Dry gas curtain for cryogenic surface

摘要

An apparatus to provide a laminar curtain of dry gas over a cryogenic working surface includes a housing duct extending longitudinally from the working surface. A honeycomb member fills a section of the duct adjacent to the working surface, each honeycomb cell having a through channel in the longitudinal direction. A porous foam with through porosity fills a section of the duct adjacent to the honeycomb member oppositely from the working surface. A plenum is adjacent to the porous member oppositely from the honeycomb. Dry gas is supplied to the plenum to flow through the foam and honeycomb to effect the laminar curtain.