Welcome to our latest blog post. This time, we focus on common control valve repairing reasons businesses have and why successful ones have chosen to invest in proactive maintenance programs for control valves.
As we dive deeper into the topic, we explore professional advice on the signs of a failing control valve, providing a helpful guide for those invested in and newbies curious about the mechanics and maintenance of control valves.
Let’s discuss why control valve repair matters.
Reason 1: Avoiding a Critical Valve Failure
When a control valve fails, it can result in immediate disruptions to the process it controls. These disruptions may include:
To avoid a critical valve failure, organizations implement proactive maintenance programs to check on their valves and ensure they are not about to fail with solutions, such as those from Emerson’s Valve Reliability Suite:
Control Valve Repairing with Control Valve Diagnostics
Reason 2: Reducing control valve variability
Control Valve Repairing: Leakage
A digital valve controller with the ValveLink software can show signs that there is a packing leak or a decrease in friction. If the digital valve controller is Performance Diagnostics (PD) tier, you can run a Friction Test when the valve is running to capture friction values and help you to notice if the valve packing is worn out. Alternatively, an offline test from ValveLink, called a Signature Test, could be run to determine friction levels and produce the same kind of friction values.
For external leaks in a globe valve, the leak could be between the body and bonnet gasket area, through the bonnet packing stem area and the bolting area, and even the body itself if there is a crack or hole. The actuator could leak externally through the diaphragm, tubing, or a crack in the diaphragm casing.
You should also keep in mind there could be an internal leak, such as in a global valve. The leak could be between the valve plug and seat ring as a start. It can also leak internally due to worn-out, eroded, or corroded trim parts based on the process application. There could be a leak through the actuator, as well as in its diaphragm, O-ring, or actuator stem bushings. In all these cases, parts can be replaced without replacing the entire valve. The valve can also leak due to the valve not closing properly, which is covered in more detail in the next section.
Control Valve Repairing: Setpoint Issues
It is important to understand if the control valve is not closing and opening properly. If the valve is not meeting its setpoint correctly, it is a telltale sign that something may be wrong. To run an online test to check the valve is meeting its setpoint correctly, it is recommended to use three tests from the ValveLink software:
For offline test options from ValveLink, a signature test and a default step test can show that the valve is not closing all the way. If you need help checking and repairing a valve, you can reach out to a service provider.
Do you want to know which valve services companies Emerson recommends for control valve repair? Please visit our Valve Service Provider Locator webpage to find our hand-picked service providers near you. Learn more about our Accredited Service Provider program here.
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