Diagnostics of impulse line blockage with multi-sensing differential pressure transmitter in oil line

A differential pressure transmitter with an orifice is widely used as a major field flowmeter. A major drawback of this flowmeter at the operation site is the blockage of the impulse line, which connects an orifice tap with a differential pressure transmitter. In this study, we investigate the relation between the amplitude of the pressure fluctuation in the oil line and the kinetic viscosity (1.0 times 10^-5 to 3.0 times 10^-5 m²/s). By conducting experiments in a water line, we have developed a method to diagnose the blockage of the impulse line. Hence, we use this method to diagnose the blockage in a line that carries a highly viscous fluid. Through experimental investigations, the following results are clarified: 1) The highly viscous fluid in the impulse line does not reduce the pressure fluctuation occurring at the multi-sensing differential pressure transmitter. 2) Highly viscous flow in the main line has small pressure fluctuations; however, these fluctuations have the same characteristics of the impulse line blockage as those in a water line. Therefore, the proposed method can diagnose the impulse line blockage in an oil line as well as in a water line.