Abstract: A hardening apparatus comprises a tracing gauge that is a member having the same axis shape as the axis shape of a bent pipe and being held in an attitude identical to the bent pipe, and a tracing device that is a member which can move in the longitudinal direction of the bent pipe and the tracing gauge and can move in the direction perpendicular to the longitudinal direction. A guide part engaged with the tracing gauge in a manner slidable along the tracing gauge is held at one end of the tracing device, and a hardening device is held at the other end. A transportation device moves the hardening device in the longitudinal direction by moving the tracing device.

Abstract: In a flexible pipe having upstream side and downstream side inner tubes disposed internally of a bellows tube, the interference of the bellows tube with the inner tubes is prevented and the inner opening ends of both the inner tubes are disposed in the very close proximity to each other to prevent the impingement of a fluid on the bellows tube. For this purpose, the flexible pipe includes a bellows tube 1 having bellows portions 1e, 1f on the both sides thereof with each of the bellows portions composed of ridges 1c and valleys 1d and a straight tube portion 1g formed at the center of the bellows tube 1 in the longitudinal direction and having a diameter expanded to substantially the same diameter as that of the ridges 1c. The, the inner opening end 2d of one of inner tubes 2 and the inner opening end 3e of the other of the inner tubes 3 are disposed within a range of the straight tube portion 1g of the bellows tube 1 and face each other in close proximity to each other.