METHOD OF AUTOMATIC CONTROL OF VACUUM SUBLIMATION DRYING PROCESS BY MEANS OF HEAT-TRANSFER AGENT HEATED IN COMPRESSOR OF REFRIGERATING MACHINE Russian patent published in 2005 - IPC

FIELD: vacuum sublimation drying of thermolabile products; microbiological, medical, pharmaceutical and food-processing industries.

SUBSTANCE: proposed method includes measurement of pressure in line supplying product to drier; in case this pressure exceeds permissible level, delivery of liquid product to drier is discontinued; method includes also creation of required residual sublimation pressure in drier housing and delivery of cooling agent heated in second stage of compressor to drum tubes; under action of heat of this agent desublimation of moisture from frozen product takes place and simultaneously upon completion of filling the drum product is charged and dried in second drum drier; termination of drying process is determined by relationship of temperatures of cooling agent at inlet and outlet of drum; then, cooling agent taken from pipe line between heat exchanger and desublimator is fed to drum; at throttling of this agent, temperature of drum tube surfaces in thermostatic control valve drops and desublimation pf moisture takes place; this moisture is removed from product in second drum; after blocking the perforations of second drum by desublimated moisture liquid product is introduced into its inner cavity; termination of blocking the holes is determined by rise of temperature inside perforated drum above permissible level; delivery of liquid product to drum is discontinued after critical magnitude of pressure in line supplying the product to drier has been attained and cooling agent heated in compressor is fed to tubes of revolving drum for repeated cycle of drying by above-mentioned algorithm; desublimators are changed-over for regeneration at maximum permissible thermal load on desublimators determined by thickness of desublimate on tube surfaces; provision is made for correction of flow rate of cooling agent in supply, lines, discharge lines and lines supplying it to condenser.

EFFECT: enhanced accuracy of control; possibility of using hot cooling agent.

2 cl, 1 dwg