The O-ring is a torus, or doughnut-shaped object, generally made from an elastomer that seals when compressed or deformed in a gland. There are many imperial and metric o’ring size standards, but few are commonly found in use. Every month we will send you a brief digest of the latest posts with a link where you can read more. 4. Compared to imperial, there are quite a number of metric size standards from around the globe such as; Japanese, British, German, Swedish, French and Italian metric standards. There are a number of ways to prevent o’ring extrusion failure. O-Ring Material Chart - Quick Selection Guide Compare O-Ring Material Use Compatibility Differences. The O-ring seal needs more space to expand. The table below may be used as a rough guide in determining the pressure rating of o’rings and whether back-up rings should be used or not. 3-905). Stiffening the cylinder wall may also help if excess pressure is causing the cylinder to expand, opening up clearance gaps. French and Italian standards are predominantly based on British Standard imperial with slight variations. O-rings can be used for more than preventing air or fluid from passing, … Rubber o’rings are available in various hardness’s. Operating environment and the physical characteristics of the elastomer must be considered. During World War II, the U.S. government took over … less deflection equals a higher value). Australia’s most well stocked supplier of o’rings, rotary shaft seals, hydraulic seals, pneumatic seals and seal accessories. Go to our Back-up Rings page for more information on o’ring back ups. Split-flange assemblies contain four components; a permanent flanged head connected to the tube, an O-ring and two mating clamp halves with four bolts to connect the split-flange. In the 1940s and early 1950s, the O-ring evolved to become the standard seal for hydraulics in … Grading of compounds comes about from the mixing of various fillers, vulcanizing agents, accelerators, aging retardants and other chemical additives to the base polymer which modify and improve the physical properties of the polymer to meet either the requirements of a specific application or for a broad spectrum of applications. O rings are among the most commonly used seals used in machines and equipment because they are cheap, easy to produce, reliable and easy to assemble. The shelf life of an o’ring varies depending on elastomer and storage conditions. [Figure 1] Hydraulic seals used between nonmoving fittings and bosses are normally called gaskets. At the lower extreme, the seal must be able to perform reliably despite the low level of compression; at the upper case, the forces at work should not become so high as to pose a risk of damage. The huge popularity of the O-ring seal dates back to 1939, when Niels A. Christensen was granted a patent for its design. O-rings are common seals used in many manufacturing industries. Chemical Compatibility. 350 bar. The o ring is placed into a groove to secure them in place, and then compressed between two surfaces. 5. O-ring are one of the most commonly used fluid power seals. A seal may consist of more than one component, such as an O-ring and a backup ring, or possibly an O-ring and two backup rings. 1. The O-ring is the brainchild of J. O. Lundberg. Split-flange assemblies contain four components; a permanent flanged head connected to the tube, an O-ring and two mating clamp halves with four bolts to connect the split-flange. So Martin’s Rubber has compiled this useful O-ring material selection guide, to give you a clear insight into the advantages and disadvantages of common O-ring materials. The - As an axial static seal, e.g. They are used to offer structural support, absorb energy, transmit energy, ‘transmit a fluid’, and ‘seal a fluid’. 2-230). Usually, O-rings are utilized to keep the air or fluid IN/OUT of distinct space. The O-ring is a doughnut-shaped circular cross section seal that can be used nearly anywhere in the sealing industry. Copyright © 2014 Sealing Australia. The elastomeric O-ring sits in a groove on a flange and mates with a flat surface on the port. The most common imperial standard is British Standard BS1806, which is equivalent to American Aerospace Standard AS568A. The O-ring is one of the important and simplest types of seals used in various dynamic, as well as static applications. Please see our O’ring Size page for a comprehensive list of BS1806/AS568A, SAE and JIS metric sizes. Type A readings are used for most common O-ring and seal materials. DIN 3852-1 (ISO 9974-1) Port Style. Glide ring seal with an O-ring energizer for light- to medium duty applications, made of PTFE 40% bronze with an NBR O-ring. Modification. Typical flange applications use the O-ring to seal the joint to contain pressurized fluid in split-flange fittings. O-ring compatibility plays a critical role in o-ring performance – find the right material for your application and avoid o-ring failures. Nitrile NSF 61 is certified by NSF / ANSI standard 61 and is safe for use in water systems where drinking water may come in contact with the seal. Hydraulic seals used internally on a sliding or moving assembly are