Shear and Lamb Waves

The principle of FLEXIM's ultrasonic flow measurement of liquids and gases relies on the propagation of ultrasonic wave signals into the medium.

Besides a high accuracy and operational safety, there are additional criteria regarding the design and selection of the appropriate ultrasonic transducer technology. 

As the sole manufacturer worldwide, FLEXIM offers different transducers series with Shear- and Lambwave technology. 

FLEXIM's shear wave transducers are mostly used for the flow measurement of liquids - our Lamb Wave transducers, in particular, for the flow measurement of gases.

FLEXIM's shear wave transducers are suitable for all common pipe materials such as steel or GFK and are thus universally applicable. In the case of the shear wave transducers, the angle of refraction on the interfaces results from the media pairing. There a different variants for gases and liquids. Due to the special design, one transducer pair covers a very wide application range. Due to continuous improvements on the design of the FLEXIM shear wave transducers, applications can be covered which are normally reserved by other technologies.

FLEXIM's Lamb wave transducers make use of a property once discovered by the british physicist Horace Lamb - they emit a broad signal front into the flowing media. The transducers are available for pipes with different wall thicknesses made of steel and Duplex and are primarily used for the gas flow measurement. Thereby an operational safe measurement is as well possible at comparatively low pressure and on wet gas.

In the specifications for the transducer development, especially real world applications have been the driving requirements. As a consequence, all FLEXIM transducers show a very good acoustical degree of efficiency, an excellent zero point stability and are insensitive in respect to non-ideal conditions such as a wrong transducer positioning due to temperature and media changes.

Moreover, there are no upper limits for FLEXIM's transducers in respect to the pipe wall thickness: They are working faultlessly even on very thick pipe walls, e.g. on highly pressurizes pipes.

All of FLEXIM's transmitters are compatible to both transducers technologies, so that the measurement system can be optimally adjusted to the individual application.