Mechanical seal system for automatic fluid infusion pump

Abstract

The invention discloses a mechanical seal system for an automatic fluid infusion pump, which comprises a plurality of groups of mechanical seals, a plurality of groups of seal circulating systems, an automatic fluid infusion system and a control system, the plurality of groups of mechanical seals are respectively arranged corresponding to a plurality of groups of serially connected pump sets, each group of mechanical seals comprises multi-stage seals, and the multi-stage seals are respectively arranged on multi-stage pumps of the serially connected pump sets; the liquid inlets and the liquid outlets of the plurality of groups of sealed circulating systems are correspondingly connected with the liquid outlets and the liquid inlets of the multi-stage seals respectively; the automatic liquid supplementing system comprises a liquid storage unit, a pumping unit and a plurality of groups of liquid supplementing units which are respectively connected with each group of sealing circulating systems; a liquid outlet of the liquid storage unit is connected with each group of liquid supplementing units through the pumping unit; the control system is connected with the liquid supplementing unit; according to different terminal pressure requirements, gradient pressure can be output in parallel, the pressure gradient of the sealing cavity in the operation of the series pump set can be effectively managed, and the overall efficiency and reliability of the system are improved.

Description

Technical Field

[0001] The present application relates to the technical field of mechanical seals, and in particular to a mechanical seal system for an automatic liquid replenishing pump. Background Art

[0002] Slurry pumps are widely used in the mining industry. They are mainly used to transport suspensions containing solid particles, which may be ore fragments mined from mines or by-products produced during processing. The design of slurry pumps must take into account the harsh environment in which they work, as they often need to handle high concentrations of abrasive and corrosive media. Mechanical seals (referred to as mechanical seals) are one of the important components of slurry pumps. Their main function is to prevent the fluid in the pump from leaking to the outside or foreign impurities from entering the pump.

[0003] The publication number CN204921968U provides a mechanical sealing system of a fully automatic regulating-circulating system, which includes a container, a safety valve, a liquid level sight glass, a liquid level transmitter, a discharge valve, an inlet sealing circulation circuit, an outlet sealing circulation circuit, a container pressure-reducing circuit and a container filling circuit. When all pipelines are connected, the liquid level transmitter is interlocked with the plunger pump and the electric stop valve at the same time. When the system is turned on, the plunger pump is automatically started, the electric stop valve is opened, and the isolation liquid is pumped into the system pipeline through the plunger pump and passed into the container. Until the liquid level reaches a high level, the liquid level transmitter sends a signal to stop the plunger pump and automatically close the electric stop valve. When the isolation liquid is consumed to a low level, the liquid level transmitter sends a signal again to replenish the liquid.

[0004] However, in a multi-stage pump system, due to the large pressure difference between pumps, the pressure management of the sealing system becomes particularly important. Improper pressure distribution may lead to seal failure, leakage and other problems, which in turn affects the overall performance and safety of the pump. Therefore, it is very necessary to reasonably design and implement a seal pressure gradient control strategy. Summary of the invention

[0005] The purpose of this application is to overcome the above technical deficiencies, propose a mechanical sealing system for an automatic fluid replenishment pump, and solve the technical problem that the fluid replenishment system in the prior art is difficult to apply to a multi-stage pump system.

[0006] In order to achieve the above technical objectives, this application adopts the following technical solutions: The present application provides a mechanical seal system for an automatic fluid replenishment pump, comprising: several groups of mechanical seals, several groups of sealing circulation systems, an automatic fluid replenishment system and a control system, wherein the several groups of mechanical seals are respectively arranged corresponding to several groups of serial pump groups, and each group of mechanical seals includes multi-stage seals, and the multi-stage seals are respectively arranged on the multi-stage pumps of the serial pump groups; the liquid inlets and liquid outlets of the several groups of sealing circulation systems respectively correspond to the liquid outlets and liquid inlets connected to the multi-stage seals, and are used for circulating, transporting and exchanging heat for the isolation liquid in the mechanical seals; the automatic fluid replenishment system comprises a liquid storage unit, a pumping unit and several groups of fluid replenishment units respectively connected to each group of sealing circulation systems, and the liquid outlets of the liquid storage units are connected to each group of fluid replenishment units through a pumping unit, so as to maintain the pipeline pressure in the fluid replenishment unit through the pumping unit; the control system is connected to the fluid replenishment unit, so as to control the fluid replenishment unit to supplement the set pressure to the corresponding sealing circulation system according to the pressure required by each stage of seal in the mechanical seal.

[0007] In some embodiments, as the pressure in the multi-stage pump of the series pump group gradually increases, the pressure value provided by the liquid replenishment unit to the sealed circulation system corresponding to the multi-stage pump gradually increases.

[0008] In some embodiments, each group of the sealed circulation system includes a heat exchanger, a first accumulator and a first circulation pump, the liquid inlet of the heat exchanger is connected to the liquid outlet of the mechanical seal through a first pipeline, the liquid outlet of the heat exchanger is connected to the liquid inlet of the mechanical seal through a second pipeline, and the heat exchanger is also provided with a cooling water inlet and a cooling water outlet for supplying coolant in and out; the first accumulator is connected to the second pipeline through a third pipeline, and the other end of the third pipeline is connected to the liquid replenishing unit through a first liquid inlet pipeline; the first circulation pump is installed on the second pipeline to provide driving force for the coolant to circulate between the heat exchanger and the mechanical seal.

