Submersible pump mechanical sealing mechanism capable of switching along with rotating speed

Abstract

The invention discloses a submersible pump mechanical sealing mechanism capable of switching along with rotating speed, which belongs to the technical field of fluid machinery and comprises a main shaft, a first mechanical seal, a second mechanical seal, a hydraulic driving component, an auxiliary impeller component and a fluid passage. The hydraulic driving assembly comprises a hydraulic cylinder body, a piston, a piston rod and a hydraulic cylinder spring, a hydraulic cylinder left cavity and a hydraulic cylinder right cavity are separated by the piston, one end of the piston rod is connected with the piston, and the other end of the piston rod is connected with the second static ring. When the submersible pump is at medium-low rotating speed, only the first mechanical seal works; and at a high rotating speed, the first mechanical seal and the second mechanical seal work simultaneously, and the auxiliary impeller is started to accelerate heat dissipation. The mechanism can automatically switch the sealing mode according to the rotating speed change, effectively reduce the energy loss and improve the safety and reliability of the unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid machinery, in particular to a mechanical seal mechanism of a submersible pump switching with rotating speed. BACKGROUND

[0002] In the operation process of a variable frequency submersible pump, the rotating speed of the motor is variable, which enables the pump head part of the unit to output a continuously adjustable lift. However, this variable rotating speed characteristic also brings challenges to the mechanical seal. When the unit is in low-speed operation, the generated axial force is relatively small; while in high-speed operation, the axial force will significantly increase.

[0003] If only a single mechanical seal is used in the unit, in the high-speed and large-lift working condition, the single mechanical seal may not be able to effectively realize the sealing function of the motor cavity. This will cause the conveying medium to possibly mix into the motor cavity, thereby directly affecting the service life of the unit. On the contrary, if a double mechanical seal is used, in the low-speed and small-lift condition, the double mechanical seal works simultaneously, which not only causes energy waste, but also accelerates the damage of the mechanical seal due to the heat accumulation between the two mechanical seals, thereby also affecting the service life of the unit.

[0004] In view of the above problems that the mechanical seal is difficult to be used in high and low rotating speeds, the present application provides a mechanical seal mechanism of a submersible pump switching with rotating speed, aiming at solving the problems existing in the prior art. SUMMARY

[0005] The present application aims to provide a mechanical seal mechanism of a submersible pump switching with rotating speed, to effectively solve the problems existing in the prior art. The technical scheme can use only a single mechanical seal when the unit is in low-speed operation, thereby reducing energy consumption and realizing the effect of energy saving and environmental protection; while in high-speed operation, the double mechanical seal will work simultaneously, and the mechanical seal cavity will start forced convection heat exchange, accelerating the cooling process of the double mechanical seal, thereby significantly improving the safety and reliability of the unit.

[0006] To achieve the above object, the application provides the following scheme: a mechanical seal mechanism of a submersible pump switching with rotating speed, comprising: a main shaft; a first mechanical seal comprising a first static ring and a first dynamic ring; a second mechanical seal comprising a second static ring and a second dynamic ring; a hydraulic drive assembly comprising a hydraulic cylinder body, a piston, a piston rod and a hydraulic cylinder spring, the piston separating the hydraulic cylinder body into a hydraulic cylinder left cavity and a hydraulic cylinder right cavity, the piston rod being connected to the piston at one end and connected to the second static ring at the other end; an auxiliary impeller assembly comprising an auxiliary impeller and an auxiliary impeller base, an auxiliary impeller gap being arranged between the auxiliary impeller and the auxiliary impeller base; a fluid passage for guiding fluid to drive the hydraulic drive assembly according to the change of rotating speed; wherein, when the submersible pump is at a low or medium rotating speed, only the first mechanical seal works, when the submersible pump is at a high rotating speed, the first mechanical seal and the second mechanical seal work simultaneously, and the auxiliary impeller is started to accelerate heat dissipation.

[0007] Further, the contact end faces of the auxiliary impeller and the auxiliary impeller base are ball end faces, and the auxiliary impeller gap is provided with an auxiliary impeller spring and an auxiliary impeller seal ring.

