Sealing applications that involve steam require a careful consideration of the gasket material that will be chosen. Steam service applications can be tough on elastomeric materials, given the high heat and pressures involved. In this blog, we look at some of the challenges associated with gaskets and seals for steam and superheated steam service, as well as the materials that have shown themselves to work well in this type of application.
About steam and superheated steam
Steam is water in the gaseous state. It is usually formed by boiling water. Once water reaches its boiling point (100°C, 212°F) it is vapourized and turned into saturated steam. When saturated steam is heated above the boiling point, dry steam is created and all traces of moisture are erased. This is called superheated steam. Depending upon the pressure involved, superheated steam can have a temperature well in excess of 100°C (212°F).
Steam and superheated steam are often encountered in boilers, steam generators, turbines, heat exchangers, process equipment, etc. In these applications, it is important to select a gasket material which can withstand the high service temperatures and pressures without breaking down. At CRG, we manufacture gaskets and seals for steam service from elastomeric materials that are especially formulated to withstand these severe service conditions.
CRG gaskets and seals for steam and superheated steam service
CRG gaskets and seals for steam and superheated steam service are manufactured from a compressed sheet rubber (Teadit NA-1122) that possesses superior thermal stability in thermal cycling applications. This material is an excellent choice for gaskets and seals designed to service both saturated and superheated steam applications. It is also a suitable material for producing gaskets and seals for applications involving petroleum derivates, ethanol, chemical products and general services.
NA-1122 sheet is produced from a combination of inorganic fibers and special fillers, which are then bonded with nitrile rubber (NBR). The sheet is manufactured through a hot calendar process and is also available in a wire-reinforced style.
Service limits for CRG gaskets and seals made from NA-1122 sheet include: continuous temperature up to 430°C (806°F); peak temperature of 550°C (1022°F); continuous pressure of 1480 psi; and peak pressure of 2177 psi. In sealability tests, NA-1122 sheet reached its target of work above 426°C (800°F) and 1480 psi without leakage. In thermal cycling tests, NA-1122 sheet was submitted to numerous thermal cycles (more than 10 daily cycles) with a seating stress of 5800 psi, and temperature increases up to 426°C (800° F). Both laboratory and field tests have confirmed the higher performance of NA-1122 compressed sheet.
CRG precision-cuts gaskets and seals in a variety of sizes and shapes for steam and superheated steam service. These gaskets are produced using the latest CNC production techniques, ensuring precise dimensioning and tight tolerancing.
For further information on the gaskets and seals for steam and superheated steam service that CRG can supply, please contact our sales department at crg@canadarubbergroup.com.