A self-coupling sealed submersible sewage pump

Abstract

The present invention belongs to the technical field of submersible sewage pumps, and discloses a self-coupling sealed submersible sewage pump, including a pump pipe and a water outlet pipe seat fixed at the bottom of a pool, and also includes: a moving surface in contact with the water flow, which is arranged in the pump pipe and the moving surface moves linearly along the water flow direction under the impact of the water flow; a driving rod, one end of which is connected to the moving surface and moves linearly along the water flow direction with the moving surface; a first internal thread shell, which is fixed in the pump pipe; a second internal thread shell, which is fixed in the water outlet pipe seat; two threaded barrels, which are respectively arranged on both sides of the internal thread in the first internal thread shell; the driving rod, the first internal thread shell, the second internal thread shell and the threaded barrel are arranged with a common central axis; a motion conversion mechanism, which is connected to the other end of the driving rod and fixed between the two threaded barrels. The present invention effectively solves the problems of looseness and poor sealing caused by vibration, and improves the sealing performance and working stability of the submersible sewage pump.

Description

Technical Field

[0001] The invention belongs to the technical field of submersible sewage pumps, in particular to a self-coupling sealed submersible sewage pump. Background Art

[0002] As a highly efficient sewage treatment equipment, submersible sewage pump has been widely used in industries, agriculture and urban drainage systems. It is mainly composed of two parts: a water outlet base and a submersible pump. The water outlet base is generally fixed in the sewage pool, and the submersible pump and the water outlet base are connected by a coupling structure. This design makes the installation, maintenance and disassembly of the submersible sewage pump easy, without the need for operators to go down to the sewage pool to perform operations.

[0003] In the existing technology, the coupling structure mainly completes the coupling operation under the gravity of the submersible pump. Specifically, during installation, the submersible pump only needs to be lowered along the guide rod to the position corresponding to the water outlet base, and the weight of the submersible pump itself is used to make the coupling structure tightly connected.

[0004] However, since the submersible sewage pump itself will vibrate to a certain extent during operation, this coupling structure that relies on gravity is easily affected by vibration and thus easily becomes loose, causing sewage to leak from the connection with the coupling structure, affecting the working stability of the submersible sewage pump. Therefore, it is necessary to improve the existing submersible sewage pump coupling connection structure to solve the problems of looseness, leakage and poor sealing caused by the vibration of the pump operation. Summary of the invention

[0005] In order to solve the problems raised in the above background technology, the present invention provides a self-coupling sealed submersible sewage pump.

[0006] To achieve the above object, the present invention provides the following technical solution: a self-coupling sealed submersible sewage pump, comprising a pump pipe and a water outlet pipe seat fixed at the bottom of a pool, and further comprising:

[0007] A moving surface in contact with the water flow is arranged in the pump pipe and moves linearly along the direction of the water flow under the impact of the water flow;

[0008] A driving rod, one end of which is connected to the moving surface and moves linearly along the water flow direction with the moving surface;

[0009] A first internally threaded shell is fixedly disposed in the pump pipe;

[0010] A second internally threaded shell is fixedly disposed in the water outlet pipe seat;

[0011] Two threaded barrels are respectively arranged on both sides of the internal thread in the first internal thread shell;

[0012] The driving rod, the first internal thread shell, the second internal thread shell and the threaded barrel are arranged on a common central axis;

[0013] A motion conversion mechanism is connected to the other end of the driving rod and fixed between the two threaded cylinders;

[0014] The driving rod moves linearly along the water flow direction to drive the motion conversion mechanism to drive the threaded barrel to helically displace in the direction toward the second internal threaded shell. As the two threaded barrels helically displace, they are respectively connected with the internal threads in the first internal threaded shell and the second internal threaded shell.

[0015] In the above technical solution, preferably, the moving surface includes a moving shell, which is slidably arranged on the outside of the first internally threaded shell, and the moving shell is in contact with the outer wall of the first internally threaded shell and the inner wall of the pump tube, and the moving surface also includes an extension plate arranged on the moving shell.

