OPTIFLEX IMPROVES MEASUREMENT ACCURACY AND RELIABILITY

KROHNE 25/03/2008

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DEZA as, a leading processor of crude benzol and coal tar, has installed KROHNEs OPTIFLEX 1300 TDR radar level meter to improve the accuracy and reliability of naphthalene measurement at its plant in the Czech Republic.

Liquid naphthalene is used in the production of various chemicals. At DEZAs plant it is contained in a 3.3 metre cylindrical horizontal tank where it is heated to 100C before being used in production processes. The substance has a very low dielectric constant of around 2.2 at 100C which makes it particularly difficult to measure.As well as improving the accuracy and reliability of level measurement in the tank, DEZA needed an instrument with 2-wire connection and local indication. It also had to be of robust design to cope with harsh conditions within the plant and be able to operate within a hazardous area.

Technicians from KROHNE (www.krohne.co.uk) specified an OPTIFLEX 1300 TDR level meter with a single 8 mm diameter rod. This configuration is resistant to the liquid naphthalene and its vapours and also allows the length of the sensor to be modified if required.The instrument delivers a measurement accuracy of ± 3 mm at a maximum allowable flange temperature of 200C – well above the actual flange temperature of 150C.The instrument is also equipped with a local indicator and a protection cover which protects the converter from the harsh conditions. It is loop-powered (providing 2-wire connectivity) and is flameproof to ATEX EEx d standard.Engineers at DEZA evaluated the OPTIFLEX over a two month period.

The instrument proved to operate accurately and reliably despite the high temperature and low permittivity of the naphthalene.During final installation, KROHNE engineers recommended that the upper flange of the tank was insulated to prevent naphthalene depositions forming on the OPTIFLEX sealing system.

For more information contact Krohne Ltd, Wellingborough, Northants

Tel: 01933 408500 Fax: 01933 408501

E-mail: info@krohne.co.uk Web: www.krohne.co.uk