What do I need to prepare for the purchase of a high-speed refrigerated centrifuge

What do I need to prepare for the purchase of a high-speed refrigerated centrifuge

The high-speed refrigerated centrifuge plays an important role in the collection of microorganisms, cell debris, cells, large organelles, sulfuric acid precipitates, and immunoprecipitates. However, if you want to buy a good high-speed refrigerated centrifuge, you need to do a lot of preliminary work. , Such as detailed understanding of centrifuges, familiarity and consultation with manufacturers, search and collection of various materials, etc. What I want to say to you is that if you choose a reliable high-speed refrigerated centrifuge manufacturer, you can often get twice the result with half the effort and bring you more convenience.

The function of the high-speed refrigerated centrifuge when it rotates forward is to make the intracellular streamline tend to be close to the direction of the boundary, which has an important effect on the stability of the flow, and the temperature pulsation is reduced. When the second-hand high-speed refrigerated centrifuge is reversed, the effect is Squeeze the vortex toward the center, which will cause the vortex to become more unstable, and the temperature fluctuation will increase the concentration of impurities in the crystal during the crystal growth process. Obviously, severe temperature fluctuations will cause uneven distribution of impurities in the crystal, and impurity stripes appear. If the direction of rotation of the second-hand high-speed refrigerated centrifuge is the same as the direction of heat convection in the melt, that is, when the high-temperature end of the melt faces the wind, the temperature pulsation in the melt can be suppressed, which is beneficial to the growth of single crystals without impurity streaks. If the high-speed refrigerated centrifuge rotates in the reverse direction, that is, when the low temperature end of the melt faces the wind, there is a strong temperature pulsation in the melt, which is not conducive to the uniform growth of single crystals.

When the high-speed refrigerated centrifuge is not rotating, as the temperature gradient increases, the temperature in the tin melt changes from no pulsation to periodic pulsation, followed by irregular pulsation, with a significant increase in amplitude. When the temperature gradient is about, the pulsation amplitude is about For example, after the second-hand high-speed refrigerated centrifuge rotates, the forward and reverse rotation of the two rotation modes are improved. Among them is the centrifugal acceleration and the gravitational acceleration, which strengthens the convection in the melt and promotes the heat transfer in the melt. In the process of mass transfer, the measured temperature gradient is reduced but the temperature fluctuation trend is quite different. When the high-speed refrigerated centrifuge rotates forward, a set of temperature fluctuation curves are measured.

　　 The pulsation value is greatly reduced. When the high-speed refrigerated centrifuge reverses, the pulsation amplitude increases as it increases, and at the same time the pulsation frequency also increases. The value at that time is larger than that when the high-speed refrigerated centrifuge is not rotating. Regardless of whether the high-speed refrigerated centrifuge rotates forward or reverse, for the same value, the centrifugal force on the melt is the same, but the direction of the force is opposite, and the unit mass of the melt particles receives force.

　　 Among them, the rotational angular velocity of the second-hand high-speed refrigerated centrifuge is the movement speed of the melt particles, relative to the angular velocity of the high-speed refrigerated centrifuge. The flow of melt in the horizontal boat is mainly caused by the natural convection caused by the horizontal temperature difference, and the flow state is determined by the number. Among them, Xi is the volume expansion coefficient, the length of the boat, and the kinematic viscosity coefficient. When it is relatively small, the melt flows in the melt. When it reaches a certain value, multiple cellular circulations will appear, but the temperature of these cellular flow furnaces remains unchanged. Change, the temperature pulsation at different speeds of the high-speed refrigerated centrifuge is recorded as forward rotation and reverse rotation.

　　 It is reported that the speed of the medical high-speed refrigerated centrifuge generally does not exceed 5000r/min, and a horizontal rotor is sufficient, and it can meet the needs of large capacity. Schools, research institutes and other laboratories use high-speed refrigerated centrifuges. Generally, high-speed refrigerated centrifuges (greater than 5000r/min) and small-capacity corner rotors are required. When choosing a high-speed refrigerated centrifuge, the laboratory can choose high-speed refrigerated centrifuges with different capacities, different speeds, and different temperature controls according to the purpose and needs of the experiment. For example, when you need to centrifuge at room temperature, small amount, and fast, you can use palm-type high-speed refrigerated centrifuges and mini high-speed refrigerated centrifuges; if the rotation speed does not exceed 8000r/min, such as collecting cells during cell culture, you can choose ordinary low-speed high-speed refrigerated centrifuges ; If the required speed is greater than 12000rpm, a high-speed refrigerated centrifuge can be used, such as small amount of plasmid DNA extraction, cDNA extraction experiment, protein extraction, competent preparation, and RNA extraction from plants, the speed needs to be 12000rpm-15000rpm and maintain 4 The high-speed refrigerated centrifuge can meet the requirements in the low-temperature environment.