The Data Industrial SDI Series impeller flow sensor offers accurate liquid flow measurement in closed pipe systems in an easy to install economical package. Impeller sensors offer a quick response to changes in flow rate and are well suited to flow control and batch type applications in addition to flow monitoring. The new four-bladed impeller design is rugged, non-fouling and does not require custom calibration. Coupled with the proprietary patented digital detection circuit, the sensor measures flows from under 0.3 feet per second to over 20 fps regardless of the conductivity or turbidity of the liquid. The standard frequency output produces a low impedance square wave signal proportional to flow rate that may be transmitted up to 2000 feet without amplification. Models are available to measure flow in one or both directions. All SDI insert sensors are mounted on the pipe using a 1” tap. As with any insert sensor, a pipe saddle or weld-on fitting is preferred over a service tee because it causes fewer disturbances to the flow.