Confused about the mechanics of a spg and a practical question as well

[surgeman]

The question arises because of the finding of water in my SPG after a dive.

One instructor was adamant that it must have come from my first stage that must have had water in it after I soaked it last. That had been over a month earlier

Instructor #2 told me that there is no connection between the glass case and the air path from my first stage down to the spg and so it could not be the case and that the most likely scenario was a bad seal. The glass is not cracked as far as I can see.

I would like to understand the mechanics of the SPG for a better understanding of my equipment but on a practical level if it did come from my first stage I need to have my first stage serviced as it would have been filled with water for a month or so.

AS an extra bit of info, when I unscrewed my SPG from my high pressure hose there was some salt residue in the distal end of the thread. and the pin that connects the spy and the hose.

Thanks all

 

[dumpsterDiver]

SPG commonly get water in them. They will work for a few days, but they are ruined. No need to do anything with the first stage

 

[WarrenZ]

Check out the divegearexpress.com spg info page they have a picture of the spg guts. But basically you have a tube that is connected to your HP hose that under pressure straightens moving the needle. Unless this tube is ruptured (read massive air leak) water cannot get from your first stage or hoses into the visible part of your spg

 

[Bob DBF]

I would like to understand the mechanics of the SPG for a better understanding of my equipment but on a practical level if it did come from my first stage I need to have my first stage serviced as it would have been filled with water for a month or so.

Your SPG is shot, buy another one, then take that one apart and take a look. Nothing like taking gear apart to see how it works and no "pressure" to fix it when your done.


Bob

 

[tbone1004]

what Bob said. SPG is gone. If your SPG was functioning properly, Instructor 1 was wrong, and sounds like he's an idiot. If it wasn't functioning properly or at all, it is possible but unlikely.
Instructor 2 is correct in that the glass seal is likely the culprit.

https://www.divegearexpress.com/spg
Watch the video at the bottom

 

[agilis]

An analog SPG functions like a tiny version of an old fashioned butcher's scale to an astonishing degree. Instead of weighing chopped meat the spg's mechanism is 'weighing' the air pressure coming out of that small HP hole in the first stage.

 

[surgeman]

Thanks all, very helpful and now I have a better understanding of the process.

 

[dumpsterDiver]

[video=youtube;37mFHPhnxQ4]https://www.youtube.com/watch?v=37mFHPhnxQ4[/video]