CN112524041A

CN112524041A - Centrifugal pump with pair rotor structure

Info

Publication number: CN112524041A
Application number: CN202011334906.9A
Authority: CN
Inventors: 高波; 顾嘉嵘; 张宁; 倪丹
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2020-11-25
Filing date: 2020-11-25
Publication date: 2021-03-19

Abstract

The invention relates to a centrifugal pump with a rotor structure, and belongs to the field of fluid machinery. The invention realizes that the two impellers rotate in opposite rotation directions by independently adjusting the rotation speeds of the front impeller and the rear impeller through the two motors, widens the operating condition range of the pump, enhances the adaptability to variable working conditions, and provides more adjustable parameters for intelligent control. Compared with the traditional design with the same parameters, the back impeller can obviously improve the power density by doing work again on the fluid, the negative prerotation energy of the inlet of the back impeller can reduce the outer diameter of the impeller, the linear speed of the impeller is reduced, and the vibration reduction and the noise reduction are facilitated.

Description

Centrifugal pump with pair rotor structure

Technical Field

The invention relates to a centrifugal pump with a rotor structure, and belongs to the field of fluid machinery.

Background

The pump is used as a general machine, plays an important role in the fields of petrifaction, energy, electric power, national defense, military and the like, has high parameter performance, has a special, extreme and intelligent development trend in operation, and is generally developed towards the directions of high power density, low vibration noise, multi-working-condition operation and the like. High speed is the simplest and most effective way to increase the power density of the pump, but is limited by cavitation, intensity and vibration noise, and has limited potential; the multi-stage impeller design can reduce the linear speed of the impeller, and is applied, but the axial size of the pump is increased. The limited regulation and control mode restricts the adaptability of the pump under variable working conditions, secondary flow and separated flow in the pump are aggravated when the pump operates under a partial working condition, and the performance and the vibration noise are worsened. The traditional pump design and adjustment mode obviously cannot completely meet modern requirements, and new design concepts and methods must be explored to break through the bottleneck of the prior art.

The disrotatory impeller machine breaks through the traditional design concept and has the advantages of high power density, good vibration noise performance and the like. The present pair of rotor structures is found only in mixed and axial flow pumps. For example, "a counter-rotating-mixing pump structure" (patent No. 201710190776.8) discloses a dual-motor-driven counter-rotating-mixing pump using a double port ring sealing structure. "a high-efficiency counter-rotating axial-flow pump" (patent number: 201810473638.5) discloses a counter-rotating axial-flow pump, which makes reasonable flow setting for the wing profile installation angle of the coupled flow position of the front impeller and the rear impeller of the counter-rotating axial-flow pump. At present, no relevant patent report of a centrifugal pump with a rotor structure appears. The centrifugal pump rear impeller with the rotor structure provided by the invention has the advantages that the rotating speeds of the front impeller and the rear impeller are independently adjusted through the two motors so as to realize that the two impellers rotate in opposite rotating directions, the operating condition range of the pump is widened, the variable condition adaptability is enhanced, and more adjustable parameters are provided for intelligent control. Compared with the traditional design with the same parameters, the back impeller can obviously improve the power density by doing work again on the fluid, the negative prerotation energy of the inlet of the back impeller can reduce the outer diameter of the impeller, the linear speed of the impeller is reduced, and the vibration reduction and the noise reduction are facilitated. The invention has practical engineering application significance.

Disclosure of Invention

The invention provides a centrifugal pump with a rotor structure, which has high efficiency, good vibration noise performance and compact structure.

A centrifugal pump with a pair of rotor structures comprises a pump body, a volute, a front impeller, a rear impeller, an outer shaft, a rear pump cover, a gland A, a gland B, a mechanical seal, a deep groove ball bearing and an inner shaft. The centrifugal pump is mainly characterized in that: the front impeller is fixed on one end of the inner shaft, the other end of the inner shaft is connected to a standard three-phase asynchronous motor, a rear cover plate of the rear impeller is fixed with one end of the outer shaft, and the other end of the outer shaft is connected to the hollow shaft three-phase asynchronous motor. The inner shaft and the outer shaft rotate in opposite directions to drive the front impeller and the rear impeller to rotate in opposite directions. The front impeller is a centrifugal impeller, the number of blades of the front impeller is 6-15, the rear impeller is a radial impeller, the number of blades of the rear impeller is 4-12, and the number of blades of the front impeller is more than that of blades of the rear impeller. A radial clearance C is reserved between the front impeller and the rear impeller, and the value range of the radial clearance C is 2% -10% of the outer diameter D of the front impeller. The size of the gap must be proper, and too small a gap can cause large interference effect of the front impeller and the rear impeller and low efficiency; too large a gap may result in an increased amount of leakage. The inner shaft and the outer shaft are fixed by mounting a deep groove ball bearing, and the deep groove ball bearing and the mechanical seal are fixed by an inner shaft shoulder, a gland A and a gland B.

