What Is an O-Ring and the Most Common Types of O-Rings

What Is an O-Ring and the Most Common Types of O-Rings

You must have often seen those tiny doughnut-shaped rubber bands and wondered what they are used for and how they help machines and engines, right? These little miracles are called O-rings. Though sometimes made of small rubber or metal and most often seen in engineering and industry, they are a significant component regardless of size. 

The power of O-rings is pretty remarkable, although their shape is rather simple. Furthermore, these small wonders are utilized to seal fluids and gasses, which means they have a broad range of applications. Additionally, a solitary O-ring can withstand a lot of pressure.

Some O-rings are rated for pressures of around 10,000 psi (pounds per square inch). This is possible due to their unique design and the materials used in O-ring manufacturing. These materials can withstand high temperatures, chemicals, natural wear, and other similar factors, ensuring an O-ring is suitable for every job.

What is an O-Ring?

O-rings are round seals with a cross-section shaped like a circle made of rubber or silicon. They are used to prevent gases and liquids from flowing through machines and equipment. Such rings fit in the groove and then squeeze between two parts, tightly sealing them.

These rings are known for their low cost, ease of manufacture, dependability, and simplicity of fitting. This is one reason they are also known as elastomer O-rings or rubber rings.

What is an O-Ring?

Parker Hannifin Corporation, an influential company specializing in motion control technologies, states, “O-rings are circular seals that prevent liquid or gaseous substances from leaking out of engine parts such as pumps.” The company further explains that these sealing systems sit inside grooves pressurized by two adjacent mechanical components so that the edges meet.

O-rings are essential components in many devices, instruments, and machinery. They are highly valued for their ability to withstand pressure and cost-effectiveness, making them excellent for creating strong seals. O-rings are placed in a groove and compressed to form a seal, preventing the escape of liquids or gases.

5 Common Types of O Rings & Their Usage

Each type of rubber offers unique properties that make it ideal for specific applications. Here's a breakdown of some of the most common O-ring materials:

1. Nitrile Rubber (NBR)

This is a synthetic rubber copolymer made from acrylonitrile and butadiene, and it is commonly called Nitrile Rubber. It finds application in sealing technology due to its resistance to various chemical substances like oil and fuel.

Also known as Buna-N or acrylonitrile butadiene rubber, Nitrile rubber is one of the toughest materials for seals. Because of this, it can be used over long periods in difficult conditions

It can tolerate temperature fluctuations but works best on objects that come into contact with deadly chemical solvents and corrosive.

Common Uses of Nitrile Rubber

Common Uses of Nitrile Rubber:

  • Aircraft fuel systems
  • Automotive fuel systems
  • Off-road equipment
  • Marine fuel systems
  • Lab cleaning equipment
  • Examination gloves

    2. Viton (FKM or FPM)

    Fluoroelastomer, also known as FKM, FPM, and Viton®, is a synthetic rubber material family. The name comes from "Fluoro" for Fluoro, "K" from the German word "Kohlenstoff" meaning Carbon, and "M" designates saturated backbone rubber according to ASTM standards.

    FPM is the international ISO 9000 and ISO/TS 16949 standard registration for Fluoroelastomers.

    Six major monomers used to create various types of Fluoroelastomers

    There are six major monomers used to create various types of Fluoroelastomers:

    • Ethylene (E)
    • Hexafluoropropylene (HFP)
    • Perfluoro Methyl Vinyl Ether (PMVE)
    • Propylene (P)
    • Tetrafluoroethylene (TFE)
    • Vinylidene Fluoride (VDF)

      3. Silicone (VMQ)

      Silicone (VMQ) O-rings are elastomers made from silicone, oxygen, hydrogen, and carbon. Silicones are commonly used in the medical and food industries because they are odorless and tasteless. 

