About using tanks as surge protection devices

00:03

When using InfoSurge to model a water distribution system,

00:08

one of the ways to prevent hydraulic transients, or surge events, is by implementing tanks,

00:14

one of several types of surge protection devices (SPDs).

00:19

The inclusion of a surge tank in a system can make a significant difference during a surge event.

00:26

Consider what happens when a surge tank is added on the upstream side of a valve.

00:31

This example surge analysis shows that following a 2-second valve closure,

00:37

water pressure can spike and drop rapidly, going low enough to reach cavitation levels.

00:44

A surge tank drastically smooths out these pressure changes, greatly reducing the potentially damaging effects of a surge event.

00:53

It is important to understand how input data impacts tank performance.

00:59

Factors like inflow and outflow diameter, opening and closing time, inflow and outflow resistance,

01:08

and tank volume must be assigned the correct values for a tank to work properly.

01:13

You must also understand the meaning of model output fields.

01:18

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

01:26

InfoSurge supports commonly used tanks as surge protection devices, including:

01:33

Open surge tanks: These can be installed only in locations where normal static pressure heads are small.

01:41

They serve two purposes—to prevent high pressure due to upsurge by receiving liquid,

01:47

and to prevent cavitation due to downsurge by providing liquid to an area of low pressure.

01:53

One way (feed) surge tanks:

01:57

These are open or closed tanks equipped with a check valve to allow flow only into the pipe system.

02:04

They can be installed anywhere on the line and are used to avoid cavitation.

02:09

Water is discharged from the feed tank into the pipe system when low pressures develop.

02:16

Closed (compressor) surge tanks:

02:19

These surge vessels are equipped with a compressor to maintain the desired initial water level

02:25

and air volume under normal operating conditions.

02:29

They are commonly used at pump stations.

02:32

Closed (bladder) surge tanks:

02:35

These surge vessels have a pre-charged bladder

02:39

with a set pressure to maintain the desired air column under normal operating conditions.

02:44

A compressor is not required.

02:47

This type of tank is often located where no power is available.

02:52

If you know what a specific tank does, you can find a model SPD to match that behavior.

02:59

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

03:04

It is critical that a junction with an SPD has only one pipe connected to each side,

03:11

otherwise InfoSurge will create an error message that reads “invalid pipe connection at surge protection device”.

Video transcript

00:03

When using InfoSurge to model a water distribution system,

00:08

one of the ways to prevent hydraulic transients, or surge events, is by implementing tanks,

00:14

one of several types of surge protection devices (SPDs).

00:19

The inclusion of a surge tank in a system can make a significant difference during a surge event.

00:26

Consider what happens when a surge tank is added on the upstream side of a valve.

00:31

This example surge analysis shows that following a 2-second valve closure,

00:37

water pressure can spike and drop rapidly, going low enough to reach cavitation levels.

00:44

A surge tank drastically smooths out these pressure changes, greatly reducing the potentially damaging effects of a surge event.

00:53

It is important to understand how input data impacts tank performance.

00:59

Factors like inflow and outflow diameter, opening and closing time, inflow and outflow resistance,

01:08

and tank volume must be assigned the correct values for a tank to work properly.

01:13

You must also understand the meaning of model output fields.

01:18

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

01:26

InfoSurge supports commonly used tanks as surge protection devices, including:

01:33

Open surge tanks: These can be installed only in locations where normal static pressure heads are small.

01:41

They serve two purposes—to prevent high pressure due to upsurge by receiving liquid,

01:47

and to prevent cavitation due to downsurge by providing liquid to an area of low pressure.

01:53

One way (feed) surge tanks:

01:57

These are open or closed tanks equipped with a check valve to allow flow only into the pipe system.

02:04

They can be installed anywhere on the line and are used to avoid cavitation.

02:09

Water is discharged from the feed tank into the pipe system when low pressures develop.

02:16

Closed (compressor) surge tanks:

02:19

These surge vessels are equipped with a compressor to maintain the desired initial water level

02:25

and air volume under normal operating conditions.

02:29

They are commonly used at pump stations.

02:32

Closed (bladder) surge tanks:

02:35

These surge vessels have a pre-charged bladder

02:39

with a set pressure to maintain the desired air column under normal operating conditions.

02:44

A compressor is not required.

02:47

This type of tank is often located where no power is available.

02:52

If you know what a specific tank does, you can find a model SPD to match that behavior.

02:59

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

03:04

It is critical that a junction with an SPD has only one pipe connected to each side,

03:11

otherwise InfoSurge will create an error message that reads “invalid pipe connection at surge protection device”.

Video quiz

Required for course completion

When modelling a water distribution system in InfoSurge, tanks are considered a type of what?

(Select one)
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When using InfoSurge to model a water distribution system, one of the ways to prevent hydraulic transients, or surge events, is by implementing tanks, one of several types of surge protection devices (SPDs).

The inclusion of a surge tank in a system can make a significant difference during a surge event.

Effect of a Surge Tank:

Consider what happens when a surge tank is added on the upstream side of a valve.

This example surge analysis shows that following a 2-second valve closure, water pressure can spike and drop rapidly, going low enough to reach cavitation levels.

Without a surge tank, the “Before” pump discharge head graph showing water pressure spiking and dropping rapidly after 2-second valve closure.

A surge tank drastically smooths out these pressure changes, greatly reducing the potentially damaging effects of a surge event.

The “After” pump discharge head graph, showing the pressure changes greatly smoothed out after the addition of a surge tank.

Input Data and Tank Performance:

It is important to understand how input data impacts tank 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
  • Tank volume

Also important to understand the meaning of model output fields.

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

Supported Tanks:

InfoSurge supports commonly used tanks as surge protection devices, including:

Open surge tanks:

Can be installed only in locations where normal static pressure heads are small.

Two purposes:

  • To prevent high pressure due to upsurge by receiving liquid
  • To prevent cavitation due to downsurge by providing liquid to an area of low pressure

One way (feed) surge tanks:

Open or closed tanks equipped with a check valve to allow flow only into pipe system.

An image of a one way (feed) surge tank, showing a check valve to allow flow out of the feed tank to the pipe system.

Can be installed anywhere on the line and are used to avoid cavitation.

Water is discharged from feed tank into pipe system when low pressures develop.

Closed (compressor) surge tanks:

Surge vessels equipped with compressor to maintain desired initial water level—and air volume—under normal operating conditions.

An image of a closed (compressor) surge tank, with labels for the tank, unit control panel, and air compressor.

Commonly used at pump stations.

Closed (bladder) surge tanks:

Surge vessels that have a pre-charged bladder with set pressure to maintain desired air column under normal operating conditions.

An image of several closed (bladder) surge tanks, one of which is a cutaway view.

A compressor is not required.

Often located where no power is available.

Surge Analysis Considerations:

If the function of a specific tank 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”.

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