Improvements in and relating to the recovery of volatile liquids

摘要

In the recovery of solvent vapour from solutions employed in an installation for the making of films, foils, coated papers, &c., fire risk is reduced by indirectly cooling the vapour in a condenser 4 with solid carbon dioxide contained in a receptacle 5 around which the vapour is circulated, the gaseous carbon dioxide evolved being recirculated from a gas holder 12 by a fan 15 to the vapour collecting space 2 of the installation. The condensed solvent vapour collects at the base of the condenser, and the vapour-free, carbon dioxide containing, air circulates to the collecting space 2 through a duct 7, the vapour-laden air flowing back to the condenser through a duct 8 to continue the cycle of operations. In a modification, slower gasification of the solid carbon dioxide is achieved, by arranging the receptacle 5 outside the condenser 4, a pipe coil surrounding a block of the carbon dioxide communicating with a similar coil in the condenser, the coil being empty or filled with methyl chloride to form a supplementary refrigerant. A pump may be inserted in the pipe line 11 between the receptacle 5 and the gas holder to create pressure in the latter; in this modification the gas holder may be dispensed with. The quantity of carbon dioxide admitted to the system may be controlled by a meter 28 and the temperature in the condenser regulated by an electrical thermometer.