Anti-cavitation device and centrifugal pump

Abstract

The utility model relates to the field of pumps, in particular to an anti-cavitation device which comprises an outer ring and an inner ring which are coaxially arranged, a backflow channel allowing media to flow back is formed between the outer ring and the inner ring, and the tail end of the outer ring is bent inwards in the radial direction to form an inverted-hook-shaped guide ring in the backflow direction of the backflow channel. The bending direction of the guide ring is opposite to the backflow direction of a medium in the backflow channel, and a gap exists between the tip end of the guide ring and the tail end of the inner ring so that the medium in the backflow channel can be discharged. According to the centrifugal pump, the cavitation phenomenon of the centrifugal pump is greatly reduced, and the stability of the centrifugal pump during operation is improved. The utility model further provides the centrifugal pump.

Description

Technical Field

[0001] The utility model relates to the field of pumps, in particular to an anti-cavitation device and a centrifugal pump. Background Art

[0002] A centrifugal pump is a pump that transports liquid by the centrifugal force generated by the rotation of the impeller. Its conventional structure is as described in the application number "CN202410091192.5", including a variable frequency speed regulating motor, an impeller inlet seal guide structure, an impeller rear side pressure balance seal structure and a volute impeller side inner wall buffer groove structure. The impeller inlet seal guide structure is arranged on the impeller inlet side for guide and sealing. The impeller rear side pressure balance seal structure is arranged between the impeller and the volute rear cover plate for pressure balance and sealing. The volute is buffered and maintained in balance by setting a volute impeller side inner wall buffer groove structure. The pump axial force has a good balancing effect, which can reduce damage to the pump shaft and improve the safety of the pump shaft.

[0003] However, the existing traditional centrifugal pumps have the following defects: slightly in front of the blade inlet, due to the rotation of the impeller, the medium flow velocity increases, the kinetic energy increases, the pressure energy decreases, and it is easy to produce backflow, vortex, cavitation and other phenomena. When cavitation occurs in the pump, bubbles are continuously generated in the high-pressure area and then burst, which will produce noise and vibration; at the same time, when the cavitation bubbles condense, the metal surface is impacted by high frequencies above 600Hz, causing the metal grains on the metal surface to loosen and peel off, affecting the normal operation of the pump, so it is urgent to solve the problem. Utility Model Content

[0004] In order to avoid and overcome the technical problems existing in the prior art, the utility model provides an anti-cavitation device. The utility model significantly reduces the cavitation phenomenon of the centrifugal pump and improves the stability of the centrifugal pump during operation. The utility model also provides a centrifugal pump.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] An anti-cavitation device comprises an outer ring and an inner ring arranged coaxially, a reflux channel for medium reflux is provided between the outer ring and the inner ring, along the reflux direction of the reflux channel, the tail end of the outer ring is bent radially inward to form a guide ring in the shape of an inverted hook, the bending direction of the guide ring is opposite to the reflux direction of the medium in the reflux channel, and there is a gap between the tip of the guide ring and the tail end of the inner ring for the medium in the reflux channel to be discharged.

[0007] As a further solution of the utility model: along the reflux direction of the reflux channel, the head end of the inner ring is arc-shaped, and a guide slope is provided on the inner side of the tail end of the inner ring, and the inclination direction of the guide slope corresponds to the same bending direction of the guide ring.

[0008] As a further solution of the utility model: the inner diameter of the guide ring is equal to the inner diameter of the inner ring.

[0009] As a further solution of the utility model: the outer ring and the inner ring are connected and fixed by connecting ribs arranged in the radial direction, the connecting ribs are evenly arranged along the circumference of the inner ring, and two adjacent connecting ribs, the outer ring and the inner ring are enclosed to form a reflux channel.

[0010] As a further solution of the utility model: the outer ring, the inner ring and the connecting ribs are integrally formed.

[0011] A centrifugal pump, wherein the anti-cavitation device is arranged at the upstream end of the impeller in the pump body; a positioning step is provided in the pump body along the circumferential direction, the outer ring of the anti-cavitation device abuts against the positioning step, the inner diameter of the outer ring is correspondingly equal to the inner diameter of the positioning step; the inlet diameter of the impeller is correspondingly equal to the inner diameter of the inner ring.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] 1. The utility model introduces the medium whose pressure energy is reduced due to the pre-rotation of the impeller at the maximum outer edge position of the impeller inlet leading edge into the reflux channel of the anti-cavitation device, and then enters the impeller after de-rotation, de-speeding and pressurization. The impeller works and pressurizes, thereby reducing the cavitation caused by the reduction of the medium pressure energy. After the medium refluxes and is de-rotated and pressurized, the surge at the impeller inlet can be eliminated, thereby realizing the stable operation of the pump from the BEP point to the dead point.

[0014] 2. The utility model redirects the medium in the reflux channel into the pump body through the cooperation of the guide ring at the tail end of the outer ring of the anti-cavitation device and the guide slope at the tail end of the inner ring, thereby reducing the pressure pulsation at the inlet and outlet of the high suction specific speed pump and improving the stability of the centrifugal pump during operation.

[0015] 3. The utility model directly presses the anti-cavitation device onto the positioning step in the pump body, which is easy to install and does not affect parameters such as pump efficiency, shaft power and pump head. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is an assembly diagram of the utility model.

[0017] Figure 2 It is a side view of the anti-cavitation device in the utility model.

