同心异径管concentric reducerﻫ偏心异径管eccentricreducer 锻制异径管reducingswage 螺纹支管台threadoletﻫ焊接支管台weldolet 承插支管台sockolet 弯头支管台elbolet 斜接支管台latroletﻫ镶入式支管嘴sweepolet 短管支管台nipolet 支管台,插入式支管台boss