placement of adv...

whoizrob

Is there any reason why the ADV needs to be placed high in the loop nearer to the divers head rather than elsewhere on the rig?

I'd venture to guess that if the diver were in a heads up position the water column would exert more pressure onthe ADV casuing it to be more prone to freeflow. You'd have to crank up the ADV to prevent that and I'd guess the downside would be increased effort trying to get it to crack. Is this the only reason? Would have a pneumatically balanced reg help with this issue?

Thanks!

Rob

jaap

If I understand you correctly I think you got it the wrong way around.
If the ADV is to low inside the loop the ADV-membrane will be more likely to experience a negative pressure in relation to the water pressure and push the lever that opens the flow of gas into the loop. This is not good and a big waste of gas if it leads the ADV to flow gas into the loop on every inspiration even though the loop still has enough gas for normal breathing.

This is why pretty much all Rebreather designed for UW use with an ADV has it mounted high or near the center of the loop.

whoizrob

I figured it would crack more easily. What I was referrencing was that to counteract this one should increase the cracking resistance of the ADV. I don't mind locating the ADV higher in the loop I was just playing with an idea for a design I have... Thanks =)

Rob

Marc T

Its VERY interesting to have a close look to the "ADV system" of a Rebreather 80 ( and other clones ) its the only system I know witch instantly freeflow when you loose your mouthpiece but dont overfill your loop even if the confort is not good in vertical position it doesnt add more gas, the pressure increase untill your again in horizontal position but no free flow.
Less confort but big security.
Thats the reason I stay one more time on EDOO4 even if turned in mCCR.
Have a look to
Swiss Technical Diving Equipment