Oxygen Fill Whip Needle Valves - Suppliers

[Mr Carcharodon]

Where's a good place to get fill whip needle valves?

I'm looking for brass, Cv~0.2, 1/4 MNPT, and oxygen compatible materials, from someone like Parker or Swagelok that has published specs.

 

[aHeavyD]

Northeast scuba has them.
Needle Valve - O2 - Male to Male - Northeast Scuba Supply

 

[Mr Carcharodon]

Have you used that one and are happy with the flow rates? They do not list much in the way of specs so it is hard to evaluate, but first hand experience is valuable.

 

[aHeavyD]

I have one on my portable fill wip, It works fine.

 

[Mr Carcharodon]

Thanks for the reply.

 

[divingtactics]

I have the one from Northeast Scuba too but found as have friends with them that they are very tight under pressure. This is due to the type of packing they use. Flow rates are fine but they are not the nicest to use. In the end, I swapped it out for a Hoke one and it is magic. If cost is an issue, go with the brass one from NESS, if you want it to work nicely, go with a SS one from HOKE, Swagelok, Parker etc.

 

[Mr Carcharodon]

What was the part number for the Hoke?

I was leaning twords brass due to its higher thermal conductivity.

 

[Mr Carcharodon]

The 1700 series Hokes look promiseing. But where to get one.

 

[divingtactics]

All mine are 3732M4Y. I got them off eBay brand new for a fraction of the new price.

In my opinion, you shouldn't be filling so fast that thermal conductivity is even an issue. For an oxygen fire, you need oxygen, dirt and velocity. The biggest contributor is velocity to an oxygen fire. I have done tests with pure oxygen, oil and high pressure but without gas velocity, I haven't been able to start a fire. Add some gas velocity and boom.... Of course, no one should try this and this is just all my opinion.

 

[Mr Carcharodon]

You did tests where you tried to start a fire? Wow. So...what did you do exactly?

The high conductivity materials are relatively good a at keeping local temperature down (which is rather like reducing the velocity). That may be a belt and suspenders approach. The 1700 series Hoke valves have a Cv of ~0.3 when fully open which would limit heating, and they put the lubricated threads outside of the oxygen rich part of the valve. But again if there is a better choice of valves out there that would be good input.