Characterization of fluidised bath

Osnovni zadatak ovog završnog rada je ispitivanje karakteristika fluidizirane kupke s aluminijevim oksidom, u temperaturnom rasponu od 200 °C do 600 °C, koja služi za umjeravanje termometara. Potrebno je odrediti parametre koji imaju utjecaj na nesigurnost usporednog umjeravanja termometara u kupki. Ispitivanjem je obuhvaćena karakterizacija zone kontrolirane temperature što uključuje određivanje radijalnih i aksijalnih gradijenata te temperaturnu stabilnost, metodom koja se koristi u Laboratoriju za procesna mjerenja na Fakultetu strojarstva i brodogradnje u Zagrebu. Nadalje je metoda detaljno objašnjena sa pripadajućim formulama i parametrima. Također je i opisan postupak mjerenja te su dani i opisi korištene opreme i uvjeti mjerenja. Na kraju su prikazani rezultati ispitivanja u zadanim točkama s određenim doprinosima ukupnoj mjernoj nesigurnosti.The main goal of this paper is to describe testing of characteristics of a fluidised calibration bath, filled with alumina powder, in a temperature range from 200 °C to 600 °C. The bath is normally used for comparison calibration of thermometers. To be used for this purpose, it is necessary to periodically determine the parameters that have an impact on the uncertainty of the calibration of thermometers in the bath. The study included the determination of the controlled temperature zone, which includes the determination of radial and axial gradients and temperature stability by the method used in the Laboratory of Process Measurements at the Faculty of Mechanical Engineering and Naval Architecture in Zagreb. Furthermore, the method is explained in detail with the corresponding formulas and parameters. The measurement procedure is also described as well as measurement conditions and the equipment that was used. Finally, the test results are given for temperature points 200 °C, 400 °C, 500 °C and 600 °C, together with the baths contributions to the overall measurements uncertainty, when it is later used for comparison calibration of thermometers