METHOD OF AUTOMATIC CONTROL OVER A CONTINUOUS PROCESS OF VACUUM FREEZE DRYING Russian patent published in 2004 - IPC

FIELD: methods of vacuum freeze drying.

SUBSTANCE: the invention is dealt with vacuum freeze drying, in particular, with a continuous process of a vacuum - cryodesiccation with extrusion input of a product. The method of automatic control of a continuous process of a vacuum - cryodesiccation with extrusion input of a product provides for additional measurement of pressure of the product in an array of the extruder and keep it in necessary limits by adjustment of the frequency of the endless screw rotation, and also adjust a residual pressure in a zone of input of the product in the sublimation chamber by changing power of the heating elements of the extruder provided, that the allowable temperature of the product and UHF sources of heating is maintained and also adjustment of productivity of the vacuum pump. At that the final moisture of the exsiccated product is measured by the non-contact method - by attenuation of energy of UHF radiation at its passing through the product and matching the received value of the radiated power with the initial one. In case of a deflection of the value of the product final moisture from the given value in direction of rising, they first change inclination of the sources of UHF heating, enlarging the service zone of the microwave frequency field. And then increase their power. In case of a deflection of the value of the product final moisture from the given value in direction of decrease the adjustment of the power feeding is conducted in the backward sequence. The invention allows to increase accuracy and reliability of the drying process control, to decrease power consumption and also to improve the quality of the finished product.

EFFECT: increased accuracy and reliability of the drying process control, decreased power consumption, improved quality of the final product.

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