Abstract: Self-contained underwater re-breathing apparatus having a breathing circuit, an injection system for adding fresh breathable gas to the breathing circuit, and an automatic control system including a microcomputer for monitoring physical parameters in the breathing circuit and controlling the feeding of breathable gas to the breathing circuit in accordance with said physical parameters. The re-breathing apparatus has a bailout system automatically activated in an emergency, where the breathing circuit is shut off, and the diver starts inhaling directly from the breathable gas supply and exaling to the environment. With the system of the invention, a part of the existing closed circuit is used for bailout, and no separate bailout circuit is provided. Therefore, there is no need to incorporate in the mouthpiece means for switching from one breathing circuit to another, and the mouthpiece can be kept smaller and simpler.

Abstract: Self-contained underwater re-breathing apparatus having a breathing circuit, an injection system for adding fresh breathable gas to the breathing circuit, and an automatic control system including a microcomputer for monitoring physical parameters in the breathing circuit and controlling the feeding of breathable gas to the breathing circuit in accordance with said physical parameters. The re-breathing apparatus has a bailout system automatically activated in an emergency, where the breathing circuit is shut off, and the diver starts inhaling directly from the breathable gas supply and exaling to the environment.