Totally-closed long-shaft submerged pump

Abstract

The invention relates to the technical field of long-shaft submerged pumps, in particular to a totally-closed long-shaft submerged pump which comprises a supporting sleeve, a bearing seat and a pump body which are sequentially arranged from top to bottom, the pump body is provided with a centrifugal cavity, a suction end and a discharge end, an impeller is arranged in the centrifugal cavity, a shaft sleeve is arranged on the impeller, and the shaft sleeve penetrates through the bearing seat and extends into the supporting sleeve. A pump shaft is arranged in the supporting sleeve; one end of the pump shaft is connected with the shaft sleeve; a bearing is arranged in the bearing seat, a sealing piece is arranged at the bottom of the bearing seat, a gap is formed between the sealing piece and the impeller, an abutting plate is arranged in the gap, and a flexible piece is arranged below the abutting plate. The sealing element is always subjected to upward pressing force in the operation process of the pump, tiny gaps generated by long-term use, vibration or temperature change of the sealing element can be compensated in real time, and the sealing effectiveness of a totally-enclosed structure is ensured.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of long-shaft submersible pumps, and particularly relates to a fully-closed long-shaft submersible pump. BACKGROUND

[0002] In industrial scenes such as oil drilling, chemical wastewater treatment and mine tailings transportation, the fully-closed long-shaft submersible pump becomes a key conveying device because it can realize deep submersible pumping of the medium and avoid leakage of the medium to pollute the environment. The core requirement of such a pump is "full-closed sealing reliability" and "long-shaft running stability". On the one hand, the conveyed medium often contains corrosive components such as salt additives in drilling mud or solid particles, which are easy to cause wear of the sealing structure. On the other hand, the length of the pump shaft is usually 3-5 m, and radial runout and vibration are easy to occur during high-speed operation, which further aggravates the loosening risk of the sealing element. If the sealing fails, not only will the leakage of the medium cause safety accidents, but also the leaked medium may invade the bearing seat, causing bearing rust and lubrication failure, and finally causing pump body shutdown failure.

[0003] Chinese authorized patent publication No. CN222702166U discloses a novel fully-closed long-shaft submersible pump, and relates to the technical field of drilling equipment. A mounting plate is connected with a sheath through a flange and bolts, the lower part of the sheath is connected with a snail shell, one side of the snail shell is connected with a liquid outlet pipe, an impeller is installed in the snail shell, the impeller is connected with a pump shaft, a sleeve shaft is welded on the upper part of the pump shaft, a sink hole of the sleeve shaft is connected with a fixed shaft through a bearing set, a support is welded on the upper part of the mounting plate, the fixed shaft is fixedly connected with the support, a belt pulley A is welded on the upper part of the sleeve shaft, the belt pulley A is connected with a belt pulley B through a triangular belt, the belt pulley B is connected with an output shaft of a motor through a flat key, and the motor is installed on the support. The novel fully-closed long-shaft submersible pump has the beneficial effects that the sleeve shaft is welded on the upper part of the pump shaft, the sleeve shaft is connected with the fixed shaft through the bearing set, the cantilever part of the pump shaft can be shortened, the vibration of the pump shaft is reduced, the motor drives the sleeve shaft through the belt transmission, the motor can play an overload protection role, and the bearings connected with the sleeve shaft and the fixed shaft are all in the sleeve shaft, so that the damage of the bearings caused by splashing of the mud is avoided.

