The most important function of a mechanical seal is fluid containment: to prevent leakage. By design, fluid film is created between sliding surfaces to reduce friction and dynamic torque, but the resulting gap increases potential for leakage. In contrast, narrower gap reduces leakage while torque increases.
Therefore, it had not been feasible to offer a mechanical seal with both low torque and superior sealing capabilities.
With introduction of surface texturing technology, EKK is the first to bring these two contraries together.
Utilizing surface texturing technology, EKK is capable of offering optimized solutions for various operating conditions and functional requirements. In any cases, EKK achieves over 90% reduction in torque, compared to conventional mechanical seals, while ensuring superior sealing performance. For conventional seals, maximum speed approaching 50m/s could be attained without significant leakage. However, surface textured seals may be applied beyond this speed limit with uncompromised fluid sealing.
A textured surface is an uneven, micro structure that is processed to the sliding component.
During rotation, fluid is drawn into the textured surface to generate positive pressures, promoting formation of fluid film and separation of the sliding surfaces. As a result, friction is reduced by 90% or more, compared to the conventional sliding surface.
Furthermore, an optimized texture can also generate negative pressures, preventing fluid leaking passed the sliding surfaces. This achieves leakage reduction of over 90%.
EKK is capable of optimizing the textured surface design for various functional requirements. By processing different, independent textures to the same sliding surface, multi-functional characterization can be realized.
EKK employs various numerical analysis and measuring techniques to design textured surfaces.
Illustrations below compare numerical analysis of the pressure profile and phenomenon observed between actual sliding surfaces.
As anticipated from the pressure analysis, fluid (droplets applied for observation) at the atmospheric side is drawn to the fluid side due to negative pressure generation between the sliding surfaces (i.e. pumping effect).
The graph below is an example of test results comparing coefficients of friction for conventional and textured sliding surfaces. Surface texturing is found to reduce friction up to 98%. At the same time, numerical analysis is validated with its close correlation to actual test data.