Dräger Atlantis and Dolphin semiclosed-rebreather

Dräger 90’s sportsrebreather semiclosed

In the mid-1990s, Dräger launched the Atlantis 1 semi-enclosed rebreather. Shortly afterwards, the model became the Dolphin rebreather. The rebreather was widely sold by a huge number of dealers which increased to a substantial market share a few years later. These two rebreathers certainly contributed to the success of the rebreather in the sports diving world in the Benelux. The simple design was later also widely used to be modified into closed MCCR systems. See the homebuilder section of my website for this.

Therebreathersite was founded by Jan Willem Bech in 1999. After a diving career of many years, he decided to start technical diving in 1999. He immediately noticed that at that time there was almost no website that contained the history of closed breathing systems. The start for the website led to a huge collection that offered about 1,300 pages of information until 2019. In 2019, a fresh start was made with the website now freely available online for everyone. Therebreathersite is a source of information for divers, researchers, technicians and students. I hope you enjoy browsing the content!

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DATASHEET SEMICLOSED REBREATHER
Atlantis 1	Date: 21 June 2006 Updated 2022
Predecessor of the Dolphin	Database semi closed rebreathers by: J.W. Bech
Manufacturer	Dräger	(name or company)
Designer		(name)
Model	Atlantis I	(number type)
Land of origin	Germany	(country)
Design year	1994	(actual project start)
Special Note:	Predecessor of Dolphin	(additional space for info)
User group	sportsdiving	(sport/mil/civil/fire)
Magnetic characteristics	n.a.	(if known)
Part no:		(part #)
Working principle	Constant Mass Flow	(CMF/Metering,Passive)
Gas type	Nitrox	(Heliox/Nitrox)
Gasmix type	% Oxygen	% Helium	Flow	Worktime	Depth
Pure Oxygen (no color)	100	0	1,4-2.0 barL/min	470* (180)	4
Nitrox60 (black)	60	0	5,8 barL/min	121	17
Nitrox50 (red)	50	0	7,3 barL/min	96	22
Nitrox40 (blue)	40	0	10,4 barL/min	67	30
Nitrox32 (yellow)	32	0	15,6 barL/min	45	40

Intended use	Sport	Sport/MC/Deep/Tethered
Dimensions LxWxH	340x435xdepth190 mm	(outside in mm)
Device weight	17 kg	(filled+gas on land)
Intermediate Pressure	40 bar	(IP )
Overpressure valve	18-25 mbar	Range
Max depth	40	(mtrs)
Used material for housing/backplate	ABS
Pressure reducer	Membrane type	Membrane / Mushroom
Connection reducer – bottles	M24x2 EN144-2
Supply pressure	200 bar, minimum 20 bar
Umbilical connection	No
Manual bypass	No
pO2 measurement standard	No
Pressure gauge range	0-250 bar
Cylinders	4 or 5 litre
Cylinder material	Steel
Cylinder thread	G ?
Valve	M24x2
Designed for gasmix	Nitrox
Co2 absorption cartridge capacity	2,3 liter
Co2 absorption cartridge rechargeable	Yes
Co2 absorption cartridge storagetemp	-20ºC to 50 ºC
Co2 absorption time testing (CE)	Yes
Connections Co2 cartridge	P-connectors
Guaranteed absorption time	2,5 hours
Grade of absorption material	Drägersorb
Breathing bag material
Inhale bag volume	7,1 ltr (inhale+exhale)
Exhale bag volume
Total loop Volume	Total volume 10,5 liter
Operating temperature	15ºC to 25 ºC	When used in temperatures below 10ºC the scrubber material should be stored at room temperature during 12 hours and the scrubber filled direct before the dive!
Magnetic signature	n.a.
Colour (s)	Blue/White
Worn	On the back
FFM attached	NO	(mask)
Mouthpiece valve	Yes
Extra info:	160 N	Positive wing buoyancy
Additional information:
Email address owner:
URL owner:
If you have any information to add this sheet please mail it to jw.bech@quicknet.nl References to source and names will always be added!
Info found:
Origin: http://www.therebreathersite.nl
Info:

The Atlantis (and early types of the Dolphin) were delivered with a doses measuring device. Duration for dosage testing where: 60% oxygen content, lower limit 184 seconds upper limit 250 seconds. 50% oxygen content, lower limit 147 seconds upper limit 196 seconds. 40% oxygen content, lower limit 97 seconds upper limit 135 seconds. 32% oxygen content, lower limit 72 seconds upper limit 90 seconds.

Measuring the gasflow using the standard measuring device For this test, take the volume flow test device (41) or another suitable volume flow measuring device and connect it to the quick coupling (48) with the bypass valve. A mixing gas cylinder containing the relevant mixture for the volume flow to be tested with at least 50 bar filling pressure must be connected to the reducing valve. The test device must lie on a horizontal surface and move freely during the test. Breathe through the housing of the safety valve (49) to completely empty the test device and then monitor it for approx. 20 s. No leakage should occur and the bag of the test device should remain folded together. Then fill the housing of the safety valve up to the fill mark (43) with water. You should hold the housing upright in your hand during the entire measurement. Now open the mixing gas bottle and start the time measurement at the same time. Measure the time until the first gas bubbles emerge from the water-filled reducing valve. The measured times should be within the values listed in Table 6.1.1.


Mengsel Onderste grenswaarde Bovenste grenswaarde 60% O2/40% N2 184 s 250 s 50% O2/50% N2 147 s 196 s 40% O2/60% N2 97 s 135 s 32% O2/68% N2 72 s 90 s
Checking the volume flow with the Dwyer ball flowmeter The Dolphin rebreather can also be supplied with the compact Dwyer MMA Series Mini Master ball flow meter. Two types of flowmeters are available from Dräger. With the first type, the scale runs from 0-25 litres/minute and with the second type, a coloured area indicates the range within which the output of a particular nozzle should lie. Both types are universal flow meters (i.e. not specifically made for the Dolphin) and are therefore suitable for measurements at both pressure and vacuum. As a rule, these flow meters are therefore supplied unassembled so that the user can assemble the meter himself for his specific application. To do this responsibly, the supplier (Dwyer) has enclosed clear assembly instructions for this purpose. For our specific application, we recommend building up the flow meter for working with overpressure with a control valve in the lower connection.This control valve allows the gas supply to increase in a controlled manner until the maximum volume flow is reached. This prevents the so-called “dancing” of the ball that occurs when the flow meter is suddenly pressurised. When measuring, ensure that the flow meter is held in perpendicular position and the control valve is fully open while reading the volume flow.

Failure to adhere to this warning may result in serious injury and death. If the measured values are outside the specified ranges you should check whether you have made a mistake and perform the measurement again accurately in accordance with the operating instructions. If the value is then still outside the specified range then take the device to an authorised professional. After the volume flow test has been completed, close the mixing gas cylinder and wait until the pressure in the middle and high pressure range is zero (no pressure indication on the manometer). After closing the mixing gas cylinder, the indication on the manometer should decrease evenly. If this is not the case, the pressure gauge must be checked by a specialist. Pour the water out of the safety valve housing and disconnect the connection between the test device and the bypass valve. If you want to test the regulators with a suitable float meter (suitable for mixed gas), the volume flows must be in the following ranges (table 6.1.2): Mix vol-% O2 / vol-% N2 Lower value (L / min) Higher Value (L / min) 60/40 5,1 6,4 50/50 6,55 7,95 40/60 9,4 11,3 32/68 14,2 16,9 Photos and text thanks to Tino de Rijk and Rita Oosterbaan IANTD instructors Netherlands.