The invention has the beneficial effects that: the invention realizes that the two impellers rotate in opposite rotation directions by independently adjusting the rotation speeds of the front impeller and the rear impeller through the two motors, widens the operating condition range of the pump, enhances the adaptability to variable working conditions, and provides more adjustable parameters for intelligent control. Compared with the traditional design with the same parameters, the back impeller can obviously improve the power density by doing work again on the fluid, the negative prerotation energy of the inlet of the back impeller can reduce the outer diameter of the impeller, the linear speed of the impeller is reduced, and the vibration reduction and the noise reduction are facilitated.

Drawings

The invention will be further described with reference to the accompanying drawings in which:

fig. 1 is a schematic view showing the overall structure of a centrifugal pump having a rotor structure according to the present invention.

FIG. 2 is a schematic cross-sectional view of a centrifugal pump shaft having a rotor-to-rotor configuration according to the present invention.

Detailed Description

As shown in fig. 1, the centrifugal pump of the present invention has a structure of a pair of rotors, which includes a pump body 1, a volute 2, a front impeller 3, a rear impeller 4, an outer shaft 5, a rear pump cover 6, a gland a7, a gland B8, a mechanical seal 9, a deep groove ball bearing 10, and an inner shaft 11. The structure is mainly characterized in that the front impeller 3 is fixed on one end of the inner shaft 11 close to the pump inlet, the other end of the inner shaft 12 is connected to a standard three-phase asynchronous motor, the rear cover plate 12 of the rear impeller 4 is fixed on one end of the outer shaft 5 close to the pump inlet through screws, and the other end of the outer shaft 5 is connected to a hollow shaft three-phase asynchronous motor. The inner shaft 11 rotates in the opposite direction to the outer shaft 5, and the front impeller 3 and the rear impeller 4 are driven to rotate in the opposite direction. As shown in fig. 2, in the present embodiment, the front impeller 3 rotates in the clockwise direction and the rear impeller 4 rotates in the counterclockwise direction as viewed from the impeller inlet. The front impeller 3 is a centrifugal impeller with 8 blades, and the rear impeller 4 is a radial impeller with 6 blades. The front impeller 3 and the rear impeller 4 are provided with a radial clearance C, and the value range of the radial clearance C in the implementation is 3% of the outer diameter D of the front impeller 3. The inner shaft 11 and the outer shaft 5 are fixed by installing a deep groove ball bearing 10, and the deep groove ball bearing 10 and the mechanical seal 9 are fixed by a shaft shoulder of the inner shaft 11, a gland A7 and a gland B8.

The invention realizes that the two impellers rotate in opposite rotation directions by independently adjusting the rotation speeds of the front impeller and the rear impeller through the two motors, can widen the operating condition range of the pump, enhances the variable condition adaptability of the pump, and provides more adjustable parameters for intelligent control. Compared with the traditional design with the same parameters, the back impeller can obviously improve the power density by doing work again on the fluid, the negative prerotation energy of the inlet of the back impeller can reduce the outer diameter of the impeller, the linear speed of the impeller is reduced, and the vibration reduction and the noise reduction are facilitated.

Claims

1. A centrifugal pump with a pair of rotating substructures, comprising a pump body, a volute, a front impeller, a rear impeller, an outer shaft, a rear pump cover, a gland A, a gland B, a mechanical seal, a deep groove ball bearing and an inner The shaft is characterized in that the front impeller is fixed on one end of the inner shaft close to the pump inlet, the other end of the inner shaft is connected to a standard three-phase asynchronous motor, the rear cover plate of the rear impeller is fixed with the end of the outer shaft close to the pump inlet, and the outer shaft The other end is connected to the hollow shaft three-phase asynchronous motor. The rotation directions of the inner shaft and the outer shaft are opposite, which drives the front impeller and the rear impeller to rotate in opposite directions.

2. A centrifugal pump with a pair of rotating substructures as claimed in claim 1, wherein the front impeller is a centrifugal impeller with 6 to 15 blades, and the rear impeller is a radial impeller, and the number of blades is 4 to 12 pieces, the number of blades of the front impeller is more than that of the rear impeller.

3. a kind of centrifugal pump with a pair of rotating substructures as claimed in claim 1, is characterized in that, between the front impeller and the rear impeller, there is a radial gap C, and the value range of the radial gap C is outside the front impeller 2% to 10% of diameter D.

4. A centrifugal pump with a pair of rotating substructures as claimed in claim 1, wherein the inner shaft and the outer shaft are fixed by installing a deep groove ball bearing, and the deep groove ball bearing and the mechanical seal are fixed by the inner shaft shaft Shoulder, gland A and gland B are fixed.