Draeger Dolphin gas system

divetheworld · 20th June 2007, 20:40

Quote: (Originally Posted by camerone)

If you are using this piece for a homebuilt, there are three points to keep in mind:

The whole unit is designed to operate from the Drager first stage, which supplies a significantly higher IP to the dosage unit. Putting a standard first stage will cause the bypass (ADV) part to not function properly. You can change the spring out, however, and make it work.
The CMF part is also designed to be run off of a higher than normal IP in order to achieve sonic flow at normal operating depth. Using the Drager orifice with a normal first stage to achieve CMF is not the proposition you might think it is... the better solution is to buy, from TecMe, the right fitting for the block that's just a pass-thru hole, then use an external kiss-style valve and restriction; you can still route through the dosage block, which is very convenient.
The Drager first stage is designed to creep a bit, as a fail-safe mechanism. IP will rise until the point where it _will_ fire the ADV portion, which is different than a normal first stage (er, a working one, anyway) which is used with a demand regulator. The Drager first is supposed to ALWAYS be injecting gas through at less the sonic flow orifice.

Sonic flow is not the same as putting a restriction in line with the gas injection...be sure you're clear on what you're doing if you decide to go with the Drager block.

Thats all the most important, fundemental operational characteristics of the Dolphin gas system.
One I would add that some may not know is there is another safety mechanism built in. The dosage units actually have two orifices built in which each share the gas flow requirments. This means that if an orifice blocks, the FO2 will not encounter such a dramatic drop.

Nice info huh? C'mon, read between the lines. If you block one orifice, you halve the flow? custom flow rate units!!! Whats half the 100% jet flow?
I'll leave you to contemplate that.

Brent

gibbogeo · 21st June 2007, 00:02

Quote: (Originally Posted by divetheworld)

Whats half the 100% jet flow?

Are you sure that the 100% orifice have two rubies?

robertfondren · 22nd June 2007, 10:30

See, I'm not necessarily adverse to the idea of a true Draeger first stage, but I know that @ some point I will definately not wish to be bound to the reverse-din fittings/ interfaces. Perhaps the industrious Martin@tecme has everything I need.

**Freef** · 22nd June 2007, 14:42

Quote: (Originally Posted by divetheworld)

Nice info huh? C'mon, read between the lines. If you block one orifice, you halve the flow? custom flow rate units!!! Whats half the 100% jet flow?
I'll leave you to contemplate that.

7.6 L/min.

Half of 100% is 50%, the 50% jet gives a flow of 7.6 L/min, therefore that's what you'll get if you block one of the 100% jets.

Bosh · 22nd June 2007, 15:54

Whether the 100 % jet has 1 or 2 rubies was discussed a while ago.

What id like to point out is that nobody needs 2 rubies in a 100 % jet !!
Assuming one follows "safe operation of a pure O2 rig".

If you dive on pure oxygen, and flush the loop before diving, all nitrogen(inert gas) will come from yourself. That amount is negligable.

If the jet blocks the ADV will supply the loop with fresh pure oxygen.

Even if the ADV fails "all" that will happen, is you breathe down the loop volume without going hypoxic, once the loop is small enough one is bound to notice

There are pure O2 rigs on the market that has an ADV only, no jets whatsoever. Poseidon if i remember correct.

Having said that id like to say that O2-monitoring is a very good idea on any rebreather.

Best regards

Bo

divetheworld · 22nd June 2007, 20:40

Quote: (Originally Posted by Freef)

7.6 L/min.

Half of 100% is 50%, the 50% jet gives a flow of 7.6 L/min, therefore that's what you'll get if you block one of the 100% jets.

Not the right answer mate, good shot though!
Tech specs in the table at the bottom of the page in the link below.

Dräger Dolphin Dosiereinheit 100% O2 - W+S Water Safety Europe GmbH - Online Shop - Seit 1999

caver99 · 23rd June 2007, 08:50

Hi,

the orifice-flow calculations are a bit strange......

