Understanding the Mechanics of Bonded Seals - A Technical Overview

Understanding the Mechanics of Bonded Seals - A Technical Overview

When it comes to leak-proof sealing solutions, bonded seals have become the go-to solution across many industries. These seals comprise a metallic washer and an elastomer seal that is bonded together, creating a secure seal that can withstand high-pressure applications.

The principle behind bonded seals is easy to understand. However, to better appreciate the effectiveness of these seals, one needs to have an adequate understanding of their mechanics. In this article, we will explore the mechanics of bonded seals while examining their applications, benefits, and limitations.

What are Bonded Seals?

Bonded seals, also known as Dowty seals, are typically made from fluorocarbon, nitrile, or silicone elastomers. These seals are designed to be pressed against two surface faces, creating a reliable and leak-proof seal.

The metallic washer portion of the bonded seal plays a key role in the sealing process. The washer ensures that the elastomeric seal is compressed between two surfaces, which then creates a tight seal resulting in no leakage.

One of the significant advantages of bonded seals is their ability to conform to imperfections and surface irregularities on the joined surfaces. Elastomeric seals tend to flow into the surface irregularities, which then leaves the crevices filled and void spaces filled up by air closed.

The Mechanics Behind the Bonding Process

Creating a high-quality bonded seal requires specific manufacturing processes that depend on the type of elastomer used and the size of the metallic washer. Preparing the metallic washer is the first step in the bonding process.

The washer is washed with a degreasing fluid to remove particles and oil on its surface. An etching process follows, which is used to clean and roughen the surface of the washer. This is done to create a suitable surface for the bonding agent and ensure that the bonding process creates maximum adhesion between the metallic washer and the elastomer.

Next, the washing-infused metallic washer is applied with a coat of primer, which will enhance the bonding process. This primer layer is then cured before the application of an adhesive layer. The adhesive is added as a liquid and then cured, causing the elastomer to stick to the metallic washer―resulting in a solid and reliable bonded seal.

Benefits of Bonded Seals

Bonded seals have become one of the leading sealing solutions for various industries. Over time, these seals have proven their effectiveness by providing several benefits, which include:

1. High Pressure Performance

Bonded seals have a high-pressure rating, making them ideal for applications that require high-pressure levels. This pressure is sustained due to the combined forces exerted by the metallic washer and the elastomeric seal, resulting in a leak-proof seal.

2. Long-lasting durability

Bonded seals are known for their durability. The elastomeric seal has a good resistance to wear and tear and adverse environmental factors, such as UV rays.

3. Heat resistant

Bonded seals are also heat-resistant, making them ideal for applications in high-temperature areas. The seals can withstand temperatures ranging from negative 60 degrees Celsius to 200 degrees Celsius.

4. Chemical-resistant

Bonded seals are resistant to chemicals such as fuels, oil, and hydraulic fluids, making them ideal for applications in the automotive and aerospace industries.

Limitations of Bonded Seals

While bonded seals have a wide range of applications, they also have limitations that must be considered when deciding on their use. These include:

1. Limited sizes

Bonded seals come in specific sizes, which can limit their applications. For custom sizes, manufacturers may add a polymer film to the elastomer material, making them bulky and reducing sealing efficiency.

2. Handling requirements

Due to their fragile nature, bonded seals require proper handling and cautious transportation. Any form of rough handling may damage them, leading to seal failure.

3. High Manufacturing Cost

The manufacturing process for bonded seals is expensive due to the specific processes involved, making them costly than other sealing solutions.

Applications of Bonded Seals

Bonded seals are used in various applications because of their effectiveness in providing leak-proof sealing. Some of the applications include:

1. Automotive Industry

Bonded seals are used for automotive applications such as engine and transmission oil systems, fuel systems, and power steering systems.

2. Aerospace Industry

Bonded seals are used for aerospace applications such as hydraulic systems and fuel systems due to their chemical and temperature-resistant properties.

3. Industrial Applications

Bonded seals are used in industrial applications such as pipelines, pumps, and hydraulic systems, to name a few.

Conclusion

In conclusion, understanding the mechanics of bonded seals is critical when choosing a sealing solution for different industrial applications. The combination of the elastomeric seal and metallic washer creates a strong and durable seal that can withstand high pressures. Bonded seals have proven effective in several industries, such as automotive and aerospace, providing leak-proof sealing with their high-temperature and chemical-resistant properties. However, the high manufacturing cost and limited sizes of bonded seals need to be considered when deciding on their use.