Control Valve Cycle Measurement

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Thread Starter

Gerald Beaudoin

Subject: Control Valve cycle measurement

A manufacturer of a valve and actuator specs the life at 2 million cycles. They then define a cycle as 0-90 % movement.

How about the case of where the valve sits all day oscillating around 50 to 60 %? What then would constitutes a cycle for preventative maintenance purposes? Should we integrate the movement over the time period and divide by 90? Would appreciate any thoughts on this.

Cheers
Gerald Beaudoin
 
I think you are making things more complicated than it needs to be. I have never heard about measuring the cycles that a valve operated so far as a measure to do maintenance on the valve.

If you are interested in having a measurement of how much your valve have deteriorate so far, make use of a SMART positioner. Digital data from the SMART positioner can be pulled into your supervisory system via the HART protocol. One of the things that can be done is to make a footprint of the position of your valve when you first install it and then after a few months you can compare the original footprint with the current one and you will have a very clear indication at what rate the plug and seat have deteriorated over the past few months.
 
> Subject: Control Valve cycle measurement

What we have found on gearboxes for lifts is that the tooth that the cycle starts and stops on is always the same. And when these gearboxes fail, it is always that tooth that failed. Something else to consider when you set up your PM schedule.
 
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