Data Sheet

Sliding-Stem Live-Loaded Packing
Product Bulletin
59.1:061
July 2009
2
smooth stem surface and live-loading, give you long
service life with very low maintenance. The
live-loading provides a constant load over the life of
the packing material. This greatly reduces or, in
many applications, helps to eliminate your need for
packing box adjustment and maintenance. The
installed packing system provides excellent sealing,
guiding, and transmission of loading force.
D Easy Installation in Existing Valves—All
parts needed to install the systems in existing valves
are available in a convenient kit.
D Adaptable to Many Applications—
ENVIRO-SEAL systems are available with PTFE,
Graphite ULF, or Duplex packing for 9.5 through
31.8 mm (3/8 through 1-1/4 inch) diameter valve
stems on CL125 through CL600 valves. HIGH-SEAL
systems with Graphite ULF packing are available for
9.5 through 50.8 mm (3/8 through 2-inch) diameter
valve stems on CL600 through CL2500 valves.
Standard ENVIRO-SEAL PTFE packing systems can
be used in vacuum service with packing rings in the
standard orientation. It is not necessary to reverse
the PTFE packing rings.
Lubrication Recommendations for
ENVIRO-SEAL Packing Systems
Do not lubricate ENVIRO-SEAL packing
components or the bonnet bore prior to
assembly. Lubrication is often used as part of
standard valve assembly techniques. However,
lubrication is not required for the ENVIRO-SEAL
packing systems.
Lubrication is required for the packing studs and
nuts. While it is important to properly lubricate the
stud threads and internal nut threads, it is also
important to properly lubricate the contacting face of
the nut.
ENVIRO-SEAL Duplex Packing
Systems
ENVIRO-SEAL Duplex packing systems (figure 2)
are available for Fisher sliding-stem valves with
valve stem diameters ranging from 9.5 to 31.8 mm
(3/8 to 1-1/4 inches). See table 2 for a list of
applicable product types and stem diameters.
ENVIRO-SEAL Duplex packing systems were
developed, utilizing the benefits of both PTFE and
graphite components. These special packing
systems provide the capability of graphite packing
along with low friction advantages of PTFE packing.
Thus, ENVIRO-SEAL Duplex packing systems
provide a low friction, low emission, fire-tested
solution for applications with process temperatures
below 232_C (450_F). ENVIRO-SEAL Duplex
packing systems were tested in accordance with API
Standard 589, “Fire Test Evaluation of Valve Stem
Packing”, first edition.