Multi-stage liquid centrifugal pump with eccentric deflection of middle-section rotor

Abstract

The utility model relates to a multistage liquid centrifugal pump, in particular to a multistage liquid centrifugal pump with eccentric deflection of a middle-section rotor. A pump cover (2) in front of the pump is fixedly connected with a barrel (1); the first-stage middle section (4) and the cylinder body (1) are positioned by adopting a spigot; the radial positioning seam allowances of the first-stage middle section (4) and the second-stage middle section (5) are eccentric, the radial positioning seam allowances of the second-stage middle section (5), the third-stage middle section (6) and the fourth-stage middle section (7) are concentric, the radial positioning seam allowances of the fourth-stage middle section (7) and the fifth-stage middle section (8) are eccentric, the radial positioning seam allowances of the fifth-stage middle section (8) and the sixth-stage middle section (9) are eccentric, and the radial positioning seam allowances of the sixth-stage middle section (9) and the barrel body (1) are concentric; and the cylinder body (1) is fixedly connected with the rear pump cover (3). According to the utility model, contact friction and shaft sticking between the rotor and static parts during starting, shutdown and operation, especially during low-rotating-speed turning are avoided. The service life of parts is prolonged, gaps between dynamic / static parts are minimized, and the efficiency of the pump is improved.

Description

Technical Field

[0001] The utility model relates to a multistage liquid centrifugal pump, in particular to a multistage liquid centrifugal pump with eccentric deflection of the middle-stage rotor. Background Art

[0002] A multistage centrifugal pump is a centrifugal pump capable of transporting high-pressure liquids. It is suitable for transporting liquids and media with high head and high pressure, and is widely used in various industries, such as the petroleum, chemical, and power generation industries.

[0003] The multistage centrifugal pump sucks the liquid from the suction port through the centrifugal force of the impeller, and after continuous pressurization and guidance by multiple impellers, it is finally discharged from the discharge port. Since it is a small flow rate and high head composed of two or more impellers, the length of the shaft is very long, so the deflection of the shaft increases. At the same time, if the shaft deflection is too large, it will cause premature failure of the wear-resistant ring, mechanical seal and bearing. The deflection of the shaft caused by the radial force will generate a bending force, and this bending dynamic will generate shaft tensile bending fatigue, which is prone to cause the hazard of shaft breakage and cannot meet the long-term uninterrupted operation. To solve this problem, it is necessary to develop an improvement on the existing multistage centrifugal pump. Summary of the Invention

[0004] The purpose of the utility model is to provide a multistage liquid centrifugal pump with eccentric deflection of the middle-stage rotor. The middle-stage component of the utility model is designed into an eccentric positioning structure according to the deflection of the rotor, so as to avoid the contact friction and shaft seizure between the rotor and the stationary parts during startup, shutdown and operation, especially during low-speed barring. It is applicable to the working conditions of frequent start and stop, which can greatly improve the service life of the parts, minimize the clearance between the moving and static parts, and improve the efficiency of the pump.

[0005] The purpose of the utility model is realized by the following technical solutions:

[0006] A multistage liquid centrifugal pump with eccentric deflection of the middle-stage rotor, the centrifugal pump includes a housing assembly, a middle-stage assembly, a rotor assembly, and a bearing body component; the front pump cover and the cylinder are connected and fixed by bolts and nuts, and are sealed by a spiral wound gasket; the first-stage middle-stage and the cylinder are positioned by a spigot and sealed by a spiral wound gasket; the radial positioning spigots between the first-stage middle-stage and the second-stage middle-stage are eccentric, the radial positioning spigots between the second-stage middle-stage and the third-stage middle-stage, and the fourth-stage middle-stage are concentric, the radial positioning spigots between the fourth-stage middle-stage and the fifth-stage middle-stage are eccentric, the radial positioning spigots between the fifth-stage middle-stage and the sixth-stage middle-stage are eccentric, the radial positioning spigot between the sixth-stage middle-stage and the cylinder is concentric, the cylinder 1 and the rear pump cover are connected and fixed by bolts and nuts, and are sealed by a spiral wound gasket, the guide vane is arranged in the middle of each stage of the middle-stage, and an anti-rotation positioning pin is installed between each stage, which forms a core-pullable pump core with the rotor assembly.