[0004] However, the above-mentioned comparative document and the existing similar technology still have the following defects: The lip-shaped sealing ring in the comparative document only relies on the pre-tightening force during installation to realize sealing. When the pump shaft is in high-speed operation and vibration occurs, the fitting gap between the sealing cover and the sleeve shaft is easy to increase, a small gap is formed between the lip-shaped sealing ring and the inner wall of the sleeve shaft, and the sealing element always bears a fixed pressure during the start-stop process of the pump body. Elastic fatigue is easy to occur due to long-term pressure, or local wear is caused due to vibration, the replacement cycle of the sealing element is shortened, and the equipment maintenance cost is increased. SUMMARY

[0005] To address the aforementioned issues, a fully enclosed long-shaft submersible pump is provided. This pump utilizes a dynamic sealing mechanism where the impeller deforms under water pressure during operation, driving a flexible component to push a pressure plate upwards against the seal. This ensures the seal is constantly subjected to upward pressure during pump operation. Compared to traditional sealing structures that rely solely on pre-tightening force, this mechanism can compensate for minute gaps in the seal caused by long-term use, vibration, or temperature changes, ensuring the sealing effectiveness of the fully enclosed structure.

[0006] To address the problems of existing technologies, this invention provides a fully enclosed long-shaft submersible pump, comprising a support sleeve, a bearing housing, and a pump body arranged sequentially from top to bottom. The pump body has a centrifugal chamber, a suction end, and a discharge end. An impeller is provided in the centrifugal chamber, and a bushing is provided on the impeller. The bushing passes through the bearing housing and extends into the support sleeve. A pump shaft is provided inside the support sleeve, and one end of the pump shaft is connected to the bushing. The bearing housing contains a bearing for connecting the bushing. A seal is located at the bottom of the bearing housing, forming a gap between the seal and the impeller. A pressure plate is located within the gap, and a flexible member is located below the pressure plate. The flexible member has an initial state and a working state. In the initial state, the top of the flexible member does not contact the bottom of the pressure plate. In the working state, the top of the flexible member contacts the bottom of the pressure plate and pushes the pressure plate towards the seal until the top of the pressure plate is in contact with the bottom of the seal, thus subjecting the seal to an upward force.

[0007] Preferably, the sealing element is a combined sealing ring, which includes a polytetrafluoroethylene wear-resistant layer and a nitrile rubber elastic layer arranged sequentially from top to bottom. An annular sealing groove is provided at the bottom of the bearing seat, and the combined sealing ring is embedded in the annular sealing groove. The top of the combined sealing ring is in close contact with the bottom of the annular sealing groove.

[0008] Preferably, the pressure plate is a circular metal plate with a diameter consistent with the outer diameter of the bottom of the seal. The edge of the pressure plate is provided with a guide boss, and the inner wall of the pump body is provided with a guide groove that matches the guide boss. The pressure plate moves axially through the sliding fit between the guide boss and the guide groove.

[0009] Preferably, the top of the pressure plate is provided with a circular mounting groove, and a circular rubber ring that can fit against the bottom of the seal is provided in the circular mounting groove.

[0010] Preferably, the flexible component is an annular rubber with a cavity, and an annular frame is provided above the impeller in the pump body. The inner and outer rings of the flexible component are respectively disposed on the annular frame, and the material of the annular rubber is fluororubber.

[0011] Preferably, the cavity of the flexible component contains a medium.

[0012] Preferably, the pump shaft is provided with an external spline at one end near the bushing, and the inner wall of the bushing is provided with an internal spline that matches the external spline. The pump shaft and the bushing are connected by a spline engagement, and the mating surfaces of the pump shaft and the bushing are coated with a wear-resistant lubricating coating.

[0013] Preferably, the upper part of the bearing housing is constructed with an annular liquid collection cavity, the upper end of the bushing passes through the annular liquid collection cavity and extends into the interior of the support sleeve, and a detector and a water pumping pipe are installed through the top of the bearing housing, with the working end of the detector and the working end of the water pumping pipe extending to the deepest position of the annular liquid collection cavity respectively.

[0014] Preferably, the lower section of the annular liquid collecting cavity has a funnel-shaped cross-section.

[0015] Preferably, the detector is a liquid level sensor, and the detection end of the liquid level sensor is flush with the deepest position of the annular liquid collection cavity.

