A multi-stage deep-well pump

Abstract

A multi-section deep well pump, comprising a base, a water outlet head above the base, and a impeller group between the base and the water outlet head, the impeller group is composed of an upper impeller unit, a lower impeller unit and a plurality of middle impeller units which are uniformly distributed between the upper impeller unit and the lower impeller unit in the axial direction; the water outlet head is arranged on the upper end of the upper impeller unit; the base is arranged on the lower end of the lower impeller unit; the lower end of the upper impeller unit and the middle impeller unit is provided with a lower connecting flange; the upper end of the lower impeller unit and the middle impeller unit is provided with an upper connecting flange; the upper connecting flange and the lower connecting flange are fixed through a fixing structure. The multi-section deep well pump can easily realize the fastening of the belt and effectively reduce the cost.

Description

Technical Field

[0001] This invention relates to the field of deep well pump technology, and in particular to a multi-stage deep well pump. Background Technology

[0002] A deep well pump is a common type of water pump used for extracting water from deep wells. It works by connecting a motor to the pump body and immersing it in deep well water. Deep well pumps are usually composed of multi-stage impellers; the more impeller stages, the higher the head.

[0003] In traditional deep well pumps, the multi-stage impellers located between the outlet head and the base are usually axially secured by a long, integral strap to ensure the tightness between the impeller housings of each stage. When the deep well pump has a large number of impeller stages, its overall length is extremely long, resulting in an extremely long strap. When the long strap is secured through the upper and lower ends, it is very difficult to tighten due to its excessive length, which can easily lead to loosening between the stacked impeller housings, affecting the sealing performance and working efficiency of the deep well pump.

[0004] At the same time, if the impeller casing outside the multi-stage impeller is simply fastened by the pull belt, a large number of pull belts are required to ensure the fastening pressure, which leads to a sharp increase in cost. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a multi-stage deep well pump that can not only easily achieve the fastening of the pull belt, but also effectively reduce costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention discloses a multi-stage deep well pump, comprising a base and a water outlet head located above the base. An impeller assembly is provided between the base and the water outlet head. The impeller assembly consists of an upper impeller unit, a lower impeller unit, and several intermediate impeller units axially and evenly distributed between the upper and lower impeller units. The water outlet head is located at the upper end of the upper impeller unit. The base is located at the lower end of the lower impeller unit. A lower connecting flange is provided at the lower end of each of the upper and intermediate impeller units. An upper connecting flange is provided at the upper end of each of the lower and intermediate impeller units. The upper and lower connecting flanges are fixed together by a fixing structure. The water outlet head is connected to the lower connecting flange at the lower end of the upper impeller unit, the upper connecting flange at the upper end of the intermediate impeller unit is connected to the lower connecting flange at the lower end of the intermediate impeller unit, and the upper connecting flange at the upper end of the lower impeller unit is connected to the base by several circumferentially evenly distributed straps.

[0007] The upper impeller unit includes an upper rotating shaft; the upper rotating shaft is provided with a plurality of upper impellers evenly distributed axially, and the upper impellers are covered with matching upper impeller shells, with adjacent upper impeller shells stacked on top of each other; the center of the water outlet head has a first annular bearing seat; a plurality of first support plates evenly distributed circumferentially are provided between the outer wall of the first bearing seat and the inner wall of the water outlet head; a first bushing fitted inside the first bearing seat is a first bushing fitted at the upper end of the upper rotating shaft.

[0008] The intermediate impeller unit includes an intermediate rotating shaft; the intermediate rotating shaft is provided with a plurality of intermediate impellers evenly distributed axially, and the intermediate impellers are covered by matching intermediate impeller shells, with adjacent intermediate impeller shells stacked on top of each other; the upper connecting flange has a second shaft seat in the center in an annular shape; a plurality of second support plates evenly distributed circumferentially are provided between the outer wall of the second shaft seat and the inner wall of the center of the upper connecting flange; a second shaft sleeve fitted outside the intermediate rotating shaft is provided in the second shaft seat located at the center of the upper connecting flange at the upper end of the intermediate impeller unit.

