scope:

This Guideline provides an overview of the principles and application of the flow metering of fluids (liquids and gases) with ultrasound in pipelines under capacity flow conditions. In addition to the description of the principles and methods of measurement, Standard terms are established together with methods for testing and comparison of systems for flow measurement using ultrasound. Systems for flow measurement with ultrasound include the inlet section, the acoustic primary device - usually called ultrasonic flowmeter (USF for Short) - as well as the outlet section (Figure 1). According to the Guideline VDWDE 2600 Part 3, auxiliary equipment (e.g. for power supply, indicator, recorder) also forms part of the measuring system. No detailed description of this auxiliary equipment will be given, since it consists of Standard devices. The ultrasonic flowmeter can also be used for Volumetrie measurement (volumetric flowmeter, flow Integrator) if it contains an integrating device.

When such measuring systems are used for commercial or official purposes, they shall be calibrated and subject to type approval by an official test centre, e.g. by the Physikalisch Technische Bundesanstalt (PTB), Braunschweig. In particular, the regulations of the Calibration Order as well as the special requirements for the official type approval will then apply.

This Guideline applies to ultrasonic flowmeters for the measurement of Volumetrie flow of fluids in completely filled pipelines using the transit time difference method. Furthermore, a description is provided of the fundamental principles of the Doppler method and beam deflection method. Other ultrasonic methods for flow metering are not covered by this Guide¬ line.