Abstract
Differential pressure transmitters with an orifice are widely used as flowmeters in process industries. Since the most frequent problem they present is impulse line blockage, online blockage detection is required. Thus, we have developed an online method for detecting impulse line blockage loaded in a digital differential pressure transmitter. This transmitter can measure not only the differential pressure but also the static pressures at the high- and low-pressure sides of the orifice. The detecting method is based on the ratio of the root mean square values of fluctuations in measured static pressures. This methods has two unique advantages. First, it is able to detect blockages on both and either side before they affect the differential pressure measurement. Second, it is unaffected by the static operating point changes.
