Pumping water chamber and design method

Abstract

The invention relates to the technical field of water pumps, and discloses a pumping water chamber and a design method, and relates to the technical field of water pumps, the pumping water chamber comprises a volute, N cavities are formed in the inner wall face of the volute, and the interval angle of every two adjacent cavities is # imgabs0 #. The water pump has the advantage that vibration noise generated during operation of the water pump can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of water pumps, and in particular to a pump water pressure chamber and a design method thereof. Background Art

[0002] When the existing pump body is in operation, during the rotation of the impeller, the pressure pulsation caused by the dynamic and static interference between the rotating impeller and the stationary volute wall will cause the water pump to generate vibration and noise during operation. Summary of the invention

[0003] In view of the deficiencies in the prior art, one of the purposes of the present application is to provide a pump water pressure chamber and a design method, which has the advantage of being able to reduce the vibration noise generated by the water pump during operation.

[0004] The above-mentioned purpose of the present application is achieved through the following technical solutions: The present application discloses a pump water chamber, comprising a volute, wherein the inner wall of the volute is provided with cavities, the number of cavities being N, and the interval angle between adjacent cavities being .

[0005] In a preferred example, the present application can be further configured as follows: a partition is provided in the cavity, and the material strength of the partition is not less than the material strength of the volute.

[0006] In a preferred example, the present application can be further configured as follows: the structure of the cavity is a polyhedron, a sphere or a hemisphere.

[0007] The present application also discloses a design method for a pump pressure chamber, which is used to design the above-mentioned pump pressure chamber: comprising the following steps: obtaining the inner wall pressure of the volute, obtaining the pressure value p per unit area acting on the volute wall of the centrifugal pump, and calculating the cavity inlet area. The cavity inlet area satisfies the formula: , where p is the pressure per unit area on the volute wall of the centrifugal pump, in N / m 2 ; A is the cavity inlet area, unit is m 2 ; is the surface tension of the liquid, in N / m; L is the perimeter length of the cavity opening, in m, the cavity volume calculation steps, the cavity volume satisfies the formula, , where V is the volume of the cavity structure, in m 3 ; A is the inlet area of ​​the cavity structure, in m 2 ; b is the depth of the cavity structure in the direction of the volute wall thickness, in m.

[0008] In a preferred example, the present application can be further configured as follows: , where H is the design head of the centrifugal pump, in m; ρ is the liquid density, in kg / m 3; g is the acceleration due to gravity, in m / s 2 . C is the pulsation coefficient, which is between 1.5 and 5.

[0009] In a preferred example, the present application can be further configured as follows: it also includes a quantity confirmation step, determining the number N of cavities opened on the volute wall surface, at which time the interval angle of each cavity is , unit: rad.

[0010] In a preferred example, the present application can be further configured as follows: it also includes a separation step, determining the number n of layers of the spacers in the cavity, and arranging them evenly in the cavity.

[0011] This application has the following advantages: By opening a cavity structure on the wall of the pump water pressure chamber and utilizing the compressibility of the air stored in the cavity, the pressure pulsation caused by dynamic and static interference is buffered, thereby achieving the purpose of reducing vibration and noise of the water pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the cavity and spacer structure of the present application.

[0013] Figure 2 It is a schematic diagram of the cavity and spacer structure of another embodiment of the present application.

[0014] Figure numerals: 1, cavity; 2, spacer. DETAILED DESCRIPTION

[0015] The present application is further described in detail below in conjunction with the accompanying drawings.

[0016] Reference Figure 1 and Figure 2 , is a pump water chamber disclosed in the present application, comprising a volute, wherein the inner wall surface of the volute is provided with a cavity 1, the cavity 1 has N cavities, and the interval angle of adjacent cavities 1 is There are n layers of spacers 2 in the cavity 1, n is 2 to 5, and the material strength of the spacers 2 is not less than the material strength of the volute. The structure of the cavity 1 is a polyhedron, a sphere or a hemisphere.