[0009] In some embodiments, the sealed circulation system also includes a second liquid inlet pipeline, a gate valve, a quick connector and a first check valve. The second liquid inlet pipeline is connected to the third pipeline in parallel with the first liquid inlet pipeline. The third pipeline is sequentially provided with a quick connector, a gate valve and a first check valve along the flow direction of the coolant.

[0010] In some embodiments, the sealed circulation system also includes a first valve group, a first temperature transmitter, a sight glass, a first pressure gauge, a first pressure transmitter, a second valve group, a first ball valve, a first needle valve, a first flow transmitter, a second ball valve and a second needle valve. The first valve group, the first temperature transmitter and the sight glass are sequentially arranged in the first pipeline, and the first pressure gauge is connected to the first valve group; the first pressure transmitter is connected to the third pipeline through the second valve group; the first ball valve is connected to the third pipeline; the first needle valve, the first flow transmitter and the second ball valve are sequentially connected to the first liquid inlet pipeline; the first liquid inlet pipeline is also provided with a fourth pipeline respectively connected to the liquid inlet and outlet of the first liquid inlet pipeline, and the second needle valve is arranged in the fourth pipeline.

[0011] In some embodiments, each group of the pumps of the series pump group is provided with three stages, including a primary pump, a secondary pump and a tertiary pump respectively; each group of the multi-stage seals includes a primary seal, a secondary seal and a tertiary seal respectively, several groups of the primary seals are respectively installed on several groups of the primary pumps, several groups of the secondary seals are respectively installed on several groups of the secondary pumps, and several groups of the tertiary seals are respectively installed on several groups of the tertiary pumps; several groups of the sealing circulation systems include a primary sealing circulation system, a secondary sealing circulation system and a tertiary sealing circulation system respectively, the liquid inlet of the primary sealing circulation system is connected with the liquid outlet of several groups of the primary seals, and its liquid outlet is connected with the liquid inlet of several groups of the primary seals, the liquid inlet of the secondary sealing circulation system is connected with the liquid outlet of several groups of the secondary seals, and its liquid outlet is connected with the liquid inlet of several groups of the secondary seals, the liquid inlet of the tertiary sealing circulation system is connected with the liquid outlet of several groups of the tertiary seals, and its liquid outlet is connected with the liquid inlet of several groups of the tertiary seals,

[0012] In some embodiments, the liquid storage unit includes a water tank, the water tank is connected to the pumping unit via a fifth pipeline, and a filter is disposed on the fifth pipeline.

[0013] In some embodiments, the pumping unit includes a second circulation pump, two of which are provided, and the liquid inlets of the two second circulation pumps are connected to the water tank through two groups of the fifth pipelines respectively, and the liquid outlets of the two second circulation pumps are provided with a second check valve and a fourth ball valve in turn, and are connected to each group of the liquid replenishing units through a sixth pipeline, and the sixth pipeline is connected to a third valve group, a second pressure transmitter and a second accumulator.

[0014] In some embodiments, each group of the fluid replenishment units includes at least one pressure reducing branch structure, and the pressure reducing branch structure includes a first pressure reducing branch, a pressure relief pipeline, a pressure detection pipeline, a fifth ball valve, an automatic regulating valve, a third check valve, a sixth ball valve, a seventh ball valve, a first pressure relief valve, a fourth valve group and a second pressure gauge. The control system includes a controller and a control room. The first pressure reducing branch is respectively connected to a sealed circulation system and a pumping unit. A fifth ball valve, an automatic regulating valve, a pressure relief pipeline, a sixth ball valve, a pressure detection pipeline and a third check valve are sequentially arranged along the flow direction of the isolation fluid on the first pressure reducing branch. The automatic regulating valve has a nitrogen charging port. The automatic regulating valve of each group of the fluid replenishment units is connected to the control room through the controller, so that the automatic regulating valve can be adjusted through the control room and the controller to control the output pressure of the first pressure reducing branch; the seventh ball valve and the first pressure relief valve are arranged on the pressure relief pipeline; the fourth valve group and the second pressure gauge are arranged on the pressure detection pipeline.

[0015] In some embodiments, the water tank is provided with an inlet, an emptying port and a breathing filter, and an eighth ball valve and a ninth ball valve are installed on the inlet and the emptying port respectively; the water tank is also connected to a second flow transmitter through a tenth ball valve; the automatic liquid replenishing system also includes a safety pipeline, an eighth pipeline, a safety valve and a fourth needle valve, the safety pipeline is respectively connected to one end of the sixth pipeline and the water tank, the safety valve is installed on the safety pipeline, the eighth pipeline is connected to the other end of the sixth pipeline and the water tank, and the fourth needle valve is installed on the eighth pipeline.

