A multi-stage mixed flow pump casing connection structure and mixed flow pump

Abstract

The present invention discloses a multi-stage mixed pump casing connection structure and a mixed pump, which relate to the technical field of conveying pump equipment, and include an upper plate body fixed to a pump frame and a lower plate body fixed to a motor frame, and also include a connecting pipe. Both the upper plate body and the lower plate body are provided with a pipe joint structure adapted to be plugged with the connecting pipe. The upper plate body and the lower plate body are connected by a clamping and locking mechanism. The present invention achieves fixation by clamping the connecting pipe between the upper plate body and the lower plate body. This method is simple to operate and has stable locking, which is beneficial to greatly reducing the number of bolts.

Description

Technical Field

[0001] The invention relates to the technical field of delivery pump equipment, and in particular to a multi-stage mixed delivery pump casing connection structure and a mixed delivery pump. Background Art

[0002] A multistage mixed pump is a type of centrifugal pump. It combines two or more centrifugal pumps with the same function to form a multistage structure to handle the transportation of liquids or gas-liquid mixtures with different properties. It has the advantages of high head capacity, good stability, energy saving and high efficiency, and a wide range of applications. It plays an important role in many industrial fields.

[0003] Existing mixed flow pumps, such as the Chinese patent publication number: CN112524042B, the name of the patent is "a multi-stage mixed flow pump for deep sea mining", the patent includes "motor connecting frame, connecting pipe, submersible motor, pump connecting frame, inlet pump cover, coupling, rotor components, first-stage guide body, intermediate pump cover 1, secondary guide body, intermediate pump cover 2, final guide body, guide bearing, outlet pump cover, cylinder and pump stop protection device, which not only solves the wear problem of the submersible motor housing, but also increases the service life of the rotor components of the mixed flow pump";

[0004] In the technical solution of the mixed flow pump mentioned above, the motor connecting frame and the machine pump connecting frame are both provided with a diversion channel connected to the connecting pipe, and the connecting pipe and the motor connecting frame and the machine pump connecting frame are connected and fixed by flanges and multiple bolts, thereby forming a diversion pump shell of the multi-stage mixed flow pump on the outside of the submersible pump body. The disadvantage of this method is that, on the one hand, a large number of bolts are required and the installation space is limited. On the other hand, once the bolts are rusted, it also causes great inconvenience for the disassembly and maintenance of the diversion pump shell. In order to solve the above problems, we propose a multi-stage mixed flow pump shell connection structure and a mixed flow pump. Summary of the invention

[0005] The object of the present invention is to provide a multi-stage mixed flow pump casing connection structure and a mixed flow pump to solve the deficiencies in the above-mentioned prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A multi-stage mixed pump housing connection structure, comprising an upper plate fixed to a pump frame and a lower plate fixed to a motor frame, and also comprising a connecting pipe, wherein both the upper plate and the lower plate are provided with a pipe joint structure adapted to be plugged with the connecting pipe, and the upper plate and the lower plate are connected by a clamping and locking mechanism, and the clamping and locking mechanism comprises:

[0008] The insertion assembly comprises two mounting openings symmetrically provided on the upper plate body, each of the mounting openings is provided with a connecting column fixed to the lower plate body, and the connecting column is provided with a force receiving opening;

[0009] The force-applying assembly comprises a cam block located in the force-receiving opening, a driving shaft rotatably connected to the upper plate body being fixedly penetrated through the side surface of the cam block, and force arm rods connected to the driving shaft are symmetrically arranged on both sides of the connecting column, and the force arm rods have a pressing position and a releasing position in their movement stroke, and when the force arm rods are in the pressing position, an extrusion state is formed between the upper plate body and the lower plate body to apply pressure to the end of the connecting pipe.

[0010] Preferably, the pipe joint structure includes plug-in ports respectively located on the upper plate body and the lower plate body, and a step groove is provided on the inner wall of each of the plug-in ports, and a bridging conduction unit adapted to the end of the connecting pipe is provided in the step groove.

