What must be done to avoid chattering in safety valves?

To avoid chattering in safety valves, it is essential to maintain a specific blow down limit. Chattering refers to the rapid opening and closing of the safety valve, which can occur if the pressure in the system fluctuates near the set pressure of the valve. If the blow down—the difference between the set pressure and reseat pressure—is too small, the valve can repeatedly open and close as the system pressure hovers around the set point. This often leads to excessive wear on the valve and can be detrimental to the system's integrity.

By establishing an adequate blow down limit, the valve is allowed to fully open and close within a defined range without constantly reacting to minor pressure changes. This not only helps to maintain the effectiveness of the safety valve but also enhances the overall safety and reliability of the pressure system. A properly set blow down limit reduces the chances of chattering and ensures that the safety valve operates efficiently in response to overpressure conditions.