EVALUATION OF SEAL PRESSURE ON THE SHAFT

Abstract

A lip-type seal is a device installed between the shaft and the casing to avoid contact between two environments shared by the seal. Sealing is ensured by pressuring to the shaft due to its deformation and additionally by means of a band spring stretched around the lip-type seal. An important parameter to ensure the seal operation is the seal contact pressure on the shaft. This paper examines the contact pressure provided by the spring without taking into account the lip-type seal deformation outside the contact area with the shaft. The study aimed at assessing the relationship between the radial lip-type seal pressure on the shaft and the spring stretching force and material properties in the seal contact area with the shaft. Using the methods of elasticity theory, the authors obtained expressions for radial and circular normal stresses on the boundary cylindrical surfaces of the seal. The study established a functional relationship between the seal contact pressure on the shaft and the spring stretching (per unit diameter of the shaft) and the elasticity coefficient (modulus) of the sealing material. The obtained relationship can be used to determine the pressure increase arising from the growing spring stretching intensity and the elasticity coefficient.