How to choose sealing ring for hydraulic system?
1, 1. Material: It is the most widely used and lowest cost rubber seal. Not suitable for use in polar solvents such as ketones, ozone, nitrohydrocarbons, MEK and chloroform.Not suitable for use in polar solvents such as ketones, ozone, nitrohydrocarbons, MEK and chloroform. The general use temperature range is -40~120 ℃. Second, HNBR hydrogenated nitrile rubber sealing ring has excellent corrosion resistance, tear resistance and compression deformation characteristics, ozone resistance, sunlight resistance, weather resistance is good. Better wear resistance than nitrile rubber. Suitable for washing machinery, automotive engine systems and refrigeration systems using the new environmentally friendly refrigerant R134a. Not recommended for use in alcohols, esters, or aromatic solutions. The general use temperature range is -40~150 ℃. Third, FLS fluorine silicone rubber sealing ring has the advantages of fluorine rubber and silicone rubber, oil resistance, solvent resistance, fuel oil resistance and high and low temperature resistance are good. It is resistant to the attack of oxygen containing compounds, aromatic hydrocarbon containing solvents and chlorine containing solvents. It is generally used for aviation, aerospace and military purposes. Exposure to ketones and brake fluids is not recommended. The general use temperature range is -50~200 ℃.
2, performance: In addition to the general requirements of the sealing ring material, the sealing ring should also pay attention to the following conditions: (1) elastic and resilient; (2) Appropriate mechanical strength, including expansion strength, elongation and tear strength. (3) The performance is stable, it is not easy to swell in the medium, and the thermal contraction effect (Joule effect) is small. (4) Easy to process and shape, and can maintain a precise size. (5) does not corrode the contact surface, does not pollute the medium, etc. The most suitable and most commonly used material to meet the above requirements is rubber, so the sealing ring is mostly made of rubber material. There are many varieties of rubber, and there are constantly new rubber varieties, design and selection, should understand the characteristics of various rubber, reasonable choice.
3, advantages: 1, the sealing ring in the working pressure and a certain temperature range, should have good sealing performance, and with the increase of pressure can automatically improve the sealing performance. 2. The friction between the sealing ring device and the moving parts should be small, and the friction coefficient should be stable. 3. The sealing ring has strong corrosion resistance, is not easy to age, has long working life, good wear resistance, and can automatically compensate after wear to a certain extent. 4. Simple structure, easy to use and maintain, so that the sealing ring has a longer life. Seal ring damage will cause leakage, resulting in the waste of working media, pollution of the machine and the environment, and even cause mechanical operation failure and equipment personal accidents. Internal leakage will cause the volumetric efficiency of the hydraulic system to drop sharply, and the required working pressure can not be reached, or even the work can not be carried out. The tiny dust particles that invade the system can cause or exacerbate the wear of the friction pairs of the hydraulic components, further leading to leaks. Therefore, seals and sealing devices are an important part of hydraulic equipment. The reliability and service life of its work are an important indicator to measure the quality of the hydraulic system.
