5 replies to this topic

[v8landy]

Hi

As stated in API 2000 , 4.4.1.2

“a flame arrestor is not considered necessary for use in conjunction with a PV valve venting to atmosphere because flame speeds are less than vapour velocities across the seats of the PV valves”.

Then why do compnays sell combined PV valves and flame arrestors?

What is the chance of a flame (ignition source) being sucked into the PV valve of a tank?

I suspect more chance of a plane crashing into the tank!

[v8landy]

Anyone???

[v8landy]

Anyone?

[djack77494]

OK, OK. You've successfully solicited a comment, though of uncertain quality. I don't know about the relative speeds of escaping vapors vis-a-vis the flame front that is imagined as taking aim at the tank. I'm of a like mind in suspecting the plane crash scenario is more likely. I know combination flame arrestor/PVSV valves are made and marketed. One would assume they serve some purpose, and I can accept that they will perform as advertised (if in good condition). Personally, I've seen clients attempt to avoid them at all costs. They have small flow passages, and they can corrode or otherwise plug. If there is uncertainty concerning their ability to pass the rated flow when needed, then they are worse than nothing at all. If you buy and install them, I'd recommend good metallurgy for the elements and establish a program to test and maintain them.

[v8landy]

Thanks for the reply.

Now I have said that I will get to work tommotow to find a plane in the site!

I agree that they might have use but are more likley to cause problems if (when) they block leading to tank implosion via vacuum

[Qalander (Chem)]

Dear v8landy Hello/Good Afternoon,

Although I would be not Competent enough to comment I believe. Still, its my way.

1) The comment about our Art. is below the decency level kindly abstain. Do keep/maintain noble human values in the forum please, request only.

2) I believe as experienced at my previous employers and contained in one of my previous replies; the flame arrestor& PVRV combination at times restricts flow both ways and may also play contributory role in over pressurization of tanks etc.

Best regards
Qalander