A corrosion-resistant submersible pump for wells

Abstract

This invention relates to the field of submersible pump technology, specifically a corrosion-resistant submersible pump for wells. It includes a casing, a pump barrel fixedly connected to the top of the casing, a base at the bottom of the casing, a wound stator core inside the casing, and a rotor inside the casing. An end cover is located on the top of the pump barrel, and a cable for supplying power to the wound stator core is located on the side wall of the pump barrel. An insulation layer is provided between the cable and the pump barrel, with sealant applied to both sides of the insulation layer. A protective sleeve is wrapped around the side of the cable away from the insulation layer, and a pressure plate is located on the side of the protective sleeve away from the insulation layer. This invention, by providing an insulation layer between the cable and the pump barrel, filling both sides of the insulation layer with sealant, and then pressing the cable, sealant, insulation layer, and pump barrel together with a pressure plate, effectively avoids galvanic corrosion of the pump barrel caused by cable leakage current and crevice corrosion, thereby extending the service life of the submersible pump.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of submersible electric pumps, in particular to a corrosion-resistant submersible electric pump for wells. BACKGROUND

[0002] The submersible electric pump for wells is an important equipment for deep well water extraction. When in use, the entire electric pump is submerged in water for operation, and the underground well water is transported to the water use point through the operation of the electric pump. The submersible electric pump is an essential equipment for domestic water, farmland irrigation, industrial cooling, etc.

[0003] The submersible electric pump for wells has a wide application field and complex and variable working conditions. The physical and chemical properties of the pumped medium are different in different regions. In some working conditions, the medium extracted by the submersible electric pump is rich in silt; in some working conditions, it is rich in minerals or alkaline ions; and in some working conditions, it is close to the sea and the medium is rich in chloride ions, which has a certain corrosive property.

[0004] Among them, when the submersible electric pump for wells is applied to the seawater breeding working condition, the well water is mixed with seawater. Compared with ordinary fresh water medium, seawater is rich in chloride ions and has a certain corrosive property, and is also a natural electrolyte, which can quickly corrode the charged accessory parts of the product, such as the casing of the submersible electric motor for wells and the pump cylinder. Among them, the pump cylinder in contact with the cable line is often first corroded and perforated, causing functional failure, greatly shortening the service life of the submersible electric pump for wells, and bringing inconvenience and economic cost burden to the user.

[0005] And when the submersible electric pump is used in seawater, the corrosion between the cable line and the pump cylinder is usually caused by crevice corrosion. Crevice corrosion refers to the local electrochemical corrosion of metal components caused by the stagnation of medium in the gap (0.025-0.1mm) in the corrosive medium. The stagnation of corrosive medium in the gap leads to the imbalance of electrochemical environment, causing local corrosion of the metal in the gap. The essence is that the oxygen concentration difference between the inside and outside of the gap forms a concentration cell, and the area inside the gap becomes the anode and accelerates the dissolution. The medium flows smoothly outside the gap, and the oxygen concentration is high; while the medium stagnates inside the gap, the oxygen is gradually depleted, forming a potential difference, and then forming an oxygen concentration difference cell. At the same time, the dissolution of metal ions in the gap causes the hydrolysis reaction to lower the pH value (as low as 2-3), further damaging the passivation film.

[0006] Therefore, a corrosion-resistant submersible electric pump for wells is proposed to solve the problem that the submersible electric pump is easily corroded when used in seawater. SUMMARY

[0007] The present application aims to provide a corrosion-resistant submersible electric pump for wells, which solves the problem that the submersible electric pump is easily corroded when used in seawater, and improves the service life of the submersible electric pump.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0009] The utility model provides a kind of corrosion-resistant well submersible electric pump, including shell, the top of the shell is fixedly connected with pump barrel, the bottom of the shell is provided with base, the inside of the shell is provided with winding stator core, the both ends of the winding stator core are winding wire package, the inside of the shell is also provided with rotor matched with winding stator core, the rotor is fixedly connected with pump shaft, the pump shaft extends into the inside of pump barrel, the lower of the rotor is provided with bearing seat, the inside of the bearing seat is provided with bearing, the inner ring of the bearing is fixedly connected with the bottom of pump shaft, the top of the pump barrel is provided with end cover, the end cover is formed with discharge chamber between the pump barrel, the inside of the pump barrel is provided with impeller for pumping water, the impeller is fixedly connected with pump shaft, the lateral wall of the pump barrel is also provided with cable for supplying power to winding stator core, the cable is provided with insulating layer between the pump barrel, the both sides of the insulating layer are provided with sealant, the side of the cable away from the insulating layer is covered with protective sleeve, protective sleeve is made of rubber material, the side of the protective sleeve away from the insulating layer is provided with pressing plate, the pressing plate is connected with end cover, the pressing plate is used to press tightly protective sleeve, cable, insulating layer and sealant towards the direction of pump barrel, to prevent gap between cable and pump barrel.

