Views: 0 Author: Site Editor Publish Time: 2023-06-09 Origin: Site
A gasket is a mechanical seal that fills the space between two or more mating surfaces,usually to prevent leakage from or into the connected objects when under pressure.It is a deformable material used to form a static seal and maintain that seal under the various operating conditions of a mechanical assembly.Gaskets allow "less than perfect" mating surfaces on machine parts to fill in irregularities.Gaskets are usually cut from sheet metal.Given the potential cost and safety hazard of a gasket failure or leak, selecting the correct gasket material for the application is critical.Gaskets for certain applications, such as high pressure steam systems, may contain asbestos.However, due to the health hazards associated with asbestos exposure, non-asbestos gasket materials are used where feasible.It is generally desirable that the gasket be made of a material that yields to some extent so that it can deform and tightly fill the space it is designed for, including any slight irregularities.Some types of gaskets require the sealant to be applied directly to the surface of the gasket to work properly.
Some (pipe) gaskets are made entirely of metal, relying on the sealing faces to achieve the seal; utilizing the spring properties of the metal itself (up to but not exceeding the yield strength σy of the material).This is typical of some "Ring Joints" (RTJ) or some other metal gasket systems.These fittings are known as R-con and E-con compression fittings. Some gaskets are dispensed and cured in place. form-in-place gaskets.
Gaskets are usually made of flat materials such as paper, rubber, silicone, metal, cork, felt, neoprene, nitrile rubber, fiberglass,polytetrafluoroethylene (also known as PTFE or Teflon), or plastic polymers (such as polychlorotrifluoroethylene).In industrial applications of compressed fiber gasket materials, one of the more desirable properties of an effective gasket is the ability to withstand high compressive loads. Most industrial gasket applications involve bolts applying pressure to the 14 MPa (2000 psi) range or higher. In general, there are several commonplaces that can improve gasket performance.One of the more tried and tested ones is: "The more compressive load you put on a gasket, the longer it will last".
There are several ways to measure the ability of a gasket material to withstand compressive loads.The "hot stress test" is probably the most accepted of these tests.Most gasket material manufacturers will provide or publish the results of these tests.
Gaskets are available in many different designs depending on industrial use, budget, chemical exposure and physical parameters:
Sheet gasket.Gaskets can be produced by stamping the desired shape from a flat sheet of thin material, resulting in sheet gaskets. Sheet gaskets are fast and inexpensive to produce and can be produced from a variety of materials, including fibrous materials and matte graphite (and, in the past, compressed asbestos).These gaskets can meet various chemical requirements depending on the inertness of the materials used.Asbestos-free gaskets are durable and come in a variety of materials with a thick texture. Examples of materials include mineral rubber, carbon rubber or synthetic rubber such as EPDM, Nitrile, Neoprene, Natural Rubber, SBR Block Rubber-each with unique properties for different applications.Applications using sheet gaskets involve acids, corrosive chemicals, steam, or mild corrosives.Flexibility and good recovery prevent breakage when installing sheet spacers.