Pump Terms 101: Liquid Side, Air Side

Every air-operated double diaphragm pump whether Wilden, Yamada, FTI or another brand has a liquid side and an air side. Simply put, the liquid side comes in contact with the liquid to be pumped. On theFinish Thompson FTI Air FT15 air pump - choose PVDF or Polypro opposite side of the pump, the air side connects to the compressed air line.

Compressed air enters the pump through an air valve and fills one chamber while the other chamber is being filled with liquid. In a constant, back and forth motion, the air forces the liquid out of the chamber to discharge, then the cycle continues with air filling one chamber and liquid the other. Each chamber has an air side and a side for liquid.

The pump parts used on the one side may differ from the parts used on the other side, depending on the model and application. That is why parts and repair kits are often sold specifically for the air side or liquid side.

Air side parts may include gaskets, O-rings, air valve spool, pilot spool and other components. Liquid side kits may include the diaphragms, O-rings, valve balls and other components, all based on the liquid being pumped and other factors.

For guidance on diagnosing a diaphragm pump that may need a repair or replacement part, call us at 203-740-1877 or sales@reliable-equipment.com.