Reduction of water condensation on neck tubes of cryogenic containers

Claim 1

In a cryostat for maintaining a cryogenic liquid at the boiling point thereof, vent means comprising a neck tube protruding exteriorly from said cryostat for permitting vapor of said boiling cryogen to discharge to the atmosphere through an open end thereof and for transferring heat to said vapor prior to discharge, said heat evolved interiorly of said cryostat whereby said vapor is substantially warmed prior to the discharge thereof, ambient heat exchanger means cooperatively disposed with said vent means for transferring heat from the atmosphere to said vent means for further warming said vapor whereby atmospheric condensation on said vent means is minimized, said ambient heat exchanger means comprising tubular means for the passage of said vapor therethrough and a plurality of fins protruding radially from the exterior of said tubular means, said heat exchanger means disposed proximate the open end of said vent means.