valve. A video probe for identifying the pollution state of the oil in the oil return sight glass is provided at the oil return sight glass. The outlet of the oil return sight glass branches into two paths. One path is connected to the inlet of the throttle valve, and the other path is connected to the inlet of the purification filter. The outlet of the throttle valve is connected to the inlet of the cooler, and the outlets of the cooler and the purification filter are both connected to the inside of the oil tank. The outlet of the oil pump is connected to the inside of the oil tank through a loop with a first pressure control valve 7. A first pressure transmitter 13 for monitoring the oil pressure and correspondingly controlling the first pressure control valve is provided in the oil circuit at the inlet of the pump seal flushing chamber. A second pressure control valve 22 is provided in the oil circuit between the outlet of the oil return sight glass and the purification filter, and a second pressure transmitter 21 for monitoring the oil pressure and correspondingly controlling the second pressure control valve is provided in this oil circuit. In the initial state, the control valve is in the open state. The first pressure transmitter sets the pressure value of the oil circuit controlled by the first pressure control valve to be 0.1 - 0.3 MPa greater than the inlet pressure value of the first check valve, and the second pressure transmitter sets the pressure value of the oil circuit controlled by the second pressure control valve to be 0.05 - 0.2 MPa less than the pressure setting value of the pressure switch valve at the external liquid outlet pipeline B. When the first temperature transmitter and / or the video probe monitors that the oil temperature and the oil pollution degree reach the set values, the control valve closes. The video probe provides video signal images for remote observation and judgment by personnel, and image analysis software or light transmittance monitoring can also be used for alarm.

[0019] Furthermore, a flow meter 9 and a duplex filter 8 are provided in the oil circuit between the outlet of the oil pump 6 and the inlet of the second check valve 12. A pressure differential monitor is provided in the purification filter 24 to monitor the purification operating status. When the pressure differential monitor identifies insufficient purification capacity, an alarm signal is provided. The outlet of the cooler 25 branches into two routes connected to the oil tank, one of which is equipped with an online oil analyzer 26, and the other is equipped with a temperature control valve 27. A second temperature transmitter 28 is provided in the oil tank to control the corresponding temperature control valve. When the oil temperature detected by the second temperature transmitter is higher than the set value, the temperature control valve opens wider, and vice versa. The oil tank is divided into multiple zones by partitions 2, and the oil between the zones is overflow-connected. A diversion baffle 3 is provided in the oil tank to guide and defoam the incoming oil, and the oil is diverted to the area separated by the first partition in the oil tank. A heater 4 is provided in the oil tank to heat the oil in the tank. An oil mist purifier and recycler 15 is installed on the top of the oil tank to purify and recycle the oil mist formed in the oil tank. An oil replenishment circuit is provided between the oil tank and the inlet of the first check valve. A liquid replenishment valve 10 is installed in the oil replenishment circuit. A liquid level transmitter 5 is installed in the oil tank to sense the oil level and control the opening of the liquid replenishment valve.

[0020] In order to further ensure the safe and reliable operation of the equipment, the control valve 18 is an electric valve and is associated with an alarm. That is, when the control valve is closed, the alarm sounds an alarm to remind maintenance personnel to deal with it in time.

[0021] The control valve 18 is connected to the first temperature transmitter 16, video probe 29, second temperature transmitter 28, and online oil analyzer 26, all of which are monitored via a control circuit. This control circuit can be configured as needed. The first temperature transmitter, video probe, and second temperature transmitter can also be connected to an alarm device to achieve better monitoring. Furthermore, the oil pump can be configured in two groups: one for active operation and the other for standby operation. If one group fails, the other can provide immediate backup.

