Combination air valve. how it works?
Combination air valve. how it works?
(OP)
Hi guys,
currently im in the middle of selecting ARV for firewater system. I believe at high points a combination air valve shall be used.
can someone explain to me on how this combination air valve works? im confuse with the small orifice. is this small orifice will be used to discharge large amount of air from the beginning? im talking about orifice with diameter of 3/32" (2.38 mm).
Appreciate if you guys can help.
Thanks and regards,
Fikree





RE: Combination air valve. how it works?
The answer is probably yes, but no one can confirm this before you post detailed information (illustration) of valve innards.
(...and if you find this you will likely also find a description of the working principle, but OK - come on!)(
RE: Combination air valve. how it works?
the small orifice operates while the line is pressurized, releasing small pockets of air that collect at the high point. the large orifice opens to allow air into the pipeline during draining and allows air release during line filling
RE: Combination air valve. how it works?
Thank you guys,
Im agree with cvg, i think its called double orifice isnt it?
Ive read about it somewhere but i dont know whether this criteria is a typical for all type of combination air valves.
This is important for me since im doing the transient surge analysis. And at the moment, i use the small orifice as the venting line.
RE: Combination air valve. how it works?
RE: Combination air valve. how it works?
The only concern is, large orifice will cause the speed of water rise too fast and probability of surge happens is high. Do you know how to calculate the optimum orifice size during pipe filling?
RE: Combination air valve. how it works?
RE: Combination air valve. how it works?
Many ARV suppliers have copied designs from the 1930s (Glenfield & Kennedy). they have little understanding of how the ARV works and how it should be sized. Ventomat has done a great deal of research into ARV behaviour and provide a proven design.
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Combination air valve. how it works?
RE: Combination air valve. how it works?
i need to get this thing right, do you guys know something about a non-slam vacuum breaker?
RE: Combination air valve. how it works?
Waterhammer software packages such as Hytran and Impulse both are able to model the Ventomat air release valve.
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Combination air valve. how it works?
Best regrads
Morten
RE: Combination air valve. how it works?
On pump start up the riser is empty so the liquid accelerates rapidly. Air is expelled in a controlled manner so that the liquid column doesnt strike the closed check valve and create a high transient pressure. It goes without saying the system needs to be modelled to have any chance of selecting the correct oeprating criteria. It is useful to have the four quadrant & motor torque vs. speed data for the pump for use in the modelling.
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/