| 摘要 |
A ball valve includes a valve housing 10 and a ball 20. A pair of mirror-symmetrical housing halves 12, 14 are jointed together along a single weld line to enclose the ball having a through bore and a pair of recessed portions. The through bore 22 is in conformity with the weld line. Holes 42, 50 for respectively mounting a pair of stem assemblies are formed in portions of the valve housing opposed respectively to opposite ends of the through bore. The through bore of the ball is brought into alignment with openings 12A, 14A of the valve housing, and the recessed portions 26, 28 of the ball are brought into alignment with the holes, respectively. Next, the pair of stem portions 60, 68 are attached to both holes and fitted into both recessed portions, and the stems are welded circumferentially to peripheral edge portions of the holes, respectively. |
