METHOD FOR AUTOMATIC CONTROL OF DRYING PROCESS IN FREEZE DRIER Russian patent published in 1994 - IPC

FIELD: automatic control systems. SUBSTANCE: residual pressure in a freeze-drying chamber and the product temperature at the outlet of drier 1 are continuously measured, the ratio between the product temperature at the outlet of drier 1 and the temperature of sublimation is determined, and the correction control is provided according to this ratio. When the resultant value differs from the specified value towards reduction the power of the drive of vacuum pump 2 is increased, then the flow rate of the product to be dried in line 6 is decreased, another section of desublimator 5 is energized providing regeneration of the previous one. When the ratio differs towards increase the flow rate of the product to be dried in line 6 is increased, then the power of the drive of vacuum pump 2 is decreased. The drive power is increased either until the specified value of the ratio between the product temperature and the temperature of sublimation is reached at restrictions on the temperature of sublimation or up to the maximum value of the drive power. The flow rate of the product in line 5 is decreased either until the specified value of the ratio between the product temperature and the temperature of sublimation is reached at restrictions on the temperature of sublimation or up to minimum specified value of the product flow rate in line 6 and by energizing a new section of desublimator 5. The product flow rate increase in line 6 is provided either until the specified value of the ratio between the product temperature and the temperature of sublimation is reached at restrictions on the product temperature or up to maximum value of filling of drier 1. The power of the drive of vacuum pump 2 is decreased until the specified value of the ratio between the product temperature and the temperature of sublimation is reached at restrictions on the product temperature. EFFECT: improved efficiency. 2 cl, 1 dwg