ANALYSIS OF THE INFLUENCE OF FIXING THE CORIOLIS FLOWMETER ON ZERO POINT SHIFT

Abstract

A Coriolis flowmeter is used for measuring mass flow of liquids and gases. The Coriolis
flow meters determine mass flow rate by measuring the phase shift of the U-shaped vibrating
tubes. The tubes make forced oscillations at the resonance frequency. It is drive frequency.
The phase shift is proportional to the mass flow. Therefore, changes in the phase shift amount not
related to the flow of the measured medium, leadto mass flow measurement error. The article is
devoted to the experimental evaluation of the effect of mechanical boundary conditions of
the Coriolis flowmeter on zero point shift. The zero point shift of the Coriolis flow meter is the value
of the phase difference without the flow of the medium. A special equipment, allowing to change
the stiffness of the pipeline, to which the flowmeter is attached, has been developed. There have
been conducted modal experiments on the Coriolis flowmeter with liquid for different lengths of
pipe. Changing the length of the tubing affects the modes of the coupled flowmeter-piping system. The tests were carried out on a flowmeter with tubes filled with water without flow and with
a flow of water with a constant flow rate. It has been found out that the maximum zero point shift
is observed when the frequency of natural vibrations of the coupled system of the flow meter and
piping tubes coincides with the drive frequency of tube vibrations. In the article the additional
fixation of the flowmeter for the case. To reduce the modes affecting the zero point shift.