Maintaining a controlled vacuum is essential for lowering the boiling point of the solvent and allowing sublimation to occur at low temperatures.
The vacuum system typically consists of a series of pumps, including rotary vane pumps or dry pumps, which work in tandem to evacuate the air and non-condensable gases from the system. Precise pressure control is often achieved through the bleed-in of inert gases, such as nitrogen, which allows the system to maintain a specific "set point" rather than simply pulling the lowest possible vacuum. This controlled environment ensures that the rate of heat transfer is optimized, preventing the product from overheating while ensuring the drying process proceeds at an efficient pace.
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