Utility temperature is an important factor affecting rubber O-ring, and high temperature will accelerate the aging of rubber data.The higher the operating temperature, the greater the permanent deformation of O - ring contraction.When the permanent deformation is greater than 40%, the O-ring loses its sealing ability and leakage occurs.The initial stress value formed in the rubber data of the O-ring due to compression deformation will gradually decrease and even dissipate with the action of the O-ring relaxation process and temperature drop.

The initial contraction of an O-ring operating at sub-zero temperatures may be reduced or completely dissipated by a sharp drop in temperature.O-ring is usually selected to try to choose a large section of O-ring.For the same clearance, the volume of O-ring pressed into the clearance shall be less than the maximum allowable value of O-ring pressed into the clearance.Silica gel sealing ring has an open porous structure, can adsorb many substances, is a good desiccant, adsorbent and catalyst carrier.The adsorption of silica gel is mainly physical adsorption, can be regenerated and repeated use.In the alkali metal silicate (such as sodium silicate) solution add acid, make it acidic, and then add a certain amount of electrolyte for stirring, that is, the formation of silicate gel;Or in the more concentrated sodium silicate solution added acid or ammonium salt can also form silicate gel.Under the condition of -50~-60℃, the rubber material which is not resistant to low temperature will completely lose the initial stress.Even for low-temperature resistant rubber, the initial stress at this time will not be greater than 25% of the initial stress at 20℃.This is because the initial amount of contraction of the O-ring depends on the linear expansion coefficient.Therefore, when selecting the initial amount of shrinkage, it is necessary to ensure that there is sufficient sealing ability after the stress drop due to the relaxation process and temperature drop.For O-rings working at sub-zero temperature, special attention should be paid to the recovery index and deformation index of rubber data.

To sum up, in the design, we should try our best to ensure that the O-ring exists a suitable working temperature, or choose the O-ring data resistant to high and low temperature, in order to extend the service life.