1, automatic exhaust gas valve
This is an active valve device that discharges helium while isolating seawater. This device automatically opens the valve by using the difference between the inside and outside of the case, thereby discharging the helium in the watch. Most dive watches use this device, the most well-known such as the Breitling Avengers second-generation deep diving sea wolf watch, this professional diving watch is water resistant to 10,000 feet (3,000 meters). The watch features a one-way ratcheting bezel, a screw-in anti-slip crown and a safety relief valve that balances the pressure difference inside and outside the case. However, the automatic drain valve requires regular maintenance because of the possibility of water leakage due to aging of the aborted valve apron.
2, manual exhaust gas valve
The manual exhaust gas valve needs to be unscrewed when in use, similar to a screw-in crown, and needs to be re-locked after use. The valve of this type of diving watch in the normal state is sealed by the inner upper rubber ring, which is not available when the valve is locked. Loosen the valve and the unit is under reduced pressure. When the pressure inside the watch is sufficiently greater than the pressure outside the watch, the rubber ring under the valve inside will be retracted to release the gas. Once the pressure equalizes, the lower rubber ring will be pushed back to the original position by the spring, and the action will be repeated many times during the decompression process. Some brands have introduced a coaxial diving watch with a manual helium trap at the 4 o'clock position to manually discharge helium during decompression. Equipped with 8500 coaxial movement, waterproof 1200 meters. At the beginning of the hippocampus series design, manual helium exhaust valves were also used.