Liquefied gas transfer apparatus

Claim 1

Apparatus for transferring liquefied gas from a closed tank to a container, comprising a discharge pipe having an outlet end to which a container is connectable and having an inlet end, a glandless pump connected with the inlet end of said discharge pipe and whereby liquefied gas is drawn from said tank and is delivered to said discharge pipe, an electric motor by which the pump is driven and to which the pump also delivers withdrawn liquefied gas to be circulated through the motor and back to the tank for motor cooling and lubrication, and a valve connected in the discharge pipe between its said ends and movable between an open position permitting flow of liquefied gas to said outlet end and a closed position preventing such flow, said apparatus being characterized by: switching means (1) having an operative connection with said valve to be responsive to the position thereof, and (2) connected with said electric motor and arranged (a) to energize said motor for operation at a high speed when said valve is in its open position, so that said pump can then deliver liquefied gas from said tank to a container connected with the discharge pipe as well as to the motor, and (b) to energize said motor for operation at a substantially lower speed when said valve is in its closed position, to thereby prevent vaporization of liquefied gas in the pump and the motor with a low expenditure of electric power while maintaining delivery of liquefied gas to the motor for its cooling and lubrication.