[0016] Compared with the prior art, the mechanical seal system for the automatic refilling pump provided by the present application is provided with several groups of mechanical seals, several groups of sealing circulation systems and automatic refilling systems. The multi-stage seals of each group of mechanical seals are respectively arranged on the multi-stage pumps of the series pump group, and the isolation liquid is provided to the multi-stage seals through the sealing circulation system, and the isolation liquid in the mechanical seal is circulated and transported for heat exchange, so that a protective film is formed between the dynamic ring and the static ring of the pump to prevent the leakage of the transported medium and prevent the outside air or impurities from entering the sealing area; the automatic refilling system includes a liquid storage unit, a pumping unit and a refilling unit, and the pipeline pressure in the refilling unit is maintained by the pumping unit to ensure that the isolation liquid can flow normally, and at the same time it is conducive to the stable operation of the refilling unit; several groups of refilling units are respectively connected to each group of sealing circulation systems, and are controlled by the preset logic of the control system, and can output gradient pressure in parallel according to different terminal pressure requirements, solving the self-balancing problem of the cavity pressure and the sealing pressure difference of each unit in the operation of the series pump group. This allows the system to effectively manage the sealing cavity pressure gradient in the operation of the series pump group, and improves the overall efficiency and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It is a structural schematic diagram of a mechanical seal system for an automatic fluid infusion pump provided in an embodiment of the present application; Figure 2 It is a schematic diagram of the hierarchical connection structure of the mechanical seal system for the automatic fluid infusion pump provided in an embodiment of the present application; Figure 3 It is a structural schematic diagram of a sealing circulation system in a mechanical sealing system for an automatic liquid replenishing pump provided in an embodiment of the present application; Figure 4 It is a structural schematic diagram of an automatic liquid filling system in a mechanical sealing system for an automatic liquid filling pump provided in an embodiment of the present application; Figure 5 It is a structural schematic diagram of a liquid filling unit of an automatic liquid filling system in a mechanical sealing system for an automatic liquid filling pump provided in an embodiment of the present application; Figure 6 It is a three-dimensional structural schematic diagram of a sealing circulation system in a mechanical sealing system for an automatic liquid replenishing pump provided in an embodiment of the present application; Figure 7 It is a schematic diagram of the three-dimensional structure of the automatic fluid replenishment system in the mechanical sealing system for the automatic fluid replenishment pump provided in an embodiment of the present application.

[0018] Description of reference numerals: 1. Mechanical seal; 2. Sealed circulation system; 21. Heat exchanger; 22. First accumulator; 23. First circulation pump; 24. First valve group; 25. First temperature transmitter; 26. Sight glass; 27. First pressure gauge; 28. First pressure transmitter; 29. ​​Second valve group; 210. First ball valve; 211. First needle valve; 212. First flow transmitter; 213. Second ball valve; 214. Gate valve; 215. Quick connector; 216. First check valve; 217. Second needle valve; 201, first pipeline; 202, second pipeline; 203, third pipeline; 204, first liquid inlet pipeline; 205, second liquid inlet pipeline; 206, fourth pipeline; 3. Automatic liquid replenishment system; 31. Water tank; 32. Filter; 33. Second circulation pump; 34. Second check valve; 35. Fourth ball valve; 36. Third valve group; 37. Second pressure transmitter; 38. Second accumulator; 39. Fifth ball valve; 310. Automatic regulating valve; 311. Third check valve; 312. Sixth ball valve; 313. Seventh ball valve; 314. First pressure relief valve; 315. Fourth valve group; 316. Second pressure gauge; 317. Second pressure relief valve; 318. Eighth ball valve; 319. Ninth ball valve; 320. Breathing filter; 321. Tenth ball valve; 322. Second flow transmitter; 323. Safety valve; 324. Fourth needle valve; 301, fifth pipeline; 302, sixth pipeline; 303, first pressure reducing branch; 304, pressure relief pipeline; 305, pressure detection pipeline; 306, seventh pipeline; 307, safety pipeline; 308, eighth pipeline. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0020] In order to solve the technical problem that the fluid replenishment system is difficult to adapt to the multi-stage pump system, the present application provides a mechanical sealing system for an automatic fluid replenishment pump, which can output gradient pressure in parallel according to different terminal pressure requirements, and can effectively manage the pressure gradient of the sealing cavity during the operation of the series pump group, thereby improving the overall efficiency and reliability of the system.

[0021] See also Figures 1 to 7 The mechanical seal system for the automatic refilling pump includes: several groups of mechanical seals 1, several groups of sealing circulation systems 2, an automatic refilling system 3 and a control system. Several groups of the mechanical seals 1 are respectively arranged corresponding to several groups of serial pump groups, and each group of the mechanical seals 1 includes a multi-stage seal, which is respectively arranged on the multi-stage pump of the serial pump group; the liquid inlet and the liquid outlet of several groups of the sealing circulation system 2 correspond to the liquid outlet and the liquid inlet connected to the multi-stage seal, respectively, for circulating, transporting and exchanging heat for the isolation liquid in the mechanical seal 1; the automatic refilling system 3 includes a liquid storage unit, a pumping unit and several groups of refilling units respectively connected to each group of sealing circulation system 2, and the liquid outlet of the liquid storage unit is connected to each group of the refilling unit through the pumping unit to maintain the pipeline pressure in the refilling unit through the pumping unit; the control system is connected to the refilling unit to control the refilling unit to supplement the set pressure to the corresponding sealing circulation system 2 according to the pressure required by each stage of the seal in the mechanical seal 1.

