Vapor collect condenser is one of the key components in a freeze drying system, designed to collect and condense vapors that come from raw product. As per freeze dryer application fields, its temperature can be -25C to -80C.
As known, freeze drying is a water removing process, fundamental is sublimation. Frozen product placed in drying chamber, then reduce drying chamber pressure, when pressure drop to a certain level, the solid water in product starts sublimate: Solid to Gas, skip liquid phase. Since the vapor has to go somewhere, then condenser is created to collect vapor.
The principle of ice condenser is simple: Freezing it.
Inside condenser, a module of stainless steel pipe installed, connect to compressor and enable coolant circulates inside. The vapor flows into condenser and hit ultra-cold coils, will be frozen on coils surface. By this, the water from raw product success removed to condenser.
Temperature and Influences
Typically, pharmaceutical freeze dryer condenser temperature is -60C or lower, food freeze dryer condenser temperature is beyond -35C. This is due to pharmaceutical may have solvents apart from water, which may need a lower temperature to be condensed; while food contains most is water.
So, pharmaceutical freeze dryer condenser temperature, the lower, the better; food freeze dryer condenser temperature, -25C to -45C all is well, too high may not work well, too low can only waste electric.
Water Collect Capacity
Condenser vapor collect capacity is designed refer total shelves area: 1m2 shelf area, condenser capacity should not less than 20kgs. Otherwise, the vapor may be suck into vacuum pump and broke it.
The vapor flows to condenser, need be condensed as soon as possible. Otherwise, it may go to vacuum pump and mixing into vacuum pump oil and cause oil milky. Which means the vacuum pump will reduce efficiency, cannot maintain vacuum environment of drying chamber. The result is freeze drying fail and vacuum pump damage.
Condenser capacity also influence by the cooling energy that compressor provides. So, the refrigeration system should well optimize and deliver cooling energy stably.