[0016] In the above technical solution, preferably, a cover plate is provided on the movable shell, and the cover plate is fitted with the inner wall of the pump pipe, when the pump pipe is fitted with the water outlet pipe seat, the first internal threaded shell is fitted with the second internal threaded shell, and the movable surface moves along the water flow direction to drive the cover plate to move and cover the fitting part between the pump pipe and the water outlet pipe seat, and the movable shell covers and seals the fitting part between the first internal threaded shell and the second internal threaded shell.

[0017] In the above technical solution, preferably, the driving rod passes through the first internal thread shell and is connected to the movable shell, and the movable shell moves along the water flow direction to drive the driving rod to move, and during the movement, the movable shell always covers the driving rod passing through the first internal thread shell.

[0018] In the above technical solution, preferably, the motion conversion mechanism includes a hollow cylinder, in which at least two motion tracks are arranged in a circular shape and equidistantly around the central axis of the cylinder, and balls are rolled in the motion tracks. The balls are arranged on a driving rod, and move in a straight line as driven by the driving rod. The balls roll along the motion tracks to drive the cylinder to spirally displace.

[0019] In the above technical solution, preferably, it also includes an arcuate surface and a gravity member, the arcuate surface is connected to the movable surface, the gravity member is movably arranged on the arcuate surface of the arcuate surface, and the top wall inside the pump tube is provided with a reset cavity for allowing the gravity member to move vertically and the arcuate surface to move horizontally.

[0020] In the above technical solution, preferably, the arc surface includes an arc block and a cover plate connected to the moving surface, the cover plate is in contact with the inner wall of the pump tube, the arc block is arranged in the reset cavity and passes through the inner wall of the pump tube and is connected to the cover plate, and the arc block and the cover plate move with the moving surface, and the cover plate always covers the arc block passing through the inner wall of the pump tube.

[0021] In the above technical solution, preferably, the gravity member includes a roller in contact with the arc surface of the arc surface, and the roller is rotatably arranged at one end of the counterweight block.

[0022] In the above technical solution, preferably, the moving surface, the driving rod, the first internal threaded shell, the second internal threaded shell, the two threaded barrels and the motion conversion mechanism are a group, and the number is not less than two groups, which are arranged equidistantly in a ring with the pump pipe and the water outlet pipe seat having the same central axis.

[0023] In the above technical solution, preferably, the driving rod in one group passes through one of the threaded barrels, and a shaft rod is provided in the first internal threaded shell, and the shaft rod passes through the driving rod and extends into another threaded barrel.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The moving surface in the present invention moves linearly in the direction of the water flow under the impact of the water flow, and the driving rod moves accordingly, thereby driving the threaded barrel to helically displace in the direction of the second internal threaded shell. Through the coordinated work of the driving rod, the motion conversion mechanism and the threaded barrel, a tight threaded connection between the pump pipe and the outlet pipe seat is achieved. Even under the vibration generated when the pump is running, the firmness of the connection can be maintained, effectively solving the problems of looseness and poor sealing caused by vibration, and improving the sealing performance and working stability of the submersible sewage pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A three-dimensional structural diagram of the connection between the pump pipe and the water outlet pipe seat of the present invention;

[0027] Figure 2 It is a front view of the pump pipe and the water outlet pipe seat of the present invention;

[0028] Figure 3 It is a cross-sectional structural diagram of the pump pipe and the water outlet pipe seat of the present invention;

[0029] Figure 4 The figure is a side view of the internal structure of the pump tube of the present invention;

[0030] Figure 5 It is a three-dimensional structural diagram of the moving surface, the first internal thread shell, the arc surface and the gravity member of the present invention;

[0031] Figure 6 It is a three-dimensional structural diagram of the moving surface and the arc surface of the present invention;

[0032] Figure 7 It is an exploded view of the internal structure of the first internal thread shell of the present invention;

[0033] Figure 8 It is a cross-sectional structural diagram of the movable shell and the first internal thread shell of the present invention;

[0034] Fig. 9It is a sectional three-dimensional structural diagram of the first internal thread shell of the present invention;

[0035] Fig.10 It is a three-dimensional cross-sectional view of the first internal thread shell and the shaft rod of the present invention.

