Abstract: Dry calibration technique of electromagnetic flowmeters is presented, including its principle, present research status and prospect of industrial application. The precise measurement of the distribution of magnetic field in the effective zone of the electromagnetic flowmeters is indicated as the key factor which impacts the industrial application of dry calibra-tion technique. The direct measurement of the distribution of magnetic field, however, is presently unavailable, therefore, an effective method is introduced to obtain indirectly the distribu-tion of magnetic field through measuring other physical pa-rameters caused by the electromagnetic induction using the alternating characteristic of magnetic field. The principle, fea-tures and implement of two indirect dry calibration methods, eddy current field measurement method and surface weighting function method, are discussed, which provides a useful refer-ence for the research of dry calibration technique of electro-magnetic flowmeters and its industrial application in China.

Key words: Dry calibration, Eddy current field, Electromagnetic flowmeter, Weighting function