[0007] The described multi-stage liquid centrifugal pump with eccentric deflection of the middle-stage rotor, the housing assembly includes a cylinder, a front pump cover, and a rear pump cover.

[0008] The described multi-stage liquid centrifugal pump with eccentric deflection of the middle-stage rotor, the middle-stage assembly includes a first-stage middle section, a second-stage middle section, a third-stage middle section, a fourth-stage middle section, a fifth-stage middle section, a sixth-stage middle section, and a diffuser.

[0009] The described multi-stage liquid centrifugal pump with eccentric deflection of the middle-stage rotor, the rotor assembly consists of an impeller and a shaft.

[0010] The described multi-stage liquid centrifugal pump with eccentric deflection of the middle-stage rotor, the bearing body component includes a radial bearing component and a thrust bearing component.

[0011] The advantages and effects of the present utility model are:

[0012] The middle-stage assembly of the present utility model is designed into an eccentric positioning structure according to the deflection of the rotor, avoiding contact friction and shaft seizure between the rotor and stationary components during startup, shutdown, and operation (especially during low-speed barring). Especially for working conditions with frequent starts and stops, it can greatly improve the service life of components. The clearance between moving and stationary components can be minimized, improving the efficiency of the pump. Description of the Drawings

[0013] Figure 1 It is a structural diagram of a multi-stage centrifugal pump with an eccentric middle-stage assembly structure of the present utility model;

[0014] Figure 2 It is a schematic diagram of the eccentric difference state between the center of the upper half and the center of the lower half of the middle-stage assembly of the present utility model;

[0015] Figure 3 It is of the present utility model Figure 2 Axial three-dimensional enlarged schematic diagram;

[0016] Figure 4 It is a three-dimensional schematic diagram of the rotor of the present utility model. Detailed Description of the Preferred Embodiment

[0017] The present utility model will be described in detail below with reference to the embodiments shown in the drawings.

[0018] Figure 1 As shown, a multi-stage centrifugal pump with an eccentric middle-stage assembly structure includes a cylinder 1, a front pump cover 2, a rear pump cover 3, a first-stage middle section 4, a second-stage middle section 5, a third-stage middle section 6, a fourth-stage middle section 7, a fifth-stage middle section 8, a sixth-stage middle section 9, a diffuser 10, an impeller 11, a shaft 12, a radial bearing component 13, and a thrust bearing component 4.

[0019] The front pump cover 2 and the cylinder body 1 are connected and fixed by bolts and nuts, and are sealed by a spiral wound gasket in between; the first-stage middle section 4 and the cylinder body 1 are positioned by a spigot and sealed by a spiral wound gasket; the radial positioning spigot between the first-stage middle section 4 and the second-stage middle section 5 is an eccentric dimension, the radial positioning spigots between the second-stage middle section 5 and the third-stage middle section 6, and the fourth-stage middle section 7 are concentric dimensions, the radial positioning spigot between the fourth-stage middle section 7 and the fifth-stage middle section 8 is an eccentric dimension, the radial positioning spigot between the fifth-stage middle section 8 and the sixth-stage middle section 9 is an eccentric dimension, the radial positioning spigot between the sixth-stage middle section 9 and the cylinder body 1 is a concentric dimension, the cylinder body 1 and the rear pump cover 3 are connected and fixed by bolts and nuts, and are sealed by a spiral wound gasket in between. The guide vane 10 is installed in the middle of each stage middle section, and anti-rotation positioning pins are installed between each stage. It forms a core-pullable pump core with the rotor assembly.

[0020] Its impeller 11 is slid onto the shaft 12 in sequence; it forms a rotor assembly.

[0021] The rotor assembly is radially supported and axially fixed by two radial bearing body components 13 and a thrust bearing component 14.

