4 Advice to Choose a rubber oil seals

Leakage of fluids such as liquids and gases is one of the main concerns across industries, where they are used as a part of different industrial processes. To avoid this, manufacturers rely on different types of rubber seals and gaskets in equipment responsible for the transmission of these fluids. Thus, nowadays, rubber seals have become an integral part of valves, pumps, pipe fittings, as well as vacuum seals. Does that mean all rubber seals are the same? No, they are not created the same. They differ in designs, materials, and other specifications, too. Thus, several factors must be kept in mind while designing the seals for your industrial applications. The post outlines a few important factors to be considered during the construction of rubber seals and gaskets.

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Important Things to Consider When Designing Rubber Seals and Gaskets
Failure of a rubber seal or gasket may affect the performance of an application. This means you cannot afford to make the wrong choices, isn&#;t it? The following pointers will help you make the right decision regarding these seals:

• Environment of Use: Perhaps, you may agree that frequent gasket replacement can be time-consuming or frustrating, too. To avoid this, it is important to consider the environment where they are supposed to be installed. There are several limitations on materials across industries such as military, food and pharmaceutical. The consideration of the following will help you better:
  • Compatibility with the chemicals to be used
  • The effect of pressure and temperature on the seals
  • The effect of friction as it can cause excessive pressures to develop and tear the seal portion
  • Tolerance stack up of different parts of the seal
• Dimensional Requirements: What is a right sealing? How does it occur? A sealing occurs when the seal is compressed between two surfaces. The compression causes deformation, which helps prevent the leakage of fluid. To achieve this deformation or proper compression, the cross-section of the seal must be larger than its gland depth. If the cross-section is too small or too large, the seal may not compress properly or disrupt the connection between the two mating surfaces.
• Consider the Adhesive Attachment System: Always ensure that the attachment surface is 1/8ʺ wider. The adhesive must be placed on flat surfaces of the substrate and the seal. The thickness of the adhesive must be taken into consideration when designing the rubber seal for your application.
• Total Amount of Load Applied: What is the direction of the load applied? The results can be disappointing if the load applied is more or less than the specified. The total amount of load applied can be easily controlled by managing the shape of the cross-section, or by adding hollow sections or holes in the cross-section.
• Closing Force Required: What is the required closing force for an application? How much closing force will be tolerated by the application? If the seal is designed for tolerating 20 pounds of force at the maximum, it is not suited for an application where it may be subjected to 50 pounds of force. Along with this, you also need to consider the force needed on the seal, surface area, and size of the cross-section.
• Type of Friction to be Endured: When it comes to dynamic moving applications, the friction is mainly distinguished into two types&#; breakout friction and running friction. The breakout friction can cause high pressures to develop if the part movement is intermittent. However, running friction can cause the heat to build up, which may lead to swelling. In both cases, the friction can cause seal failure.

The consideration of all these factors will help you achieve optimum sealing performance. However, if you are unable to make a decision, it is always ideal to approach an experienced manufacturer like SSP Seals, who will help you get it right. The company has been providing rubber gaskets and seals in various specifications to meet complex application requirements.

Nitrile Butadiene Rubber (NBR, nitrile)

NBR, also known as nitrile rubber or nitrile, is the most popular material for an oil seal because of its good resistance to many oils and greases, such as mineral grease and hydraulic oil. Depending on their composition, synthetic oils and greases, such as those based on glycol, can damage NBR rubber materials. Depending on the amount of glycol, a PTFE lip seal may be the best choice. NBR is also unable to cope with contact with acids and solvents. The rubber is suitable for oil and grease at temperatures from -35 °C to 100 °C.

Most ERIKS oil seals, such as the types M, MST, R and RST, are made of NBR as standard.

Fluorine rubber (FKM, Viton&#;)

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FKM or FPM, which is in well-known brand Viton&#;, can withstand higher liquid temperatures of up to 180 ˚C. FKM is highly resistant to strong acids and bases, as well as to synthetic oils and greases. Glycol-based oil and grease, however, can also damage FKM.

Because of the higher temperature resistance of FKM, this material is also chosen for applications where higher speeds play a role, which raise the temperature at the sealing lip considerably. Usually, using FKM will result in a longer life than using NBR. This compensates the higher price of FKM compared to NBR, as an FKM does not have to be replaced as frequently. The low temperature resistance of standard FKM is limited to -15 ˚C.

Polytetrafluoroethylene (PTFE, Teflon®)

PTFE, which is used in the well-known brand Teflon®, is less commonly used, but it is the preferred material for specific rotating seals in the chemical, food and pharmaceutical industries. This material is notable for having a very low frictional resistance and the best chemical resistance. It can also withstand a very wide range of temperatures in these types of seals; -80 ˚C to 200 ˚C. The shafts on which oil seals with PTFE lips are used require a harder and finer finish. Something like an axle sleeve can also be used to meet this requirement.

EPDM

EPDM oil seals are less common. They are used in solvent, hot water and steam applications, EPDM resists low temperatures down to -50 °C and UV radiation well. Some types of EPDM are also suitable for higher temperatures up to +150 °C. EPDM oil seals are usually available upon request.

VMQ (silicone)

VMQ, also known as silicone, is also used for oil seals, but this is less common because the mechanical strength of VMQ is low and this material has poor wear-resistance This makes it less suitable for dynamic applications, but it can withstand fairly low and high temperatures from -60 °C to 200 °C. Many types of VMQ are also suitable for contact with pharmaceutical and food products, so VMQ is an option worth considering. VMQ oil seals are usually available on request.

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