[0022] In this solution, the multi-stage seals of each group of mechanical seals 1 are respectively arranged on the multi-stage pumps of the series pump group, and the isolation liquid is provided to the multi-stage seals through the sealing circulation system 2, and the isolation liquid in the mechanical seal 1 is circulated and transported for heat exchange, so that a protective film is formed between the dynamic ring and the static ring of the pump to prevent the leakage of the transported medium and prevent the outside air or impurities from entering the sealing area. The automatic liquid replenishment system 3 includes a liquid storage unit, a pumping unit and a liquid replenishment unit. The pipeline pressure in the liquid replenishment unit is maintained by the pumping unit to ensure that the isolation liquid can flow normally, and it is conducive to the stable operation of the liquid replenishment unit; in the multi-stage series pump group, the pressure of the medium in the pump will gradually increase, so that the seals of each stage of the pump need to gradually increase the pressure to balance the pressure difference between the pumps at each stage. In this solution, several groups of liquid replenishment units are connected to each group of sealing circulation systems 2 respectively, and the operating status is monitored in real time through the remote signal transmission equipment. The control system presets the logic control, so that according to the pressure required by the seals at each stage in the mechanical seal 1, the liquid replenishment unit is controlled to supplement the set pressure to the corresponding sealing circulation system 2, so that the system can effectively manage the pressure gradient of the sealing cavity during the operation of the series pump group, and improve the overall efficiency and reliability of the system.

[0023] It should be noted that, in this embodiment, the sealing pressure of each stage of the pump should be slightly higher than the pressure of the medium inside it, so that as the pressure in the multi-stage pump of the series pump group gradually increases, the pressure value provided by the liquid replenishment unit to the sealed circulation system 2 corresponding to the multi-stage pump gradually increases. When the sealing pressure is slightly higher than the pressure of the sealed medium, a pressure difference can be formed, which can prevent the sealed medium from leaking from the sealing surface. The pressure barrier formed at the sealing surface helps to maintain the integrity of the seal.

[0024] See also Figure 1 and Figure 2 , the branch pressure demand is associated with the pump cavity pressure, and the pump cavity pressure is associated with the pump outlet pressure. Taking the three-stage series as an example, the series pump pressure gradually increases from the first stage to the third stage. In order to ensure that the pressure between the sealing surfaces is moderate, the pressure value provided by the corresponding pressure reducing branch should be adaptively increased. For the convenience of explanation, in the following embodiments, the multi-stage pumps of each group of the series pump group are defined as a primary pump, a secondary pump and a tertiary pump; each group of the multi-stage seal and the sealing circulation system 2 are correspondingly set at three levels, and the multi-stage seals are defined as primary seals, secondary seals and tertiary seals, and several groups of the sealing circulation systems 2 are defined as primary sealing circulation systems, secondary sealing circulation systems and tertiary sealing circulation systems.

[0025] Among them, several groups of the first-level seals are respectively installed on several groups of the first-level pumps, several groups of the second-level seals are respectively installed on several groups of the second-level pumps, and several groups of the third-level seals are respectively installed on several groups of the third-level pumps; the liquid inlet of the first-level sealing circulation system is connected to the liquid outlet of several groups of the first-level seals, and its liquid outlet is connected to the liquid inlet of several groups of the first-level seals, the liquid inlet of the second-level sealing circulation system is connected to the liquid outlet of several groups of the second-level seals, and its liquid outlet is connected to the liquid inlet of several groups of the second-level seals, and the liquid inlet of the third-level sealing circulation system is connected to the liquid outlet of several groups of the third-level seals, and its liquid outlet is connected to the liquid inlet of several groups of the third-level seals. The multi-stage sealing circulation system 2 is pressurized by three fluid replenishing units respectively, so as to output gradient pressure in parallel, so as to ensure that the pressure at the mechanical seal 1 of each pump can prevent fluid leakage and avoid excessive pressure from damaging the seal, thereby ensuring the overall stability of the pump group.

[0026] See also Figure 1 , Figure 3 and Figure 6 The sealed circulation system 2 forms an external circulation loop, allowing the isolation fluid to circulate between the pump and the external circulation loop to achieve better cooling and lubrication effects. In this embodiment, each group of the sealed circulation system 2 includes a heat exchanger 21, a first accumulator 22 and a first circulation pump 23. The liquid inlet of the heat exchanger 21 is connected to the liquid outlet of the mechanical seal 1 through a first pipeline 201, and the liquid outlet of the heat exchanger 21 is connected to the liquid inlet of the mechanical seal 1 through a second pipeline 202. The heat exchanger 21 is also provided with a cooling water inlet and a cooling water outlet for the isolation fluid to enter and exit, which is used to circulate and replenish cooling water in the heat exchanger 21 through the cooling water inlet and the cooling water outlet to achieve heat exchange and cooling of the isolation fluid inside the heat exchanger 21. A spiral pipeline is provided in the heat exchanger 21, and the two ends of the spiral pipeline are respectively connected to the liquid inlet and the liquid outlet of the heat exchanger 21. The spiral pipeline is used to realize the circulation diversion and heat exchange and cooling of the isolation fluid, and at the same time, it is ensured that the isolation fluid in the sealed circulation system 2 is in a pressure environment.

[0027] The first accumulator 22 is connected to the second pipeline 202 via the third pipeline 203, and the other end of the third pipeline 203 is connected to the liquid replenishing unit via the first liquid inlet pipeline 204. The first circulation pump 23 is installed on the second pipeline 202, and is used to provide a driving force for the isolation liquid to circulate between the heat exchanger 21 and the mechanical seal 1. During implementation, the first circulation pump 23 provides a driving force to drive the isolation liquid to circulate between the mechanical seal 1, the first pipeline 201, the heat exchanger 21 and the second pipeline 202, and the isolation liquid used for pressure replenishment is replenished through the first liquid inlet pipeline 204 and the third pipeline 203.

