Dräger SMS1B semiclosed-rebreather

Hose dependent Mixgas Swimmdive unit with bypass

This rebreather is equipped with a 1 litre backup cylinder filled with 200 bar.o Brother unit SMS1 has another way the diver is supplied with gas. The SMS1 is a tethered system where the pressure is regulated in the diving bubble. With the SMS1/B, a gas with a pressure of 40 bar is fed to the diver through the umbilical. In the rebreather, the pressure is reduced to ambient pressure. As a result, the diver will have a significantly better WOB because the breathing gas pressure is constantly adjusted to the ambient pressure.

DATASHEET SEMI CLOSED REBREATHER
SMS I/B	Date: 09 November 2005
Schlauchabhängiges-Mischgas-Schwimmtauchgerat mit Bypass (Hose dependant – Mixgas – Swim diveunit with Bypass)	Database semi closed rebreathers by: J.W. Bech
Manufacturer	Dräger	(name or company)
Designer		(name)
Model	SMS1/B	(number type)
Land of origin	Germany	(country)
Design year	1969-1970	(actual project start)
Special Note:	Variant See SMS 1	(additional space for info)
User group	Military	(sport/mil/civil/fire)
Magnetic characteristics		(if known)
Part no:	T12 170	(part #)
Working principle	Constant Mass Flow	(CMF/Metering,Passive)
Gas type	Heliox 17,5/82,5	(Heliox/Nitrox)
Gas mix type	% Oxygen	% Helium	Flow	Worktime	Depth
(backup) Heliox	17,5	82,5		8 min	200m
1 liter backup cylinder filled with 200 bar.o The CMF will work to max 40 bar, therefore 160 liter gas is available. Since 8 min dive time is referred to the flow will be 20 ltr/min. Presuming the diver is @ 200 meter and using his emergency bailout with a metabolic use of 1,5 liter of oxygen per minute the half closed quotation gives a FiO2 of (20l/minx0,175)-1,5 / 20l/min – 1,5 = 0,108 % resulting of a 2,27 bar pO2 at depth.
Intended use	From dive bell or UW lab.	Sport/MC/Deep/Tethered
Dimensions LxWxH	500x420x160 mm	(outside in mm)
Device weight	(12 kilo empty) 14 kilo filled	(filled+gas on land)
Intermediate Pressure		(IP )
Overpressure valve	11 cm – 17 cm WK adjustable	Range
Max depth	200	(mtrs)
Used material for housing/backplate	glasfibre
Pressure reducer	Membrane type	Membrane / Mushroom
Connection reducer – bottles	M22 x 1,5
Supply pressure	200 bar, minimum 30 bar
Umbilical connection	Yes
Manual bypass	Yes
pO2 measurement standard	No
Pressure gauge range
Cylinders	1 litre
Cylinder material	Steel
Cylinder thread	M22 x 1,5
Valve	–
Designed for gas  mix	17,5 / 82,5 heliox
Co2 absorption cartridge capacity	2,5 liters	(early square form!)
Co2 absorption cartridge rechargeable	Yes by the diver
Co2 absorption cartridge storage time	–	(month/year)
Co2 absorption time testing (CE)	Not CE
Connections Co2 cartridge	screw
Guaranteed absorption time	3 hours
Grade of absorption material	Drägersorb
Breathing bag material	Reinforced rubber
Inhale bag volume	5,5 liters
Exhale bag volume	Total = 5,5
Total loop Volume	Total volume ~8,5 liters
Operating temperature	–
Magnetic signature	–
Colour (s)	Yellow
Worn	On the back
FFM attached	NO	(mask)
Mouthpiece valve	Yes
Extra info:
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!
The Big difference between the Dräger SMS 1 and the Dräger SMS 1/B are two aspects. Biggest difference is the SMS 1 is supplied with ambient gas. The pressure is reduced in the diving bell where the MVB unit is located. The SMS 1/B on the other hand has a medium pressure supply of 40 bars and the pressure reduction is performed in the rebreather. Also the SMS 1/B is equipped with a manual bypass on the bottom of the glass fibre housing. Gas supply is realised by using the MVM unit.
Important features:   Gas supply via umbilical, 40 bar medium pressure to diver, gassupply located in diving bellMixed gas prepared in diving bell by means of the unit MVM @ 40 barBuild in bailout system consisting of: Pressure reducer – CMF valve – Mix gas bottle of 1 liter\Low breathing resistance due to large diameter hosesScrubber with low resistance for W.O.B and water lockAll parts are build in the housing made of glass fibre, worn on the backSeparated inhale and exhale counterlung, resulting in a cleaner scrubber bed.Low resistance in the water due to compact form and small measurements of the unit.Easy maintenance by replaceable parts

This rare rebreather was designed back in the early 1970s and was used for deep-sea operations offshore and for military purposes. As documentation is narrowly available a call to anyone who has information to add to this document to send it to me. I can then add it and keep it for the readers of my website!

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