XT200, product of 2 years of Research and Development, is an extrusion resistant rod seal that is designed and developed for challenging applications that require both extrusion resistance and low leakage.

In many fluid power applications, hydraulic rod seals are exposed to high pressures, which can exceed 250 bar, or even higher peak pressures due to operational conditions. Customer expectations from a rod seal are increasing with a target of producing cylinders that can handle higher pressures, together with low leakage, without compromising from friction and service life. From excavators to cranes, platform-lifts to injection-molding-machines, rod seals that can provide extrusion resistance together with longer service life, low leakage are required.

In order to achieve this ambitious goal, a Kastas team of experienced engineers with expertise in design, material sciences and testing started to work on XT200 from scratch two years ago. XT200, as they named this high-performance rod seal, should have a design that meets the demands for advanced leakage, extrusion and friction behavior and at the same time should be produced from a material characterized by the required compression set values, temperature range and extrusion behavior. The initial project target was to design and develop a rod seal that improved the leakage and extrusion performance of the existing rod seals offered by Kastas and the key competitors by 15-25%.

Thus, in the design phase, XT200 development team provided several designs that would meet this aim. Using advanced Finite Element Analysis software, all alternative designs were simulated in a wide range of operating conditions that would be likely encountered in practice. The design that exhibited the best performance in terms of extrusion, leakage and friction was selected for further refinement, aiming to optimize friction, sealing edge and static tightness.

Parallel to this initiative, members of the Design and Tool Department worked on the most efficient and reliable tool design to ensure a smooth production of the new design along with long-term production efficiency. Following the development of several prototypes, 11 months after the project started, the first test sample of XT200 was produced. It was subjected to a yearlong intensive dynamic and static testing, conducted on test rigs. These tests aimed to simulate real life applications, while also determining the operational limits of the seal. After a total of 1800 km long testing in our R&D Test Center, which resulted in several design improvements, the final version of XT200 was ready for field tests. For the next four months, XT200 was tested against two competitor rod seals internally, as well as externally in the field, aiming to obtain reliable leakage and extrusion values, as well as preload losses. While a seal performance is highly dependent on the design, choice of material is critical for both performance and service life. Material properties such as temperature range, compression set, and hydrolysis resistance, along with many other highly influential mechanical properties, must be carefully selected, in addition to chemical structure and media compatibility. All these factors should comply with the seal performance targets in relevant applications, as well as outperform in bench and field tests those already available in the market.



New generation PU9401 is the thermoplastic polyurethane chosen for standard XT200 production, owing to its superior mechanical properties necessary for optimal extrusion and abrasion behavior. Moreover, it has compression set values below the industry benchmark, thus ensuring the desired preload and leakage performance. Moreover, PU9401 operates in a wide temperature range, which makes it suitable for use in all targeted applications.


The Key XT200 Design Features:
► Special Lip Geometry
► Optimized Sealing Edge
► Innovative Grooved Ring Design
► Reduced Contact Surface
► Innovative Undercut Profile
► Increased Extrusion Resistance
► Excellent Static and Dynamic Tightness

Key Material Features:
► Advanced Mechanical Properties
► Wide Temperature Range
► Low Compression Set
► Abrasion and Extrusion Resistance
 

Innovative design for enhanced sealing performance

K17X High Performance Piston Seal is the new addition to the Kastas’ O-ring energized piston seal range that offers additional advantages compared to the standard K17 Piston Seal in demanding applications. K17X retains the low friction and low static leakage benefits of the standard design, while its special profile ensures increased extrusion resistance and minimized blow-by risk.



Standard K17 is a successful piston seal with good sealing, friction and abrasion behavior, which proved its superior performance in many applications. “However,” as explained by Ozan Devlen, R&D Manager of Kastas Sealing Technologies, “customers are demanding increased extrusion resistance from PTFE piston seals in many challenging applications to work safely at higher pressures and larger gap clearances. Another issue in large-diameter double-acting systems is the blow-by. Piston seals are expected to react instantly to pressure shifts in reverse movement. Therefore, we have developed K17X by modifying the current K17 design and adding innovative design features to fulfill customer demands.”

K17X has inclined lateral profile flanks that taper the seal profile towards the sealing surface. Additionally, the chamfers are extended to the seal surface. This special seal profile allows the seal to tilt and move smoothly in the groove by enabling pressurized media to energize the piston seal effectively. This innovative design feature increases system safety by minimizing blow-by risk in double-acting cylinders, while significantly enhancing the extrusion resistance at higher pressures and larger gap clearances.