difference between mechanical seal and gland packing

The difference between mechanical seal and gland packing

Describe difference between mechanical seal and gland packing – Seal and packing are integral and essential elements in a pump system, shaft, and several other mechanical engineering applications. Mechanical seals and gland packing are the top-rated and most-preferred sealing mechanisms.

There are differences between features and work mechanism, though. Hence, the selection has to be made with care.

Incorrect selection may lead to higher maintenance costs and lower operational efficiency. The article gives a quick comparison between the two.

Mechanical Seal

The mechanical seal is popular in diverse applications. It is almost maintenance free, and leakage problems rarely happen in this case. Thus, operations run smoothly and uninterruptedly month after month.

The mechanical seal is durable and sturdy. However, the life of seal depends on the work environment, type of liquid, ambiance temperature and duration of the operation.

Mechanical seals use water or other compatible liquid for lubrication. The seal faces are lubricated using a boundary layer of liquid or gas. Either the pumped liquid provides lubrication, or it is provided externally; depending on the application.

Due to constant pressure and high temperature, wear and tear happens in mechanical seals. Especially, the dry run should be avoided as it may damage the seal completely.

Two flat primary sealing faces that are perpendicular to the shaft minimize the leakage. Typically, one soft and one hard material are used so that there is minimal adhesion between the two faces.

Carbon-graphite is the preferred material for the soft surface whereas silicon-carbide or ceramic is the preferred choices for a hard surface.

In some cases, both surfaces are hard, e.g., while handling abrasive liquids.

Low consumption of energy makes it ideal for round-the-clock applications.

One static seal and secondary static seals are used in mechanical seals. Single spring or multiple springs (or metal elbows also used sometimes) maintain face contact.

Gland rings, collars, compression rings, and pins are the other hardware components.

Gland Packing

Gland packing is a conventional shaft seal which is preferred by mechanical engineers.

In certain applications, gland packing is preferred over mechanical seals, e.g., dealing with aggressive fluids.

If there is any leakage, then it can be adjusted while the pump is in service. In the other scenario (when mechanical seal is used), it is not possible.

The gland packing is not suitable for every situation. For example, it is not an ideal solution for applications where abrasive liquids are used.

In Gland Packing, rope-like braided material is packed around the shaft. Thus, the gap between the pump and shaft gets filled with the packing material. The packing also requires frequent adjustment and lubrication.

Leakage increases with use because the packing wears away gradually which needs to be repacked. Also, the groove needs replacement time and again.

To keep the gland packing cool; a constant flow of water is required. As the packing material generates friction against the shaft, more drive power is needed to turn the shaft. It causes wastage of energy.

Both gland packing and mechanical seals are effective and useful. It depends on economic viability, personal preference and requirement specification; which one will be preferred. Here you know the difference between mechanical seal and gland packing.

Leak-Pack specialize in providing solutions to all types of leakages by manufacturing Mechanical Seals and Sealing Components as per customer’s drawings, samples or requirements. To know more about Mechanical Seal call on +91-(2739) 271592 or email at info@leakpack.com.

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