Sealing arrangement and a sealing member therefor

Abstract

A sealing arrangement is designed for sealing a space that extends between high and low pressure areas and that is defined between a first apparatus part and a cylindrical surface of a second apparatus part, the first and second apparatus parts being mutually moveable in a reciprocating manner along the axis of said cylindrical surface. The sealing arrangement includes an annular sealing member of resilient material having a radially outer peripheral surface extending between axially opposite first and second end surfaces facing the high and low pressure areas, respectively, and a radially inner peripheral surface for providing a sealing engagement with the cylindrical surface of the second apparatus part at a contact area, and for defining with the cylindrical surface a first space widening or diverging from the contact area toward the low pressure area. A compression ring surrounds the annular sealing member, and is in contact with the outer peripheral surface of the annular sealing member so as to press the inner peripheral surface thereof into close contact with the cylindrical surface of the second apparatus part at the contact area. The axial sectional view of at least part of the outer peripheral surface of the annular sealing member comes into contact with the compression ring, defining such convex contour that in an unstressed condition of the sealing member, the radial distance between such part of the outer peripheral surface and the radially innermost part of the inner peripheral surface decreases in an axial direction toward the second end surface and the low pressure area, with the radius or radii of curvature of the convex contour being at least 0.4 times the total axial length or width of the annular sealing member.