常見例句Keywords vacuum reaction stove;vacuum degree;master pump;forepump;smelting;modification; 真空感應爐;真空度;主泵;前級泵;熔鍊;改造;mechanical forepump 機械預抽真空泵forepumpn. 預抽真空泵(前級泵)vacuum forepump 前置真空泵 返回 forepumping