Anti-cavitation centrifugal pump impeller

Abstract

The utility model discloses an anti-cavitation centrifugal pump impeller, which relates to the technical field of centrifugal pumps and comprises an impeller body, a main shaft and a secondary blade, the impeller body is connected to one end of the main shaft through a main shaft bolt, an opening is formed in the middle of a cavity of the impeller body to form an inlet, and the secondary blade is arranged on the main shaft at the inlet. The secondary blades can effectively reduce necessary cavitation allowance, the installed centrifugal pump can be optimized and designed conveniently, and cavitation of an impeller of an original centrifugal pump is restrained while pump lift is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of centrifugal pumps, and more specifically to an anti-cavitation centrifugal pump impeller. Background Art

[0002] When the pressure of the liquid in the pump is reduced to the vaporization pressure at a certain temperature, bubbles will be generated in the liquid. When it flows to the high pressure, it will collapse, causing noise and vibration in the pump, resulting in a decrease in pump performance and even corrosion of flow-through parts. The existing technical solutions to improve the anti-cavitation performance of centrifugal pumps mainly include: optimizing design, perforating blades or arranging obstacles and inducers.

[0003] In the prior art, a patent document with a publication number of CN109209987B discloses an anti-cavitation centrifugal pump impeller and a centrifugal pump. The anti-cavitation centrifugal pump impeller includes blades, a rear cover plate and small blades, and the small blades are located on the back of the blades and are fixedly connected to the rear cover plate. By arranging the small blades to improve the low-pressure area inside the impeller flow channel, the volume of cavitation bubbles generated by the centrifugal pump when cavitation occurs is inhibited, and the anti-cavitation performance of the centrifugal pump is improved. This method is more complicated to install and is not conducive to upgrading and optimizing the installed centrifugal pump. Utility Model Content

[0004] In order to overcome the defects existing in the above-mentioned prior art, the purpose of the utility model is to provide a centrifugal pump impeller with an anti-cavitation function, which achieves the technical effect of reducing the required cavitation margin by arranging secondary blades near the inlet of the impeller axis.

[0005] In order to achieve the above objectives, the technical solution adopted by the utility model is:

[0006] A cavitation-resistant centrifugal pump impeller, characterized in that it includes an impeller body, a main shaft and secondary blades, the impeller body is connected to one end of the main shaft through a main shaft bolt, an opening is provided in the middle of the impeller body cavity to form an inlet, and the secondary blades are arranged on the main shaft located in the inlet.

[0007] Preferably, the secondary blades are fixed on the main shaft bolts.

[0008] Preferably, the secondary blades are designed as high-efficiency centrifugal blades with three-dimensional curved surfaces.

[0009] Preferably, the secondary blades and the impeller blade rotation direction rotate synchronously with the main shaft.

[0010] Preferably, the number of the secondary blades corresponds to the number of impeller blades.

[0011] Preferably, the wrap angle of the secondary blades is set at 30°~60°.

[0012] Preferably, the spindle bolt is divided into two parts, an upper part and a lower part, the lower part is cylindrical, and the upper part is designed as a regular hexagon.

[0013] Preferably, the threads on the inner sides of the upper and lower parts of the main shaft bolt are designed identically, and the spiral direction is opposite to the rotation direction of the main shaft.

[0014] Preferably, the spindle bolt is provided with rounded corners.

[0015] Preferably, the secondary blades and the main shaft bolts are fixed by welding.

[0016] Beneficial effects of the utility model:

[0017] 1. Compared with the existing technology, the centrifugal secondary blades are installed near the inlet of the impeller, rotate coaxially with the impeller, and start to work before the leading edge of the impeller blades, thereby increasing the pump head and the utilization efficiency of the main shaft rotation work. After the liquid flow passes through the blades and works, the total pressure has been increased when it reaches the impeller blades, which directly increases the effective cavitation margin of the pump (that is, the energy remaining after the total head of the liquid is subtracted from the vaporization pressure head), and suppresses cavitation on the pump blades.

[0018] 2. In the present invention, due to the curvature of the blades and the centrifugal force generated by the rotation, the centrifugal pump will inevitably generate a vortex on the suction side (back side) of the blades, thereby generating a low-pressure area. The secondary blades of this design rotate at the same frequency as the impeller, which has a pre-swirl effect on the liquid flow before it reaches the blade flow channel, thereby suppressing the vortex effect.

[0019] 3. In the utility model, the secondary blades are fixedly mounted on the main shaft bolts and can be installed and disassembled together with the main shaft bolts, so replacement is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the impeller of the utility model;

[0021] Figure 2 This is a schematic diagram of the installation of the secondary blades of the utility model;

[0022] Reference numerals:

[0023] 1. Impeller body; 2. Main shaft; 3. Secondary blades; 4. Main shaft bolts. DETAILED DESCRIPTION

[0024] The concept, specific structure and technical effects of the present invention will be clearly and completely described below in combination with the embodiments and drawings to fully understand the purpose, features and effects of the present invention.

[0025] Example 1

[0026] like Figure 1 and Figure 2 An anti-cavitation centrifugal pump impeller shown includes an impeller body 1, a main shaft 2 and secondary blades 3. The impeller body 1 is connected to one end of the main shaft 2 through a main shaft bolt 4. An opening is provided in the middle of the cavity of the impeller body 1 to form an inlet. The secondary blades 3 are arranged on the main shaft 2 located in the inlet.