[0009] The lower impeller unit includes a lower rotating shaft; the lower rotating shaft is provided with a plurality of lower impellers evenly distributed in the axial direction, and the lower impellers are covered by matching lower impeller shells, with adjacent lower impeller shells stacked on top of each other; a third shaft sleeve is provided in the second shaft seat located at the center of the upper connecting flange at the upper end of the lower impeller unit and fitted outside the lower rotating shaft.

[0010] The lower ends of the upper shaft, middle shaft, and lower shaft are all equipped with couplings; the inner wall of the lower end of the coupling is provided with a spline groove; the upper ends of the middle shaft and lower shaft are each provided with a spline head; the outer wall of the upper end of the spline head is provided with spline teeth that match the spline groove.

[0011] The fixing structure includes a lower flange on the lower outer wall of the lower connecting flange and an upper flange on the upper outer wall of the upper connecting flange; the lower flange has a plurality of first through holes evenly distributed in a circle, and the upper flange has a plurality of second through holes coaxial with the first through holes; a fixing bolt passes through the first through holes and the second through holes and is screwed with a fixing nut, and both the upper flange and the lower flange are located between the head of the fixing bolt and the fixing nut.

[0012] The outer wall of the lower connecting flange and the outer wall of the base are both provided with a first locking plate; the outer wall of the upper connecting flange is provided with a second locking plate; the first locking plate is provided with a plurality of first locking holes evenly distributed in a circle; the second locking plate is provided with a plurality of second locking holes corresponding to the positions of the first locking holes; the upper end of the pull belt distributed on the outer ring of the middle impeller unit and the lower impeller unit is provided with an upper fastening screw, the upper fastening screw passes upward through the second locking hole and is screwed with an upper fastening nut that fits against the upper surface of the second locking plate; the lower end of the pull belt distributed on the outer ring of the upper impeller unit, the middle impeller unit and the lower impeller unit is provided with a lower fastening screw, the lower fastening screw passes downward through the first locking hole and is screwed with a lower fastening nut that fits against the lower surface of the first locking plate.

[0013] The upper outer wall of the water outlet head is provided with an annular protrusion; the outer wall of the annular protrusion is provided with several fixing grooves evenly distributed in a circle; the upper end face of the annular protrusion is provided with several locking holes that communicate with the upper end of the fixing groove; the lower side wall of the fixing groove is provided with a locking groove; the upper end of the pull belt distributed on the outer ring of the upper impeller unit passes through the fixing groove and enters into the locking hole; the lower end of a limiting block is locked in the locking groove, and the part of the pull belt that passes through the fixing groove is clamped between the upper end face of the limiting block and the upper side wall of the fixing groove.

[0014] A sleeve outside the pull belt is provided between the lower connecting flange between the water outlet head and the lower end of the upper impeller unit, between the upper connecting flange at the upper end of the middle impeller unit and the lower connecting flange at the lower end of the middle impeller unit, and between the upper connecting flange at the upper end of the lower impeller unit and the base.

[0015] Both the outer wall of the outlet head and the outer wall of the upper connecting flange are provided with an upper limit plate; the lower end of the lower limit tube is screwed to the outside of the first locking plate, and the inner wall of the upper end of the lower limit tube is provided with an annular lower limit groove; a locking tube is screwed to the outer side of the upper end of the upper limit tube, and the inner wall of the lower end of the upper limit tube is provided with an annular lower limit groove; the upper end of the sleeve is locked in the upper limit groove, and the lower end of the sleeve is locked in the lower limit groove; the inner edge of the upper end of the locking tube extends inward to form a limiting ring that fits against the upper surface of the upper limit plate; the lower surface of the limiting ring is provided with an annular sealing groove, and a sealing ring is provided in the sealing groove.

