Abstract: A seal arrangement for a stuffing box, the stuffing box having an outboard seal an inboard seal exposed to process fluid, and a volume pressurized with barrier fluid in which the inboard seal and the outboard seal are disposed, has a container divided into at least two non-communicating chambers by a movable wall, with a first of the chambers being supplied with barrier fluid and communicating with the space in the stuffing box in which the outboard seal is disposed, and a second of the chambers communicating with the stuffing box so as to be at the stuffing box pressure. The movable wall constantly strives to assume an equilibrium position wherein substantially no pressure differential exists across the inboard seal. Due to the absence of such a pressure differential, substantially no contamination of the barrier fluid by the process fluid occurs, and vice versa.

Abstract: A seal arrangement for a stuffing box, the stuffing box having an outboard seal an inboard seal exposed to process fluid, and a volume pressurized with barrier fluid in which the inboard seal and the outboard seal are disposed, has a container divided into two non-communicating chambers by a movable wall, with a first of the chambers being supplied with barrier fluid and communicating with the space in the stuffing box in which the outboard seal is disposed, and a second of the chambers communicating with the stuffing box so as to be at the stuffing box pressure. The movable wall constantly strives to assume an equilibrium position wherein substantially no pressure differential exists across the inboard seal. Due to the absence of such a pressure differential, substantially no contamination of the barrier fluid by the process fluid occurs, and vice versa.