Question Suunto Transmitter Modification, Possible???

[stiebs]

1. only the transducer sees the HP air when the tank valve is opened, instead of the entire transmitter housing.

That's no different to an analog SPG (or any other gauge for that matter). The SPG casing is only subject to ambient pressure, it's only the Bourdon tube inside that is subject to high pressure.

In your transmitter there will be an electronic part similar to this:

This metal casing is subject to high pressure, which enters the inlet and is sealed with an o-ring. There is electronics inside which transmit a signal to the pins on the back of the unit. This part is housed within the transmitter casing which, as pointed out, is only subject to ambient pressure.

 

[Zef]

That's no different to an analog SPG (or any other gauge for that matter). The SPG casing is only subject to ambient pressure, it's only the Bourdon tube inside that is subject to high pressure.

In all my years diving I never gave much thought to this. When folks learn to turn the glass face of their SPG away when opening their cylinder valve as a "just in case" measure, I think the majority of divers have the impression that the entire SPG is charge with HP air and never give it much though beyond this.

I am glad I started this thread as it has inadvertently enlightend me on a few things and may provide good information to others about something that is just not really covered in training.

-Z

 

[stiebs]

In all my years diving I never gave much thought to this. When folks learn to turn the glass face of their SPG away when opening their cylinder valve as a "just in case" measure, I think the majority of divers have the impression that the entire SPG is charge with HP air and never give it much though beyond this.

The idea of turning the glass away from you when turn the cylinder on is if there is a failure in the inner mechanism, and there is a leak into the housing of the SPG, then yes, the whole casing will be filled with HP air, and the most fragile part will give way first. If this is the glass shattering, or the face being forced off the body, then that's a pretty dangerous projectile.

Many newer SPGs will have some sort of pressure relief fail-safe at the back (like a small plastic plug) that is designed as a weak point and in a failure will blow before the face does/