A noise-reducing impeller for a variable frequency water pump

Abstract

This utility model discloses a noise-reducing impeller for a variable frequency water pump, including an impeller assembly and a volute. The impeller assembly is a precision rotating body with an integrated closed structure, consisting of long blades, short blades, a rear impeller cover plate, a front impeller cover plate, and a hub. The long and short blades are arranged alternately at a specific circumferential angle, using an "n long + n short" pattern, with a total of 2n blades, and the angles between adjacent blades are not equal. The volute is a spirally expanding flow channel structure surrounding the impeller assembly, with a rounded tongue. This structure, through the synergistic effect of the asymmetric blade layout and the optimized volute tongue, effectively disperses pressure pulsations and reduces hydraulic impact, thereby significantly reducing the noise during the operation of the variable frequency water pump.

Description

Technical Field

[0001] This utility model relates to the field of water pump impeller manufacturing technology, and in particular to a noise-reducing impeller for variable frequency water pumps. Background Technology

[0002] Variable frequency pumps are indispensable fluid transport equipment in modern industry, agriculture, and daily life. Traditional variable frequency pump impellers are typically designed and optimized for rated speeds. When operating at speeds other than rated speeds, the flow field within the impeller changes significantly, easily leading to flow separation, eddies, and severe pressure pulsations. These pressure pulsations are transmitted to the pump casing, causing structural vibrations and radiating strong airborne noise. Especially during wide-frequency operation, the "blade passing frequency" and its harmonic noise generated by the impeller rotation are particularly prominent, manifesting as sharp pure tones that greatly affect the acoustic comfort of the equipment and the application environment. Furthermore, the dynamic interference between the impeller and the volute tongue is another major noise source. In traditional designs, a smaller tongue clearance can slightly improve efficiency, but under variable speed conditions, it easily generates severe hydraulic impacts and eddy shedding, further exacerbating noise and vibration. Summary of the Invention

[0003] This application provides a noise-reducing impeller for a variable frequency water pump. By designing alternating long and short blades with unequal spacing on the impeller structure, and further optimizing the shape and gap of key parts of the volute tongue, the impeller and volute are designed in a coordinated manner to suppress noise generation at the source.

[0004] This application provides a noise-reducing impeller for a variable frequency water pump, characterized in that it includes:

[0005] The impeller assembly includes long blades, short blades, a rear impeller cover plate, a front impeller cover plate, and a hub. Both the long and short blades are fixedly connected between the rear and front impeller cover plates. The radially inner end of each long blade is fixedly connected to the hub. The hub is fixedly connected to both the rear and front impeller cover plates, together forming an integrated, closed-structure precision rotating body. The long and short blades are arranged alternately at a specific circumferential angle. The long and short blade design adopts an "n long + n short" pattern, with a total of 2n blades. The long and short blades are arranged alternately, and the angles between adjacent blades are not equal.

[0006] A volute is installed outside the impeller assembly. The volute is a spirally expanding flow channel structure surrounding the impeller assembly, and the volute tongue is a rounded tongue.

[0007] Preferably, the radial height of the short blade is 60%-80% of that of the long blade, and the terminal points of both the long blade and the short blade extend to the outer edge of the impeller to jointly form a working surface.

[0008] Preferably, the number of long and short blades is 4 to 6. Specifically, if n=6, there are a total of 12 blades. The angle between the first long blade and the first adjacent short blade is 34°, the angle between the first short blade and the second long blade is 26°, the angle between the second long blade and the second adjacent short blade is 34°, and so on.

[0009] Preferably, the gap between the outer diameter of the impeller assembly and the tongue of the volute is 10%-15% of the outer diameter of the impeller assembly.

[0010] Technical effects:

[0011] 1. This invention employs an asymmetrical design with alternating long and short blades at unequal spacing, effectively dispersing the concentrated pressure pulsation energy at the impeller outlet. This reduces the peak value and broadens the frequency band, transforming unpleasant, sharp pure tones into a more pleasing, wide-frequency noise, resulting in a significant decrease in overall sound pressure level. The designed short blades optimize the distribution of the internal flow field of the impeller, reducing low-speed and vortex regions, thus making the flow smoother. This not only helps reduce noise but also alleviates the alternating stress on the impeller caused by flow instability, potentially improving the impeller's fatigue life and operational reliability.

[0012] 2. This utility model greatly reduces the periodic impact intensity of high-speed water flow on the tongue by designing the volute tongue with rounded corners and increasing the gap between the impeller and the tongue to 10%-15% of the outer diameter, effectively suppressing the generation and shedding of eddies, and achieving noise reduction from another major sound source. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the impeller assembly in Embodiment 1 of this application;

[0014] Figure 2 This is a schematic diagram of the structure of the noise-reducing impeller for the variable frequency water pump in Embodiment 1 of this application;

[0015] 100 - Impeller assembly; 110 - Impeller rear cover plate; 120 - Impeller front cover plate; 130 - Long blade; 140 - Short blade; 150 - Hub; 200 - Volute; 210 - Volute tongue. Detailed Implementation

