Chuck for use in investigating strength properties of plasti tube under pressure testing

The utility model relates to a checking instrument, particularly a cramping apparatus without the axial outer force during detection. The utility model is characterized in that the cramping apparatus is provided with a tube base, and the inside of the tube base is provided with a sealing base and a nut. The inside of the seal base is provided with a sealing ring, and the nut is fixed with the sealing base. The purpose of the utility model is to solve the existing questions that the detected cramping apparatus can not be provided with pipe joints like three-way elbows, etc., detected components with different wall thickness, and detected components with half hard materials; the installed time is long, the cramping apparatus is bulky, and the cramping apparatus after test is inconvenient to disassemble.