How to Change Mechanical Packing to a Split Cartridge Mechanical Seal

Braided packing has long been the solution for large paper pulp transfer equipment due to its low upfront cost and ability to be installed and removed without complete equipment disassembly. Braided packing does come with its downfalls, however:

  • Requires permanent high-flow flush to lubricate packing.
  • Can result in permanent damage to the shaft or shaft sleeve, thus requiring equipment disassembly and replacement of components.
  • Ongoing adjustments to the packing follower are necessary to decrease leakage as packing wears.
  • Frequent maintenance and adjustments result in decreased equipment availability and increased labor hours.

While braided packing can be a solution for many services, its upkeep requirements often force operators and maintenance personnel to consider the option of mechanical seals. When considering the broad range of mechanical seal styles and products to replace braided packing, the most readily implemented, effective, and reliable is a split cartridge mechanical seal with a ViseSeal O-Ring Vise (ORV), O-ring mounted bearing/bushing system.

How to Easily Install a Style 85 Split Cartridge Mechanical Seal

The Flexaseal Style 85 fully split cartridge mechanical seal coupled with an API 682 Plan 32 external flush and a fully-split ViseSeal O-Ring Vise (ORV), O-ring mounted bearing,​ is an excellent option in a wide variety of services such as the common light slurry applications seen in paper pulp equipment.

Diagram of API 682 Mechanical Seal Piping Plan 32

A split ViseSeal ORV and Style 85 seal allow for a rapid conversion in the field as well as simple and efficient service after installation. The Flexaseal Style 85 split cartridge mechanical seal is a true two-piece installation, with minimal handling of parts and a quick install. The mechanic simply removes the existing packing and packing gland, reconditions the seal chamber sealing surfaces, and then mounts the split mechanical seal system without having to disassemble the equipment. Large equipment (e.g. split case pumps) that may have been a timely and costly endeavor to disassemble can now service the mechanical seal without handling the casing or rotating elements.

The ViseSeal ORV not only dramatically decreases flush water consumption with its tight radial clearance over the shaft, but it also provides extra radial shaft support in a non-galling and self-lubricating composite material for added longevity. A ViseSeal ORV reduces flush water entering the process stream to a small fraction of the original flow rate as compared to mechanical packing. Eliminating radial shaft movement greatly increases seal life and improves performance and because mechanical seals limit the rotating contact area to the seal faces only, the large amounts of shaft or sleeve wear from packing contact are eliminated.

The Style 85 split cartridge mechanical seal is designed to be installed outside the seal chamber and away from any packing-worn sleeve surfaces, meaning that pump sleeve replacement (and equipment teardown) is only necessary in the most severe cases. Flexaseal can also provide the appropriate split adapter plate to house the ViseSeal ORV and permit the mounting of our standard seal to your specific equipment.

With paper pulp services that can plug flush lines or impact normal seal operation, the use of an API 682 Plan 32 will act to isolate the seal and allow it to run on clean, cool liquid for maximum seal longevity. Any existing water supply infrastructure used to cool and lubricate braided packing may also be used for the Plan 32 implementation, but users must confirm that the water supply pressure is at least 15 psi greater than the expected seal chamber pressure.

Reduce Water Consumption With a Style 85 Split Cartridge Mechanical Seal

The split sealing system described here has provided long-term cost savings and improved mean time between failure for many end-users. By working with Flexaseal’s engineering team to identify the right setup, customers can be certain they’ll realize major savings in energy & water consumption, reduce maintenance requirements, and increase equipment productivity.

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