[0016] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0017] Example

[0018] Please refer to Figures 1-2A noise-reducing impeller for a variable frequency water pump includes an impeller assembly 100 and a volute 200. The impeller assembly 100 is a closed-structure precision rotating body integrally formed by precision casting or CNC machining. Its core includes long blades 130, short blades 140, an impeller rear cover plate 110, an impeller front cover plate 120, and a hub 150. The long blades 130 and short blades 140 are arranged alternately with a specific circumferential angle. The long and short blade design can adopt a "6+6" (6 long and 6 short) pattern, with a total of 12 blades. The long blades 130 and short blades 140 are arranged alternately, and the angles between adjacent blades are not equal. That is, the angle between the first long blade 130 and the first adjacent short blade 140 is 34°, the angle between the first short blade 140 and the second long blade 130 is 26°, and the angle between the second long blade 130 and the second adjacent short blade 140 is 34°, and so on in a cycle. Furthermore, the starting points of the long blade 130 and the short blade 140 are not the same. The long blade 130 starts from near the hub 150 to undertake the main head, while the short blade 140 starts from the middle flow channel to assist in guiding and splitting the flow. However, the terminal points of both blades extend to the outer edge of the impeller outlet to jointly form the working surface. The radial height of the short blade 140 is about 60% to 80% of that of the long blade 130.

[0019] A volute 200 is installed on the outside of the impeller assembly 100. The volute 200 is a spirally expanding flow channel structure surrounding the impeller assembly 100. Its function is to efficiently collect the fluid discharged from the impeller and convert kinetic energy into pressure energy. The gap between the outer diameter of the impeller assembly 100 and the tongue 210 of the volute is 10%-15% of the outer diameter of the impeller assembly 100, which can significantly reduce the interaction force between the impeller and the tongue and greatly reduce noise.

[0020] The volute tongue 210 is a rounded tongue, which can smooth the flow and reduce impact and eddy current shedding. The outlet of the volute can be connected to a diffuser cone to further reduce the flow velocity and recover kinetic energy. The volute 200 is rigidly connected to the pump body and motor housing by flanges or bolts to ensure system alignment and operational stability.

[0021] Typically, the impeller assembly 100 is circumferentially fixed to the motor shaft via an interference fit or key connection through the shaft hole at the center of its hub 150, and axially positioned by a shaft shoulder and a lock nut to ensure synchronized and precise rotation of the impeller and rotor. A volute is installed outside the impeller; the volute is a spirally expanding flow channel structure surrounding the impeller. Its inlet end face has a positioning stop and an O-ring groove for sealing with the pump body. It is rigidly connected to the pump body and motor housing by high-strength bolts to ensure system alignment and operational stability.

[0022] In another embodiment, the design of long and short blades in the impeller assembly can adopt a "5+5" (5 long and 5 short) pattern, with a total of 10 blades. Long blades 130 and short blades 140 are arranged alternately, and the included angles between adjacent blades are not equal. That is, the included angle between the first long blade 130 and the adjacent first short blade 140 is 40°, the included angle between the first short blade 140 and the second long blade 130 is 32°, the included angle between the second long blade 130 and the adjacent second short blade 140 is 40°, and so on.

[0023] If the total number of long and short blades in the impeller assembly is too small, i.e. the included angle is too large, it cannot effectively disperse the pulsation. If the total number of long and short blades in the impeller assembly is too large, i.e. the included angle is too small, it will lead to a narrow flow channel and reduced efficiency.

[0024] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the present invention.

[0025] Obviously, those skilled in the art can make various modifications and variations to this utility model without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this utility model and their equivalents, this utility model also intends to include these modifications and variations.

Claims

1. A noise-reducing impeller for a variable frequency water pump, characterized by, include: The impeller assembly includes long blades, short blades, a rear impeller cover plate, a front impeller cover plate, and a hub. Both the long and short blades are fixedly connected between the rear and front impeller cover plates. The radially inner end of the long blade is fixedly connected to the hub. The hub is fixedly connected to both the rear and front impeller cover plates, together forming an integrated, closed-structure precision rotating body. The long and short blades are arranged alternately at a specific circumferential angle. The long and short blade design adopts an "n long + n short" pattern, with a total of 2n blades. The long and short blades are arranged alternately, and the angles between adjacent blades are not equal. A volute is installed outside the impeller assembly. The volute is a spirally expanding flow channel structure surrounding the impeller assembly, and the volute tongue is a rounded tongue.

2. The noise-reducing impeller for a variable frequency water pump according to claim 1, characterized in that, The radial height of the short blade is 60%-80% of that of the long blade, and the terminal points of both the long blade and the short blade extend to the outer edge of the impeller to form a working surface.

3. The noise-reducing impeller of claim 1, wherein The design of the long and short blades has an n of 4 to 6. Specifically, if n=6, there are a total of 12 blades. The angle between the first long blade and the first adjacent short blade is 34°, the angle between the first short blade and the second long blade is 26°, the angle between the second long blade and the second adjacent short blade is 34°, and so on.

4. The noise-reducing impeller of claim 1, wherein The gap between the outer diameter of the impeller assembly and the tongue of the volute is 10%-15% of the outer diameter of the impeller assembly.

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