Process and device for frequency-controlled flow measurement by the acceleration pressure process

In order to measure speed, flow and outflow in a compressible flow, particularly for very transient events in at least two places behind one another in the direction of flow in the pipe, pressure gauges are situated, by which the pressure is measured at equal time intervals. The time interval between two measurements is less than or equal to the distance between the pressure sensors, divided by the speed of sound. The measurements are processed by electronic circuits to solve the non-steady state flow equation of compressible media. If the speed of sound varies, then by expanding the device by an additional pressure sensor, the speed of sound can be determined, which value is then used in the evaluation. (orig./HP)