Measurement and control. Automation. Liquid fill level trends. the float principle is close by

The tank contents sensing probes of the Weka company provide a cost effective solution where continuous surface or interface measurement provide a problem. Surveys in the chemical industry indicate that users of sensors for this type of measurement consider as the foremost criterion accuracy (27%), installation costs (65%), maintenance friendliness (74%), and reliability (87%). The robust construction of the Weka float sensor for liquid level measurement meets the highest demands including up to military applications. Standard measuring devices are made of 316/316L stainless steel or yellow brass, Hastelloy or titanium. The probes can also be coated. The range of coating materials is from a 1:1 alternating copolymer of ethylene and chlorotrifluoroethylene (Halar) to perfluoro (alkoxy vinyl ether) (PFA) and fluorinated ethylene propylene copolymer (FEP). These coatings have no influence on the measuring principle and support the self-cleaning effect of the float that by its movement exerts a self-cleaning effect on itself. With a large variety of available floats, applications are made to order. In contrast to physical measurements of electronic origin such as ultrasound and radar, the entire range of measurement is sensed by a single float motion. The checking is simple and needs no cost intensive training. Independent of pressure, temperature, and dielectric constants, foam buildup or motions of the media the signal output is stable and linear. For different measurement lengths there are various resolutions of 2.5, 5, to 12.5 mm available. The measurement accuracy over the entire measuring length is smooth and accurate to about 1 mm depending on the type of probe. This corresponds to a deviation of 0.1% for a 1 m high tank. With respect to the pressure device directive of May 29, 2002, these float devices must be considered in connection with their containers. The Weka company is certified within the quality management system ISO 9001:2000 according to module H/H1 of the 97/23/EC pressure equipment directive (PED) guideline. The use of electrical and non-electrical operating media in areas in danger of explosion is controlled by the 94/9/EC (ATEX) guideline. For such applications, tank contents measurement probes can be offered with type tests that may be used in the group of atmospheres in danger of explosion from gases, vapors, and mists in Zone 0. Photograph.