[0016] The advantages of this invention compared to the prior art are: 1. This invention utilizes a dynamic sealing mechanism where the impeller deforms due to water pressure during operation, driving the flexible component to push the pressure plate upward against the seal. This ensures that the seal is always subjected to upward pressure during pump operation. Compared to traditional sealing structures that rely solely on installation pre-tightening force, this invention can compensate for minute gaps in the seal caused by long-term use, vibration, or temperature changes in real time, ensuring the sealing effectiveness of the fully enclosed structure.

[0017] 2. The combined sealing ring of the present invention adopts a double-layer structure of polytetrafluoroethylene wear-resistant layer and nitrile rubber elastic layer. The polytetrafluoroethylene wear-resistant layer can resist the frictional loss caused by repeated extrusion of the pressure plate, and the nitrile rubber elastic layer can fill the sealing gap through deformation, thereby improving the service life of the sealing component and the stability of the sealing effect.

[0018] 3. The annular liquid collection chamber of the present invention can effectively intercept leaked liquid that seeps along the shaft sleeve, the detector can monitor the leakage status in real time, and the pumping pipe can actively discharge the accumulated liquid, forming a closed-loop protection of collection, monitoring and treatment, which avoids the leaked liquid from entering the support sleeve and corroding precision components such as bearings and pump shaft, and improves the safety of pump operation. Attached Figure Description

[0019] Figure 1 This is a partial three-dimensional structural diagram of a fully enclosed long-shaft submersible pump according to the present invention.

[0020] Figure 2 This is a partial cross-sectional view of a fully enclosed long-shaft submersible pump according to this invention application.

[0021] Figure 3 yes Figure 2 Enlarged view of point A in the middle.

[0022] Figure 4 This is a partial three-dimensional structural cross-sectional view of the bearing housing and pump body of a fully enclosed long-shaft submersible pump according to this invention application.

[0023] Figure 5 This is a partial three-dimensional exploded view of the bearing housing and pump body of a fully enclosed long-shaft submersible pump according to this invention application.

[0024] Figure 6 This is a partial three-dimensional exploded view of the pump body of a fully enclosed long-shaft submersible pump according to the present invention.

[0025] Figure 7 yes Figure 6 Enlarged view of section B in the middle.

[0026] Figure 8 This is an exploded view of the pressure plate and circular rubber ring of a fully enclosed long-shaft submersible pump according to this invention application.

[0027] Figure 9 This is an exploded view of the annular frame and flexible components of a fully enclosed long-shaft submersible pump according to this invention application.

[0028] Figure 10 This is an exploded view of the pump shaft and bushing of a fully enclosed long-shaft submersible pump according to this invention application.

[0029] The numbers on the map are: Detailed Implementation

[0030] To further understand the features, technical means, and specific objectives and functions achieved by this invention application, the invention application will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0031] Reference Figures 1 to 4 As shown: A fully enclosed long-shaft submersible pump includes a support sleeve 1, a bearing seat 2, and a pump body 3 arranged sequentially from top to bottom. The pump body 3 has a centrifugal chamber 31, a suction end 32, and a discharge end 33. An impeller 34 is provided in the centrifugal chamber 31, and a bushing 341 is provided on the impeller 34. The bushing 341 passes through the bearing seat 2 and extends into the support sleeve 1. A pump shaft 4 is provided in the support sleeve 1, and one end of the pump shaft 4 is connected to the bushing 341. The bearing housing 2 is provided with a bearing 21 for connecting the bushing 341. The bottom of the bearing housing 2 is provided with a seal 22, and a gap is formed between the seal 22 and the impeller 34. A pressure plate 23 is provided in the gap, and a flexible member 24 is provided below the pressure plate 23. The flexible member 24 has an initial state and a working state. In the initial state, the top of the flexible member 24 does not contact the bottom of the pressure plate 23. In the working state, the top of the flexible member 24 contacts the bottom of the pressure plate 23 and pushes the pressure plate 23 toward the seal 22 until the top of the pressure plate 23 is in contact with the bottom of the seal 22, so that the seal 22 is subjected to an upward force.

