Many seals are composed entirely or mainly of elastomer or plastic materials. Elastomer material; by adapting for shaft movement in the dynamic sealing environment, they provide sealing with the equivalent force applied against the hydrostatic forces formed in the film layer. In static sealing environments, their volumes remain constant and provide sealing with their shape-changing features.
Feature of elastomer material; determination of the sealing element temperature and fluid resistance is one of the most important parameters that affect the performance of the sealing element in the usage environment. FEKO seals provide the best performance of the sealing element with rubber formula designs suitable for the usage environment.
Sealing element in order to operate in desired performance, the choice of elastomer material must be proper for the usage environment. Incorrect selection of elastomer material causes huge problems. Therefore, when supplying the sealing element, ask help from our expert engineers in the products that are actually very similar in appearance but show great differences in function.
Click for the material selection table according to Heat and Fluid Resistance. Table1x (2)
Click for material selection table according to Rotation Speed and Shaft Diameter. Table 2
Each elastomer material has a usage temperature range determined by the base rubber in its formula. If sealing elements are used outside of this temperature range, leakage problem occurs as a result of changes in the physical and chemical properties of the elastomer material.
While determining the temperature value that will be the basis for the choice of elastomer material, the temperature of the fluid in the environment and the temperatures occurring under the sealing lip should be evaluated for dynamic sealing elements. Refer to Table 1 in the selection of elastomer material suitable for the fluid temperature.
In dynamic seals, the movement speed of the shaft and the friction heat provides a higher temperature than the fluid temperature value under the sealing lip. Refer to Table 2 for the selection of elastomer material according to the diameter and speed of the shaft.
The degree of interaction among elastomer material and the fluid depends on the chemical structure of the fluid and the ambient temperature. If an inappropriate elastomer material is selected, this material interacts with the fluid in the usage environment. As a result, physical and chemical changes take place.
Chemical structures of elastomer materials vary depending on the type of base rubber. In the same sealing environment, elastomer materials prepared from the same rubber undergo similar changes. Please refer to Table 1 for material selection.
Selecting elastomer material that is not suitable for the fluid in the environment causes the material to change physically or chemically. The effect of these changes on elastomer material is as follows:
- Diffusion of the fluid into the elastomer material as a result of the interaction causes the wear resistance of the sealing member to decrease and its volume to increase, thus increasing the friction. This results in the wear of the sealing element in a short time. Volumetric changes in static seals are more acceptable.
- As a result of the interaction, the elastomer material hardens and shrinks in volume as a result of the plastifyants in the fluid elastomer material being extracted into the fluid medium. Volumetric shrinkage increases the risk of leakage in dynamic and static sealing applications. In dynamic applications, hardening of the elastomer material affects the dynamic performance of the elastomer, thereby reducing the life of the sealing element.
- The chemical interaction of the elastomer material of the sealing element with the medium in the medium causes permanent deterioration in the structure of the elastomer material. The sealing element leaks in proportion to the change in the structure of the material or its life is shortened.