Five Points Of The Cryostat

1. The temperature control principle of the thermostat?

Answer: It automatically adjusts the heater through the electronic relay. When the temperature of the system is lower than the set value due to the heat spread out, the relay forces the heater to work. When the system reaches the set temperature again, it automatically Stop heating. The heat is evened by a stirrer. The thermostat accurately reflects the temperature value of the temperature-controlled part while controlling the temperature.

2. How many ways can a system be maintained at a constant temperature above room temperature?

Answer: (1) System-environmental ideal adiabatic relationship between environments;

         (2) System-environmental approximate adiabatic dynamics; when the system will continuously and stably dissipate heat to the environment, the environment continuously and stably delivers almost equal amount of heat to the system in another way;

         (3) The relay type temperature control device described in the experimental book.

3. What should I pay attention to when using a Beckman thermometer?

Answer: (1) Do not rotate at will. Beckman thermometer is a more expensive instrument. When using it, be bold and careful, gently handle it and hold it if necessary.

         (2) When adjusting, pay attention to prevent condensation and heat accumulation to prevent the thermometer from bursting.

         (3) The thermometer should be vertical, otherwise the capillary [industrial electrical network-cnelc] tube is easy to break.

         (4) The adjusted thermometer must be placed on the thermometer holder. Do not connect the mercury column in the capillary to the mercury in the tank. Otherwise, it must be readjusted.

4. How to improve the sensitivity of the bath?

Answer: (1) Constant temperature medium: The medium has good fluidity and large heat capacity, so the sensitivity is high.

         (2) Thermometer: The heat capacity is small, the contact surface with the constant temperature medium is large, the adhesion between the mercury and the platinum wire and the capillary wall is small, and the sensitivity is high.

         (3) Heater: The smaller the heating power, the higher the sensitivity.

         (4) Stirrer: The stirring speed must be large enough to make the temperature of each part of the constant temperature medium as uniform as possible.

         (5) Position of the component: The heater is placed near the agitator to allow heat to be quickly transferred to each part. The thermometer should be placed near the heater and the thermometer for temperature measurement should be placed near the system under study.

5. Is there any special requirement for the temperature and heating voltage of the water in the constant temperature bath? why?

Answer: The temperature of the water in the tank should not be too large compared with the room temperature to reduce the heat dissipation rate to the environment; the heating voltage should not be too small or too large. Otherwise, the heat dissipation rate is too large, the heating speed is too large, and the heating inertia is large, so that the sensitivity is lowered when the temperature is controlled. When the heating voltage is too small, the temperature of the system may be relatively low for a relatively long period of time or may not reach the set temperature.

点击图标下载 App