| 摘要 |
<p>A non-return valve unit for insertion into a substantially horizontal waste water pipe comprises a horizontal tubular portion (10), and a flange (11) surrounding one end of the tubular portion and angled obliquely to the vertical such that the outer face of the flange, relative to the tubular portion, is directed upwardly. The flange mounts on the upper part of the outer face thereof a pivot (12) carrying a closure member (13) engageable with the outer face to close the tubular portion.</p> |
