[مكساج]

اقتباس:  المشاركة الأصلية كتبت بواسطة chengzi86     The Universal Air Valve (not gate valve) is designed to permit the automatic escape of large quantities of air from a pipeline when the line is being filled, and to permit air to enter the pipeline when the line is being emptied.

Dear ... I grateful for your response...but I did not understand what you want to say, could you please explain what you whant to say ?
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