Medo Pump Technology
The Linear-motor-driven Free Piston System on the Medo air pump has an internal piston inside the cylinder which is driven by an electro-magnet and spring system controlled by the alternating input current cycle.  The Medo air pump piston thus forms a single combined structure of two usually different devices; motor and pump. The system is quiet and vibration free, and offers the advantages of easy maintenance and a long operating life.

Medo's Linear Pump Operating Principle
The activated electro-magnet attracts the piston against the return spring, while air is taken into the cylinder through the opened inlet valve.
 
When the electro-magnet is deactivated, the return spring pushes the piston back, and the compressed air is brought out of the cylinder through the now open outlet valve. The system can function as either an air compressor or as a vacuum pump.

Fewer Components
The Medo air pump's unique and simple structure has no complicated transmission mechanism such as a crankshaft, connecting rods, ball bearings, etc., which are widely used in between the motor and compressor in conventional pumps.