McMenon MAPT averaging pitot tubes

Click2Contact

The McMenon MAPT is a multiport self-averaging flow meter with a design based on the classical pitot tube concept of fluid flow measurement. It produces an averaged differential pressure (DP) signal proportional to the square of the flow rate. The DP output is normally piped to a differential pressure transmitter in order to generate an electrical signal proportional to the flow rate.

The outer impact tube has a number of pressure sensing holes facing upstream that are positioned in accordance with a log-linear distribution. The ‘total pressures’ developed at each upstream hole by sum of the impact of the flowing medium and the static pressure are firstly averaged within the outer impact tube and then more accurately averaged within the internal averaging tube. This pressure is represented at the head as the high-pressure component of the DP output. The low-pressure component is generated from a single sensing hole located on the downstream side of the outer impact tube, measuring static pressure. For bidirectional flow measurement, the MAPT can be supplied with the same number of downstream ports as upstream. The MAPT is an improvement on the round sensor design due to profiled flats positioned around the downstream hole in order to define the point at which the flow lines separate as the fluid passes around the outer impact tube. This creates a stable pressure area at the downstream pressure sensing hole, maintaining a more constant flow coefficient at high velocities and enabling a very wide range of flow measurement.