Air and Vacuum Valve
The Cla-Val Series 35 Air and Vacuum Valve is designed to perform two separate functions. First, it will allow large quantities of air to be exhausted from the pipeline as it is being filled with water. When this air has been vented completely, water will enter the valve causing the float to seal tightly against the seat to prevent water flow. Second, if the line is being drained, either intentionally or as a result of pipeline breakage, the valve responds to the loss in pressure and opens. This allows air to re-enter the pipeline and prevents a potentially damaging vacuum from developing.
Series 35 Air and Vacuum Valves should be installed at high points or at grade changes within the pipeline. Mount the unit in the vertical on top of the pipeline with isolation valve below each valve in the event servicing is required. A vault with adequate venting and drainage should also be provided.