[0017] The present application also discloses a design method for a pump pressure chamber, which is used to design the above-mentioned pump pressure chamber: comprising the following steps: obtaining the inner wall pressure of the volute, obtaining the pressure value p per unit area acting on the volute wall of the centrifugal pump, , where H is the design head of the centrifugal pump, in m; ρ is the liquid density, in kg / m 3 ; g is the acceleration due to gravity, in m / s 2 . C is the pulsation coefficient, ranging from 1.5 to 5; Calculation steps for cavity 1 inlet area. The cavity 1 inlet area satisfies the formula, , where p is the pressure per unit area on the volute wall of the centrifugal pump, in N / m 2 ; A is the inlet area of ​​cavity 1, in m 2 ; is the surface tension of the liquid, in N / m; L is the perimeter length of the opening of cavity 1, in m; The volume calculation steps of cavity 1 are as follows: , where V is the volume of cavity 1 structure, in m 3 ; A is the inlet area of ​​cavity 1 structure, in m 2 ; b is the depth of the cavity 1 structure in the direction of the volute wall thickness, , k = 0.1 ~ 0.3, unit is m; The number confirmation step is to determine the number N of cavities 1 opened on the volute wall. At this time, the interval angle of each cavity 1 is , unit: rad; The separation step determines the number n of layers of the spacers 2 in the cavity 1, and they are evenly arranged in the cavity. Figure 1 , the spacers of the same layer can be arranged on the same vertical plane. In this case, the spacers of the same layer form a cross channel. In a preferred embodiment, the width of the cross channel in the width direction of the cavity accounts for 1 / 5-1 / 6 of the width of the cavity, and the width of the cross channel in the length direction of the cavity accounts for 1 / 5-1 / 6 of the length of the cavity. Figure 2 , the spacers 2 can also be arranged in a staggered manner.

[0018] In a specific embodiment, the centrifugal pump has a designed head H of 15 m, a volute wall thickness t of 0.012 m, a volute outlet diameter of 0.12 m, an axial width of 0.028 m, and a centrifugal pump conveying liquid of 20°C water. The cavity structure is selected as a cuboid.

[0019] The detailed design steps are as follows: S1: Combined with the Bernoulli equation, the pressure per unit area acting on the volute wall of the centrifugal pump is derived and calculated. (1) In the formula, take C=1.5.

[0020] S2: Considering the relationship between the pressure of the liquid in the volute on the volute wall and the surface tension of the liquid, assuming that the surface lengths of the rectangular cavity on the volute wall are a and c, then according to formula (2): (2) In the formula, , , .

[0021] Calculate the relationship ,in .Pick .

[0022] S3: According to step S2, the inlet area of ​​the cavity structure can be obtained. .

[0023] Furthermore, the volume of the cavity structure can be calculated according to formula (3): (3) In the formula, take .

[0024] S4: According to steps S1 to S3, the size of the cavity structure is 0.5 mm × 0.0006 mm × 1.2 mm. 36 cavities are opened on the volute wall by laser etching, and the interval angle of each cavity is 10°. Each cavity is divided into 5 layers of spacers, the thickness of the spacers is 0.05 mm, and the spacers are spaced 0.18 mm apart in the direction of the volute wall thickness and fixed by micro welding technology.

[0025] The implementation principle of this embodiment is: by opening a cavity structure on the wall of the pump water pressure chamber, the compressibility of the air stored in the cavity is utilized to buffer the pressure pulsation caused by the interference between movement and static, thereby achieving the purpose of reducing vibration and noise of the water pump.

[0026] The embodiments of this specific implementation method are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A pump water pressure chamber, characterized in that: The volute comprises a spiral case, wherein the inner wall surface of the spiral case is provided with at least one circle of cavities, wherein one circle of cavities has N cavities, and the interval angle between adjacent cavities is .

2. A pump water pressure chamber according to claim 1, characterized in that: A partition is arranged in the cavity, and the material strength of the partition is not less than the material strength of the volute.

3. A pump water pressure chamber according to claim 1 or 2, characterized in that: The structure of the cavity is a polyhedron, a sphere or a hemisphere.

4. A method for designing a pump pressure chamber, used for designing a pump pressure chamber as claimed in any one of claims 1 to 3, characterized in that: The method comprises the following steps: obtaining the inner wall pressure of the volute, obtaining the pressure value p per unit area acting on the volute wall of the centrifugal pump, and calculating the cavity inlet area. The cavity inlet area satisfies the formula: , where p is the pressure per unit area on the volute wall of the centrifugal pump, in N / m 2 ; A is the cavity inlet area, unit is m 2 ; is the surface tension of the liquid, in N / m; L is the perimeter length of the cavity opening, in meters. The cavity volume calculation steps are as follows: , where V is the volume of the cavity structure, in m 3 ; A is the inlet area of ​​the cavity structure, in m 2 ; b is the depth of the cavity structure in the direction of the volute wall thickness, in m.

5. The design method of a pump water chamber according to claim 4, characterized in that: , where H is the design head of the centrifugal pump, in m; ρ is the liquid density, in kg / m 3 ; g is the acceleration due to gravity, in m / s 2 ; C is the pulsation coefficient, which is between 1.5 and 5.

6. The design method of a pump water chamber according to claim 4, characterized in that: The step of confirming the number is also included, determining the number N of cavities opened on the volute wall surface, at which time the interval angle of each cavity is , unit: rad.

7. A method for designing a pump water pressure chamber according to claim 4 or 6, characterized in that: The method also includes a separation step, determining the number n of layered partitions in the cavity, and evenly arranging the partitions in the cavity.

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