Type Of Devices

Pressure Relief – Rupture Discs

These are thin diaphragms held between flanges and calibrated to burst at a specified static inlet pressure. Unlike relief valves, rapture discs cannot reseal when the pressure declines. Once the disc ruptures, any flow into the vessel will exit through the disc, and the disc must be replaced before the pressure vessel, can be placed [...]

25Sep2009 | admin | Comments Off | Continued

Pressure Relief – Pilot-Operated Relief Valves

Pilot-operated relief valves use the pressure in the vessel rather than a spring to seal the valve and a pilot to activate the mechanism. Figure 13-6 is a schematic of a typical pilot-operated valve. A piece of tubing communicates pressure between the relief valve inlet and pilot. When this pressure is below the set pressure [...]

25Sep2009 | admin | Comments Off | Continued

Pressure Relief – Balanced-Bellows Relief Valves

Balanced relief valves are spring-loaded valves that contain a bellows arrangement to keep back-pressure from affecting the set point. Figure 13-4 shows a cross section of a balanced relief valve, and Figure 13-5 is a schematic that shows how the valve operates. The bonnet is vented to atmosphere and a bellows is installed so that [...]

25Sep2009 | admin | Comments Off | Continued

Pressure Relief – Conventional Relief Valves

Figure 13-2 shows a cross section of a conventional relief valve and Figure 13-3 is a schematic that shows the valve’s operation. Convention al relief valves can be used anywhere that back-pressure in the relief header is low. They are common onshore where relief valves are fitted with individual tail pipes. On offshore platforms, they [...]

25Sep2009 | admin | Comments Off | Continued