Before steam admission , valve on vacuum hogging extraction line ( the valve is befor hogging pipe of the two stage steam jet ejector ) should be closed ( see also two stages steam jet ejector installation and operation instruction ) 在蒸汽進入之前,抽真空啟動管道上的閥門(啟動抽汽器前的閥門)應該關閉(請參見相應的兩級射汽抽氣器安裝使用說明書) 。