| 摘要 |
<p>The present invention provides an air admittance valve (1), suitable for connection to a pipe (8) to admit air thereto, comprising a hollow valve body (2) adapted to form a substantially tight seal with the pipe (8), and a valve element (3), which is hollow and of substantially conical shape having an open wider end sealingly retained to the valve body (2) and a narrower end which is imperforate except for a slit (19). At least the narrower end is resilient. Under normal and increased pressure conditions in the pipe (8) to which the valve (1) is connected for use the slit (19) is closed and under reduced pressure in the pipe (8) there is a flexure of the narrower end which causes the slit (19) to be opened, allowing air to pass into the pipe (8). The slit (19) forms a seal with a reduced tendency to stick or leak, in comparison to conventional air admittance valves. <IMAGE></p> |
