A gas ultrasonic flow meter detects viscosity, density, and temperature of gas flow using mechanical sound waves. These devices are equipped to measure rate variations of ultrasonic waves as they pass through a flow medium, permitting calculation of material properties by their effect on acoustical vibrations. Transducers receive sound impulses and measure them against the differentials between sound waves that travel with and against material flows. This solid state equipment is available in sizes from handheld to clamp-on and fixed.
Three main types comprise typical gas ultrasonic flow meter equipment: transmission, Doppler shift, and open channel. Transmission types, or time of flight meters, measure transit time against the flow of a pipe, either through invasive sensing or non-invasive clamp-on units. These operate on the principle that acoustic waves traveling along a flow arrive at a different time than those traveling against a flow. Differences in response times reflect proportional changes with rate of flow. They permit analysis without interruption to any flow process.
Equipment relying on analysis of a Doppler shift effect may also be called a reflection meter. An open-channel flow meter might measure the exposed flows of rivers and culverts as well as sewers. Unlike mechanical flow meters, these technologies are less costly and invasive.
Industrial flow meters had been known for less effective performance when measuring gas compared with liquids. This is due to lower acoustic impedances and higher attenuation levels, or wave pattern losses, of gas properties. Technical innovations have permitted the widespread development of gas ultrasonic flow meter products, performing even where signal-to-noise ratios are negligible. These devices can now accurately measure the propagation of ultrasound waves through pipework. Flow media can include air, steam, natural gas, and other gas elements.
Widespread use of gas ultrasonic flow meter equipment permits numerous industries access to valuable data, which can assist in production processes and operational cost assessments. The versatility of the technology provides applications in industries dealing with wastewater, petrochemicals, and slurry. Measurement techniques such as Doppler reflections from flow particulates or bubbles do not block flows or present interfering structures that can trap insects or particles; this makes them suitable for industries that must meet hygiene standards.
This technology permits even the measurement of non-conductive fluids in a wide variety of pipe diameters and thicknesses. Gas ultrasonic flow meter equipment improves operational efficiencies from treatment plants to offshore platforms. It is able to capture flows through small tubes and ducts to large flues, in wide ranges of temperature. Some units provide options for single or dual-path transducers, as well as fixed or remote electronics.
Essentially consisting of a control interface connected with a pipe-mountable transducer pair, the equipment has many applications. The relevant principles of ultrasonic flow measurement are numerous and evolving in many fields. They can include uses not only in simple flow monitoring, but also in leak detection, inspections of fixed installation meters, power and energy management, and surveying. Equipment can range from lightweight pocket detectors to massive, complex transducer arrays on fixed structures.