[0027] As an implementation method of this embodiment, the secondary blade 3 is designed as a high-efficiency centrifugal blade with a three-dimensional curved surface. The secondary blade 3 and the impeller blade rotation direction rotate synchronously with the main shaft 2. The number of blades of the secondary blade 3 corresponds to the number of impeller blades, and the number is generally 6. The wrap angle of the secondary blade 3 is set at 30°~60°, and the method refers to the impeller blade design method of the centrifugal pump.

[0028] The lowest pressure point in the pump impeller usually occurs on the blade suction surface slightly behind the inlet on the back of the blade, which is also the initial cavitation position. The main reasons are: 1. The local hydraulic loss caused by the change in the flow channel cross-section causes the pressure drop; 2. The pressure drop caused by the flow around the blades; 3. The velocity and height difference between the impeller inlet front section and the impeller inlet rear section causes the pressure drop (i.e., head difference or total pressure difference).

[0029] The secondary blades 3 of centrifugal design are installed near the impeller inlet, rotate coaxially with the impeller 1, and start to work before the leading edge of the impeller blades, thereby increasing the pump head and improving the utilization efficiency of the rotation work of the main shaft 2. After the liquid flow passes through the blades to do work, the total pressure has been increased when it reaches the impeller blades, which directly increases the effective cavitation margin of the pump (that is, the energy remaining after deducting the vaporization pressure head from the total head of the liquid), and suppresses the cavitation on the pump blades. Due to the curvature of the blades and the centrifugal force generated by the rotation, the centrifugal pump will inevitably produce a flow around the suction side (back side) of the blades, thereby generating a low-pressure area. The blades of this design rotate at the same frequency as the impeller, which has a pre-swirl effect on the liquid flow before it reaches the blade flow channel, thereby suppressing the influence of the flow around.

[0030] As an implementation method of this embodiment, the secondary blade 3 is fixed on the main shaft bolt 4. The secondary blade 3 is fixedly mounted on the main shaft bolt 4, and is installed and disassembled together with the main shaft bolt 4. It has the following convenience advantages: 1. It can be selected whether to use it according to the operating conditions. When not in use, it can be replaced with a conventional main shaft bolt, which is convenient for installation and disassembly. 2. It is designed independently from the impeller. Due to its convenience, it can be used as a post-installed auxiliary device. If the impeller that has been designed has new head and cavitation requirements when the conditions change, the requirements can be met by designing and adding a main shaft bolt with secondary blades. 3. Under extreme cavitation conditions, the secondary blade 3 cavitation occurs preferentially than the impeller blade, which adds a layer of protection to the original impeller. Due to its small size and easy replacement, it can reduce the sunk cost of dealing with extreme conditions. 4. It has strong versatility and can be installed on other pump shafts of the same size.

[0031] Example 2

[0032] This embodiment further illustrates the present application based on the above embodiments. Figure 2 As shown, the spindle bolt 4 is divided into two parts, the lower part is cylindrical and the upper part is a regular hexagonal design. The upper part of this design is a conventional regular hexagonal structure, which is used for screwing during installation and disassembly; the lower part is a cylinder with centrifugal blades on the outside.

[0033] As an implementation mode of this embodiment, the threads on the inner sides of the upper and lower parts of the main shaft bolt 4 are designed identically, and the spiral direction is opposite to the main shaft rotation direction. The thread design direction is opposite to the rotation direction, that is, the relative friction force between the shaft rotation and the bolt can tighten the bolt; the main shaft bolt 4 is provided with a chamfered corner.

[0034] As an implementation method of this embodiment, the secondary blades 3 and the main shaft bolts 4 are fixed by welding.

[0035] The implementation methods of the present invention are described in detail above, but the present invention is not limited to the described embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalents or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A centrifugal pump impeller with an anti-cavitation function, characterized in that: The invention comprises an impeller body (1), a main shaft (2) and secondary blades (3); the impeller body (1) is connected to one end of the main shaft (2) via a main shaft bolt (4); an opening is provided in the middle of the cavity of the impeller body (1) to form an inlet; the secondary blades (3) are arranged on the main shaft (2) located in the inlet; and the secondary blades (3) are fixed to the main shaft bolts (4).

2. The cavitation-resistant centrifugal pump impeller according to claim 1, characterized in that: The secondary blades (3) are designed as high-efficiency centrifugal blades with a three-dimensional curved surface.

3. The cavitation-resistant centrifugal pump impeller according to claim 1, characterized in that: The secondary blades (3) and the impeller blade rotation direction rotate synchronously with the main shaft (2).

4. The cavitation-resistant centrifugal pump impeller according to claim 1, characterized in that: The number of blades of the secondary blades (3) corresponds to the number of blades of the impeller.

5. The anti-cavitation centrifugal pump impeller according to claim 1, characterized in that: The wrap angle of the secondary blade (3) is set at 30° to 60°.

6. The anti-cavitation centrifugal pump impeller according to claim 1, characterized in that: The spindle bolt (4) is divided into two parts, an upper part and a lower part, the lower part is cylindrical, and the upper part is designed as a regular hexagon.

7. The cavitation-resistant centrifugal pump impeller according to claim 6, characterized in that: The threads on the inner sides of the upper and lower parts of the main shaft bolt (4) are designed identically, and the direction of the screw thread is opposite to the direction of rotation of the main shaft (2).

8. The cavitation-resistant centrifugal pump impeller according to claim 6, characterized in that: The main shaft bolt (4) is provided with a rounded corner.

9. The anti-cavitation centrifugal pump impeller according to claim 1, characterized in that: The secondary blades (3) and the main shaft bolts (4) are fixed together by welding.

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