[0016] The present invention has the following beneficial effects: Compared with existing technologies, the multi-segment deep well pump using the structure of this invention divides the traditional integral impeller assembly into multiple independent units such as the upper impeller unit, the middle impeller unit, and the lower impeller unit. This transforms the original single long tension belt into a short tension belt for each unit, effectively reducing the length of a single tension belt. With the significant reduction in tension belt length, it can be easily tightened when the tension belt is fastened at both ends, avoiding the situation where the impeller shell becomes loose due to difficulty in tightening the tension belt caused by excessive length. This effectively ensures the axial sealing performance and structural stability of the deep well pump.

[0017] Compared with the prior art, the multi-stage deep well pump with the structure of the present invention adds a rigid sleeve to the outer ring of the pull belt of each impeller unit. Therefore, even if the pull belt loosens during long-term use, the sleeve can still ensure the axial fastening pressure between the impeller shells of each stage. In addition, the introduction of the sleeve can appropriately reduce the number of pull belts, effectively reducing material costs while ensuring the fastening pressure.

[0018] Compared with the prior art, the multi-stage deep well pump with the structure of this invention has independent pull belt and casing structures for the upper impeller unit, middle impeller unit and lower impeller unit. Therefore, when a problem occurs in a certain unit, the maintenance personnel only need to disassemble the pull belt and casing of the corresponding unit to carry out repair and replacement without disassembling the entire deep well pump. This improves maintenance efficiency and effectively reduces maintenance costs. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of a first embodiment of the multi-stage deep well pump of the present invention; Figure 2 yes Figure 1 An enlarged view of part A; Figure 3 yes Figure 1 An enlarged view of part B; Figure 4 This is a partial cross-sectional view of a first embodiment of the multi-stage deep well pump of the present invention; Figure 5 This is a schematic diagram of the structure of a first embodiment of the multi-stage deep well pump of the present invention; Figure 6 This is a schematic diagram of the outlet head of the multi-stage deep well pump according to Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the upper connecting flange of Embodiment 1 of the multi-section deep well pump of the present invention; Figure 8 This is a cross-sectional view of Embodiment 2 of the multi-stage deep well pump of the present invention; Figure 9 yes Figure 8 Enlarged view of part C; Figure 10 yes Figure 8 An enlarged view of part D; Figure 11 This is a schematic diagram of the structure of Embodiment 2 of the multi-stage deep well pump of the present invention. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Example 1, please refer to Figures 1 to 7This invention provides a multi-stage deep well pump, including a base 1, a water outlet 2 located above the base 1, and an impeller assembly between the base 1 and the water outlet 2. The impeller assembly consists of an upper impeller unit 3, a lower impeller unit 5, and several intermediate impeller units 4 evenly distributed axially between the upper impeller unit 3 and the lower impeller unit 5. The water outlet 2 is located at the upper end of the upper impeller unit 3; the base 1 is located at the lower end of the lower impeller unit 5; and both the upper impeller unit 3 and the intermediate impeller units 4 have a lower impeller assembly at their lower ends. A connecting flange 6 is provided at the upper end of both the lower impeller unit 5 and the middle impeller unit 4; the upper connecting flange 7 and the lower connecting flange 6 are fixed together by a fixing structure; the water outlet 2 is connected to the lower connecting flange 6 at the lower end of the upper impeller unit 3, the upper connecting flange 7 at the upper end of the middle impeller unit 4 is connected to the lower connecting flange 6 at the lower end of the middle impeller unit 4, and the upper connecting flange 7 at the upper end of the lower impeller unit 5 is connected to the base 1 by several circumferentially evenly distributed straps 8.

[0021] The upper impeller unit 3 includes an upper rotating shaft 301; the upper rotating shaft 301 is provided with a plurality of upper impellers 302 evenly distributed axially, and the upper impellers 302 are covered with matching upper impeller shells 303, with adjacent upper impeller shells 303 stacked; the outlet head 2 has a first annular bearing 9 at its center; a plurality of first support plates 10 evenly distributed circumferentially are provided between the outer wall of the first bearing 9 and the inner wall of the outlet head 2; a first bushing 11 fitted inside the first bearing 9 and attached to the upper end of the upper rotating shaft 301 is provided; the gap between adjacent first support plates 10 allows water flow.

