Guide to oil seals for your application

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™)

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.

The oil seals commonly referred to as rotary shaft seals, radial lip seals or shaft seals are extensively used in almost every industry that involves the use of machinery. These seals have a tight function of ensuring that lubricants do not leak while at the same time filtering out contaminants. This article will look at the various categories of the oil seal, their uses and versatility in the modern world. 

Types of Oil Seals 

Seals are made in other designs and of different materials to fit different applications and working conditions. Here are the most common types:

• Single Lip Seals: These seals have one lip which comes into contact with the shaft. They are commonly applied in situations where low pressure exists, and leakage is barely tolerable. Single lip seals as already noted are cheap in design and relatively easy to fix in a BP. Way system.
• Double Lip Seals: Equipped with another lip, these seals are more protective than the previous ones since they both keep the lubricant from spilling over and out and exclude contaminants. The secondary lip also aids in sustaining the primary lip usefulness by filtering out any unwanted substances. 
• V-Ring Seals: These are all-rubber seals which are fixed on the shaft and they turn with the shaft. Continuing on the V-rings’ functionality, they also offer a flinger that moves contaminants away from the sealing area.
• Labyrinth Seals: Labyrinth seals involve a number of ridges and grooves that intertwine, providing a design that makes it very hard for fluids to get past. These seals are applied in applications where metal to metal contact seals would meet their end prematurely. 
• Magnetic Seals: Working under the principle that a magnetic field can be used to suspend a ferrofluid these seals are ideal for no leakage applications such as in a vacuum or precision instrument. 
• Composite Seals: Such seals are usually made of rubber and PTFE or polytetrafluoroethylene which makes them more resistant to chemicals, heat and also more durable. They are suitable to be used in industries with high demanding operations. 

Functions of Oil Seals 

Oil seals perform several critical functions to ensure the smooth operation of machinery: 

• Preventing Lubricant Leakage: In the first instance of their employment, they help to prevent leakage of lubricants within a system with benefiting movement that operates through minimal friction and wear. 
• Excluding Contaminants: Oil seals exclude dirt, dust, water, and any other foreign particles from penetrating through the casings into the machinery, hence ensuring cleanliness of the machinery’s interior. 
• Pressure Retention: The pressure retention, which is provided by oil seals in some applications also enables efficiency and performance of equipment in the system. 
• Reducing Friction: The applied oil seals decrease its friction towards the shaft through offering a smoother surface that leaves less room for friction hence reducing energy use and heat as well. 
• Extending Equipment Life: In this way, oil seals shield internal parts from contaminants and maintain lubrication, thus increasing the longevity of equipment and decreasing the time and money required for repairs. 

Applications of Oil Seals 

Due to their versatile design, oil seals are installed in numerous industries and various types of equipment. Here are some of the key sectors where they play a crucial role:

• Automotive Industry: Automobiles use oil seals around various parts like the engines, transmissions, differentials, and the wheel hubs. They help avoid spilling of oil and help exclude contaminants which are vital for the sound running and durability of the car. 
• Industrial Machinery: In manufacturing plants, applications of oil seals include pumps, gearboxes, motors and hydraulic systems. They ensure the smooth running and dependable service of the equipment by sealing cracks that are prone to leakages and shielding the internal parts from various unhealthy elements. 
• Aerospace: Aerospace engineering applications are some of the most rigorous, especially in aircraft engines and other parts; this is why oil seals used here have to be specially designed to stand up to high temperatures, pressures and overall harsh conditions. They maintain the operational safety of airplanes and other flying vehicles. 
• Agricultural Equipment: The implements like tractors, harvesters and many other agricultural implements are greatly benefited with the help of oil seals as they do not allow dust and dirt to enter into the moving parts of the implement hence they deliver good performance in the field conditions. 
• Marine Industry: Oil seals are used in marine engines, gear boxes and propulsions where they exclude water and retain oil to enhance the functionality and life of the marine equipment. 
• Medical Equipment: Precision medical devices, such as pumps and diagnostic equipment, use oil seals to maintain sterile conditions and prevent contamination. These seals are critical for ensuring the accuracy and reliability of medical instruments.
• Renewable Energy: In wind turbines and solar power systems, oil seals protect the moving parts from harsh environmental conditions, ensuring efficient energy generation and reducing maintenance requirements.

