Patent ID: 8684031

Claim:
An apparatus for conveying waste streams exhausted from first and second vacuum process chambers, the apparatus comprising: a first conduit comprising: an inlet for receiving a waste stream exhausted from the first chamber, an outlet, means for locally reducing the cross sectional area of part of the first conduit to increase the local density of gas being conveyed towards the outlet of the first conduit to an extent which inhibits migration of a component of the waste stream exhausted from the second vacuum process chamber towards the first vacuum process chamber, and a gas port located upstream of the means for locally reducing the cross sectional area; a purge gas source configured to supply purge gas to the gas port at a given pressure and mass flow rate to establish a steady state flow regime at the means for locally reducing the cross sectional area; and a second conduit comprising an inlet for receiving a waste stream exhausted from a second chamber, and an outlet, wherein the outlets of the first conduit and second conduit are in fluid communication.