Composition of vacuum freeze dryer (Part 2/2)
4. Vacuum system
The vacuum system consists of a multi-stage vacuum pump or a water ring pump and a roots vacuum pump. The roots pump cannot be used alone as a booster pump. You must first enable the vacuum pump or water ring pump to work for a period of time. In the following cases, the roots pump will start automatically. See vacuum pump structure, roots pump structure, etc. The vacuum gauge of the vacuum system can use an electric contact vacuum gauge, which can automatically control the startup of the roots pump according to the pre-selected vacuum value.
5. Refrigeration system
The lyophilizer refrigeration system consists of a refrigeration compressor unit, R22 or R404a refrigerant. Usually, the quick freezing refrigeration system and the water trap refrigeration system of a freeze-drying equipment share a refrigeration system. When the system is working, the shelf temperature can be reduced to -35 ° C in the contact heating mode. When the refrigeration system is in operation, the surface temperature of the condensing coil can reach -35 ～ -65 ℃. Low temperature screw or double-stage piston refrigeration compressors can be used according to customer requirements. Generally, the double-stage piston compressor has better refrigeration effect. Cooling temperature is lower.
6. Electrical control system
The electrical control system of this equipment is composed of PLC, touch screen, control cabinet, control instrument, regulating instrument and other automatic devices and circuits. Its function is to control the lyophilizer manually or automatically to control the normal operation of the equipment.