Back flow prevention device for drinking water line has 2 successive non-return valves displaced within housing of device for controlling leakage opening and preventing pressure rise at outlet opening

摘要

The device has a housing (12) provided with at least one leakage opening (23) between an inlet opening (18) and an outlet opening (19) and 2 successive non-return valves (54,74), the first of which is displaced relative to the housing for controlling the flow connection between the inner space between the non-return valves and the leakage opening. The second non-return valve is supported so that it can slide relative to the housing without impairing the sliding movement of the first non-return valve.