Patent ID: 7908936

Claim:
A system for providing a gas stream having an adjustable known humidity, comprising: (a) a source of a gas having an initial relative humidity, (b) a supply line in fluid communication with the gas source for directing gas from the gas source to a destination point, the supply line including: (i) a wet path effective for humidifying gas from the gas source passing along the wet path to a first known relative humidity greater than the initial relative humidity, (ii) a dry path effective for maintaining the initial relative humidity of gas from the gas source passing along the dry path, and (iii) a junction point downstream from the wet and dry paths and upstream from the destination point, where gas passing along the wet and dry paths are merged prior to delivery to the destination point, and (c) at least one valve in fluid communication with the supply line for mutually exclusively effecting gas flow from the gas source along the wet path or the dry path, (d) whereby (i) effecting gas flow along the wet path only provides the destination point with a gas having the first known relative humidity, (ii) effecting gas flow along the dry path only provides the destination point with a gas having the initial relative humidity, and (iii) alternating gas flow along the wet and dry paths on a predetermined duty cycle provides the destination point with a gas having a known relative humidity between the initial relative humidity and the first relative humidity.