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How to deal with the slowdown of laboratory centrifuge speed

2019/4/12 12:00:49      click :

  The problem often encountered in the use of laboratory centrifuges is that the speed is slowed down, which may be fatal for some primary users, because in many cases, the customer does not know how to deal with the first time, so only, do it urgently, with The degree of influence of the product on production or work, and a series of contradictions, this time has missed the best time to deal with the problem, so Xiaobian here suggests that the use of laboratory centrifuge must be the first time to obtain Contact the merchant. Do not disassemble it yourself, otherwise it may cause more serious consequences, so please keep in mind the new and old customers.
  Laboratory centrifuge density gradient centrifugation is further divided into rate zone centrifugation and iso-density zone centrifugation. The sample is subjected to centrifugal sedimentation or sedimentation equilibrium in a certain inert gradient medium, and the particles are distributed to certain specific positions in the gradient liquid under a certain centrifugal force to form a separation method of different zones. A method of centrifugally centrifuging particles having different sedimentation rates using different centrifugal speeds and centrifugation times is called differential centrifugation. The suspension containing two different particles is centrifuged at a constant speed to sink the large particles, the supernatant is poured into another centrifuge tube, the centrifugal force is increased, and the small particles are separated by centrifugation for a certain period of time. Separate multiple times to achieve separation. Differential centrifugation is mainly used to separate particles with large differences in size and density.

Laboratory centrifuge picture


  If the laboratory centrifuge process is in progress, the motor speed may be too slow, and the brush emits a large spark. What should be done in this case. Analysis and overhaul: This fault is caused by dirt or carbon spring between the motor carbon brush and the commutator, which reduces the elastic force of the carbon brush and the commutator. Solution: Disassemble the machine, unscrew the brush cover, remove the carbon brush with spring, first clean the spring, carbon brush and dirt on the commutator with anhydrous alcohol. If the front end of the carbon brush is broken, it can be used. Assorted enamel and sandpaper are used to grind the carbon brush to the smooth curved contact surface, which makes it fit well with the circular commutator. Then adjust the spring force of the spring appropriately.
  The laboratory centrifuge power indicator and the instrument are normal. Press the start button and the laboratory centrifuge does not run. Repair and treatment: Check the control circuit for no faults, replace the carbon brush in the laboratory centrifuge, and the machine can resume normal operation. This phenomenon is often encountered because the carbon brush is exhausted. Transformer B, burned, the whole machine can't work. Maintenance and treatment: Transformer B primary is 380V, secondary has three sets of output voltage are 220V, 150V, 160V. The contacts of CJ1 and CJ2 are connected in series with the secondary winding (0~150)V of B, and CJ1 and CJ2 are interlocking contacts. B. Burned, check the contacts of CJ1 and CJ2, in which the contacts of CJ1 are burned together and CJ1 is damaged. Replace the CJ and B laboratory centrifuges to return to normal. The cause of the failure is that the starting current is too large, causing C J1 to burn out. The laboratory centrifuge can run at a maximum speed of 2500r/min, which does not meet the working requirements. Repair and treatment: Check that the speed control resistor W W is adjustable and there is no damage. Measuring the conduction voltage Ug of the thyristor SCR and SCR2, the Ug voltage is adjustable to 7V, which is normal. Measuring the conduction of SCR and SCR: is forward conduction, reverse cut-off, and the surface looks normal, but the SCR is replaced: the speed of the laboratory centrifuge can be adjusted to 3 200r/min. The reason for the analysis is the parameter variation of SCR2. The laboratory laboratory centrifuge is driven by a motor through one of the drums. The speed of the centrifuge can affect the separation of the laboratory centrifuge. The following describes how to optimize the control of the laboratory centrifuge:
  Because the motors used in laboratory centrifuges are typically series-excited motors. It consists of two parts, the stator and the rotor. The stator is a concentrated fixed magnetic pole composed of a core and a field coil. The rotor is composed of a core and a rotor coil and a commutator. The laboratory centrifuge is to use the powerful centrifugal force generated by the high-speed rotation of the rotor to accelerate the sedimentation speed of the particles in the liquid, and separate the sedimentation coefficient and the buoyant density of the sample. When the suspension containing fine particles is left stationary, the suspended particles gradually sink due to the action of the gravitational field. The heavier the particles, the faster the sinking, whereas the particles with a lower density than the liquid will float. The rate at which particles move under the gravitational field is related to the size, morphology, and density of the particles, and is related to the strength of the gravitational field and the viscosity of the liquid. Particles of the size of red blood cells, a few micrometers in diameter, can be observed under normal gravity. Finally, using laboratory centrifuges, we need to determine the type and specifications according to the throughput and automation requirements of the operation, so that it is easier to get the results we want.
  The details of the use of laboratory centrifuges are mainly the above, but they are handled properly. It will not have a big impact!