[0011] Preferably, the bridging conductive unit includes a conductive tube, the inner wall surface of the conductive tube is composed of a first inner diameter portion, a second inner diameter portion and a third inner diameter portion continuously distributed, the inner wall of the second inner diameter portion is a conical surface, and the inner wall surface of the second inner diameter portion is connected to the outer wall surface of the connecting tube end through a threaded structure.

[0012] Preferably, a plurality of evenly distributed clamping grooves are provided on the groove side wall surface of the step groove, and a clamping block connected to the outer wall surface of the second inner diameter portion is adapted to be clamped in each of the clamping grooves.

[0013] Preferably, the threaded structure includes a screw tooth structure located on the inner wall of the second inner diameter portion and a spiral structure located on the outer end portion of the connecting pipe, the spiral structure is a conical spiral structure, the screw tooth structure includes an insertion hole opened on the inner wall of the second inner diameter portion, the screw tooth structure also includes a block movably passing through the insertion hole, and the end of the block extending into the second inner diameter portion can engage and slide in a spiral manner with the spiral structure.

[0014] Preferably, an elastic sealing gasket is provided between the bottom wall of the step groove and the outside of the conducting pipe.

[0015] Preferably, when the lever arm is in the pressed position, the lever body is inclined at an acute angle to the horizontal plane, and the bottom end of the lever body of the lever arm in the pressed position can be locked and limited with the bottom end of the lever arm adjacent to the mirror image.

[0016] Preferably, a sleeve is slidably sleeved on the tube body of the connecting tube, and protruding rods are fixed on both sides of the sleeve. The lever arm can contact one of the protruding rods when in the pressed position, and the component of the force exerted by the lever arm on the protruding rod is the same as the force exerted on the connecting tube in the direction of screwing it onto the bridging conduction unit.

[0017] Preferably, the lever arm comprises a lever arm tube fixed to the driving shaft, and an extension rod capable of contacting the protruding rod is movably inserted inside the lever arm tube.

[0018] Preferably, the mixed flow pump is provided with the above-mentioned multi-stage mixed flow pump housing connection structure.

[0019] In the above technical scheme, the present invention provides a multi-stage mixed pump casing connection structure, which reduces the spacing between the upper plate body and the lower plate body by setting a clamping and locking mechanism between the upper plate body and the lower plate body, thereby clamping the connecting pipe between the upper plate body and the lower plate body to achieve fixation. This method is simple to operate and has stable locking, which is beneficial to greatly reduce the number of bolt parts, and is also convenient for disassembly and maintenance, simplifies the operating steps and reduces the difficulty of disassembly and assembly. The structure is simple and stable, and is also beneficial to overcome the problem that the bolts are rusted and cannot be disassembled. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a schematic diagram of the positions of the upper plate body and the lower plate body of a multi-stage mixed pump casing connection structure on the pump body of the present invention;

[0022] Figure 2 It is an overall schematic diagram of a multi-stage mixed pump casing connection structure of the present invention;

[0023] Figure 3 For the present invention Figure 2 Schematic diagram of the cross section of AA;

[0024] Figure 4 It is a cross-sectional schematic diagram of a lever arm of a multi-stage mixed pump casing connection structure of the present invention;

[0025] Figure 5 The present invention is a schematic cross-sectional view of a casing of a multi-stage mixed flow pump housing connection structure.

