Patent attributes
A backflow preventer (1) is provided that, in an insertable housing (2) thereof, includes a valve member (6) located in a housing interior (5). The valve member (6) sealingly rests against a valve seat (7) in the closed position thereof while being movable from the closed position thereof into the open position thereof counter to a restoring force. The interior (5) of the housing is provided with an interior section (A) which has an interior cross section that is larger than the outer circumference of the valve member in the movement zone of the valve member (6). In order to prevent undesired noise from developing as a result of the valve member (6) vibrating on the inner circumference of the housing when the quantity of flow medium is low, the invention provides an elastic valve member guide (9) at least in a movement zone of the backflow preventer (1) near the valve seat (7), that is effective between the valve member (6) and the interior housing wall surrounding the interior section (A) to guide the valve member (6) in a play free manner.
