Points to note in the selection of laboratory centrifuges

Rotate speed

Domestic desktop centrifuges are divided into low-speed centrifuges (< 10000rpm/min), high-speed centrifuges (> 10000rpm/min, a 30000rpm/min), and ultra-high-speed centrifuges (>) according to the maximum speed 30,000 rpm/min), each centrifuge has a rated maximum speed.

The maximum speed refers to the speed under no load, but the maximum speed varies depending on the type of rotor and the size of the sample mass. For example, the rated speed of a centrifuge is 16000rpm/min, which means that the rotor rotates 16000 times per minute when it is not loaded, and after adding samples, the speed will definitely be less than 16000rpm/min. Different rotors, the maximum speed is also different, a centrifuge can be equipped with multiple rotors, the centrifuge separation effect mainly depends not on the speed, but on the centrifugal force, so sometimes the speed does not meet the requirements, as long as the centrifugal force can meet the standard is the same, the experiment can achieve the required effect.

Temperature

Some samples (such as proteins, cells, etc.) will be destroyed in a high temperature environment, which requires the choice of refrigerated centrifuges, which have rated temperature ranges. The heat generated by the centrifuge in high-speed operation and the refrigeration system of the centrifuge are balanced at a certain temperature (generally the sample of refrigerated centrifugation needs to be kept at 3 °C ~ 8 °C), the specific amount can be reached is also related to the rotor, such as a centrifuge rated temperature range of -20 °C ~ 40 °C, equipped with a horizontal rotor can reach about 3 °C when rotating, if the angle rotor may reach about 7 °C, the specific situation depends on the set temperature and speed and rotor to decide.

Capacity

How many sample tubes need to be centrifuged each time, how much capacity is needed for each sample tube, these factors determine the total capacity of a centrifuge, simply put, the total capacity of the centrifuge = the capacity of each centrifuge tube× the number of centrifuge tubes, the total capacity and the size of the workload are matched.

Rotor

The rotor of the laboratory centrifuge is mainly divided into two types, the horizontal rotor: the hanging blue and the test tube are in a horizontal state when running, at right angles to the rotating shaft, and the sample will concentrate the precipitation at the bottom of the centrifuge tube. Angle rotor: The centrifuge vessel is at a fixed angle to the rotating shaft, and the sample concentrates the pellet at the bottom of the centrifuge tube and on the side wall near the bottom. Choose a horizontal rotor if you want the separated sample to be concentrated at the bottom of the tube, and an angle rotor if you want the sample to be concentrated on the bottom of the tube and on the sidewall near the bottom. There are also special tests or special samples that require special rotors, such as: large-capacity hanging baskets (mostly used in blood stations), enzyme plate rotors, slide rotors, PCR rotors, tube rack rotors and capillary rotors. The rotor has fixed specifications, it is combined with the capacity of the centrifuge, such as 36×5ml angle rotor, both determine the type of rotor and determine the capacity of the centrifuge, in addition, the rotor material is also divided into engineering plastics, stainless steel, aluminum alloy, titanium alloy and other materials, the difference in material selection directly determines the price, speed and service life of the rotor, so the choice of rotor is very important.

Control system

Benchtop laboratory centrifuges are equipped with microcomputer control systems that not only ensure the safe operation of the centrifuge, but also automate the completion of work tasks. Now many centrifuges have a better humanized control system. For example: rotor recognition function, safety lock function, automatic balancing function, fault prompt function, acceleration and deceleration curve, etc. In addition to the above points, it is necessary to pay attention to some details and necessary accessories.

Motor

The main component of the centrifuge is the motor, the motor is divided into a motor with carbon brush and a motor without a carbon brush, the former due to the shortcomings of toner pollution, noise, the need for regular maintenance and replacement of carbon brushes, etc., has been eliminated, most of the centrifuges are brushless motors, and some motors also have brake functions. Refrigerated centrifuges also differ in terms of refrigeration, and the environmentally friendly technology is of course fluorine-free refrigeration.

In addition, it is also necessary to consider the noise problem, try to choose a centrifuge with less noise, so as to maintain a comfortable experimental environment. Some laboratory centrifuges use special centrifuge tubes (centrifuge toxic samples or samples that require ultra-high-speed centrifugation), which must be equipped with corresponding sleeves to be safer. There are also special sample containers (irregular vials, blood bags, etc.), these details and accessories must be carefully considered when choosing a centrifuge, otherwise normal work will not be possible.