| 摘要 |
<p>An air valve that comprises a concave, downwardly facing cover (4) which is carried by a pipe connector (1) connected generally coaxially thereto, wherein the upper edge-part of the pipe connector (1) is surrounded by the wall of the cover (4), a ring-shaped, upwardly facing first seat ridge (8) which is carried by and sealingly connected to the cover wall (5), a second ring-shaped seat ring (2) which is generally coaxial with the cover wall (5) and is carried by and sealingly connected to the upper end-part of the pipe connector (1), and a valve plate (11) which is vertically movable in the cover (4) and which carries an annular, rubber-elastic valve washer (20) that can rest sealingly on the first and the second seat ridges (8, 2) so as to bridge an annular air through-gap between the seat ridges. Both main surfaces of the valve washer (20) have a surface roughness which is adapted to substantially avoid strain in the outer layers of said main surfaces. <IMAGE></p> |
