The new Series PI (photo) is a variable-area flowmeter that utilizes a spring-loaded piston. The fluid flow in the application causes this piston to move along the axis of a precision-tapered shaft, creating a variable orifice in direct proportion to the flowrate. The piston is mechanically linked to a readout pointer and actuates switches or a transmitter. Straight pipe runs are not required before or after the meter, allowing for installation in areas with minimal space. The three-wire version of the Series PI is equipped with a solid-state relay that can be configured in the field for alarm output. — Dwyer Instruments, LLC, Michigan City, Ind.