An ejector-type vacuum pump assembly, said ejector-type vacuum pump assembly comprising:
- an ejector-type vacuum pump comprising:
- a pressure chamber;
- an ejector nozzle;
- a vacuum chamber;
- a suction opening;
- and
- an exhaust, the ejector nozzle fluidly connecting the vacuum chamber with the pressure chamber;
- and,
- a flow control unit for controllably exiting a flow of pressurized air to be fed to an ejector-type vacuum pump, said unit comprising:
- an inlet for pressurized air;
- first flow-control valve comprising:
- a valve chamber, the first flow-control valve being configured to control a flow of pressurized air exiting the valve chamber to be fed to the ejector-type vacuum pump, the valve chamber being fluidly connected to the inlet for pressurized air;
- the valve chamber comprising:
- a bottom having an opening, a wall having an orifice configured to exit the flow of pressurized air from the valve chamber;
- wherein, in the valve chamber of the first flow-control valve, a flexible, collapsible, cylindrical membrane is housed, the flexible, collapsible, cylindrical membrane being configured to seal against the bottom and/or to the wall, and, in a relaxed, un-collapsed state of the collapsible, flexible cylindrical membrane, to seal the orifice, the first flow-control valve further comprising an inner rigid flow chamber comprising, in an upstream end thereof, a flow restriction fluidly connecting the valve chamber with the rigid inner flow chamber, and, in a downstream end thereof, an outlet fluidly connected to the opening, the rigid inner flow chamber having in a side wall an orifice fluidly connecting the inner flow chamber with an inner volume enveloped by the collapsible, cylindrical, flexible membrane and the bottom, the upstream end of the rigid flow chamber being sealingly connected to an opening in an upstream end of the collapsible, cylindrical, flexible membrane, the flow control unit additionally comprising:
- a second flow-control valve configured to regulate a pilot flow of pressurized air exiting the inner flow chamber to be fed to the ejector-type vacuum pump.
- wherein the pressure chamber of the ejector-type vacuum pump is fluidly connected to the orifice and to a downstream side of the second flow-control valve.