The key factor of rubber O-ring is the application temperature, high temperature will accelerate the aging of rubber material. The higher the operating temperature, the greater the permanent deformation of O-ring contraction. When the permanent deformation exceeds 40%, the O-ring loses its sealing, leading to leakage. Due to shrinkage deformation, the initial stress value formed in the O-ring rubber data will gradually land and subside with the impact of aerodynamic process and temperature landing of the O-ring.
Due to the dramatic drop in temperature, the original contraction of O-rings operating at sub-zero temperatures may be reduced or completely subsided. O Generally use sealing rings, try to choose a large section of O-ring. In the same case, the volume of the O-ring squeezed into the void should be lower than its maximum. Silicone sealing ring is made of porous material, can absorb various substances, is a good moisture-proof agent, absorbent and catalyst carrier. The adsorption of silica gel is usually physical adsorption and can be regenerated and reused. In the alkaline metal silicate (such as sodium silicate) solution to add acid, acidification, and then pour a certain amount of electrolyte mixed, made of silicate suspicious glue; Or adding acid or ammonium salt to concentrated sodium silicate solution can also produce silicate suspicious glue. In the case of -50~-60℃, the rubber material will lose the initial stress completely. Even the rubber material with low temperature resistance, the initial stress will not exceed 25% of the initial stress at 20℃. This is because the original tightening amount of the O-ring depends on the coefficient of expansion. Therefore, when selecting the original tightening amount, it is necessary to ensure that there is sufficient sealing capacity after the stress landing caused by the temperature landing in the stress landing process. For O-rings working at sub-zero temperature, special attention should be paid to the recovery index and deformation index of rubber materials.
Generally speaking, in the design, we should try to ensure that the O-ring has a suitable working temperature, or use high and low temperature O-ring materials to improve the service life. Silicone products with silicone as the main raw material are called silicone products. Silica gel is a porous porous substance of various sizes, made from silicone acid suspicious glue. It is a good moisture-proof agent with open porous material that can adsorb various substances, absorbent and catalyst carrier.
