| 摘要 |
An air admittance valve configured when subjected to a negative pressure condition to vent a pipe system to an ambient environment. In general, the air admittance valve includes a main body, inner and outer valve seats, a flexible sealing element, and a lid. The inner and outer valve seats define at least one vent opening between valve seats that is configured, when open, to communicate with the ambient environment. The flexible sealing element is devoid of a rigidifying structure, is configured to move to and from a closed position and an open position, and defines an outer perimeter surface, an inner perimeter surface, and opposite top and bottom surfaces extending between the outer and inner perimeter surfaces. At least one of the lid or the main body further comprises one or more guiding elements that define one or more guiding surfaces configured to guide the sealing element to and from the closed position and the open position. |