[0008] Further, the ring width of the auxiliary impeller seal ring is consistent with the ring width of the auxiliary impeller gap.

[0009] Further, the fluid passage comprises guide vane through holes one, two and three arranged on the guide vane, the guide vane through hole one being connected to a guide vane internal flow area and an auxiliary impeller outlet area, the guide vane through hole two being connected to an impeller flow area and an auxiliary impeller inlet area, and the guide vane through hole three being connected to the guide vane through hole two and a hydraulic cylinder through hole.

[0010] Further, one end of the hydraulic cylinder through hole is connected to the guide vane through hole three, and the other end is connected to the hydraulic cylinder left cavity.

[0011] Further, a one-way valve is arranged at the guide vane through hole two for controlling one-way flow of fluid.

[0012] Further, an auxiliary impeller cavity and an auxiliary impeller through hole are arranged in the auxiliary impeller, one end of the auxiliary impeller through hole being connected to the auxiliary impeller cavity, and the other end being connected to the auxiliary impeller gap.

[0013] Further, an auxiliary impeller base cavity and an auxiliary impeller base through hole are arranged in the auxiliary impeller base, one end of the auxiliary impeller base through hole being connected to the auxiliary impeller base cavity, and the other end being connected to the auxiliary impeller gap.

[0014] Further, the left end of the piston rod is in contact with the right end of the auxiliary impeller seal ring.

[0015] Further, the hydraulic cylinder spring is arranged in the hydraulic cylinder right cavity for providing an elastic force opposite to the liquid pressure in the hydraulic cylinder left cavity.

[0016] From the above technical solutions, the application provides a mechanical seal mechanism of a submersible pump which switches with rotating speed, realizes automatic switching of the mechanical seal under different rotating speeds through reasonable structural design, effectively solves the problems in the prior art, improves the adaptability of the submersible pump under different working conditions, reduces the maintenance cost, and improves the operation efficiency and economy of the whole submersible pump system. BRIEF DESCRIPTION OF DRAWINGS

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

[0018] Figure 1 Fig. 1 is a structural schematic diagram of the mechanical seal mechanism of the submersible pump in a single mechanical seal state;

[0019] Figure 2 Fig. 2 is a structural schematic diagram of the mechanical seal mechanism of the submersible pump in a double mechanical seal state; Figure 1 Fig. 3 is an enlarged view of part A in Fig. 2;

[0020] Figure 3 Fig. 4 is an enlarged view of part B in Fig. 2; Figure 2 Fig. 5 is a structural schematic diagram of the mechanical seal mechanism of the submersible pump in a single mechanical seal state;

[0021] Figure 4 Fig. 6 is a structural schematic diagram of the mechanical seal mechanism of the submersible pump in a double mechanical seal state;

[0022] Figure 5 Fig. 7 is a position state diagram of the auxiliary impeller spring and the auxiliary impeller seal ring in a transmission liquid filling state (a), a single mechanical seal working state (b) and a double mechanical seal working state (c) respectively.

[0023] In the drawings: 1, main shaft; 2, impeller; 3, end cover; 4, guide vane; 401, guide vane through hole one; 402, guide vane through hole two; 403, guide vane through hole three; 5, middle section of pump body; 6, front section of motor; 7, middle section of motor; 8, sliding bearing; 9, first static ring; 10, first dynamic ring; 11, second static ring; 12, second dynamic ring; 13, auxiliary impeller; 1301, auxiliary impeller cavity; 1302, auxiliary impeller through hole; 14, auxiliary impeller base; 1401, auxiliary impeller base cavity; 1402, auxiliary impeller base through hole; 1314, auxiliary impeller gap; 15, hydraulic cylinder body; 1501, left cavity of hydraulic cylinder; 1502, right cavity of hydraulic cylinder; 1503, through hole of hydraulic cylinder; 16, piston; 17, piston rod; 18, hydraulic cylinder spring; 19, one-way valve; 20, auxiliary impeller spring; 21, auxiliary impeller seal ring. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0025] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0026] Referring to Figures 1 to 5 The embodiment provides a mechanical seal mechanism of a submersible pump switched with rotating speed, which comprises a pump body structure, a first mechanical seal, a second mechanical seal, a hydraulic drive assembly, an auxiliary impeller 13 assembly and a fluid passage.

[0027] The pump body structure is the basic framework of the entire submersible pump, mainly comprising a main shaft 1, an impeller 2, an end cover 3, a guide vane 4, a pump body middle section 5, a motor front section 6 and a motor middle section 7. Among them, the impeller 2, the end cover 3, the guide vane 4, the pump body middle section 5, the motor front section 6 and the motor middle section 7 jointly constitute a medium conveying flow channel, and the main shaft 1, the guide vane 4 and the motor front section 6 form a mechanical seal cavity. The main shaft 1 penetrates through the entire pump body and is the core component for connecting and driving various parts. The impeller 2 is assembled on the main shaft 1 and is responsible for converting power into kinetic energy of fluid to push the fluid to flow in the pump. The end cover 3 plays a role in closing and protecting the internal structure of the pump body, ensuring that the fluid inside the pump body does not leak. The components work together to achieve efficient sealing function.

[0028] In the above embodiment, the guide vane 4 is an important part of the flow channel in the pump, and a plurality of through holes are arranged on the guide vane 4, including guide vane through hole one 401, guide vane through hole two 402 and guide vane through hole three 403. These through holes constitute the fluid passage and play a key role in fluid conveying and pressure regulation. The pump body middle section 5 is a key structure connecting the impeller 2 and other components, which not only supports the impeller 2 but also works with other components to ensure stable operation of the pump body. The motor front section 6 and the motor middle section 7 constitute the main part of the motor. The motor front section 6 is assembled with a sliding bearing 8 for supporting the main shaft 1 and reducing friction, and the motor middle section 7 is fixedly connected with the motor front section 6 to jointly constitute the main structure of the motor.

[0029] The above embodiment is in terms of sealing mechanism, the first static ring 9 and the first dynamic ring 10 are assembled between the motor front section 6 and the main shaft 1 to form the first sealing, which ensures effective sealing of the motor cavity at low and medium speed. The second static ring 11 and the second dynamic ring 12 work together with the first sealing at high speed to further enhance the sealing effect. The auxiliary impeller 13 and the auxiliary impeller base 14 are connected through a special assembly structure to form an auxiliary impeller 13 assembly. The auxiliary impeller gap 1314 is left between the auxiliary impeller 13 and the auxiliary impeller base 14. The auxiliary impeller spring 20 and the auxiliary impeller seal ring 21 are used to control the transmission liquid in the auxiliary impeller gap 1314 to ensure effective sealing and cooling at different speeds.

[0030] In the above embodiment, the hydraulic cylinder body 15, the piston 16, the piston rod 17 and the hydraulic cylinder spring 18 form a hydraulic drive assembly. According to the change of the speed and pressure of the pump, the position of the piston 16 is automatically adjusted to control the rotation state of the auxiliary impeller 13. The one-way valve 19 is installed at a specific position of the guide vane 4 to ensure the one-way flow of the fluid and avoid backflow. The whole mechanical sealing mechanism works together to use single mechanical sealing at low and medium speed to reduce energy loss, and switches to double mechanical sealing at high speed and starts forced convection heat transfer to accelerate cooling and improve the safety and reliability of the unit. This design not only improves the operating efficiency of the pump, but also prolongs the service life of the mechanical seal and enhances the stability and reliability of the whole submersible pump system.

[0031] In one specific embodiment, the auxiliary impeller 13 and the auxiliary impeller base 14 are assembled and connected, relying on the internal positioning structure, not fixed, and the contact end face of the auxiliary impeller 13 and the auxiliary impeller base 14 is a ball end face. There is an assembly circular groove, i.e. the auxiliary impeller gap 1314, between the auxiliary impeller 13 and the auxiliary impeller base 14. One end of the auxiliary impeller spring 20 is fixedly connected to the auxiliary impeller gap 1314, and the other end is fixedly connected to the auxiliary impeller seal ring 21. The ring width of the auxiliary impeller seal ring 21 is consistent with the ring width of the auxiliary impeller gap 1314, which can seal the transmission liquid in the auxiliary impeller gap 1314. The contact part of the auxiliary impeller seal ring 21 with the auxiliary impeller 13 and the auxiliary impeller base 14 is made of wear-resistant material. The left part of the auxiliary impeller seal ring 21 is provided with an auxiliary impeller seal ring 21 through hole.

