CENTERING DEVICE TO REMOVE A SCALE BEING THE INSIDE OF PIPE USING POWERLESS REVOLUTION

A centering device using powerless revolution is provided to prevent a moving body from being upset by conforming the rotation center of the moving body to the center of a pipe line with a spring and a tracking unit installed to the moving body. A centering device using powerless revolution comprises a moving body(4), a first clamp(6), a traction unit(8), a rotary joint(18), a centering unit(16), and a high pressure fluid injection unit(20). A fluid conveying pipe(2) is coupled to the moving body. The first clamp is configured to clamp the fluid conveying pipe to the moving body securely. The traction unit, which is attached to the outer part of the moving body, slides on the inner surface of a pipe line to move the moving body back and forth. The rotary joint is installed to the outer peripheral surface of the moving body, rotated freely by external force. A fluid passing shaft(18a) is installed to the front end portion of the rotary joint. The centering unit, configured to the moving body, positions the rotation center thereof to the center of the pipe line. The high pressure fluid injection unit, coupled to the fluid passing shaft of the rotary joint, injects high pressure fluid to the inside of the pipe line to remove scales. The high pressure fluid injection unit revolves with counterforce generated when high pressure fluid hits the inside of the pipe line. The centering unit includes a second clamp and a spring. The second clamp is coupled to the moving body, separated from the traction unit by a predetermined interval. The spring is disposed between the second clamp and the traction unit in order to compensate for eccentric errors occurred when the moving body passes through a narrow pipe, a wide pipe, and a curved pipe.