normally called packings. Both Shore A and IRHD hardness values are comparable, the difference being IRHD is assumed to have a higher accuracy. Also called NBR or Buna-N, nitrile o rings are probably the most economical and widely used elastomer out there. More than this, the… The force needed to compress the seal is produced by the cross-section diameter, and the durometer. Figure 1. At Brennan Industries we have a wide variety of O-ring and seal options available, along with custom stocked O-ring replacement kits. Sealing Australia stocks a wide range of o’rings from 40 Duro to 90 Duro. The groove must be designed to accommodate not just the o’ring size, but also its intended usage; be it dynamic or static operation, radial or axial loading, vacuum or high pressure. There’s also boss seal o’rings for SAE straight thread fittings (also known as 3-series or dash-9; e.g. Grades for pharmaceuticals, semiconductors, resistance to radiation, resistance to explosive decompression and many more. These are intended for use in basic design consideration and to understand the core principles involved in o-ring gland/groove design. Figure 4 – ISO 6149-1 combinations. The Quad-Ring™, a 100% retrofit option for any O-ring application, can and will outperform an O-ring in many technical areas. This device is pressed against the rubber. Careful planning prior to specification is vital for a successful o’ring seal design. You are probably aware that O-rings play an important role in push fit fittings in the plumbing industry. One of the most widely used devices today is the O-ring. This cross section provides an initial compression. These are primarily applications in the chemical, food, pharmaceuticals and medical industries. IATF16949:2016 An o’ring is a torus shaped ring (like a doughnut) that is used to prevent leakage of fluids and gases by filling a clearance gap between two mating hard surfaces with a … Generally speaking, O-rings are used as static seals. With such a broad range of materials available, it can be tricky to select the appropriate material for any given project. 30 x 3 instead of 29.4 x 3.1 as found in JIS). Nitrile O-Ring Materials Page. In 1937, the first patent for an O-ring in the United States was filed by professional machinist Niels Christensen. O-ring seals are typically used for sealing spool valves and for pistons in pneumatic cylinders and similar reciprocating applications. There are two common standards for measurement of rubber hardness: Shore Durometer (specifically Shore A Durometer) and International Rubber Hardness Degrees (IRHD). We are often asked what is the pressure rating of an o’ring. The O-Ring is used predominantly for staticand special applications allow the O-Ring to be used to sealing applications:seal practically all liquid and gaseous media. Apply a reasonable safety factor in practical applications to allow for excessively sharp edges and other imperfections and or higher temperatures. The most common metric size standard in Australia is the Japanese JIS-B2401 standard with piston, gland and vacuum sizes (P, G & V). There are grades for contact with food, drinking water and sewerage. Both the non-adjustable and adjustable styles use a single, round cross section O-ring and, when properly assembled, the O-ring is squeezed down into the gland of the port thereby creating a very effective seal. The Quad-Ring™ has four definitive sealing advantages over an O-Ring: Here, we’ll look at Viton™ vs nitrile o rings to see where each should be used, and why. Total diametrical clearance must include cylinder expansion due to pressure. Also to be considered are the mechanical and physical properties of the o’ring elastomer, especially of concern in a dynamic application where movement is involved. Brennan has locations worldwide, including 13 strategically located distribution centers. FIGURE 2Maximum principal deformation in the material … Both have the same three digit size reference (e.g. AS/NZS 4020 To ensure maximum shelf life of an elastomer, o’rings should be stored: Go to our Elastomer Application Guide for information on elastomer shelf life. For example, My underwater camera uses O-rings to keep water out and my SCUBA regulator uses O-rings to prevent precious air from escaping. An ‘O’ ring seal is a moulded elastomeric ring ‘nipped’ in a cavity in which the seal is located. The Type D scale is used for harder materials such as filled thermoplastics. ISO 9001:2015 The O-ring flange is attached to the port using the mounting bolts to tighten down the O-ring flange onto the flange clamps. O-rings are very commonly found in pumps, cylinders, connectors and valves, helping to seal joins between separate parts and prevent leaking of fluids and gases. But the O ring is also manufactured, for example, in PTFE, other thermoplastic materials and in metal, both solid and hollow. Teflon O-Rings ,Polytetrafluoroethylene (PTFE) is used wherever the chemical and thermal resistance of the elastomer O-Rings is no longer sufficient. Measurement is taken with a device which uses a ball or cone indenter connected to a spring and gauge. 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