ABSTRACT
The target meter combines in a single unit an annular orifice and a force-balance transducer. Output is either an electric or pneumatic signal proportional to the square of the flow. Target meters are available in sizes from ½ to 8 in. (12.5 to 203 mm) pipe diameter. The target meter is applied in a number of fields for measurement of liquids, vapors, and gases. It allows unimpeded flow of condensates and extraneous material along the bottom of a pipe and at the same time allows unimpeded flow of gas or vapor along the top of the pipe. The advantage of having a single unit combining primary element and transducer also imposes a limitation. The transducer can be zeroed only under zero-flow (nonflowing) condition. Transfer characteristics to other fluids based on Reynolds number are reliable. Because the transducer and the primary element are calibrated as a unit, overall accuracy of calibrated target meters is better than that of orifice-type systems.
