Classification of Yingtai Centrifuge Rotors

Classification of Yingtai Centrifuge Rotors

The centrifuge rotor (also called the rotating head) is the core component of a centrifuge for sample separation. Its speed is determined by the material and strength of the rotor. To achieve optimal separation, selecting the appropriate rotor is crucial. Centrifuge rotors generally fall into two main types: fixed-angle rotors and swing-out rotors (horizontal rotors).  

1. Fixed-Angle Rotor

In a fixed-angle rotor, the angle between the centrifuge tube and the rotation axis remains constant during centrifugation, typically between 14° and 45°. During operation, the sample first sediments along the sidewall of the tube and then slides down to collect at the outer bottom.  

Advantages:  

- High sedimentation efficiency  

- Excellent versatility  

- Wide capacity range  

Applications:  

Primarily used for pellet centrifugation of various sample volumes. Fixed-angle rotors are the most widely used type in centrifugation.  

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2. Swing-Out Rotor (Horizontal Rotor)  

Also known as a swinging bucket rotor, this type holds the tubes parallel to the rotation axis when at rest. As the rotor accelerates, the tubes swing outward to a 90° angle relative to the axis.  

Characteristics:  

- Mainly used for density gradient centrifugation.  

- Particles travel a longer distance, leading to longer centrifugation times.  

- The relative positions of components in the solution remain unchanged during and after centrifugation, ensuring high separation resolution.  

- Unlike fixed-angle rotors, particles move radially outward rather than along parallel paths.  

- Sedimented particles slide down the tube wall, causing minor convection (though less than in fixed-angle rotors).  

- Vibration may occur at low-speed startup or shutdown, potentially affecting separation efficiency.  

Subtypes:  

- Open-Type Swing-Out Rotor:  

  - Typically used for large-volume preparations.  

  - Maximum speed: < 10,000 rpm (centrifugal force < 16,000 × g).  

  - Mainly applied in initial sample separation.  

- Sealed-Type Swing-Out Rotor:  

  - Used for smaller-volume preparations.  

  - Maximum speed: > 10,000 rpm (centrifugal force > 16,000 × g).  

  - Designed to reduce wind resistance, making it suitable for isolating mitochondria, chloroplasts, nuclei, and density gradient centrifugation.  

Additionally, rotors designed for microplate centrifugation can also be classified as swing-out rotors.