Dolphin Flow Rates

GaryB · 20th September 2008, 17:46

I have a question about the flow rates on the Dolphin....

Here's what I'm seeing for flow rates:
32% orifice - 18.25 LPM <- this is a new orifice from Tecme.
40% orifice - 11.9 LPM
50% orifice - 8.25 LPM
60% orifice - 5.8 LPM

The IP is 240 PSI (16.3 bar).

When I sent the unit for service, the flow rates were a close to the upper limits, but here at altitude (5000 feet/1525 meters) , they are over the upper limits (except the 60% orifice)

With the 32% orifice being brand new (it came sealed in a small plastic tube from Tecme) I'm at a loss as to why the high flow rates. Does altitude have any effect on flow rates?

I know that in diving the unit, my fiO2 will be higher, and my tank duration will be lower.

Anyone have any insight?

Dsix36 · 21st September 2008, 00:14

I will tell you about my experience, but please verify this before doing it on your own. It worked for me is all that I know for sure.

right after having my 1st stage serviced, the flow rtates were all too high. I took it back and they readjusted the IP pressure. They even showed me, it was exactly 240. When I went home the flows were too high still.

I adjusted the IP pressure to get the correct flow rate. I then checked the flow rates for all the other orifices. They were all exactly centered in the flowmeters. I dove it like this for about 2 years with no issues. I did not have a guage for the IP pressure and can't tell you were it was.

GaryB · 21st September 2008, 02:20

Quote: (Originally Posted by Dsix36)

I will tell you about my experience, but please verify this before doing it on your own. It worked for me is all that I know for sure.

right after having my 1st stage serviced, the flow rtates were all too high. I took it back and they readjusted the IP pressure. They even showed me, it was exactly 240. When I went home the flows were too high still.

I adjusted the IP pressure to get the correct flow rate. I then checked the flow rates for all the other orifices. They were all exactly centered in the flowmeters. I dove it like this for about 2 years with no issues. I did not have a guage for the IP pressure and can't tell you were it was.

Thanks for the info Dsix36!!!

I had that suggested to me by the TDI/SDI IT, whom I took a rebreather refresher from right after purchasing this thing and having it serviced.

I received adapters from Martin at Tecme, and I used that to verify my IP.

I was planning on adjusting the IP to get the flow rates toward the middle of the range today at the shop, but between customers, filling tanks, repairing BC's and a couple of reg's, I ran out of time. I'm hoping to play with that tomorrow.

Thanks again Dsix36!!!

Dsix36 · 21st September 2008, 02:30

Quote: (Originally Posted by GaryB)

Thanks for the info Dsix36!!!

I had that suggested to me by the TDI/SDI IT, whom I took a rebreather refresher from right after purchasing this thing and having it serviced.

I received adapters from Martin at Tecme, and I used that to verify my IP.

I was planning on adjusting the IP to get the flow rates toward the middle of the range today at the shop, but between customers, filling tanks, repairing BC's and a couple of reg's, I ran out of time. I'm hoping to play with that tomorrow.

Thanks again Dsix36!!!

Not a problem at all. Glad that my experience could be of help.

I would be curious to know what you final IP setting is once the flow is correct. I have always wondered how far off mine actually was too.

Don

.

GaryB · 21st September 2008, 02:42

Quote: (Originally Posted by Dsix36)

Not a problem at all. Glad that my experience could be of help.

I would be curious to know what you final IP setting is once the flow is correct. I have always wondered how far off mine actually was too.

Don

.

Don,

I'll definately update this thread with my IP and flow rates.

Cheers!
Gary

si_b_lanzarote · 21st September 2008, 10:42

input pressure varies the flow output remains constant until the ambient violates the 2:1 ratio of in to out pressure.

Bosh · 21st September 2008, 11:46

I see no problem in trying to lower the IP.

Lower the IP to desired flow, and check the IP. If its not much different from 16,3 bar dive it.
Havent done it myself, so i can nor will deside for others how much difference in IP they will accept.

I can tell from experimenting that a 9.4 bar IP gives a 6ish liter flow from a 40% orifice. Flow at 16.5 bar IP is/was within tolerance.

To maintain flow at depth, the IP needs to be 2 times ambient. So an IP of 16 bar will maintain flow down to 70 meters, which is far beyond the intended depth of the Dolphin !

IN THEORY !! an IP of 10 bar is enough to dive to 40 meters, without losing flow at depth. Not that id recommend it.
The firststage is designed to work at an IP of around 16 bar including the ADV and the safetyfeature of the rising IP in case the jet clogs.

Best regards

Bo

gibbogeo · 21st September 2008, 12:43

Quote: (Originally Posted by GaryB)

Does altitude have any effect on flow rates?

No, the pressure downstream (until is less than about 1/2 of the pressure upstream) is not affecting the flow rate.