[0028] Figure 3In the figure, A is the exhaust port, B is the flow direction of the isolation liquid from the mechanical seal; C is the flow direction of the isolation liquid to the mechanical seal, D is the cooling water inlet, E is the cooling water outlet, F is the drain port, G is the interface of the liquid replenishing unit; H is the nitrogen charging port; and I is the liquid replenishing port.

[0029] In order to optimize the piping structure of the sealed circulation system 2, further, in some possible embodiments, the sealed circulation system 2 also includes a first valve group 24, a first temperature transmitter 25, a sight glass 26, a first pressure gauge 27, a first pressure transmitter 28, a second valve group 29, a first ball valve 210, a first needle valve 211, a first flow transmitter 212, a second ball valve 213 and a second needle valve, etc. The first valve group 24, the first temperature transmitter 25 and the sight glass 26 are sequentially installed in the first pipeline 201, and the first A pressure gauge 27 is connected to the first valve group 24; the first pressure transmitter 28 is connected to the third pipeline 203 through the second valve group 29; the first ball valve 210 is connected to the third pipeline 203; the first needle valve 211, the first flow transmitter 212 and the second ball valve 213 are sequentially installed on the first liquid inlet pipeline 204; the first liquid inlet pipeline 204 is also installed with a fourth pipeline 206 connected to the liquid inlet and outlet of the first liquid inlet pipeline 204, and the second needle valve 217 is installed on the fourth pipeline 206. The first flow transmitter 212 can record the sealing liquid flow, and the daily internal leakage of the seal can be inferred through the flow change trend, so as to achieve early prediction.

[0030] It can be understood that the present solution is not limited to replenishing the pressure of the pipeline through only one pipeline. Therefore, multiple liquid inlet pipelines can be set in the embodiment to jointly replenish the pressure in the isolation liquid. Preferably, in the present embodiment, the sealed circulation system 2 also includes a second liquid inlet pipeline 205, a gate valve 214, a quick connector 215 and a first check valve 216. The second liquid inlet pipeline 205 is connected to the third pipeline 203 in parallel with the first liquid inlet pipeline 204. The third pipeline 203 is sequentially provided with a quick connector 215, a gate valve 214 and a first check valve 216 along the flow direction of the isolation liquid. The first liquid inlet pipeline 204 and the second liquid inlet pipeline 205 can be used to jointly or independently replenish the pressure in the circulation pipeline of the isolation liquid.

[0031] The pressure of the isolation liquid in the sealed circulation system 2 is maintained by the first accumulator 22. Preferably, the first accumulator 22 is a bladder accumulator. The use of a bladder accumulator can prevent the pressurized gas from contacting the isolation liquid, thereby avoiding the pressurized gas from being absorbed by the isolation liquid, so that the seal can be used in high-pressure operating conditions. The accumulator should be filled with pressurized gas first, and then with isolation liquid. The accumulator reaches the operating pressure by compressing the airbag with the isolation liquid. Leakage of the inner and outer seals will cause the pressure of the isolation system to decrease. Therefore, the initial charging pressure of the accumulator should be slightly higher than the required pressure. When the seal leaks, the pressure of the accumulator drops to the specified minimum pressure. At this time, the system should be refilled with isolation liquid to maximize the working volume of the isolation liquid, wherein the performance of the seal is monitored by detecting the pressure drop.

[0032] The flushing scheme can only work effectively if there is no gas or bubbles in the pipeline and the sealed cooler. When starting, the gas in the system must be exhausted. The sealed circulation system 2 is equipped with real-time monitoring and early warning of pressure, temperature, flow, etc. Once a large leak occurs in the seal, the control system will display an alarm at the first time, and then automatically switch to the liquid replenishment branch. A large amount of high-pressure flushing liquid is directly injected into the sealing cavity to block the slurry leakage point, prevent external air or other substances from entering the pump, and also prevent the slurry from leaking out.

[0033] See also Figure 1 , Figure 4 , Figure 5 and Figure 7 In this embodiment, the liquid storage unit includes a water tank 31, the pumping unit includes a second circulation pump 33, and each group of the liquid replenishing units includes at least one pressure reducing branch structure, and the pressure reducing branch structure includes a first pressure reducing branch 303, a pressure relief pipeline 304, a pressure detection pipeline 305, a fifth ball valve 39, an automatic regulating valve 310, a third check valve 311, a sixth ball valve 312, a seventh ball valve 313, a first pressure relief valve 314, a fourth valve group 315 and a second pressure gauge 316. The control system includes a controller and a control room.

[0034] Specifically, two second circulation pumps 33 are provided, and the liquid inlets of the two second circulation pumps 33 are connected to the water tank 31 through two groups of fifth pipelines 301 respectively. The filter 32 is installed at one end of the fifth pipeline 301 arranged in the water tank 31. The liquid outlets of the two second circulation pumps 33 are provided with a second check valve 34 and a fourth ball valve 35 in sequence, and are connected to the first pressure reducing branch 303 of each group of the liquid replenishing unit through a sixth pipeline 302. The sixth pipeline 302 is connected to a third valve group 36, a second pressure transmitter 37 and a second accumulator 38.

