1 Introduction to new technology of centrifuge
1.1 Temperature Refrigeration When the rotor rotates at high speed, the air friction generates heat, the rotor temperature rises, and the temperature of the sample in the test tube rises. Because biological samples are sensitive to temperature. It is generally required that the temperature be maintained at 4 ° C in the centrifugation experiment. Without the intelligent technology of computer control, it is impossible to achieve an accuracy of ±1 °C. Therefore, the centrifugal chamber is cooled by a refrigerator to achieve the purpose of cooling the rotor and cooling the temperature of the sample. However, it is extremely difficult to measure the actual temperature of the rotating rotor. At home and abroad, a temperature sensor is disposed near the rotor at the bottom of the centrifugal chamber to measure the rotor temperature indirectly. Here T sample = T cavity + T compensation. The T compensation is in turn related to the type of rotor, the speed and the running time.
1.2 Brushless motor direct drive The centrifuge is rotated by the motor with the rotor at high speed. In the past, the motor was a DC motor with a carbon brush. When the centrifuge was running, the carbon brush was worn, causing sparks, noise and even vibration, and it had a long life. At that time, it was necessary to replace the carbon brush and then operate again. What is more serious is that carbon brush wear brings carbon dust pollution, which not only pollutes the centrifuge, but also pollutes the surrounding environment. This pollution is not suitable for the health industry.
1.3 Display Digital Technology The typical form of analog technology is to twist the knob to select operating parameters (such as speed, temperature and time) and display the data with the hands of the dial. The disadvantage is that the reading value of the selected parameter and the data is interfered by the operator and the person of the reading person, and the control precision is poor. And every time you do this, the repeatability is poor. Although some centrifuges display digital display (such as the value of the knob and digital display), although the reading is improved, the value principle is still analog technology; the typical display form of digital display is user-friendly, keyboard operation, digital display The whole computer control of programmable operation, the core of which is intelligent control, is realized by computer. All parameters required for the operation of the centrifuge (such as speed, temperature, time, acceleration and deceleration rate files, etc.), keyboard operation input, and digital display, so the choice of operating parameters and readings error is minimal. And because it is a programmable operation, a set of operating parameters can be numbered and accessible.
2 How to use the centrifuge safely
2.1 Correct installation (1) Power supply voltage: The voltage fluctuation should meet the national standard within +10%, otherwise some manufacturers' centrifuges will not operate normally. If the voltage fluctuates above this, it is recommended to use a voltage regulator to comply with this grid.
(2) The ground wire should be firmly: the wiring of the power supply of the room should meet the requirements. China is a three-phase four-wire system. The three-phase is the three-phase in industrial power. When three-phase electricity is used, the neutral line is separated from the ground line. More importantly, whether it is three-phase industrial power or not, the general single-phase power is good, and the ground line should be reliable to avoid leakage. The ground wire cannot be connected to the heating pipe or the water pipe.
(3) The ground should be flat and firm: for large centrifuges, the floor should be firm at the installation site to ensure the normal operation of the rotor of the centrifuge, without recessing, and the ground at the installation and fixing should be flat and firm.
(4) Find a good level: find a more accurate small level, open the lid of the centrifuge, find the level on the main shaft, and adjust the level of the adjusting bolts next to the four casters to find the level. Note that one of the feet cannot be lost.
2.2 Loading and Finding Balance When the centrifuge is designed and manufactured, the imbalance caused by the machining error of the rotor has been remedied by the dynamic balance test. However, all centrifuges have the allowable unloading amount. Centrifuge manufacturers compete with other manufacturers for the large unbalance limit allowed by the centrifuge, and try to give a larger value. At this larger value, the centrifuge can be operated, but the imbalance force generated at this time suddenly hits the bearing and the bracket at n times per minute, and the centrifuge is damaged. Therefore, users should try to find a good balance and centrifuge for those expensive centrifuges, which is good for the life of the centrifuge.
2.3 Cleaning up the water in the centrifuge chamber When the centrifuge is running, it uses refrigeration. Because of the moisture of the air, it freezes in the centrifuge chamber and freezes to water after shutdown. Most foreign low-speed large-capacity centrifuges have no drainage holes, and the water in the centrifugal chamber is more and more accumulated. At this point, the user should remove the rotor and clean up the accumulated water. When reinstalling the rotor, be sure to install it to avoid accidents.
2.4 Aluminum alloy can not be corroded The centrifuge rotor is generally made of aluminum alloy. When it is corroded, the strength is reduced and it is easy to accident. The aluminum alloy is susceptible to liquid corrosion. After cleaning, it is blown dry with a hair dryer, or inverted for a period of time to confirm that it can be used. Some blood stations imported centrifuges, and there should be 6 plastic trays in 6 aluminum cups. The plastic tray should be placed in a blood bag to avoid direct placement in the aluminum cup. Note the test tube for cracks. If the test tube (especially the test tube used repeatedly) has cracks, it must not be used. Otherwise, the test tube rupture will cause the rotor to lose its balance during rotation, which may cause a vicious accident such as broken shaft.
2.5 Broken shaft accident The rotor is not placed well, or the sample unbalance is too large, and the centrifuge starts. Modern imported centrifuges have unbalanced protection, that is, when the unbalance amount exceeds a certain limit, the power should be automatically cut off to stop the centrifuge. However, under the above circumstances, it is already late, and a serious accident will occur. One of the malignant accidents is the broken shaft. Due to the sudden breaking of the shaft during high-speed rotation, the centrifugal rotor has no support, and the centrifugal machine is turned into a chaotic collision, which can make the centrifuge rotate the machine to a 270° angle. At this time, if there are people or equipment next to it, it will cause casualties and damage to the equipment.
Antibiotic: A drug used to treat bacterial infections. Antibiotics have no effect on viral infections. Originally, an antibiotic was a substance produced by one microorganism that selectively inhibits the growth of another. Synthetic antibiotics, usually chemically related to natural antibiotics, have since been produced that accomplish comparable tasks.
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