Direct contact halocarbon freezant apparatus

Claim 1

A direct contact liquid freezing apparatus comprising a. a chamber having an inlet and an outlet open to the atmosphere, b. conveying means for introducing articles through the inlet into the chamber and thence drawing the articles from the chamber through the outlet, c. means for exposing the articles within the chamber to direct contact with a halocarbon freezant refrigerated within an open vessel to a temperature below 0* C., d. a first condenser supported in said chamber at a level not exceeding the inlet and outlet levels and operative at a temperature at leasT below the boiling point of the halocarbon freezant so that the freezant manifests a lowered vapor pressure, e. a conduit disposed in the upper portion of said chamber above said first condenser and in communication with atmosphere, f. a second condenser supported in said conduit and operative at a temperature substantially below that of said first condenser to further reduce the freezant vapor pressure, g. blower means in said conduit for drawing air and freezant vapor within the chamber through said first and second condensers and discharging air with diminished concentration of vapor entrained therein through the conduit to a point outside the chamber while reducing chamber pressure below atmospheric, and h. means for collecting halocarbon freezant vapor condensed on said first and second condensers and returning the condensed halocarbon freezant to the vessel.