[0035] The first pressure reducing branch 303 is respectively connected to the sixth pipeline 302 and the liquid inlet pipeline of the sealed circulation system 2. The first pressure reducing branch 303 is provided with a fifth ball valve 39, an automatic regulating valve 310, a pressure relief pipeline 304, a sixth ball valve 312, a pressure detection pipeline 305 and a third check valve 311 in sequence along the flow direction of the isolation liquid. The automatic regulating valve 310 has a nitrogen charging port. The automatic regulating valve 310 of each group of the liquid replenishing unit is connected to the control room through a controller, so that the automatic regulating valve 310 can be adjusted through the control room and the controller to control the output pressure of the first pressure reducing branch 303; the pressure relief pipeline 304 is provided with a seventh ball valve 313 and a first pressure relief valve 314; the pressure detection pipeline 305 is provided with a fourth valve group 315 and a second pressure gauge 316.

[0036] In order to ensure the normal operation of the automatic liquid replenishment system 3, a suitable pressure level must be maintained. Preferably, the pressure is set to 4.0MPa. The water tank 31 stores the isolation liquid, and the two second circulation pumps 33 are used to supply liquid to the sealed circulation system 2, so that the total pressure is maintained at 4.0MPa. When the mechanical seal leaks, the first pressure transmitter 28 detects that the pressure is lower than a certain set value, and transmits the signal to the PLC control system to control the second circulation pump 33 to start automatically, and stop the pump when it reaches 4.0MPa. After the total pressure, multiple branches with different pressures are output in parallel to replenish the pressure to the sealed circulation system 2 respectively. Each branch (G1~G10) corresponds to a PCV automatic regulating valve 310, which is connected to the PLC control system room through a 24V electrical signal. The actuator of the valve is pneumatic. When the pressure needs to change, the control system room inputs an electrical signal, which is then converted into an analog signal and transmitted to the pneumatic actuator of the PCV valve. The starting mechanism pushes the valve stem to cause it to move, thereby realizing the pressure before and after the automatic regulating valve 310.

[0037] The isolation liquid in the water tank 31 increases the pressure of the liquid replenishing pipeline to a certain set value (4MPa) through the second circulation pump 33. When it reaches 4MPa, the pump stops working. When the pressure is lower than a certain set value (3.8MPa), the single pump starts to replenish the pressure to the set value (4MPa). If there is a large amount of mechanical leakage and the pressure is lower than a certain set value, the double pumps start to replenish the liquid. At the same time, the control system room monitors the signal, which proves that the mechanical seal 1 has failed and needs to be replaced.

[0038] When the automatic regulating valve 310 regulates the pressure, it mainly controls the flow of the fluid by changing the opening of the valve, thereby achieving the purpose of regulating the downstream pressure. The specific principle of the pneumatic automatic regulating valve 310 regulating the pressure is as follows: the automatic regulating valve 310 receives an air pressure signal from a control system (such as a PID controller). This signal is based on the comparison between the actual pressure value measured by the sensor and the preset pressure setting value. There is a diaphragm or piston inside the pneumatic actuator of the automatic regulating valve 310. When the air pressure signal is received, the diaphragm or piston will be displaced by the air pressure. The displacement of the diaphragm or piston is transmitted to the valve stem through a connecting rod or other transmission mechanism, thereby driving the valve core (or valve disc) to move up and down. The change in the position of the valve core determines the opening size of the valve. If the pressure needs to be increased, the valve opening is reduced; if the pressure needs to be reduced, the valve opening is increased. The system usually also includes a position feedback device, which can detect the actual position of the valve core and transmit the information back to the controller for closed-loop control to ensure that the actual pressure matches the set value.

[0039] Preferably, in the present application, there is no restriction on the number of decompression branch structures in each group of the infusion units, and the number of decompression branch structures connected to the corresponding sealed circulation system 2 can be increased sequentially according to the increase of the medium pressure in the first-stage pump to the third-stage pump; for example, the first-stage sealed circulation system is connected to two decompression branch structures, the second-stage sealed circulation system is connected to three decompression branch structures, and the third-stage sealed circulation system is connected to five decompression branch structures.

[0040] Furthermore, in some embodiments, the water tank 31 is provided with a liquid filling port, an emptying port and a breathing filter 320. Figure 4 In the figure, a is a liquid injection port, and b is an emptying port. The eighth ball valve 318 and the ninth ball valve 319 are installed on the liquid injection port and the emptying port, respectively. Isolation liquid can be added to the water tank 31 through the liquid injection port, and the isolation liquid can be emptied through the emptying hole to clean the water tank 31. The water tank 31 is also connected to the second flow transmitter 322 through the tenth ball valve 321. The first pressure reducing branch 303 is provided with a seventh pipeline 306 connected in parallel with the automatic regulating valve 310, and the seventh pipeline 306 is provided with a second pressure relief valve 317.

[0041] Furthermore, in some embodiments, the automatic fluid replenishment system 3 also includes a safety pipeline 307, an eighth pipeline 308, a safety valve 323 and a fourth needle valve 324, the safety pipeline 307 is respectively connected to one end of the sixth pipeline 302 and the water tank 31, the safety pipeline 307 is installed with the safety valve 323, the eighth pipeline 308 is connected to the other end of the sixth pipeline 302 and the water tank 31, and the fourth needle valve 324 is installed on the eighth pipeline 308. When the pipeline pressure of the automatic fluid replenishment system 3 is greater than the set value, the pressure can be relieved through the installed pipeline.

