Pumping Apparatus For Very Cold Liquids

摘要

This invention relates to apparatus for pumping very cold liquids, such as liquid oxygen or liquid hydrogen.. It has been customary to force such liquids out of a closed container by injecting an inert gas, such as nitrogen, under the required pressure. It is found, however, that the gas when in direct contact with such very cold liquids and their metal containers may be condensed and may thus dilute the liquid to be pumped. If not actually condensed, the gas may be substantially reduced in pressure but the excessive lowering of its temperature.It is the general object of the present invention to provide improved pumping apparatus in which the has under pressure has no direct contact with the cold liquid nor with any metal which is directly exposed to said cold liquid.To the accomplishment of this general object, a pumping unit is provided in which the gas under pressure is out of contact with the cold liquid and is also effectively insulated from the cold liquid and from any metal in contact therewith, even when the pumping unit is entirely submerged in the cold liquid.