[0022] The working method of the system is as follows: In the initial state, the control valve 18 is open. When there is no packing leakage pollution in the pump seal flushing cavity 14, the oil pump 6 pumps the oil in the oil tank 1 into the pump seal flushing cavity along the second check valve 12 at the pressure set by the first pressure transmitter 13. Since the oil pressure in the oil path where the second check valve is located is greater than the liquid inlet pressure of the external oil supply pipeline A, the first check valve 11 automatically closes. After passing through the pump seal flushing cavity, the oil first passes through the first temperature transmitter 16 to monitor the oil temperature, and then enters the oil path where the oil return sight glass 19 is located. The video probe 20 at the oil return sight glass monitors the pollution state of the oil. After passing through the throttle valve 23, part of the oil is cooled by the cooler 25 and then returned to the oil tank, and the other part is filtered by the purification filter 24 and then returned to the oil tank, thus realizing a closed circulation loop. When the temperature monitored by the first temperature transmitter exceeds the set value and / or the video probe monitors that the pollution state of the oil reaches the set value, it is identified that the pump medium leaks into the pump seal flushing cavity. The control valve closes, the oil return is cut off, the oil pump continues to work, and the pressure in the pump seal flushing cavity rises until the pressure switch valve 17 opens, and the system automatically discharges the polluted flushing oil to the external liquid outlet pipeline B. Since the control valve closes and there is no oil return to the oil tank, the oil pump continues to work, and the decrease in the oil tank liquid level triggers the liquid filling valve to replenish the oil tank. At this time, the working state of the system is: the external oil supply is in an external discharge open oil supply state after being pressurized by the oil pump. The two oil pumps set in the figure are in an open and closed state. When the first pressure transmitter identifies that the oil pressure value is insufficient, the second oil pump is started to work, and at the same time, the oil pressure is alarmed. When both oil pumps fail to work or the oil pumps are closed, the oil pressure at the outlet of the second check valve is less than the oil pressure at the inlet of the first check valve. The first check valve automatically opens, and the second check valve automatically closes. The external oil supply pipeline A directly supplies liquid to flush the pump seal flushing cavity, and discharges it to the outside through the external liquid outlet pipeline B, thereby realizing the switch of the pump packing seal cavity to the external oil supply open flushing mode to maintain the normal operation of the plunger pump. After the problem of plunger pump medium leakage is solved, the closed system is restarted to realize the liquid supply of the closed circulation loop.

[0023] The above content is intended to illustrate the technical means of the present invention and does not limit the technical scope of the present invention. Obvious improvements or replacements made by those skilled in the art to the present invention in combination with the existing common general knowledge also fall within the protection scope of the claims of the present invention.

Claims

1. A high-pressure and high-temperature plunger pump stuffing box seal closed flushing system, which system comprises an external oil supply pipeline A, a pump seal flushing cavity (14), and an external liquid discharge pipeline B. The inlet of the pump seal flushing cavity is connected to the external oil supply pipeline A with a first check valve (11), and the outlet of the pump seal flushing cavity is connected to the external liquid discharge pipeline B with a pressure switch valve (17); characterized in that The system further includes a closed-loop circuit, which includes an oil tank (1), an oil pump (6), a second check valve (12), a control valve (18), an oil return sight glass (19), a video probe (20), a throttle valve (23), a purification filter (24), and a cooler (25). The oil tank is connected to the inlet of the oil pump. The outlet of the oil pump is connected to the inlet of the second check valve. The outlet of the second check valve is connected to the outlet of the first check valve and joined to the inlet of the pump seal flushing chamber (14). The outlet of the pump seal flushing chamber is provided with a first temperature transmitter (16) for monitoring temperature, and the outlet is divided into two paths. One path is connected to the external liquid outlet pipeline B through the pressure switch valve (17), and the other path is connected to the inlet of the oil return sight glass through the control valve. The video probe for identifying the pollution state of the oil in the oil return sight glass is provided at the oil return sight glass. The outlet of the oil return sight glass branches into two paths. One path is connected to the inlet of the throttle valve, and the other path is connected to the inlet of the purification filter. The outlet of the throttle valve is connected to the inlet of the cooler. The outlets of the cooler and the purification filter are both connected into the oil tank. The outlet of the oil pump is connected into the oil tank through a circuit with a first pressure control valve (7). A first pressure transmitter (13) for monitoring oil pressure and correspondingly controlling the first pressure control valve is provided in the oil circuit at the inlet of the pump seal flushing chamber. A second pressure control valve (22) is provided in the oil circuit between the outlet of the oil return sight glass and the purification filter, and a second pressure transmitter (21) for correspondingly monitoring oil pressure and controlling the second pressure control valve is provided in this oil circuit. In the initial state, the control valve (18) is in an open state. The first pressure transmitter sets the pressure value of the oil circuit controlled by the first pressure control valve to be greater than the pressure value at the inlet of the first check valve. The second pressure transmitter sets the pressure value of the oil circuit controlled by the second pressure control valve to be less than the pressure setting value of the pressure switch valve at the external liquid outlet pipeline B. When the first temperature transmitter monitors that the oil return temperature exceeds the set value and / or the video probe discovers oil pollution through the oil return sight glass, the control valve closes and the pressure switch valve opens.

2. The high-pressure and high-temperature plunger pump packing seal closed flushing system according to claim 1, characterized in that The first pressure transmitter (13) sets the pressure value of the oil circuit controlled by the first pressure control valve (7) to be 0.1 - 0.3 MPa greater than the pressure value at the inlet of the first check valve (11). The second pressure transmitter (21) sets the pressure value of the oil circuit controlled by the second pressure control valve (22) to be 0.05 - 0.2 MPa less than the pressure setting value of the pressure switch valve (17).

