Shield pump with back blade structure

Abstract

The utility model discloses a shield pump with a back blade structure, which belongs to the field of shield pumps and comprises a pump body, the rear end of the pump body is fixedly connected with a motor casing, a rotor component and a stator component are arranged in the motor casing, the front end of the rotor component extends into the pump body, an impeller is fixedly mounted at the tail end of the rotor component, and the stator component is fixedly connected with the motor casing. A plurality of back blades are arranged on the back face of the impeller in the radial direction. A balance boss structure arranged on the cover plate and a large opening ring structure on the back face of the impeller are omitted, meanwhile, a plurality of back blades are arranged on the back face of the impeller in the radial direction, axial force is counteracted through reverse thrust generated when the back blades of the impeller rotate, and therefore balance is achieved; the structure is free of sensitive gaps and resistant to abrasion or corrosion, axial force balance cannot be damaged even if corrosive media are conveyed and the back blades are slightly abraded or corroded, and therefore long-period stable operation of the pump is achieved.

Description

Technical Field

[0001] The utility model relates to the field of canned pumps, in particular to a canned pump with a back vane structure. Background Technique

[0002] A canned pump is a combination of a centrifugal pump and a canned motor. The rotor of the canned motor and the impeller of the centrifugal pump are fixed on the same shaft. The rotor and the stator are separated by a shield sleeve. The rotor rotates in the medium to be transported, and its power is transmitted to the rotor through the stator magnetic field and then to the impeller. There is no dynamic seal in the structure of the canned pump, which can completely achieve zero leakage. It is widely used in transporting flammable, explosive, volatile, toxic, corrosive and precious media, and is an important fluid transportation equipment in the fields of chemical industry, petrochemical industry, chemical fiber, pharmaceutical, refrigeration, etc.

[0003] Axial force refers to the force generated along the axial direction during the operation of the pump, which is inevitable. Its magnitude and direction depend on the design and working conditions of the pump. If the axial force is too large, it will cause excessive loads on the bearings and seals of the pump, thus affecting the life and stability of the pump. In addition, the axial force will also affect the flow rate and head of the pump, thus affecting the working efficiency of the pump.

[0004] Most of the canned pumps on the market have a structure of "large mouth ring + balance hole". It has a balance boss and a large mouth ring to form a balance chamber. For example, in the utility model patent "A canned pump with an axial force balance auxiliary device" with the patent application number 201721362556.0, it discloses that the rear surface of the rear cover plate 32 of the impeller is provided with a protruding back mouth ring 323. Since both the balance boss and the large mouth ring are sensitive gaps, the throttling effect of the gap of the large mouth ring on the back of the impeller on the axial force is very sensitive. If it is corroded or worn, resulting in an enlarged gap, the axial force balance will be destroyed and the pump cannot operate stably. Therefore, this structure is suitable for media with no corrosion or extremely low corrosion. Content of the Utility Model

[0005] The main purpose of the utility model is to provide a canned pump with a back vane structure, which can effectively solve the problems mentioned in the background technique.

[0006] To achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0007] A canned pump with a back vane structure includes a pump body. A motor housing is fixedly connected to the rear end of the pump body, and a rotor assembly and a stator assembly are arranged in the motor housing. The front end of the rotor assembly extends into the pump body, and an impeller is fixedly installed at the end. A plurality of back vanes are arranged radially along the back of the impeller.

[0008] Preferably, the rotor assembly is disposed at the center of the stator assembly, and a rotor shielding sleeve is provided outside the rotor assembly to wrap the rotor assembly. A stator shielding sleeve is provided on the inner wall of the stator assembly to separate the stator assembly. The rotor shielding sleeve and the stator shielding sleeve form a sealed isolation structure.

[0009] Preferably, front bearing bodies and rear bearing bodies are respectively installed at the head and tail ends of the motor housing. Front bearing groups and rear bearing groups are respectively assembled at the central positions of the front bearing bodies and the rear bearing bodies. Both ends of the rotor assembly are respectively rotationally connected to the front bearing bodies and the rear bearing bodies through the front bearing groups and the rear bearing groups. An auxiliary impeller is also installed in front of the rear bearing group at the tail of the rotor assembly.

[0010] Preferably, a shaft sleeve is installed at the front part of the rotor assembly, and an impeller is fixedly installed at the front end.

[0011] Preferably, a cover plate is fixedly installed at the front end of the front bearing body, and the cover plate is located behind the impeller.

[0012] Compared with the prior art, the present utility model has the following beneficial effects:

[0013] In the present utility model, by canceling the balance boss structure provided on the cover plate and the large orifice ring structure on the back of the impeller, and at the same time, a plurality of back vanes are radially provided on the back of the impeller. The reaction force generated when the back vanes rotate is used to offset the axial force, thereby achieving balance. And such a structure has no sensitive gap, is not afraid of wear or corrosion. Even if the back vanes are slightly worn or corroded, the axial force balance will not be damaged, thus realizing the long-term stable operation of the pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a sectional view of the overall structure of the present utility model;

[0015] Figure 2 is a schematic diagram of the medium circulation inside the pump of the present utility model;

[0016] Figure 3 is a schematic diagram of the structure of the back vanes of the present utility model.

