Carbon dioxide snow hood with J-horn

A compact, high efficiency, carbon dioxide snow hood adapted to provide a concentrated, well confined carbon dioxide snow deposit at low discharge velocity, said snow hood including:

• means for generating a flow of mixed carbon dioxide vapor and carbon dioxide snow;
• means coupled to said flow generating means for separating said flow of carbon dioxide snow and vapor into a first horizontally directed, concentrated stream of carbon dioxide snow and a second horizontally directed stream;
• a diffuser coupled with said flow separating means in a manner to receive only said first stream, said diffuser assembly including:
• an elongate upright tubular shell having an open bottom;
• an inlet in said shell spaced from said bottom and coupled with said flow separating means for admitting said first stream into said shell;
• a pair of arcuate, axially upright, tangentially contiguous baffles mounted in said shell and adapted tangentially intercept said first stream adjacent said inlet for dividing the stream into a pair of segregated, counterswirling streamlets of carbon dioxide snow;
• said shell extending below the lower ends of said baffles to define a mixing chamber therebeneath for the interaction of said streamlets to form larger-particle Co.sub.2 snow which is then passed in a confined, low velocity, discharge at the bottom of said shell;
• and
• an open bottomed hood surrounding said diffuser and at least a portion of said flow separating means, said hood having an exhaust port extending through a side wall thereof and adapted to receive said second stream, whereby to exhaust by aspiration carbon dioxide vapor contained in said discharge or formed beneath the hood.