A dynamic balancing test device for impellers

Abstract

This application relates to the field of impeller testing equipment technology, and more particularly to an impeller dynamic balancing testing device, which includes a vacuum testing chamber with a sealed door on its side wall. Inside the vacuum testing chamber are air-bearing seats for clamping the impeller, with one air-bearing seat on each side of the bottom of the chamber. A drive assembly for driving the impeller to a target speed is also located inside the vacuum testing chamber. A testing port is opened at the top of the vacuum testing chamber, and a mounting frame is connected to the chamber. A laser Doppler vibration meter for radial measurement of the impeller is mounted on the mounting frame, corresponding to the testing port. A capacitive displacement probe for monitoring the axial movement of the impeller is also installed on the vacuum testing chamber. Both the laser Doppler vibration meter and the capacitive displacement probe are externally connected to a testing terminal. This application addresses the problems of long testing cycles, low efficiency, and complex operation inherent in traditional impeller testing technology.

Description

Technical Field

[0001] This utility model relates to the field of impeller testing equipment technology, and in particular to an impeller dynamic balancing testing device. Background Technology

[0002] Molecular pumps are used to evacuate containers and belong to the field of vacuum equipment technology. Their working principle is to use a high-speed rotating impeller to extract gas from the container cavity and directionally extract gas molecules from the cavity, thereby obtaining the required high vacuum environment.

[0003] Molecular pumps require high impeller speeds, typically above 20,000 rpm. Because the impeller operates at high speed, vibrations caused by impeller imbalance directly affect the pump's performance. In severe cases, the pump may fail to reach its operating speed during startup or even be damaged. Therefore, the impeller must undergo rigorous testing before installation, especially strict dynamic balancing, with a dynamic balancing accuracy generally needing to reach G0.4 or higher.

[0004] Current technology involves performing offline dynamic balancing on a conventional dynamic balancing machine before the impeller is assembled into the molecular pump. This aims to control the impeller imbalance within a certain range. However, conventional dynamic balancing machines typically operate at speeds below 3000 rpm. After offline dynamic balancing, the impeller is then assembled into the molecular pump, and online dynamic balancing is performed at high speeds using a high-precision dynamic balancing instrument to ensure the impeller's dynamic balancing accuracy at high speeds. Existing testing techniques are time-consuming, inefficient, and complex to operate. In particular, online dynamic balancing requires disassembling the pump casing, which can easily damage the control circuitry and is detrimental to the mass production of molecular pumps. Utility Model Content

[0005] To address the issues of long testing cycles, low efficiency, and complex operation in impeller testing technology, this application provides an impeller dynamic balancing testing device.

[0006] The impeller dynamic balancing testing device provided in this application adopts the following technical solution:

[0007] A dynamic balancing testing device for an impeller includes a vacuum testing chamber with a sealed door on its side wall. An air-bearing housing for clamping the impeller is located inside the chamber, with one air-bearing housing on each side of the bottom of the chamber. A drive assembly for driving the impeller to a target rotational speed is also located inside the chamber. A testing port is provided on the top of the chamber, and a mounting frame is connected to the chamber. A laser Doppler vibration meter for radial measurement of the impeller is mounted on the mounting frame, corresponding to the testing port. A capacitive displacement probe for monitoring the axial movement of the impeller is also provided on the chamber. Both the laser Doppler vibration meter and the capacitive displacement probe are externally connected to a testing terminal.

[0008] Preferably, the drive assembly includes an annular frame and a pneumatic turbine driver. The annular frame is installed on the top of the vacuum testing chamber and is located between two air bearing seats. The pneumatic turbine driver is installed on the annular frame and several pneumatic turbine drivers are evenly arranged along the length of the annular frame. The pneumatic turbine driver is electrically connected to the testing terminal.

[0009] Preferably, the pneumatic turbine driver is inclined at a 15° acute angle toward the edge of the impeller blade, and the pneumatic turbine driver is a non-diffusion jet.

[0010] Preferably, three detection ports are equidistantly arranged along the length of the vacuum detection box, and the three detection ports cover the length of the impeller.

[0011] Preferably, the vacuum testing chamber has a negative pressure port at the bottom, and a porous titanium alloy recovery plate is connected to the negative pressure port. The diameter of the holes on the porous titanium alloy recovery plate (12) is 0.1 mm. A gas collection hood is connected below the negative pressure port. The gas collection hood is connected to a high-speed vortex dry pump through a pipe. The pumping speed of the high-speed vortex dry pump is 500 L / s.

[0012] Preferably, the detection port is provided with pressure-resistant quartz glass.

