Mechanical Seals
Mechanical seals play a crucial role in maintaining the performance and efficiency of various industrial machinery, ensuring leak-free operations in demanding conditions. Serving as dynamic seals, these finely engineered components create a barrier between the moving and stationary parts of a machine, effectively containing fluids and preventing leaks.
With their intricate design and precise construction, mechanical seals provide robust sealing solutions that can withstand high pressures, extreme temperatures, and aggressive media. By effectively sealing the rotating shafts of pumps, compressors, and other equipment, mechanical seals prevent contamination, reduce energy consumption, and enhance overall system reliability.
Their ability to endure challenging operational environments makes mechanical seals indispensable in industries such as oil and gas, chemical processing, power generation, and wastewater treatment. With ongoing advancements in material science and sealing technology, hydraulic and pneumatic seal specialists continually strive to develop innovative mechanical seals that meet the evolving needs and demands of modern industries.
The most basic design of a mechanical seal will have 7 key components, as shown in the image to the left.
1 • Stationary component.
2 • Sealing member for stationary component
3 • Rotating component.
4 • Sealing member for rotating component
5 • This is the spring.
6 • This is the gland plate.
7 • This is the clamp ring.
There are four main sealing points on this kind of mechanical seal, these are highlighted by the orange rings (see image above). The first sealing point, also known as the primary seal, is between the stationary component (1) and the rotating component (3). The second sealing point, or the secondary seal, is between the rotating shaft and the sealing member. This may be as shown in the image, an o-ring, a v-ring or other sealing rings. The third sealing point is between the stationary component (1) and the gasket (2). The fourth sealing point is between the gland wall and the stationary component (1) this will be done using a gasket or o-ring.
The most important sealing point of the mechanical seal is the primary seal. This is where the stationary component and the rotating component are pressed against each other by the force of the spring behind the rotating component. The two faces that are pressed against each other will be lapped (precision machined to be extremely flat). The flatness of the faces can be measured in light bands, which is a unit of measurement found using an optical device over the top of the faces. The flatness of both of these faces against each other minimises any leakage to the point of it being practically insignificant. Any leakage that does occur at this sealing point will actually appear as vapour.
Like most other seals an oil, lubricant or other type of fluid will be present. For mechanical seals the fluid present will be used to create a fluid film in the primary seal, between the stationary component and the rotating component. Without the fluid film present the two faces against each other will wear, heat up and degrade rapidly.