Packed plug for a fluid valve

Abstract

In a valve structure, a valve plug apparatus to provide a leak-tight valve shut-off, is disclosed. The valve structure includes a valve body provided with an inlet passage, an outlet passage and an internal web portion intermediate the inlet and outlet passages. A closeable passage-forming means is arranged in the web portion and a two-member valve plug is mounted on a valve stem for controlled axial movement within the web portion and operable to close said closeable fluid passage-forming means to shut the valve. In accordance with the invention, the two-member valve plug comprises a lower plug member and an upper plug member which are in a generally axially spaced relation on the valve stem. Packing means is held in a snug-fitting condition between the lower and upper plug members by an axially resilient member which acts between one end of the valve stem and the valve plug to urge the lower and upper plug members together. When the two-member valve plug closes the closeable fluid passage-forming means, a force is transmitted by the valve stem directly through the upper plug member to the packing means to form a leak-tight seal for the valve plug. The stem force is also transmitted through the packing means and lower plug member to generate a seating force between the valve plug and closeable fluid passage-forming for a tight valve shut-off.