[0010] Increase insulating layer between cable and pump barrel, reduce the leakage current of cable to pump barrel, prevent battery effect between pump barrel and cable due to current, prevent pump barrel from being corroded. Meanwhile, sealant is coated on both sides of the insulating layer, so that cable and insulating layer, insulating layer and pump barrel are tightly attached, to prevent gap between cable and pump barrel, further avoid gap corrosion. Effectively improve the service life of pump barrel, and further improve the service life of the whole submersible electric pump.

[0011] Preferably, the protective sleeve is provided with two limiting protrusions, the two limiting protrusions are spaced apart, and the two limiting protrusions are located at the top end and the bottom end of the pressing plate respectively, and the two limiting protrusions are used to prevent the relative displacement of the protective sleeve and the pressing plate in the axial direction of the cable. The limiting protrusion can always fix and press one part of the cable, avoid the change of pressing position of the cable due to the relative movement between the pressing plate and the cable, and further cause the decrease of corrosion prevention effect, effectively guarantee the use stability of the pressing plate and the corrosion prevention effect.

[0012] Preferably, the pressing plate comprises an arc-shaped piece and two extrusion parts, the two extrusion parts are spaced apart, the arc-shaped piece is located between the two extrusion parts for connecting the two extrusion parts, the side of the extrusion part away from the arc-shaped piece is provided with a clamping groove matched with the protective sleeve, and the two extrusion parts are further connected with a flexible part, the flexible part is located on the side of the extrusion part away from the arc-shaped piece, and the left and right sides of the pressing plate are provided with flexible sealing pieces, each sealing piece is connected to the two extrusion parts, the arc-shaped piece, the flexible part, the two sealing pieces and the two extrusion parts cooperatively form a closed space, each extrusion part is provided with a guide part, and the two guide parts are located at the ends of the two extrusion parts away from each other, each limiting protrusion is provided with an extrusion arc surface, and the two extrusion arc surfaces correspond to the two guide parts respectively.

[0013] In use, the submersible electric pump is submerged in water, the pressure inside the closed space is different from the water pressure, when the water pressure is greater than the air pressure inside the closed space, the arc-shaped piece will be extruded towards the protective sleeve, when the arc-shaped piece is extruded towards the protective sleeve, the arc-shaped piece pushes the two extrusion parts to move away from each other. Since the flexible part is made of flexible material and the sealing piece is also made of flexible material, the movement of the extrusion parts away from each other will not interfere with the flexible part and the sealing piece. During the process of the extrusion parts moving away from each other, the guide part at the end of the extrusion part extrudes the extrusion arc surface on the limiting protrusion, the extrusion arc surface is extruded and deformed towards the cable and the insulation layer, thereby pressing the cable and the insulation layer more tightly towards the pump barrel, avoiding the occurrence of gaps between the sealant, the insulation layer and the cable caused by water pressure. Further avoid the occurrence of corrosion gap.

[0014] Preferably, the arc-shaped piece is provided with a push block, the push block is located inside the closed space, each extrusion part is provided with a guide slope, the two guide slopes are located on the opposite sides of the two extrusion parts, and the two sides of the push block are provided with guide slopes corresponding to the two guide slopes. When the arc-shaped piece is extruded by the water pressure towards the protective sleeve, the guide slopes extrude the guide slopes and push the two extrusion parts away from each other.

