Patent ID: 7879137

Claim:
A purge gas mixture supply system, comprising: a purge gas mixture generator comprising a moisturizer configured to add moisture to a purge gas, wherein said moisturizer comprises a first region containing a purge gas flow and a second region containing water wherein the first and second regions are separated by a membrane contactor that forms a hollow fiber that is gas permeable and substantially resistant to liquid intrusion, one of the first and second regions being within the fiber and the other of the first and second regions being outside the fiber; the purge gas mixture generator being configured to add the moisture to the purge gas by further comprising a mass flow controller to control flow rate of the purge gas flow through the first region of the moisturizer and a pressure regulator to control flow of the water through the second region of the moisturizer such that the moisture is added to the purge gas to create a humidified purge gas mixture; and a purge gas mixture outlet being connected to the purge gas mixture generator to supply the humidified purge gas mixture to at least part of a lithographic projection apparatus.