[0022] The intermediate impeller unit 4 includes an intermediate shaft 401; the intermediate shaft 401 is provided with a plurality of intermediate impellers 402 evenly distributed axially, and the intermediate impellers 402 are covered by matching intermediate impeller shells 403, with adjacent intermediate impeller shells 403 stacked; the upper connecting flange 7 has a second shaft seat 12 in the center of the ring; a plurality of second support plates 13 evenly distributed circumferentially are provided between the outer wall of the second shaft seat 12 and the inner wall of the center of the upper connecting flange 7; a second shaft sleeve 14 is provided inside the second shaft seat 12 at the center of the upper connecting flange 7 at the upper end of the intermediate impeller unit 4, which is fitted outside the intermediate shaft 401; the gap between adjacent second support plates 13 allows water flow.

[0023] The lower impeller unit 5 includes a lower rotating shaft 501; the lower rotating shaft 501 is provided with a plurality of lower impellers 502 evenly distributed axially, and the lower impellers 502 are covered with matching lower impeller shells 503, with adjacent lower impeller shells 503 stacked; a third bushing 15 is provided in the second shaft seat 12 located at the center of the upper connecting flange 7 at the upper end of the lower impeller unit 5, which is fitted outside the lower rotating shaft 501. The third bushing 15, the second bushing 14 and the first bushing 11 can all be made of tungsten steel, which not only has wear-resistant properties, but also ensures the smoothness of the rotation of the upper rotating shaft 301, the middle rotating shaft 401 and the lower rotating shaft 501.

[0024] The lower ends of the upper rotating shaft 301, the middle rotating shaft 401, and the lower rotating shaft 501 are all provided with couplings 16; the inner wall of the lower end of the coupling 16 is provided with a spline groove 17; the upper ends of the middle rotating shaft 401 and the lower rotating shaft 501 are all provided with a spline head 18; the outer wall of the upper end of the spline head 18 is provided with spline teeth 19 that match the spline groove 17; the cooperation between the spline groove 17 and the spline teeth 19 can ensure the synchronicity of the upper rotating shaft 301, the middle rotating shaft 401, and the lower rotating shaft 501. When the lower rotating shaft 501 is connected to the motor shaft of the motor through the coupling 16, the upper rotating shaft 301, the middle rotating shaft 401, and the lower rotating shaft 501 rotate synchronously as the motor shaft rotates.

[0025] The fixing structure includes a lower flange 20 located on the outer wall of the lower end of the lower connecting flange 6 and an upper flange 21 located on the outer wall of the upper end of the upper connecting flange 7. The lower flange 20 has a plurality of first through holes 22 evenly distributed in a circle, and the upper flange 21 has a plurality of second through holes 23 coaxial with the first through holes 22. A fixing bolt 24 passes through the first through holes 22 and the second through holes 23 and is screwed with a fixing nut 25. The upper flange 21 and the lower flange 20 are both located between the head of the fixing bolt 24 and the fixing nut 25. This fixing method not only ensures the stability between the upper flange 21 and the lower flange 20, but also facilitates their disassembly and assembly. Simply unscrew the fixing nut 25 from the fixing bolt 24 to separate the upper flange 21 and the lower flange 20, thereby enabling the quick disassembly of the upper connecting flange 7 and the lower connecting flange 6. At the same time, O-rings, gaskets, and other sealing structures can be installed on the wall surfaces where the upper flange 21 and the lower flange 20 fit together, effectively ensuring the sealing performance when the upper connecting flange 7 and the lower connecting flange 6 are connected.

