Refrigerant is the working medium in the refrigeration […]
Refrigerant is the working medium in the refrigeration system of Lyophilization Equipment , which is a special kind of liquid with low boiling point, so it is easy to evaporate at low temperature, when it absorbs the surrounding heat during evaporation, the temperature of surrounding objects is lowered Then, the vapor of the liquid is compressed into a high-temperature, high-pressure vapor, which is cooled in the condenser to become a liquid, and then the liquid is depressurized and throttled to absorb heat in the evaporator, so that the temperature of the evaporation portion can be made. Continuously reducing the refrigerant moves the heat from one object to another to achieve a cooling process.
The nature of the refrigerant is directly related to the refrigeration effect, economy, safety and operation management of the refrigeration unit. Therefore, the understanding of the refrigerant property requirements cannot be ignored. For the normal operation of the refrigeration system and to improve efficiency, the following requirements are imposed on the refrigerant of lyophilization equipment:
1.High critical temperature and a low condensing pressure;
2. The latent heat of vaporization and thermal conductivity of the liquid should be large. The specific volume of steam should be small.
3. The boiling point and freezing point are low
4. Density and viscosity, and the adiabatic index should be small.
5. Strong chemical stability, no chemical reaction with lubricant, no corrosive effect on machinery.
6. Harmless to the human body, non-flammable and explosive
7. Low price
Commonly used refrigerants include: ammonia (R717, Freon 12 (R12, Freon 13 (R13, Freon 22 (R22, azeotropic refrigerant R500, azeotropic refrigerant R502, azeotropic refrigerant R503, etc.).
In addition, the brine is an intermediate medium in the Lyophilization Equipment, also known as the second refrigerant, which is mainly used for cooling and heating the shelf in the tank, and transmits the absorbed heat to the refrigerant or absorbs the heat source. The heat is transferred to the shelf to provide the amount of cooling required to freeze the product and the sublimation heat of the product to dry. The purpose of using the brine is to make the shelf temperature uniform.