[0015] The arrangement of the push block improves the stability of the arc-shaped piece pushing the two extrusion parts after being subjected to water pressure, so that the two extrusion parts can stably move along the axis direction of the cable, avoiding the situation that the two extrusion parts cannot be stably pushed away from each other due to insufficient strength and support of the arc-shaped piece, and ensuring the stability of the pressing plate in use.

[0016] Preferably, the arc-shaped piece and the extrusion part are made of stainless steel material, the side of the extrusion part towards the protective sleeve is provided with a lubricating part, the lubricating part is made of plastic material, and the lubricating part and the extrusion part are connected by adhesive.

[0017] The arc-shaped sheet and the extrusion part are used for long-term immersion in water, and the arc-shaped sheet and the extrusion part need to be stably connected, and the arc-shaped sheet needs to be deformed, so it is more reasonable to use stainless steel material and adopt the welding mode to connect the arc-shaped sheet and the extrusion part, and the service life is longer. If the arc-shaped sheet and the extrusion part are made of plastic material, they are easy to age and become brittle after long-term immersion in water, and the arc-shaped sheet will be broken when it is deformed under water pressure, causing the pressure plate to fail.

[0018] When the lubricating part made of plastic material contacts the protective sleeve made of rubber material, underwater friction can achieve self-lubricating effect, which helps the arc-shaped sheet to drive the extrusion part to move along the axis direction of the cable after being extruded by water pressure.

[0019] Since the protective sleeve is made of rubber material and the lubricating part is made of plastic material, there will be no gap corrosion between the two non-metallic materials. If the extrusion part directly abuts against the protective sleeve, the metal-made extrusion part will abut against the protective sleeve, and a gap will be generated between them, which is easy to cause gap corrosion and corrode the extrusion part. The lubricating part and the metal-made extrusion part are connected by gluing, which is more tightly connected than abutting and is not easy to cause gap corrosion.

[0020] Preferably, the flexible part is multi-layered, and the multi-layered flexible parts are installed at intervals, and both ends of each flexible part are used to connect two extrusion parts.

[0021] The flexible part is an important component of the sealed space, and its integrity and connection sealing are crucial. Since the flexible part is located on the side close to the protective sleeve, it will inevitably be in friction contact with the protective sleeve during use, and will eventually be damaged by friction. When the flexible part is damaged, liquid will flow into the sealed space, and the internal and external pressure difference effect cannot be formed, resulting in failure of the arc-shaped sheet. By adding multiple flexible parts, the airtightness of the sealed space is effectively ensured, the use effect of the pressure plate is effectively ensured, and the anti-corrosion effect on the pump cylinder is further ensured.

[0022] Preferably, the machine shell is provided with an upper insulating sleeve and a lower insulating sleeve, the upper insulating sleeve is arranged at the top end of the stator core with windings, and the upper insulating sleeve is used to isolate the winding wire package at the top end of the stator core with windings from the machine shell, and the lower insulating sleeve is arranged at the bottom end of the stator core with windings, and the lower insulating sleeve is used to isolate the winding wire package at the bottom end of the stator core with windings from the machine shell.

[0023] The upper and lower insulation sleeves isolate the winding wire package from the shell, which helps to prevent the leakage current generated by the winding wire package from contacting the shell when the motor is running, prevents the current from being conducted to the shell and then to the pump cylinder, prevents the formation of a small current loop between the shell, the pump cylinder and the anions in the seawater, forms a battery effect, and further causes electrochemical corrosion of the motor shell. Further, the corrosion of the shell and the pump cylinder is avoided, and the service life of the equipment is further improved.

[0024] Preferably, the shell, pump cylinder, end cover and base are made of stainless steel material, and the shell, pump cylinder, end cover and base are subjected to pickling and passivation process to form a passivation film on the surface of the stainless steel parts, thereby improving the corrosion resistance of the stainless steel parts to acid and alkali and prolonging the service life of the shell, pump cylinder, end cover and base.

[0025] Preferably, the upper and lower insulation sleeves are made of polypropylene plastic material. The polypropylene (PP) plastic material has strong insulation performance and is economical and practical, which can reduce the production cost while ensuring the insulation effect.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] 1. The corrosion-resistant submersible electric pump designed in the present application is provided with an insulation layer between the cable and the pump cylinder, and the insulation layer is filled with sealing glue on both sides, and the cable, sealing glue and pump cylinder are pressed tightly by a pressing block. Through the superposition of double measures, the galvanic corrosion and crevice corrosion coupling of the pump cylinder caused by the leakage current of the cable are effectively avoided, and the service life of the submersible electric pump is improved.

