Cylindrical ring made of anti-spark, material, normally bronze or graphite, installed in the stationary seal flange so as to minimize the space (gap) between the inner diameter of the flange itself and the rotating shaft sleeve.
The bushing’s function is to channel the seal’s physiological leakage towards the flange’s drainage connection and to prevent contact between the seal flange and the shaft sleeve in case of abnormal and unforeseen radial movements of the machine shaft.