Apparatus and method for producing a gas having a controlled water vapor content

摘要

An apparatus (10) and method for producing a gas having a controlled water vapor content is disclosed. Present methods of adding varying amounts of water to a gas containing nitric oxide may undesirably alter the composition of the gas. The present invention solves the above problem by providing an apparatus (10) and method for substantially fully saturating an unconditioned gas, subsequently removing water from a preselected portion of the saturated gas, and then mixing the preselected dry and saturated portions of the gas. The present invention is particularly useful in calibrating exhaust emission analyzers.