What Are Oil Seals? Oil Seal Applications & Uses

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What Are Oil Seals?

Oil seals, also known as rotary shaft seals, are a type of gasket used to prevent lubricant leakage and contamination in rotating machinery by creating a barrier between the moving and stationary parts.


These seals are designed to fit snugly around the shaft of the machine, preventing oil from leaking out while also keeping dirt, dust, and other contaminants from entering.

What is an oil seal and how does it work?

Rubber gaskets, commonly used in various industrial applications, serve the purpose of preventing oil leakage and maintaining the integrity of machinery by creating a barrier between two or more components.


Oil seals, also known as rotary shaft seals or lip seals, are a specific type of gasket designed to prevent the leakage of oil or other fluids in rotating shafts. 


They are typically made from elastomers such as rubber or silicone and consist of an outer metal case with a sealing lip on the inner side.

Rubber Gasket

Sealing process

The sealing process involves the interaction between the rotating shaft and the elastomeric material, resulting in a dynamic barrier that prevents fluid leakage and maintains system integrity.


Seals are designed to create a tight seal around the shaft by utilising a combination of lip geometry, surface tension, and lubrication. When the shaft rotates, the lip of the oil seal comes into contact with the shaft surface, creating a frictional force that generates heat. This heat helps to soften and conform the elastomeric material of the oil seal to the shape of the shaft, ensuring an effective sealing action.


Additionally, lubricants can be used on both sides of the oil seal to reduce friction and enhance sealing performance. The sealing process is crucial for preventing contaminants from entering machinery or equipment while keeping essential fluids contained within.

Types of oil seals

Different types of rotary shaft seals are available in the market, including radial lip, axial lip, and mechanical face seals.


  • Radial lip seals are the most common type of oil seal used to prevent leakage of fluids such as oil or grease in rotating machinery. They consist of a metal outer casing with an elastomeric sealing lip that is pressed against the shaft to create a tight seal.
  • Axial lip seals, on the other hand, are designed to provide a barrier against fluid leakage along the axis of rotation. They have a similar design to radial lip seals but are oriented in the axial direction.
  • Mechanical face seals, also known as floating-face or heavy-duty face-type seals, are typically used in more demanding applications where high pressures and extreme temperatures are present. They consist of two metal rings with flat faces that are held together by springs and form a dynamic seal between them.

Materials used

Various materials with unique properties are utilised in the construction of rotary shaft seals, allowing manufacturers to tailor the sealing solution to specific industry requirements and ensure optimal performance.

  • Metal, such as steel, which provides strength and durability.
  • Rubber is also a popular choice due to its flexibility.
  • Elastomers, such as nitrile, viton, and silicone, are often used for their resistance to various chemicals and temperature extremes.
  • Nitrile rubber is suitable for applications involving petroleum-based fluids, while viton seals offer excellent resistance to high temperatures and aggressive chemicals.
  • Silicone rubber seals have good heat resistance but lower chemical resistance compared to other elastomers.

Choosing the correct type for your application

In choosing the right oil seal type for your application, it is essential to assess factors such as speed, temperature range, pressure levels, chemical compatibility, shaft material, and installation space limitations. By considering these factors carefully, you can ensure that you select an oil seal that will provide optimal performance and longevity in your specific application.

Where to buy oil seals in the UK

In the UK, customers have a range of options for purchasing oil seals. There are several reputable UK gasket manufacturers that offer a wide selection of oil seals to meet various industrial needs.

One option is to buy oil seals from specialised gasket and sealing material companies like Polymer Trade Manufacturing Ltd, which is known for its expertise in dealing with gaskets and o rings. These companies not only offer an extensive range of oil seals but also provide expert advice to help customers select the right sealing materials for their specific requirements.

If you need any help or advice simply give us a call or fill in the enquiry form and one of our technical team will help you out.

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