Tandem type double-end-face mechanical sealing device

Abstract

The invention provides a tandem type double-end-face mechanical sealing device which comprises a shell, a rotating shaft, a cooling system and an adjusting system, the rotating shaft is rotatably arranged in the shell, the shell comprises a first sealing cavity and a second sealing cavity, the first sealing cavity is communicated with a liquid storage tank, and the second sealing cavity is communicated with the liquid storage tank. The cooling system comprises a cooler arranged in the second sealing cavity, the cooler communicates with the liquid storage tank, and the partition system communicates with the second sealing cavity and is configured to be opened when the pressure in the second sealing cavity is lower than a preset value and closed when the pressure in the second sealing cavity reaches or exceeds the preset value. The adjusting system is used for adjusting the pressure of the first sealing cavity and the second sealing cavity. According to the tandem type double-end-face mechanical sealing device, reliable standby application of the second-stage seal in the low-pressure or non-pressure state is achieved, working pressure can be accurately established when needed, and therefore the redundancy and operation stability of the tandem type double-end-face mechanical sealing device are guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical sealing devices, in particular to a series connection type double-end-face mechanical sealing device. BACKGROUND

[0002] The series connection type double-end-face mechanical sealing device is commonly used in sealing occasions of high pressure, high risk or easily-leaking medium. When the sealing object is single medium, the series connection type double-end-face mechanical sealing device adopts one-use-one-backup or pressure division working mode. In the one-use-one-backup mode, the first level sealing bears the whole pressure of the sealed medium, and the second level sealing is in low pressure standby state. In the pressure division working mode, the first level sealing and the second level sealing bear different working pressures in proportion.

[0003] In some special working conditions, only the sealed medium is allowed to cool the sealing end face in order to meet the process restrictions.

[0004] In the related art, the cooling medium directly acts on the second level sealing end face. Since the cooling medium is the sealed medium with pressure, the second level sealing is actually in a pressure working state. This leads to the fact that the second level sealing cannot maintain the low pressure or pressure-free standby state as designed, the one-use-one-backup or pressure division working mode function fails, the redundancy of the sealing system is reduced, and the second level sealing is prone to premature wear, which reduces the overall sealing reliability and safety of the device. SUMMARY

[0005] The present application provides a series connection type double-end-face mechanical sealing device to solve the defect that the second level sealing is forced to be in a pressure working state due to the direct action of the cooling medium in the prior art, which leads to the failure of the one-use-one-backup or pressure division mode function, and to achieve the reliable standby of the second level sealing in a low pressure or pressure-free state, and to accurately establish the working pressure when needed, thereby ensuring the redundancy and stable operation of the series connection type double-end-face mechanical sealing device.

[0006] The present application provides a series connection type double-end-face mechanical sealing device, comprising: a housing and a rotating shaft, the rotating shaft is rotatably arranged in the housing, the housing comprises a first sealing cavity and a second sealing cavity arranged in sequence along the axial direction of the rotating shaft, and the first sealing cavity is in communication with the liquid storage tank; a cooling system comprising a cooler arranged in the second sealing cavity, the cooler is in communication with the liquid storage tank, and the cooling medium in the cooler exchanges heat with the second sealing medium in the second sealing cavity; a partition system in communication with the second sealing cavity, configured to open when the pressure in the second sealing cavity is lower than a preset value, and to close when the pressure in the second sealing cavity reaches or exceeds the preset value; an adjusting system for adjusting the pressure of the first sealing cavity and the second sealing cavity; The series type double-end-face mechanical seal device comprises a one-to-one standby mode and a partial pressure mode, in the one-to-one standby mode, the cutoff system is operated and the adjusting system is closed; in the partial pressure mode, the cutoff system is closed and the adjusting system is operated.

[0007] In some embodiments, the cooling system comprises: an inlet pipe, one end of which is communicated with the liquid storage tank and the other end of which is communicated with the first sealing cavity and the cooler through two branch pipes respectively; a return pipe, one end of which is communicated with the cooler and the other end of which is communicated with the liquid storage tank.

