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Photo credit: istockphoto - © curraheeshutter
Hydraulic systems in marine environments require a complex combination of specialized seals. Understanding the different materials and styles is critical to a safe, successful design.
Hydraulic applications are challenging to seal. Not only must the hydraulic seals prevent leakage of fluid from the cylinder, but they must also withstand high pressures, extreme temperatures and transverse forces within the cylinder. The function of hydraulic seals goes far beyond preventing fluid leakage. Hydraulic systems are not sealed with one seal, rather a complex combination of specialized seals. Hydraulic rod seals prevent leakage of fluid from within the cylinder to the outside, while hydraulic piston seals prevent fluid from flowing across the cylinder head. This allows pressure build-up on one side of the piston, making the cylinder extend or retract. Wear rings guide the piston and piston rod within the hydraulic cylinder, absorbing transverse forces and preventing metal-to-metal contact. Scrapers—also called wipers—scrape dirt, foreign particles, chips or moisture from the piston rods as they retract into the cylinder, preventing contamination.
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