[0028] 2. The corrosion-resistant submersible electric pump designed in the present application is further provided with upper and lower insulation sleeves for isolating the winding wire package of the top surface and bottom surface of the stator core from the shell, thereby avoiding the galvanic corrosion or promoting crevice corrosion caused by the current conduction to the shell and pump cylinder during the use of the submersible electric pump, further improving the service life of the shell and pump cylinder, and further improving the overall service life of the submersible electric pump.

[0029] 3. The corrosion-resistant submersible electric pump designed in the present application is provided with a pressing plate divided into an arc-shaped piece and two separated extrusion parts, and a sealing space is formed in the pressing plate. The water pressure extrudes the arc-shaped piece to push the two extrusion parts to extrude the extrusion arc surface on the limiting protrusion block, so that the cable and the sealing glue between the submersible electric pump and the sealing glue and the pump cylinder are more tightly attached as the submersible electric pump goes deeper into the water, avoiding the water pressure extrusion to cause the sealing glue to open, and further avoiding the formation of crevice to cause crevice corrosion. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a schematic view of the internal structure of the present application;

[0031] Figure 2 Enlarged view of A in the present invention Figure 1

[0032] Figure 3 Enlarged view of B in the present invention Figure 1

[0033] Figure 4 Perspective view of the pressure plate in the present invention

[0034] Figure 5 Front view of the pressure plate in the present invention

[0035] Figure 6 Sectional view of C-C in the present invention Figure 5

[0036] Sectional view of D-D in the present invention Figure 7 Figure 5 Enlarged view of E in the present invention

[0037] Figure 8 Figure 6

[0038] In the figure: 1, the casing; 2, the pump cylinder; 3, the base; 4, the stator core with winding; 5, the winding wire package; 6, the rotor; 7, the pump shaft; 8, the bearing seat; 9, the bearing; 10, the end cover; 11, the discharge chamber; 12, the impeller; 13, the cable; 14, the insulation layer; 15, the sealing glue; 16, the protective sleeve; 17, the pressure plate; 1701, the arc piece; 1702, the extrusion part; 1703, the flexible part; 1704, the sealing piece; 18, the limiting bump; 19, the clamping groove; 20, the closed space; 21, the guide part; 22, the extrusion camber; 23, the push block; 24, the guide slope; 25, the guide slope; 26, the lubricating part; 27, the upper insulation sleeve; 28, the lower insulation sleeve; 29, the connecting plate; 30, the bolt hole. DETAILED DESCRIPTION

[0039] Referring to Figures 1 to 8 , the present application provides a corrosion-resistant submersible electric pump for wells, and the technical scheme is as follows:

[0040] A corrosion-resistant submersible electric pump for wells, referring to Figures 1 to 3 ​​​​​, including the shell 1, the shell 1 top fixedly connected with pump cylinder 2, the shell 1 bottom is provided with base 3, the shell 1 inside is provided with winding stator core 4, winding stator core 4 both ends are provided with winding wire package 5, the shell 1 inside is still provided with the rotor 6 matched with winding stator core 4, the rotor 6 is fixedly connected with motor shaft, the motor shaft is fixedly connected with pump shaft 7 through the nipple again, pump shaft 7 extends into the inside of pump cylinder 2, the rotor 6 below is provided with bearing seat 8, bearing seat 8 inside is provided with bearing 9, the inner ring of bearing 9 is fixedly connected with pump shaft 7 bottom, the top of pump cylinder 2 is provided with end cover 10, end cover 10 and pump cylinder 2 between form extrusion chamber 11, pump cylinder 2 inside is provided with for pumping out the impeller 12 of water pump, impeller 12 is fixedly connected with pump shaft 7, pump cylinder 2 side wall is still provided with the cable 13 for the power supply of winding stator core 4, the cable 13 and pump cylinder 2 between are provided with insulation layer 14, insulation layer can select PP, PET or PTFE and so on, also can select other such as ceramic and so on with good insulating property material. The both sides of insulation layer 14 are provided with sealing glue 15, sealing glue can select such as special silicone sealant, polyurethane glue or corrosion-resistant epoxy resin. The side of cable 13 away from insulation layer 14 is covered with protective sleeve 16, the side of protective sleeve 16 away from insulation layer 14 is provided with pressing plate 17.

