Products  : Packings : Gland Packings

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

Properties The Gland Packing Must Possess

• Good anti-friction properties

• Good chemical resistance to fluid contained

• Should not get affected by the temperature of application

• Should be reasonably compressible and have a good resilience

• Should retain the lubricants

• Should not affect the shaft

• Should not contaminate the fluid being contained

Hindustan composites manufactures a wide range of Gland packings to suit a variety of applications. They are of both Dry as well as Lubricated types.

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

Hindustan composites takes great care at the construction stage of its gland packings which lead to a better performance even under minor imperfections in the plant condition and fitment. However certain preparatory precautions, correct procedure of fitment, selection of grade and size of the gland packings would help in achieving the best results.

Condition Of  Plant

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

• Concentricity of shaft with stuffing box bore.

• Straightness of shaft (run-out)-not to exceed 0.05 mm. 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.

• Choose packings recommended for the fluid to be contained.

• 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 tapping 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 packing "drags" when turning the shaft by hand.

• A) Valves - pressurize the stuffing box and if necessary readjust the gland nuts evenly until a leak-free seal is obtained.

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

Running - In

(This does not apply to valves) After starting the pump, allow it to run with a steady leakage for the first 15 minutes. Then begin to adjust the gland-nuts equally, one or two flats at a time, about 10 minutes between adjustments, until the leakage is reduced to an acceptable level. If during the procedure the gland begins to overheat, slacken off the gland nuts slightly to increase the leakage rate, thus reducing gland temperature. Commence re-tightening again after a further 5 - 10 minutes.

N.B.: Some leakage from the gland should always be maintained (approx. 10 drops/min.) to ensure adequate lubrication and cool running the packing.

When gland leakage is not permissible or when handling fluids contain abrasive substance in suspension, it is a normal practice to introduce a "fluid or liquid seal". This is achieved by feeding more acceptable fluid into the stuffing box by the use of a lantern ring. Regular maintenance should ensure that the lantern ring is correctly positioned and that the lubricant feed pipe is clear of obstruction.

To facilitate the selection of suitable grade of gland packings, certain guidelines are given in this catalogue under the heading 'Medium for Selections'. In the case of specific applications, the Technical Cell of Hindustan Composites is always available for customer guidance.

The following recommendations are general for the selection of suitable dimension: