Page 79 - Valve Selection Handbook

66 Valve Selection Handbook

used for this purpose are compression packings based on compressed
asbestos or PTFE and O-ring packings.
In the case of the piston valve shown in Figure 3-20, the piston moves
in two packings that are separated by a lantern ring. The lower packing

Figure 3-20. Piston Valve, Standard
Pattern, Seat Packing Mounted in Valve
Body, Piston Pressure Unbalanced.
(Courtesy of Rich. Klinger AG.)

Figure 3-21. Piston Valve, Standard
Pattern, Seat Packing Mounted in Valve
Body, Piston Pressure Balanced.
(Courtesy of Rich. Klinger AG.)