[0032] In one embodiment, the hydraulic cylinder body 15, the piston 16, and the piston rod 17 are assembled in combination, wherein the piston 16 separates the hydraulic cylinder body 15 into a hydraulic cylinder left cavity 1501 and a hydraulic cylinder right cavity 1502, and the hydraulic cylinder spring 18 is located in the hydraulic cylinder right cavity 1502. One end of the hydraulic cylinder spring 18 is connected to the piston 16, and the other end is connected to the inner wall of the hydraulic cylinder right cavity 1502. The guide vane 4 is provided with a guide vane through hole one 401 and a guide vane through hole two 402, and the one-way valve 19 is assembled to the guide vane through hole two 402, which flows in one direction from right to left. The guide vane 4 is assembled to the main shaft 1 and positioned with the motor front section 6, and the guide vane 4, the motor front section 6, and the motor middle section 7 are fixedly connected. At this time, the piston rod 17 enters the auxiliary impeller gap 1314, and the left end of the piston rod 17 is in contact with the right end of the auxiliary impeller sealing ring 21.

[0033] In one embodiment, the second static ring 11 is fixedly connected to the right end of the piston rod 17. The second dynamic ring 12 is assembled to the main shaft 1 and in contact with the main shaft 1. The impeller 2 is assembled to the main shaft 1 and not in contact with the main shaft 1, and the impeller 2 and the end cover 3 are fixedly connected. The guide vane 4 is provided with a guide vane through hole one 401, a guide vane through hole two 402, and a guide vane through hole three 403. One end of the guide vane through hole one 401 is connected to the internal flow area of the guide vane 4, and the other end is connected to the outlet area of the auxiliary impeller 13. One end of the guide vane through hole two 402 is connected to the flow area of the impeller 2, and the other end is connected to the inlet area of the auxiliary impeller 13. One end of the guide vane through hole three 403 is connected to the guide vane through hole two 402, and the other end is connected to the hydraulic cylinder through hole 1503. The hydraulic cylinder body 15 is provided with the hydraulic cylinder through hole 1503, and one end of the hydraulic cylinder through hole 1503 is connected to the guide vane through hole three 403, and the other end is connected to the hydraulic cylinder left cavity 1501.

[0034] In one embodiment, the auxiliary impeller 13 is provided with an auxiliary impeller cavity 1301 and an auxiliary impeller through hole 1302. One end of the auxiliary impeller through hole 1302 is connected to the auxiliary impeller cavity 1301, and the other end is connected to the auxiliary impeller gap 1314. The auxiliary impeller base 14 is provided with an auxiliary impeller base cavity 1401 and an auxiliary impeller base through hole 1402. One end of the auxiliary impeller base through hole 1402 is connected to the auxiliary impeller base cavity 1401, and the other end is connected to the auxiliary impeller gap 1314. After the auxiliary impeller 13 and the auxiliary impeller base 14 are assembled, the auxiliary impeller cavity 1301 and the auxiliary impeller base cavity 1401 are filled with transmission liquid. During the liquid filling process, the auxiliary impeller spring 20 is pressed to the leftmost side of the auxiliary impeller gap 1314, and after the liquid is filled, the auxiliary impeller spring 20 rebounds, and the auxiliary impeller sealing ring 21 seals the liquid in the auxiliary impeller cavity 1301 and the auxiliary impeller base cavity 1401.

