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Still young enough to know everything
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4,001 Posts
Discussion Starter · #1 ·
Yet another question about regulator design - yey!:D

Here goes: When a regulator is dry sealed, like with diaphragm regs like Apex DS4 or piston like Sherwood SR1, is the dry chamber equalized with the rest of the first stage so that it will always resist the pressure of the water, or will it get to a certain depth (even if that is really deep) and go pop, and suddenly your dry chamber isn't so dry anymore?

:D
 

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Squidgey Member
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2,151 Posts
If it has a sealed air cavity it will go pop eventualy (realy deep) ? Other than that I dont know.
How about phoning Apex UK and asking, like you were told to do the other day?
Phone a freind, 50/50, Ask the audience. ? :D
 

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Still young enough to know everything
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4,001 Posts
Discussion Starter · #5 ·
If it has a sealed air cavity it will go pop eventualy (realy deep) ? Other than that I dont know.
How about phoning Apex UK and asking, like you were told to do the other day?
Phone a freind, 50/50, Ask the audience. ? :D
I don't like phoning people - I talk too fast and get confused with myself :confused:
 

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PMs are being edited
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9,612 Posts
How about depths we don't dive to?:)
Who knows? Apeks would only test them to a certain depth, and certain standard, something like BSEN250 probably;)
Iain/HSM is the guy on here to talk to about regs designed for silly depths.

I am now wondering if regs get tested to destruction (ie. till the seat fails). Hook it up to a machine and allow the machine to 'breathe' off the reg for hours/days/weeks on end, until something dies??

Dammit James, your inquisitive behaviour in contagious:)
 

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So raise your hand if you think that was a Russian
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11,158 Posts
Both regs, although different, dry seal based on the sealed chamber being close/identical to ambient pressure. for there to be an imbalance big enough to cause a rupture of the dry seal, you'd need to be at a depth where the pressure is greater than the cylinder pressure. So 200m would be 21 bar. If you were at 200m with 21 bar in your cylinder, then a rupture of the dry seal would be the least of your worries ;)
Finally both reg would still work if the dry area was flooded - an Apeks US4 is a DS4 without the seal and pressure transmitter.
 

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Jesus don't want me for a sunbeam
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13,407 Posts
The diaphragm on an Apeks 1st stage is sealed at atmospheric pressure. If you take the cap off and turn the air on nothing happens, if it was equalised then there would be some sort of escape of air but there isn't (if there was then you'd never be able to adjust the IP as that's where the adjusting screw is).

However... it's not that simple... There is a piston beneath the diaphragm. Outside water pressure is transmitted down the piston to the guts of the reg where it is resisted in turn by a spring so technically the forces on both sides of the diaphragm are equal.
 

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So raise your hand if you think that was a Russian
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11,158 Posts
Ok, some homework ;), have a look round the 'net for an apeks 1st stage schematic.
Part number 5 is the 'real' diaphragm, part no. 28 is the cover. When the cylinder valve is opened, part 5 'puffs up' causing a rise in pressure in the dry chamber, this 'in turn puffs up part 28. :)
 
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