[0026] Description of reference numerals:

[0027] 1. Upper plate; 2. Lower plate; 3. Pipe joint structure; 3.1. Plug port; 3.2. Step groove; 3.21. Card slot; 3.22. Card block; 3.3. Bridge conduction unit; 3.31. Conducting pipe; 3.32. First inner diameter portion; 3.33. Second inner diameter portion; 3.34. Third inner diameter portion; 3.35. Thread structure; 3.351. Screw tooth structure; 3.3511. Plug hole; 3.352. Spiral structure; 3.4. Elastic sealing gasket; 4. Insertion component; 4.1. Installation port; 4.2. Connecting column; 4.3. Force port; 5. Force-applying component; 5.1. Cam block; 5.2. Drive shaft; 5.3. Lever rod; 5.31. Lever tube; 5.32. Extension rod; 5.33. Block; 5.34. Block ring; 5.35. First notch; 5.36. Second notch; 6. Connecting tube; 6.1. Sleeve; 6.2. Protruding rod; 6.3. Reinforcing ribs. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] See also Figure 1-5 The embodiment of the present invention provides a multi-stage mixed pump housing connection structure, including an upper plate body 1 fixed to a pump frame and a lower plate body 2 fixed to a motor frame, and also includes a connecting pipe 6. The upper plate body 1 and the lower plate body 2 are both provided with a pipe joint structure 3 adapted to be plugged with the connecting pipe 6. The upper plate body 1 and the lower plate body 2 are connected by a clamping and locking mechanism, and the clamping and locking mechanism includes:

[0030] The insertion assembly 4 comprises two installation openings 4.1 symmetrically provided on the upper plate body 1, each installation opening 4.1 is provided with a connecting column 4.2 fixed to the lower plate body 2, and a force receiving opening 4.3 is provided on the connecting column 4.2;

[0031] The force-applying assembly 5 comprises a cam block 5.1 located in the force-receiving opening 4.3, a driving shaft 5.2 rotatably connected to the upper plate body 1 is fixedly penetrated through the side of the cam block 5.1, and a lever arm 5.3 connected to the driving shaft 5.2 is symmetrically arranged on both sides of the connecting column 4.2, and the lever arm 5.3 has a pressing position and a discharging position in its movement stroke. When the lever arm 5.3 is in the pressing position, an extrusion state is formed between the upper plate body 1 and the lower plate body 2 to apply pressure to the end of the connecting pipe 6;

[0032] Specifically, a spacing space is formed between the upper plate body 1 and the lower plate body 2 in the vertical direction, the plate surfaces of the upper plate body 1 and the lower plate body 2 are parallel to the horizontal plane, the axis of the connecting pipe 6 is perpendicular to the plate surfaces of the upper plate body 1 and the lower plate body 2, and the connecting pipe 6 is connected with the pipeline on the pump frame and the pipeline structure on the motor frame through the pipe joint structure 3 to form a guide channel, the number of connecting pipes 6 is not less than two, the number of mounting ports 4.1 is at least two, and the two mounting ports 4.1 are symmetrically distributed at both ends of the midline of the upper plate body 1, the axis of the connecting column 4.2 is parallel to the horizontal plane, and the connecting column 4.2 is The bottom end is vertically fixed to the plate surface of the lower plate body 2, the force-bearing opening 4.3 is located above the upper plate body 1, the wheel plate surface of the cam block 5.1 is perpendicular to the horizontal plane, the top of the cam block 5.1 is in contact with the inner top of the force-bearing opening 4.3, the axis of the drive shaft 5.2 is perpendicular to the wheel plate surface of the cam block 5.1, the axis of the drive shaft 5.2 is parallel to the horizontal plane, the axis of the drive shaft 5.2 is perpendicular to the axis of the connecting column 4.2, both ends of the drive shaft 5.2 are movably mounted with support ear plates fixed to the upper plate body 1, and a long strip opening for the force arm 5.3 to pass through is opened on the plate body of the upper plate body 1;

[0033] In actual use, after the connecting pipe 6 is vertically arranged in the interval space formed in the vertical direction between the upper plate body 1 and the lower plate body 2, the driving shaft 5.2 is rotated by deflecting the force arm rod 5.3. At this time, the cam block 5.1 fixed to the driving shaft 5.2 is synchronously deflected at the force-bearing opening 4.3, and the other protruding part of the cam block 5.1 moves toward the inner top direction of the force-bearing opening 4.3, so that the connecting column 4.2 drives the lower plate body 2 to move toward the upper plate body 1, thereby reducing the interval space and allowing the connecting pipe 6 to be clamped and fixed. The whole process is simple to operate and the locking is stable, which is conducive to reducing the number of bolts, and is also convenient for disassembly and maintenance, simplifies the operation steps and reduces the difficulty of disassembly and assembly. The structure is simple and stable, and it is also conducive to overcoming the problems of rusted bolts and inability to disassemble, and has good practical significance.

