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