Freeze dryer system
The freeze dryer system is assembled by manufacturers to preserve perishable materials, which are widely used in bioengineering, pharmaceutical industry, food industry, materials science, and deep processing of agricultural and sideline products. The process of freeze dryer system is which water is frozen, followed by its removal from the product, initially by sublimation (primary drying) and then by desorption (secondary drying). It is a freeze drying process applicable to manufacture of certain pharmaceuticals and biological products that are unstable in aqueous solutions for prolonged storage periods, but that are stable in the dry state.
Freeze dryer system is consisted of: refrigeration system, vacuum system, heating system and control system, as well as the auxiliary components like temperature probes, vacuum sensors pressure gauges and so on. The refrigeration system is the most important part of the freeze dryer system and is called the heart of the freeze dryer. Usually, the refrigeration system is composed of refrigeration compressor, condenser, evaporator, thermal expansion valves and solenoid valves. The compressor mainly compresses gaseous refrigerant, sucks in low-temperature and low-pressure gaseous refrigerant from the suction port, after being compressed by the compressor, it becomes high temperature and high-pressure gaseous refrigerant, which is discharged through the exhaust pipe. Usually, the quick-freezing refrigeration system and the water trap refrigeration system share a set of refrigeration system. The vacuum system consists of vacuum pumps and roots pumps.
The vacuum level of the freeze dryer system should match the sublimation temperature of the product and the temperature of the condenser. If the vacuum is level too high or too low, it is not conducive to sublimation. The vacuum level in the drying box of freeze dryer system should be controlled within the set range. Its function is to shorten the sublimation cycle of the product. The heating system mainly consists of circulating pump, heating tubes, plate heat exchanger, liquid storage tank and auxiliary equipment. The function of the system is to heat the materials in the drying chamber so that the materials are continuously heated and sublimated. The electrical control system is composed of PLC, touch screen, control cabinet, control instrument, regulating instrument and other automatic devices and circuits. Its function is to control the freeze dryer system and control the normal operation of the equipment manually or automatically.
In addition to defrosting the condenser and cleaning the freeze dryer system after each cycle, routine freeze dryer maintenance typically includes periodic changing of vacuum pump oil and visually checking all seals and gaskets. Advanced controllers offer the capability of running a periodic system test or leak test to ensure that the freeze dryer system is performing to original factory specifications.