The air vacuum pump is a venturi-type AC pump that eliminates moisture from air-con systems, making it safe and easy to add refrigerant. The air vacuum pump is easy to operate and pulls full vacuum within two moments of being linked to an air collection. Contains 1/2 in. ACME 
(R134a) and R12 connectors.
Air-powered vacuum pumps work when compressed air moving via an orifice increases its velocity and lowers its air pressure. Ambient air flow is drawn in through stations in the generator, creating suction and vacuum. The atmosphere stream exits through the exhaust. … These functions require vacuum pumps.