Diaphragm Pump

A diaphragm pump is a reciprocating positive displacement pump in which a flexible membrane moves back and forth to change the volume of a pumping chamber, with inlet and outlet check valves controlling the flow direction. Because the diaphragm separates the liquid from the drive mechanism, the pump is seal-less and leak-free. Air-operated double-diaphragm (AODD) pumps are driven by compressed air, can run dry and handle abrasive, viscous and solids-laden liquids; mechanically or hydraulically actuated diaphragm pumps provide precise metering. Diaphragm materials include PTFE, EPDM, nitrile and thermoplastic elastomers, selected for chemical compatibility and temperature. Typical applications include chemical transfer, slurry handling, paints and coatings, wastewater and chemical dosing. Selection considers flow, discharge pressure, material compatibility, pulsation (often reduced with dampeners) and air consumption. API 675 covers controlled-volume pumps, including hydraulically actuated diaphragm metering pumps.

Examples

• AODD pump for drum and tote chemical transfer
• Hydraulically actuated metering pump for corrosion inhibitor injection
• Diaphragm pump for slurry and sludge handling

Related terms

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