Metering Pump With Rolling Diaphragm

M7 Series hydraulically actuated, double-diaphragm metering pumps are recommended for applications requiring accuracy, zero leakage, and low maintenance. The Series from American Lewa Inc., Holliston, Mass., features the Lewa M700 pump, which requires no special start-up or operating procedures. Full front and back-diaphragm support and a diaphragm-position-control system protect against damage from cavitation and overpressure. The pump can run dry and has a built-in pressure-relief valve. The M7 diaphragm consists of two preshaped PTFE diaphragms clamped together to move as one so no intermediate fluid or vacuum coupling is needed. An integral guide creates a rolling movement without flexure. Each diaphragm serves as backup for the other. Condition monitors signal perforation of either diaphragm, while operation continues.