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Hydraulic Seals Suppliers are true all-rounders in industry and everyday life – they have use in almost every imaginable industry and, depending on the material, meet the most diverse requirements.
This article gives you a helpful overview of the 11 most important materials, from which hydraulic seals are typically made, as well as their properties and possible applications.
Hydraulic Seals are ring-shape seals. The term O-ring comes from the round, O-shaped cross-section of the ring, alternatively the terms round ring or zero ring are there. In many countries, O-rings are standardized according to DIN ISO 3601 and the size is specified as the inner diameter x the cord diameter. O-rings have composition of various standard sizes, but special dimensions are also possible.
O-rings are the most common seals – they are very reliable and easy to assemble and therefore particularly popular for industrial use. The sealing rings usually manufacture of elastomers (rubber), but O-rings of plastics or metals are also possible. In this article we mainly refer to the different materials made of rubber.
Hydraulic Seals Suppliers have use in many areas of industry. As the primary sealing element in a groove, the O-ring prevents liquids or gases from escaping. The O-ring obtains its sealing effect between the two partial areas through compression and adapts well to tolerances due to its flexibility.
The O-ring has most frequently use in the static area, as it has proven to be foolproof there: If the sealing points have correct design, an installation error is unlikely, but the O-ring also seals reliably with smaller errors.
O-rings have also use in dynamic applications, for example as piston or rod seals in hydraulic cylinders. They develop their effect best in this area with short strokes and small diameters.
If you compare the O-ring with other sealing elements, it has the following advantages:
Hydraulic Seals Suppliers from many different materials, on which the properties of the particular O-ring depend. In the following we list the best-known materials for O-rings as well as their properties and typical areas of application:
Acrylonitrile Butadiene Rubber (NBR)
Acrylonitrile butadiene rubber is under the brand name Perbunan N (formerly Buna N). Since NBR has a very good resistance to vegetable and animal oils and fats as well as good mechanical properties, the typical field of application of these O-rings is hydraulics.
NBR O-rings have also use in a temperature range from approx. -20 to +100 ° C and briefly up to 120 ° C. However, use at high temperatures accelerates the aging of the ring.
Chloroprene rubber (CR) or neoprene (NE)
Chloroprene rubber is very common-speaking countries under the name neoprene and is one of the first synthetic rubbers to develop. O-rings made from this material have good ozone, weather, chemical and aging resistance and are good flame retardant. Since the rings also have good resistance to refrigerants, they are also often used in air conditioning units. At high temperatures in atmospheric oxygen, the hardness of the O-ring increases.
They have use in a temperature range of approx. -40 to +100 ° C and briefly up to 120 ° C.
O-rings made of EPDM are resistant to hot water and steam, brake fluids, detergents and silicone oils and greases. Caution is advised with mineral oils and animal fats such as milk. Hydraulic Seals Suppliers are considered safe in connection with food in connection with a corresponding approval, such as FDA conformity, and are therefore often found in the food industry.
The resistance lies in a temperature range between approx. -50 to +150 ° C and can be up to approx. +180 ° C for special qualities.
Fluorocarbon rubber (FKM)
FKM has name as Viton®, which is the name of the “DuPont Performance Elastomers”. It is one of the most important material developments because the material has a wide range of possible uses and, in conjunction with a corresponding approval, is also suitable for food applications. FKM O-rings have use, for example, as seals for detachable flange connections in vacuum technology.
O-rings made of FKM have use in a temperature range of approx. -20 to +200 ° C.
Fluorosilicone rubber (FVMQ)
In addition to the typical properties of normal silicone rubber, fluorosilicone rubber also has improved resistance to oils, fuels and solvents and, in particular, to aromatic and chlorinated hydrocarbons and alcohols. Another property is the very good resistance to low temperatures. O-rings made from this material have most use in static environments and are of use in aerospace applications.
The optimal temperature range for using the FVMQ-O-rings is approx. -55 to +175 ° C.
The hydrogenation connects hydrogen atoms with the double bond of the butadiene molecules. This has the advantage of an increased thermal load capacity of the O-rings made of HNBR. In addition to being ozone and weather resistant, they are also resistant to vegetable and animal fats and oils. Hydraulic Seals Suppliers withstand solutions and emulsions with the designation HFA, HFB and HFC.
These O-rings have use in a temperature range of approx. -20 to +150 ° C.
Perfluoro rubber (FFKM)
FFKM is a high-temperature material and has particularly good resistance to almost all chemicals. For this reason, it has often use where other O-rings fail or where the service life would be short-lived. FFKM O-rings are most often used in chemical plants, oil production or in high pressure and valve areas.
The FFKM-O-rings can be used in a temperature range of approx. -15 to +310 ° C.
O-rings made of polyurethane rubber are particularly characterized by their high wear resistance in connection with mineral and silicone oils as well as ozone pollution. They have a high level of performance in terms of tear and abrasion resistance as well as elasticity.
The EU material has better hydrolysis resistance than the AU material and is therefore ideally suited for use with aqueous media.
The temperature range of the polyurethane materials extends from approx. -40 to +90 ° C.
Hydraulic Seals Suppliers provide seals which are universally resistant to alcohols, bases, benzines, ketones and aggressive acids and offer very good sliding properties. Another advantage is that PTFE O-rings show little wear and thus have a long service life.