1. O2 Draeger Orifice (Dolphin) has only one ruby (normal flow on Draeger first satge around 2 l/min)

2. on all other jets, there are two orifices BUT there are normally never two with same flow (alone) inside.

So you never know, unless you check, what flow you have when you block one orifice.
It is possible that one gives you 2 l/min and the other 3,5 l/min (for the 60% jet with overall flow of around 5-5,5 l/min)
Or both give you around 2,5 l/min......or....

As far a I know, even Draeger is bulding the jets (let them built..) by try and measure....and then they are labled for the flow range

Also some Dolphin units are delivered with 13-14 bar IP, some up to 16 bar IP.

Modifying the Dolphin stage and the Dolphin jets is easy and possible, but only if you now what you do and when you can check it! So take care.

Martin

dive safe ...with no bubbles

**Freef** · 23rd June 2007, 20:43

Quote: (Originally Posted by divetheworld)

Not the right answer mate, good shot though!

I hope people realise that I am Urine Extraction specialist and not a complete idiot...errr, too late for that...

20th June 2007, 20:40	#11 (permalink)
divetheworld Dive porn pimp Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Classic Kiss Other CCR Join Date: Mar 2005 Location: Leeds, England Posts: 1,619	Re: Draeger Dolphin gas system Quote: (Originally Posted by camerone) If you are using this piece for a homebuilt, there are three points to keep in mind: The whole unit is designed to operate from the Drager first stage, which supplies a significantly higher IP to the dosage unit. Putting a standard first stage will cause the bypass (ADV) part to not function properly. You can change the spring out, however, and make it work. The CMF part is also designed to be run off of a higher than normal IP in order to achieve sonic flow at normal operating depth. Using the Drager orifice with a normal first stage to achieve CMF is not the proposition you might think it is... the better solution is to buy, from TecMe, the right fitting for the block that's just a pass-thru hole, then use an external kiss-style valve and restriction; you can still route through the dosage block, which is very convenient. The Drager first stage is designed to creep a bit, as a fail-safe mechanism. IP will rise until the point where it _will_ fire the ADV portion, which is different than a normal first stage (er, a working one, anyway) which is used with a demand regulator. The Drager first is supposed to ALWAYS be injecting gas through at less the sonic flow orifice. Sonic flow is not the same as putting a restriction in line with the gas injection...be sure you're clear on what you're doing if you decide to go with the Drager block. Thats all the most important, fundemental operational characteristics of the Dolphin gas system. One I would add that some may not know is there is another safety mechanism built in. The dosage units actually have two orifices built in which each share the gas flow requirments. This means that if an orifice blocks, the FO2 will not encounter such a dramatic drop. Nice info huh? C'mon, read between the lines. If you block one orifice, you halve the flow? custom flow rate units!!! Whats half the 100% jet flow? I'll leave you to contemplate that. Brent __________________ Attitude and self praise is no reccomendation. Dont try to be a great man, just be a man and let history be the judge of you. *WWW.NARKEDAT90.CO.UK* *http://www.grpservices.com/pursuit/* Supporting Shearwater Research Products in Europe
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21st June 2007, 00:02	#12 (permalink)
gibbogeo Gilberto Bonaga, Italy Current Rebreather/s: Classic Kiss Dolphin Home Build Other Rebreather/s: Dolphin Home Build Join Date: Sep 2005 Location: italy Posts: 326	Re: Draeger Dolphin gas system Quote: (Originally Posted by divetheworld) Whats half the 100% jet flow? Are you sure that the 100% orifice have two rubies?
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22nd June 2007, 10:30	#13 (permalink)
robertfondren New Member Current Rebreather/s: Ray Other Rebreather/s: Not Bought Yet Ray Join Date: Mar 2006 Location: u.s.a. Posts: 88	Re: Draeger Dolphin gas system See, I'm not necessarily adverse to the idea of a true Draeger first stage, but I know that @ some point I will definately not wish to be bound to the reverse-din fittings/ interfaces. Perhaps the industrious Martin@tecme has everything I need.
