This bulletin provides information and insight to help
you select Fisher packing systems properly. The
following application guidelines have been developed
to aid in the packing selection process. It is important
to note that these guidelines were developed based on
the results of numerous tests on various packing
systems conducted in the Emerson laboratory.
Exceeding these guidelines might result in reduced
service life.
ENVIRO-SEAL™ packing systems provide an improved stem seal to help prevent the loss of process fluid.The stainless steel materials, specialized seals, and extension bonnet are designed to meet cryogenic temperature requirements.The metal-to-metal seat is designed and manufactured to provide long-lasting, reliable, tight shutoff at both ambient and cryogenic temperatures, without the need for periodic lapping.Rugged cage guiding for the ET-C and EWT-C provides high valve plug stability, which reduces vibration and mechanical noise.ET-C and EWT-C balanced valve plugs permit the use of smaller, lower-cost Fisher actuators.Low flow requirements can be satisfied with standard restricted-capacity trim or with Micro-Form, Micro-Flute, or Micro-Flow valve plugs.Extensive cryogenic testing during the development of the valve design reduces the need for expensive cold testing for most applications, which results in quicker delivery and greater value.