| CPC F04D 25/04 (2013.01) [F04D 15/0083 (2013.01); F04D 29/053 (2013.01)] | 22 Claims | 

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               1. A gas seal column apparatus comprising: 
            a vertically-oriented pump envelope including a gas seal column and a pump; 
                a pump drive motor configured to drive the pump envelope, the pump envelope and the pump drive motor configured to be sealed together; 
                a drive shaft encased by the pump envelope between the pump drive motor and the pump to couple the pump drive motor to the pump; 
                an inlet pipe configured to receive pressurized seal gas for introducing the seal gas into the pump envelope; 
                a discharge valve configured to enable the seal gas to exit the pump envelope; and 
                a seal inlet pipe and valve configured to permit or prevent or control an amount of seal gas to pass through a sealed motor housing. 
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