[0041] Reference Figure 2 , the protective sleeve 16 is provided with two limit blocks 18, two limit blocks 18 are spaced apart, two limit blocks 18 are located at the top end and bottom end of pressing plate 17 respectively, two limit blocks 18 are used to prevent the relative displacement of protective sleeve 16 and pressing plate 17 in the axial direction of cable 13.

[0042] Reference Figure 2 And Figures 4 to 7The pressing plate 17 comprises an arc-shaped sheet 1701 and two extrusion portions 1702 which are arranged at intervals. The arc-shaped sheet 1701 and the extrusion portions 1702 are made of stainless steel. The extrusion portions 1702 are provided with lubricating portions 26 on the side facing the protective sleeve 16. The lubricating portions 26 are made of plastic material and are connected to the extrusion portions 1702 by gluing. The arc-shaped sheet 1701 is arranged between the two extrusion portions 1702 to connect the two extrusion portions 1702. The extrusion portions 1702 are provided with clamping grooves 19 which are matched with the protective sleeve 16 on the side away from the arc-shaped sheet 1701. The two extrusion portions 1702 are further connected by flexible portions 1703 which are arranged on the side of the extrusion portions 1702 away from the arc-shaped sheet 1701. The flexible portions 1703 are multi-layered and are arranged at intervals. The two ends of each layer of the flexible portions 1703 are used to connect the two extrusion portions 1702. The pressing plate 17 is provided with flexible sealing sheets 1704 on the left and right sides. Each of the flexible sealing sheets 1704 is connected to the two extrusion portions 1702. The arc-shaped sheet 1701, the flexible portions 1703, the two flexible sealing sheets 1704 and the two extrusion portions 1702 jointly form a closed space 20. The air pressure in the closed space 20 is one standard atmosphere. Each of the extrusion portions 1702 is provided with a guide portion 21 on the end away from the other extrusion portion 1702. Each of the limiting protrusions 18 is provided with an extrusion arc face 22. The two extrusion arc faces 22 are respectively matched with the two guide portions 21.

[0043] With reference to Figure 2 and Figure 6 , Figure 8 The arc-shaped sheet 1701 is further provided with a push block 23 which is arranged in the closed space 20. The two extrusion portions 1702 are respectively provided with guide slopes 24 on the opposite sides. The two sides of the push block 23 are provided with guide slopes 25 which are matched with the guide slopes 24. When the arc-shaped sheet 1701 is extruded by the water pressure towards the protective sleeve 16, the guide slopes 25 extrude the guide slopes 24 and push the two extrusion portions 1702 away from each other.

[0044] With reference to Figure 2 The left and right sides of the arc-shaped sheet 1701 are further provided with connecting plates 29. The connecting plates 29 are provided with bolt holes 30. The pressing plate 17 is connected to the end cover 10 by bolts which pass through the bolt holes 30.

[0045] In addition, the casing 1, the pump barrel 2, the end cover 10 and the base 3 are made of stainless steel. The casing 1, the pump barrel 2, the end cover 10 and the base 3 are subjected to pickling and passivation processes to form passivation films on the surfaces of the stainless steel parts. The passivation films effectively prevent the casing 1, the pump barrel 2, the end cover 10 and the base 3 from being corroded.

[0046] Referring to Figure 3 , the inside of the casing 1 is provided with an upper insulating sleeve 27 and a lower insulating sleeve 28, the upper insulating sleeve 27 is arranged at the top end of the stator core with windings 4, the upper insulating sleeve 27 is used to isolate the winding wire package 5 at the top end of the stator core with windings 4 from the casing 1, the lower insulating sleeve 28 is arranged at the bottom end of the stator core with windings 4, the lower insulating sleeve 28 is used to isolate the winding wire package 5 at the bottom end of the stator core with windings 4 from the casing 1. The upper insulating sleeve 27 and the lower insulating sleeve 28 are both made of polypropylene plastic material.