[0026] The outer walls of the lower connecting flange 6 and the base 1 are both provided with first locking plates 26; the outer walls of the upper connecting flange 7 are provided with second locking plates 27; the first locking plates 26 are provided with a plurality of first locking holes 28 evenly distributed in a circle; the second locking plates 27 are provided with a plurality of second locking holes 29 corresponding to the positions of the first locking holes 28; the upper ends of the pull belts 8 distributed on the outer rings of the middle impeller unit 4 and the lower impeller unit 5 are each provided with an upper fastening screw 30, the upper fastening screw 30 passes upward through the second locking holes 29 and is screwed with an upper fastening nut 31 that fits against the upper surface of the second locking plate 27; the upper impeller unit 3 and the middle impeller unit 4 are provided with a pull belt 8 evenly distributed in a circle. The lower end of the pull belt 8 on the outer ring of the lower impeller unit 5 is provided with a lower fastening screw 32. The lower fastening screw 32 passes downward through the first locking hole 28 and is screwed with a lower fastening nut 33 that fits against the lower surface of the first locking plate 26. The upper fastening screw 30 and the upper fastening nut 31 can not only fix the upper end of the pull belt 8 to the second locking plate 27, but also further tighten the upper end of the pull belt 8 by rotating the upper fastening nut 31. The lower fastening screw 32 and the lower fastening nut 33 can not only fix the lower end of the pull belt 8 to the first locking plate 26, but also further tighten the lower end of the pull belt 8 by rotating the lower fastening nut 33, thus maximizing the fastening pressure of the pull belt 8.

[0027] The upper outer wall of the water outlet head 2 is provided with an annular protrusion 34; the outer wall of the annular protrusion 34 is provided with several circumferentially evenly distributed fixing grooves 35; the upper end face of the annular protrusion 34 is provided with several locking holes 36 that communicate with the upper end of the fixing grooves 35; the lower side wall of the fixing grooves 35 is provided with locking grooves 37; the upper end of the pull belt 8 distributed on the outer ring of the upper impeller unit 3 passes through the fixing grooves 35 and enters into the locking holes 36; the lower end of a limiting block 38 is locked in the locking groove 37, and the part of the pull belt 8 that passes through the fixing grooves 35 is clamped between the upper end face of the limiting block 38 and the upper side wall of the fixing groove 35; this structural design not only ensures the stability of the upper end of the pull belt 8 fixed on the water outlet head 2, but also facilitates disassembly. After the lower fastening screw 32 and the lower fastening nut 33 at the lower end of the pull belt 8 are separated, the limiting block 38 can be taken out from the locking groove 37, and the upper end of the pull belt 8 can be quickly disassembled.

[0028] Example 2, please refer to Figures 8 to 11 A sleeve 39 is provided outside the pull belt 8 between the lower connecting flange 6 between the water outlet head 2 and the lower end of the upper impeller unit 3, between the upper connecting flange 7 at the upper end of the middle impeller unit 4 and the lower connecting flange 6 at the lower end of the middle impeller unit 4, and between the upper connecting flange 7 at the upper end of the lower impeller unit 5 and the base 1.

[0029] Both the outer wall of the water outlet 2 and the outer wall of the upper connecting flange 7 are provided with an upper limit plate 40; the lower end of the lower limit tube 42 is screwed to the outside of the first locking plate 26, and the inner wall of the upper end of the lower limit tube 42 is provided with an annular lower limit groove 43; a locking tube 45 is screwed to the outer side of the upper end of an upper limit tube 44, and the inner wall of the lower end of the upper limit tube 44 is provided with an annular lower limit groove 43; the upper end of the sleeve 39 is locked in the upper limit groove 46, and the lower end of the sleeve 39 is locked in the lower limit groove 43; the inner edge of the upper end of the locking tube 45 extends inward to form a limiting ring 47 that fits against the upper surface of the upper limit plate 40; the lower surface of the limiting ring 47 is provided with an annular sealing groove 48, and a sealing ring 49 is provided in the sealing groove 48; the presence of the sealing ring 49 can effectively ensure the sealing between the lower surface of the limiting ring 47 and the upper surface of the upper limit plate 40, and effectively prevent water leakage.