[0034] In another embodiment provided by the present invention, the pipe joint structure 3 includes plug-in ports 3.1 respectively located on the upper plate body 1 and the lower plate body 2, the plug-in ports 3.1 are located on the side of the upper plate body 1 facing the partition space, and a step groove 3.2 is provided on the inner wall of each plug-in port 3.1, the step groove 3.2 is an annular groove, and a bridge conduction unit 3.3 adapted to the end of the connecting pipe 6 is provided in the step groove 3.2;

[0035] The bridge conduction unit 3.3 includes a conduction tube 3.31, the inner wall surface of the conduction tube 3.31 is composed of a first inner diameter portion 3.32, a second inner diameter portion 3.33 and a third inner diameter portion 3.34 which are continuously distributed, the inner wall surface of the second inner diameter portion 3.33 is a conical surface, and the inner wall surface of the second inner diameter portion 3.33 is connected to the outer wall surface of the end of the connecting tube 6 through a threaded structure 3.35;

[0036] Furthermore, a plurality of evenly distributed card slots 3.21 are provided on the side wall of the step slot 3.2, one end of the card slot 3.21 is an open end, and each card slot 3.21 is adapted to be carded with a card block 3.22 connected to the outer wall of the second inner diameter portion 3.33;

[0037] Specifically, the thread structure 3.35 includes a screw tooth structure 3.351 located on the inner wall of the second inner diameter portion 3.33 and a spiral structure 3.352 located on the outer end of the connecting pipe 6, the spiral structure 3.352 is a conical spiral structure, and the conical surface degree of the conical spiral structure is the same as the conical surface degree of the inner wall of the second inner diameter portion 3.33, the screw tooth structure 3.351 includes a plug hole 3.3511 opened on the inner wall of the second inner diameter portion 3.33, the screw tooth structure 3.351 also includes a block 3.22 movably passing through the plug hole 3.3511, the plug hole 3.3511 and the block 3.22 constitute a screw tooth structure 3.351 that can be plugged and matched with the spiral structure 3.352, and one end of the block 3.22 extending into the second inner diameter portion 3.33 can be spirally meshed and slid with the spiral structure 3.352;

[0038] In actual use, the connecting tube 6 is plugged into the conducting tube 3.31 in the plug port 3.1, and then the connecting tube 6 is rotated clockwise. At this time, the spiral structure 3.352 rotates synchronously with the connecting tube 6. Since the screw tooth structure 3.351 is composed of the plug hole 3.3511 and the clamping block 3.22, one end of the clamping block 3.22 slides relatively along the spiral line of the spiral structure 3.352. Since the spiral structure 3.352 is a conical spiral structure, as the depth of the spiral insertion of the connecting tube 6 increases, the spiral structure 3.352 slides relatively along the spiral line of the spiral structure 3.352. As the screw structure 3.352 is further deepened, the diameter value of the position where the spiral structure 3.352 contacts the block 3.22 is further increased, so that the block 3.22 is squeezed and moves toward the slot 3.21, thereby further increasing the engagement depth between the block 3.22 and the slot 3.21. When the connecting tube 6 reaches the maximum spiral position, the connecting tube 6 cannot continue to rotate clockwise. At this time, the connecting tube 6 completes the preliminary connection with the conducting tube 3.31, and the tube body of the connecting tube 6 is located in the plug interface 3.1 to form a plug-in state.

