Abstract: The present disclosure relates to vacuum pump 10 comprising a substantially hermetically sealed enclosure 40, a core pump assembly located within the enclosure 40, and an inert purge gas inlet 70 fluidly connected to the enclosure 40 for supplying inert purge gas to an interior of the enclosure 40 surrounding the core pump assembly. By providing a sealed enclosure 40 around the core pump assembly and supplying inert purge gas thereto via the inlet 70, an inert positive pressure can be applied to the core pump assembly that reduces leakage of process gas from the core pump assembly such that seals therein can be removed or reduced. In particular, the need for elastomer seals that may be expensive and not be suited to high temperature or corrosive process gas conditions can be removed.

Abstract: A vacuum system non-return valve includes a baffle for extending across a flow path in the vacuum system and a valve member. The baffle has an aperture, a perimeter of the aperture has a valve seat. The valve member has a curved sealing surface configured to mate with the valve seat. The valve member and aperture are configured such that the valve member obscures the aperture and seals with the valve seat to impede a flow of fluid in a closed position and is displaceable in use to move away from the valve seat and allow a fluid flow in an open position; at least a portion of the surface of the baffle surrounding the aperture slopes towards the inlet end of the valve such that the aperture is smaller at the inlet end than it is at the outlet end.

Abstract: A vacuum system non-return valve includes a baffle for extending across a flow path in the vacuum system and a valve member. The baffle has an aperture, a perimeter of the aperture has a valve seat. The valve member has a curved sealing surface configured to mate with the valve seat. The valve member and aperture are configured such that the valve member obscures the aperture and seals with the valve seat to impede a flow of fluid in a closed position and is displaceable in use to move away from the valve seat and allow a fluid flow in an open position; at least a portion of the surface of the baffle surrounding the aperture slopes towards the inlet end of the valve such that the aperture is smaller at the inlet end than it is at the outlet end.

Abstract: A vacuum system non-return valve has a baffle for extending across a flow path The baffle has an aperture, a perimeter of the aperture having a valve seat. The valve also has a valve member having a protrusion extending from a surface configured to mate with the valve seat, the protrusion extending through the aperture; wherein the protrusion includes a retaining portion extending outwardly from the protrusion and configured such that the retaining portion cannot pass through the aperture. The valve member and aperture are configured such that the valve member obscures the aperture and seals with the valve seat to impede a flow of fluid from an outlet end to an inlet end in a closed position and is displaceable in use to move away from the valve seat and allow a fluid flow from the inlet end to the outlet end in an open position.