Patent attributes
A cryogenic tank car tank includes an outer tank, an inner tank positioned within the outer tank, an inner nozzle, and inner manway plate, an outer nozzle, and an outer manway plate. The inner nozzle defines an opening in the inner tank. The inner manway plate is welded to the inner nozzle and covers the opening in the inner tank. The outer nozzle defines an opening in the outer tank and is positioned above the inner nozzle, such that the inner manway plate is accessible through the outer nozzle. The outer manway plate couples to an upper edge of the outer nozzle to cover the opening in the outer tank. In response to applying the vacuum to the annular space between the inner and outer tanks, a differential pressure between the annular space and a space external to the outer tank secures the outer manway plate to the outer nozzle.
