Blade tip clearance sensor and gas turbine including same

A gas turbine comprising:

• a compressor configured to draw in and compress external air;
• a combustor configured to mix fuel with air compressed in the compressor and to combust a mixture of fuel and the compressed air;
• a turbine in which a turbine blade and a turbine vane are mounted and which is configured such that the turbine blade is rotated by a combustion gas discharged from the combustor;
• and
• a blade tip clearance sensor fixed to a ring segment mounted on an inner circumferential surface of a turbine casing and configured to measure a clearance between a tip of the turbine blade and the ring segment,
• wherein the blade tip clearance sensor comprises:
• a bushing portion fixed to the ring segment and provided with an internal space;
• a washer portion arranged in a lower portion of the internal space of the bushing portion and provided with a first hollow portion;
• a flange portion formed in a circular ring shape having a stepped structure, provided on an upper surface of the washer portion and provided with a second hollow portion corresponding to the first hollow portion;
• a sensor probe inserted into the first hollow portion and the second hollow portion, the sensor probe having a sensor head, a sensor body and a sensor cable;
• a spacer provided on an upper surface of the flange portion and configured to accommodate the sensor probe therein;
• and
• a locking screw provided on an upper surface of the spacer, the locking screw having a thread engaged with and screw-coupled to a thread formed on an upper inner wall of the bushing portion,
• wherein the bushing portion is formed in a cylindrical shape having an internal space, the bushing portion is welded and fixed to the ring segment, and a coupling hole to which the bushing portion is coupled is formed in the ring segment.