About using valves as surge protection devices

There are devices in InfoSurge that help to reduce the magnitude of pressure waves when a transient occurs in the system.

These devices are created by first creating a node and then changing it into a surge protection device (SPD).

Valves are one type of SPD in InfoSurge.

There are a few main types of valves, each with distinct impacts on surge results:

• Gate valves: often used for smaller isolation valves
• Globe valves: a common control valve type
• Butterfly valves: often used for larger isolation valves

Input Data and Valve Performance:

For a valve to work properly, correct values must be assigned for factors such as:

• Inflow and outflow diameter
• Opening and closing time
• Inflow and outflow resistance
• External pressure

Also important to understand meaning of model output fields, such as inlet and outlet pressure, and external flows and volumes.

For more information on input and output data, visit the InfoSurge help pages on the Autodesk website.

Supported Valves:

InfoSurge supports many other valves, such as:

Pressure relief valves (PRV):

Begin to open when pressure at sensing node exceeds opening pressure. Excessive high-pressure surges are prevented by ejecting water out of a side orifice.

Surge anticipation valves (SAV):

Activate on a downsurge when pressure at sensing node drops below opening pressure. Ideal for solving problem of upsurge at pumps due to reverse flow or wave reflection in systems where water-column separation will not occur.

Single and two-stage air vacuum valves (AVV):

Take air in when pipeline pressure drops below atmospheric pressure and releases air when exceeding it.

Single stage AVV usually has same orifice for inflow and outflow.

Two-stage AVV has different orifice for inflow and outflow, with smaller outflow orifice to reduce air slam when all air is expelled and liquid columns rejoin.

Three-stage air vacuum valves:

Have one orifice to allow air in and two outlet orifices—first is large to allow air to be expelled quickly, second is smaller to reduce air slam by releasing air more slowly.

Hydraulically actuated anticipation valves (Hyd-SAV):

Models both low pressure pilot (LPP) during downsurge and high-pressure pilot (HPP) during upsurge.

Surge anticipation valve that is controlled by pressure rather than time.

Electrically actuated anticipation valves (Elec-SAV):

Start opening on pump trip condition, stay open for specified time, and then close.

Combination of regular SAV and Hyd-SAV that requires entering a delay time as additional data item.

Model SPD:

If the function of a specific valve is understood, a model SPD can be found to match that behavior.

Note that in a surge analysis, SPDs are placed on a junction.

IMPORTANT: A junction with an SPD must have only one pipe connected to each side, or InfoSurge displays the error message: “Invalid pipe connection at surge protection device”.