Anti Siphon Valve Operating Principle
Anti Siphon Valve Operating Principle
(OP)
Hey guys,
I am having a hard time grasping how an anti-siphon valve works on the common #2 fuel oil system. I have used the google search but can't seem to wrap my mind around it.
Could someone please explain how the valve actually operates? I know it is used to prevent oil from spilling out of the piping if there is a break between the valve and the pump suction. But as stated I'm having a tough time grasping the fundamentals of whats going on here, during operation of the pump. This would include first start up and priming and then continuous operation.
Thanks in advance for any help.
Rob
I am having a hard time grasping how an anti-siphon valve works on the common #2 fuel oil system. I have used the google search but can't seem to wrap my mind around it.
Could someone please explain how the valve actually operates? I know it is used to prevent oil from spilling out of the piping if there is a break between the valve and the pump suction. But as stated I'm having a tough time grasping the fundamentals of whats going on here, during operation of the pump. This would include first start up and priming and then continuous operation.
Thanks in advance for any help.
Rob





RE: Anti Siphon Valve Operating Principle
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: Anti Siphon Valve Operating Principle
It actually is like an automatic air release or vent valve. Google Air release valve or vaccum breaker and you will find it.
RE: Anti Siphon Valve Operating Principle
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: Anti Siphon Valve Operating Principle
RE: Anti Siphon Valve Operating Principle
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Anti Siphon Valve Operating Principle
Thanks for the responses, this definately helps me understand how the valves work. I do have a further question.
When applied to a traditional fuel oil system (#2 diesel) with a tank and pumpset located next to it. What is the difference in the line break versus the pump flowing oil. Wouldn't either case cause a low pressure area on the top of the gooseneck? The pump operation should draw oil our off this area and send it through the pump, thus creating a pressure slighthly lower atmospheric and allowing the atmospheric pressure on the tank surface to push the oil up the gooseneck and then have it fall to the suction of the pump.
I assume the answer here is that is has to do with varying degrees of pressure differential, because the anti-siphone valve we usually see do have a spring in them. Here is the one I am most familiar with. This seems to indicate that the opening in the line downstream removes the slight vacuum from the valve and allows it to close.
I guess stately simply it allows the slight vacuum from the oil pump to pull the valve open, but any break in the line returns the pressure to normal and the valve closes. Is this correct?
http://www.preferredutilities.com/assets/documents...
RE: Anti Siphon Valve Operating Principle
For example, 15 psia atmospheric pressure acting through a 0.25 in2 air inlet port on a ball = 3.75 lbs pushing the ball down, but 5 psia pipe internal pressure (-10 gauge pressure, allowing plenty of siphon flow) acting upwards on 1 in2 of ball surface = 5 lbs up, holding the ball against the air inlet port. If the line breaks, the liquid runs out, pressure decreases to 3 psia acting on 1 in2 of ball = net 0.75 lbs down, ball drops, allowing air in.
pressure x port size or pressure x area on which the pressure acts = force.
"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek
RE: Anti Siphon Valve Operating Principle
You understanding of the anti-siphon valve working principle is correct.
See the OPW ASV catalogue.