Introduction to new technology of centrifuges and installation and use
Introduction to new technology of centrifuge
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 computer-controlled intelligent technology, 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.
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.
3. Display digital technology
The typical expression of analog technology is to twist the knob to select operating parameters (such as speed, temperature and time), and display the data with the pointer 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 centrifuge operation (such as speed, temperature, time, acceleration and deceleration rate files, etc.), keyboard operation input, and displayed by numbers,
Therefore, the error between selecting the operating parameters and the reading number is extremely small. And because it is a programmable operation, a set of operating parameters can be numbered and accessible.
How to use the centrifuge safely
1. Correct installation
(1) Power supply voltage: The voltage fluctuation should meet the national standard within +10%, otherwise some manufacturers' centrifuges cannot 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 centrifuge cover, find the level on the main shaft, and adjust the screwing of the adjusting bolts next to the four casters to find the level. Note that the l feet cannot be lost. 2.2 Loading and finding balance
In the design and manufacture of the centrifuge, the imbalance caused by the machining error of the rotor has been remedy for the dynamic balance test, but all centrifuges have their allowable unbalanced load. In order to compete with other manufacturers for the maximum unbalance limit allowed by the centrifuge, the centrifuge manufacturer should try to give a larger value o. At this larger value, the centrifuge can be operated, but the imbalance force generated at this time The bearing and the bracket are suddenly impacted 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. Clean the water in the centrifuge chamber. The centrifuge is cooled when it is running. It is frosted in the centrifuge chamber due to the moisture of the air. 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, clean up the water, and reinstall the rotor.
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