Method and apparatus for correcting for performance degrading factors in a coriolis-type mass flowmeter

A method for determining mechanical deterioration of a vibrated conduit in a Coriolis-type mass flowmeter comprising a conduit, at least one driver for driving said conduit about a drive axis, and at least one sensor for sensing the motion of said conduit;

• said method comprising the steps of:
• driving said conduit about said drive axis,
• sensing the motion of said conduit and producing one or more signals representative of said motion,
• monitoring a noise portion of the frequency spectrum of at least one of said signals corresponding to frequency components of the motion higher than a predetermined threshold value, and
• signalling an alarm response when an increase in the noise portion of the frequency spectrum exceeds a predetermined threshold noise value.

A method for determining mechanical deterioration of a vibrated conduit in a Coriolis-type mass flowmeter comprising a conduit, at least one driver for driving said conduit about a drive axis, and at least one sensor for sensing the motion of said conduit;

• said method comprising the steps of:
• driving said conduit about said drive axis,
• sensing the motion of said conduit and producing signals representative of different aspects of said motion,
• monitoring a change in the ratio of values of said signals,
• signalling an alarm response when said change in said ratio exceeds a predetermined threshold value indicative of excessive mechanical deterioration,
• monitoring a noise portion of the frequency spectrum of at least one of said signals corresponding to frequency components of the motion higher than a predetermined threshold value, and
• signalling an alarm response when an increase in the noise portion of the frequency spectrum exceeds a predetermined threshold noise value.

A method for determining mechanical deterioration of a vibrated conduit in a Coriolis-type mass flowmeter comprising a conduit, at least one driver for driving said conduit about a drive axis, and at least one sensor for sensing the motion of said conduit;

• said method comprising the steps of:
• driving said conduit about said drive axis,
• sensing the motion of said conduit,
• producing from the sensed motion a first signal representative of a first aspect of said motion,
• producing from the sensed motion a second signal representative of a second, different aspect of said motion,
• generating a ratio of values of said first and second signals,
• detecting excessive mechanical deterioration of the conduit by comparing a change in the ratio of values of said first and second signals to a predetermined threshold value indicative of excessive mechanical deterioration of the conduit,
• signalling an alarm response when said change in said ratio exceeds the predetermined threshold value indicative of excessive mechanical deterioration.

A method for determining mechanical deterioration of a vibrated conduit in a Coriolis-type mass flowmeter comprising a conduit, at least one driver for driving said conduit about a drive axis, and at least one sensor for sensing the motion of said conduit;

• said method comprising the steps of:
• driving said conduit about said drive axis,
• sensing the motion of said conduit and producing signals representative of said motion,
• monitoring a noise portion of the frequency spectrum of at least one of said signals corresponding to frequency components of the motion higher than a predetermined threshold value,
• signalling an alarm response when an increase in the noise portion of the frequency spectrum exceeds a predetermined threshold noise value,
• monitoring power delivered to said conduit necessary to maintain a constant vibrational conduit velocity, and
• signalling an alarm response when an increase in the power delivered exceeds a predetermined threshold power value.

A method for determining mechanical deterioration of a vibrated conduit in a Coriolis-type mass flowmeter comprising a conduit, at least one driver for driving said conduit about a drive axis, and at least one sensor for sensing the motion of said conduit;

• said method comprising the steps of:
• producing a drive signal that drives said conduit about said drive axis;
• sensing the motion of said conduit and producing a motion signal representative of said motion,
• interrupting the drive signal;
• monitoring said motion signal to monitor decay of the oscillation of said conduit to determine a damping factor for said conduit;
• and
• signalling an alarm response when a change in said damping factor exceeds a predetermined threshold value indicative of excessive mechanical deterioration.