A device having a flow channel (K) for a fluid has a nonreturn valve (4) arranged in the flow channel (K), said nonreturn valve (4) allowing the fluid to flow through the flow channel (K) in a first direction and preventing it from flowing through the flow channel (K) in a direction counter to the first direction. The device furthermore has a flow detector (5) for detecting the flow of the fluid through the flow channel (K) , wherein the flow detector ( 5) detects a change in the nonreturn valve (4) . This detected change serves as an indicator for the flow of the fluid. The device according to the invention enables flow detection with simple means, in that a nonreturn valve that is present is used as an indicator means.
