| 摘要 |
In accordance with the present invention, there is provided a control valve comprising a valve body having a valve bonnet which is cooperatively engaged thereto. The body and the bonnet collectively define a housing which accommodates a valve trim comprising a flow control element and a complementary valve plug. The plug is attached to a reciprocally rotatable valve stem of the control valve. In the control valve, the reciprocal rotary movement of the valve stem of the valve through the packing area thereof, rather than the reciprocal liner movement of the valve stem through such packing area, is used to facilitate the reciprocal linear movement of the plug cooperatively engaged to the stem. The use of a rotary stem design instead of a liner reciprocating stem is operative to reduce fugitive emissions from the valve. |