[0032] When the long-shaft submersible pump starts running, the impeller 34 rotates at high speed in the centrifugal chamber 31, and the liquid is transported from the suction end 32 to the discharge end 33 by the action of centrifugal force. At this time, the liquid will deform the flexible part 24 by water pressure. In the initial state of the flexible component 24, when the long shaft submersible pump is not started, the flexible component 24 is in a naturally relaxed state, and its top is kept at a gap with the bottom of the pressure plate 23. The pressure plate 23 does not exert pressure on the seal 22 at the bottom of the bearing seat 2, and the seal 22 only relies on its own installation pre-tightening force to achieve basic sealing. In operation, as liquid enters the centrifugal chamber 31 and generates water pressure through the high-speed rotation of the impeller 34, the flexible component 24 undergoes elastic deformation under the water pressure. Its top gradually contacts and pushes the pressure plate 23. Under the thrust of the flexible component 24, the pressure plate 23 moves axially toward the seal 22 until the top of the pressure plate 23 is tightly fitted with the bottom of the seal 22, and continues to apply an upward force to the seal 22. At this time, the seal 22 is tightly fitted to the bottom of the bearing seat 2 under the push of the pressure plate 23, effectively preventing the fluid inside the pump body 3 from leaking out along the bearing 21. When the long-shaft submersible pump stops operating, the flexible component 24 returns to its initial state, the pressure plate 23 falls back, and the force on the seal 22 is released, realizing automatic pressure relief and reset, ensuring the sealing reliability and operational stability during the start-up and shutdown process of the equipment.

[0033] Reference Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown: The sealing element 22 is a combined sealing ring 221. The combined sealing ring 221 includes a polytetrafluoroethylene wear-resistant layer 2211 and a nitrile rubber elastic layer 2212 arranged sequentially from top to bottom. An annular sealing groove is provided at the bottom of the bearing seat 2. The combined sealing ring 221 is embedded in the annular sealing groove, and the top of the combined sealing ring 221 is in close contact with the bottom of the annular sealing groove.

[0034] After the combined sealing ring 221 is embedded in the groove, its top fits tightly against the bottom of the sealing groove, forming an initial fixed constraint to prevent the combined sealing ring 221 from shifting as a whole due to vibration during the operation of the long-shaft submersible pump. The polytetrafluoroethylene wear-resistant layer 2211 has wear resistance and corrosion resistance. When the pump is running, the pressure plate 23 is pushed upward by the flexible part 24 to squeeze the combined sealing ring 221. The wear-resistant layer can effectively resist the friction loss caused by repeated contact of the pressure plate 23, and at the same time withstand the scouring of particles in the liquid (such as mud) in the pump body 3, and avoid the sealing gap of the combined sealing ring 221 due to wear. The nitrile rubber elastic layer 2212 has elastic deformation capability. In the initial state, the rubber layer forms a preliminary seal with the sealing groove and the pressure plate 23 (when not in contact) by its own elasticity. When the long shaft submersible pump is running, the pressure plate 23 applies upward pressure, and the nitrile rubber elastic layer 2212 is squeezed and undergoes elastic deformation. Its deformation can fill the small gap between the combined sealing ring 221 and the sealing groove and the pressure plate 23, so that the sealing surface fits more tightly and the sealing pressure is increased. Even if slight wear occurs after long-term operation, the elasticity of the nitrile rubber elastic layer 2212 can still compensate for the wear through deformation and maintain a stable sealing effect.

[0035] Reference Figure 3 , Figure 6 and Figure 7 As shown: The pressure plate 23 is a circular metal plate with a diameter that is the same as the outer diameter of the bottom of the seal 22. The edge of the pressure plate 23 is provided with a guide boss 231. The inner wall of the pump body 3 is provided with a guide groove 35 that is adapted to the guide boss 231. The pressure plate 23 moves axially through the sliding fit between the guide boss 231 and the guide groove 35.