[0008] In some embodiments, the adjusting system comprises: a first adjusting pipe, which is communicated with the first sealing cavity and is provided with a first adjusting valve thereon; a second adjusting pipe, which is communicated with the second sealing cavity and is provided with a second adjusting valve thereon; a total adjusting pipe, which is communicated with the first adjusting pipe and the second adjusting pipe and is provided with a total adjusting valve thereon.

[0009] In some embodiments, the cutoff system comprises: a discharge pipe, which is communicated with the second sealing cavity; a cutoff valve, which is arranged on the discharge pipe; a first pressure gauge, which is used for monitoring the pressure of the second sealing medium in the second sealing cavity.

[0010] In some embodiments, the cooling system comprises: a coarse filter and a fine filter, which are arranged on the inlet pipe in sequence and are used for filtering impurities in the cooling medium.

[0011] In some embodiments, the cooling system comprises, which are arranged on the inlet pipe: a water pump, which is used for providing circulating power for the cooling medium; a flow meter, which is used for monitoring the flow of the cooling medium; a second pressure gauge, which is used for detecting the pressure in the inlet pipe.

[0012] In some embodiments, the two branch pipes comprise: a first branch pipe, which communicates the inlet pipe with the first sealing cavity and is provided with a first inlet valve thereon; a second branch pipe, which communicates the inlet pipe with the cooler and is provided with a second inlet valve thereon.

[0013] In some embodiments, the cooling system comprises: a stop valve, which is arranged on the return pipe and is used for controlling the opening and closing of the return pipe.

[0014] In some embodiments, the cooling system comprises: a temperature gauge for detecting the temperature of the second sealing medium in the second sealing cavity.

[0015] In some embodiments, the tandem double mechanical seal device comprises: two sealing assemblies respectively arranged in the first sealing cavity and the second sealing cavity, and sealingly matched with the rotating shaft.

[0016] The tandem double mechanical seal device of the embodiment of the present application uses the cooler to isolate the cooling medium from the second sealing medium in the second sealing cavity, and the cooling process does not interfere with the pressure state of the second sealing cavity. Thus, the second-stage seal can be kept standby under low pressure or no pressure, and the required working pressure can be accurately established when needed, so that the one-use-one-standby or pressure division working mode can be reliably realized. Moreover, the tandem double mechanical seal device of the embodiment of the present application helps to maintain the redundancy of the sealing system and prolong the service life of the second-stage seal, thereby improving the overall sealing stability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor based on these drawings.

[0018] Figure 1 is a structural schematic diagram of the tandem double mechanical seal device provided by the present application.

[0019] Reference signs: 200, liquid storage tank; 100, tandem double mechanical seal device; 1, housing; 11, first sealing cavity; 12, second sealing cavity; 2, rotating shaft; 3, cooling system; 31, cooler; 32, inlet pipe; 321, coarse filter; 322, fine filter; 323, water pump; 324, flow meter; 325, second pressure gauge; 33, first branch pipe; 331, first inlet valve; 34, second branch pipe; 341, second inlet valve; 35, return pipe; 351, stop valve; 36, temperature gauge; 4, partition system; 41, discharge pipe; 42, partition valve; 43, first pressure gauge; 5. Regulating system; 51. First regulating pipe; 511. First regulating valve; 52. Second regulating pipe; 521. Second regulating valve; 53. Main regulating pipe; 531. Main regulating valve; 6. Sealing assembly; 61. Dynamic ring; 62. Stationary ring. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] like Figure 1 As shown, the series double-end mechanical seal device 100 of this embodiment includes a housing 1, a rotating shaft 2, a cooling system 3, and an adjustment system 5.

[0022] The rotating shaft 2 is rotatably disposed inside the housing 1. The housing 1 includes a first sealing cavity 11 and a second sealing cavity 12 arranged sequentially along the axial direction of the rotating shaft 2. The first sealing cavity 11 is connected to the liquid storage tank 200.

