| 摘要 |
<p>The backflow preventer has a closing body led into a casing (2) and able to be pushed against the flow (Pf1) onto a valve seat with a seal (40). The seal has an outer fixing edge (6) round it, which is fitted and stressed inside an annular groove (10) between casing parts (7,8) which can be brought together axially. The uncompressed cross-section of the annular groove is greater than the cross-section of the seal fixing edge within it. This edge has a sealing projection (15) extending radially outwards round it. The OD of this projection in the undeformed state is greater than the internal radius of the annular groove.</p> |