[0018] Figure 3 This is a simulation diagram of the flow field of a centrifugal pump when no anti-cavitation device is installed.

[0019] Figure 4 This is a simulation diagram of the flow field of a centrifugal pump when an anti-cavitation device is installed.

[0020] In the figure:

[0021] 1. Pump body; 2. Impeller; 3. Anti-cavitation device;

[0022] 31. outer ring; 311. guide ring; 32. inner ring; 321. guide slope;

[0023] 33. Reflux channel; 34. Connecting ribs. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] See also Figures 1-2 In the embodiment of the utility model, an anti-cavitation device and a centrifugal pump are provided. The anti-cavitation device 3 is installed in the pump body 1 and arranged adjacent to the inlet of the impeller 2. The anti-cavitation device 3 includes an outer ring 31 and an inner ring 32, wherein the length of the outer ring 31 is greater than the length of the inner ring 32. One end adjacent to the impeller 2 is the head end of the outer ring 31 and the inner ring 32, the head ends of the outer ring 31 and the inner ring 32 are arranged flush, and the inner diameter of the inner ring 32 is equal to the inlet diameter of the impeller 2.

[0026] The inner wall of the pump body 1 is provided with a positioning step along the circumferential direction, the end surface of the outer ring 31 abuts against the positioning step, and the inner diameter of the outer ring 31 is equal to the inner diameter of the positioning step.

[0027] The outer ring 31 and the inner ring 32 are connected and fixed by multiple groups of connecting ribs 34. The end faces of each connecting rib 34 are smooth, and each connecting rib 34 is arranged radially along the inner ring 32. The length of the connecting rib 34 is less than the length of the inner ring 32, and the position of the connecting rib 34 is located in the middle of the inner ring 32. Each connecting rib 34 is integrally formed with the outer ring 31 and the inner ring 32. Two adjacent connecting ribs 34, the outer ring 31 and the inner ring 32 enclose a group of reflux channels 33. Each reflux channel 33 is evenly arranged along the circumference of the inner ring 32 to provide reflux for the medium at the inlet of the impeller 2.

[0028] The tail end of the outer ring 31 is bent radially to form a guide ring 311. The guide ring 311 is in a smooth hook shape. The bending direction is the same as the medium conveying direction in the pump body 1 and opposite to the medium flowing direction in the reflux channel 33. The inner diameter of the guide ring 311 is equal to the inner diameter of the inner ring 32. After the medium in the reflux channel 33 leaves the reflux channel 33, it rejoins the medium in the pump body 1 along the arc surface of the guide ring 311 and is transported to the impeller 2. The tail end of the inner ring 32 is provided with a guide slope 321 that matches the guide ring 311. The inclination direction of the guide slope 321 is the same as the bending direction of the guide ring 311. After the medium leaves the reflux channel 33, it is discharged from the gap between the guide slope 321 and the guide ring 311.

[0029] like Figure 3 As shown, when the anti-cavitation device 3 is not installed, when a certain pump type is operating at a small flow rate, the flow at the impeller inlet is complex and chaotic, the generated vortex is unevenly distributed, and the backflow is particularly serious, affecting the normal performance and operation of the pump.

[0030] like Figure 4 As shown, after the anti-cavitation device 3 is installed, the flow field and turbulence of the centrifugal pump are significantly improved at the same flow rate.

[0031] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0032] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

Claims

1. An anti-cavitation device, characterized in that: The anti-cavitation device (3) comprises an outer ring (31) and an inner ring (32) which are coaxially arranged. A reflux channel (33) for medium reflux is provided between the outer ring (31) and the inner ring (32). Along the reflux direction of the reflux channel (33), the tail end of the outer ring (31) is bent radially inward to form a guide ring (311) in the shape of an inverted hook. The bending direction of the guide ring (311) is opposite to the reflux direction of the medium in the reflux channel (33). A gap is provided between the tip of the guide ring (311) and the tail end of the inner ring (32) to allow the medium in the reflux channel (33) to be discharged.

2. The anti-cavitation device according to claim 1, characterized in that: Along the reflux direction of the reflux channel (33), the head end of the inner ring (32) is in an arc shape, and a guide slope (321) is provided on the inner side of the tail end of the inner ring (32). The inclination direction of the guide slope (321) corresponds to the same bending direction of the guide ring (311).

3. The anti-cavitation device according to claim 1, characterized in that: The inner diameter of the guide ring (311) is correspondingly equal to the inner diameter of the inner ring (32).

4. An anti-cavitation device according to any one of claims 1 to 3, characterized in that: The outer ring (31) and the inner ring (32) are connected and fixed by connecting ribs (34) arranged in a radial direction. The connecting ribs (34) are evenly arranged along the circumference of the inner ring (32). Two adjacent connecting ribs (34) and the outer ring (31) and the inner ring (32) enclose a reflux channel (33).

5. The anti-cavitation device according to claim 4, characterized in that: The outer ring (31), the inner ring (32) and the connecting ribs (34) are integrally formed.

6. A centrifugal pump, characterized in that: The anti-cavitation device (3) as described in any one of claims 1 to 3 is arranged at the upstream end of the impeller (2) in the pump body (1); a positioning step is provided in the pump body (1) along the circumferential direction, the outer ring (31) of the anti-cavitation device (3) abuts against the positioning step, and the inner diameter of the outer ring (31) is correspondingly equal to the inner diameter of the positioning step; the inlet diameter of the impeller (2) is correspondingly equal to the inner diameter of the inner ring (32).

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