[0022] According to the deflection distribution of the shaft (see Figure 1 ), the middle section assembly is designed. The first-stage middle section 4 and the cylinder body 1 are positioned by a spigot and sealed by a spiral wound gasket; then the impeller 11 is slid onto the shaft 12, and after installation, it is inserted into the first-stage middle section 4 as a whole. The guide vane 10 is installed between the first-stage middle section 4 and the second-stage middle section 5. The radial positioning spigot between the first-stage middle section 4 and the second-stage middle section 5 is an eccentric dimension, the radial positioning spigots between the second-stage middle section 5 and the third-stage middle section 6, and the fourth-stage middle section 7 are concentric dimensions, the radial positioning spigot between the fourth-stage middle section 7 and the fifth-stage middle section 8 is an eccentric dimension, the radial positioning spigot between the fifth-stage middle section 8 and the sixth-stage middle section 9 is an eccentric dimension, the radial positioning spigot between the sixth-stage middle section 9 and the cylinder body 1 is a concentric dimension, the cylinder body 1 and the rear pump cover 3 are connected and fixed by bolts and nuts, and are sealed by a spiral wound gasket in between. The impeller 11 and the guide vane 10 are installed in the middle of each stage middle section, and anti-rotation positioning pins are installed between each stage. The middle section assembly and the rotor assembly form a core-pullable pump core. The pump core is installed in the housing assembly, and the radial bearing body components 13 and the thrust bearing component 14 are installed at both ends to complete radial support and axial fixation.

[0023] For the cylinder body of the present utility model, the radial positioning spigot with the first-stage middle section is a concentric dimension, the radial positioning spigot between the first-stage middle section and the second-stage middle section is an eccentric dimension, the radial positioning spigots between the second-stage middle section and the third- and fourth-stage middle sections are concentric dimensions, the radial positioning spigot between the fourth-stage middle section and the fifth-stage middle section is an eccentric dimension, the radial positioning spigot between the fifth-stage middle section and the sixth-stage middle section is an eccentric dimension, and the radial positioning spigot between the sixth-stage middle section and the cylinder body is a concentric dimension.

Claims

1. A multi-stage liquid centrifugal pump with an eccentric middle rotor deflection, characterized in that: The centrifugal pump comprises a casing assembly, a middle section assembly, a rotor assembly, and a bearing body component; the front pump cover (2) and the cylinder (1) are connected and fixed by bolts and nuts, and are sealed by a spiral wound gasket; the first-stage middle section (4) and the cylinder (1) are positioned by a stopper, and are sealed by a spiral wound gasket; the radial positioning stopper of the first-stage middle section (4) and the second-stage middle section (5) is eccentric, and the radial positioning stopper of the second-stage middle section (5) and the third-stage middle section (6) and the fourth-stage middle section (7) is concentric. The radial positioning stoppers of the fourth-stage middle section (7) and the fifth-stage middle section (8) are eccentric, the radial positioning stoppers of the fifth-stage middle section (8) and the sixth-stage middle section (9) are eccentric, and the radial positioning stoppers of the sixth-stage middle section (9) and the barrel (1) are concentric. The barrel (1) and the rear pump cover (3) are connected and fixed by bolts and nuts, and are sealed by a wound gasket. The guide vane (10) is arranged in the middle of each stage of the middle section, and an anti-rotation positioning pin is installed between each stage to form a core-removable pump core with the rotor assembly.

2. A multi-stage liquid centrifugal pump with an eccentric middle rotor deflection according to claim 1, characterized in that: The housing assembly comprises a cylinder (1), a front pump cover (2), and a rear pump cover (3).

3. A multi-stage liquid centrifugal pump with eccentric middle rotor deflection according to claim 1, characterized in that: The midsection assembly comprises a first-stage midsection (4), a second-stage midsection (5), a third-stage midsection (6), a fourth-stage midsection (7), a fifth-stage midsection (8), a sixth-stage midsection (9) and guide vanes (10).

4. A multi-stage liquid centrifugal pump with eccentric middle rotor deflection according to claim 1, characterized in that: The rotor assembly consists of an impeller (11) and a shaft (12).

5. A multi-stage liquid centrifugal pump with eccentric middle rotor deflection according to claim 1, characterized in that: The bearing body component comprises a radial bearing component (13) and a thrust bearing component (14).

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