A test method for outdoor imported O ring
1 appearance quality inspection:
The appearance of using visual method. General O type seal ring does not allow the existence of pores, cracks, impurities, bubbles; surface should be smooth and clean. The type and quality requirements of surface defects shall not exceed the limits specified in the national standard GB 3452.2-87, and shall be divided into N grade and S grade according to the requirements for appearance quality.
2) dimensional inspection
According to the specific requirements of its cross section, the size of the internal diameter measurement. According to the specifications of size, can be used to meet the requirements of precision vernier caliper, ruler or tape measure; measured by the mobile projection microscope, microscope optical instrument. Dimensions and tolerances shall be in accordance with the national standards or the corresponding requirements of the size, in accordance with the GB 3452.1-92 standards for hydraulic systems and components used in general and aerospace O type sealing ring size and tolerance.
3 physical and mechanical properties of finished products
According to the different requirements of the product can also be used for physical properties test. The O ring hardness, tensile strength, compression permanent deformation, tensile permanent deformation, heat aging and compression stress relaxation, resistance to liquid, density test according to the GB/T 5720-93 standard "seal test method" test.
4) packaging inspection of finished products
The marking, packing and storage of the finished product can be carried out according to the general provisions of the mark, packing, transportation and storage of the rubber sealing products according to the GB/T 5721-93 standard.
 
Two. To ensure the outdoor special imported O ring, long life of several factors
1) select the O ring compression
Static seal: A, the cylindrical surface seal, the amount of compression 10-15%; B, on the surface of the static seal, the amount of compression 20-30%.
Reciprocating seal, compression: 10-15%;
Rotary dynamic seal: O shaped ring diameter ratio of the shaft diameter of 3-5% (Joule effect), the outer diameter of the compressed 3-8%.
2 rubber O ring contact surface finish for the static seal is generally not less than 3.22-1.6 level, for the dynamic sealing ring groove contact surface is not less than 1.6-0.8 level, for high pressure should take higher finish.
3) extrusion phenomenon: when the high pressure gap is large, the product may be in fluid pressure seal gap. The design must pay attention to, pressure, clearance, hardness, O ring diameter of these factors; a lot of pressure or the gap is too large, should be considered to increase the PTFE ring on both sides.
4) the installation of O type ring or imported O ring
Eliminate the burr on the part of the inlet and outlet channel when the O ring is installed;
Using guide tools;
To prevent the distortion of the O shaped ring installed in the installation groove.
 
Three. Outdoor use imported O ring and Taiwan imported rubber ring in the process of improvement
In the pressure is particularly large, the O ring is not used alone, or with the ring to use, and easy to be damaged. Improvement measures: the replacement of material is PTFE (outer ring) + rubber (inner), the fact that PTFE in organic solvent under the environment of long-term use can still maintain good performance, while the rubber elastic, can play a better role in sealing