Which device is commonly used to protect a compressor from excessive discharge pressure?

Which device is commonly used to protect a compressor from excessive discharge pressure?

• A. A fusible plug
• B. A rupture disc
• C. A spring-loaded pressure relief valve
• D. A magnetic check valve

Answer: (C)

Automatic overpressure protection relies on a device that opens to vent the discharge when pressure rises above a safe limit. A spring-loaded pressure relief valve fits this purpose perfectly: it stays closed during normal operation because a spring holds it shut. When discharge pressure exceeds the valve’s setpoint, the spring is overcome, the valve opens, and gas is vented to lower the pressure. Once the pressure drops back to safe levels, the valve reseats and continues protecting the system. This reclosable, settable protection is exactly what keeps a compressor and its piping from being damaged by excessive discharge pressure. Rupture discs are single-use vents that disappear once activated, so they don’t provide continual protection after venting. Fusible plugs respond to high temperature, not pressure, and are used for heat-related safety rather than controlling discharge pressure. Magnetic check valves prevent reverse flow but do not relieve overpressure, so they don’t serve as the protective mechanism for excessive discharge pressure.

Automatic overpressure protection relies on a device that opens to vent the discharge when pressure rises above a safe limit. A spring-loaded pressure relief valve fits this purpose perfectly: it stays closed during normal operation because a spring holds it shut. When discharge pressure exceeds the valve’s setpoint, the spring is overcome, the valve opens, and gas is vented to lower the pressure. Once the pressure drops back to safe levels, the valve reseats and continues protecting the system. This reclosable, settable protection is exactly what keeps a compressor and its piping from being damaged by excessive discharge pressure.

Rupture discs are single-use vents that disappear once activated, so they don’t provide continual protection after venting. Fusible plugs respond to high temperature, not pressure, and are used for heat-related safety rather than controlling discharge pressure. Magnetic check valves prevent reverse flow but do not relieve overpressure, so they don’t serve as the protective mechanism for excessive discharge pressure.