[0042] It should be noted that in this solution, there is no restriction on the valves and detection components installed on each pipeline. Valves, detection components and control structures can be installed arbitrarily on the main liquid supply pipeline and branch pipelines as needed.

[0043] The present application sets several groups of mechanical seals 1, several groups of sealing circulation systems 2 and automatic fluid replenishment systems 3. The multi-stage seals of each group of mechanical seals 1 are respectively set on the multi-stage pumps of the series pump group. The sealing circulation system 2 provides isolation liquid to the multi-stage seals, and the isolation liquid in the mechanical seal 1 is circulated and transported for heat exchange, so that a protective film is formed between the dynamic ring and the static ring of the pump to prevent leakage of the transported medium and prevent external air or impurities from entering the sealing area; the automatic fluid replenishment system 3 includes a liquid storage unit, a pumping unit and a fluid replenishment unit. The pipeline pressure in the fluid replenishment unit is maintained by the pumping unit to ensure that the isolation liquid can flow normally, and is conducive to the stable operation of the fluid replenishment unit; several groups of fluid replenishment units are respectively connected to each group of sealing circulation systems 2, and are controlled by the preset logic of the control system. According to different terminal pressure requirements, the gradient pressure can be output in parallel, which solves the self-balancing problem of the cavity pressure and the sealing fluid pressure difference of each unit in the operation of the series pump group. This allows the system to effectively manage the sealing cavity pressure gradient in the operation of the series pump group, and improves the overall efficiency and reliability of the system.

[0044] The sealing circulation system 2 is equipped with real-time monitoring and early warning of pressure, temperature, flow, etc. Once a large leak occurs in the seal, the control system will display an alarm at the first time, and then automatically switch to the fluid replenishment branch. A large amount of high-pressure flushing fluid is directly injected into the sealing cavity to block the slurry leakage point to prevent the slurry from flowing out and causing harm to people.

[0045] When working, firstly, it is necessary to accurately measure the inlet and outlet pressures of each level of pumps, and monitor these data in real time to understand the system pressure distribution, determine the supplementary pressure based on the monitored data, ensure that the sealing pressure is always higher than a certain value of the medium pressure, and ensure the stability of the system. The isolation fluid in the sealed circulation system 2 is transported by the second circulation pump 33 (gear pump), the heat exchanger 21 exchanges heat, and the accumulator stabilizes the pressure, which can maintain the pressure difference between the cavity of each mechanical seal 1 and the pump cavity at 0.3MPa self-circulation (as the pump continues to operate, the isolation fluid that acts as a lubricant between the sealing surfaces gradually loses, and the pressure of the sealed circulation system 2 gradually decreases. When it is lower than a certain set value, the PCV automatic regulating valve 310 of the replenishment unit opens to replenish the pressure to the sealed circulation system 2, and the valve automatically closes when the set value is reached).

[0046] In the description of the present application, it should be noted that the terms "upper" and "lower" 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 application and simplifying the description, rather than indicating or implying 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 application. Unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0047] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0048] The specific implementation methods of the present application described above do not constitute a limitation on the protection scope of the present application. Any other corresponding changes and modifications made according to the technical concept of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A mechanical sealing system for an automatic liquid replenishing pump, characterized in that: include: A plurality of groups of mechanical seals, wherein the plurality of groups of mechanical seals are respectively arranged corresponding to a plurality of groups of series pump groups, and each group of mechanical seals comprises a multi-stage seal, and the multi-stage seal is respectively arranged on the multi-stage pumps of the series pump group; Several groups of sealed circulation systems, wherein the liquid inlets and liquid outlets of the several groups of sealed circulation systems correspond to the liquid outlets and liquid inlets connected to the multi-stage seals, respectively, and are used for circulating, transporting and exchanging heat for the isolation liquid in the mechanical seals; An automatic liquid replenishing system, the automatic liquid replenishing system comprising a liquid storage unit, a pumping unit, and a plurality of groups of liquid replenishing units respectively connected to the groups of sealed circulation systems, wherein the liquid outlet of the liquid storage unit is connected to the groups of liquid replenishing units through the pumping unit, so as to maintain the pipeline pressure in the liquid replenishing unit through the pumping unit; as well as, A control system is connected to the fluid replenishing unit to control the fluid replenishing unit to replenish the set pressure to the corresponding sealing circulation system according to the pressure required by each level of sealing in the mechanical seal.

2. The mechanical seal system for the automatic fluid replenishment pump according to claim 1, characterized in that: As the pressure in the multi-stage pump of the series pump group gradually increases, the pressure value provided by the liquid replenishing unit to the sealed circulation system corresponding to the multi-stage pump gradually increases.

3. The mechanical seal system for the automatic fluid replenishment pump according to claim 1, characterized in that: Each of the sealed circulation systems comprises a heat exchanger, a first accumulator and a first circulation pump. The liquid inlet of the heat exchanger is connected to the liquid outlet of the mechanical seal through a first pipeline, and the liquid outlet of the heat exchanger is connected to the liquid inlet of the mechanical seal through a second pipeline. The heat exchanger is also provided with a cooling water inlet and a cooling water outlet for supplying coolant in and out; The first accumulator is connected to the second pipeline via a third pipeline, and the other end of the third pipeline is connected to the liquid replenishing unit via a first liquid inlet pipeline; The first circulation pump is installed on the second pipeline and is used to provide driving force for the coolant to circulate between the heat exchanger and the mechanical seal.

