Expanded Use Of Split Seal Technology For Large Pumps And Agitators

By Scott Boyson, A. W. Chesterton Corporation

New advances in split mechanical seals have expanded its application for use in both water and wastewater systems. These systems move vast amounts of fluid through pipes and tanks. Water-based fluid systems comprise the largest fluid transport systems in the world with wastewater streams being the largest. While the systems' designs can vary by region, most use centrifugal pumps to move fluid. Many of the centrifugal pumps are very large and difficult to assemble, so they have not typically been sealed by mechanical seals which require total equipment disassembly. However, split mechanical seals have advanced so that these pumps can now be sealed without equipment disassembly.

Compression Packing
Compression packing is commonly used to seal the shaft of large equipment. Tightening the packing gland compresses the packing axially and the packing expands radially. A static seal is created between the stuffing box wall and packing. A dynamic seal is created between the rotating shaft and the packing inside diameter. The dynamic interface between the packing and shaft generates frictional heat and wear. Packing requires the pumped fluid to leak to minimize the impact of the frictional heat. This leakage provides the necessary longterm lubrication to the packing set and will carry heat away to minimize heat buildup.