Paddle-Wheel Flow Sensors Help Measure Low-Viscosity Liquids

July 1, 2010

PKP Process Instruments’ DR05 paddle-wheel flow sensors can be used wherever the flow of liquids with low viscosities must be reliably and economically measured. This includes cooling systems, demineralized water and aggressive/caustic liquids in the chemicals industry. The DR05 paddle-wheel flow sensor measures the flow of water and substances similar to water. The flow sensor consists of a section of polypropylene pipe fitted with a paddlewheel. The paddle wheel, which extends into the area of flow, is set into rotation by the flowing liquid. The rotary motion is detected by a Hall sensor and output as a series of pulses. The output frequency of these pulses is directly proportional to the flow rate. Alternatively, the pulsed output can be converted into an analog signal (4 to 20 mA) or into two limit contacts by optional integrated electronics. DR05 paddle wheel flow sensors are made completely of plastic; they have no metal parts. Wetted materials include a PP housing, ECTFE rotor and ceramic axels and bearings. Viton seals are standard (EPDM optional). These devices are available for pipe sizes of 1 inches to 2 inches with turndown ratios of up to 50:1.