In severe services – corrosive, viscous, polymerising, or solids‑laden fluids – the safety valve cannot contact the process medium directly. A rupture disc installed at the valve inlet isolates the medium, keeping the safety valve clean and dry. But improper matching can disable both devices.The main safety valve product names of China Safety Valve Network include: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,Spring Fall Lift Safety Valve,Spring Fall Lift Safety Valve

Installation location is critical

The rupture disc must be on the inlet side of the safety valve, with a pressure gauge (or sensor) between them. When the disc bursts, pressure builds in the cavity, alerting operators. If that cavity has no vent, the trapped pressure may prevent the safety valve from opening.

Spacing between disc and valve

Fragments from a bursting disc can damage the valve seat. Provide adequate distance – API 520 recommends ≥5 pipe diameters – or use a non‑fragmenting disc (reverse buckling type). Avoid block valves in between; if unavoidable, seal them open with lead.

Pressure rating mismatch

Adding a rupture disc does not simply add its burst pressure to the valve set pressure. The sudden burst can cause a pressure surge at the valve inlet. Typically, the safety valve set pressure should be 5–10% higher than the disc burst pressure – follow the manufacturer’s recommendation.

Capacity derating

The rupture disc creates additional inlet flow resistance, reducing relief capacity. When sizing, use certified flow reduction factors for the disc‑valve combination, or select a larger valve orifice.

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