An O-ring is a loop of elastomer/rubber with a round cross-section, designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal.
The O-ring may be used in static or dynamic applications where relative motion exists between the parts and the O-ring. Dynamic examples include rotating pump shafts and hydraulic cylinder pistons.
O-rings are one of the most common seals used in machine design because they are inexpensive, easy to make, reliable, and have simple mounting requirements. They can seal tens of megapascals (thousands of psi) of pressure.
Common Uses:
O-rings are found in a wide range of industries, including:
- Waterworks
- Military & Defence
- Medical &life sciences
- Semiconductor
- Agriculture
- Food processing
- Oil & Gas
- Chemicals
- Automotive
O-Ring
What Is an O-Ring Good For?
The versatility of the O-ring is evident in its broad range of applications. Here are some of its key uses:
- Leak Prevention: O-rings are designed to seal gaps between two mating surfaces, effectively preventing fluids and gases from escaping in systems like hydraulic cylinders, pumps, and valves.
- Dynamic and Static Sealing: Whether the sealing surfaces are stationary or in relative motion, O-rings provide reliable performance, making them suitable for applications involving vibration or movement.
- Cost-Effective and Durable: With a simple design and low production cost, O-rings offer an economical sealing solution while maintaining durability and performance under various operating conditions.
Rubber O Rings
Choosing the Right O-Ring: Size and Material Considerations
Selecting the appropriate O-ring involves careful consideration of both its physical dimensions and the properties of the material:
- Size and Fit
- Standard Sizing: O-rings are available in standardized sizes (such as those defined by ISO 3601 or SAE standards), which simplifies selection for many applications.
- For AS-568 Dimensions: https://www.technoad.com/engineering/dimensions/as-568-parker/
- For ISO 3601Dimensions: https://www.technoad.com/engineering/dimensions/iso-3601/
- Measurements: The two critical dimensions are the inner diameter (ID) and the cross-sectional diameter (CS). These must match the groove dimensions in the application to ensure proper compression and sealing.
- Tolerance and Compression: Proper sizing also involves understanding the amount of compression (or squeeze) required for an effective seal. Too little compression might result in leaks, while too much can lead to premature wear or damage to the O-ring.
https://www.technoad.com/engineering/gland-designhttps://www.technoad.com/engineering/dimensions/
- Material Selection
- Chemical Compatibility: The choice of material should be compatible with the fluids or gases in the system. https://www.technoad.com/engineering/material-selection-guide
- Temperature Range: Different materials have varying temperature limits. Ensure that the selected O-ring can handle both the minimum and maximum operating temperatures of your application.
- Pressure Ratings: Consider the operating pressure of your system. Some materials are more resistant to high-pressure environments and are less likely to extrude (i.e., get forced out of the groove under pressure).
- Wear and Life Expectancy: For applications with dynamic movement, choose materials known for their wear resistance and longevity.
O Ring Seal
Types of elastomers
- NR – Natural rubber
- NBR – Acrylonitrile butadiene, Nitrile or Buna N
- HNBR – Hydrogenated nitrile, or highly saturated nitrile
- XNBR – Carboxylated nitrile
- NBR/PVC – Nitrile/PVC resin blends
- EPM, EPDM – Ethylene Propylene, and Ethylene Propylene Diene rubber
- CR – Neoprene, Polychloroprene
- IIR – Butyl
- SBR – Styrene-Butadiene
- VMQ – Silicone
- FVMQ – Fluorosilicone
- AU, EU – Polyurethane
- FKM – Fluorocarbon elastomer (Viton™)
- FFKM – Perfluorocarbons elastomer (Kalrez®)
- PTFE – Polytetrafluoroethylene (Teflon™)
- FEP – Fluoroethylenepropylene, is the melt-processable version of PTFE
- PFA– Perfluoralkoxy, is a high temperature version of FEP
- TFE/P – Tetrafluoroethylene Propylene (Aflas®) (FEPM)
Techno Ad – Explore the Possibilities
Techno Ad offers O-rings in a wide array of sizes (AS568, ISO 3601, BS 4518, GB, JIS, SMS 1586, millimetric and non-standard sizes) and in various properties (hardness, compression-set, etc.),materials, and standard and certified compounds for drinking water, medical device, military / defense, etc. Additionally, we can supply O-rings that adhere to the highest military specifications, FDA, NSF61, and other standards.
Our extensive stock of O-rings includes over 10,000 different sizes and 30 million total pieces, including Viton™ and Kalrez®.
Small minimum order quantities (MOQ) can be processed for in-stock O-rings.
New tooling can be manufactured to produce a special size per customer’s drawing – ask us for a quotation.