[0039] In another embodiment provided by the present invention, an elastic sealing gasket 3.4 is provided between the bottom wall of the step groove 3.2 and the outside of the conducting tube 3.31, thereby increasing the sealing between the connecting tube 6 and the step groove 3.2. When an extrusion force occurs between the connecting tube 6 and the step groove 3.2, the elastic sealing gasket 3.4 undergoes elastic deformation to fill and seal the connecting gap.

[0040] In another embodiment provided by the present invention, the state of the lever arm 5.3 when in the pressed position is that the lever body is inclined at an acute angle to the horizontal plane, and the bottom end of the lever body of the lever arm 5.3 when in the pressed position can be locked and limited with the bottom end of the lever arm 5.3 adjacent to the mirror image;

[0041] Specifically, when the lever arm 5.3 is in the pressed position, the rod body of the lever arm 5.3 is located in the spacing space formed vertically between the upper plate body 1 and the lower plate body 2. For example, the angle between the rod body of the lever arm 5.3 and the horizontal plane is 45 degrees, and the angle between the mirror-adjacent lever arm 5.3 and the horizontal plane is also 45 degrees. The bottom ends of the two mirror-symmetrically distributed lever arm 5.3 are in contact with each other, thereby preventing the lever arm 5.3 from resetting and deflecting toward the unloading position, so that the two mirror-oppositely distributed lever arm 5.3 form a mutual locking limit at the pressed position, without the need to additionally set up a corresponding locking limit mechanism.

[0042] In another embodiment provided by the present invention, a sleeve 6.1 is slidably sleeved on the tube body of the connecting tube 6, protruding rods 6.2 are fixed on both sides of the sleeve 6.1, the rod body axis of the protruding rod 6.2 is perpendicular to the axis of the sleeve 6.1, the lever arm 5.3 can contact one of the protruding rods 6.2 when in the pressed position, and the component of the force of the lever arm 5.3 on the protruding rod 6.2 is the same as the force of the connecting tube 6 in the screwing direction on the bridge conduction unit 3.3;

[0043] It should be particularly noted that one end of the rod body of the protruding rod 6.2 fixed to the sleeve 6.1 extends into the sleeve 6.1, and a plurality of reinforcing ribs 6.3 are fixed to the tube body of the connecting tube 6, and a rib-groove structure is formed between the reinforcing ribs 6.3, and the length direction line of the groove body of the rib-groove structure is parallel to the axis line of the connecting tube 6, and one end of the protruding rod 6.2 can slide along the groove body of the rib-groove structure, thereby limiting the axial rotation of the sleeve 6.1 on the connecting tube 6;

[0044] Specifically, the two lever arms 5.3 are rotationally symmetrically distributed about the connecting tube 6. When the lever arms 5.3 are in the pressed position, the protruding rods 6.2 on both sides of the sleeve 6.1 contact the corresponding lower side parts of the lever arms 5.3. Since the lever arms 5.3 have a tendency to deflect toward the unloading position in the pressed position, the lever arms 5.3 generate a rotary force on the sleeve 6.1 through the protruding rods 6.2. The direction of the rotary force is the same as the clockwise rotation direction of the connecting tube 6, which is conducive to the screwing and tightening of the connecting tube 6 on the conducting tube 3.31, and prevents the screwing of the connecting tube 6 from loosening.

