短語詞組短語Back PRSSure Valve 單向閥BWV back water valve 回水閥shuttle back pressure valve 梭式止回閥Back pressure valve [機]背壓閥;止回閥;回壓閥;逆止閥downhole back flow valve 井下回流閥arrow back pressure valve 供應(yīng)箭形止回閥back wash valve 反沖洗閥back fire valve 回火閥門back flow valve 回流防止閥 返回 back valve