4. The mechanical seal system for the automatic liquid replenishment pump according to claim 3, characterized in that: The sealed circulation system also includes a second liquid inlet pipeline, a gate valve, a quick connector and a first check valve. The second liquid inlet pipeline is connected to the third pipeline in parallel with the first liquid inlet pipeline, and the third pipeline is provided with a quick connector, a gate valve and a first check valve in sequence along the flow direction of the coolant.

5. The mechanical seal system for the automatic liquid replenishment pump according to claim 4, characterized in that: The sealed circulation system also includes a first valve group, a first temperature transmitter, a sight glass, a first pressure gauge, a first pressure transmitter, a second valve group, a first ball valve, a first needle valve, a first flow transmitter, a second ball valve and a second needle valve. The first valve group, the first temperature transmitter and the sight glass are sequentially arranged in the first pipeline, and the first pressure gauge is connected to the first valve group; The first pressure transmitter is connected to the third pipeline through the second valve group; The first ball valve is connected to the third pipeline; The first needle valve, the first flow transmitter and the second ball valve are connected to the first liquid inlet pipeline in sequence; The first liquid inlet pipeline is also provided with a fourth pipeline connected to the liquid inlet and liquid outlet of the first liquid inlet pipeline respectively, and the second needle valve is provided on the fourth pipeline.

6. The mechanical seal system for the automatic fluid replenishment pump according to claim 1, characterized in that: Each group of the series pump groups has three pump stages, including a primary pump, a secondary pump and a tertiary pump; Each group of the multi-stage seals includes a primary seal, a secondary seal and a tertiary seal, several groups of the primary seals are installed on several groups of the primary pumps, several groups of the secondary seals are installed on several groups of the secondary pumps, and several groups of the tertiary seals are installed on several groups of the tertiary pumps; Several groups of the sealed circulation systems respectively include a primary sealed circulation system, a secondary sealed circulation system and a tertiary sealed circulation system. The liquid inlet of the primary sealed circulation system is connected to the liquid outlet of several groups of the primary seals, and its liquid outlet is connected to the liquid inlet of several groups of the primary seals. The liquid inlet of the secondary sealed circulation system is connected to the liquid outlet of several groups of the secondary seals, and its liquid outlet is connected to the liquid inlet of several groups of the secondary seals. The liquid inlet of the tertiary sealed circulation system is connected to the liquid outlet of several groups of the tertiary seals, and its liquid outlet is connected to the liquid inlet of several groups of the tertiary seals.

7. The mechanical seal system for the automatic fluid replenishment pump according to claim 1, characterized in that: The liquid storage unit comprises a water tank, the water tank is connected to the pumping unit via a fifth pipeline, and a filter is arranged on the fifth pipeline.

8. The mechanical seal system for the automatic fluid replenishment pump according to claim 7, characterized in that: The pumping unit includes a second circulating pump, and two second circulating pumps are provided. The liquid inlets of the two second circulating pumps are connected to the water tank through two groups of the fifth pipelines respectively, and the liquid outlets of the two second circulating pumps are provided with a second check valve and a fourth ball valve in sequence, and are connected to each group of the liquid replenishing units through a sixth pipeline, and the sixth pipeline is connected to a third valve group, a second pressure transmitter and a second accumulator.

9. The mechanical seal system for the automatic fluid replenishment pump according to claim 8, characterized in that: Each group of the liquid replenishing units includes at least one pressure reducing branch structure, and the pressure reducing branch structure includes a first pressure reducing branch, a pressure relief pipeline, a pressure detection pipeline, a fifth ball valve, an automatic regulating valve, a third check valve, a sixth ball valve, a seventh ball valve, a first pressure relief valve, a fourth valve group and a second pressure gauge. The control system includes a controller and a control room. The first pressure reducing branch is respectively connected to the sealing circulation system and the pumping unit. A fifth ball valve, an automatic regulating valve, a pressure relief pipeline, a sixth ball valve, a pressure detection pipeline and a third check valve are sequentially arranged along the flow direction of the isolation liquid on the first pressure reducing branch. The automatic regulating valve has a nitrogen charging port. The automatic regulating valve of each group of the liquid replenishing unit is connected to the control room through a controller, so that the automatic regulating valve can be adjusted through the control room and the controller, thereby controlling the output pressure of the first pressure reducing branch; The pressure relief pipeline is provided with a seventh ball valve and a first pressure relief valve; The pressure detection pipeline is provided with a fourth valve group and a second pressure gauge.

10. The mechanical sealing system for the automatic liquid replenishing pump according to claim 9, characterized in that: The water tank is provided with a liquid injection port, an emptying port and a breathing filter, and an eighth ball valve and a ninth ball valve are respectively installed on the liquid injection port and the emptying port; the water tank is also connected to a second flow transmitter through the tenth ball valve; The automatic liquid replenishment system also includes a safety pipeline, an eighth pipeline, a safety valve and a fourth needle valve. The safety pipeline is respectively connected to one end of the sixth pipeline and the water tank, and the safety valve is installed on the safety pipeline. The eighth pipeline connects the other end of the sixth pipeline and the water tank, and the fourth needle valve is installed on the eighth pipeline.

Images