NBR Backup Ring: What it is and How it Works

If you're looking for a reliable way to prevent O-ring extrusion, NBR backup rings are a great solution. These rings are made from a hard NBR material and are designed to work in tandem with O-rings to provide additional support and prevent extrusion. They are particularly useful in high-pressure applications where O-rings are more likely to fail due to extrusion.

NBR backup rings are compatible with a wide range of oils and gases, making them a versatile solution for a variety of industrial applications. They come in a range of durometers and sizes, allowing you to choose the perfect backup ring for your specific needs. In addition to providing support for O-rings, they also help to distribute pressure more evenly across the sealing surface, reducing the risk of leaks and other issues.

Overview of NBR Backup Rings

Definition and Purpose

NBR backup rings are supportive elements used in sealing systems, typically with devices like O-rings. These rings fit in the groove or gland of a seal, where their distinct shape and rigidity prevent the O-ring from entering the clearance gap during high-pressure operations. A backup ring is a robust, hardened ring that supports the O-ring, preventing extrusion and increasing the service life of the seal.

Material Composition

NBR backup rings are made of nitrile rubber (NBR) with a 90 Durometer hardness as standard. Nitrile rubber is a synthetic rubber copolymer of acrylonitrile (ACN) and butadiene. It has excellent resistance to oil, fuel, and other petroleum-based products, making it ideal for use in hydraulic and pneumatic systems. NBR backup rings are also resistant to abrasion, tearing, and compression set, ensuring long-lasting durability.

NBR backup rings are available in various shapes, sizes, and configurations to suit different sealing applications. They can be used in conjunction with other sealing elements like O-rings, piston seals, and rod seals to provide superior sealing performance in high-pressure and high-temperature environments.

In summary, NBR backup rings are essential components in sealing systems that prevent extrusion and enhance the service life of seals. They are made of high-quality NBR rubber, which provides excellent resistance to oil, fuel, and other petroleum-based products. If you are looking for a reliable and durable backup ring, NBR backup rings are an excellent choice.

Design Considerations

When designing an NBR backup ring, there are several important considerations to keep in mind. These considerations include sizing and dimensions, tolerance, and fit.

Sizing and Dimensions

NBR backup rings are available in a range of sizes and dimensions to fit various applications. It is important to select the appropriate size and dimension for your specific application to ensure optimal performance. The size and dimensions of the backup ring should be chosen based on the size of the O-ring or seal that it will be used with.

Tolerance and Fit

When selecting an NBR backup ring, it is important to consider the tolerance and fit of the ring. The tolerance refers to the allowable deviation from the specified dimensions, while the fit refers to how tightly the backup ring fits within the gland.

It is important to ensure that the tolerance and fit of the backup ring are appropriate for the specific application. A backup ring that is too loose may not provide adequate support to the O-ring, while a backup ring that is too tight may cause excessive friction and wear.

Overall, when designing an NBR backup ring, it is important to carefully consider the sizing and dimensions, tolerance, and fit to ensure optimal performance and longevity.

Installation Procedures

Preparation and Handling

Before installing an NBR backup ring, you need to ensure that the ring and the groove are clean and free of any debris or contaminants. Any debris or contaminants can cause the backup ring to fail prematurely, leading to seal failure. Therefore, it is essential to clean the groove and the backup ring thoroughly.

When handling the backup ring, you should avoid touching the sealing surface with bare hands. The oil from your skin can cause the backup ring to slip out of place or cause it to fail. Therefore, it is recommended to use gloves when handling the backup ring.

Step-by-Step Installation

1. Start by cleaning the groove and the backup ring thoroughly. You can use a lint-free cloth or a cotton swab to remove any debris or contaminants.
   
   
2. Lubricate the backup ring and the O-ring with the appropriate lubricant. The lubricant will help the backup ring slide into place and prevent it from getting damaged during installation.
   
   
3. Install the O-ring into the groove first. Ensure that the O-ring is seated correctly and is not twisted or pinched.
   
   
4. Install the backup ring into the groove. Ensure that the backup ring is seated correctly and is not twisted or pinched.
   
   
5. Check the backup ring and O-ring for any damage or defects before installing the mating part.
   
   
6. Install the mating part into the groove, compressing the O-ring and the backup ring.
   
   
7. Check the seal for any leaks or damage.
   
   

By following these step-by-step installation procedures, you can ensure that the NBR backup ring is installed correctly and will provide reliable sealing performance.

Operational Performance

Pressure and Temperature Limits

NBR backup rings are designed to withstand high-pressure environments. They are capable of handling pressures of up to 5,000 PSI and can operate at temperatures ranging from -40°C to 120°C. However, it is important to note that the pressure and temperature limits may vary depending on the specific application and the type of fluid being used.

To ensure optimal performance, it is recommended that you consult the manufacturer's specifications and guidelines before installing NBR backup rings in your system. This will help you determine the appropriate pressure and temperature limits for your specific application.

Durability and Lifespan

NBR backup rings are known for their durability and long lifespan. They are resistant to abrasion, chemicals, and most oils and greases. This makes them ideal for use in a wide range of applications, including hydraulic and pneumatic systems.

With proper installation and maintenance, NBR backup rings can last for many years. It is important to regularly inspect and replace them as needed to ensure optimal performance and prevent system failures.

In summary, NBR backup rings are a reliable and durable solution for high-pressure sealing applications. By following the manufacturer's guidelines and properly maintaining them, you can ensure long-lasting and efficient performance in your system.

Maintenance and Replacement

Regular maintenance of NBR backup rings is important to ensure optimal performance and prevent downtime. In this section, we will discuss the inspection guidelines and replacement criteria for NBR backup rings.

Inspection Guidelines

Regular inspection of NBR backup rings is necessary to detect any wear and tear that may affect their performance. Here are some guidelines to follow when inspecting NBR backup rings:

• Check for any visible damage, such as cracks, cuts, or deformation.
• Inspect the surface of the backup ring for any signs of wear or abrasion.
• Check the O-ring groove for any damage or deformation that may affect the seal.
• Ensure that the backup ring is properly seated in the O-ring groove.

If any of the above issues are detected during inspection, it is recommended to replace the backup ring.

Replacement Criteria

NBR backup rings should be replaced if they show any signs of damage or wear that may affect their performance. Here are some replacement criteria to follow:

• If the backup ring is cracked or deformed, it should be replaced immediately.
• If the surface of the backup ring shows signs of wear or abrasion, it should be replaced.
• If the backup ring is not properly seated in the O-ring groove, it should be replaced.

It is important to note that NBR backup rings should be replaced with backup rings of the same size and material to ensure compatibility with the O-ring and prevent any leakage.

In conclusion, regular inspection and replacement of NBR backup rings is important to ensure optimal performance and prevent downtime. By following the guidelines and criteria discussed in this section, you can ensure that your NBR backup rings are functioning properly and prevent any potential issues.