《How to Choose a Centrifuge？》

Choose a regular centrifuge based on the workload, mainly from two aspects: speed and capacity. The following is a detailed introduction to the issues that should be paid attention to when purchasing precision centrifuges:

1.Speed: Centrifuges are divided into low-speed centrifuges (<10000 rpm/min), high-speed centrifuges (10000 rpm/min to 30000 rpm/min), and ultra high-speed centrifuges (>30000 rpm/min) based on their maximum speed. Each centrifuge has a rated maximum speed, which refers to the speed at no load, but the maximum speed varies depending on the type of rotor and the size of the sample. For example, the rated speed of a centrifuge is 16000 rpm/min, indicating that the rotor rotates 16000 times per minute when unloaded. After adding the sample, the speed will definitely be less than 16000 rpm/min. The maximum speed varies depending on the rotor (an imported centrifuge can be equipped with multiple rotors). The horizontal rotor can reach 15000 rpm/min, but the angle rotor can reach approximately 14000 rpm/min. The specific differences should be consulted with product sales personnel and relevant technical personnel of the production plant. Therefore, the selection of speed should be cautious, and the maximum speed of the selected centrifuge should be higher than the target speed. For example, if the target speed is 16000 rpm/mIn, the maximum speed of the selected centrifuge must be higher than 16000 rpm/min.

2. Temperature: Some samples (such as proteins, cells, etc.) can be damaged in high temperature environments, so it is necessary to choose a refrigerated centrifuge, which has a rated temperature range. The heat generated by the centrifuge during high-speed operation and the refrigeration system of the centrifuge are balanced at a certain temperature (usually the sample for freezing and centrifugation needs to be kept at 3 ℃~8 ℃), and the specific amount that can be reached is also related to the rotor. For example, the rated temperature range of a centrifuge is -10 ℃~60 ℃, and when a horizontal rotor is installed, it can reach about 3 ℃ during rotation, If it is an angle rotor, it may only reach around 7 ℃. This also requires detailed consultation with product sales personnel and relevant technical personnel from the production factory.

3. Capacity: How many sample tubes need to be centrifuged each time? 7. How much capacity is required for each sample tube? 7. These factors determine the total capacity of a centrifuge. Simply put, the total capacity of a centrifuge=the capacity of each centrifuge tube × The number of centrifuge tubes, total capacity, and workload are matched.

4. Rotors: The rotors of centrifuges are mainly divided into two types. Horizontal rotors: When running, the hanging basket is in a horizontal state, at right angles to the rotating shaft. The sample concentrates sediment at the bottom of the centrifuge tube. Angle rotors: The centrifuge container is at a fixed angle to the rotating shaft, and the sample concentrates sediment at the bottom of the centrifuge tube and the side wall near the bottom. If you want the separated sample to be concentrated at the bottom of the centrifuge tube, choose a horizontal rotor. If you want the sample to be concentrated at the bottom of the centrifuge tube and the side wall near the bottom, choose an angle rotor.

There are also some special experiments or samples that require special rotors, such as large capacity hanging baskets (mostly used in blood stations), enzyme labeling plate rotors, slide rotors, PCR rotors, test tube rack rotors, and capillary rotors. The rotor has a fixed specification, which is combined with the capacity of the centrifuge, such as 36 × The 5 ml angle rotor determines both the type of rotor and the capacity of the centrifuge, so the selection of the rotor is very important.

5. Control System: High end centrifuges use microcomputer control systems, which not only ensure the safe operation of the centrifuges but also automatically complete work tasks. Nowadays, many centrifuges have user-friendly control systems, such as rotor recognition function, safety lock function, fault prompt function, acceleration and deceleration curve, and so on. In addition to the above points, attention should also be paid to some details and necessary accessories. The main component of centrifuges is the motor, which is divided into carbon brush motor and brushless motor. The former has been phased out, and most centrifuges nowadays are brushless motors, some of which also have braking function. There are also differences in refrigeration between refrigerated centrifuges, and the current environmentally friendly technology is of course fluorine-free refrigeration. In addition, noise issues should also be considered, and it is recommended to choose a centrifuge with low noise as much as possible to maintain a comfortable experimental environment. In terms of accessories, caution should also be exercised. Some experiments require the use of special centrifuge tubes (such as centrifuging toxic samples or samples that require high-speed centrifugation). Such centrifuge tubes must be equipped with corresponding tube sleeves to be safer. There are also some special sample containers (irregular sample bottles, blood bags, etc.), and these details and accessories should be carefully considered when selecting a centrifuge, otherwise normal operation cannot be carried out.