      VMQ is resistant to various substances, including oxygen, ozone, UV light, mineral and vegetable oils, diluted salt solutions, engine and transmission oil, non-petroleum-based brake fluids, fire-resistant hydraulic fluid, and high molecular weight chlorinated aromatic hydrocarbons.

      Advantages of Silicone (VMQ) O-rings

      Advantages of Silicone (VMQ) O-rings include:

      • Temperature range of -60°F to 400°F, with some formulations up to 450°F
      • Physiologically neutral properties
      • Good insulation properties
      • Excellent resistance to ozone and weather conditions
      • Compatible with food grade standards
      • Electrical insulation and compatibility

        4. Ethylene Propylene Diene Monomer (EPDM)

        EPDM, or Ethylene Propylene Diene Monomer, is a type of synthetic rubber known for its lower cost and resistance to steam and chemicals, making it suitable for applications involving sealants, solvents, acids, and other mild chemicals. It is a versatile yet affordable rubber with a wide range of uses.

        EPDM is commonly used in roofing for waterproofing because it forms effective seals. It is also frequently used for seals in freezer rooms because of its insulation properties and excellent tolerance to low temperatures.

        EPDM is primarily used in the plumbing, electrical, automotive, and construction industries.

        Common applications of EPDM

        Some common applications of EPDM O-rings include:

        • Automotive brake & cooling systems
        • Seals for doors, windows, and trunks
        • Water pumps and flow systems
        • Plumbing pipes and fittings
        • EGR valves and coolers
        • Heaters, oil coolers, and radiators
        • Medical devices
        • Electronic appliances

          5. Polytetrafluoroethylene (PTFE)

          Polytetrafluoroethylene, or PTFE, is a versatile material known for its density, hydrophobic properties, and resistance to high temperatures. These characteristics make PTFE an excellent choice for commercial and industrial O-rings.

          While most O-rings are typically made from rubber-like elastomeric materials, PTFE is the preferred choice for extreme environmental conditions, such as high-temperature or very low-temperature settings. PTFE, a versatile plastic polymer with a high molecular weight, is dense and long-lasting. It maintains its flexibility and durability in temperatures ranging from close to zero to 250°C.

          Manufacturers can easily create and shape PTFE O-rings to meet precise dimensions and requirements.

          Common applications of PTFE

          Common applications of PTFE O-rings include:

          • Valve stems
          • Flanges
          • Pumps
          • Swivels
          • Joints

            Get Your Quality O-Ring with Hydraulic Warehouse

            We at Hydraulic Warehouse emphasize quality and ensure that our products undergo stringent quality tests. Purchasing from unfamiliar brands can pose risks to your machines and engines.

            Explore common O-ring materials such as backup rings, reliable seals like Nitrile Rubber, Viton, Silicone, EPDM, Polytetrafluoroethylene (PTFE), etc. We are here to help you determine which one best suits your needs.

            Additionally, you may explore our range of quality products, including:

              Find these and more quality products in our store!

              Final Thoughts

              Choosing the correct O-ring material is very important for achieving good sealing performance. The choice is influenced by several design factors such as size, squeeze, stretch, chemical compatibility, and the ability to resist pressure, temperature, and friction that keep everything tightly sealed.

              So, next time you see one of those small rubber circles, give it a nod of appreciation for all the hard work it does behind the scenes. Don’t forget that O-rings are your reliable seal and the MVPs when it comes to keeping things sealed up tight!

              Key Takeaways:

              • O-ring seals are simple yet powerful : These tiny rubber rings prevent leaks in various applications by creating a tight seal between two surfaces. They come in different materials to handle extreme temperatures and harsh chemicals.
              • Rubber rings work through compression, conformity, and elasticity: They deform to form a seal when squeezed between surfaces. Their ability to conform to imperfections and return to their original shape ensures long-lasting leak prevention.
              • Rubber O rings are vital across numerous industries: From keeping your car running smoothly to ensuring safe medical procedures, rubber O-rings can be used in various applications, ensuring machinery and equipment function efficiently.
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