STASSKOL has always relied on its own materials to achieve good tribological performance, i.e. low heat generation and low wear. Based on the know-how in the development of high-performance polymers built up over many decades, new recipes were developed for the SDF Series and tested on the in-house tribometer. The focus was on minimizing friction and wear to maximize the service life of the SDF Series. In addition to the high wear resistance, special attention was paid to properties such as E-modulus, tensile strength and elongation at break to avoid damage to the sealing rings under heavy mechanical loads as far as possible. Product contamination must be avoided, especially in the food sector. To achieve this reliably, the sealing ring of the SDF Series can also be made of a special material that enables particles to be detected efficiently. The development of this recipe is based on experiments in which tiny samples were introduced into chocolate and identified using X-ray detection. Even the smallest samples could be reliably detected in the product (see Figure 2).

In this way, the customer can be offered a sealing system which, in addition to an efficient sealing effect, combines maximum wear resistance with high mechanical stability, and whose detectability of the central sealing material guarantees a high level of process reliability, especially in the food sector.

To confirm this in practice, the most promising material combinations were tested in the form of prototypes of the SDF Series on a shaft sealing test rig under process-related operating conditions. With variations in pressure and speed, wear and leakage rates as well as the temperature at the sealing surface were recorded (Figure 3). The test results showed that the material SK933 is the ideal solution for the sealing rings, as it offers the best tribological and thermal performance with high strength.