[0036] In the figure: 1. pump pipe; 2. water outlet pipe seat; 3. moving surface; 31. moving shell; 32. extension plate; 33. cover plate; 4. driving rod; 5. first internal thread shell; 6. second internal thread shell; 7. threaded cylinder; 8. motion conversion mechanism; 81. cylinder; 82. motion track; 83. ball; 9. arc surface; 91. arc block; 92. cover plate; 10. gravity member; 101. roller; 102. counterweight block; 11. reset chamber; 12. shaft rod. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] like Figure 1 , Figure 2 , Figure 3 , Figure 7 and Fig. 9 As shown, the present invention provides a self-coupling sealed submersible sewage pump, comprising a pump pipe 1 and a water outlet pipe seat 2 fixedly arranged at the bottom of a pool, and further comprising:

[0039] The moving surface 3 in contact with the water flow is arranged in the pump pipe 1 and the moving surface 3 moves linearly along the direction of the water flow under the impact of the water flow;

[0040] A driving rod 4, one end of which is connected to the moving surface 3 and moves linearly along the water flow direction with the moving surface 3;

[0041] The first internal thread shell 5 is fixedly arranged in the pump tube 1;

[0042] The second internal thread shell 6 is fixedly arranged in the water outlet pipe seat 2;

[0043] Two threaded barrels 7 are respectively arranged on both sides of the internal thread in the first internal thread shell 5;

[0044] The driving rod 4, the first internal thread shell 5, the second internal thread shell 6 and the threaded barrel 7 are arranged with a common central axis;

[0045] The motion conversion mechanism 8 is connected to the other end of the driving rod 4 and is fixed between the two threaded cylinders 7;

[0046] Preferably, the motion conversion mechanism 8 is located in the internal thread of the first internal thread shell 5, and the connection between one threaded barrel 7 and the motion conversion mechanism 8 is arranged adjacent to the internal thread of the first internal thread shell 5, and the other threaded barrel 7 is arranged adjacent to the internal thread of the second internal thread shell 6 on the side away from the motion conversion mechanism 8;

[0047] This arrangement enables the threaded barrel 7 to be directly and smoothly connected to the internal threads of the first internal thread shell 5 and the second internal thread shell 6 under the drive of the motion conversion mechanism 8, thereby simplifying the docking process and improving the efficiency and accuracy of the connection;

[0048] The driving rod 4 moves linearly along the water flow direction to drive the motion conversion mechanism 8 to drive the threaded barrel 7 to helically displace toward the second internal thread shell 6. As the two threaded barrels 7 helically displace, they are threadedly connected with the internal threads in the first internal thread shell 5 and the second internal thread shell 6 respectively.

[0049] like Figure 4 , Figure 6 and Figure 8 As shown, the moving surface 3 includes a moving shell 31, which is slidably arranged outside the first internally threaded shell 5, and the moving shell 31 is in contact with the outer wall of the first internally threaded shell 5 and the inner wall of the pump tube 1, and the moving surface 3 also includes an extension plate 32 arranged on the moving shell 31;

[0050] The extension plate 32 is detachably mounted on the movable shell 31 and contacts the water flow first. The contact area between the extension plate 32 and the water flow is larger than the contact area between the movable shell 31 and the water flow. The extension plate 32 is selected according to different actual water flow velocities and pipe diameters to ensure that the movable shell 31 is driven to move along the water flow direction under the impact of the water flow. When the movable shell 31 can move under the impact of the water flow, the extension plate 32 may not be installed on the movable shell 31, which can be flexibly selected by users.

[0051] There is a spacing distance between the moving shell 31 and the first internally threaded shell 5 along the straight direction of the water flow. When the moving shell 31 moves the spacing distance to abut against the first internally threaded shell 5 or the internally threaded connection between the threaded barrel 7 and the second internally threaded shell 6 abuts against each other, the moving shell 31 stops moving and completes the locking operation.