[0023] The cooling system 3 includes a cooler 31 disposed in the second sealed cavity 12. The cooler 31 is connected to the liquid storage tank 200, and the cooling medium in the cooler 31 exchanges heat with the second sealing medium in the second sealed cavity 12.

[0024] The isolation system 4 is connected to the second sealing cavity 12 and is configured to open when the pressure in the second sealing cavity 12 is lower than a preset value and close when the pressure in the second sealing cavity 12 reaches or exceeds the preset value.

[0025] The regulating system 5 is used to regulate the pressure of the first sealing chamber 11 and the second sealing chamber 12.

[0026] The series-connected double-end mechanical seal device 100 includes a one-in-one-standby mode and a pressure-dividing mode. In the one-in-one-standby mode, the isolation system 4 is in operation and the regulating system 5 is off. In the pressure-dividing mode, the isolation system 4 is off and the regulating system 5 is in operation.

[0027] The housing 1 includes a first sealing cavity 11 and a second sealing cavity 12, thus forming a two-stage seal. Before the tandem double-end mechanical seal device 100 operates, the second sealing cavity 12 is filled with a second sealing medium to expel internal air. The first-stage seal is the primary seal; whether in a one-in-one-out mode or a pressure-dividing mode, the pressure in the first sealing cavity 11 is greater than the pressure in the second sealing cavity 12. Therefore, a small amount of the first sealing medium may leak into the second sealing cavity 12.

[0028] The series-connected double-end mechanical seal device 100 is connected to the liquid storage tank 200 for storing the sealed medium, and the first sealing cavity 11 is in communication with the liquid storage tank 200. The first sealing medium in the first sealing cavity 11 is the same as the sealed medium in the liquid storage tank 200. The second sealing cavity 12 is not in communication with the first sealing cavity 11, and the medium in the second sealing cavity 12 is the second sealing medium.

[0029] After entering the cooling system 3, the sealing medium becomes the cooling medium. The cooler 31 is located in the second sealing cavity 12 and is connected to the liquid storage tank 200. The cooling medium flowing inside the cooler and the second sealing medium in the second sealing cavity 12 cool the second sealing end face through heat exchange. The two do not mix directly.

[0030] In the one-in-one-outstand mode, the first sealing chamber 11 bears all the sealing pressure, while the second sealing chamber 12 is in a low-pressure standby state. At this time, the isolation system 4 operates while the regulating system 5 is closed, discharging a small amount of medium leaking from the first sealing chamber 11 to the second sealing chamber 12 to prevent the pressure in the second sealing chamber 12 from rising. The cooler 31 independently cools the second sealing chamber 12, with the cooling medium coming from the storage tank 200, but without changing the pressure state of the second sealing chamber 12. When the first-stage seal fails or the leakage increases, causing the pressure in the second sealing chamber 12 to rise to a preset value, the isolation system 4 automatically closes, the second sealing chamber 12 builds up pressure and begins operation, achieving the switchover to standby function.

[0031] In the pressure-sharing mode, the isolation system 4 remains closed, and the regulating system 5 controls the flow of the medium between the two sealing chambers so that the first sealing chamber 11 and the second sealing chamber 12 share the sealing pressure according to a set ratio. At the same time, the cooler 31 still provides independent cooling to the second sealing chamber 12.

[0032] In related technologies, the cooling medium acts directly on the end face of the second-stage seal. Since the cooling medium is pressurized and being sealed, the second-stage seal is actually operating under pressure. This causes the second-stage seal to fail to maintain the designed low-pressure or unpressurized standby state, resulting in the failure of the one-in-use-one-standby or pressure-divided working mode. The redundancy of the sealing system is reduced, leading to premature wear of the second-stage seal and a decrease in the overall sealing reliability and safety of the device.

[0033] In the tandem double-end mechanical seal device 100 of this invention, the cooler 31 isolates the cooling medium from the second sealing medium in the second sealing cavity 12, ensuring that the cooling process does not interfere with the pressure state of the second sealing cavity 12. Therefore, the second-stage seal can remain on standby under low or no pressure, and can also accurately establish the required working pressure when needed, thus reliably achieving a one-in-one-out or pressure-dividing working mode. Furthermore, the tandem double-end mechanical seal device 100 of this invention helps maintain the redundancy of the sealing system, extends the service life of the second-stage seal, and thus improves the overall sealing stability of the device.

