a rotary seal assembly for a rotary support table for use in drilling systems and the like to provide pressurized fluid to a rotary slip assembly disposed within the rotary support table is provided . the rotary seal assembly is designed to be coupled to an existing rotary support table which is used to rotate a drill string , and includes a powered slip that is powered into an engaged position to securely engage a pipe segment , for example , a casing segment . the rotary seal assembly generally comprises a ribbon of expandable material having an outer surface in fluid communication with a source of pressurized fluid , and an inner surface cooperative with a rotary housing , the rotary seal having a plurality of openings capable of communicating fluid between said outer and inner surfaces , wherein the outer seal surface has a surface area greater than the inner surface such that when the pressurized fluid is conducted to the outer surface of the seal a differential pressure between the outer and inner surfaces is created such that the inner surface of the seal is expanded to engage the rotary housing and form an annular fluid duct providing fluid communication between the pressurized fluid source and the rotary housing . a method of operating a rotary table and powered slip assembly utilizing the rotary slip assembly of the current invention is also provided .