EXPANSION SONDE WITH EXPANSIBLE PACKING

PURPOSE: To simplify a sonde structure, and to improve the sealing accuracy thereof by providing a means which is provided with a sealing element to press an inner surface of a pipe, presses the inner surface, and limits the sliding motion in the axial direction on a separation sleeve from a sonde base part. CONSTITUTION: A sonde comprises a base part 41 having an axial channel 42 to feed the high-pressure fluid and discharge the leaked fluid, a separation sleeve 43, and a sealing device 44. Separation sleeves 43, 45 of different length are fitted at the position of an expanded part to be determined according to the position of a cam 2, and a pair of packings 44 are arranged between the sleeves. The separation sleeve at the end is supported in the axial direction by a shoulder 31 abutted on a fixed stopper 3. When the stopper 6 slides relative to the sonde base part 41, the sleeves 43, 45 are brought close to each other, and the sealing elements 44 are compressed and expanded. The structure is simplified thereby, and the sealing accuracy is improved.