O-ring Resistance To Medium Aging, Deformation And Relaxation Performance
O-ring is the most commonly used seal in a seal. 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 should try to use the new national standard, diameter 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, the O-ring is an 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, cover, etc. O-ring with axial compression easier to assemble and ensure the sealing performance. In addition, the national standard in the trench size standards have been significantly behind, such as the national standard by the internal pressure of the O-ring groove diameter equal to the O-ring diameter, and PARKER flange O-ring groove diameter Less than O-ring outer diameter. Design should be appropriate reference to foreign standards.
O-ring O-ring is a circular rubber ring section, because of its cross-section of the O-type, it is called O-ring, also known as O-ring.
O-rings are suitable for use in a variety of mechanical equipment, in the specified temperature, pressure, and different liquid and gas medium, in the static or moving state from the sealing effect. In the machine tools, ships, automobiles, aerospace equipment, metallurgical machinery, chemical machinery, construction machinery, construction machinery, mining machinery, petroleum machinery, plastic machinery, agricultural machinery, and various instruments, a large number of applications of various types of seals element. O-rings are mainly used for static and reciprocating seals. For rotary motion seals, only for low speed rotary seals. O-ring is generally installed in the outer or inner circle on the rectangular cross-section of the seal from the role. O-ring in the oil, acid, grinding, chemical erosion and other environments still play a good seal, shock absorption. Therefore, O-ring is the hydraulic and pneumatic transmission system used in the most extensive seal.
At present, the quality of rubber O-ring detection, the majority of the use of caliper within the measurement, diameter and cross-section, the measurement error. Because the O-ring is a flexible material, the measuring force will cause it to not be ignored deformation, this measurement method is unable to meet the mechanical seal accessories precision requirements. The use of O-ring finished products directly determine the tensile, resistance to media aging, deformation and relaxation performance, integrated control of the production process and O-ring material of the material, the use of O-ring finished product quality control, Stability; and geometric measurement with electronic computer control or "screen dialogue" size and cross-section automatic measuring instrument.