[0036] When the pressure plate 23 moves upward under the push of the flexible member 24, its top can form a complete surface contact with the bottom of the seal 22, thereby evenly distributing the thrust of the flexible member 24 to the entire bottom of the seal 22, ensuring the sealing performance of the seal 22 and the bearing seat 2. By cooperating with the guide boss 231 and the guide groove 35, the movement direction of the pressure plate 23 is restricted, so that it can only move up and down along the axial direction (perpendicular to the contact surface of the seal 22), ensuring that the pressure plate 23 always moves in an attitude parallel to the bottom of the seal 22.

[0037] Reference Figure 8 As shown: The top of the pressure plate 23 is provided with a circular mounting groove 232, and a circular rubber ring 233 that can fit with the bottom of the seal 22 is provided in the circular mounting groove 232.

[0038] When the pressure plate 23 moves upward under the push of the flexible member 24, the circular rubber ring 233 first contacts the bottom of the seal 22. As the pressure plate 23 continues to move upward, the circular rubber ring 233 is squeezed and produces elastic deformation, which can automatically fill the tiny gap between the bottom of the seal 22 and the top of the pressure plate 23. When the long-shaft submersible pump is running, the thrust of the flexible part 24 may change instantaneously due to water pressure fluctuations. The elasticity of the circular rubber ring 233 can absorb such pressure fluctuations, preventing the metal pressure plate 23 from directly impacting the seal 22 and reducing wear or deformation of the seal 22 caused by excessive instantaneous force.

[0039] Reference Figures 2 to 4 As shown: The flexible component 24 is an annular rubber with a cavity. An annular frame 36 is provided inside the pump body 3 above the impeller 34. The inner and outer rings of the flexible component 24 are respectively provided on the annular frame 36. The material of the annular rubber is fluororubber.

[0040] When the long-shaft submersible pump is running, the water pressure generated by the rotation of the impeller 34 acts on the bottom of the annular rubber. The flexible component 24 with a cavity structure undergoes controllable elastic deformation under the pressure of the water. At this time, the cavity of the flexible component 24 is compressed, and the flexible component 24 bulges upward as a whole, thereby transmitting a stable and uniform thrust to the pressure plate 23. Fluororubber, as a material for ring-shaped rubber, has the characteristics of high and low temperature resistance, oil resistance, and chemical corrosion resistance. It solves the problem that ordinary rubber is prone to aging, hardening or swelling in the complex medium 241 environment inside the pump body 3, and ensures that the flexible part 24 maintains a stable elastic deformation capability during long-term use.

[0041] Reference Figure 2 and Figure 3 As shown: The cavity of the flexible component 24 contains a medium 241.

[0042] The flexible medium 241 filling the cavity of the flexible component 24 can be silicone oil, elastic gel, etc., as an intermediate carrier for pressure transmission, which can evenly distribute the water pressure generated by the rotation of the impeller 34 to the entire inner wall of the annular rubber cavity. When water pressure is applied to the bottom of the flexible component 24, the medium 241 will quickly transmit the local pressure to various areas of the cavity of the flexible component 24 through its own fluidity, so as to avoid excessive or insufficient deformation of the flexible component 24 due to uneven pressure distribution in the cavity of the flexible component 24, and ensure that the flexible component 24 bulges upward and outputs a uniform and continuous thrust to the pressure plate 23.

[0043] Reference Figure 10As shown: The pump shaft 4 is provided with an external spline 41 at one end near the bushing 341, and the inner wall of the bushing 341 is provided with an internal spline 3411 that is adapted to the external spline 41. The pump shaft 4 and the bushing 341 are connected by spline engagement, and the mating surfaces of the pump shaft 4 and the bushing 341 are coated with a wear-resistant lubricating coating.

