Benchtop centrifuges are machines that use centrifugal force to separate liquids and solid particles or mixtures of liquids and liquids. It is mainly used to separate solid particles in suspension from liquids. In emulsions, it is possible to separate two liquids with different densities that are insoluble in each other (e.g., separating cream from milk). They can also be used to remove liquids from wet solids, e.g., to throw away wet clothes in a washing machine. Special overdrive tube separators can also separate gas mixtures of different densities. Taking advantage of the fact that solid particles of different densities or particle sizes settle in liquids at different rates, some settling benchtop centrifuges can also classify solid particles according to density or particle size.
But the equipment where the machine is located may occur some failures, some are common failures, the user should pay attention to a lot of use, but also to remember these failures, in the process of machine operation can make a good judgment. Benchtop centrifuges often occur in the failure to see the phenomenon, to analyze the reasons, apply the appropriate maintenance methods in order to solve the problems in use in a timely manner. The following is the analysis of common machine problems:
After the centrifuge is started, the rotor speed reaches about 830r/min, the rotor will have a warning light flashing, the rotor will stop speed and enter.
The main reason for this phenomenon can be seen in the rotor speed detection circuit. For example, the sensor of the rotor pulse generator RBG is faulty. In addition, there is deterioration of characteristics, aging of transistors and reduction of current amplification factor or resistance change value, which can cause this failure.
In order to confirm that the RPGA point pulse signal is about 3Vp-p, the pulse width varies with the speed. In other words, the RPG sensor is working properly with a 2.8Vp-p pulse signal at both the transistor Q4 collector click and the Z32 input. the output of Z32 is a plus or minus 5V DC level, which is normally a 5Vp-p pulse signal. This is because the 2.8Vp-p pulses input when the threshold voltage of Z32 is about 3V keep the inverter from lighting up. This is due to the incorrect detection state being processed at this time and the warning light flashing on the rotor. Confirm again whether the Q4 collector current is lower than normal, if Q4 aging is not serious, then increase the output voltage of Q4 can be. Reduce the collector resistance R31, increase the collector current, so that Q4 reaches saturation conduction, the output collector output is about 5Vp-p pulse information, the machine returns to normal operation.