Type 28ST

Non contacting Gas Seal for Steam Turbines

Type 28ST combines proven rotating groove technology and high temperature secondary seals to reduce steam leakage by nearly two orders of magnitude, as compared to traditional sealing devices, such as segmented carbon rings and labyrinths. This steam lubricated, end face cartridge seal reacts instantaneously and automatically to maintain a safe face gap despite sudden changes in operating conditions. A stable seal face gap, typically 0.0001" to 0.0002"/0.0025mm to 0.0051mm, is the result of specially designed rotating grooves, which pump steam radially inward into a nongrooved portion of the seal known as the "sealing dam."