[0017] In the figure: 1, pump body; 2, impeller; 3, cover plate; 4, shaft sleeve; 5, front bearing body; 6, rear bearing body; 7, front bearing group; 8, rear bearing group; 9, rotor assembly; 10, stator assembly; 11, rotor shielding sleeve; 12, stator shielding sleeve; 13, auxiliary impeller; 14, back vanes; 15, motor housing. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] To make the technical means, creative features, achieved purposes and effects realized by the present utility model easy to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0019] As Figure 1 shown, a canned motor pump with a back vane structure includes a pump body 1. A motor housing 15 is fixedly connected to the rear end of the pump body 1. A rotor assembly 9 and a stator assembly 10 are provided in the motor housing 15. The rotor assembly 9 is arranged at the center of the stator assembly 10. A rotor shield 11 is provided outside the rotor assembly 9 to wrap the rotor assembly 9. A stator shield 12 is provided on the inner wall of the stator assembly 10 to separate the stator assembly 10. The rotor shield 11 and the stator shield 12 form a sealed isolation structure. A front bearing housing 5 and a rear bearing housing 6 are respectively installed at the head and tail ends of the motor housing 15. A front bearing set 7 and a rear bearing set 8 are respectively assembled at the central positions of the front bearing housing 5 and the rear bearing housing 6. The two ends of the rotor assembly 9 are respectively rotatably connected to the front bearing housing 5 and the rear bearing housing 6 through the front bearing set 7 and the rear bearing set 8. An auxiliary impeller 13 is also installed at the rear of the rotor assembly 9 in front of the rear bearing set 8. A shaft sleeve 4 is installed at the front of the rotor assembly 9, and an impeller 2 is fixedly installed at the front end. A cover plate 3 is fixedly installed at the front end of the front bearing housing 5, and the cover plate 3 is located behind the impeller 2.

[0020] As Figure 3 shown, a plurality of back vanes 14 are provided radially on the back of the impeller 2, and the balance boss and large mouth ring structure in the traditional technology are cancelled. The axial force is offset by the reverse thrust when the back vanes 14 on the impeller 2 rotate, so as to achieve balance.

[0021] As Figure 2As shown, in actual work, the rotor assembly 9 inside the motor housing 15 is coaxial with the impeller 2 of the pump. The rotor assembly 9 and the stator assembly 10 of the motor are isolated by the rotor shielding sleeve 11 and the stator shielding sleeve 12. The rotor assembly 9 is supported by front and rear sliding bearings and immersed in the conveying medium. During operation, the motor stator assembly 10 drives the rotor assembly 9 to rotate, and at the same time drives the impeller 2 to rotate, enabling the impeller 2 to do work on the medium to achieve the conveyance of the medium. The medium enters the pump body 1 through the pump inlet. After being pressurized by the impeller 2, most of the medium flows out from the outlet of the pump body 1. At the outlet of the impeller 2, a part of the medium is diverted and enters the central hole of the rotor assembly 9 through the circulation holes on the front bearing body 5 and the shaft sleeve 4, flows backward, and after being pressurized twice by the auxiliary impeller 13, flows forward through the gap between the rotor shielding sleeve 11 and the stator shielding sleeve 12, flows through the circulation holes of the front bearing body 5 and the cover plate 3, and enters the gap between the back blades 14 on the back of the impeller 2 and the cover plate 3. After being pressurized by the back blades 14, it merges into the main pump outlet circulation and flows out from the outlet of the pump body 1. This diverted medium can lubricate the front bearing group 7 and the rear bearing group 8, and can take away the heat generated during the operation of the motor. Because it is pressurized twice by the auxiliary impeller 13, this diverted medium is always in a high-pressure state, preventing vaporization phenomenon caused by the temperature rise of the motor heat being taken away.

[0022] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A canned motor pump with a back blade structure, comprising a pump body (1), characterized in that: The rear end of the pump body (1) is fixedly connected to a motor housing (15), and a rotor assembly (9) and a stator assembly (10) are arranged in the motor housing (15). The front end of the rotor assembly (9) extends into the pump body (1), and an impeller (2) is fixedly installed at the end. The back of the impeller (2) is radially provided with a plurality of back blades (14).

2. A back-vane structure canned motor pump according to claim 1, characterized in that: The rotor assembly (9) is arranged at the center of the stator assembly (10), and a rotor shielding sleeve (11) is provided on the outside of the rotor assembly (9) to wrap the rotor assembly (9), and a stator shielding sleeve (12) is provided on the inner wall of the stator assembly (10) to separate the stator assembly (10), and the rotor shielding sleeve (11) and the stator shielding sleeve (12) form a sealed isolation structure.

3. A back-vane structure canned motor pump according to claim 2, characterized in that: The front and rear ends of the motor housing (15) are respectively mounted with a front bearing body (5) and a rear bearing body (6); the center positions of the front and rear bearing bodies (5 and 6) are respectively mounted with a front bearing group (7) and a rear bearing group (8); the two ends of the rotor assembly (9) are respectively rotatably connected to the front bearing body (5) and the rear bearing body (6) via the front bearing group (7) and the rear bearing group (8); and an auxiliary impeller (13) is also mounted at the rear of the rotor assembly (9) in front of the rear bearing group (8).

4. A back-vane structure canned motor pump according to claim 3, characterized in that: A shaft sleeve (4) is installed at the front of the rotor assembly (9), and an impeller (2) is fixedly installed at the front end.

5. A back-vane structure canned motor pump according to claim 4, characterized in that: A cover plate (3) is fixedly mounted on the front end of the front bearing body (5), and the cover plate (3) is located behind the impeller (2).

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