[0034] In some embodiments, the cooling system 3 includes an inlet pipe 32 and a return pipe 35.

[0035] One end of the inlet pipe 32 is connected to the liquid storage tank 200, and the other end is connected to the first sealing cavity 11 and the cooler 31 through two branch pipes respectively.

[0036] One end of the return pipe 35 is connected to the cooler 31, and the other end is connected to the liquid storage tank 200.

[0037] In this embodiment, the cooling medium flows out of the storage tank 200 and is transported through the inlet pipe 32. At the end of the inlet pipe 32, it is divided into two paths: one path enters the first sealing cavity 11 through the first branch pipe 33 to directly cool the first sealing end face; the other path enters the cooler 31 located in the second sealing cavity 12 through the second branch pipe 34, completes heat exchange in the cooler 31, and then returns to the storage tank 200 through the return pipe 35 to form a closed loop.

[0038] The series double-end mechanical seal device 100 of this invention sets the cooling system 3 as a closed circulation loop, so that the cooling medium can complete heat exchange without entering the second sealing cavity 12, thereby achieving indirect cooling of the second-stage seal. This ensures that the pressure in the second sealing cavity 12 depends only on the sealing condition itself and is not affected by the flow or pressure of the cooling medium, providing a structural basis for reliable switching and stable operation of the one-in-one-out mode and the pressure-dividing mode.

[0039] In some embodiments, the regulating system 5 includes a first regulating tube 51, a second regulating tube 52, and a main regulating tube 53.

[0040] The first regulating pipe 51 is connected to the first sealing cavity 11, and a first regulating valve 511 is provided on it.

[0041] The second regulating pipe 52 is connected to the second sealing cavity 12, and a second regulating valve 521 is provided on it.

[0042] The main regulating pipe 53 is connected to both the first regulating pipe 51 and the second regulating pipe 52, and a main regulating valve 531 is provided on it.

[0043] In this embodiment, the regulating system 5 forms a pressure control loop through three interconnected pipes: When the series-connected double-end mechanical seal device 100 switches from the one-in-one-out mode to the pressure-dividing mode, first close the main regulating valve 531, then open the first regulating valve 511, and then slowly open the second regulating valve 521. At this time, the first sealing medium will flow into the second sealing chamber 12 through the first regulating valve 511 and the second regulating valve 521, causing the pressure of the second sealing medium to gradually increase. When it rises to the preset pressure, the second regulating valve 521 can be quickly closed, and then the first regulating valve 511 can be closed. At this time, the conversion from the one-in-one-out mode to the pressure-dividing mode is completed.

[0044] When the series-connected double-end mechanical seal device 100 switches from the pressure-dividing mode to the one-in-one-out-of-service mode, if it is necessary to reduce the working pressure of the second sealing medium or adjust the working mode to the one-in-one-out-of-service mode, ensure that the first regulating valve 511 is closed, then open the second regulating valve 521, and then open the main regulating valve 531 to release the pressure of the sealing medium in the second-stage sealing chamber. When the pressure in the second sealing chamber 12 returns to the initial value, the main regulating valve 531 can be quickly closed, and then the second regulating valve 521 can be closed. At this time, the conversion from the pressure-dividing mode to the one-in-one-out-of-service mode is completed.

[0045] The series double-end mechanical seal device 100 of this invention utilizes a three-way adjustment structure composed of a first adjustment pipe 51, a second adjustment pipe 52 and a main adjustment pipe 53 to flexibly adjust the pressure relationship between the two sealing chambers without changing the main sealing structure, so as to establish a pressure-dividing mode.

[0046] In some embodiments, the isolation system 4 includes a drain pipe 41, an isolation valve 42, and a first pressure gauge 43.

[0047] The discharge pipe 41 is connected to the second sealing cavity 12.

