Valve puzzle

[Coelacanthic]

I have come accross something that does not gel.
During my attempts to repair 2 cylinder valves, I come accross what I though was a way to blow down the cylinder after the valve stem had been snapped off.
There was a 45 degree appature in the body where the bonnet nut screws in.
After much persuasion, I managed to unscrew the nut. I found the bonnet nut was not drilled. Further investigation led to the discovery that the bonnet nut sealed at the base onto a copper washer so pressure would not be released.
Opening the 2nd valve, to salvage spare parts, the same situation was found.
Asking around, led to incredulous reception.
A logical explanation was given by the commercial diver who gave me the valves.
Maybe it was a way to release pressure on a misfunctioning valve without a person's body being subjected to parts being shot about by the high pressure.
It seems that experience counts for more than the self anointed, equipment scrapping experts.
Also, what make are the valves.
The shown valve is the scrapped on. DIN thread squashed.
Any ideas?

 

[Jimchris]

Sanosub(blue steel, and oms) is the only manufacturer that comes to mind where I have seen that feature.

 

[captain]

Seems removing the bonnet nut and broken stem and using a screwdriver to crack open the valve is the simplest way.

 

[Coelacanthic]

Sanosub(blue steel, and oms) is the only manufacturer that comes to mind where I have seen that feature.

Many thanks, at least I am not totally in my dotage. It is incredible how many valves have had the shaft snapped, (from being hit on the handwheel, torque by trying to open the seized valves, or use of a spanner on a non supported DIN.) Many PCP users.

 

[Coelacanthic]

Seems removing the bonnet nut and broken stem and using a screwdriver to crack open the valve is the simplest way.

Unfortunately many users actually understand the basic workings of their equipment. When I discuss this with many commercially trained divers, the reply is there is no point as they can take it to the LDS. Next they will write a cheque, and expect the dive operator to do the dive and take a video to show how it went!!!!!!

 

[Jimchris]

Seems removing the bonnet nut and broken stem and using a screwdriver to crack open the valve is the simplest way.

Slightly loosening the burst disc cap (If valve is equipped with a burst disc) to the point of a slight leak is another method to drain the cylinder. The disc would need replacement if the valve is still usable after inspection.

 

[Coelacanthic]

I am back to fighting with valves!
This time I wish to replace a Poseidon parallel thread valve with one with a removible insert.
The problem is that it is not a M25. I thought it could be a 3/4 BSP or NSPM. Poseidon Sweden informs me that they only made M25s. Would there be one that was imperial for USA cylinders? If so what thread is it?