[0035] The working principle of the embodiment of the application is as follows:

[0036] When the main pump of the submersible pump is in low or medium speed, the first mechanical seal (the first dynamic ring 10 and the first static ring 9) plays a sealing role, and the second mechanical seal (the second dynamic ring 12 and the second static ring 11) does not play a sealing role. When the pump is in high speed, the second mechanical seal works simultaneously with the first mechanical seal. When the main pump is in low or medium speed, the conveying medium flows into the left cavity 1501 of the hydraulic cylinder through the flow channel of the impeller 2, the gap of the guide vane 4 of the impeller 2, the second guide vane through hole 402, the third guide vane through hole 403 and the hydraulic cylinder through hole 1503. The liquid pressure in the left cavity 1501 of the hydraulic cylinder is insufficient to overcome the spring force of the right cavity 1502 of the hydraulic cylinder to push the piston 16 and the piston rod 17, at this time, the piston rod 17 is located at the leftmost horizontal position, the closed part in the auxiliary impeller sealing ring 21 is located in the middle area of the auxiliary impeller through hole 1302 and the auxiliary impeller base through hole 1402, the auxiliary impeller through hole 1302 and the auxiliary impeller base through hole 1402 are separated, that is, the auxiliary impeller cavity 1301 and the auxiliary impeller base cavity 1401 are disconnected, at this time, the main shaft 1 rotates to drive the auxiliary impeller base 14 to rotate, but cannot drive the auxiliary impeller 13 to rotate. The piston rod 17 and the second static ring 11 are tightly connected, the second static ring 11 is located at the leftmost horizontal position, the second static ring 11 and the second dynamic ring 12 do not contact, and the second mechanical seal does not work, at this time, only the first mechanical seal works.

[0037] When the main pump of the submersible pump is in low or medium speed, the first mechanical seal (the first dynamic ring 10 and the first static ring 9) plays a sealing role, and the second mechanical seal (the second dynamic ring 12 and the second static ring 11) does not play a sealing role. When the pump is in high speed, the second mechanical seal works simultaneously with the first mechanical seal. When the main pump is in low or medium speed, the conveying medium flows into the left cavity 1501 of the hydraulic cylinder through the flow channel of the impeller 2, the gap of the guide vane 4 of the impeller 2, the second guide vane through hole 402, the third guide vane through hole 403 and the hydraulic cylinder through hole 1503. The liquid pressure in the left cavity 1501 of the hydraulic cylinder is insufficient to overcome the spring force of the right cavity 1502 of the hydraulic cylinder to push the piston 16 and the piston rod 17, at this time, the piston rod 17 is located at the leftmost horizontal position, the closed part in the auxiliary impeller sealing ring 21 is located in the middle area of the auxiliary impeller through hole 1302 and the auxiliary impeller base through hole 1402, the auxiliary impeller through hole 1302 and the auxiliary impeller base through hole 1402 are separated, that is, the auxiliary impeller cavity 1301 and the auxiliary impeller base cavity 1401 are disconnected, at this time, the main shaft 1 rotates to drive the auxiliary impeller base 14 to rotate, but cannot drive the auxiliary impeller 13 to rotate. The piston rod 17 and the second static ring 11 are tightly connected, the second static ring 11 is located at the leftmost horizontal position, the second static ring 11 and the second dynamic ring 12 do not contact, and the second mechanical seal does not work, at this time, only the first mechanical seal works.

[0038] Compared with the prior art, the embodiment of the application at least discloses the following beneficial effects:

[0039] The embodiment realizes the automatic switching of the mechanical seal mechanism of the submersible pump at different rotating speeds through a unique structural design, thereby significantly improving the performance and service life of the unit. When running at medium and low rotating speeds, only the first mechanical seal works, which reduces unnecessary energy loss and achieves the effect of energy saving and environmental protection. At the same time, since the problem of heat accumulation caused by the simultaneous operation of double mechanical seals at medium and low rotating speeds is avoided, the damage speed of the mechanical seal is effectively slowed down, thereby prolonging the service life of the mechanical seal. When the submersible pump enters a high rotating speed running state, the hydraulic drive assembly automatically drives the second mechanical seal to start working according to the change of fluid pressure guided by the fluid passage, realizing the simultaneous sealing of double mechanical seals, enhancing the sealing effect, ensuring that the motor cavity will not mix with the conveying medium, thereby improving the safety and reliability of the unit. In addition, the start of the auxiliary impeller 13 further accelerates the heat dissipation in the mechanical seal cavity area, effectively solving the problem of heat accumulation at high rotating speed, and further improving the stability and reliability of the unit under high load operation. This automatic switching mechanism based on structure not only improves the adaptability of the submersible pump under different working conditions, but also reduces the maintenance cost, and improves the operation efficiency and economy of the entire submersible pump system.

