Chemical abrasive handling: Steam leakage reduction with carbon rings

摘要

Operators of general purpose steam turbines know all about the problems of conventional carbon ring seals. This article assesses alternatives for the reduction of steam leakage and ease of installation, including mechanical seals and the Sentinel Floating Brush Seal. Carbon rings remain the standard in general purpose steam turbine sealing, despite well-known shortcomings. Chief among those shortcomings is wear at the rings' inner bore, gradually increasing shaft clearance and steam leakage and leading to regular replacement - as frequently as four times per year. Carbon rings are simple to install and the replacement cost for a complete set is less than $1,000, so the cost of maintaining sealing with carbon rings appears to be relatively modest. However, there are further costs associated with the wear and potential breakage of carbon rings, including higher water costs due to steam losses and degraded bearing performance due to oil contamination and higher operating temperatures.