| 摘要 |
<p>Backflow preventer has a housing (11) which has a inlet opening (15), outlet opening (16) and at least one leakage opening disposed between the inlet opening and outlet opening in flow direction (18). The valve housing (42) has two separated annular grooves (48,49) arranged outside in flow direction. The seal rings (51,52) are arranged in each annular groove.</p> |
