general physics of equipment.....

[mpittman]

You did and I missed it. More paragraphs would help my old eyes, but I should have seen it anyway.



Regards,



Tobin

i have this really nasty habit of abusing the written english language , and just typing things the way i see em in my head without regard to punctuation , or proper composition )

 

[MarkH]

would it not be fairly simple to build (or modify an existing) sort of first stage regulator and a small low pressure bottle say the size of a can of pop install them on whatever housing your building , and have the regulator feed air into the housing to equalize the inside pressure to that of the ambient pressure outside , and a small overfill valve to bleed off the internal pressure on ascent?

I don't know about DPVs, but this idea was pretty much the norm way back when (50's, 60's) with regards to camera and motion picture housings. Most housings were either home-made or custom- made by pros and they had the cylinder/regulator pressure compensation gadget. Even made-out-of-wood-in-the-garage style housings had a schrader valve to pressurise the housing before going under. As for the flexible chamber compensating idea, I used to have a EWA-MARINE flexible bag-type camera housing that I used down to 80 feet. They're all old ideas that were more or less rejected because you can't beat the simplicity and reliability of the o-ring (though with divers going deeper all the time, pressure resistance isn't as simple as it used to be). Sorry I don't have any input on the DPV scenario, but I don't know much about how they're made to be any help.