3. The closed flushing system for the packing seal of the high-pressure and high-temperature plunger pump according to claim 1, wherein A flowmeter (9) and a duplex filter (8) are provided in the oil circuit between the outlet of the oil pump (6) and the inlet of the second check valve (12).

4. The high-pressure and high-temperature plunger pump packing seal closed flushing system according to claim 1, characterized in that A differential pressure monitor for monitoring the purification ability is provided in the purification filter (24). When the differential pressure monitored by the differential pressure monitor reaches the set value, the control valve (18) closes.

5. The high-pressure and high-temperature plunger pump packing seal closed flushing system according to claim 1, characterized in that The outlet of the cooler (25) is connected to the oil tank (1) in two branches. One branch is equipped with an on-line oil analyzer (26), and the other branch is equipped with a temperature control valve (27). A second temperature transmitter (28) for correspondingly controlling the temperature control valve is provided in the oil tank. When the oil detected by the on-line oil analyzer is lower than the set value, the control valve (18) closes.

6. The high-pressure and high-temperature plunger pump packing seal closed flushing system according to claim 1, characterized in that At least two regions are formed in the oil tank (1) by separating with a partition plate (2). The oil fluid between the regions communicates with each other by overflow. A flow guiding baffle (3) for guiding and defoaming the incoming oil fluid is provided in the oil tank, and the oil fluid is guided into the region separated by the first partition plate in the oil tank.

7. The high-pressure and high-temperature plunger pump packing seal closed flushing system according to claim 1, characterized in that An oil mist purification and recovery device (15) for purifying and recovering the oil mist formed in the oil tank is provided at the top of the oil tank (1); a heater (4) for heating the oil fluid in the oil tank is provided in the oil tank.

8. The high-pressure and high-temperature plunger pump stuffing box seal closed flushing system according to claim 1, characterized in that The control valve (18) is an electric valve, and an alarm is associated therewith. That is, when the control valve closes, the alarm gives an alarm.

9. The high-pressure and high-temperature plunger pump stuffing box seal closed flushing system according to claim 1, characterized in that A supplementary oil circuit is provided between the oil tank (1) and the inlet of the first check valve (11). A liquid supplement valve (10) is provided in the supplementary oil circuit. A liquid level transmitter (5) for sensing the height of the oil fluid and controlling the opening of the liquid supplement valve is provided in the oil tank.

10. A working method of the high-pressure and high-temperature plunger pump stuffing box seal closed flushing system as described in claim 1, characterized in that The working method of this system is as follows: In the initial state, the control valve (18) is in the open state. When there is no packing leakage pollution in the pump seal flushing cavity (14), the oil pump (6) pumps the oil fluid in the oil tank (1) into the pump seal flushing cavity along the second check valve (12) according to the pressure set by the first pressure transmitter (13). Because the oil pressure in the oil circuit where the second check valve is located is greater than the inlet liquid pressure of the external oil supply pipeline A, the first check valve automatically closes. After passing through the pump seal flushing cavity, the oil fluid first passes through the first temperature transmitter (16) to monitor the oil fluid temperature, and then enters the oil circuit where the return oil sight glass (19) is located. The video probe (20) at the return oil sight glass monitors the pollution state of the oil fluid. After the oil fluid passes through the throttle valve (23), a part of it is cooled by the cooler (25) and then returned to the oil tank, and the other part is filtered by the purification filter (24) and then returned to the oil tank. The above realizes a closed circulation loop; when the temperature monitored by the first temperature transmitter exceeds the set value and / or the video probe monitors that the pollution state of the oil fluid reaches the set value, it is identified that the pump medium leaks into the pump seal flushing cavity, the control valve closes to cut off the return oil, the oil pump continues to supply pressure, and the pressure in the pump seal flushing cavity rises until the pressure switch valve (17) opens, and the system automatically discharges the polluted flushing oil to the external liquid outlet pipeline B; because the control valve closes to cut off the return oil of the oil tank and the oil pump continues to work, when the first pressure transmitter identifies that the oil fluid pressure value is insufficient, that is, the outlet oil fluid pressure of the second check valve is less than the inlet oil fluid pressure of the first check valve, the first check valve automatically opens, the second check valve automatically closes, and the external oil supply pipeline A directly supplies liquid to flush the pump seal flushing cavity and discharges it to the outside through the external liquid outlet pipeline B, so as to realize the switching of the pump seal flushing cavity to the external oil supply open flushing mode and maintain the normal operation of the plunger pump; after solving the pump medium leakage, the closed circulation loop liquid supply is restarted.

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