Design of Split Mechanical Seal

Abstract

Split mechanical seal has an advantage over conventional type (non-split type) mechanical seal in the area of sealing of large rotary equipment, as it takes very less installation time and it can be installed without removing any component of rotary equipment. Many theories regarding the different parameters afecting design of split mechanical seal have been published, however, literatures which discusses the com- plete design procedure of split mechanical seal is not readily available. An attempt is made in this work to prepare the design guidelines for split mechanical seal. In this work, general design guidelines for primary sealing are prepared by calculating proper balance ratio and stiffness of a exible element. An agitator seal designed us- ing the prepared guidelines is tested to justify the design process of both primary and secondary sealing. For the applications where leakage is major concern, a methodol- ogy to calculate the minimum balance ratio is described by considering seal ring face geometry, shaft run outs and the process parameter uctuations. In split mechani- cal seal rings, since the leakage across mating faces of split halves is major concern, a testing procedure is presented for checking of any leakage before the installation. Split seal is designed for centrifugal blower to demonstrate the calculation of design parameters following the design guidelines.