[0044] The teeth of the external spline 41 are embedded in the tooth grooves of the internal spline 3411. Through the rigid contact of the tooth surfaces, the torque required for the rotation of the impeller 34 can be distributed to multiple tooth surfaces, avoiding tooth deformation or breakage caused by excessive force at a single contact point. At the same time, the circumferential constraint of the tooth meshing is stronger, which can strictly ensure the concentricity of the pump shaft 4 and the bushing 341, prevent vibration caused by eccentricity during high-speed rotation, and ensure stable operation of the impeller 34 in the centrifugal chamber 31. The wear-resistant lubricating coating applied to the mating surfaces of the pump shaft 4 and the bushing 341 can reduce the sliding friction resistance during spline tooth meshing. Furthermore, the wear-resistant lubricating coating itself has high hardness and wear resistance, which can prevent direct metal-to-metal contact between the pump shaft 4 and the bushing 341, resist wear and scraping of the tooth surface during long-term meshing transmission, and avoid increased transmission clearance due to tooth surface wear.

[0045] Reference Figures 2 to 4 As shown: The upper part of the bearing seat 2 is constructed with an annular liquid collection cavity 25. The upper end of the bushing 341 passes through the annular liquid collection cavity 25 and extends into the interior of the support sleeve 1. The top of the bearing seat 2 is equipped with a detector 26 and a water pumping pipe 27. The working end of the detector 26 and the working end of the water pumping pipe 27 extend to the deepest position of the annular liquid collection cavity 25, respectively.

[0046] The annular liquid collecting chamber 25 at the upper part of the bearing housing 2 is arranged around the bushing 341. When a small amount of leakage occurs in the operation of the pump body 3 (such as slight wear of the seal 22 due to long-term use, causing a small amount of liquid to seep upward along the outer wall of the bushing 341), the leaking liquid will flow along the outer wall of the bushing 341 under the action of gravity, and will eventually be intercepted and collected by the annular liquid collecting chamber 25. When the leakage reaches the response threshold of detector 26, a signal (such as an electrical signal or an optical signal) can be sent in real time. The fully enclosed long-shaft submersible pump is equipped with a controller, which can send the signal to the controller in a timely manner and alert the operator that there may be an abnormality in the sealing system. The working end of the pump pipe 27 also extends to the deepest part of the liquid collection chamber. It can actively extract the accumulated leaked liquid and guide it to the outside by means of external power (such as a small water pump that can be installed on the fully enclosed long-shaft submersible pump). This prevents the liquid from overflowing from the liquid collection chamber due to excessive accumulation and invading the support sleeve 1, which could damage the bearing 21, pump shaft 4 and other components, thereby further improving the sealing performance of the long-shaft submersible pump.

[0047] Reference Figure 2As shown: the lower section of the annular liquid collecting cavity 25 has a funnel-shaped cross-section.

[0048] When a small leak occurs in the pump body 3, such as slight wear of the seal 22 causing liquid to seep along the outer wall of the bushing 341, the leaked liquid flows downward along the bushing 341 into the annular liquid collecting chamber 25, and under the guidance of the funnel-shaped structure, it will automatically converge to the deepest position of the liquid collecting chamber.

[0049] Reference Figure 2 As shown: the detector 26 is a liquid level sensor, and the detection end of the liquid level sensor is flush with the deepest position of the annular liquid collection cavity 25.

[0050] Liquid level sensors can directly respond to the presence of liquid. Their detection principles (such as capacitive, float, and optical sensors) all use "whether or not there is contact with liquid" as the basis for judgment. They can accurately distinguish between "leaking liquid" and interference factors such as "humid water vapor" and "dust impurities", avoiding false alarms caused by the internal environment of the pump body 3 (such as mud vapor and small particles) and ensuring the reliability of the detection results.

