How to choose centrifuge

There are many kinds of centrifuges, which are usually classified from the following aspects:
(1) According to the speed, it can be divided into: low-speed centrifuge, high-speed centrifuge and ultra-high-speed centrifuge;
(2) According to the requirements of temperature, it can be divided into: ordinary centrifuge and refrigerated centrifuge;
(3) According to the different rotors, it can be divided into horizontal rotor centrifuges and angle rotor centrifuges;
(4) According to the size of the centrifuge volume, it can also be divided into: floor centrifuge, desktop centrifuge, palm centrifuge, etc;
(5) According to the grade of centrifuge, it can also be divided into ordinary centrifuge and precision centrifuge.
Ordinary centrifuges have few functions and are inaccurate in speed and capacity. For example, the maximum speed of an ordinary centrifuge is 5000 rpm, but the actual speed cannot reach 5000 rpm. Such centrifuges are only suitable for ordinary centrifuging work, such as separation of serum, concentration of urine, etc.
The precision centrifuge has many functions, accurate rotating speed and capacity, and is suitable for some experiments with high requirements for centrifuge, such as PCR experiment, blood component separation (mostly used in blood stations), etc.
Choose ordinary centrifuge, according to the size of the workload, mainly from two aspects of speed and capacity. The following is a detailed introduction to the problems that should be paid attention to when purchasing precision centrifuges:

（1） Speed: according to the maximum speed, centrifuges are divided into low-speed centrifuges (<1 0000 RPM / min), high-speed centrifuges (10000 RPM / min - 30000 RPM / min) and ultra-high speed centrifuges (>30000 RPM / min), each centrifuge has the rated maximum speed, the maximum speed refers to the speed under no-load condition, but the maximum speed varies according to the type of rotor and the size of sample mass.
For example, the rated speed of a centrifuge is 16000 RPM / min, which means that the rotor rotates 16000 times per minute when it is empty. After adding samples, the speed will surely be less than 16000 RPM / min. With different rotors, the maximum speed is also different (one imported centrifuge can be equipped with multiple rotors). The horizontal rotor can reach 15000 RPM / min, but the angular rotor can reach 14000 RPM / min, the specific difference should be consulted in detail with the product sales personnel and the relevant technical personnel of the production plant, so the selection of speed should be careful, the maximum speed of the selected centrifuge should be higher than the target speed. For example: the target speed is 16000 RPM / min, and the maximum speed of the selected centrifuge must be higher than 16000 RPM / min.
(2) Temperature: some samples (such as proteins, cells, etc.) will be damaged in high temperature environment, so it is necessary to choose frozen centrifuge, which has a rated temperature range. When the centrifuge is running at high speed, the heat generated is balanced with the refrigeration system of the centrifuge at a certain temperature (generally, the sample of the frozen centrifuge needs to be kept at 3 ℃ ~ 8 ℃), and the specific amount can be achieved is also related to the rotor. For example, the rated temperature range of a centrifuge is - 10 ℃ ~ 60 ℃, when the horizontal rotor is installed, it can reach about 3 ℃, if it is an angle rotor, it may only reach 7 About ℃. In this regard, it is also necessary to consult product sales personnel and relevant technical personnel of the manufacturer in detail.
(3) Capacity: how many sample tubes need to be centrifuged each time, and how much capacity each sample tube needs, these factors determine the total capacity of a centrifuge. Simply speaking, the total capacity of a centrifuge = the capacity of each centrifuge tube × the number of centrifuge tubes, and the total capacity and workload are matched.
(4) Rotor: the rotor of the centrifuge is mainly divided into two types: the horizontal rotor: the hanging blue is in a horizontal state during operation, which is at a right angle to the rotating shaft; the sample will concentrate on the bottom of the centrifuge tube; the angle rotor: the centrifuge container is at a fixed angle to the rotating shaft; the sample will concentrate on the bottom of the centrifuge tube and the side wall near the bottom. If the sample to be separated is concentrated at the bottom of the centrifuge tube, select the horizontal rotor; if the sample is concentrated at the bottom of the centrifuge tube and the side wall near the bottom, select the angle rotor.
Some special tests or samples need special rotors, such as: large capacity hanging basket (mostly used in blood station), enzyme plate rotor, slide rotor, PCR rotor, test tube frame rotor and capillary rotor. All rotors have fixed specifications, which are combined with the capacity of centrifuge, such as 36 × 5ml angle rotor, which not only determines the type of rotor but also the capacity of centrifuge, so the selection of rotor is very important.
(5) Control system: the high-grade centrifuges are all equipped with microcomputer control systems, which can not only ensure the safe operation of the centrifuges, but also automatically complete the work tasks. Now many centrifuges have better human control system
For example: rotor identification function, safety lock function, fault prompt function, acceleration and deceleration curve, etc. In addition to the above points, pay attention to some details and necessary accessories. The main components of the centrifuge are the motor. The motor is divided into the motor with carbon brush and the motor without carbon brush. The former has been eliminated. Most of the current centrifuges are the motor without carbon brush, and some motors also have the brake function. There are also differences in refrigeration of refrigerated centrifuges. Now the technology of environmental protection is, of course, fluorine-free refrigeration. In addition, the noise should be considered, and the centrifuge with less noise should be selected as far as possible, so as to maintain a comfortable experimental environment. In terms of accessories, we should also be careful. Some experiments need to use special centrifuge tubes (centrifuged toxic samples or samples requiring ultra-high speed centrifugation). Such centrifuge tubes must be equipped with corresponding pipe sleeves to be safer. There are also some special sample containers (irregular sample bottles, blood bags, etc.), these details and accessories should be considered carefully when selecting centrifuges, otherwise normal work cannot be carried out.