Mechanical seals and gland packing material has been used for shaft sealing and several other applications over a period of time. However, in order to obtain best results, the material for gland packing has to be carefully selected and must possess certain properties.
Features of Good Gland Packing
In order to have full proof packing with no leakage, following are the properties needed to be possessed by the material used for gland packing:
- No chemical reaction: The gland packing should not react with the liquid that is to be sealed as otherwise it will collapse leading to leakage of the liquid.
- Anti-friction feature: The stationary beside the side of stuffing box and the shaft rubs against the gland packing. If friction occurs then the gland packing will cut the shaft sleeve or the shaft and may also burn because of being overheated consistently.
- Resistance to temperature: Gland packing should be resistant to the fluid’s working temperature at any cost.
- Resilience and compressibility: When the gland flange belts out the force, the gland packing should compress and fortify the shaft and again revert to its original shape on the release of the tension.
- Lubricant retention: Several lubricants such as grease, graphite, petroleum products are used to coat the gland packing prior to its insertion. This lubrication needs to remain on the gland packing to maintain its anti-friction properties.
- No contamination with the fluid: In sensitive industries like pharmaceutical and the food industry, the gland packing should not contaminate the fluid that is being sealed.
- Non-corrosive: The gland packing should not get corroded so as to prevent damage to the shaft.
Where is Gland Packing Used?
Gland packing is used in the following applications:
- Sealing of static items like manholes, tank hatch etc
- Reduction of leakage along the stem of varied valves like the gate valve, globe valve and ball valves.
- Reduction of leakage of the fluid in question in reciprocating pumps
- Reduction of leakage of the fluid in question in centrifugal pumps, gear and screw pumps
- Sealing of propeller shafts in life boats and merchant ships belonging to the older generation
The type of gland packing material used for each of the above differs because of the varied nature of the applications. The choice of the material is determined by the pressure, temperature, corrosiveness etc of the fluid that is to be sealed.
Just as gland packing material prevents leakage of fluids, pipe with puddle flange is used when water penetration has to be prevented along the exterior surface of pipes passing through concrete structures. Gland packing is made of varied materials and a combination of one or more; sometimes metal wires may be used to give added strength. Some of the basic materials used are flax, jute, cotton, hemp, wrapped metal foils, carbon fibre, graphite fibre, glass fibre, PTEE. Aramid, poly acryl nitrile fibres etc.
Sourcing
Reputed manufacturers of gland packing material, pipe with puddle flange, stainless steel plates are listed on online directories. It is always better to go for top quality items which are available from these dealers. Thus, sourcing of items of varied nature has been made very easy in today’s times.