Abstract: A system for evacuating an enclosure is provided. The system comprises first pumping means having an inlet selectively connectable to an outlet from the enclosure. Second pumping means are also provided together with conduit means for connecting an exhaust of the first pumping means to an inlet of the second pumping means. An auxiliary chamber is provided, this chamber being selectively connectable to the conduit means such that, in a first state, gas can be drawn from the auxiliary chamber by the second pumping means in isolation from the enclosure, and, in a second state, gas can be drawn from the enclosure to the auxiliary chamber through the first pumping means.

Abstract: A seal assembly for the protection of a static seal device for use in a vacuum pump. The seal assembly comprising at least two components which are sealingly connected together, an o-ring seal, which is engaged between the two components to prevent transfer of fluid to and from the pump between these two components and a fluid channel. The fluid channel being in the plane of the o-ring and located between the o-ring seal and a process gas flow path. The fluid channel provides a path for a barrier gas to be routed when the apparatus is in use. The channel being connectable to an external source of barrier fluid and having an outlet in fluid communication with the pump swept volume.