Packing, also known as sealing filler, is usually woven from relatively soft linear materials with a cross-sectional area of square, rectangular, or circular strips that are filled into the sealing chamber to achieve sealing. The earliest form of packing seal was to use fibers such as cotton and linen to plug the leakage channel to prevent liquid flow leakage, mainly used as shaft seals for water lifting machinery. Due to the wide range of filler sources, easy processing, low price, reliable sealing, and simple operation, it has been used to this day. Nowadays, packing is widely used for shaft seals of centrifugal pumps, compressors, vacuum pumps, mixers, and ship propellers, reciprocating shaft seals of piston pumps, reciprocating compressors, refrigeration machines, and rotary seals of various valve stems.
