?Four important points rubber O-ring

??1 / rubber O-ring temperature

??This parameter is a rubber O-ring during use a very important parameter. In some cases, it can directly determine the effect of seals and seal life. The use of long-term use temperature must be clear how much, how much extreme temperatures, depending on the corresponding selection of material performance requirements. At the same time, we should also recognize that, for the same seal material maximum temperature and minimum temperature accurate description is more difficult, because it is the result of the combined effects of a number of factors. Just clear the basic temperature performance requirements and the number of seals using temperature materials, generally no problem.

??2 / rubber O-ring friction

??Factors affecting the rubber o-rings had a lot of friction, mainly rubber O-rings and the sealing material and surface roughness of the surface, the use of pressure, medium and temperature.

??Surface treatment 3 / rubber O-ring

??Affect the quality of the surface treatment of a rubber O-ring life is very large. Surface roughness RA is the arithmetic mean of deviation from the centerline of the surface shape of the absolute value.

??4 / rubber O-ring pressure

??Stress is the hardness of rubber O-ring to select key indicators. The greater the pressure should be selected higher hardness high seal. Similarly, if the pressure should try to use a relatively small hardness is relatively small, so that the sealing performance will be better. For example, under normal circumstances, nitrile rubber, fluorine rubber, EPDM and silicone usual hardness NBR70, FKM75 / VITON75, DEPDM70 and SIL70; if the pressure is big, it should be 80, 85 or 90 degrees of hardness. At the same time, high and low pressure cycles and changes in the length of the pressure on the o-ring extrusion and other damage to health has a significant impact. And the higher the pressure will lead to the sealing performance of other adverse circumstances, such as a piston and cylinder gap between the temperature and speed.

??Vacuum rubber imports o-ring

??It has very important applications in the vacuum appliance and aerospace. This ring structure is simple, inexpensive, but if the choice or improper use, especially due to the loss in aerospace applications will be a very, very large. In the vacuum seal, the sealing medium is a gas, and the pressure are generally small, usually less than a standard atmosphere; to compare easily with the liquid leaking from the gap between the contact surface, so we must pay great attention to the contact parts of the surface roughness. And to use low permeability and low compression deformable material, generally fluorine rubber FKM (VITON) Nitrile rubber NBR contrast is better, therefore, suggested the use of fluorine rubber O-ring seal for vacuum. In addition, the design and use should note the following:

??1 / To reduce the chance of leaks, try to use vacuum grease used together;

??2 / To increase the contact area and extend the diffusion time through the seal, the space-installation groove to fill up with almost 100% of the volume of the o-ring after deformation;

??3 / contrast hydrostatic seals, vacuum-sealed mounting groove roughness of each surface to be more stringent, the percentage of the reach of greater than 50%;

??Cross section 4 / o-ring compression deformation of about 30%.