[0051] The above embodiments only illustrate one or more implementation methods of this invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this invention, and these all fall within the protection scope of this invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A fully enclosed long-shaft submersible pump, characterized in that, The pump body (3) includes a support sleeve (1), a bearing seat (2) and a pump body (3) arranged sequentially from top to bottom. The pump body (3) has a centrifugal chamber (31), a suction end (32) and a discharge end (33). An impeller (34) is provided in the centrifugal chamber (31). A bushing (341) is provided on the impeller (34). The bushing (341) passes through the bearing seat (2) and extends into the support sleeve (1). A pump shaft (4) is provided in the support sleeve (1). One end of the pump shaft (4) is connected to the bushing (341). The bearing housing (2) is provided with a bearing (21) for connecting the bushing (341). The bottom of the bearing housing (2) is provided with a seal (22). A gap is formed between the seal (22) and the impeller (34). A pressure plate (23) is provided in the gap. A flexible member (24) is provided below the pressure plate (23). The flexible member (24) has an initial state and a working state. In the initial state, the top of the flexible member (24) does not contact the bottom of the pressure plate (23). In the working state, the top of the flexible member (24) contacts the bottom of the pressure plate (23) and pushes the pressure plate (23) towards the seal (22) until the top of the pressure plate (23) is in contact with the bottom of the seal (22), so that the seal (22) is subjected to an upward force.

2. The fully enclosed long-shaft submersible pump according to claim 1, characterized in that, The sealing element (22) is a combined sealing ring (221). The combined sealing ring (221) includes a polytetrafluoroethylene wear-resistant layer (2211) and a nitrile rubber elastic layer (2212) arranged sequentially from top to bottom. The bottom of the bearing seat (2) is provided with an annular sealing groove. The combined sealing ring (221) is embedded in the annular sealing groove. The top of the combined sealing ring (221) is in close contact with the bottom of the annular sealing groove.

3. The fully enclosed long-shaft submersible pump according to claim 1, characterized in that, The pressure plate (23) is a circular metal plate with a diameter that is consistent with the outer diameter of the bottom of the seal (22). The edge of the pressure plate (23) is provided with a guide boss (231). The inner wall of the pump body (3) is provided with a guide groove (35) that is adapted to the guide boss (231). The pressure plate (23) moves axially through the sliding fit between the guide boss (231) and the guide groove (35).

4. The fully enclosed long-shaft submersible pump according to claim 3, characterized in that, The top of the pressure plate (23) is provided with a circular mounting groove (232), and a circular rubber ring (233) that can fit with the bottom of the seal (22) is provided in the circular mounting groove (232).

5. A fully enclosed long-shaft submersible pump according to claim 1, characterized in that, The flexible component (24) is an annular rubber with a cavity. An annular frame (36) is provided inside the pump body (3) above the impeller (34). The inner and outer rings of the flexible component (24) are respectively provided on the annular frame (36). The material of the annular rubber is fluororubber.

6. A fully enclosed long-shaft submersible pump according to claim 5, characterized in that, The cavity of the flexible component (24) contains a medium (241).

7. A fully enclosed long-shaft submersible pump according to claim 1, characterized in that, The pump shaft (4) is provided with an external spline (41) at one end near the bushing (341), and the inner wall of the bushing (341) is provided with an internal spline (3411) that is adapted to the external spline (41). The pump shaft (4) and the bushing (341) are connected by spline engagement, and the mating surfaces of the pump shaft (4) and the bushing (341) are coated with a wear-resistant lubricating coating.

8. A fully enclosed long-shaft submersible pump according to claim 1, characterized in that, The upper part of the bearing seat (2) is constructed with an annular liquid collection cavity (25). The upper end of the bushing (341) passes through the annular liquid collection cavity (25) and extends into the interior of the support sleeve (1). A detector (26) and a water pumping pipe (27) are installed through the top of the bearing seat (2). The working end of the detector (26) and the working end of the water pumping pipe (27) extend to the deepest position of the annular liquid collection cavity (25) respectively.

9. A fully enclosed long-shaft submersible pump according to claim 8, characterized in that, The lower section of the annular liquid collection chamber (25) has a funnel-shaped cross-section.

10. A fully enclosed long-shaft submersible pump according to claim 8, characterized in that, The detector (26) is a liquid level sensor, and the detection end of the liquid level sensor is flush with the deepest position of the annular liquid collection cavity (25).

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