[0048] Isolation valve 42 is located on discharge pipe 41.

[0049] The first pressure gauge 43 is used to monitor the pressure of the second sealing medium in the second sealing cavity 12.

[0050] In this embodiment, a shut-off valve 42 and a first pressure gauge 43 are installed on the discharge pipe 41, with the first pressure gauge 43 located upstream of the shut-off valve 42.

[0051] During normal operation, the isolation valve 42 remains open, discharging the medium that leaks a small amount from the first sealing chamber 11 into the second sealing chamber 12, and maintaining the second sealing chamber 12 in a low-pressure standby state. When the first-stage seal fails, causing the leakage to increase and the pressure in the second sealing chamber 12 to rise to a preset threshold, the isolation valve 42 is closed according to the reading of the first pressure gauge 43, so that the second sealing chamber 12 is sealed and the working pressure is established.

[0052] The series double-end mechanical seal device 100 of this invention, through the cooperation of the discharge pipe 41, the isolation valve 42 and the first pressure gauge 43, realizes real-time perception and automatic response to the pressure status of the second sealing chamber 12. While ensuring that the second-stage seal is in a standby state for a long time, it also ensures that it can be put into sealing work in time when the main seal fails, thereby improving the functional redundancy of the sealing system.

[0053] In some embodiments, the cooling system 3 includes a coarse filter 321 and a fine filter 322.

[0054] The coarse filter 321 and the fine filter 322 are sequentially arranged in the inlet pipe 32 to filter impurities in the cooling medium.

[0055] In this embodiment, after the cooling medium flows out of the storage tank 200, it first passes through the coarse filter 321 for preliminary filtration to remove larger particulate impurities, and then enters the fine filter 322 for fine filtration to ensure the cleanliness of the medium entering the first sealing cavity 11 and the cooler 31, and to prevent impurities from scratching the sealing surface or blocking the cooling channel.

[0056] The series-type double-end mechanical seal device 100 of this invention ensures the cleanliness of the cooling medium by sequentially arranging a coarse filter 321 and a fine filter 322 on the inlet pipe 32, reducing the risk of seal failure due to particulate contamination. Especially when the sealed medium is used as the cooling source, it helps to maintain the long-term stable operation of the two-stage sealing end faces.

[0057] In some embodiments, the cooling system 3 includes a water pump 323, a flow meter 324, and a second pressure gauge 325 disposed on the inlet pipe 32.

[0058] Water pump 323 is used to provide circulating power for the cooling medium.

[0059] The flow meter 324 is used to monitor the flow rate of the cooling medium.

[0060] The second pressure gauge 325 is used to detect the pressure inside the inlet pipe 32.

[0061] In this embodiment, the water pump 323 drives the cooling medium to circulate within the cooling system 3; the flow meter 324 reflects the circulation volume of the cooling medium in real time, making it easy to determine whether the cooling capacity is sufficient; the second pressure gauge 325 monitors the main pressure of the inlet pipe 32, providing a reference for the operating status of the series double-end mechanical seal device 100.

[0062] The series-connected double-end mechanical seal device 100 of this invention integrates a water pump 323, a flow meter 324, and a second pressure gauge 325 to achieve synchronous monitoring of the power, flow rate, and pressure of the cooling circuit, providing a parameter basis for the reliable operation of the cooling system 3. At the same time, the pumping capacity of the water pump 323 can be adjusted according to the actual working conditions to ensure that the two-stage sealing end faces obtain a continuous and stable cooling effect.

[0063] In some embodiments, the two branches include a first branch 33 and a second branch 34.

[0064] The first branch pipe 33 connects the inlet pipe 32 and the first sealing cavity 11, and is equipped with a first inlet valve 331.

[0065] The second branch pipe 34 connects the inlet pipe 32 and the cooler 31, and is equipped with a second inlet valve 341.

[0066] In this embodiment, the first branch pipe 33 and the second branch pipe 34 branching off from the end of the inlet pipe 32 lead to the first sealing cavity 11 and the cooler 31, respectively. By controlling the opening and closing states of the first inlet valve 331 and the second inlet valve 341, liquid can be selectively supplied to the first sealing cavity 11 or to the cooler 31, or they can be opened simultaneously to achieve dual-path cooling.

