Our range of air vents work on a simple, yet effective and efficient principle. Under normal working conditions the SIR release mechanism remains closed. Where there is built up air within the water supply, the float within the body of the valve lowers as the air collects. When the volume of air collected reaches a predetermined level the float causes a linkage to the release mechanism to be under tension and opens the valve to the atmosphere. The water level rises as the air is released; causing the float to rise, the linkage to relax and the valve closes. Operation of the discal deaerator; consisting of a brass body with integral interrupter fins, the discal deaerator works to remove all air particles as water flows through the unit. Automatic air vents- the range of automatic air vents is operated via a float mechanism and is designed for the removal of air from systems.