The size and Number of Packing Ring

The number of packing rings may vary depending on the objective of the sealing system or the requirements of the rotating equipment. The most common packing arrangement for rotating equipment is illustrated in figure. Three rings of packing are used to seal the process liquid from the packing lubricant. Two rings between the lantern and gland are used to restrict the leakage of the lubricant to the atmosphere. The size of packing depends on the size of equipment, typically for rotating shafts, the standard square size packings shown in the table may be considered.

For packing to operate properly the finish on the shaft sleeve must be at least 16 μin (0.4 μm) conterline average (CLA) and the finish in the bore should be 63 μin (1.65 μm) CLA. The sleeve must be harder that the packing and chemically resistant to the liquid being sealed. If the sleeve has a coated material for a hard wear surface, the sleeve must also have good thermal shock resistance.

Fibers	Metal
Mineral	Animal	Vegetable	Synthetic	Lead
Metal Graphite	Wool Hair Leather	Flax Ramie Jute Cotton Paper	Nylon Rayon TFE Carbon Aramid Polyamide	Copper Brass P-Broze