[0052] like Figure 5 , Figure 6 and Figure 8 As shown, specifically, a cover plate 33 is provided on the movable shell 31, and the cover plate 33 is fitted with the inner wall of the pump pipe 1. When the pump pipe 1 is fitted with the water outlet pipe seat 2, the first internal thread shell 5 is fitted with the second internal thread shell 6. The movable surface 3 moves along the water flow direction to drive the cover plate 33 to move and cover the fitting part of the pump pipe 1 and the water outlet pipe seat 2, and the movable shell 31 covers and seals the fitting part of the first internal thread shell 5 and the second internal thread shell 6.

[0053] On the basis of realizing the tight threaded connection between the pump pipe 1 and the outlet pipe seat 2 by combining the synergistic effect of the threaded barrel 7 with the first internal threaded shell 5 and the second internal threaded shell 6, the movable shell 31 and the cover plate 33 further cover the connection. This double sealing design effectively prevents sewage leakage, effectively solves the problem of poor sealing, reduces the energy loss of the pump during operation, and improves the energy efficiency of the submersible sewage pump.

[0054] The driving rod 4 passes through the first internal thread shell 5 and is connected to the moving shell 31 . The moving shell 31 moves along the water flow direction to drive the driving rod 4 to move. During the movement, the moving shell 31 always covers the driving rod 4 passing through the first internal thread shell 5 .

[0055] The through-hole design of the driving rod 4: that is, the moving shell 31 slides on the first internally threaded shell 5, so that it is more stable when moving along the direction of the water flow, and is not easy to deviate or loosen, and the characteristics of the moving shell 31 are used to always cover the through-hole, and the moving shell 31 is combined to cover the connection point between the first internally threaded shell 5 and the second internally threaded shell 6, which effectively prevents sewage from leaking into the first internally threaded shell 5 and affecting the internal components, thereby extending the service life of this functional component.

[0056] like Figure 7 , Figure 8 and Fig. 9 As shown, the motion conversion mechanism 8 includes a hollow cylinder 81, in which at least two motion tracks 82 are arranged in a ring shape and equidistantly around the central axis of the cylinder 81, and balls 83 are rolled in the motion tracks 82. The balls 83 are arranged on the driving rod 4, and the balls 83 are driven by the driving rod 4 to move in a straight line. The balls 83 roll along the motion tracks 82 to drive the cylinder 81 to spirally move.

[0057] Among them, the rolling design of the ball 83 reduces the friction during the movement and reduces the energy loss. The design of rolling friction is more efficient. The rolling motion of the ball 83 on the motion track 82 has high precision, which can ensure that the linear motion of the drive rod 4 is accurately converted into the spiral displacement of the cylinder 81. The symmetrically arranged motion track 82 and the ball 83 make the cylinder 81 more stable during the spiral displacement and less likely to deviate or loosen, thereby ensuring the stable spiral displacement of the threaded cylinder 7.

[0058] As can be seen from the above, the present invention achieves a good sealing effect by threadedly locking the pump pipe 1 and the water outlet pipe seat 2 during the water flow process, but the existing self-coupling submersible sewage pump mainly uses a guide rod to couple the coupling structure of the self-coupling submersible pump with the self-coupling structure on the water outlet base to complete the placement of the submersible pump. When disassembling and maintaining, it is only necessary to directly lift the submersible pump, so the operation is simple and convenient. The locking structure of the present invention will hinder the quick disassembly and maintenance operations of the submersible pump.