[0047] Before use, referring to Figure 4 , the pressing plate 17 is fixedly connected to the end cover 10 by bolts, so that the pressing plate 17 keeps extruding the protective sleeve 16 towards the pump cylinder 2.

[0048] During use, referring to Figures 1 to 7 , when the submersible electric pump is submerged in seawater, the current flowing through the cable 13 will not be conducted to the pump cylinder 2 under the isolation of the insulating layer 14 and the sealing glue 15, so as not to form galvanic corrosion to the pump cylinder 2. Under the adhesion of the sealing glue 15, the insulating layer 14 is tightly connected with the pump cylinder 2 without gap corrosion, and under the extrusion of the pressing plate 17, the gap between the insulating layer 14 and the pump cylinder 2 is further prevented, so as to prevent the gap corrosion between the pump cylinder 2 and the insulating layer 14.

[0049] At the same time, referring to Figure 1 , Figure 2 and Figures 4 to 7 , as the submersible electric pump continues to sink to the bottom of the water, the water pressure will extrude the arc-shaped piece 1701 on the pressing plate 17, the arc-shaped piece 1701 deforms towards the protective sleeve 16 after being pressed, the push block 23 inside the sealed space moves towards the protective sleeve 16 together with the arc-shaped piece 1701, the two guide slopes 25 on the push block 23 extrude the guide slopes 24 on the two extrusion parts 1702 respectively, the two extrusion parts 1702 move away from each other along the axis direction of the cable 13, the flexible part 1703 and the sealing piece 1704 elastically deform. While the two extrusion parts 1702 move away from each other, the guide parts 21 on the two extrusion parts 1702 extrude the extrusion arc surfaces 22 respectively, the protective sleeve 16 is further extruded and deformed towards the pump cylinder 2 after the extrusion arc surfaces 22 are extruded, so that the cable 13, the insulating layer 14, the sealing glue 15 and the pump cylinder 2 are more tightly fitted, preventing the sealing glue 15 from opening and forming a gap under the action of water pressure, further avoiding the gap corrosion of the pump cylinder 2, and ensuring the service life of the submersible electric pump.

[0050] At the same time, referring to Figure 3When the submersible electric pump is powered, the upper insulating sleeve 27 and the lower insulating sleeve 28 isolate the winding wire package 5 from the casing 1, which helps prevent the electric arc generated by the winding wire package 5 when the rotor 6 rotates under power from contacting the casing 1, preventing the conduction of electric current to the casing 1 and then to the pump cylinder 2. The formation of a small current loop between the casing 1, the pump cylinder 2 and the anions in the seawater is prevented, a battery effect is formed, and further electrochemical corrosion of the motor casing 1 is caused. Further, the corrosion of the casing 1 and the pump cylinder 2 is avoided, and the service life of the equipment is further improved.

[0051] The above describes one specific embodiment of the present application in detail in combination with the drawings, but the present application is not limited to the above-described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments without departing from the principles and ideas of the present application shall still fall within the protection scope of the present application.

