Apparatus for making carbon dioxide snow

Claim 1

Apparatus for the production of carbon dioxide snow, which apparatus comprises a genErally vertically extending hollow column, a gas exit passageway in the upper portion of said column, a gas return conduit in fluid communication with said exit passageway, nozzle means in said column in the upper portion thereof, means for supplying liquid carbon dioxide under superatmospheric pressure to said nozzle means wherein it is expanded to a mixture of snow and gas, said column including a lower accumulation section having an inner wall in the shape of a frustum of a cone with the diameter at the bottom being larger than the diameter at the top into which section the snow falls while the gas exits upward thereof, said lower accumulation section of said column being made of a material having a thermal conductivity at least about equal to that of brass, liquid conduit means in which said liquid carbon dioxide flows in traveling to said nozzle means being disposed in heat-conducting contact with the outer surface of said lower accumulation section and thereby warming said accumulation section, means to receive CO2 snow at the bottom of said column for intermittently removing said snow therefrom including a ram which moves in a cylinder which is circular in cross section and extends horizontally at the lower end of said column, said inner wall portion of said column terminating in an arcuately contoured edge extending from a point at the upper extremity of said cylinder to a point below and approximating the intersection of said cylinder and said inner wall, and a supporting flange integral with said supporting cylinder and surrounding the lower extremity of said column for securing said column to said cylinder, said cylinder having a diameter greater than the diameter of the lower end of said column, whereby the bridging tendency of carbon dioxide snow is opposed.