What influence the flow rate is the upstream pressure (I.P.pressure). Check with a pressure gauge that is not too high.

gibbogeo · 21st September 2008, 12:48

Quote: (Originally Posted by si_b_lanzarote)

i wouldnt have thought the ambient made much of a difference, i was under the impression once input pressure exceeded twice output pressure the cmf would remain constant irrespective of increase to the input to output pressure ratio??

No, the flow is always proportional to the feed (upstream) pressure.

What is ininfluent, for the flow, is the downstream pressure, until remains below about 1/2 of the feed pressure.

Changing the feed pressure (as we do on the kiss to have the right flow) you can increase or diminuish the flow.

si_b_lanzarote · 22nd September 2008, 14:36

Quote: (Originally Posted by gibbogeo)

No, the flow is always proportional to the feed (upstream) pressure.

What is ininfluent, for the flow, is the downstream pressure, until remains below about 1/2 of the feed pressure.

Changing the feed pressure (as we do on the kiss to have the right flow) you can increase or diminuish the flow.

sorry you are absolutely right, it was late!!

i was looking and describing it back to front....the point i was making (rather badly) was lowering or raising the ambient will have little effect until the 2:1 ratio is violated. but of course you can change the ip on the kiss and alter the output flow.

regards si

20th September 2008, 17:46	#1 (permalink)
GaryB New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Feb 2007 Location: Colorado, USA Posts: 54	Dolphin Flow Rates I have a question about the flow rates on the Dolphin.... Here's what I'm seeing for flow rates: 32% orifice - 18.25 LPM <- this is a new orifice from Tecme. 40% orifice - 11.9 LPM 50% orifice - 8.25 LPM 60% orifice - 5.8 LPM The IP is 240 PSI (16.3 bar). When I sent the unit for service, the flow rates were a close to the upper limits, but here at altitude (5000 feet/1525 meters) , they are over the upper limits (except the 60% orifice) With the 32% orifice being brand new (it came sealed in a small plastic tube from Tecme) I'm at a loss as to why the high flow rates. Does altitude have any effect on flow rates? I know that in diving the unit, my fiO2 will be higher, and my tank duration will be lower. Anyone have any insight?
(Offline)

21st September 2008, 00:14	#2 (permalink)
Dsix36 Going Down? Current Rebreather/s: Optima Other Rebreather/s: Join Date: Aug 2007 Location: Deerfield Beach, Florida Posts: 1,135	Re: Dolphin Flow Rates I will tell you about my experience, but please verify this before doing it on your own. It worked for me is all that I know for sure. right after having my 1st stage serviced, the flow rtates were all too high. I took it back and they readjusted the IP pressure. They even showed me, it was exactly 240. When I went home the flows were too high still. I adjusted the IP pressure to get the correct flow rate. I then checked the flow rates for all the other orifices. They were all exactly centered in the flowmeters. I dove it like this for about 2 years with no issues. I did not have a guage for the IP pressure and can't tell you were it was. __________________ THE MORE THAT I LEARN, THE MORE THAT I STILL NEED TO LEARN!!!!!!
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21st September 2008, 02:20	#3 (permalink)
GaryB New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Feb 2007 Location: Colorado, USA Posts: 54	Re: Dolphin Flow Rates Quote: (Originally Posted by Dsix36) I will tell you about my experience, but please verify this before doing it on your own. It worked for me is all that I know for sure. right after having my 1st stage serviced, the flow rtates were all too high. I took it back and they readjusted the IP pressure. They even showed me, it was exactly 240. When I went home the flows were too high still. I adjusted the IP pressure to get the correct flow rate. I then checked the flow rates for all the other orifices. They were all exactly centered in the flowmeters. I dove it like this for about 2 years with no issues. I did not have a guage for the IP pressure and can't tell you were it was. Thanks for the info Dsix36!!! I had that suggested to me by the TDI/SDI IT, whom I took a rebreather refresher from right after purchasing this thing and having it serviced. I received adapters from Martin at Tecme, and I used that to verify my IP. I was planning on adjusting the IP to get the flow rates toward the middle of the range today at the shop, but between customers, filling tanks, repairing BC's and a couple of reg's, I ran out of time. I'm hoping to play with that tomorrow. Thanks again Dsix36!!!
(Offline)

