Oxygen partial pressure management and control loop design of a closed circuit rebreather

Nowadays, the number of divers who want to practice the activity at technical level grows more and more. The Rebreather apparatus can be used to carry out such an experience. This underwater breathing equipment seems to be a complex system, but it is based on a very simple concept: the reuse of the exhaled gas. This apparatus is controlled by an electronic system, a specialized dive computer, that monitors all vital parameters and makes life easier for the diver. This paper presents the control techniques used to manage the oxygen level into the breathing loop, studying all the factors that contribute to its changes during the dive.