Choosing of the Right Oil Seal 

Choosing the appropriate oil seal for a specific application involves considering several factors: 

• Operating Conditions: Determine the expansion of temperature, pressure, and speed in which the seal will be running. Each kind of seal is designed for a certain range of these parameters. 
• Material Compatibility: Make certain that the seal has the aptitude to operate correctly with the types of lubricants that are used, as well as with all probable contaminants it will come across. Some of the conventional types are nitrile rubber, fluorocarbon, silicone rubber and PTFE. 
• Shaft and Housing Specifications: They also erected steps to ensure that the shaft diameter, the diameter of housing bore and width of seal match in order to accommodate the most appropriate seal to enhance performance. 
• Application Requirements: The special requirements of the application including chemical resistance, low friction or high temperature use should also be taken into consideration. In some cases the seal may need to be specially designed for a particular service or because of the severe conditions it is exposed to. 
• Environmental Factors: Assess the exposure to such natural conditions such as dust, dirt, water and other damaging elements. Select a seal that is suitable to counter these elements In water, foam, sand or any other element choose the seal that will be suitable for the element of the place. 

Installation and Maintenance of Oil Seals

Oil seals can be installed and maintained quite easily If they are not installed properly either because of wrong fixing techniques or due to wear and tear the oil seal needs to be replaced. 

Durability of oil seals also largely depends on its installation and use therefore it must be installed and maintained correctly. Here are some best practices:

• Cleanliness: Also, it is important that the shaft, housing and seal should be cleaned properly and should not have any kind of dirt before fixing it. Any form of contamination in the seal will lead to degradation of the material thus harming the efficiency of the seal. 
• Lubrication: Before installation and especially during early running, coat a thin layer of the lubricant on the seal lips and the shaft. It also adds on the protection of the seal and hence guarantees a healthy commence. 
• Correct Tools: When applying the seal, ensure that you use the right equipment to avoid spoiling the seal, that is deformation of the same. Do not apply excessive force on the seal because it may result in improper alignment or even destruction. 
• Regular Inspection: It is recommended that the seals should be checked at certain time intervals to determine if they are in good condition, leaking or if they have undergone any type of destruction. The issues are detected at an early stage minimally negating their effects to the extent that their rectification results in less severe complications. 
• Replacement: The oil seals of the equipment should be replaced periodically or when they show signs of deterioration. Reliability of high quality seals and regular checks that should be conducted on the machinery will see the machinery’s life span as being prolonged. 

Conclusion

Oil seals are indispensable components in a wide range of industries, providing essential functions that ensure the efficiency, reliability, and longevity of machinery. By understanding the different types of oil seals, their functions, and their applications, you can make informed decisions when selecting and maintaining these critical components. Whether in automotive, industrial, aerospace, agricultural, marine, medical, or renewable energy sectors, oil seals play a vital role in keeping systems running smoothly and efficiently.

Oil seals work by squeezing and retaining lubricant in a thin layer between the lip and the shaft. Perfect sealing is ensured by the hydrodynamic action of the rotating shaft, which in turn produces a slight pump action.

As earlier said, oil seals perform some functions that ensure the functionality of mechanical equipment and extend their lifespan. And how they do this is by retaining lubricants at all cost and not making them escape no matter how high the pressure of the machine is.

The other way oil seals work is by stopping outboard materials that can damage the machine or contaminate its lubricant. The outboard materials that the oil seal will need to stop depend on the application. However, the most common kinds are dirt, moisture, and the particles produced during manufacturing.

Standard petroleum oil has a lifespan of 30 years at 86 degrees Fahrenheit if it’s not 

contaminated with moisture or any other particle. But the same oil will only last for a month at 212 degrees Fahrenheit if it’s contaminated with little water. This is why the function of an oil seal is very evident whenever it’s used.