Dolphin formula

[caveseeker7]

An article on the subject by Nevil Adkins can be found on JW Bech's The Rebreather Site at http://www.therebreathersite.nl/how_dolphins_work.htm

 

[SamDiver14]

That is a great site thanks. Have any of you guys ever heard of an upgrade to the Drager unit that would replace the orifice with an adjustable valve? perhaps a needle valve?

 

[caveseeker7]

an upgrade to the Drager unit that would replace the orifice with an adjustable valve? perhaps a needle valve?

Yes and no. Do you mean for cmf SCR operation as is used in the Azimuth?
In that case no, nor do I know if the Azi's valve/switchblock would work. I'm not sure about the exact flow rates of the Azi. Also, that unit uses regular Mares 1st stages rather than the Dräger propriatory high interstage pressure (about 240psi I believe) ones used on the Dolphin. I doubt they would work with Azi valving.

For an excellent desription of the Azimuth visit Diver Dave's Teardown Page:
http://www.nobubblediving.com/azimuth.main.htm

For CCR conversions Tubby downunder uses an adjustable valve rather than the fixed orifice KISS valve that is more popular here in the States.
Another very informative website in many ways: http://www.vk4tub.org/tubby/pagedex.html

 

[SamDiver14]

That is exactly what I had in mind. I think one of the biggest limitations of the Dolphin is the set flow rates through the sonic orifices. In my opion it would be much closer to a perfect SCR if it had a dial in flow rate regulator. I think a needle valve would be the easiest way to achieve a variable flow rate. I would assume that is what the guts of the Azimuth dial in valve is a needle but the page didn't say. Is there a better choice for a variable sonic flow orifice?

Never mind, it does say that it is a needle valve. Although I like the JW Bech site much better for its discussion of sonic flow orifices and the flow dynamics.

 

[JPBECK]

Hey Caveseeker--have you spoke to Wayne Miller lately--- He and Dave Forsite (sp?) have made electronics to make any SCR a computer driven CCR---- I am waiting on mine, still in the beta mode--

If you dont know who I am talking about sorry I am mistaken on your identity.

Later~

 

[caveseeker7]

Joe, haven't talked to Wayne in ages. When he was still going forth and back between his new place and Riverside I mailed him every once in a while, but since he closed down I haven't heard from him.

I remember him talking a bit about the electronics when I did my Inspiration intro. Back than it was still in the planning stages.

I wonder if he'll be at the Scuba Show, maybe if ANDI has a booth again ... .
I'll look out for both, would be good to see him again.

Stefan

 

[JPBECK]

He didnt go-- but if you want his e-mail pm me and I will give-- nice talking to you again!