[0030] The method of using this invention is as follows: The present invention divides the impeller assembly into three groups: upper impeller unit 3, lower impeller unit 5, and middle impeller unit 4. Each group has its own pull belt 8, thereby transforming the original single pull belt into multiple short pull belts. This effectively reduces the length of each pull belt, so when the upper and lower ends of the pull belt 8 are fixed, it can be easily tightened without the situation where the stacked impeller shells become loose due to their excessive length.

[0031] Furthermore, this invention adds a sleeve 39 to the outside of the pull belt 8. The sleeve 39 is a steel pipe structure, unlike the pull belt, and has extremely high rigidity. The upper limit tube 44 and the lower limit tube 42 limit and fix the sleeve 39, allowing the sleeve 39 to be stably fitted onto the outer ring of the pull belt 8. Therefore, even if the pull belt 8 becomes loose, the sleeve 39 can ensure the tightness between the stacked impeller shells and guarantee the fastening pressure. At the same time, the upper impeller unit 3, the lower impeller unit 5, and the middle impeller unit 4 each have their own unique sleeve 39. Therefore, when one of the impeller units malfunctions... When a problem occurs, only the casing 39 and the pull belt 8 of the impeller unit need to be disassembled, which facilitates maintenance and effectively avoids the situation where a whole long casing encloses the impeller unit 3, the lower impeller unit 5 and the middle impeller unit 4, which would require the entire deep well pump to be disassembled during maintenance. In addition, with the presence of the casing 39, the number of pull belts 8 can be reduced. For example, if only pull belts 8 are used for fastening, 8 pull belts are required. With the casing 39, the number of pull belts can be reduced to 4, which effectively reduces material costs while ensuring the fastening pressure.

Claims

1. A multi-stage deep well pump, comprising a base, a water outlet head located above the base, and an impeller assembly disposed between the base and the water outlet head, characterized in that: The impeller assembly consists of an upper impeller unit, a lower impeller unit, and several intermediate impeller units evenly distributed axially between the upper and lower impeller units. The water outlet is located at the upper end of the upper impeller unit; the base is located at the lower end of the lower impeller unit; both the upper and intermediate impeller units have a lower connecting flange at their lower ends; both the lower and intermediate impeller units have an upper connecting flange at their upper ends; the upper and lower connecting flanges are fixed together by a fixing structure; the water outlet is connected to the lower connecting flange at the lower end of the upper impeller unit, the upper connecting flange at the upper end of the intermediate impeller unit is connected to the lower connecting flange at the lower end of the intermediate impeller unit, and the upper connecting flange at the upper end of the lower impeller unit is connected to the base by several evenly distributed circumferential straps.

2. A multi-stage deep well pump according to claim 1, characterized in that: The upper impeller unit includes an upper rotating shaft; the upper rotating shaft is provided with a plurality of upper impellers evenly distributed axially, and the upper impellers are covered with matching upper impeller shells, with adjacent upper impeller shells stacked on top of each other; the center of the water outlet head has a first annular bearing seat; a plurality of first support plates evenly distributed circumferentially are provided between the outer wall of the first bearing seat and the inner wall of the water outlet head; a first bushing fitted inside the first bearing seat is a first bushing fitted at the upper end of the upper rotating shaft.

3. A multi-stage deep well pump according to claim 2, characterized in that: The intermediate impeller unit includes an intermediate rotating shaft; the intermediate rotating shaft is provided with a plurality of intermediate impellers evenly distributed axially, and the intermediate impellers are covered by matching intermediate impeller shells, with adjacent intermediate impeller shells stacked on top of each other; the upper connecting flange has a second shaft seat in the center in an annular shape; a plurality of second support plates evenly distributed circumferentially are provided between the outer wall of the second shaft seat and the inner wall of the center of the upper connecting flange; a second shaft sleeve fitted outside the intermediate rotating shaft is provided in the second shaft seat located at the center of the upper connecting flange at the upper end of the intermediate impeller unit.

