O-ring Easy To Assemble And Ensure Sealing Performance
O-rings are the most commonly used seals in seals. However, due to the selection, groove design, processing and assembly on the improper, often caused by oil spills, can be described as small pieces of bad events.
China's national standards on the O-ring size of the standard GB1235-76, GB3452.1-88 and GB3452.1-92, which GB1235-76 O-ring cross-section diameter (also known as diameter) has 1.9,2.4, 3.1,3.5,5.7, etc., O-ring with "diameter × diameter" marking method, commonly known as the old national standard; GB3452.1-82 and GB3452.1-92 basically the same, generally known as the new national standard, which provides Of the O-ring diameter of 1.8,2.65,3.55,5.3, the new national standard with international practice, O-ring with "diameter × diameter" marking method.
O-ring, the first choice should try to use the new national standard, the diameter of 2.65 and 3.55 use the most common in the outer diameter of more than 30 or so, the structure size allows the case, try to use the diameter 3.55 O-ring to achieve greater Of the amount of compression and contact area.
O-ring materials are mainly butyl nitrile rubber NBR and fluorine rubber FKM, fluorine rubber is more suitable for high temperature conditions.
In addition to the material, O-ring is a very important indicator of its hardness, generally used Shaw hardness to represent, ranging from 60 to 90 or so, the greater the value that the higher the hardness. In the same pressure, the higher the hardness, anti-extrusion (deformation or even tear) the stronger the ability. Therefore, you should use the higher hardness of the O-ring.
However, the market common O-rings are made of butyl cyanide rubber, Shore hardness is generally around 70, it is difficult to meet a considerable part of the working conditions.
O-ring groove design has the relevant national standards, the main split seal, axial static seal and radial static seal three. Flange, box cover, etc. O-ring with axial compression easier to assemble and ensure the sealing performance. In addition, China's national standard trench size standards have been significantly behind, such as the national standard by the internal pressure of the O-ring groove diameter is equal to the O-ring diameter, and PARKER flange connector O-ring groove diameter Less than O-ring outer diameter. Design should be appropriate reference to foreign standards.
O-rings can not use the surface sealant sealant, you can apply a small amount of butter on the O-ring so that it does not fall off. In the maintenance, should be based on the size of the groove to determine the O-ring specifications, not the thicker the better diameter.