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22nd June 2007, 14:42	#14 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,405	Re: Draeger Dolphin gas system Quote: (Originally Posted by divetheworld) Nice info huh? C'mon, read between the lines. If you block one orifice, you halve the flow? custom flow rate units!!! Whats half the 100% jet flow? I'll leave you to contemplate that. 7.6 L/min. Half of 100% is 50%, the 50% jet gives a flow of 7.6 L/min, therefore that's what you'll get if you block one of the 100% jets. __________________ David. Diving the mahogany rebreather.
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22nd June 2007, 15:54	#15 (permalink)
Bosh New Member Current Rebreather/s: Dolphin Other Rebreather/s: Not Bought Yet Dolphin Join Date: Dec 2006 Location: Denmark Posts: 41	Re: Draeger Dolphin gas system Whether the 100 % jet has 1 or 2 rubies was discussed a while ago. What id like to point out is that nobody needs 2 rubies in a 100 % jet !! Assuming one follows "safe operation of a pure O2 rig". If you dive on pure oxygen, and flush the loop before diving, all nitrogen(inert gas) will come from yourself. That amount is negligable. If the jet blocks the ADV will supply the loop with fresh pure oxygen. Even if the ADV fails "all" that will happen, is you breathe down the loop volume without going hypoxic, once the loop is small enough one is bound to notice There are pure O2 rigs on the market that has an ADV only, no jets whatsoever. Poseidon if i remember correct. Having said that id like to say that O2-monitoring is a very good idea on any rebreather. Best regards Bo
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22nd June 2007, 20:40	#16 (permalink)
divetheworld Dive porn pimp Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Classic Kiss Other CCR Join Date: Mar 2005 Location: Leeds, England Posts: 1,619	Re: Draeger Dolphin gas system Quote: (Originally Posted by Freef) 7.6 L/min. Half of 100% is 50%, the 50% jet gives a flow of 7.6 L/min, therefore that's what you'll get if you block one of the 100% jets. Not the right answer mate, good shot though! Tech specs in the table at the bottom of the page in the link below. Dräger Dolphin Dosiereinheit 100% O2 - W+S Water Safety Europe GmbH - Online Shop - Seit 1999 __________________ Attitude and self praise is no reccomendation. Dont try to be a great man, just be a man and let history be the judge of you. *WWW.NARKEDAT90.CO.UK* *http://www.grpservices.com/pursuit/* Supporting Shearwater Research Products in Europe Last edited by divetheworld : 22nd June 2007 at 20:44.
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23rd June 2007, 08:50	#17 (permalink)
caver99 New Member Current Rebreather/s: Other CCR Dolphin Azimuth Other SCR Home Build Other Rebreather/s: Not Bought Yet Other CCR Dolphin Azimuth Other SCR Home Build Join Date: Jul 2006 Location: Caribbean, Germany Posts: 62	Re: Draeger Dolphin gas system Hi, the orifice-flow calculations are a bit strange...... 1. O2 Draeger Orifice (Dolphin) has only one ruby (normal flow on Draeger first satge around 2 l/min) 2. on all other jets, there are two orifices BUT there are normally never two with same flow (alone) inside. So you never know, unless you check, what flow you have when you block one orifice. It is possible that one gives you 2 l/min and the other 3,5 l/min (for the 60% jet with overall flow of around 5-5,5 l/min) Or both give you around 2,5 l/min......or.... As far a I know, even Draeger is bulding the jets (let them built..) by try and measure....and then they are labled for the flow range Also some Dolphin units are delivered with 13-14 bar IP, some up to 16 bar IP. Modifying the Dolphin stage and the Dolphin jets is easy and possible, but only if you now what you do and when you can check it! So take care. Martin dive safe ...with no bubbles
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23rd June 2007, 20:43	#18 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,405	Re: Draeger Dolphin gas system Quote: (Originally Posted by divetheworld) Not the right answer mate, good shot though! I hope people realise that I am Urine Extraction specialist and not a complete idiot...errr, too late for that... __________________ David. Diving the mahogany rebreather.
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