Research about Auto Measurement of Micro Pressure Differences Based on the Liquid Manometer

The problem of measuring micro pressure differences with high accuracy has many engineering applications. These include, for instance, measurement of low flow velocities using Pitot tubes, and measurement of flow rate using nozzles. This paper studied on the structures, characteristics, and the control methods of an automatic manometer, which is based on a classical liquid manometer, using laser diode and position-sensitive detector. A zero point reading method is utilized for the measurement of micro pressure differences, and the returning to the zero position is controlled by a fuzzy controller. The automatic measurements of micro pressure differences have been carried out experimentally with good results.