GLAND PACKINGS

To achieve zero leakage between a moving member and a relatively stationery part, a wide range of seals and rings are employed. However, the most common, least expensive and versatile in nature is the Gland Packing. It provides a dynamic seal for a rod, shaft or stem via a housing or gland which is packed with resilient or semi-resilient material, thus providing a localised contact area which offers a physical barrier to leakage

Properties the Gland packing must possess

• Good Anti-Friction Properties

• Good chemical resistance to fluid contained

• Should not get effected by the temperature of application

• Should be reasonably compressible and have a good resilience

• Should retain the self lubricants

• Should not effect the  shaft

• Should not contaminate the fluid being contained

Gland packing is not an exact science as its performance depends upon many variables. The filling of a packing is an art and results depend largely on manual skills. The 'Man with a Wrench' therefore, can sometimes. be a dangerous person in your plant, responsible for scored rods, excessive downtime and wasted packing.

Condition of Plant:

To ensure long and trouble free sealing, check the following periodically:

• The clearance between shaft and neck-bush at the bottom end of the stuffing box. The maximum normal clearance is 0.25mm.

• Concentricity of shaft with stuffing box bore.

• Straightness of shaft (run-out)- not to exceed 0.5mm. Clock gauge reading

• Condition of shaft surface in packing area-no excessive grooves, scores or pitting

• Pump Bearings--wear can induce shaft "whip" which can be harmful to packings.

Packing the GLAND

• Ensure that all the old packing is removed and the stuffing box is clean and free from foreign matter.

• Always re-pack with new packing

• Select correct size of packing to fit the stuffing box dimensions

• Wrap packing on the shaft and cut into rings of correct size

• Fit each packing individually by tamping or with split sleeves

• Stagger joints in consecutive packing rings

• Fit gland follower and check that the shaft rotates freely

• Tighten gland nuts evenly with spanner until the package "drags" when turning the  shaft by hand.

• Valves-pressurise the stuffing box and if necessary re-adjust the gland nuts evenly until a leak-free seal is obtained.

• Pumps-Slacken the gland nuts back and re-tighten to finger tight, to such an extent that the shaft still rotates freely.

                     DETAILS OF PEARL GLAND PACKINGS