To avoid leaks to the outside and achieve a correct static seal in flanged joints, the packaging must be correctly selected. The variables indicated to choose this element must be: pressure, temperature and process fluid.
In selecting a soft gasket special care must be taken with the service temperature, common elastomers work well up to 121°C, aramid fibers with a nitrile binder up to 204°C, sheets with carbon fibers up to 343°C, sheets graphite up to 454°C and PTFE up to 232°C. It is important not to exceed the design conditions of soft packaging; high temperatures generate fiber deterioration, crystallization and degradation of static sealing materials.
In standard spiral packaging, there are 2 models, WR and WRI, the difference between these two models is the internal ring that the WRI model has. It is recommended to use WRI gaskets at high pressures and/or large diameters, it is also necessary to use the inner ring when the filling of the winding (spiral sealing area) is PTFE. One of the main functions of the inner ring in a spiral gasket is to provide additional support to the radial force to prevent the buckling effect caused by large installation torques; The internal ring distributes the loads better, preventing the winding from unwrapping and being transported through the pipe, which could affect sensitive equipment within the line.