What Is a Mechanical Seal?

02 May 2019
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The function of any seal is to provide a barrier to prevent any substance from escaping or entering where two pieces of equipment are joined together. Different seals are suited to different types of applications. In some instances, the function of a seal is to keep moisture out so equipment can be used in wet conditions. In other applications, the seal serves to keep lubrication in place and free of contamination. Seals are vital to industry and agriculture as well as a range of everyday personal technologies such as cars and household appliances. So what exactly is a mechanical seal and how does it differ from other types of seals?

A mechanical seal incorporates a rotating face and a stationary face, as well as a spring to keep the two faces pressed together.  The type of spring varies, it could be a single coil or wave spring or something more complex, but regardless of the spring, it is classed as a mechanical seal. The stationary component is usually held in place with either an O ring or rubber boot, which serves a sealing function and acts as a cushion. The moving piece is typically a shaft.  Sealing is achieved by the interface between the stationary and moving parts.

The right mechanical seal will improve both the productivity and lifespan of the equipment. It will require less maintenance and so involve less down time. It will also minimize wear and tear on the machinery.

What Is a Mechanical Seal’s Advantage over Gland Packing?


Mechanical seals debuted nearly 100 years ago, as technology evolved from steam-driven equipment to electrical power. Before the development of mechanical seals, gland packing was used as a seal in moving parts. Gland packing literally packs the area around the shaft with a rope-like cord of plaited material. It is packed between the shaft and the shaft housing. But as technology developed, the shortcomings of gland packing became apparent. However, gland packing is still used in some applications today. The friction of the moving parts creates heat, which has a negative impact on the gland packing The packing must be lubricated by the media which means pumps using packing are going to drip , If they drip too much they are wasting media, if they don’t drip enough the packing and the shaft could be damaged. Maintaining the correct drip rate requires regular maintenance.

What is a mechanical seal’s main advantage over gland packing? It can be summed up by saying that in most applications, a mechanical seal will need less maintenance, less energy, and eliminate wastage and clean-up costs.. And in manufacturing and agriculture, that means increased profit. For uses such as showers, central heating, swimming pools and spas, mechanical seals provide a reliability that prevents annoying disruptions.

Discover mechanical seals specification sheets here. To request more information regarding mechanical seals, please fill in the product information request form here.
Mechanical Seals