Valves are used to control the pressure or flow at a specific point in the network.
- Shutoff (gate) valves and check (non-return) valves, which completely open or close pipes, are not considered as separate valve components but are instead included as a property of the pipe in which they are placed (see Pipe Properties).
- The different types of valves include:
PRV (Pressure Reducing Valve)
PSV (Pressure Sustaining Valve)
PBV (Pressure Breaker Valve)
FCV (Flow Control Valve)
TCV (Throttle Control Valve)
GPV (General Purpose Valve)
- The General Purpose Valve (GPV) can be used to represent a link where the flow - headloss relationship is supplied by the user instead of following one of the standard hydraulic formulas.
- Each type of valve has a different type of setting parameter that describes its operating point (pressure for PRVs, PSVs, and PBVs; flow for FCVs; loss coefficient for TCVs, and headloss curve for GPVs).
- Valves can have their control status overridden by specifying they be either completely open or completely closed.
- A valve's status and its setting can be changed during the simulation by using Controls. (To restore a valve's control status after its status has been overridden to open or closed use a control that specifies a value for the valve setting.)
- Because of the ways in which valves are modeled the following rules apply when adding valves to a network:
- a PRV, PSV or FCV cannot be directly connected to a reservoir or tank (use a length of pipe to separate the two)
- PRVs cannot share the same downstream node or be linked in series
- two PSVs cannot share the same upstream node or be linked in series
- a PSV cannot be connected to the downstream node of a PRV.
| Field | Description | ||||||||||||||||
| Id | A unique label used to identify the valve. | ||||||||||||||||
| Start Node | The ID of the node on the nominal upstream or inflow side of the valve. (PRVs and PSVs maintain flow in only a single direction.) This is a required property. | ||||||||||||||||
| End Node | The ID of the node on the nominal downstream or discharge side of the valve. This is a required property. | ||||||||||||||||
| Diameter | The valve diameter in inches (mm). This is a required property. | ||||||||||||||||
| Type | The valve type (PRV, PSV, PBV, FCV, TCV, or GPV). See Valves for descriptions of the various types of valves. This is a required property. | ||||||||||||||||
| Setting |
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| Loss Coefficient | Unitless minor loss coefficient that applies when the valve is completely opened. Assumed 0 if left blank. | ||||||||||||||||
| Fixed Status | Valve status at the start of the simulation. If set to OPEN or CLOSED then the control setting of the valve is ignored and the valve behaves as an open or closed link, respectively. If set to NONE, then the valve will behave as intended. | ||||||||||||||||
Note: A valve's fixed status and its setting can be made to vary throughout a simulation by the use of control statements. If a valve's status was fixed to OPEN/CLOSED, then it can be made active again using a control that assigns a new numerical setting to it.