| 摘要 |
PURPOSE:To eliminate the room for stagnation or adhesion of hyperfine dust particles by boring plural pieces of holes to the wall of a stainless steel pipe, bulging the peripheries thereof to the outside and attaching adapters of the same diameter by butt welding to the holes, then finishing the inside surfaces by electrolytic polishing. CONSTITUTION:Plural pieces of the holes 21 of a prescribed diameter are bored to the wall of the stainless steel pipe 20 having a prescribed diameter and the peripheries of the holes 21 are bulged by the conventional method to form bulging parts 22. The front end faces of said parts are finished smooth. The adapters of the same diameter are attached by butt welding to the upper part of the bulging parts 22 to form branch pipes. The penetration beads of weld zones 24 are smoothed by polishing. Such pipe is then immersed in an electrolyte and the entire inside surface is finished by the electrolytic polishing, by which a manihold 25 as a product is produced. The weld zones are decreased and the unpolished parts of the inside surface are eliminated by this constitution. This manihold is, therefore, adequate as an apparatus for supplying high-purity gases in a process for producing semiconductors. |
