Increased level measurement accuracy

Paul Boughton
Continuous level measurement has traditionally been achieved using a displacer method, however, there have always been inherent disadvantages to this due to accuracy of the operating specific gravity (SG), calibration and set up and on-going maintenance of moving parts.

A new maintenance-free and more accurate solution is available from TC-Klinger based on the guided wave radar (microwave) principle.

This development is particularly suitable for high accuracy and reliable operation in high temperatures and pressures such as those experienced in the offshore, petrochemical, power, food and pharmaceutical industries. Microwaves are not sensitive to dust, vapours and foam and are unaffected by changes in SG.

As with all instruments, criteria must be laid down to ensure the gauge will work reliably in a specific environment. Once set up however, the instrument requires no further adjustment or calibration and will operate, free of maintenance, for its lifetime.

The guided wave radar principle relies on a pulse of microwave energy transmitted along a rod, wire or coaxial antennae, depending on application.  As this microwave meets a change in the dielectric constant (ie, the product surface) an energy reflection occurs. This ‘echo’ is bounced back where it is analysed and converted to a level indication by the electronic module in the signal processing unit.

TC-Klinger provides an instrument that can be mounted directly into the process vessel, on the side of the process vessel (bypass chamber) or depending on design, into an existing side mounted chamber. For extra security of measurement the Guided Wave Radar can be combined with the proven technology of the Magnetic Level Gauge at little extra cost (LevelSure). This provides a mechanical visual signal at the point of use allowing the operator to compare the guided wave radar signal with the direct reading from the Magnetic Level Gauge.

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