Staged seal assembly for e.g. pump, mixer, has external pressure breakdown device fluidly connected to seal assembly and external device to allow passage of fluid directed by seal by-pass around shaft seal

摘要

An external pressure breakdown device (62) is fluidly connected to the seal assembly (10) and an external device. Staged seals (20a-20c), arranged in series along a shaft, individually have a shaft seal (30a-30c) and a seal by-pass (40a-40c). The seal by-pass directs fluid through the pressure breakdown device around the shaft seal. An independent claim is included for a non-staged seal assembly replacing method.