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Piston rod pressure packing | Packing rings - Sealing rings
The general term “packing rings” also englobes sealing rings, pressure-breaking rings, backup rings and oil wiper rings. These are all "floating" parts in that they are free to move laterally in their housings at the same time as the piston rod, while at the same time providing a seal.
The packing rings are the main components of the packing case as they provide a seal along the full length of the piston rod. They are designed to automatically compensate for wear. There are two main types: segmental packing rings and labyringth rings (“double and triple circle” packing rings).
Segmental packing rings are the most commonly used of the two. Each ring is made up of three to six parts with radial or tangent cuts, held together by an external garter spring.
The basic sealing component comprises a pair of rings: one with straight cuts and one with tangent cuts which are pinned together with the cuts offset by a third each time, thus preventing direct leakage along the piston rod.
CASTANET offers a wide variety of rings to meet the different service conditions.
Double or triple circle packing rings provide an extremely efficient labyringth type seal. Their design is radically different from that of segmental packing rings. The cross-sections are much smaller, requiring less space, but more parts are needed.
They are particularly recommended for high-pressure service and non lubricated applications.
