Fluid flow detection device (10) for detecting a fluid flow in a fluid pipe (11) downstream of a check valve (12) being positioned within the fluid pipe (11) when the check valve (12) is closed, wherein the check valve (12) is closed when the pressure differential across the check valve (12) is smaller than an opening threshold, and wherein the check valve (12) is opened when the pressure differential across the check valve (12) is greater than the opening threshold. The fluid flow detection device (10) comprises a first piston (14) being positioned within a first bypass (13), wherein the first piston (14) is designed to become transferred from a first position into a second position when the pressure differential across the check valve (12) is greater than a first threshold that is smaller than the opening threshold, and wherein the first piston (14) closes the first bypass (13) in the first position and the second position； a second piston (16) being positioned within the second bypass (15), wherein the second piston (16) is designed to become transferred from a first position into a second position when the pressure differential across the check valve (12) is greater than a second threshold that is greater than the first threshold but smaller than the opening threshold, and wherein the second piston (16) closes the second bypass (15) in the first position but opens the same in the second position； a first sensor (17) for detecting the position of the first piston (14)； a second sensor (18) for detecting the position of the second piston (16).