[0040] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0041] The above-described embodiments are only descriptions of the preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A submersible pump mechanical seal mechanism that switches with rotational speed, characterized in that, include: Main spindle (1); The first mechanical seal includes a first stationary ring (9) and a first rotating ring (10); The second mechanical seal includes a second stationary ring (11) and a second rotating ring (12). The hydraulic drive assembly includes a hydraulic cylinder body (15), a piston (16), a piston rod (17), and a hydraulic cylinder spring (18). The piston (16) divides the hydraulic cylinder body (15) into a hydraulic cylinder left chamber (1501) and a hydraulic cylinder right chamber (1502). One end of the piston rod (17) is connected to the piston (16), and the other end is connected to a second stationary ring (11). The auxiliary impeller (13) assembly includes an auxiliary impeller (13) and an auxiliary impeller base (14), with an auxiliary impeller gap (1314) between them. A fluid passage for guiding fluid to drive the hydraulic drive assembly according to changes in rotational speed; When the submersible pump is at low to medium speed, only the first mechanical seal works. When the pump is at high speed, the first and second mechanical seals work simultaneously, and the auxiliary impeller (13) is activated to accelerate heat dissipation.

2. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 1, characterized in that, The contact end face of the auxiliary impeller (13) and the auxiliary impeller base (14) is a ball end face, and the auxiliary impeller gap (1314) is provided with an auxiliary impeller spring (20) and an auxiliary impeller sealing ring (21).

3. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 2, characterized in that, The ring width of the auxiliary impeller sealing ring (21) is consistent with the ring width of the auxiliary impeller clearance (1314).

4. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 1, characterized in that, The fluid passage includes a guide vane through hole one (401), a guide vane through hole two (402), and a guide vane through hole three (403) provided on the guide vane (4). The guide vane through hole one (401) connects the internal flow area of ​​the guide vane (4) and the outlet area of ​​the auxiliary impeller (13). The guide vane through hole two (402) connects the flow area of ​​the impeller (2) and the inlet area of ​​the auxiliary impeller (13). The guide vane through hole three (403) connects the guide vane through hole two (402) and the hydraulic cylinder through hole (1503).

5. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 4, characterized in that, One end of the hydraulic cylinder through hole (1503) is connected to the guide vane through hole three (403), and the other end is connected to the left cavity (1501) of the hydraulic cylinder.

6. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 4, characterized in that, A one-way valve (19) is provided at the guide vane through hole two (402) to control the unidirectional flow of fluid.

7. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 1, characterized in that, The auxiliary impeller (13) is provided with an auxiliary impeller cavity (1301) and an auxiliary impeller through hole (1302). One end of the auxiliary impeller through hole (1302) is connected to the auxiliary impeller cavity (1301), and the other end is connected to the auxiliary impeller gap (1314).

8. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 1 or 7, characterized in that, The auxiliary impeller base (14) is provided with an auxiliary impeller base cavity (1401) and an auxiliary impeller base through hole (1402). One end of the auxiliary impeller base through hole (1402) is connected to the auxiliary impeller base cavity (1401), and the other end is connected to the auxiliary impeller gap (1314).

9. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 1, characterized in that, The left end of the piston rod (17) is in contact with the right end of the auxiliary impeller sealing ring (21).

10. The submersible pump mechanical seal mechanism that switches with rotational speed according to claim 1, characterized in that, The hydraulic cylinder spring (18) is located in the right chamber (1502) of the hydraulic cylinder and is used to provide an elastic force opposite to the liquid pressure in the left chamber (1501) of the hydraulic cylinder.

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