Basic components of a laboratory freeze-dryer

All freeze-dryers are constructed from the same basic components, even though they may vary greatly in size and appearance. 

A freeze-dryer for food production of tons-per-day capacity (e.g. one for coffee) operates on essentially the same principles as a laboratory freeze-dryer used to prepare grams-per-day amounts of tissue samples for microscopic analysis. 

Basically, a freeze-dryer consists of a port for inserting the product, a drying chamber, a vacuum pump, a condenser, and vacuum and temperature gauges and controls. 

The product insertion port is usually a tray or a manifold where the frozen product is placed for freeze-drying. 

The freeze-dryer is equipped with a mechanical pumping system that removes noncondensable gases. With oil sealed mechanical pumps, one should be careful to operate the dryer so that no hydrocarbon vapours from the pump can backstream into the drying chamber. 

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