Centrifugal pump

Abstract

A centrifugal pump comprises a water pump body, a water pump rotor and a central pump shaft, the central pump shaft is positioned and installed on the central axis in the water pump body, the water pump rotor is arranged outside the central pump shaft in a sleeved mode, an impeller is arranged on the upper portion of the water pump rotor, and a gasket is arranged between the impeller and the central pump shaft. An axial limiting gap is formed between the impeller and the gasket, and the width of the limiting gap is 1-5 mm; a plurality of jet flow holes are formed in the upper surface of the impeller. According to the centrifugal pump, a limiting gap is optimally designed, bubbles are discharged from a pump cavity, the severity of the cavitation phenomenon is rapidly reduced, a flow dividing step is designed at a water pump opening, the water flow speed of the center of the water pump opening is high, the water flow speed of the edge is low, the bubbles in hot water adhere to the inner wall of a water inlet of the water pump, and the fusion degree is increased; bubbles float upwards and are prevented from being sucked into a pump cavity to form air binding. High-pressure water flows back to an inlet of the impeller by adding the jet holes, and cavitation generated by negative pressure in a central area can be effectively reduced.

Description

[Technical field] The invention relates to the technical field of centrifugal pumps in water supply equipment, and in particular to the technical field of centrifugal pump cavitation performance optimization. [Background technology] The kitchen hot water / boiling water supply system used in the kitchen must be equipped with a heating system. The heating system is placed under the countertop with the main unit, and the water faucet is installed on the countertop. After the water supply is heated, the centrifugal pump can be started to pump the hot water up and discharge it from the faucet through the pipeline for users to use. However, in actual use, due to the high water temperature of the hot tank in the heating system, the water pump is prone to cavitation during operation, resulting in a decrease in flow or even no water.

[0003] The so-called cavitation phenomenon refers to the phenomenon that occurs in fluid power equipment, such as water pumps and turbines. When the fluid velocity exceeds a certain limit, bubbles will form on the surface of the equipment. These bubbles will then quickly collapse, generating high pressure and high temperature, affecting water supply, fluid flow, and even causing equipment damage. Cavitation performance refers to the ability of fluid power mechanical equipment to resist or utilize cavitation during operation.

[0004] There is usually a limiting gap between the impeller and gasket of a water pump, and the limiting gap will cause cavitation of high-temperature hot water in the pump chamber, and then the accumulation of bubbles will affect the water flow rate; and because the pressure at the edge of the pump chamber is high and the pressure in the center is low when the water pump is working, negative pressure will be formed in the center area, which will more easily lead to serious cavitation. Therefore, considering reducing the negative pressure in the center area and improving the pressure distribution can further optimize the cavitation performance of the equipment. [Summary of the invention] In view of the problems existing in the prior art, the present invention proposes a centrifugal pump with optimized cavitation performance, redesigns the limit gap to help the bubbles to be discharged from the pump cavity, quickly reduces the severity of the cavitation phenomenon, and considers designing a diversion step at the water pump port to make the water flow speed in the center of the water pump port fast and the water flow speed at the edge slow, so that the bubbles in the hot water adhere to the inner wall of the water inlet of the water pump, the degree of fusion becomes greater, and the bubbles float up to avoid the bubbles being sucked into the pump cavity to form air binding; adding jet holes to allow high-pressure water to flow back to the impeller inlet can effectively reduce the cavitation caused by the negative pressure in the central area.

[0006] The present invention relates to a centrifugal pump, comprising a water pump body, a water pump rotor and a central pump shaft, wherein the central pump shaft is positioned and installed on the central axis inside the water pump body, and the water pump rotor is sleeved outside the central pump shaft, and is characterized in that an impeller is provided on the upper part of the water pump rotor, and a gasket is provided between the impeller and the central pump shaft, and an axial limiting gap is provided between the impeller and the gasket, and the width range of the limiting gap is: 1mm~5mm; a plurality of jet holes are provided on the upper surface of the impeller.

[0007] The water pump body comprises a bottom shell and an upper cover, wherein the central pump shaft and the water pump rotor are mostly placed in the bottom shell, and the impeller is located in the upper cover, and the water pump water inlet and water pump outlet are arranged on the upper cover.

[0008] A water pump inlet is arranged in the center of the upper cover above the water pump body, and the axis of the water pump inlet is coaxial with the axis of the central pump shaft.

[0009] A water pump outlet is provided on the side of the upper cover above the water pump body. Specifically, the water pump outlet corresponds to the tangential direction of the impeller, that is, the axial direction of the water pump outlet is coaxial with the tangential direction of the impeller.

[0010] The impeller comprises an impeller bottom plate, an impeller upper cover and blades. The blades are arranged between the impeller bottom plate and the impeller upper cover, and a liquid flow channel is formed between a plurality of blades.

