ventomat air valves

[colum]

Hi,

does anyone have any experience of using the ventomat air valves as a surge protection system, instead of using the standard surge vessel and compressor etc? All of the information I have been able to find so far is supplied by ventomat themselves and I was hoping to get some independent verification that the units work as claimed.

 

[ccor]

Check out thread408-89648 for a great discussion. The gist is that they can help from a transient perspective but may allow contaminated water into a distribution system. I’m assuming this is a potable water system since it’s in this forum. Also, it is important to note that they are not a panacea for transients either, still need to do the analysis with these valves.

 

[BRIS]

The ventomat is a slow closing air valve. It lets air into the pipeline under negative (sub atmospheric pressure) and slowly releases under positive pressure. Air in the pipe attenuates the surge.
You need to do the transient analysis. Obviously the Ventomat valve will not do anything if the pipeline pressure does not fall below atmospheric.
The non slam slow closure characteristics also prevent transients during pipeline filling. This can be a problem on filling long pipelines.
As Ccor notes allowing air into a potable water pipeline is a potential source of pollution and may not be permitted as a solution. In such cases I have installed the valves on riser pipes above ground in a valve house with screened ventilators.

There are other slow closure non slam air valves on the market. Ventomat is generally recognised as a good product. .

 

[BRIS]

Further you should note despite claims few transient analysis programmes are able to model two phase (air/water) flow and once air is admitted into the pipeline through air valves the analysis thereafter will probably be unreliable.

Also, for clarification, obviously as noted above the use of non slam air valves is only an option if the transient analysis shows the pressure to fall below atmospheric. In this case you should also examine other options for transient suppression to maintain positive pressures. I generally consider allowing air into the pipeline as a last resort solution.