4. A multi-stage deep well pump according to claim 3, characterized in that: The lower impeller unit includes a lower rotating shaft; the lower rotating shaft is provided with a plurality of lower impellers evenly distributed in the axial direction, and the lower impellers are covered by matching lower impeller shells, with adjacent lower impeller shells stacked on top of each other; a third shaft sleeve is provided in the second shaft seat located at the center of the upper connecting flange at the upper end of the lower impeller unit and fitted outside the lower rotating shaft.

5. A multi-stage deep well pump according to claim 4, characterized in that: The lower ends of the upper shaft, middle shaft, and lower shaft are all equipped with couplings; the inner wall of the lower end of the coupling is provided with a spline groove; the upper ends of the middle shaft and lower shaft are each provided with a spline head; the outer wall of the upper end of the spline head is provided with spline teeth that match the spline groove.

6. A multi-stage deep well pump according to claim 1, characterized in that: The fixing structure includes a lower flange on the lower outer wall of the lower connecting flange and an upper flange on the upper outer wall of the upper connecting flange; the lower flange has a plurality of first through holes evenly distributed in a circle, and the upper flange has a plurality of second through holes coaxial with the first through holes; a fixing bolt passes through the first through holes and the second through holes and is screwed with a fixing nut, and both the upper flange and the lower flange are located between the head of the fixing bolt and the fixing nut.

7. A multi-stage deep well pump according to claim 6, characterized in that: The outer wall of the lower connecting flange and the outer wall of the base are both provided with a first locking plate; the outer wall of the upper connecting flange is provided with a second locking plate; the first locking plate is provided with a plurality of first locking holes evenly distributed in a circle; the second locking plate is provided with a plurality of second locking holes corresponding to the positions of the first locking holes; the upper end of the pull belt distributed on the outer ring of the middle impeller unit and the lower impeller unit is provided with an upper fastening screw, the upper fastening screw passes upward through the second locking hole and is screwed with an upper fastening nut that fits against the upper surface of the second locking plate; the lower end of the pull belt distributed on the outer ring of the upper impeller unit, the middle impeller unit and the lower impeller unit is provided with a lower fastening screw, the lower fastening screw passes downward through the first locking hole and is screwed with a lower fastening nut that fits against the lower surface of the first locking plate.

8. A multi-stage deep well pump according to claim 1, characterized in that: The upper outer wall of the water outlet head is provided with an annular protrusion; the outer wall of the annular protrusion is provided with several fixing grooves evenly distributed in a circle; the upper end face of the annular protrusion is provided with several locking holes that communicate with the upper end of the fixing groove; the lower side wall of the fixing groove is provided with a locking groove; the upper end of the pull belt distributed on the outer ring of the upper impeller unit passes through the fixing groove and enters into the locking hole; the lower end of a limiting block is locked in the locking groove, and the part of the pull belt that passes through the fixing groove is clamped between the upper end face of the limiting block and the upper side wall of the fixing groove.

9. A multi-stage deep well pump according to claim 7, characterized in that: A sleeve outside the pull belt is provided between the lower connecting flange between the water outlet head and the lower end of the upper impeller unit, between the upper connecting flange at the upper end of the middle impeller unit and the lower connecting flange at the lower end of the middle impeller unit, and between the upper connecting flange at the upper end of the lower impeller unit and the base.

10. A multi-stage deep well pump according to claim 9, characterized in that: Both the outer wall of the outlet head and the outer wall of the upper connecting flange are provided with an upper limit plate; the lower end of the lower limit tube is screwed to the outside of the first locking plate, and the inner wall of the upper end of the lower limit tube is provided with an annular lower limit groove; a locking tube is screwed to the outer side of the upper end of the upper limit tube, and the inner wall of the lower end of the upper limit tube is provided with an annular lower limit groove; the upper end of the sleeve is locked in the upper limit groove, and the lower end of the sleeve is locked in the lower limit groove; the inner edge of the upper end of the locking tube extends inward to form a limiting ring that fits against the upper surface of the upper limit plate; the lower surface of the limiting ring is provided with an annular sealing groove, and a sealing ring is provided in the sealing groove.

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