Single hose or pendulum system
Single hose systems are always pendulum systems. The original oxygen rebreather often had a single hose because this was constructively attractive. The disadvantage of this system is that the gas goes through the scrubber twice. This also has the advantage that the CO2 uptake is better. After all, the gas goes through the scrubber twice. The disadvantage is that the gas becomes much warmer through the same mechanism. Modern lime is so effective that the heating of the gas in a pendulum system in a swimming pool can lead to heat congestion or nausea. In cold water this does not play a role. However, the considerable warming up has contributed to the development of separate inhalation and exhalation systems. Here are some examples of rebreathers with pendulum breathing tubes.
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!