Trelleborg Makes Step Change in High-Pressure Radial Shaft Seals with New Stefa Portfolio
Stefa high-pressure radial shaft seals (HPRSS) are engineered to enhance sealing performance in various conditions, including speed, chemical compatibility, and pressure, and compensate for shaft misalignment.
Developed in conjunction with customers using finite element analysis (FEA) and advanced Trelleborg test rigs, Stefa® seals provide smart, globally compliant solutions for various types of hydraulic motors and pumps. They are proven at pressures of up to 20 MPa and speeds of up to 17 meters per second (MPS).
High-pressure radial shaft seals are critical components in various markets for vehicles in the construction, mining and agricultural sectors, material handling processes including winches and presses, and industrial uses including gearboxes and engines, as well as numerous applications for the aerospace, automotive, marine and energy sectors.
Inderjeet Singh, Global Product Line Director, says: “Working closely with our customers and utilizing our own advanced manufacturing, R&D and testing facilities, we have delivered a step change in performance and durability with the enhanced Stefa® radial shaft sealing range.
“Equipment that requires high-pressure radial shaft seals is typically complex and high value, and any seal failure will be an expensive liability for the operator. Over several years, we have leveraged our advanced global in-house R&D capabilities to optimize geometries and materials to provide customer assurance in terms of performance and durability across a wide range of applications with differing requirements.”
The range includes the well-established HP20 series which utilizes a patented design geometry that self-balances under strong pressure with a metal retainer that prevents lip extrusion and dissipates heat, extending service life. Millions of the HP20 seals have been sold since its introduction in 2010. The HP20 is capable of operating at up to 20 MPa pressure and rotational speeds of up to 2 MPS.
The new HP20S is a high-quality, cost-efficient and long-lasting solution for high-torque, low-speed motors. It is proven at up to 15 MPa and speeds of 5 MPS with an energized spring lip that enables it to work without pressure. The HP20S excels even with reduced lubrication as pads and channels improve lip lubrication at start-up and higher shaft speeds to reduce wear.
Due to its flexible lip geometry energized by a stainless-steel spring, the SPS-HP20 excels where there is misalignment between shaft and bore. Its relatively simple design provides a cost-effective solution with superior performance in applications such as hydraulic motors driving a pulley, where there is side load in one direction with the potential to cause gradual deformation of the bearings. The SPS-HP20 features customizable design options in terms of materials and geometries for specific applications and is proven at pressures up to 15 MPa and speeds of 5 MPS.
The innovative SPV seal offers enhanced service life at high speeds and is optimized to manage pressure spikes and changes in direction. It is proven at rotational speeds of up to 17 MPS and pressure up to 0.5 MPa but can handle pressure spikes of up to 2.5 MPa, conditions typical in pumps, hydraulic motors and some gearboxes. It is available in a range of elastomer grades customizable for specific application needs, including premium hydrogenated nitrile butadiene rubber (HNBR) and fluoroelastomers (FKM) materials.
Finally the established TRP seal has been upgraded to offer exceptionally low friction in applications up to 0.5 MPA of pressure at up to 10 MPS speed. Its proprietary geometry effectively combines performance and manufacturing reliability with an additional dust lip providing enhanced protection to extend lifespan in polluted environments and improved lip contact to reduce friction and optimize sealing efficiency. The composition of TRP can be tailored for specific operating environments, including HNBR, nitrile (NBR) and FKM elastomer materials.
Singh adds: “Since the success of HP20, launched over a decade ago, we have substantially enhanced our Stefa® HPRSS range through a combination of our own cutting-edge global R&D and testing capabilities at locations including China, Italy, United States, India and Germany, while working closely with key global customers.
“Performance expectations for high pressure radial shaft seals are becoming ever-more challenging, with customers in recent years demanding solutions that work at even high speeds and accelerations. To meet the challenges, we have built advanced test rigs with wider capabilities in terms of operating parameters such as temperature, speed, torque and pressure, as well as pressure spikes and side loads. Trelleborg’s customer proximity has been critical to the successful innovations in our Stefa® portfolio, leveraging our materials expertise and design capabilities alongside deep collaboration with customers to provide optimized solutions.”
Register for the customer webinar on the new Stefa® range here.
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