First of all, we need to know that whether it is silicone or rubber, soft gum products have to rely on extrusion deformation to produce sealing effect, so when the pressure is greater than the pressure of the sealing medium, the sealing effect will be produced The fundamental reason is the permanent deformation of the silicone rubber ring under the high pressure of the working environment and the bite caused by being squeezed into the gap, so this is the main core factor, and on the basis of this factor, there are several inevitable factors.
First: the working pressure leads to the deformation and failure of silicone rubber ring; pressure extrusion is the main cause of permanent deformation of silicone rubber ring, and the pressure of medium has a greater impact on the deformation of silicone rubber ring, which is also the most common deformation of silicone rubber ring in all industries. With the development of modern hydraulic equipment, the pressure of hydraulic medium is increasing, and the silicone rubber ring has been here for a long time In a high-pressure environment, permanent deformation will be caused, which is irreversible. Therefore, different materials should be selected according to different working pressures, such as silica gel or rubber materials with relative pressure resistance, wear resistance and temperature resistance. Correspondingly, in order to cope with higher working pressure, the hardness of silicone rubber ring made of pressure resistant materials will also increase.
Second: temperature causes failure; temperature is very important for the relaxation of silicone rubber ring. No matter what kind of material, it will accelerate its aging speed at high temperature. When the temperature in the environment is higher, the deformation of air compression will be greater. When the deformation of the product exceeds 40%, the silicone rubber ring will slowly lose its elastic capacity, causing leakage. When installing silicone rubber There will be initial stress when installing the silicone rubber ring, which will slowly disappear due to the long time relaxation of the silicone rubber ring and the gradual decrease of the temperature. In some cases, it may disappear with the sharp drop of the temperature. Even if the silicone rubber product material is resistant to high and low temperature, compared with the stress at 20 ℃, it will not be greater than 25%. Therefore, the initial stress should be set when installing the silicone rubber ring Stress, to fully consider the temperature factor in the working environment.
Third: the factors of compression and stretching; because the formula of silicone rubber rings is different, the compression and stretching strength of silicone rubber rings produced by different enterprises are also different. Under the condition of long-term compression, the product will produce the phenomenon of compression stress relaxation, which will gradually expand with time. The longer the time is, the smaller the amount of compression and tension will be, so that the lack of elasticity will lead to leakage. The most direct way to change is to increase the cross-section size of the product, but it will also lead to the increase of the structure of the product.
So in the early use process should be done in the selection of silicone rubber, its friction coefficient must be low, lubrication must be in place, it is the contact surface must be smooth, can not be rough, there are stains. In the process of installation, the coaxiality of installation should be ensured, and the eccentricity should not be too large. At the same time, the rationality of sealing system should be ensured, and the size error should not be too large. Today, I'll explain to you. I believe you have a new understanding of the main reasons for the failure of the sealing performance of the silicone rubber ring. If you have any problems, you can call to understand us.
