SeaJay
Contributor
HP seats are vulnerable whether the first stage is of the diaphragm design or of the piston design.
The valve seats inside your second stage are vulerable as well. Simply put, a gradual pressurization on both (actually three if you've got two second stages, or a second stage and an "octo") is better in terms of "wear and tear" than the instant-pressurization of a diver opening a valve quickly. This can be accomplished by continuously purging one second stage when opening the tank valve.
That's all there is to it - no matter what the design, gradual opening is "gentler" on valves and seats than quick opening.
Some Poseidon regulators and other "upstream" types may not be affected quite the same way as your standard downstream (Mares, Atomic, SP, Aqualung, Apeks, etc.) regulators - but rest assured, "gradual opening" is recommended by all regulator manufacturers.
A regulator that's not pressurized suddenly being filled with 3000 psi sorta "slams" the valve into it's seat - closing it quickly, and causing a little divot in the seat over many repetitions. Your valve and valve seat are going to get this way anyway - that's why they're replaced during service. However, gently pressurizing the system will tend to save wear and tear and prevent premature wear (which 50 dives probably is).
Still, though - "premature wear" is not the leading reason why you'd want to open your valve slowly, and while pressing the purge button - it serves double-duty to reduce heat within the first stage during pressurization, which is very small in size (about the size of the head of a pin) and very quick (lasting only a fraction of a second) but can be very hot. The first stage can handle it (and doesn't even warm to the touch in the amount of time this occurs) but... Well... You're adding pressurized oxygen (present even in air, but especially dangerous in high O2 mixes), fuel (any O-ring, molecule of compressor oil, or hydrocarbon is fuel and will burn), and heat... A bad scenario in terms of "boom."
What typically happens during combustion in this case is that the valve itself can explode - both the pressure relief (bolt or disk) and the valve knob will pop off, becoming high speed shrapnel. If there's a high (>40%) O2 percentage in the tank as well, the whole thing could easily become a bomb. You don't want this.
...Anyway, the point is that all of this could be avoided with the simple practice of opening valves slowly while purging. Oh yeah... And keep your hand wrapped AROUND the knob, instead of over the end of it - just in case. Count the missing fingers on older divers' hands if you don't believe me.
It astounds me that the industry teaches the concept of "O2 clean," and apparently stresses it to a degree that some shops won't fill tanks without this certification - but then fail to teach the simplest, safest methods for maintaining safety in the presence of pressurized gasses.
Most shops I've been to look at oxygen and hyperoxic mixes as "dangerous" or "things to take extra care around" - yet, it's not the oxygen that they need to be afraid of. It's a lot of gas - any gas - under a lot of pressure that they have to watch out for. To me, it's like they're playing in the street during rush hour - thinking that the cars around them are "dangerous" because they've got gasoline in them.
They're missing the point.
Purge. Open the valve slowly. Stay out of the street.
The valve seats inside your second stage are vulerable as well. Simply put, a gradual pressurization on both (actually three if you've got two second stages, or a second stage and an "octo") is better in terms of "wear and tear" than the instant-pressurization of a diver opening a valve quickly. This can be accomplished by continuously purging one second stage when opening the tank valve.
That's all there is to it - no matter what the design, gradual opening is "gentler" on valves and seats than quick opening.
Some Poseidon regulators and other "upstream" types may not be affected quite the same way as your standard downstream (Mares, Atomic, SP, Aqualung, Apeks, etc.) regulators - but rest assured, "gradual opening" is recommended by all regulator manufacturers.
A regulator that's not pressurized suddenly being filled with 3000 psi sorta "slams" the valve into it's seat - closing it quickly, and causing a little divot in the seat over many repetitions. Your valve and valve seat are going to get this way anyway - that's why they're replaced during service. However, gently pressurizing the system will tend to save wear and tear and prevent premature wear (which 50 dives probably is).
Still, though - "premature wear" is not the leading reason why you'd want to open your valve slowly, and while pressing the purge button - it serves double-duty to reduce heat within the first stage during pressurization, which is very small in size (about the size of the head of a pin) and very quick (lasting only a fraction of a second) but can be very hot. The first stage can handle it (and doesn't even warm to the touch in the amount of time this occurs) but... Well... You're adding pressurized oxygen (present even in air, but especially dangerous in high O2 mixes), fuel (any O-ring, molecule of compressor oil, or hydrocarbon is fuel and will burn), and heat... A bad scenario in terms of "boom."
What typically happens during combustion in this case is that the valve itself can explode - both the pressure relief (bolt or disk) and the valve knob will pop off, becoming high speed shrapnel. If there's a high (>40%) O2 percentage in the tank as well, the whole thing could easily become a bomb. You don't want this.
...Anyway, the point is that all of this could be avoided with the simple practice of opening valves slowly while purging. Oh yeah... And keep your hand wrapped AROUND the knob, instead of over the end of it - just in case. Count the missing fingers on older divers' hands if you don't believe me.
It astounds me that the industry teaches the concept of "O2 clean," and apparently stresses it to a degree that some shops won't fill tanks without this certification - but then fail to teach the simplest, safest methods for maintaining safety in the presence of pressurized gasses.
Most shops I've been to look at oxygen and hyperoxic mixes as "dangerous" or "things to take extra care around" - yet, it's not the oxygen that they need to be afraid of. It's a lot of gas - any gas - under a lot of pressure that they have to watch out for. To me, it's like they're playing in the street during rush hour - thinking that the cars around them are "dangerous" because they've got gasoline in them.
They're missing the point.
Purge. Open the valve slowly. Stay out of the street.