[0067] The tandem double-end mechanical seal device 100 of this invention adopts a double-branch pipe structure with an independent control valve, which allows the direct cooling of the first-stage seal and the indirect cooling of the second-stage seal to operate independently yet collaboratively in the flow path, avoiding pressure interference caused by cooling path coupling, and providing flexible support for the cooling needs of the two-stage seals under different working modes.

[0068] In some embodiments, the cooling system 3 includes a shut-off valve 351.

[0069] The shut-off valve 351 is located on the return pipe 35 and is used to control the opening and closing of the return pipe 35.

[0070] In this embodiment, the shut-off valve 351 is installed on the return pipe 35 between the outlet of the cooler 31 and the liquid storage tank 200. It can be manually or automatically closed during the start-up, maintenance or abnormal operation of the cooling system 3 to cut off the return path of the cooling medium and facilitate the operation of the cooling system 3.

[0071] The series double-end mechanical seal device 100 of this invention enhances the operational flexibility and safety of the cooling system 3 by setting a shut-off valve 351 in the return pipe 35, and supports independent control and maintenance of the cooling circuit without affecting the pressure state of the second sealing chamber 12.

[0072] In some embodiments, the cooling system 3 includes a thermometer 36.

[0073] The thermometer 36 is used to detect the temperature of the second sealing medium inside the second sealing cavity 12.

[0074] In this embodiment, the thermometer 36 is directly installed on the housing 1 of the second sealing cavity 12 to measure the temperature of the second sealing medium in real time, reflecting the heat load status of the second sealing end face; the temperature data can be used to determine whether the heat exchange efficiency of the cooler 31 is normal, or as a basis for system early warning.

[0075] The series double-end mechanical seal device 100 of this invention monitors the medium temperature of the second sealing cavity 12 by setting a thermometer 36, which provides direct feedback on the indirect cooling effect, helps to detect abnormalities such as insufficient cooling or overheating in a timely manner, and ensures the stability of the second-stage seal in standby or working state.

[0076] In some embodiments, the tandem double-end mechanical seal device 100 includes two sealing components 6. The two sealing components 6 are respectively disposed in the first sealing cavity 11 and the second sealing cavity 12, and both are in sealing cooperation with the rotating shaft 2.

[0077] In this embodiment, the sealing component 6 in the first sealing cavity 11 serves as the main seal and bears the main sealing pressure; the sealing component 6 in the second sealing cavity 12 serves as a backup or pressure-dividing seal.

[0078] Both sealing assemblies 6 are arranged around the same rotating shaft 2, forming a double-end face sealing structure connected in series along the axial direction, which together prevents the medium from leaking out. The sealing assembly 6 includes a dynamic ring 61 and a stationary ring 62.

[0079] The tandem double-end mechanical seal device 100 of this invention constructs a physically isolated double-level sealing barrier by setting sealing components 6 that cooperate with the rotating shaft 2 in two independent sealing cavities.

[0080] In other embodiments, a first heat exchanger is provided in the first sealing cavity 11, the first branch pipe 33 is connected to the first heat exchanger, and the return pipe 35 is connected to the first heat exchanger, thereby ensuring that the pressure state in the first sealing cavity 11 is not affected by the pressure of the cooling medium.

[0081] In other embodiments, the valve may be designed as a manual valve, an electrically controlled valve, or a valve that can be both manually and electrically controlled.

[0082] In other embodiments, the flow meter 324, the first pressure gauge 43, the second pressure gauge 325, and the thermometer 36 can be configured as either local instruments only or local + remote instruments, depending on actual needs.

