Detection unit for a rotating measuring ball, as well as flowmeter

A detection unit (5) for detecting passages of a measuring ball (23) rotating in a measuring chamber (17) of a flow unit (3), the detection unit comprised of a housing (27) containing detection means (29) and a planar printed circuit board (31) carrying electronic components (33), wherein the housing (27) comprises a C-shaped housing part (35) having an inward-facing inner wall (35A), an outward-facing outer wall (35B), and two end walls (35C) which at ends of the housing part connect the inner wall and outer wall together, where a distance (39, 45) between the inner wall (35A) and a line of symmetry (37) of the housing part initially increases from one of the ends (35D) onward and then decreases, and where the printed circuit board (31) is C-shaped and between the inner and outer walls a component space (41) is situated in which the printed circuit board is present, which printed circuit board is provided with an inside edge (31A) and an outside edge (31B), where the inside edge (31A) is present at a distance (43) from the inner wall (35A) of the housing part, which distance has such a value that when the detection unit (5) is snapped on the flow unit (3) the inner wall (35A) of the C-shaped housing part (35) does not come into contact with the inside edge (31A) of the printed circuit board (31).