PURGING APPARATUS FOR SPECTROMETRIC DEVICE

PROBLEM TO BE SOLVED: To obtain a purging apparatus by which the air inside a spectrometric device is replaced easily by a gas by a method wherein a four-way stopcock is provided and, when a flow passage on one side sets a supply passage into continuity with an interferometer-side introduction passage, a flow passage on the other side sets an interferometer-side derivation passage into continuity with the introduction passage. SOLUTION: A four-way stopcock 40 in which a flow passage 42 and a flow passage 44 are formed is operated. Then, a purge gas from a supply means 20 is introduced into a purging case 12, for exclusive use, via a supply passage 22, the flow passage 42 and an interferometer-side introduction passage 24. When the purge gas is introduced into the purging case 12 for exclusive use, the air which contains carbon dioxide and moisture inside the ourging case 12 for exclusive use is replaced by a purge gas such as a dry gas or the like. In addition, the purging gas which is introduced into the ourging case 12 is reintroduced into a purging case 16, for combined use, via an interferometer-side derivation passage 26, the flow passage 44 and an introduction passage 30. As a result, the air inside a spectrometric device 10 can be replaced efficiently by the dry air, and the purge gas can be used effectively.