SEALING DEVICE BETWEEN MOVABLE PARTS

摘要

The sealing device is intended for sealing in one direction between the co-operating surface of a cylindric cavity and the shell surface of a spindle (3) movable therein. One or the other surface is provided with an annular groove (9), in which a sealing ring (8) is located, which is slightly movable in axial and radial direction and intended to minimize fluidum leakage in axial direction between the co-operating surfaces. The ring when located in a groove in the cylindric cavity extends with the sealing surface about the inner surface of the ring, and when located in a groove in the spindle extends with the sealing surface about the outer surface of the ring. By permitting a certain small leakage past the sealing surfaces and by utilizing the hydraulic conditions then prevailing, the friction is eliminated and substantially better sealing properties are obtained. The ring (8) has small cross-sectional dimensions in relation to the spindle (3) and enclosing cavity. The ring is so slim that dimensioning fluidum pressure over the ring is capable to change the diameter of the ring, but is of such rigid material that deformation of the cross -section of the ring is negligible compared to the change in diameter of the ring. The sealing surface (12) of the ring is slightly conic, and the ring is located so that the sealing surface at co-operation with the sealing surface of either the cavity or spindle forms a gap (14), the height ( > 0) of which decreases in the direction to that side of the ring, against which sealing is to take place, i.e. in the leakage flow direction. The ring abuts on the lastmentioned side the radial inner surface (11) of the groove along a supporting surface, which is annular and has a substantially smaller height than the cross-sectional height of the ring and is located adjacent the sealing surface, so that the ring can be twisted out of its central plane, and said supporting surface has such a small height dimension relative to the axial dimension of the ring, that the friction force in the supporting surface can be overcome by forces acting radially on the ring. One or more grooves are located in peripheral direction about the inner surface of the ring. The grooves 33 distribute the pressure from the medium about the ring, so that the ring cannot abut the sealing surface and be jammed. Fig. 3 to be published.