Valves, as key components in fluid control systems, have a sealing performance that directly relates to the safety and efficiency of the entire system. The rubber seal, as the core part of the valve’s sealing mechanism, has a material selection that is crucial for ensuring the reliability of the valve. The following is a detailed comparison and application analysis of different material rubber seals for valves.
NBR Nitrile Rubber Seal
NBR seals are very common in industrial applications due to their wide applicability and lower cost. They are suitable for various hydraulic oils and lubricating oils but are not suitable for polar solvents such as ketones, ozone, nitriles, MEK, and chloroform. The operating temperature range for NBR is from -40°C to 120°C, making it an economical choice.
HNBR Hydrogenated Nitrile Rubber Seal
HNBR seals offer superior chemical resistance and wear resistance compared to NBR, making them particularly suitable for washing machinery and automotive engine systems. They are not suitable for alcohols, esters, or aromatic solvents, with a use temperature range of -40°C to 150°C.
SIL Silicone Rubber Seal
Silicone rubber seals are known for their excellent heat resistance, cold resistance, ozone resistance, and atmospheric aging resistance. They have good insulating properties but relatively poor tensile strength and oil resistance. Suitable for home appliances and products that come into contact with the human body, such as water heaters, irons, microwave ovens, etc., but not suitable for most concentrated solvents, oils, concentrated acids, and sodium hydroxide. The operating temperature range is from -55°C to 250°C.
VITON Fluorocarbon Rubber Seal
Viton seals have better high-temperature resistance than silicone rubber and excellent chemical and weather resistance. They are resistant to most oils and solvents, especially acids, aliphatic hydrocarbons, aromatic hydrocarbons, and animal and vegetable oils. Suitable for sealing requirements in diesel engines, fuel systems, and chemical plants. The use temperature range is from -20°C to 250°C.
FLS Fluorosilicone Rubber Seal
FLS seals combine the advantages of fluorocarbon and silicone rubber, with excellent oil resistance, solvent resistance, fuel oil resistance, and high and low-temperature resistance. They can resist the erosion of oxygen-containing compounds, aromatic solvents, and chlorinated solvents. The use temperature range is from -50°C to 200°C.
EPDM Terpolymer Rubber Seal
EPDM seals have good weather resistance, ozone resistance, water resistance, and chemical resistance, suitable for sealing in alcohols, ketones, and high-temperature steam environments. The use temperature range is from -55°C to 150°C.
CR Chloroprene Rubber Seal
Chloroprene rubber seals are particularly resistant to sunlight and weather, suitable for environments exposed to the atmosphere, sunlight, and ozone, and for sealing parts that are resistant to chemical corrosion. They are not suitable for strong acids, nitro compounds, esters, chloroform, and ketones. The use temperature range is from -55°C to 120°C.
IIR Butyl Rubber Seal
Butyl rubber seals are favored for their excellent air tightness, heat resistance, sunlight resistance, and ozone resistance. They have good resistance to polar solvents such as alcohols, ketones, and esters and can be exposed to animal and vegetable oils or oxidizers. Suitable for chemical-resistant or vacuum equipment. The use temperature range is from -50°C to 110°C.
ACM Acrylic Rubber Seal
ACM seals have excellent resistance to oils, good high-temperature and weather resistance, but relatively poor mechanical strength and water resistance. They are commonly used in automotive transmission systems and power steering systems. Not suitable for hot water, brake fluid, or phosphate esters. The use temperature range is from -25°C to 170°C.
NR Natural Rubber Seal
Natural rubber seals have good wear resistance, elasticity, tensile strength, and elongation at break. However, they are prone to aging in the air and become sticky when heated. They are suitable for use in liquids with hydroxyl ions such as automotive brake fluid and ethanol. The use temperature range is from -20°C to 100°C.
PU Polyurethane Rubber Seal
Polyurethane rubber seals have excellent mechanical properties, wear resistance, high-pressure resistance, and good aging resistance, ozone resistance, and oil resistance, but they are prone to hydrolysis at high temperatures. They are commonly used in high-pressure and wear-resistant sealing parts. The use temperature range is from -45°C to 90°C.
Selecting the appropriate rubber seal material requires a comprehensive consideration of the valve’s operating conditions, including the type of medium, temperature range, pressure level, and chemical compatibility. Each material has its unique properties and application scope, so careful consideration of these factors is necessary when designing and selecting to ensure the long-term stable operation and sealing performance of the valve. By deeply understanding the characteristics of different rubber seal materials, engineers and technical personnel can more accurately choose seals suitable for specific application environments, thereby improving the reliability and efficiency of the entire fluid control system.
