Repair my mini-IPG?

[Pearlman]

And so I dropped my mini IPG from a height - one that I had purchased newly. Before dropping it the readings were almost a perfect match with my 4” IPG now the needle does not rest at zero and the readings are off by +6psi. So when my 1st stage reads 9.5bar it shows just a hair above 10bar.

How do I reset the needle back to zero? I don’t want to do mental arithmetic on the boat and convince myself the gauge is perfect otherwise (you never know if it goes further off-calibration secretly). I want to be able to match the gauge with my larger 4” version when I’m checking and packing my gear before each trip…

 

[davehicks]

Buy a new one, and get a sleeve to protect it.

 

[axxel57]

Normally it's no big deal to repair those IP meter if you can remove the glas and the ring, which usually is not difficult ( in contrast to SPGs).
The indicator is often just sticked on the 'needle', so either you can just take it off and put it on again on zero, or you just bend the indicator counterclockwise until it moves in the right direction a bit ( take care when you lift the indicator over that little post).
The indicator has just 'moved' on the 'needle' a bit, the tube inside the IP meter can hardly be damaged by a shock caused by a fall.
You have to be careful with the indicator, because if you do it too much, you have the same situation just in minus territory.
Anyway, you will find out how it goes, I have 'repaired' many IP meters, it's easier than you probably think......

Good luck!

 

[Pearlman]

Turns out the front pane is just plexiglass with a screw on/off just like a jam bottle lid! ( It’s not an underwater item so makes sense! ) Now I have access to the needle, but applying gentle pressure to force it down isn’t working - a coil spring appears to be in action. Looks like it has jumped a gear tooth in the internal mechanism? I’m afraid I’ll break it if I apply too much force.

I’ll just take it to a local repair shop maybe…

 

[Sascha314]

Well I would buy a new one. Yes more expensive, but it could also be crooked, so actually it may not be only an offset but a different "correction" depending on the current value. It is a measurement device and after the offset repair you would need to test and calibrate it. Not sure if thats worth it.
Remember: There is some intrinsic uncertainty in each measurement device.

 

[axxel57]

Turns out the front pane is just plexiglass with a screw on/off just like a jam bottle lid! ( It’s not an underwater item so makes sense! ) Now I have access to the needle, but applying gentle pressure to force it down isn’t working - a coil spring appears to be in action. Looks like it has jumped a gear tooth in the internal mechanism? I’m afraid I’ll break it if I apply too much force.

I’ll just take it to a local repair shop maybe…

Yes, of course you work against a 'coil spring', that's the 'snail tube' ( Bourdon Tube) which straightens when air pressure gets in it.
Can't you pull off the indicator?
There is nothing to calibrate but the indicator to the right position, seems you don't know how these devices are working.
If that 'repair' is too complicated for you, why you not just go on using the IP Meter as it is, calculating the difference into your measurement?
Very sure the basic mechanism ( the Bourdon Tube) has not been damaged........

 

[Pearlman]

Well I fixed it now. I was confused about what you called an indicator - the needle I guessed later. I just pulled out the indicator/needle with a mini pliers when it was pressurised and aligned it to match the needle of my larger 4” IPG. Now they are both in sync as before. Thanks. I did review a video of how it works earlier today


But it feels like a hack because something internally has jumped off its original setting by 5-6 psi…

Edit: or maybe the connecting link mechanism (as seen in video) just got rotated on its own axis upon impact?

 

[axxel57]

Why didn't you just zero the needle in the IPG unpressured?

 

[Pearlman]

Why didn't you just zero the needle in the IPG unpressured?

I tried that at first, but it showed the same error… maybe it was just a fluke mistake in how I set it at first few tries … and by the time I set it to 140 psi my hand-eye coordination got practiced and better?

 

[Pearlman]

Thinking again, from a purely process perspective - We want to always reattach the pointer (using the correct terminology now instead of indicator/needle) under pressure - because unpressurised Zero is not a reference point. When testing accuracy - We need to match different IP values of this gauge (if you have multiple 1st stages at hand) to the reference gauge readings under pressure. Although quite likely that one would set ones multiple 1st stages to almost the same IP if self-servicing at home … but in theory pressure readings are the benchmark, not the Zero reading…

Just ruminating and over-thinking as usual …