| 摘要 |
The invention relates to a device for preventing backflow (1), comprising a housing (2) provided with an inlet and an outlet forming a flow path leading from the inlet to the outlet; two return valves (9, 10, 23, 30) which open out into the direction of flow and which are arranged behind each other; a discharge channel (16) which discharges from the intermediate area between the two return valves; a valve body (17) which seals the discharge channel (16) inside the housing and which is sealingly displaceable in relation thereto inside the housing, said valve body being displaced by the effect of a spring in order to occupy an open position in which the discharge channel is released and occupying a closed position when the housing is cross-flown counter to the effect of the spring, receiving therein the return valve, which is arranged downstream. The aim of the invention is to enable a device provided with said device for preventing backflow to be additionally operated in a suction mode, wherein a blocking device (34) which maintains the two return valves (9, 10, 23, 30) in an open position and which maintains the valve body (17) in a closed position is provided. |
