Experience With API Plan 53b Pressurized Dual Seal Systems
Plan 53B is one of the newest API seal flush plans. It first appeared in the second edition of API 682. This case history is based on experience on a large project in China. This petrochemical complex is the first that the authors are aware of to apply this seal flush plan extensively (670 pumps with Plan 53B). This plan allows application of pressurized dual seals in plants with no nitrogen utility or at pressures above that of the nitrogen utility.
Jones, Roger (2010). Experience With API Plan 53b Pressurized Dual Seal Systems. Texas A&M University. Turbomachinery Laboratories. Available electronically from