| 摘要 |
<p>The intake mouth has an intake inlet (8) for a flow of water towards an outlet (3) connected to a pump. Shutter means (12) are switchable from a resting position, in which the outlet (3) communicates with vent means (13-16), into an operating position, when the flow of water is caused to move towards the outlet (3), wherein the shutter means (12) shut said vent means (16). The shutter means (12) are adapted to switch from said operating condition into the resting position when said flow of water descends below a pre-determined threshold value, so as to enable air to penetrate the intake mouth to unprime said pump. <IMAGE></p> |
