Surge Protection

[Nengfrd]

Good afternoon
I would like to know your experience with 2 devices that I have observed in some installations to reduce the effects of surge pressures:
a) Dynamic combination air valve (cushioned closing)
b) Surge anticipation valve.

Would they be efficient and reliable?
How could they be modeled in the AFT Impulse software?

Thanks

 

[LittleInch]

What exactly is a " surge anticipation valve"?

Valves M usually react, not anticipate....

 

[Nengfrd]

" wave anticipation valve " opens when the line has a vacuum due to the wave and will close later when the the nominal pressure is reached, end of surge. ( like Dorot S300-REEL or Bermad MN-735 )

 

[Andrew ONeill]

a) they work as designed, but tend to leak after a little while in service, if it's critical you have no leaks, I'd avoid it. If your operating pressure is close to the opening set point, tend to leak even more.
b) don't know what this is.

c) regarding a & maybe b, usually these help to treat the symptom, and do help, but are not a silver bullet. Much better to implement controls on valve opening / closure rates, pump ramp speeds etc. If designing from scratch that's my recommendation in relation to surge.

- I have no idea how to model them in that software.

 

[HTURKAK]

Would they be efficient and reliable?
How could they be modeled in the AFT Impulse software?

Both Dynamic combination air valve and Surge anticipation valve will help . Regarding software and modelling , i know there are some pl softwares . You can see the developing surge pressure and necessary size and number of air valves .
The big question is are they reliable?
I would prefer to provide surge tank and control the pump speeds .
What is the size and length of PL ?
Last time ( before i am retired ) my company installed 4.0 meter dia . PL .

 

[pierreick]

Hi,
Consider this resource.
Probably expensive but.
You may want to ring them.
Pierre

 

[Nengfrd]

Thanks for all

pierreick, Have you ever used this device? How does its cost compare to a surge tank (hydropneumatic)?

 

[RVAmeche]

The surge anticipating valve seems to be a hydraulically actuated valve, similar to Cla-Vals used in utility/fuels piping systems. it probably senses changes in pressure and responsds, pretty neat.

 

[LittleInch]

The surge anticipation valves appear to be some sort of dual high low pressure valve for which the operation is not described well by vendors IMHO.

It seems the valves sense low pressure from negative pressure below atmospheric pressure and opens to allow in air to prevent a vacuum collapsing backwards, then somehow stays open for a while to relieve any high pressure out to atmosphere. Then closes. All simple mechanical pilot systems which could work well in certain locations and systems, but there sure isn't any anticipation going on.....

So modelling is simply a pressure activated valve on low pressure below 0 barg or a vacuum relief valve and then a pressure relief valve which opens above design pressure.

 

[LittleInch]

The other valve appears to be a joint air release and vacuum valve.

So it will allow air into the line in vacuum conditions which creates an air buffer which will act as a surge damper and a slow release of air when pressure returns.

As for reliability it probaly depends on how often they are activated and the level of dirt and maintenance.

 

[pierreick]

Thanks for all

pierreick, Have you ever used this device? How does its cost compare to a surge tank (hydropneumatic)?

No,I did not. Give them a call.
Pierre

 

[Snickster]

We used these surge relief valves in the past on some projects. This was a very long time ago so I am not sure what the present technology is.