A Pressure Relief Valve begins to open when the pressure at the sensing node exceeds the opening pressure. The opening time is the response time for the valve to go from the start to the fully open position. The valve closure is initiated when the pressure (head) drops below the closing pressure. Because of pressure fluctuation at the sensing node, this valve can remain open for longer periods. If the valve exits to a pressurized region (e.g., a tank) the External Pressure should be specified. The pressure to activate the valve is generally sensed at the valve but any node can be used for this purpose. A pressure relief valve is normally used to prevent excessive pressure surge by venting liquid.

Disable This Surge Protection Device

If this box is checked, then the selected SPD will not be modeled in the Surge analysis.

Device Type

Type of Surge Protection Device to be used.

Pressure Relief Valve Input Data

  • Inflow Resistance - This specifies the amount of resistance to flow into the system (pipe).

  • Outflow Resistance - This specifies the amount of resistance to flow out of the system (pipe).

  • Opening Pressure - This is the pressure at the sensing node at which the valve will open. The Pressure unit is set in the Simulation Options. 

  • External Pressure - This field is the external pressure next to the pipe. A value of 0 means exiting to the atmosphere. The Pressure unit is set in the Simulation Options.

  • Closing Pressure - When the valve is open, this is the pressure at the sensing node that will cause the valve to close. The Pressure unit is set in the Simulation Options. 

  • Opening Time - This is the time in seconds that the valve takes to fully open.

  • Closing Time - This is the time in seconds that the valve takes to fully close.

  • Sensing Node ID - This is the location of the node where the sensor for the PRV is installed.

Purge - Use the Purge button to remove existing Data.

Create/Update - Enter new or changed data and exit the dialog box.

Cancel - Cancels any new or changed data and closes the dialog box.