Safety non-return device for the bottom of a pond

摘要

The device (1) has a flexible element (4) comprising a closing portion (22). The closing portion covers communicating openings (14) to hermetically close the communicating openings in a sealed-off configuration, and is moved away from the openings by thrust force of liquid from ground to a basin in a pass-through configuration. The closing portion and an annular shutter forming part are located on a same wall under which filling flow of the liquid can pass from the openings to a level of a free edge of an annular shutter (24) when the flexible element is in the pass-through configuration.