Tank pressure gauge without hooking up a regulator -- most accurate?

[Crass3000]

Looking to get a tank pressure guage so that I don't have to hook up a regulator to see what the pressure on all my tanks are.

Looks like you can get a set that has a DIN guage with a DIN to yolk converter so that you can check the pressure on either type of tank valve.

I want to buy the most accurate guage so I'm hoping the people with experience with these can let me know which one's work the best. If you work in a shop and have seen the accuracy on some of these or just happen to have one and feel it has good or bad accuracy please let me know. I can't afford to waste money so I only want to buy this once.

Thanks for any input,
Mike

 

[tbone1004]

The DGX ones are fine. They are much more accurate than the SPG's themselves. These are all standard industrial pressure gauges so they're pretty spot on. They are also standard 1/4" NPT fittings so you can swap the gauges out if you decide you want to go digital or whatever. The important bit is getting the "fill adapter" part and then you can put whatever you want on the end of it

 

[kwinter]

I can't really speak to which ones are more accurate because you need to have a good standard to measure against. But all the ones I used have been fairly precise. There's a difference.

 

[rhwestfall]

I have one from XS Scuba. Oil filled gauge. Fits my needs quite well.

 

[cool_hardware52]

I remember when a "tank checker" was the only gauge we had…..

Tobin

 

[spoolin01]

If you only want to buy once, I'd say the best gauge is the one that's built for durability, and doesn't drift over its life span. You can always work with an accuracy offset, once you know it. As kwinter indicated, precision/repeatability is easier to come by than accuracy, and it's more practical. I don't even know if most SPGs can be adjusted, many pressure gauges can't. So unless the manufacturer ruthlessly culls for accuracy, you're stuck with precision and durability as the primary quality indicator.

Best to check against other gauges for a consensus perspective - or pay a calibration service to give you an offset value. You'll have to repeat either periodically if you want confidence the value is still applicable.

 

[tbone1004]

you're overthinking that far too much...

First issue is the change in temperature, you don't know the internal temp of the air when you're checking the tank right after filling, and you would have to adjust ambient vs water temp, then factor in any thermoclines etc.

Remember that pressure gauges have a working pressure of around 75% of their listed value, so when you have full HP tanks, they are at the upper end of their working limit so you will only have so much accuracy unless you want to pay a lot more for higher pressure gauges. The 5000psi's are very accurate in the $30 range, +_1.5%, so basically half the marked accuracy which is in 100psi increments. If you want any more accurate than that without getting enormouse gauges you have to go digital which is big bucks *$300 minimum*.

https://www.divegearexpress.com/accurate-cylinder-pressure-checker
For $40 that is certainly good enough. If you want more accuracy get a better gauge, but the variables mentioned above mean that you can't actually predict what the tank is going to do, combined with the fact that our SPG's are +_ 50psi. If you are partial pressure blending for VERY deep trimix blends where 50psi matters, then you pretty much have to go digital, anything other than that is just being anal

 

[cool_hardware52]

If you are partial pressure blending for VERY deep trimix blends where 50psi matters, then you pretty much have to go digital, anything other than that is just being anal

Even then it's far more important the blender understands the quirks of the fill station, and has a good feel for the Odd behavior of Helium and the effects of temperature, ambient and the delta T due to compression.

Tobin

 

[Bob DBF]

I remember when a "tank checker" was the only gauge we had…..

Tobin

...and it only went to 3000#


Bob

 

[spoolin01]

you're overthinking that far too much...

First issue is the change in temperature, you don't know the internal temp of the air when you're checking the tank right after filling, and you would have to adjust ambient vs water temp, then factor in any thermoclines etc.

Remember that pressure gauges have a working pressure of around 75% of their listed value, so when you have full HP tanks, they are at the upper end of their working limit so you will only have so much accuracy unless you want to pay a lot more for higher pressure gauges. The 5000psi's are very accurate in the $30 range, +_1.5%, so basically half the marked accuracy which is in 100psi increments. If you want any more accurate than that without getting enormouse gauges you have to go digital which is big bucks *$300 minimum*.

https://www.divegearexpress.com/accurate-cylinder-pressure-checker
For $40 that is certainly good enough. If you want more accuracy get a better gauge, but the variables mentioned above mean that you can't actually predict what the tank is going to do, combined with the fact that our SPG's are +_ 50psi. If you are partial pressure blending for VERY deep trimix blends where 50psi matters, then you pretty much have to go digital, anything other than that is just being anal

Not sure if this was in response to my post, but I understood the OP to be looking for a tank checker, so temp differences wouldn't likely factor in, particularly if his real objective is simply comparing the status of the tanks in his collection. If it's really max accuracy he's on to for some inexplicable reason, then he'd have to be mindful of temp as a variable, along with the other considerations necessary to infer accuracy in the dial read-out.

I don't know how dependent the read out on these consumer pressure checkers is to temp or position along the dial range (not sure exactly what you meant by the 75% part but assume you were citing non-linearity), but for the most part I simply wanted to make the point that accuracy would not be the top characteristic in need of "best" in this context.