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Coriolis mass flowmeters under entrained gas conditions - .PDF file.

Coriolis mass flow meter

Coriolis mass flowmeters are usually only used for single-phase fluids, i.e. either liquids or gases, since it has been found that their accuracy can be affected by two-phase flows, e.g. the existence of entrained gas in a liquid flow. It is now known that there are various sources of error, among which the significantly increased compressibility due to gas entrainment brings the most difficulty when Coriolis meters are used in the field.

The authors of this white paper have developed a new Coriolis sensor together with an innovative technology, Multi-Frequency Technology (MFT), which can compensate the measurement errors introduced by the increased compressibility of an entrained gas flow. The new Endress+Hauser Coriolis sensor provides a novel hardware platform so that a higher natural mode of the measuring tube can be reliably excited in addition to the basic working mode. Being driven at different frequencies, the same two phase fluid in the measuring tube can have different influences on the primary mode (i.e. the basic working mode) and the auxiliary mode (i.e. the higher tube mode).

By analyzing the corresponding vibrational response of the two phase fluid at the two frequencies, the unique resonance property of this mixture can be obtained and the induced measurement errors can be compensated. In this paper, the theoretical background of Coriolis entrained gas metering is given. Afterwards, the basic principle of the MFT is explained in detail. Measurement data obtained at two independent laboratories are provided to prove the improvement brought about by this technology.


Endress+Hauser is a global leader in measurement instrumentation, services and solutions for industrial process engineering. With over 8,000 employees worldwide, the Group generates annual net sales of more than Euro1.1 billion.

The Endress+Hauser Group

Endress+Hauser is a global leader in measurement instrumentation, services and solutions for industrial process engineering. The Group employs 13,000 personnel across the globe, generating net sales of more than 2.1 billion euros in 2015.
With dedicated sales centres and a strong network of partners, Endress+Hauser guarantees competent worldwide support. Production centers in 11 countries meet customers’ needs and requirements quickly and effectively. The Group is managed and coordinated by a holding company in Reinach, Switzerland, with UK headquarters in Manchester. As a successful family-owned business, Endress+Hauser is set for continued independence and self-reliance.
Endress+Hauser provides sensors, instruments, systems and services for level, flow, pressure and temperature measurement as well as analytics and data acquisition. The company supports customers with automation engineering, logistics and IT services and solutions. Our products set standards in quality and technology.
We work closely with the chemical, petrochemical, food & beverage, oil & gas, water & wastewater, power & energy, life science, primaries & metal, renewable energies, pulp & paper and shipbuilding industries. Endress+Hauser supports its customers in optimising their processes in terms of reliability, safety, economic efficiency and environmental impact.
Founded in 1953 by Georg H Endress and Ludwig Hauser, Endress+Hauser has been solely owned by the Endress family since 1975. The Group has developed from a specialist in level measurement to a provider of complete solutions for industrial measuring technology and automation, with constant expansion into new territories and markets.

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