[0083] These instruments are local instruments, meaning they only display measured values ​​at the installation location of the series double-end mechanical seal device 100 for direct reading by on-site operators and do not have remote transmission capabilities. Local + remote instruments mean that these instruments can not only display data on-site, but also transmit measurement signals to a remote control system to achieve remote monitoring and automated control.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A series-connected double-end-face mechanical seal device, connected to a liquid storage tank (200) storing the sealed medium, characterized in that, include: The housing (1) and the rotating shaft (2) are rotatably disposed inside the housing (1). The housing (1) includes a first sealing cavity (11) and a second sealing cavity (12) arranged sequentially along the axial direction of the rotating shaft (2). The first sealing cavity (11) is in communication with the liquid storage tank (200). The cooling system (3) includes a cooler (31) disposed in the second sealed cavity (12), the cooler (31) being connected to the liquid storage tank (200), and the cooling medium in the cooler (31) exchanging heat with the second sealing medium in the second sealed cavity (12); The isolation system (4), which is connected to the second sealing cavity (12), is configured to open when the pressure in the second sealing cavity (12) is lower than a preset value, and to close when the pressure in the second sealing cavity (12) reaches or exceeds the preset value; The regulating system (5) is used to regulate the pressure of the first sealing cavity (11) and the second sealing cavity (12); The series-connected double-end mechanical seal device includes a one-in-one-standby mode and a pressure-dividing mode. In the one-in-one-standby mode, the isolation system (4) is in operation and the regulating system (5) is off. In the pressure-dividing mode, the isolation system (4) is off and the regulating system (5) is in operation.

2. The tandem double-end mechanical seal device according to claim 1, characterized in that, The cooling system (3) includes: The inlet pipe (32) is connected at one end to the liquid storage tank (200), and at the other end to the first sealing cavity (11) and the cooler (31) respectively through two branch pipes; The return pipe (35) is connected at one end to the cooler (31) and at the other end to the liquid storage tank (200).

3. The tandem double-end mechanical seal device according to claim 1, characterized in that, The regulating system (5) includes: The first regulating pipe (51) is connected to the first sealing cavity (11) and is provided with a first regulating valve (511). The second regulating pipe (52) is connected to the second sealing cavity (12), and a second regulating valve (521) is provided on it. The main regulating pipe (53) is connected to both the first regulating pipe (51) and the second regulating pipe (52), and a main regulating valve (531) is provided on it.

4. The tandem double-end mechanical seal device according to any one of claims 1-3, characterized in that, The partition system (4) includes: The discharge pipe (41) is connected to the second sealing cavity (12); Isolation valve (42) is provided on the discharge pipe (41); The first pressure gauge (43) is used to monitor the pressure of the second sealing medium in the second sealing cavity (12).

5. The tandem double-end mechanical seal device according to claim 2, characterized in that, The cooling system (3) includes: A coarse filter (321) and a fine filter (322) are sequentially disposed in the inlet pipe (32) for filtering impurities in the cooling medium.

6. The tandem double-end mechanical seal device according to claim 2, characterized in that, The cooling system (3) includes a component disposed on the inlet pipe (32): A water pump (323) is used to provide circulating power for the cooling medium; A flow meter (324) is used to monitor the flow rate of the cooling medium; The second pressure gauge (325) is used to detect the pressure inside the inlet pipe (32).

7. The tandem double-end mechanical seal device according to claim 2, characterized in that, The two branch pipes include: The first branch pipe (33) connects the inlet pipe (32) and the first sealing cavity (11), and is provided with a first inlet valve (331). The second branch pipe (34) connects the inlet pipe (32) and the cooler (31), and is equipped with a second inlet valve (341).

8. The tandem double-end mechanical seal device according to any one of claims 5-7, characterized in that, The cooling system (3) includes: A shut-off valve (351) is provided on the return pipe (35) for controlling the opening and closing of the return pipe (35).

9. The tandem double-end mechanical seal device according to claim 1, characterized in that, The cooling system (3) includes: A thermometer (36) is used to detect the temperature of the second sealing medium inside the second sealing cavity (12).

10. The tandem double-end mechanical seal device according to claim 1, characterized in that, The series-connected double-end-face mechanical seal device includes: Two sealing components are respectively located in the first sealing cavity (11) and the second sealing cavity (12), and both are sealed to the rotating shaft (2).

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