Gaskets are materials used to seal one compartment of a device ...

XXVIII. ASBESTOS PACKINGS
A. Product Description
The term packings is generally assigned to the subset of packings that are
designated~asdynamic (static packings are gaskets). These dynamic or
mechanical packings are used to seal fluids in devices where motion is
necessary. Examples where these packings have traditionally been used are in
pumps, valves, compressors, mixers, and hydraulic (piston-type) cylinders
(Kirk-Othmer 1981). Within the mechanical packing segment there are various
types of packings (e.g., compression, automatic, and floating packings), but
only compression packings are or have been made using asbestos fibers (FSA
1983).
Asbestos-containing compression packings can be formed into various shapes
for different uses as illustrated in Figure 1. The simplest form of
compression packings (hence forward packings) is of the loose bulk type. Bulk
formulations consist of blends of loose fibers and dry lubricants that are
bound with a liquid or wax binder. These simple packings have only limited
applications (e.g., packings for injection guns) and are not considered in the
remainder of this report. Fiber mixtures are more often extruded with a
binder and lubricant and used as a core in packings that have a braided yarn
jacket that imparts greater durability to the packing (Kirk-Othmer 1981).
The braided variety of packings are the most prevalent and all of the
well-known packing manufacturers produce them by similar methods of
construction. Asbestos packings are braided of strong, highest quality pure
asbestos yarn. In addition, they may be constructed using an Inconel(R) or
other wire insert around a resilient asbestos core
impregnated with graphite.
They are lubricated throughout and surfaced with anti-frictional dry lubricant
graphite (EPRI 1982). The simplest form of braided packing is the square
braided variety that utilizes asbestos yarns of the six grades defined
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