Watch how each pump moves air

Follow the blue air paths from the intake to the diffuser. Both pump styles supply air to the treatment tank.

Gast-style rotary vane

An off-center rotor turns and sliding vanes carry air through the pump. Air intakeTo diffuser IN portOUT portIntake filterOff-center rotorSliding vanes

A motor turns the offset rotor. The sliding vanes create pockets that expand at the intake and shrink near the outlet, pushing air into the line.

Hiblow-style linear diaphragm

A rod moves back and forth, flexing two diaphragms while valves direct air to the outlet. Air intakeTo diffuser Upper discharge valvesLower intake valvesShared lower housingMagnetic rod

Electromagnets move the magnetic rod, flexing both rubber diaphragms. Air enters each expanding chamber through its lower intake valve and exits the compressing chamber through its upper discharge valve. Both discharge paths join in the lower housing before air leaves for the diffuser.

Motion is slowed down. These are simplified airflow diagrams; the exact external fitting positions vary by model.