[0059] Therefore, if Figure 3 , Figure 6and Figure 6 As shown, the following solutions are proposed for the above problems:

[0060] It also includes an arc surface 9 and a gravity member 10, the arc surface 9 is connected to the moving surface 3, the gravity member 10 is movably arranged on the arc surface of the arc surface 9, and the top wall of the pump tube 1 is provided with a reset cavity 11 for allowing the gravity member 10 to move vertically and the arc surface 9 to move horizontally;

[0061] When the submersible pump stops running for inspection or replacement, there is no water flowing in the pipeline, and the gravity of the gravity member 10 can automatically drive the arc surface 9 to move back to its original position, thereby driving the drive rod 4 to move back to its original position through the moving surface 3. The moving shell 31 and the cover plate 33 no longer cover the fitting part of the pump pipe 1 and the water outlet pipe seat 2, and the threaded connection between the pump pipe 1 and the water outlet pipe seat 2 is released. The gravity factor of the gravity member 10 is used to realize the automatic return function, reducing the need for manual intervention. The operator can complete the uncoupling and lifting operations of the submersible pump according to the normal process. This automatic return function ensures that the threaded connection locking component will not affect the normal inspection, maintenance and disassembly and assembly operations of the submersible pump.

[0062] The arc surface 9 includes an arc block 91 and a cover plate 92 connected to the moving surface 3. The cover plate 92 is in contact with the inner wall of the pump tube 1. The arc block 91 is arranged in the reset cavity 11 and penetrates the inner wall of the pump tube 1 and is connected to the cover plate 92. The arc block 91 and the cover plate 92 move with the moving surface 3. The cover plate 92 always covers the arc block 91 penetrating the inner wall of the pump tube 1.

[0063] The design of the cover plate 92 can effectively prevent sewage from leaking from the connection between the inner wall of the pump pipe 1 and the arc block 91, thereby ensuring the normal use of this functional component.

[0064] The gravity member 10 includes a roller 101 in contact with the arc surface of the arc surface 9 . The roller 101 is rotatably disposed at one end of the counterweight block 102 .

[0065] The counterweight 102 further comprises a frame, the roller 101 is arranged on the frame, the counterweight 102 is detachably arranged on the frame, and the counterweight 102 is selected according to different actual downward pressures. The gravity of the counterweight 102 helps to ensure that when the submersible pump is not flowing with water, the moving surface 3 and the driving rod 4 can automatically return to their original positions and release the threaded connection between the pump pipe 1 and the outlet pipe seat 2, so that the operator can perform normal inspection, maintenance and disassembly and assembly operations of the submersible pump;

[0066] Preferably, the moving surface 3, the driving rod 4, the first internal thread shell 5, the second internal thread shell 6, the two threaded barrels 7 and the motion conversion mechanism 8 form a group, and the number is not less than two groups, which are arranged equidistantly in a ring shape with the pump pipe 1 and the water outlet pipe seat 2 coaxially with the center axis.

[0067] The multi-group structure design provides more sealing contact surfaces, ensuring the sealing between the pump pipe and the outlet pipe seat, reducing the possibility of loosening and leakage, and enhancing the sealing performance. The multi-group structure can effectively disperse the vibration and load during the operation of the pump, thereby improving the stability of the entire mechanism;

[0068] like Fig.10 As shown, a driving rod 4 in a group passes through a threaded barrel 7 , and a shaft rod 12 is arranged in the first internal threaded shell 5 . The shaft rod 12 passes through the driving rod 4 and extends into another threaded barrel 7 .

[0069] The design of the shaft 12 passing through the drive rod 4 and the threaded barrel 7 ensures the precise guidance of the drive rod 4 and the threaded barrel 7 in the first internal threaded shell 5. This guiding design helps to maintain the stable position of the drive rod 4 and the threaded barrel 7, prevents them from shifting or loosening during operation, and improves the connection reliability and stability of the entire coupling structure.

[0070] The working principle and use process of the present invention:

[0071] The pump pipe 1 of the sewage pump is coupled and installed on the outlet pipe seat 2 to perform sewage discharge operation:

[0072] The water flows along the pump pipe 1 and the outlet pipe seat 2, and the water contacts and impacts the extension plate 32 and the moving shell 31, which moves in a straight line along the direction of the water flow. The moving shell 31 drives the driving rod 4, the covering plate 33 and the cover plate 92 to move in a straight line.

