Warning you caught me before coffee so this may be a bit blunt. It is all typed respectfully.
How do you know that particular valve is rated for 2000 PSI? I do not see it anywhere on the website.
The sites Description:
1/4" BBV4 FEMALE NPT BRASS NEEDLE VALVE, 2000 PSI MAOP
, 300 DEG F MAX TEMP, BRASS BODY/SEAT, PTFE PACKING
"Maximum allowable operating pressure or MAOP refers to the wall strength of a pressurized cylinder such as a pipeline or storage tank and how much pressure the walls may safely hold in normal operation.
The MAOP is less than the MAWP (maximum allowable working pressure). MAWP being the maximum pressure based on the design codes that the weakest component of a pressure vessel can handle. Commonly standard wall thickness components are used in fabricating pressurised equipment, and hence are able to withstand pressures above their design pressure. Design pressure is the maximum pressure a pressurised item can be exposed to. Due to the availability of standard wall thickness materials, many components will have a MAWP higher than the required design pressure. Relief valves are set at the design pressure of the pressurised item and sized to prevent the pressurised item being overpressured. Depending on the design code that the pressurised item is designed, an overpressure allowance can be used when sizing the relief valve. This is +10% for PD 5500, and ASME Section VIII div 1 & 2 (with an additional +10% allowance in ASME Section VIII for a fire relief case). ASME have different criteria for steam boilers."
I am sorry I can’t Show any more then that, That is what I was going off of... And the guy who found it on a brewing forum.
It is probably safe, but that isn't why we use a needle valve. A CO2 needle valve has to be able to throttle down the gas flow to what would normally be seen as an almost acceptable leak, and be able to adjust that flow +/- 25% or so repeatably. It also has to not leak at all at the valve stem, which is quite difficult to do cheaply. Our needle valves are not at all like that one.
I know why we use it, but I see a lot of Tanks with and on/off switch attached to a needle valve rated for 250 psi. In this situation people are attempting to use the on/off valve as a step down to the needle valve. In general I will not put something that risky at my workplace, I won’t endanger other people. That is not what on/off valves for paintball tanks are used for, without going further into how paint-ballers use different equipment posting a linke to a safe needle valve was easiest… Minus explaining.
Even rated at 5000 it's not safe unless you have a regulator keeping the pressure at a safer level to your post body kit.
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I dis-agree with your reasoning, but agree with the statement. If a needle valve is able to constantly reduce pressure to a point where post body is rated, then it is fine. Plus it depends what is post needle valve, are you talking about bubble counter, diffuser, or the hose? In general you can say none of those can handle 850 psi when the valve fails… but they still can’t do it when the regulator fails. Granted regulator will less likely fail, but what are you trying to convince me of? I have a regulator made for a co2 tank.
Now I am not defending not using a regulator, but what I am saying is you are making an argument that this needle valve is not safe because if it fails, other components will break. Then you are going to have to replace all things with stuff that is safely rated to work under 850 psi. But in a normally seen set-up, if a regulator fails the needle valve will pop.
We can always say something is going to fail, because it will. But having a needle valve that is rated for the pressure I am working with seems like a better bet for me. I will spend the large sum of $8 to have one more component that is over rate for my system.
Man, touchy subject here it seems. I shall not try to post finds in the future. I do have a regulator for my system that is not yet built by the way.