Liquid and gas flowmeters based on the waveguide properties of pipelines

A fundamentally new type of flowmeter based on the waveguide properties of pipelines is discussed and the influence of the flow of the fluid on the critical frequencies is considered. Waveguides have a set of critical frequencies. Waves with frequencies below the critical values do not propagate, i.e., the waveguides are {open_quotes}blocked{close_quotes} to such waves. This circumstance, along with the possibility of kinematic {open_quotes}unblocking{close_quotes} of pipeline-waveguides, forms the basis for a new flowmeter. This article discusses the essence and operating principle of a new flowmeter, based on the waveguide properties of the measuring segment of the pipeline, where the fluid moving in it is probed with acoustic signals. Waves of a different kind can be used, however, because the {open_quotes}unblocking{close_quotes} of the pipeline-waveguide is kinematic.