Abnormal safety valve operation is not only about leakage or failure to open. Another common field issue is rapid, repeated movement of the disc after opening, producing a noisy “chattering” sound. This is flutter or chatter. High‑frequency vibration can destroy sealing surfaces and crack discharge piping supports in a few hours.The main safety valve product names of China Safety Valve Network include:JIS Safety Valve,Main Safety Valve,Overflow ValveOil Refining Specific Safety Valve,Pulse Safety Valve,Pilot Safety Valve,Pressure Safety Valve,Quick Switching Safety Valve,Spring Low Lift Safety Valve,Spring Low Lift High Pressure Safety Valve,Spring Low Lift Closed High Pressure Safety Valve,Spring Fall Lift Closed High Pressure Safety Valve

Difference Between Flutter and Chatter

• Flutter: Fast, small‑amplitude oscillation of the disc near the open position, usually caused by excessive capacity or unstable backpressure.

• Chatter: Repeated opening and closing of the disc, often with strong impact noise.

Both severely shorten valve life and require prompt action.

Root Causes

1. Safety valve capacity far exceeds system requirements
   Excessive over‑sizing causes the system pressure to drop immediately below the reseating pressure after opening; the valve closes, pressure builds up, and the cycle repeats. Solution: select a smaller orifice or a valve with a blowdown adjustment ring.

2. Excessive inlet pressure loss
   Pressure drop across long or undersized inlet piping (elbows, reducers) exceeds 3% of set pressure. The disc senses lower pressure than the vessel, causing instability. Solution: shorten inlet pipe, use long‑radius elbows, and avoid reducers.

3. High or fluctuating backpressure
   For conventional spring valves, backpressure >10% of set pressure not only raises set pressure but also causes disc oscillation. Solution: change to a balanced‑bellows or pilot‑operated safety valve.

4. Incorrect spring stiffness
   A spring that does not match the set pressure, or has lost its stiffness due to fatigue, leads to unstable disc behaviour. Solution: replace with the correct spring and verify stiffness during calibration.

Hazards

• Sealing surfaces wear out within hours, leading to severe internal leakage.

• Stem and guide bushing wear, causing sticking.

• Discharge piping and supports crack due to high‑frequency vibration.

• Impact loads can damage nearby instruments and welds.

Field Diagnosis and Actions

1. When chattering is heard, record the system pressure trend.

2. Verify that the inlet isolation valve is fully open and lead‑sealed.

3. Calculate whether the effective orifice area is too large. If excess capacity is the cause, consider adding a restricted orifice at the outlet (after checking backpressure limits).

4. For high‑backpressure systems, replace with a balanced‑bellows valve.

5. If inlet pressure loss exceeds 3%, modify piping or increase pipe diameter.

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