The air vacuum pump is a venturi-type AC pump that 
eliminates moisture from air-con systems, which makes it safe and easy to add refrigerant. The air vacuum pump is easy to function and pulls full vacuum within two minutes of being connected to an air range. Includes 1/2 in. ACME (R134a) and R12 connectors.
Air-driven vacuum pumps work when compressed air passing via an orifice increases its velocity and lowers its air pressure. Ambient air flow is used through stations in the generator, creating suction and vacuum. The air flow stream exits through the exhaust. … These functions require vacuum pumps.