What is Active Addition for Semi-Closed Circuit Rebreathers?
The active addition system is a key component of SCRs, controlling the feed gas’s addition to the breathing loop. The mechanism adds a specific quantity of gas regardless of the current loop volume, providing a constant supply of breathable gas while preventing hyperoxic or hypoxic conditions. At its core, the active addition system consists of a supply valve controlled by the diver or an electronic mechanism. When the diver inhales, the decrease in loop volume triggers the valve to release more gas into the loop. In electronically controlled systems, gas is added at fixed intervals, ensuring a continuous supply.
What is Open Circuit Scuba?
Open circuit scuba diving is a method of underwater diving in which the diver breathes from a tank of compressed gas and exhales directly into the water. This system is contrasted with closed-circuit systems, where exhaled gas is recycled and re-breathed. Open circuit scuba is the most common and widely used system in both recreational and professional diving. It is valued for its simplicity, reliability, and the extensive training programs available to certify divers. The ease of use and availability of open circuit scuba equipment have made it a cornerstone of underwater exploration.
What is Closed Circuit Scuba?
Closed circuit scuba, commonly referred to as rebreather technology, represents a significant advancement in underwater breathing apparatuses. Unlike traditional open circuit scuba systems, which release exhaled gases into the water, closed circuit rebreathers recycle the diver’s exhaled breath. This recycling process involves scrubbing carbon dioxide from the exhaled air and adding the necessary amount of oxygen to make the gas breathable again. Closed circuit systems are renowned for their efficiency in gas usage, allowing divers to stay underwater for extended periods. These systems are particularly favored in scientific research, military operations, and technical diving, where extended bottom times and reduced gas consumption are crucial.