GB746428A - Improvements in combined liquid and contact seals between a rotating shaft and a casing wall - Google Patents

Abstract

746,428. Stuffing-box substitutes. SOC. ALSACIENNE DE CONSTRUCTIONS MECANIQUES. March 30, 1954 [Sept. 15, 1953], No. 9311/54. Class 122(5) A shaft 1 is sealed where it passes through a casing wall 2 by a combined liquid and contact seal comprising an impeller 5 keyed to the shaft and housed in an annular space 13 in the casing 3 to form therewith a passage of U-shaped cross-section fillable to a certain level with liquid 14 and an elastic ring 10 housed with substantial axial and radial clearance in a chamber 9 within the impeller to which the ring is rotatively fixed with freedom to expand radially, the ring being adapted when at rest to fit tightly around a sleeve 11 which surrounds the shaft 1 with clearance and is secured in fluid-tight manner to the casing wall 2. The ring 10 is connected to the impeller by pins 12 secured to the latter and freely engaged in notches 12a in the periphery of the ring. At rest and at low shaft speeds the shaft is sealed by the elastic ring 10. At a predetermined speed and above the ring is deformed by centrifugal force to break contact with the sleeve 11 and the shaft is sealed by the liquid 14 which is thrown outwardly against the periphery of the chamber 13 to form a liquid seal. The ring 10 is pressed axially into engagement with the wall 5a or 5b of the chamber 9 according to whether the pressure inside the casing is greater or less than that outside.