[0013] In summary, this application includes the following beneficial technical effects:

[0014] This utility model provides an impeller dynamic balancing testing device that uses multiple sets of laser Doppler vibration meters to measure the entire length of the impeller. Combined with an axial capacitance probe, it achieves simultaneous monitoring of radial and axial vibrations, improving the accuracy of impeller dynamic balancing testing. The non-contact measurement avoids interference with the impeller's rotation state, further enhancing the testing accuracy. Furthermore, the impeller is driven to speeds greater than 20,000 rpm in a vacuum testing chamber by a pneumatic turbine driver, completely simulating the working environment of a molecular pump. This solves the problem of inaccurate results at low speeds, thus improving the long cycle time, low efficiency, and complex operation of existing impeller testing technologies.

[0015] This utility model provides an impeller dynamic balancing test device that uses a pneumatic turbine driver to precisely drive the impeller edge with non-diffusion injection. Combined with a bottom porous titanium alloy recovery plate and a 500L / s high-speed vortex dry pump, it realizes the guided recovery of gas in the vacuum test chamber and ensures that the vacuum degree in the vacuum test chamber is maintained while blowing high-pressure gas. During this period, the impeller speed loss is less than 0.02%. Attached Figure Description

[0016] Figure 1 This is a first-view view of the impeller dynamic balancing test device in the embodiments of this application;

[0017] Figure 2 This is a second-view view of the impeller dynamic balancing test device in the embodiments of this application;

[0018] Figure 3 This is a schematic diagram illustrating the internal structure of the vacuum testing chamber in the embodiments of this application.

[0019] Explanation of reference numerals in the attached drawings: 1. Vacuum detection chamber; 11. Sealed door; 12. Porous titanium alloy recovery plate; 13. Gas collection hood; 2. Air bearing seat; 3. Drive assembly; 31. Ring frame; 32. Pneumatic turbine driver; 4. Fixing frame; 41. Laser Doppler vibration meter; 5. Capacitive displacement probe; 6. High-speed vortex dry pump; 7. Pressure-resistant quartz glass. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0021] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation or specific orientation structure and operation, and therefore should not be construed as a limitation of this utility model; the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In addition, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0022] This application discloses an impeller dynamic balancing testing device. (Refer to...) Figure 1 , Figure 2 and Figure 3 The impeller dynamic balancing test device includes a vacuum testing chamber 1, with a sealed door 11 on the side wall of the vacuum testing chamber 1. An air bearing seat 2 for clamping the impeller is installed inside the vacuum testing chamber 1. One air bearing seat 2 is located on each side of the bottom of the vacuum testing chamber 1. The air bearing seat 2 reduces friction and noise by providing non-mechanical contact support. A drive assembly 3 for driving the impeller to the target speed is installed inside the vacuum testing chamber 1. A testing port is opened on the top of the vacuum testing chamber 1. A fixing frame 4 is connected to the vacuum testing chamber 1. A laser Doppler vibration meter 41 for radial measurement of the impeller is installed on the fixing frame 4, corresponding to the testing port. A capacitive displacement probe 5 for monitoring the axial movement of the impeller is also installed on the vacuum testing chamber 1. Both the laser Doppler vibration meter 41 and the capacitive displacement probe 5 are externally connected to the testing terminal.

[0023] By using multiple sets of laser Doppler vibration meters 41 to measure the entire length of the impeller, combined with an axial capacitance probe, synchronous monitoring of radial and axial vibration is achieved, improving the accuracy of dynamic balance testing of the impeller. Non-contact measurement avoids interference with the impeller's rotation state, further improving the testing accuracy. Furthermore, the impeller is driven to speeds greater than 20,000 rpm by a pneumatic turbine driver 32 in a vacuum testing chamber 1, completely simulating the working environment of a molecular pump, thus solving the problem of inaccurate dynamic balance results at low speeds. This achieves the effect of improving the problems of long cycle time, low efficiency, and complex operation in impeller testing technology.

[0024] The drive assembly 3 includes an annular frame 31 and a pneumatic turbine driver 32. The annular frame 31 is installed on the top inside the vacuum detection chamber 1 and is located between two air bearing seats 2. The pneumatic turbine driver 32 is installed on the annular frame 31 and several pneumatic turbine drivers 32 are evenly arranged along the length of the annular frame 31. The pneumatic turbine driver 32 is electrically connected to the detection terminal.

[0025] The pneumatic turbine driver 32 is inclined at a 15° acute angle toward the edge of the impeller blade, and the pneumatic turbine driver 32 is a non-diffusion jet.

[0026] There are three detection ports arranged at equal intervals along the length of the vacuum detection box 1, and the three detection ports cover the length of the impeller.

[0027] The vacuum testing chamber 1 has a negative pressure port at the bottom, and a porous titanium alloy recovery plate 12 is connected to the negative pressure port. The diameter of the holes on the porous titanium alloy recovery plate 12 is 0.1mm. A gas collection hood 13 is connected below the negative pressure port. The gas collection hood 13 is connected to a high-speed vortex dry pump 6 through a pipe. The pumping speed of the high-speed vortex dry pump 6 is 500L / s.

