| 摘要 |
PURPOSE:To produce a bend having a uniform diameter by forming the bend of plural tubular bodies of which the joint parts are made into the elliptical shape inclining to the pipe axis, joining the joint parts to a circular shape and rounding the angles, then exerting a fluid pressure in the bend. CONSTITUTION:Straight pipes are cut alternately at the equal positive and negative angles of inclination relative with the pipe axis. The joint parts 3 of such plural tubular bodies 1 having the same shape are joined to each other to form the entire pipe part A into a bend. Reinforcing rings 2 are mounted by means of holders 5 via clearances 4 to the intermediate parts of the respective bodies and lock rings 8 are mounted on the inside and outside near the end face 3' of the elliptical shape thereof. The face 3' is made circular by using tightening means 9. The joint parts 3 are welded from the inside and angle parts 7 are shaped away to make the wall thickness in weld zones 6 equal to the wall thickness of the bodies 1. The rings 8 are removed and a fluid pressure is exerted in the bend to deform the part near the center of the bodies 1 toward the outside to eliminate the clearances 4. The circular mitre bend having the smooth joint parts 3 is thus obtd. |
