Multi-stage vacuum ejector with molded nozzle having integral valve elements

A multi-stage ejector for generating a vacuum from a source of pressurized fluid by passing said pressurized fluid through a series of nozzles, accelerating said pressurized fluid, and entraining air or other medium so as to form a jet flow in one or more stages and generate the vacuum to evacuate a sealed volume, the multi-stage ejector comprising:

• a primary ejector, comprising:
• a first drive stage configured for generating a first vacuum having a first pressure;
• a second stage;
• and
• a converging-diverging nozzle provided in said series of nozzles between said first drive stage and said second stage for receiving said jet flow from said first drive stage and accelerating said jet flow to form a second stage fluid jet and directing said second stage fluid jet into an inlet of an outlet nozzle of the second stage, wherein:
• said primary ejector is an ejector cartridge comprising a housing defining said first drive stage and said second stage and having a molded single material nozzle piece mounted therein;
• said housing further defines one or more openings for communicating said first drive stage and said second stage with the sealed volume;
• said converging-diverging nozzle is formed in the molded single material nozzle piece mounted in said primary ejector, and
• said nozzle piece further includes one or more valve elements integrally molded with said nozzle piece to form a single unitary piece, the valve elements designed to move from an open position to a closed position and arranged to open and close the one or more openings communicating with said second stage to control a direction of flow of the air or other medium and the fluid between the second stage and the sealed volume to be evacuated;
• and
• a booster ejector connected in parallel with the primary ejector for simultaneously generating a vacuum across a booster stage, the booster ejector configured to generate a second vacuum having a second pressure lower than the first pressure, when both the booster ejector and the primary ejector are in operation, wherein the booster ejector and said primary ejector are connected to the sealed volume to be evacuated and a valve configured to close a connection between the primary ejector and the sealed volume to be evacuated when a pressure in the sealed volume to be evacuated falls below the first pressure.