A double walled nonpressurized cryogenic storage container having an elongated neck tube in combination with a closure assembly for the neck tube. The closure assembly includes a neck plug and a neck tube adapter having access means for sensor and fill lines. The neck tube adapter has an outer shell...http://www.google.de/patents/US4411138?utm_source=gb-gplus-sharePatent US4411138 - Neck tube closure assembly for cryogenic containers