[0073] in:

[0074] The ball 83 at the end of the driving rod 4 rolls along the moving track 82 to drive the cylinder 81 to helical displacement, and the cylinder 81 drives the threaded cylinders 7 at both ends to helical displacement and respectively connect with the internal threads in the first internal thread shell 5 and the second internal thread shell 6;

[0075] The moving shell 31 and the cover plate 33 move toward the joint between the first internal thread shell 5 and the second internal thread shell 6 and the joint between the pump pipe 1 and the water outlet pipe seat 2;

[0076] The cover plate 92 drives the arc block 91 to move in a straight line, and the roller 101 moves vertically along the arc surface of the arc block 91 along the straight line displacement of the arc block 91, and drives the counterweight block 102 to be lifted synchronously at the same time;

[0077] When the movable shell 31 moves a distance to abut against the first internal thread shell 5 or the internal threads of the threaded barrel 7 and the second internal thread shell 6 are connected to abut against each other, the movable shell 31 stops moving, and the thread locking operation between the pump pipe 1 and the outlet pipe seat 2 is completed;

[0078] At the same time, when the movable shell 31 does not move any more, the movable shell 31 and the cover plate 33 have covered the joint between the first internal thread shell 5 and the second internal thread shell 6 and the joint between the pump pipe 1 and the water outlet pipe seat 2;

[0079] The arc block 91 stops moving accordingly, and the roller 101 stops on the arc surface of the arc block 91 .

[0080] The pump pipe 1 of the sewage pump is being maintained or replaced:

[0081] There is no water flowing in the pump pipe 1 and the outlet pipe seat 2. The weight of the counterweight block 102 drives the roller 101 to move along the arc surface of the arc block, thereby pushing the arc block 91 to move in a direction away from the outlet pipe seat 2. The arc block 91 drives the cover plate 92 to reset and move, and the cover plate 92 drives the moving shell 31, the cover plate 33 and the driving rod 4 to reset and move;

[0082] Move the movable shell 31 and the cover plate 33 in a direction away from the joint between the first internal thread shell 5 and the second internal thread shell 6 and the joint between the pump pipe 1 and the water outlet pipe seat 2;

[0083] The driving rod 4 drives the ball 83 to return and roll along the moving track 82 to drive the cylinder 81 to reverse spiral displacement, and the cylinder 81 drives the threaded cylinders 7 at both ends to reverse spiral displacement and release the threaded connection with the internal threads in the first internal thread shell 5 and the second internal thread shell 6 respectively;

[0084] When the roller 101 moves to the bottom surface of the arc block 91 and stops moving, that is, the movable shell 31 and the cover plate 33 move to no longer cover the joint between the first internal thread shell 5 and the second internal thread shell 6 and the joint between the pump pipe 1 and the outlet pipe seat 2, the threaded connection between the threaded barrel 7 and the first internal thread shell 5 and the second internal thread shell 6 is released;

[0085] The operator can lift the sewage pump to the designated position through the guide rod for maintenance and replacement.

[0086] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0087] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A self-coupling sealed submersible sewage pump, comprising a pump pipe (1) and a water outlet pipe seat (2) fixedly arranged at the bottom of a pool, characterized in that: Also includes: A moving surface (3) in contact with the water flow is arranged in the pump pipe (1), and the moving surface (3) moves linearly along the direction of the water flow under the impact of the water flow; A driving rod (4), one end of which is connected to the moving surface (3) and moves linearly along the direction of the water flow along with the moving surface (3); A first internally threaded shell (5) is fixedly disposed in the pump pipe (1); A second internally threaded shell (6) is fixedly disposed in the water outlet pipe seat (2); Two threaded barrels (7) are respectively arranged on both sides of the internal thread in the first internal thread shell (5); The driving rod (4), the first internal thread shell (5), the second internal thread shell (6) and the threaded cylinder (7) are arranged on a common central axis; A motion conversion mechanism (8) connected to the other end of the driving rod (4) and fixedly disposed between the two threaded cylinders (7); The driving rod (4) moves linearly along the direction of the water flow to drive the motion conversion mechanism (8) to drive the threaded barrel (7) to move helically in the direction toward the second internal thread shell (6). As the two threaded barrels (7) move helically, they are respectively connected to the internal threads in the first internal thread shell (5) and the second internal thread shell (6).

