| 摘要 |
A sewer pipe with double automatic backflow preventer, having the following features: - an installed rubber bladder 30, which is connected to a compressed-air source 34 via a valve 33, shuts off the throughflow cross section in the inflated state, and once air has been evacuated from it at least largely releases the throughflow cross section as a result of its shape; - a sensing element 35 is installed and sets the valve 33, during normal throughflow, to air evacuation and, during backflow, to feeding compressed air into the bladder 30; - the rubber bladder 30 is assigned a second automatic shut-off element to protect against backflow. In order to achieve essentially the same overall length as in the case of a sewer pipe with a single backflow preventer, this sewer pipe also has the following features: - the sewer pipe has a cleaning opening, known per se, in a box-like top housing part 13, which is closed off by a cover 15; - the bladder 30 and the sensing element 35 are installed in the cover 15; - the bladder 30 is in the form of a flat plate and a sensing element 35 is an electric level controller, the electrodes 36 of which are arranged a little way above the top of the outflow connector 12; - the inflow opening can be closed by a flap 20 which is retained by spring force approximately horizontally beneath the bladder 30 within the top housing part 13 and which can be pivoted into its closed position from the outside by a wedge 18 on a vertically guided rod 17. <IMAGE> |