[0028] The impeller edge is precisely driven by a non-diffusion jet from a pneumatic turbine driver 32, combined with a bottom porous titanium alloy recovery plate 12 and a 500L / s high-speed vortex dry pump 6, to achieve gas guidance and recovery in the vacuum detection chamber 1. While blowing high-pressure gas, the vacuum level in the vacuum detection chamber 1 is maintained. During this period, the impeller speed loss is less than 0.02% (only 8 rpm fluctuation at 40,000 rpm in actual measurement).

[0029] The detection port is equipped with pressure-resistant quartz glass 7, which has a light transmittance of more than 99.7%, allowing the laser signal of the laser Doppler vibration meter 41 to pass through, and has a compressive strength of 0.5 MPa.

[0030] The implementation principle of the impeller dynamic balancing test device in this application embodiment is as follows: First, open the sealed chamber door 11 and install the impeller horizontally between two air bearing seats 2. Then, close the sealed chamber door 11 and use a vacuum pumping device to evacuate the vacuum test chamber 1 to a preset vacuum level. Start the annular pneumatic turbine driver 32 and spray high-pressure nitrogen gas at a 15° acute angle to the edge of the impeller blades. Accelerate to the target speed (e.g., 4000 rpm) within 60 seconds. At the same time, start the high-speed vortex dry pump 6 to maintain the vacuum level in the vacuum test chamber 1. Then, multiple sets of laser Doppler vibration meters 41 scan the entire length of the impeller through the pressure-resistant quartz glass 7 to generate a three-dimensional vibration cloud map. The capacitive displacement probe 5 monitors the axial displacement of the impeller in real time (sampling rate 1MHz). Finally, the test terminal generates an electronic test report (including the balance level G value and spectrum analysis diagram).

[0031] The air bearing housing 2 needs to be cleaned after each use.

[0032] Finally, it should be noted that the above description is only a preferred embodiment of this utility model, and the protection scope of this utility model is not limited to the above embodiments. All technical solutions within the scope of this utility model's concept are within the protection scope of this utility model. It should be pointed out that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A device for dynamic balancing of an impeller, characterized in that: The system includes a vacuum testing chamber (1), a sealed door (11) on the side wall of the vacuum testing chamber (1), an air bearing seat (2) for clamping the impeller inside the vacuum testing chamber (1), an air bearing seat (2) on each side of the bottom of the vacuum testing chamber (1), a drive assembly (3) for driving the impeller to the target speed inside the vacuum testing chamber (1), a testing port on the top of the vacuum testing chamber (1), a fixed frame (4) connected to the vacuum testing chamber (1), a laser Doppler vibration meter (41) for measuring the radial direction of the impeller installed on the fixed frame (4), the laser Doppler vibration meter (41) corresponding to the testing port, and a capacitive displacement probe (5) for monitoring the axial movement of the impeller on the vacuum testing chamber (1). Both the laser Doppler vibration meter (41) and the capacitive displacement probe (5) are externally connected to the testing terminal.

2. The impeller dynamic balancing testing device according to claim 1, characterized in that: The drive assembly (3) includes an annular frame (31) and a pneumatic turbine driver (32). The annular frame (31) is installed on the top of the vacuum testing chamber (1) and is located between two air bearing seats (2). The pneumatic turbine driver (32) is installed on the annular frame (31) and several pneumatic turbine drivers (32) are evenly arranged along the length of the annular frame (31). The pneumatic turbine driver (32) is electrically connected to the testing terminal.

3. The impeller dynamic balancing testing device according to claim 2, characterized in that: The pneumatic turbine driver (32) is inclined at a 15° acute angle toward the edge of the impeller blade, and the pneumatic turbine driver (32) is a non-diffusion jet.

4. The impeller dynamic balancing testing device according to claim 1, characterized in that: The detection ports are arranged at equal intervals along the length of the vacuum detection box (1), and the three detection ports cover the length of the impeller.

5. The impeller dynamic balancing testing device according to claim 1, characterized in that: The vacuum testing box (1) has a negative pressure port at the bottom. A porous titanium alloy recovery plate (12) is connected to the negative pressure port. The diameter of the holes on the porous titanium alloy recovery plate (12) is 0.1 mm. A gas collection hood (13) is connected below the negative pressure port. The gas collection hood (13) is connected to a high-speed vortex dry pump (6) through a pipe. The pumping speed of the high-speed vortex dry pump (6) is 500 L / s.

6. The impeller dynamic balancing testing device according to claim 1, characterized in that: The testing port is equipped with pressure-resistant quartz glass (7).

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