A hydraulic seal is a relatively soft, non-metallic

ring Ring may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell :(hence) to initiate a telephone connection Arts, entertainment and media Film and ...

, captured in a

groove Groove or Grooves may refer to: Music * Groove (music) * Groove (drumming) * The Groove (band), an Australian rock/pop band of the 1960s * The Groove (Sirius XM), a US radio station * Groove 101.7FM, a former Perth, Australia, radio station * ...

or fixed in a combination of rings, forming a seal assembly, to block or separate

fluid In physics, a fluid is a liquid, gas, or other material that continuously deforms (''flows'') under an applied shear stress, or external force. They have zero shear modulus, or, in simpler terms, are substances which cannot resist any shear ...

in reciprocating motion applications. Hydraulic seals are vital in

machinery A machine is a physical system using power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromolecule ...

. Their use is critical in providing a way for fluid power to be converted to linear motion.

Materials

Hydraulic seals can be made from a variety of materials such as

polyurethane Polyurethane (; often abbreviated PUR and PU) refers to a class of polymers composed of organic chemistry, organic units joined by carbamate (urethane) links. In contrast to other common polymers such as polyethylene and polystyrene, polyurethan ...

rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

PTFE Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemour ...

. The type of material is determined by the specific operating conditions or limits due to fluid type,

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...

, fluid chemical compatibility or

temperature Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied o ...

Static

static Static may refer to: Places *Static Nunatak, a nunatak in Antarctica United States * Static, Kentucky and Tennessee *Static Peak, a mountain in Wyoming **Static Peak Divide, a mountain pass near the peak Science and technology Physics *Static el ...

hydraulic seal is located in a groove and sees no movement - only sealing within its confined space, acting like a

gasket Some seals and gaskets A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression. It is a deformable material that is used to c ...

. To achieve this the gasket should be under pressure. The pressure is applied by tightening of the bolts.

Dynamic

A type of

dynamic Dynamics (from Greek δυναμικός ''dynamikos'' "powerful", from δύναμις ''dynamis'' "power") or dynamic may refer to: Physics and engineering * Dynamics (mechanics) ** Aerodynamics, the study of the motion of air ** Analytical dynam ...

hydraulic seal called a rod seal is exposed to movement on its inner diameter along the shaft or rod of a hydraulic cylinder. Hydraulic Piston seals prevent fluid from crossing the area of the piston head. Rod seals ensure that fluid does not leak from the cylinder and adequate pressure is maintained. Wiper seals are installed to prevent contamination from entering the hydraulic system. A rod seal prevents leakage of hydraulic fluid to the outside of the sealing system. Additionally, rod seals help contribute, in combination with a wiper seal, to preventing contamination of the environment. A type of dynamic hydraulic seal called a

piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tig ...

seal is exposed to movement on its outer diameter along the tube or bore of a hydraulic cylinder. Different Piston Seal profiles offer distinct advantages depending on the sealing application. Temperature, Pressure, Stroke Speed and other environmental considerations would lead users to different profiles and materials.

References

{{DEFAULTSORT:Seal, Hydraulic Hydraulics