Ejector with gas propulsion

An ejector having a driver gas at an inlet pressure, the ejector comprising:

• at least one primary branch;
• a primary driver nozzle disposed within said primary branch, said primary driver nozzle having a primary driver cross-sectional narrowing;
• a primary receiver nozzle disposed downstream of and adjacent to said primary driver nozzle;
• a primary suction line in vacuum communication with said primary driver narrowing;
• at least one secondary branch;
• a secondary driver nozzle disposed within said secondary branch, said secondary driver nozzle having a secondary driver cross-sectional narrowing;
• a secondary receiver nozzle disposed downstream of and adjacent to said secondary driver nozzle;
• a secondary suction line in interruptable vacuum communication with said secondary driver narrowing;
• and
• a closing instrument disposed upstream of said secondary driver nozzle to connect and disconnect said secondary branch in dependence on the inlet pressure of the driver gas into the ejector.