Recently I obtained a new rebreather for my collection. This German Dräger Oxy D 30 M is a half hour self rescue rebreather built in 1986.
The rebreather is delivered in a stainless steel container with a band-lock. The rebreather is designed for 30 minutes and has a constant mass flow system combined with a lung demand oxygen system. In this small container Dräger fitted a full face mask, an oxygen bottle, a refillable scrubber and even a oxygen flow timer system! The unit is designed to be used in extreme conditions.The lock has a orange piece of plastic that break away when the unit is opened. This shows the unit need serviceWhen the upper part of the unit is taken off the counterlung and the ffm pops out. On the mask a small cord is attached. This cord activates the oxygen timer. The timing device, which is activated by pulling the plug while donning the mask. It is programmed to give a sound, so you’ll no it is working. After a preset time, approx. 30 minutes, it give a beeping sound, assuming oxygen supply to be near it’s end, so that rescuers may trace the user, provided he is still in a danger zone, and endangered by the end of oxygen supply. (this information thanks to Matthias! )When we look in the lower part of the container we see a bourdon gauge is mounted and the valve of the oxygen cylinder. The container is supplied with a window showing if the bottle is filled with oxygen.The valve ha a spring lock system preventing the valve is accidently closedWhen the oxygen bottle is taken from the unit we can clearly see the CMF nozzle that supplies the oxygen to the loopThe container has a strong carrying strapHere we see the oxygen bottle connected to the scrubber (gray) and the counterlung. The rubber part is the housing for the cmf and demand valveThe scrubber and the bottle are both supplied with a nitriel O-ring to mount properly in the stainless housingWhen we dismantle the rubber part we see the yellow breathing tube that return the cleaned breathing gas to the maskThe upper part of the counterlung is equipped with a sealed oxygen timer. There is a red LED that clearly shows the timer is working. Unfortunately this timer was completely sealed so I could not see how it worked… Fortunately Matthias informed me about the mechanism. The timing device, which is activated by pulling the plug while donning the mask. It is programmed to give a sound, so you’ll no it is working. After a preset time, approx. 30 minutes, it give a beeping sound, assuming oxygen supply to be near it’s end, so that rescuers may trace the user, provided he is still in a danger zone, and endangered by the end of oxygen supply. (this information thanks to Matthias! )Here you see the breating tube from the mask to the sensor and down to the scrubber. You might think how the gasflow is organised. Well the next picture shows this smart design ideaUnderneath the sensor three mushroom valves are fitted. Also a central valve is fitted so the gasflow is forced in one direction!Here we see the valves that take care of the flow directionInside of the foldable FFMThis shows how the timer is activated. When activated the pin pulls out and activate the timer circuit.This timer is attached direct above the valvesHere you can clearly see the complete configuration.The counterlungThe oxygen valve has a one way direction. This is achived by the locking system. The user can however close the valveThis is done by lifting the ring and turning anti-clockwiseHere you see the lung operated oxygen supply. The unit delivers 1,8 ltrs of oxygen constant, but when more oxygen is needed the counterlung will shrink and activate this microvalve. It is highly sensitive and a superb designThe bourdon gauge in more detailA key to open the scrubber is supplied with the unit.The scrubber is a double walled designStainless meshfiltersThe container has approximately 0,7 ltr of draegersorb
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!
