1 Introduction to the new technology of centrifuge
1.1 Temperature cooling
When the rotor rotates at a high speed, air friction generates heat, the temperature of the rotor will rise, and the temperature of the sample in the test tube will also rise. Because biological samples are sensitive to temperature. It is generally required that the temperature be maintained at 4°C during the centrifugal experiment. Without computer-controlled intelligent technology, it is impossible to achieve an accuracy of ±l°C. Therefore, a refrigerator is used to cool the centrifugal cavity to achieve the purpose of cooling the rotor and cooling the sample temperature. However, it is extremely difficult to measure the actual temperature of the rotating rotor. At home and abroad, temperature sensors are installed at the bottom of the centrifugal cavity closer to the rotor to indirectly measure the temperature of the rotor. Here T sample = T cavity + T compensation. T compensation is related to the type, speed and running time of the rotor.
1.2 Direct drive by brushless motor
The centrifuge is rotated at a high speed by a motor with a rotor. In the past, the motor was a DC motor with carbon brushes. When the centrifuge was running, the carbon brushes were worn out, causing sparks, noise and even vibration, and they had a long life. The carbon brushes should be replaced at that time and the universal operation can be performed. What's more serious is the pollution of carbon dust caused by the wear of carbon brushes, which not only pollutes the centrifuge, but also pollutes the surrounding environment. This kind of pollution is not suitable for the sanitation industry.
1.3 Display digital technology
The typical form of analog technology is to turn the knob to select operating parameters (such as speed, temperature and time, etc.), and display the data with the pointer of the dial. The disadvantage is that the reading value of the selected parameter and data is interfered much by the operator and the reading person, and the control accuracy is poor. And every operation has to be like this, and the repeatability is poor. Although some centrifuges have digital display (such as knob selection and digital display), although the reading has been improved, the principle of the value has not changed and is still analog technology; the typical form of digital display is friendly interface, keyboard operation, and digital display , Programmable full computer control, the core of which is intelligent control, which is realized by a computer. All parameters needed for centrifuge operation (such as speed, temperature, time, acceleration and deceleration rate files, etc.), input by keyboard operation, and displayed in numbers,
Therefore, the error between the selection of operating parameters and the number of readings is extremely small. Also, because it is a programmable operation, a group of operating parameters can be coded into numbers, which can be accessed and used.
2 How to use the centrifuge safely
2.1 Correct installation
(1) Power supply voltage: The voltage fluctuation must meet the national standard within +l0%, otherwise the centrifuges of some manufacturers will not operate normally. If the voltage fluctuates above this, it is recommended to use a voltage stabilizer to meet this grid.
(2) The ground wire must be firm: the wiring of the power supply in the room must meet the requirements. Our country is a three-phase four-wire system. Three-phase is the three-phase of industrial electricity. When using three-phase electricity, the neutral wire is separated from the ground wire. More importantly, whether it is three-phase industrial electricity or general single-phase electricity, the ground wire should be reliable to avoid leakage. , The ground wire cannot be connected to the heating pipe or water pipe.
(3) The ground should be flat and firm: For large centrifuges, the floor should be firm when moving at the installation site to ensure that the centrifuge rotor works normally without sinking in. The ground at the installation location 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, find the level by adjusting the adjustment bolts beside the 4 casters, and pay attention to the l feet of the level.
2.2 Loading samples to find balance
During the design and manufacture of the centrifuge, the imbalance caused by the machining error of the rotor has been remedied by the dynamic balance test. However, all centrifuges have their allowable imbalance in sample loading. In order to compete with other manufacturers on the index of the maximum allowable imbalance limit of the centrifuge, the centrifuge manufacturer tries to give a larger value o, at which the centrifuge can run, but the imbalance force generated at this time Suddenly impacting the bearing and the support at a frequency of n times per minute, the centrifuge is damaged. Therefore, for those expensive centrifuges, users should try their best to find a balance and centrifuge, which is beneficial to the life of the centrifuge.
2.3 Cleaning the water in the centrifugal cavity When the centrifuge is running, refrigeration is used. Due to the moisture in the air, frost forms in the centrifugal cavity, and the frost turns into water after shutdown. Most foreign low-speed large-capacity centrifuges have no drainage holes, and the more water accumulates in the centrifuge chamber. At this time, the user should remove the rotor by himself to clean up the stagnant water. Reinstall the rotor