Hydraulic seals manage the movement of fluid in devices that utilize reciprocating motion. They are a vital component of hydraulic cylinders, which have widespread applications in heavy-duty machinery such as bulldozers, cranes, excavators, asphalt pavers, forklifts, tractors, and other heavy equipment used in construction and agriculture. Hydraulic seals play a crucial role in the conversion of fluid power to linear motion.
Types
Static hydraulic seals are found in grooves and experience little to no movement. Their role is to seal, much like a gasket. When a static hydraulic seal is compressed, horizontal expansion occurs to relieve the pressure. It is therefore imperative to check that the groove is wider than the seal to prevent over-compression.
Materials
The material used to make a hydraulic seal depends on the operating environment, pressure, temperature and the type and chemical properties of the fluid. Rubber, polyurethane, and polytetrafluoroethylene (PTFE) are the most commonly used.
Dynamic hydraulic seals, on the other hand, experience some degree of movement and come in several varieties. Rod seals, for example, experience movement along the rod or shaft or a hydraulic cylinder to prevent leaking of pressurized fluid and are arguably the most important seal on any piece of hydraulic equipment Unidirectional rod seals function to seal dynamic pressure from one side. Buffer seals, for example, help a system’s primary rod seal to absorb pressure spikes. Bidirectional rod seals, such as some piston seals, manage pressure from both sides to ensure stability and prevent damage. For most applications, nonsymmetrical piston seals, in which the outer diameter lip differs in shape from the inner diameter lip, provide better performance and stability than symmetrical seals.
It may not be readily apparent, but hydraulic seals play a significant role in machinery. These seals help convert fluid power to linear motion by confining and containing fluid in applications with reciprocating motion. Most mechanisms with repetitive up-and-down or back-and-forth motions need hydraulic seals.
What are hydraulic seals made of?
Because hydraulic seals must form a liquid-proof seal, they are usually made out of a soft substance such as polyurethane, rubber, or polytetrafluoroethylene (PTFE), better known by its trademarked name, “Teflon.” Teflon is ideal for hydraulic seals since it can withstand temperatures up to 500°F, is chemically resistant, and is highly non-reactive. Teflon also has a low coefficient of friction which reduces wear on the product and bearing surfaces, extending the life of both products. Furthermore, Teflon complies with FDA and 3A standards, allowing it to come into direct contact with food. If have any Hydraulic Cylinder Repair needs, we always come in handy.
