Abstract: A device for measuring a clearance between tips of blades of a ring of blades and an interior wall of a casing surrounding the ring of blades in a turbomachine includes a probe which is mounted radially on the casing. The probe has an end made of a material that can be abraded by the tips of blades as they rotate. The device also includes a printed circuit arranged in a mid-plane of the probe. The probe contains an axis of rotation of the ring of blades. Further, the printed circuit includes a number of adjacent U-shaped electrical circuits that have bases arranged in a probe end likely to be abraded by the tips of blades. The bases lie at different depths from a reference level defining the interior wall of casing. The printed circuit also includes a recognizer for determining which U-shaped electrical circuits have been broken by abrasion and which U-shaped electrical circuits are intact.

Abstract: The invention concerns a play measuring sensor by multiple depth abrasion comprising a probe (7) capable of being mounted on a housing (5) enclosing a gas turbine engine blade rim (2), made of a material capable of being abraded by the tops (3) of the blades (2). The probe (7) comprises a printed circuit having a plurality of U-shaped electric systems whereof the bases (22a to 22e) are arranged in the end of the probe (7) facing the blades (2) and located at different depths (3a to 3e) relative to a reference level defining the inner wall (4) of the housing (5). The sensor is connected to means identifying the intact circuits and the electric circuits cut by abrasion.