Claims

1. A kind of corrosion-resistant well submersible motor pump, including casing (1), the pump cylinder (2) is fixedly connected to the top of the casing (1), the base (3) is provided at the bottom of the casing (1), the inside of the casing (1) is provided with winding stator core (4), the inside of the casing (1) is also provided with the rotor (6) matched with winding stator core (4), the pump shaft (7) is connected to the rotor (6), the pump shaft (7) extends into the inside of pump cylinder (2), the top of the pump cylinder (2) is provided with end cover (10), the end cover (10) and pump cylinder (2) form the discharge chamber (11) between, the pump cylinder (2) is provided with impeller (12) for pumping water in, the impeller (12) is fixedly connected with pump shaft (7), the sidewall of the pump cylinder (2) is also provided with cable (13) for supplying power to winding stator core (4), it is characterized by, The cable line (13) is provided with an insulation layer (14) between the pump cylinder (2), both sides of the insulation layer (14) are provided with sealing glue (15), the side of the cable line (13) away from the insulation layer (14) is covered with a protective sleeve (16), the side of the protective sleeve (16) away from the insulation layer (14) is provided with a pressing plate (17), the pressing plate (17) is connected with the end cover (10), the pressing plate (17) is used for pressing the protective sleeve (16), the cable line (13), the insulation layer (14) and the sealing glue (15) towards the direction of the pump cylinder (2), so as to prevent the gap between the cable line (13) and the pump cylinder (2), the protective sleeve (16) is provided with two limiting blocks (18), the two limiting blocks (18) are spaced apart, the two limiting blocks (18) are respectively located at the top end and the bottom end of the pressing plate (17), the two limiting blocks (18) are used for preventing the relative displacement of the protective sleeve (16) and the pressing plate (17) in the axial direction of the cable line (13), the pressing plate (17) comprises an arc-shaped sheet (1701) and two extrusion parts (1702), the two extrusion parts (1702) are spaced apart, the arc-shaped sheet (1701) is located between the two extrusion parts (1702) and is used for connecting the two extrusion parts (1702), the side of the extrusion part (1702) away from the arc-shaped sheet (1701) is provided with a clamping groove (19) matched with the protective sleeve (16), the two extrusion parts (1702) are further connected with a flexible part (1703), the flexible part (1703) is located on the side of the extrusion part (1702) away from the arc-shaped sheet (1701), the pressing plate (17) is provided with flexible sealing sheets (1704) on the left and right sides, each sealing sheet (1704) is connected to the two extrusion parts (1702), the arc-shaped sheet (1701), the flexible part (1703), the two sealing sheets (1704) and the two extrusion parts (1702) jointly form a closed space (20), each extrusion part (1702) is provided with a guide part (21), the two guide parts (21) are located at the ends of the two extrusion parts (1702) away from each other, each limiting block (18) is provided with an extrusion arc surface (22), and the two extrusion arc surfaces (22) correspond to the two guide parts (21) respectively.

2. The corrosion-resistant submersible electric pump for a well according to claim 1, characterized in that The arc-shaped sheet (1701) is provided with a push block (23), the push block (23) is located inside the closed space (20), the two extrusion parts (1702) are provided with guide slopes (24), the two guide slopes (24) are located on the opposite sides of the two extrusion parts (1702), the two sides of the push block (23) are provided with guide slopes (25) corresponding to the two guide slopes (24), when the arc-shaped sheet (1701) is extruded by water pressure towards the protective sleeve (16), the guide slopes (25) extrude the guide slopes (24) and push the two extrusion parts (1702) away from each other.

3. The corrosion-resistant submersible electric pump for a well according to claim 1, characterized in that, The arc-shaped sheet (1701) and the extruding part (1702) are made of stainless steel material, the extruding part (1702) is provided with a lubricating part (26) on the side facing the protective sleeve (16), the lubricating part (26) is made of plastic material, and the lubricating part (26) and the extruding part (1702) are connected by glue joint.

4. The corrosion-resistant submersible electric pump for a well according to claim 1, characterized in that, The flexible part (1703) is multi-layer, and the multi-layer flexible parts (1703) are installed at intervals, and the two ends of each layer of the flexible part (1703) are used for connecting two extruding parts (1702).

5. The corrosion-resistant submersible electric pump for a well according to claim 1, characterized in that, The inside of the machine shell (1) is provided with an upper insulating sleeve (27) and a lower insulating sleeve (28), the upper insulating sleeve (27) is arranged at the top end of the stator core (4) with windings, the upper insulating sleeve (27) is used for isolating the winding wire package (5) at the top end of the stator core (4) with windings from the machine shell (1), and the lower insulating sleeve (28) is arranged at the bottom end of the stator core (4) with windings, and the lower insulating sleeve (28) is used for isolating the winding wire package (5) at the bottom end of the stator core (4) with windings from the machine shell (1).

6. The corrosion-resistant submersible electric pump for a well according to claim 1, characterized in that, The machine shell (1), the pump cylinder (2), the end cover (10) and the base (3) are made of stainless steel material, and the machine shell (1), the pump cylinder (2), the end cover (10) and the base (3) are all treated by pickling and passivation process to form a passivation film on the surface of the stainless steel parts.

7. A corrosion resistant submersible electric pump for wells according to claim 5, characterized in that, The upper insulating sleeve (27) and the lower insulating sleeve (28) are made of polypropylene plastic material.

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