Download - Nivelco Process Control Co., Inc.

Level measurement in the chemical and pharmaceutical industriesDemands on high-technologymeasurements in aNorth-Hungarian Chemical-worksIn the chemical and pharmaceutical industries the accuratemeasurement of materials in the stock-storage silosis regulated by ISO standards, so the applicable measurementinstruments have to satisfy increased requirementsin this industrial area.The primary demand is high accuracy, independently fromthe measurement range. The minimal accuracy neededis 5 mm, but in several cases measurement values haveto be provided within a measurement error of 1–2 mm.In parallel with high accuracy, the long-term operationalstability required is even more stringent. The applicableregulations define several calibration procedures to beundertaken on an annual basis, without the possibilityof transporting the instruments to the factory for anyreparation or adjustment. In most cases the specialmediums to be measured require explosion-proof instruments.Moreover the instruments have to be suitable forthe measurement of materials with a low dielectricconstant (ε r).There are two product families of level transmitter solutionsdeveloped and produced by NIVELCO ProcessControl Co. which satisfy these requirements:NIVOTRACK M-500/600 magnetostrictive leveltransmitters:Typically we offer rigid rod probe versionsof NIVOTRACK transmitters up to 3-meter probelength, and flexible probe versions are recommendedabove 3 meters because of easier packaging,transporting and handling. The wide range of theapplicable floats provide reliable solutions for lowdensity (below 0.85) mediums up to 0.4 g/cm 3 viscosity.Moreover this measurement method is independentfrom the relative dielectric constant (ε r) of the measuredmedium. Stainless steel probes are not applicable foruse in chemically aggressive mediums, in this case weoffer a PFA plastic coated probe version with aplastic (PP or PVDF) float.MicroTREK H-400/500 microwave level transmitters:MicroTREK guided microwave level transmittersare very popular, especially for high temperatureapplications. Flange temperature of the stainless steelprobe versions can reach 200 °C, moreover themeasurement is not affected by physical parameterchanges of the medium, such as temperature orpressure. Since the reflection of the microwave signalsis highly dependent on the relative dielectric constant(ε r) of the measured medium, it is essential for microwavemeasurement to have ε r >1.4. In the case ofhazardous substances it is necessary to use intrinsicallysafe devices. In the applications where transparentHART communication is needed to provide remoteparametering, NIVELCO offers its new development,the UNICONT PGK-301-B Ex isolated power supplymodules.26