| 摘要 |
<p>The non-return valve includes at least one flat, relatively thin circular ring (10) of elastically flexible material such as steel or plastics. The ring rests, in a closed position, against a valve seating with at least one air inflow opening. The seating comprises a surface of rotation concentric with the inlet opening. The outer circumferential edge (14) of the ring is located between two axially spaced annular abutments (15A,16A). These cooperate with the whole outer edge of the ring so that, when the ring is in an open position, its outer edge rests against one of the abutments while the inner edge (12) is displaced slightly so that the ring forms a shallow truncated cone.</p> |