[0011] The impeller upper cover is a conical structure, and the portion close to the central axis is higher than the portion away from the central axis.

[0012] The diameter of the jet hole is 1-3 mm.

[0013] The relationship between the diameter D of the jet hole and the liquid flow channel P in the impeller is: 1. When P≥8, D=1mm; 2. When 4≤P≤7, D=2mm; 3. When P≤3, D=3mm.

[0014] A diversion step is provided inside the water inlet of the water pump near the impeller, and the diversion step is a ring structure protruding inwardly on the inner wall of the water inlet of the water pump.

[0015] The width L of the diverter step is associated with the inner diameter R of the water inlet of the water pump, wherein the width L of the diverter step=the inner radius R / 3 of the water inlet of the water pump, and wherein L is not less than 2 mm and not more than 12 mm.

[0016] The centrifugal pump with optimized cavitation performance involved in the present invention helps the bubbles to be discharged from the pump cavity by optimizing the design of the limit gap width, thereby quickly reducing the severity of the cavitation phenomenon. By designing a diversion step at the water pump port, the water flow speed in the center of the water pump port is fast and the water flow speed at the edge is slow, so that the bubbles in the hot water adhere to the inner wall of the water pump inlet, the degree of fusion becomes larger, and the bubbles float up to avoid the bubbles being sucked into the pump cavity to form air binding; adding jet holes to allow high-pressure water to flow back to the impeller inlet can effectively reduce the cavitation caused by the negative pressure in the central area.

Brief Description of the Drawings

[0018] D: Limit clearance. [Specific implementation method] The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments, examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] Please refer to the attached Figure 1 , which shows a structural diagram of the centrifugal pump involved in the present invention, wherein the centrifugal pump includes a water pump body 10, a water pump rotor 20 and a central pump shaft 30, wherein the central pump shaft 30 is positioned and installed on the central axis in the water pump body 10, and the water pump rotor 20 is sleeved outside the central pump shaft 30, characterized in that an impeller 40 is provided on the upper part of the water pump rotor 20, and a gasket 50 is provided between the impeller 40 and the central pump shaft 30, and an axial limit gap D is provided between the impeller 40 and the gasket 50, and the width range of the limit gap D is: 1mm~5mm; high-temperature hot water is more likely to produce cavitation in the pump cavity, and then bubbles gather to affect the water flow rate. This solution redesigns the limit gap, and its value is between 1mm~5mm, so that the impeller 40 can reduce the dynamic friction during rotation.

[0022] When hot water cavitation occurs in the pump chamber, the water pump flow rate becomes smaller, the work done by the rotor becomes smaller, the speed will increase, and the rotor will rotate and float due to the bubbles. This process can effectively help the bubbles in the pump chamber to be discharged from the water outlet. After the exhaust is completed, the water pump rotor 20 will return to the normal working position due to the increased work done and gravity.

[0023] The water pump body 10 includes a bottom shell 11 and an upper cover 12 , wherein the central pump shaft 30 and the water pump rotor 20 are mostly placed in the bottom shell 11 , and the impeller 40 is located in the upper cover 12 , and a water pump inlet 13 and a water pump outlet 14 are provided on the upper cover 12 .

[0024] A water pump water inlet 13 is provided in the center of the upper cover 12 above the water pump body 10 , and the axis of the water pump water inlet 13 is coaxial with the axis of the central pump shaft 30 .

[0025] A water pump outlet 14 is provided on the side of the upper cover 12 above the water pump body 10 . Specifically, the water pump outlet 14 corresponds to the tangential direction of the impeller, that is, the axial direction of the water pump outlet 14 is coaxial with the tangential direction of the impeller 40 .

[0026] The impeller 40 includes an impeller bottom plate 42, an impeller upper cover 43 and blades 44. The blades 44 are arranged between the impeller bottom plate 42 and the impeller upper cover 43. Between the blades, the space between every two blades and the impeller upper cover and the impeller bottom plate forms a liquid flow channel 45. When the impeller rotates, the liquid flow is pumped through the liquid flow channel 45. A plurality of jet holes 41 are arranged on the upper surface of the impeller upper cover 43.

[0027] The jet holes 41 are arranged above each liquid flow channel 45; high-temperature hot water is more likely to cause cavitation in the pump chamber. When the water pump is working, the pressure at the edge of the pump chamber is high and the pressure in the center is low. Adding the jet holes 41 to allow high-pressure water to flow back to the impeller inlet can effectively reduce the cavitation caused by the negative pressure in the center area.

[0028] The impeller upper cover 12 is a conical structure, and the portion close to the central axis is higher than the portion away from the central axis.

[0029] The diameter of the jet hole 41 is 1-3 mm.