[0045] In another embodiment provided by the present invention, the lever arm 5.3 comprises a lever arm tube 5.31 fixed to the driving shaft 5.2, an extension rod 5.32 capable of contacting the protruding rod 6.2 is movably inserted inside the lever arm tube 5.31, and one end of the lever arm tube 5.31 away from the extension rod 5.32 is a blocking end, and further, a stopper 5.33 capable of blocking the lever arm tube 5.31 is fixed to one end of the extension rod 5.32 inserted into the lever arm tube 5.31, a stopper ring 5.34 fixed to the inner wall of the lever arm tube 5.31 is movably sleeved outside the extension rod 5.32, a first notch 5.35 is provided on the stopper ring 5.33, and a second notch 5.36 is provided on the stopper ring 5.34;

[0046] In actual use, when the retaining ring 5.34 contacts the stopper 5.33, the extension rod 5.32 is in an extended state. At the same time, the tube space between the stopper 5.33 and the blocking end of the arm tube 5.31 is filled with hard particles, such as sand or stainless steel particles, which have a certain fluidity. When the extension rod 5.32 is in an extended state, the extension rod 5.32 is axially rotated to stagger the first notch 5.35 and the second notch 5.36. The hard particles in the tube space also prevent the extension rod 5.32 from contracting in the arm tube 5.31. When disassembly is to be carried out, the extension rod 5.32 is axially rotated so that the first notch 5.35 is aligned with the second notch 5.36, thereby releasing the hard particles in the tube space, and then the extension rod 5.32 is contracted toward the lever arm tube 5.31 and disengaged from the protruding rod 6.2, so that the protruding rod 6.2 no longer limits and locks the lever arm rod 5.3. At this time, the lever arm rod 5.3 can be deflected from the pressed position to the unloading position, the distance between the upper plate body 1 and the lower plate body 2 can be opened, and the connecting tube 6 can be disassembled from between the upper plate body 1 and the lower plate body 2. The whole process is simple and convenient to operate.

[0047] In another embodiment of the present invention, the above-mentioned multi-stage mixed pump housing connection structure is provided on the mixed pump, and an interval space capable of being clamped is formed by utilizing the upper plate body 1 and the lower plate body 2, and the spacing size of the interval space is controlled by the clamping and locking mechanism, so that the connecting pipe 6 and even the submersible motor located in the interval space are clamped and fixed. Compared with the traditional method of using a large number of bolts as fasteners, the number of bolts is reduced, the operation is simpler and more convenient, the locking is stable, the influence of rust on the fasteners is reduced, and the degree of assembly integration is improved. On the other hand, the clamping and locking mechanism is mainly composed of an interlaced component and a force-applying component. Before the connecting pipe 6 is subjected to the clamping force, the connecting pipe 6 can form a preliminary connection in the interval space, that is, the connecting pipe 6 is connected with the pipeline on the machine pump frame and the pipeline structure on the motor frame through the pipe joint structure 3 to form a preliminary connection of the diversion channel; when clamped and fixed, the connecting pipe 6 forms a clamped and fixed limit in the interval space, and the clamping and locking mechanism can achieve an automatic locking and limiting effect, and the force arm rod 5.3 on the clamping and locking mechanism also prevents the connecting pipe 6 from loosening when it is rotated. The various component parts of the clamping and locking mechanism can cooperate with each other in the locked state to further improve the stability of the locking.

[0048] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A multi-stage mixed pump casing connection structure, comprising an upper plate (1) fixed to a pump frame and a lower plate (2) fixed to a motor frame, and also comprising a connecting pipe (6), characterized in that: The upper plate body (1) and the lower plate body (2) are both provided with a pipe joint structure (3) adapted to be plugged into the connecting pipe (6), and the upper plate body (1) and the lower plate body (2) are connected via a clamping and locking mechanism, and the clamping and locking mechanism comprises: An insertion assembly (4) comprising two installation openings (4.1) symmetrically opened on the upper plate body (1), each installation opening (4.1) having a connecting column (4.2) fixed to the lower plate body (2) movably penetrated therein, and a force receiving opening (4.3) is provided on the connecting column (4.2); A force-applying assembly (5) comprises a cam block (5.1) located in a force-receiving opening (4.3); a driving shaft (5.2) rotatably connected to an upper plate body (1) is fixedly passed through a side surface of the cam block (5.1); lever arms (5.3) connected to the driving shaft (5.2) are symmetrically arranged on both sides of the connecting column (4.2); the lever arms (5.3) have a pressing position and a releasing position in their movement stroke; when the lever arms (5.3) are in the pressing position, an extrusion state is formed between the upper plate body (1) and the lower plate body (2) to apply pressure to the end of the connecting pipe (6).

