Featuring the company’s CeramPump valveless technology, the STH and STQ Ratio:Matic duplex pumps from Fluid Metering are ideal for precision mixing, diluting, and proportional metering for OEM medical, analytical, and industrial automation. The pump heads are coupled to single variable speed drive, a standard 23 frame stepper, although other drive types can be used. Each pump head’s displacement is independently adjustable and a variety of pump head sizes can be used in combination to achieve dispensing ratios from 1:1 up to 500:1. Calibrated at the factory and locked in place, the pump heads do not require recalibration in the field, even after millions of cycles. Models are also available that can be adjusted in the field for applications that require frequent changes in mixing ratios or dispense volumes. The CeramPump technology utilizes one moving part, a rotating and reciprocating ceramic piston to accomplish both pumping and valving functions without valves. The piston and mated liner are made of dimensionally stable, sapphire-hard ceramics which ensure long term, drift-free accuracy of 1% or better for millions of maintenance-free cycles.