| 摘要 |
<p>The invention relates to a nonreturn valve (1 ) intended to be used inside a tube structure (3), the area of flow (2) of said nonreturn valve (1 ) can vary by aid of a movably provided flap (4) located in the tube structure (3), which minimizes, closes or prevents a return flow (5) of fluid (6), which is fed as a flow forwards (7) in said tube structure (3), said tube structure (3) consists of e.g. a tube, a discharge pipe, a tube in process industry, the oil industry or the chemical industry. The flow forwards (7) and the return flow (5) take place mainly in a horizontal direction, and said flap (4) is movably provided in at least one place in its upper part (21 ) in the tube structure (3) at the same time as it by its own weight is suspending downwards, when no flow forwards (7) exists, and said flap (4), which is mainly stiff, comprises a first limiting surface (8) having at least one bulging portion (10) turned towards said return flow (5), when said return flow (5) is stronger than said flow forwards (7) or when said return valve (1 ) is closed, then the opposite second limiting surface (9) of said flap (4) being turned towards the flow forwards (7), but in the case said flow forwards (7) is stronger than said return flow (5) the flap (4) is pressed aside by the flow forwards (7) in providing an enlargement of area of flow (2) and an opening of said nonreturn valve (1 ).</p> |
