Solenoid-operated metering pumps operate as positive-displacement devices, where the effects of fluid pressure, density, and viscosity are minimized, thereby increasing accuracy.
Flow rates depend upon volume displacement by the piston during each stroke, as well as the number of strokes per unit time. The units come in allstainless steel and diaphragm-isolated configurations. Seal materials include Viton, EPDM, and Teflon.