| 摘要 |
<p>The device (1) has a hollow head (2) presenting a seat (11), and aspiration pipes (5a, 5b) projecting into the head. The seat delimits a space, and a swing type valve (4) is housed in the space. The valve is cooperated with the seat for adopting closing positions in which the valve closes the pipes during functioning of the device. A prefilter (9) e.g. fine mesh screen, is placed in the head for avoiding blocking of the valve through debris e.g., leaves, in the space.</p> |
