针形阀位置提前，便于接近。
检测组件上的所有针形阀都必须关闭。
在该系统中，针形阀i常闭，针形阀常开。
In this system, I often close the needle valve, needle valve is always open.
在开始检测前，检测组件上的所有针形阀都必须关闭。
Before starting test, all needle valves on test kit must be closed.
开启排气针形阀，并从软管排放空气。然后关闭排气阀。
Open vent needle valve and bleed air from hose. Then close vent valve.
完全开启排气针形阀直到从排气连接处的滴漏停止为止。
Open vent needle valve fully until dripping from vent connection stops.
开启针形阀“B”排放空气，然后关闭“B”和排气针形阀。
Open needle valve "b" to bleed air and then close "b" and vent needle valve.
开启针形阀“B”排放空气，然后关闭“B”和排气针形阀。
Open needle valve "b" to bleed air and then close "b" and vent needle valve.
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