engleski

THERMOCOUPLE INHOMOGENEITY TESTING DEVICE

It is common practice in thermometry to test the thermocouple which is to be calibrated for homogeneity of Seeback’ s coefficient. In order to facilitate that task and save time in calibration of thermocouples, 3 years ago a Thermocouple Inhomogeneity Testing Device was developed in Laboratory for Process Measurement (LPM), University of Zagreb. The device is primarily used for the testing of thermocouple inhomogeneity (either with moving heater or for gradual immersion of thermocouple into isothermal zone). It can be also used for estimation of axial gradients in isothermal zones and hydrostatic head effects in fixed points. The sled for mounting of the heater or the thermometer is translated by a threaded shaft and a step motor in horizontal axis, vertical axis or its sliding direction can be tilted in six steps between those two positions. Sled is mounted on shafts guides with precision linear ball bearing, which allow for smooth translation. The frame of the device is designed with adjustable height and distance between legs, which allows testing in most available metrological baths or furnaces. System is controlled by custom made program on LabView platform, with ability to automatically acquire, store and analyze data test data. This paper describes the design of the testing device. The example results are also presented.

termocouple; calibration

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