Valve Chatter and How To Fix It
Do you hear a faint tapping or rattling noise coming from the area of a pressure release or emergency shutoff valve? It’s called “valve chatter,” and it could signify an impending valve failure.
The question isn’t simply how to fix it, but why is it occurring in the first place? And what, precisely, is wrong with the valve? Taking some time to understand valve chatter can resolve a valve problem, ensure it doesn’t recur, and give you peace of mind that critical safety and control valves will work when they’re needed.
What is valve chatter?
Valve chatter is an excess of vibration affecting check or pressure release valves. As the valve vibrates, it begins to open and close quickly and repeatedly, which causes the clicking or rattling noise we associate with “chatter.”
Valve chatter is common, affecting as many as 25% of all check and release valves in an industrial setting. The degree of chatter varies depending on application, which can make it easier, or more difficult, to identify chatter by simply listening for it.
Why does valve chatter occur?
Valve chatter is most frequently traced to a pressure drop at the inlet of the valve, which is commonly associated with an improperly sized valve. Valves can develop chatter when they’re not equipped to handle the PSI of the application for which they’re used. Often, the valve is oversized for the application.
When relief valves begin to chatter, it causes excessive wear on the valve mechanism, with detrimental results, including:
- Spring failure that can inhibit a valve’s opening/closing action.
- Poppet damage that can disrupt valve timing.
- Distortion of the valve seat, which leads to valve failure.
Neglected long enough, valve chatter will result in failure — meaning valves will not function properly to prevent backflow, or they will create a safety hazard by sticking in an open or closed position.
Resolving valve chatter
What’s the next step when you’ve diagnosed valve chatter? Fixing it generally means replacing the valve with one appropriately sized and rated for the flow capacity of the application. This requires a precise understanding of the temperature, pressure, media, flow rate, and viscosity of material flowing through the valve.
Rather than sizing a valve by pipe size or flow coefficient, select a replacement relief valve that enables a minimum 1-PSI pressure drop. This method allows for proper regulation while eliminating the pressure drop causing the valve to chatter.
Don’t ignore valve chatter
Valve chatter is a common issue you’re likely to encounter in an industrial setting. Ignore it at your peril. Chatter can continue for extended periods before valve failure, but for every day it remains unchecked, there is potential for a backflow or relief failure, both of which lead to bigger problems. Replacing valves with appropriate models is simple and one of the best opportunities for proactive maintenance in modulated flow applications.