2. A multi-stage mixed flow pump casing connection structure according to claim 1, characterized in that: The pipe joint structure (3) comprises plug-in ports (3.1) respectively located on the upper plate body (1) and the lower plate body (2), each of the plug-in ports (3.1) having a stepped groove (3.2) formed on its inner wall, and a bridging conduction unit (3.3) adapted to the end of the connecting pipe (6) being provided in the stepped groove (3.2).

3. A multi-stage mixed flow pump casing connection structure according to claim 2, characterized in that: The bridge conduction unit (3.3) comprises a conduction tube (3.31), the inner wall surface of the conduction tube (3.31) being composed of a first inner diameter portion (3.32), a second inner diameter portion (3.33) and a third inner diameter portion (3.34) which are continuously distributed, the inner wall of the second inner diameter portion (3.33) being a conical surface, and the inner wall surface of the second inner diameter portion (3.33) being connected to the outer wall surface of the end of the connecting tube (6) via a threaded structure (3.35).

4. A multi-stage mixed flow pump casing connection structure according to claim 3, characterized in that: A plurality of evenly distributed clamping grooves (3.21) are provided on the groove side wall surface of the step groove (3.2), and each of the clamping grooves (3.21) is adapted to be clamped with a clamping block (3.22) connected to the outer wall surface of the second inner diameter portion (3.33).

5. A multi-stage mixed flow pump casing connection structure according to claim 4, characterized in that: The thread structure (3.35) comprises a screw tooth structure (3.351) located on the inner wall of the second inner diameter portion (3.33) and a spiral structure (3.352) located on the outer end of the connecting pipe (6); the spiral structure (3.352) is a conical spiral structure; the screw tooth structure (3.351) comprises a plug hole (3.3511) opened on the inner wall of the second inner diameter portion (3.33); the screw tooth structure (3.351) further comprises a clamping block (3.22) movably passing through the plug hole (3.3511); an end of the clamping block (3.22) extending into the second inner diameter portion (3.33) is capable of spirally meshing and sliding with the spiral structure (3.352).

6. A multi-stage mixed flow pump casing connection structure according to claim 5, characterized in that: An elastic sealing gasket (3.4) is provided between the bottom wall of the step groove (3.2) and the outside of the conducting pipe (3.31).

7. A multi-stage mixed flow pump casing connection structure according to claim 6, characterized in that: When the lever arm (5.3) is in the pressed position, the lever body is in an inclined state with an acute angle to the horizontal plane, and the bottom end of the lever body of the lever arm (5.3) in the pressed position can be locked and limited with the bottom end of the lever arm (5.3) adjacent to the mirror image.

8. The multi-stage mixed flow pump casing connection structure according to claim 7, characterized in that: A sleeve (6.1) is slidably sleeved on the tube body of the connecting tube (6), protruding rods (6.2) are fixed on both sides of the sleeve (6.1), and the force arm rod (5.3) can contact one of the protruding rods (6.2) when in the pressed position, and the component of the force of the force arm rod (5.3) on the protruding rod (6.2) is the same as the force of the connecting tube (6) in the screwing direction on the bridge conduction unit (3.3).

9. A multi-stage mixed flow pump casing connection structure according to claim 8, characterized in that: The lever arm (5.3) comprises a lever arm tube (5.31) fixed to the drive shaft (5.2), and an extension rod (5.32) capable of contacting the protruding rod (6.2) is movably inserted into the interior of the lever arm tube (5.31).

10. A mixed flow pump, characterized in that: The mixed flow pump is provided with a multi-stage mixed flow pump housing connection structure as described in any one of claims 1 to 9.

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