First, what is Conventional Compression Packings?
Below are some examples.
Braided packing of cotton fiber, impregnated with PTFE. The low friction coefficient of the surface layer of the PTFE allows the use in condition of relatively high peripheral speeds.
Constructed with aramid fiber; each strand is individually treated with a PTFE coating and a light, inert oil. This product is a great performer in extremely abrasive environments.
As seen from above, compression packing has two components:
Carrier Fibers have to handle the forces acting on the packing when it is compressed by the gland as well as the forces from the operating pressure of the fluid it is sealing.
Blocking agents and Additives are materials used to fill the voids when the carrier fibres are braided into packing. They are also added during manufacturing to adjust the properties needed by the packing.
There are many types of carrier fibers that can be used. Plant fibres like cotton or jute, flax, etc. Animal fibre like wool and mineral fibres like asbestos and graphite. Synthetics fibres are carbon, Teflon, rayon, glass, aramid and Kevlar. Metallic fibres such as foils made of aluminium or stainless steel are also used for high-pressure high-temperature services.
There are many types of blocking agents and additives that can be added during the manufacturing of conventional packings. Teflon and graphite powder dispersions; silicone-based lubricant; high-temperature lubricants; mineral or vegetable oil; graphite lubricants can be coated to the packing to adjust the final properties of the packing. These processing additives can be added via coating or impregnation processes.
Conventional Shaft Packings
Many different types of carrier fibers in combinations with various types of added additives to make different types of shaft compression packings.
Conventional Packings are made of Carrier Fiber plus added Additives.
All conventional packings are made with added additives.
Second, what happened to the additives during operations?
It can be concluded that Conventional Packings with Added Additives will limit the life span of the packing once the additives are lost during operations. How long the MTBR of your equipment is now determined by the conventional packing you used!
Contact us for more details about how SLADE Patented Packings and Gaskets has extended the MTBR by as much as six times of conventional packings.