Methods for vibration reduction in laboratory centrifuges

Release time:

2012-09-19

Overview:

The centrifuge’s operating speed is kept well away from the critical speed of the rotating system. Passive vibration isolation involves using various types of vibration dampers to isolate potential vibrations from the machine frame and foundation.

　Vibration in laboratory centrifuges is one of the key indicators for assessing their performance. Vibration reduction can be achieved through active and passive methods. Active vibration reduction involves designing the centrifuge in such a way that its operating speed is kept well away from the critical speeds of the rotating system. Passive vibration reduction, on the other hand, uses various types of vibration dampers to isolate potential vibrations from the machine frame and foundation.

　　1. Design the spindle bearing housing in a flexible vibration-damping configuration;

　　2. The spindle and the motor are connected via a flexible coupling;

　　3. The entire drive system is flexibly connected to the frame.

　　Rubber vibration dampers generally meet the vibration-damping requirements of high-speed centrifuges. Given a fixed damper structure, the higher the rubber hardness, the higher the system's critical rotational speed will be. If the hardness of the damper is too low, its strength will fail to meet the requirements and it will easily get damaged.

　　There are two types of shafts used in laboratory high-speed centrifuges. One type has a slender, elongated shaft that is inherently highly flexible, allowing it to automatically self-align. The other type features a thicker, shorter shaft with minimal inherent bending flexibility; however, layered vibration dampers ensure that the system’s operating speed remains above the critical speed, thus maintaining the system’s overall flexibility. Although both types constitute flexible systems, the key difference in operation between the slender flexible shaft and the relatively rigid shaft lies in how they achieve automatic alignment: In the case of the slender flexible shaft, automatic alignment primarily relies on the shaft’s bending, enabling the rotor to rotate around its center of mass. By contrast, the relatively rigid shaft achieves automatic alignment through the relative flexible displacements among various components within the entire rotating system.

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Characteristics of Five Commonly Used Rotor Types for Centrifuges

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The Role of Brushless Motors in Laboratory Centrifuges