[0030] The relationship between the diameter D of the jet hole 41 and the liquid flow channel P in the impeller 40 is: 1. When P≥8, D=1mm; 2. When 4≤P≤7, D=2mm; 3. When P≤3, D=3mm.

[0031] A diverter step 15 is provided inside the water inlet 13 of the water pump near the impeller 40 . The diverter step 15 is a ring structure protruding inwardly from the inner wall of the water inlet 13 of the water pump.

[0032] The width of the diverter step 15 is 2-12 mm. The width L of the diverter step 15 is related to the inner diameter R of the water pump inlet 13, and the width L of the diverter step 15 = the inner radius R / 3 of the water pump inlet, where L is not less than 2 mm and not greater than 12 mm; the centrifugal pump is vertically installed at the bottom of the hot tank, and the water pump inlet 13 faces upward; when the centrifugal pump is working, when the water pump rotor 20 rotates, hot water enters the water pump cavity from the water pump inlet 13. Due to the effect of the diverter step 15, the center flow velocity of the water pump inlet 13 is fast and the edge flow velocity is slow (negative pressure distribution). At this time, when the bubbles in the hot water are precipitated, they will adhere to the inner wall of the water pump inlet 13 due to the wall attachment effect, and the bubbles attached to the wall will gradually merge with the new bubbles to become larger; when the bubbles attached to the wall become larger, their buoyancy is greater than the adhesion force + the negative pressure suction of the water pump, and the bubbles will float up and dissipate, effectively preventing the bubbles from being sucked into the pump cavity to form air binding.

[0033] The centrifugal pump with optimized cavitation performance involved in the present invention helps the bubbles to be discharged from the pump cavity by optimizing the design of the limit gap width, thereby quickly reducing the severity of the cavitation phenomenon. By designing a diversion step at the water pump port, the water flow speed in the center of the water pump port is fast and the water flow speed at the edge is slow, so that the bubbles in the hot water adhere to the inner wall of the water pump inlet, the degree of fusion becomes larger, and the bubbles float up to avoid the bubbles being sucked into the pump cavity to form air binding; adding jet holes to allow high-pressure water to flow back to the impeller inlet can effectively reduce the cavitation caused by the negative pressure in the central area.

[0034] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. A centrifugal pump, comprising a water pump body, a water pump rotor and a central pump shaft, wherein the central pump shaft is positioned and installed on the central axis of the water pump body, and the water pump rotor is sleeved outside the central pump shaft, characterized in that: An impeller is arranged on the upper part of the water pump rotor, a gasket is arranged between the impeller and the central pump shaft, an axial limiting gap is arranged between the impeller and the gasket, and the width range of the limiting gap is: 1mm~5mm; a plurality of jet holes are arranged on the upper surface of the impeller.

2. The centrifugal pump according to claim 1, characterized in that: The water pump body comprises a bottom shell and an upper cover, wherein the central pump shaft and the water pump rotor are mostly placed in the bottom shell, and the impeller is located in the upper cover, and the water pump water inlet and water pump outlet are arranged on the upper cover.

3. The centrifugal pump according to claim 1, characterized in that: A water pump inlet is arranged in the center of the upper cover above the water pump body, and the axis of the water pump inlet is coaxial with the axis of the central pump shaft.

4. The centrifugal pump according to claim 1, characterized in that: A water pump outlet is provided on the side of the upper cover above the water pump body. Specifically, the water pump outlet corresponds to the tangential direction of the impeller, that is, the axial direction of the water pump outlet is coaxial with the tangential direction of the impeller.

5. The centrifugal pump according to claim 1, characterized in that: The impeller comprises an impeller bottom plate, an impeller upper cover and blades. The blades are arranged between the impeller bottom plate and the impeller upper cover, and a liquid flow channel is formed between a plurality of blades.

6. The centrifugal pump according to claim 1, characterized in that: The impeller upper cover is a conical structure, and the portion close to the central axis is higher than the portion away from the central axis.

7. A centrifugal pump according to claim 1, characterized in that: The diameter of the jet hole is 1-3 mm.

8. The centrifugal pump according to claim 1, characterized in that: The relationship between the diameter D of the jet hole and the liquid flow channel P in the impeller is:

1. When P≥8, D=1mm; 2. When 4≤P≤7, D=2mm; 3. When P≤3, D=3mm.

9. The centrifugal pump according to claim 1, characterized in that: A diversion step is provided inside the water inlet of the water pump near the impeller, and the diversion step is a ring structure protruding inwardly on the inner wall of the water inlet of the water pump.

10. The centrifugal pump according to claim 9, characterized in that: The width L of the diverter step is associated with the inner diameter R of the water inlet of the water pump, wherein the width L of the diverter step=the inner radius R / 3 of the water inlet of the water pump, and wherein L is not less than 2 mm and not more than 12 mm.

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