Radial shaft seal for screw centrifuge for solid-liq. mixt. sepn. - comprises helical sealing element of PTFE pressed in operating position by centrifugal force, for sealing rotating hollow shafts annular gap

摘要

The seal is intended, in partic. for screw centrifuges used for sepn. of solid-liq. mixts. It seals the annular gap (27) between two hollow shafts rotating at differeing speeds. The seal comprises sealing rings (28) located and radially guided in external groove(s) (29) of the inner hollow shaft. The outer contour of the sealing rings is pressed against the inner wall of the concentric outer shaft (26) by the effect of a centrifugal force produced during operation of the centrifuge. The sealing rings (28) are pref. helically wound elastic sealing elements comprising part(s). They are located in corresp. shaped grooves. The handling of the grooves and sealing elements is pref. so the axial delivery is directed towards the prodn. space of the centrifuge. The circumferential angle of the helical sealing elements is greater than 360 deg. The height to width ratio of the cross-section of the sealing elements is pref. at least 1.5:1. The material has a low coefft. of friction and contains e.g. PTFE (polytetrafluoroethylene). USE/ADVANTAGE - Used in mfr. of screw centrifuges. The seal has a simple construction and a long working life.