Preventing Needle Valve Damage

[GDHLEWIS]

As stated above, in a fill panel, you should only have a needle valve if you are doing partial pressure filling to control the oxygen and/or helium. They should be used in conjunction with line valves which are the soft-seat valves mentioned above and those provide more than adequate flow control from the banks. 2 years of regularly use of a needle valve sounds about right if they are being misused as they are in this implementation.
Send pictures of the panel, but I'm 99% sure they should/could be replaced with either a 1/4 turn ball valve or a soft-seat line valve which will last about a decade with heavy daily use. The line valves are functionally identical to the valve in the scuba tank for reference.

This is the panel in question with the leaking valves highlighted. I was speak to a person last night who is more knowledgeable on these things than I (not hard tbh). He suggested the left valve be replaced with flow valves and keep the needle valve for the middle valve. Not a clue, took this position as no one else in the dive club would do it....someone's got to do it so figured it was a good way to learn something new

 

[tbone1004]

View attachment 786854
This is the panel in question with the leaking valves highlighted. I was speak to a person last night who is more knowledgeable on these things than I (not hard tbh). He suggested the left valve be replaced with flow valves and keep the needle valve for the middle valve. Not a clue, took this position as no one else in the dive club would do it....someone's got to do it so figured it was a good way to learn something new

Couple of options, the way I would do it is to put the needle valves right at the valves of the cascade bottles and replace all 5 valves with line valves. You could also put fixed flow restrictors, but you already have the needle valves and just need to rebuild them so I would put them behind the panel somewhere where they become a set it and forget it. Use the line valves for everything else.
You could also replace the 4 needles with a line valve and leave the needle valve for final flow control but that one will still need regular replacement as it is not designed to be opened and closed regularly.

 

[rjack321]

Some ideas...
1) Remove the "open vs close" stickers and replace with "fast and slow"
2) Use a much smaller diameter needle valve knob to deny users any leverage at all to close it tight. Something like an 8mm bolt sized "knob"
3) Put a bushing or a washer on the stem of the needle valve so even the most ham fisted, supposedly trained user, cannot turn the knob to the point where the needle contacts the seat

You could also just replace the needle valve with an orifice and users would have to put up with the fact that flow rates are gonna be choked as the pressure differences decline.

 

[GDHLEWIS]

Thanks @tbone1004 & @rjack321 great suggestions and will defiantly use a bit of both your suggestions. Highly appreciated