2.5 Pressure Relief Valves

Describe the purpose of a pressure relief valve

Describe scenarios that call for pressure relief

Draw the schematic symbol for a rupture/burst disc and discuss its purpose and method of operation.

Draw the schematic symbol for a pressure relief valve and describe the purpose of the individual elements.

Describe how a check valve and heavy bias spring can be used to create a primitive pressure relief valve.

Draw a cutaway view of a spool type direct acting pressure relief valve. Describe its operation.

Describe the terms overshoot, set, reset, and span (hysteresis)

Define cracking pressure and pressure override. Discuss the influence of pressure override for actuators operating near the set point.

Differentiate between the terms pilot (control) and primary (power)

Draw a cutaway view of a balanced piston type pilot operated pressure relief valve. Describe its operation.

Describe the principle advantage of pilot operated pressure relief valves over direct acting pressure relief valves

Comment on observed properties of systems with malfunctioning, improperly set, or improperly connected pressure relief valves.

Comment on the efficiency of systems that actuate the pressure relief valve frequently.
Comment on alternate methods to prevent overpressure events without the necessity of actuating the pressure relief valve.