21st September 2008, 02:30	#4 (permalink)
Dsix36 Going Down? Current Rebreather/s: Optima Other Rebreather/s: Join Date: Aug 2007 Location: Deerfield Beach, Florida Posts: 1,135	Re: Dolphin Flow Rates Quote: (Originally Posted by GaryB) Thanks for the info Dsix36!!! I had that suggested to me by the TDI/SDI IT, whom I took a rebreather refresher from right after purchasing this thing and having it serviced. I received adapters from Martin at Tecme, and I used that to verify my IP. I was planning on adjusting the IP to get the flow rates toward the middle of the range today at the shop, but between customers, filling tanks, repairing BC's and a couple of reg's, I ran out of time. I'm hoping to play with that tomorrow. Thanks again Dsix36!!! Not a problem at all. Glad that my experience could be of help. I would be curious to know what you final IP setting is once the flow is correct. I have always wondered how far off mine actually was too. Don . __________________ THE MORE THAT I LEARN, THE MORE THAT I STILL NEED TO LEARN!!!!!!
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21st September 2008, 02:42	#5 (permalink)
GaryB New Member Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Feb 2007 Location: Colorado, USA Posts: 54	Re: Dolphin Flow Rates Quote: (Originally Posted by Dsix36) Not a problem at all. Glad that my experience could be of help. I would be curious to know what you final IP setting is once the flow is correct. I have always wondered how far off mine actually was too. Don . Don, I'll definately update this thread with my IP and flow rates. Cheers! Gary
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21st September 2008, 10:42	#6 (permalink)
si_b_lanzarote Custom Title Allowed! Current Rebreather/s: Inspiration Classic Inspiration Vision Megalodon Ouroboros Other CCR Dolphin Ray Home Build Other Rebreather/s: Other CCR Dolphin Ray Home Build Join Date: Dec 2006 Location: lanzarote, Canary Islands Posts: 103	Re: Dolphin Flow Rates input pressure varies the flow output remains constant until the ambient violates the 2:1 ratio of in to out pressure. __________________ http://www.thediveshoplanzarote.com Last edited by si_b_lanzarote : 22nd September 2008 at 14:55. Reason: ABSOLUTE GIBBERISH! may i be whipped and flogged
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21st September 2008, 11:46	#7 (permalink)
Bosh New Member Current Rebreather/s: Dolphin Other Rebreather/s: Not Bought Yet Dolphin Join Date: Dec 2006 Location: Denmark Posts: 41	Re: Dolphin Flow Rates I see no problem in trying to lower the IP. Lower the IP to desired flow, and check the IP. If its not much different from 16,3 bar dive it. Havent done it myself, so i can nor will deside for others how much difference in IP they will accept. I can tell from experimenting that a 9.4 bar IP gives a 6ish liter flow from a 40% orifice. Flow at 16.5 bar IP is/was within tolerance. To maintain flow at depth, the IP needs to be 2 times ambient. So an IP of 16 bar will maintain flow down to 70 meters, which is far beyond the intended depth of the Dolphin ! IN THEORY !! an IP of 10 bar is enough to dive to 40 meters, without losing flow at depth. Not that id recommend it. The firststage is designed to work at an IP of around 16 bar including the ADV and the safetyfeature of the rising IP in case the jet clogs. Best regards Bo
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21st September 2008, 12:43	#8 (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: Dolphin Flow Rates Quote: (Originally Posted by GaryB) Does altitude have any effect on flow rates? No, the pressure downstream (until is less than about 1/2 of the pressure upstream) is not affecting the flow rate. What influence the flow rate is the upstream pressure (I.P.pressure). Check with a pressure gauge that is not too high.
(Offline)

21st September 2008, 12:48	#9 (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: Dolphin Flow Rates Quote: (Originally Posted by si_b_lanzarote) i wouldnt have thought the ambient made much of a difference, i was under the impression once input pressure exceeded twice output pressure the cmf would remain constant irrespective of increase to the input to output pressure ratio?? No, the flow is always proportional to the feed (upstream) pressure. What is ininfluent, for the flow, is the downstream pressure, until remains below about 1/2 of the feed pressure. Changing the feed pressure (as we do on the kiss to have the right flow) you can increase or diminuish the flow.
(Offline)

22nd September 2008, 14:36	#10 (permalink)
si_b_lanzarote Custom Title Allowed! Current Rebreather/s: Inspiration Classic Inspiration Vision Megalodon Ouroboros Other CCR Dolphin Ray Home Build Other Rebreather/s: Other CCR Dolphin Ray Home Build Join Date: Dec 2006 Location: lanzarote, Canary Islands Posts: 103	Re: Dolphin Flow Rates Quote: (Originally Posted by gibbogeo) No, the flow is always proportional to the feed (upstream) pressure. What is ininfluent, for the flow, is the downstream pressure, until remains below about 1/2 of the feed pressure. Changing the feed pressure (as we do on the kiss to have the right flow) you can increase or diminuish the flow. sorry you are absolutely right, it was late!! i was looking and describing it back to front....the point i was making (rather badly) was lowering or raising the ambient will have little effect until the 2:1 ratio is violated. but of course you can change the ip on the kiss and alter the output flow. regards si __________________ http://www.thediveshoplanzarote.com
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