Mechanical seals in chemical industry

 

The main functions of seals are to contain pressure, maintain vacuums, and control unwanted particles from collecting in machinery.

The majority of mechanical seals for the chemical industry are planned to operate with aggressive fluids, dangerous and pollutant liquids, but also in the operation of extreme temperature conditions that these liquids can reach during processing

 

Classification:-

1)Dynamic Contacting Seals

    Dynamic contacting seals are used with sliding surfaces.

 

Types:-

• Radial lip seals are made of elastomer and made to form to their surroundings

• Mechanical face seals consist of a set of simpler seals, that seal against each other

• Dual-mechanical seals are made of two sets of seal faces with a barrier of incompressible fluid located in the space between them

• Packing seals use different materials, such as graphite and cotton, to form a seal between surfaces.

 

USES

•Radial lip seals are used primarily to exclude contaminants from equipment with rotating shafts.

•Mechanical face seals were originally used in the automotive industry for engine coolants, but now is also used in chemical industry

•Packing seals are used in many applications, depending on the type of packing used. One very typical use of packing seals is to provide a seal for reciprocating and rotating shafts, such as in valves and pumps.

 

 

2)Dynamic Non-Contacting Seals

Non-contacting seals have a small gap between the seal and the shaft that minimizes wear. Non-contacting seals have a small gap between the seal and the shaft that minimizes wear.

 

Types:-

•Labyrinth seals are used with high-speed rotation shafts when a small amount of leakage is acceptable.

•Bushing is a ring of metal or composite inserted in a plate or other type of equipment to relieve the wear on a shaft or other piece of machinery.

•In hydrodynamic seals the shaft acts as a pump.

 

 

USES

•Labyrinth seals are typically used in centrifugal compressors, such as the one shown here, and steam turbines.

•Bushings seals are used to protect the lubrication for other seals from contacting abrasive fluids, they can be found in conveyor rollers.

•Hydrodynamic seals are used in applications requiring rotating shafts such as oilfield drilling and production tools.