Control valve diagnostics are valuable because they provide a way to monitor and analyze the performance of control valves in industrial processes. Control valves play a critical role in regulating the flow of fluids, gases, and other materials in pipelines and process systems, and their proper functioning is essential for ensuring that these systems operate efficiently, safely, and reliably.
Control valve diagnostics involve collecting and analyzing data on various aspects of valve performance, such as valve position, pressure drop, flow rate, and response time. This data can be used to detect and diagnose problems with the valve, such as valve stiction, valve seat leakage, or actuator problems. By identifying these issues early on, maintenance teams can schedule repairs or replacements before they lead to more serious and costly problems, such as process downtime, product quality issues, or safety hazards.
Using HART
The use of HART (Highway Addressable Remote Transducer) protocol for control valve diagnostics can provide several benefits to process industries. Here are some of them:
- Improved maintenance efficiency: HART allows remote monitoring and diagnostics of control valves, which can help identify issues with the valves before they cause significant problems. This information can be used to plan maintenance activities more effectively and prevent unscheduled downtime.
- Increased process reliability: By monitoring the performance of control valves in real-time, HART can help detect and diagnose issues such as valve stiction, incorrect positioning, or mechanical wear. This information can be used to optimize valve performance and reduce the likelihood of process upsets.
- Enhanced safety: HART can provide diagnostics that help detect abnormal valve conditions, such as incorrect valve position, which can lead to safety hazards or environmental concerns. Early detection of these conditions can help prevent accidents and reduce the risk of environmental damage.
- Improved asset management: HART diagnostics can provide valuable information about the performance and condition of control valves, which can be used to optimize maintenance strategies and replacement schedules. This can help extend the lifespan of valves and reduce maintenance costs over time.
Overall, the value of control valve diagnostics using HART lies in its ability to provide timely, accurate, and actionable information that can help improve process efficiency, reliability, safety, and asset management.
BUT, I don’t have HART!?
No worries, process data, such as pressure, flow, and temperature measurements in combination with position and setpoint data, can be used to diagnose control valve issues.
This data is normally stored in your process historians, such as OSISoft/AVEVA PI, Aspentech IP21, Yokogawa’s Exaquantum etc, but rarley used for maintenance purposes.
By analyzing the process data, it is possible to detect issues such as valve stiction, valve packing problems, valve wear, and valve positioner problems. By diagnosing these issues early, maintenance personnel can take corrective action before the valve fails, avoiding costly downtime. Have a look at: https://www.ureason.com/control-valve-app/, this app is capable determining a range of issues, continuously:
| Valve App Basic | Valve App Premium | Valve App Enterprise | |
| Controller Performance | ✓ | ✓ | ✓ |
| –Undershoot/Overshoot | ✓ | ✓ | ✓ |
| –Deadband | ✓ | ✓ | ✓ |
| –Hunting | ✓ | ✓ | ✓ |
| Packing/Bellow Wear | ✓ | ✓ | ✓ |
| Hysteresis/Stiction | ✓ | ✓ | ✓ |
| Remaining Useful Lifetime | ✓ | ✓ | |
| Cavitation*/Flashing* | ✓ | ✓ | |
| Performance Dashboards | ✓ | ✓ | |
| CMMS Integration | ✓ | ✓ | |
| Install On Premise | ✓ | ||
| Process Integration | ✓ |
It does this by using the setpoint and output (valve position) of the controller of the control valves. If position feedback is not available, additional data on controlled measurement flow/level/pressure/temperature and environment is needed.
Summary
Overall, control valve diagnostics provide valuable insights into the health and performance of industrial processes, and can help companies optimize their operations, reduce costs, and improve safety and reliability. Using process data, operational data, stored in your process historians, you can analyse a significant number of control valve issues and optimise your maintenance activities.