2. A self-coupling sealed submersible sewage pump according to claim 1, characterized in that: The moving surface (3) comprises a moving shell (31), the moving shell (31) being slidably arranged outside the first internally threaded shell (5), the moving shell (31) being in contact with the outer wall of the first internally threaded shell (5) and the inner wall of the pump tube (1), and the moving surface (3) further comprises an extension plate (32) arranged on the moving shell (31).

3. A self-coupling sealed submersible sewage pump according to claim 2, characterized in that: The movable shell (31) is provided with a cover plate (33), and the cover plate (33) is in contact with the inner wall of the pump pipe (1). When the pump pipe (1) is in contact with the water outlet pipe seat (2), the first internally threaded shell (5) is in contact with the second internally threaded shell (6). The movable surface (3) moves along the direction of water flow to drive the cover plate (33) to move and cover the contact point between the pump pipe (1) and the water outlet pipe seat (2). The movable shell (31) covers and seals the contact point between the first internally threaded shell (5) and the second internally threaded shell (6).

4. A self-coupling sealed submersible sewage pump according to claim 2, characterized in that: The driving rod (4) passes through the first internally threaded shell (5) and is connected to the moving shell (31); the moving shell (31) moves along the direction of the water flow to drive the driving rod (4) to move; during the movement, the moving shell (31) always covers the portion where the driving rod (4) passes through the first internally threaded shell (5).

5. The self-coupling sealed submersible sewage pump according to claim 1, characterized in that: The motion conversion mechanism (8) comprises a hollow cylinder (81), wherein at least two motion tracks (82) are arranged in a ring shape and equidistantly around the central axis of the cylinder (81), wherein balls (83) are arranged rollingly in the motion tracks (82), wherein the balls (83) are arranged on the driving rod (4), and are driven by the driving rod (4) to move along a straight line, and wherein the balls (83) roll along the motion tracks (82) to drive the cylinder (81) to move helically.

6. A self-coupling sealed submersible sewage pump according to claim 1, characterized in that: The pump tube (1) further comprises an arcuate surface (9) and a gravity member (10), wherein the arcuate surface (9) is connected to the movable surface (3), and the gravity member (10) is movably arranged on the arcuate surface of the arcuate surface (9). The inner top wall of the pump tube (1) is provided with a reset cavity (11) which allows the gravity member (10) to move vertically and the arcuate surface (9) to move horizontally.

7. A self-coupling sealed submersible sewage pump according to claim 6, characterized in that: The arc surface (9) comprises an arc block (91) and a cover plate (92) connected to the moving surface (3); the cover plate (92) is in contact with the inner wall of the pump tube (1); the arc block (91) is arranged in the reset cavity (11) and penetrates the inner wall of the pump tube (1) and is connected to the cover plate (92); as the moving surface (3) drives the arc block (91) and the cover plate (92) to move, the cover plate (92) always covers the arc block (91) penetrating the inner wall of the pump tube (1).

8. The self-coupling sealed submersible sewage pump according to claim 6, characterized in that: The gravity member (10) comprises a roller (101) in contact with the arc surface of the arc surface (9); the roller (101) is rotatably disposed at one end of the counterweight block (102).

9. A self-coupling sealed submersible sewage pump according to any one of claims 1 to 8, characterized in that: The moving surface (3), the driving rod (4), the first internal thread shell (5), the second internal thread shell (6), the two threaded barrels (7) and the motion conversion mechanism (8) form a group, and the number of the groups is not less than two, and the pump pipe (1) and the water outlet pipe seat (2) are arranged in a circular shape with equal distance from the central axis.

10. A self-coupling sealed submersible sewage pump according to claim 9, characterized in that: In one group, the driving rod (4) passes through one of the threaded barrels (7), and a shaft rod (12) is arranged inside the first internal threaded shell (5). The shaft rod (12) passes through the driving rod (4) and extends into another threaded barrel (7).

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