| 摘要 |
PROBLEM TO BE SOLVED: To carry out continuous removal of impurities in a sample gas to be introduced to a gas analyzer by arranging a plurality of gas channels with filter elements in parallel and switching to a gas channel with an uncontaminated filter element at the time when the gas channel introduced the sample gas is contaminated. SOLUTION: The quantity of flow of sample gas collected from a flow of gas to be measured is regulated to a quantity of gas necessary for gas analysis via a valve 5, and the sample gas is introduced to one of gas channels with filter elements 4 via the gas channel switching valve 3 of a filtering means 1 to remove impurities. Furthermore, the sample gas in the filtering means 1 is introduced to a cleaning means 2 via the valve 5 and is bubbled through a bubbler 6 filled with a cleaning solvent 7 to remove residual impurities. In addition, the internal pressure of the gas channel is measured by a pressure gauge provided between the filter element 4 and the gas channel switching valve 3 during analysis, and another gas channel with an uncontaminated filter element 4 is selected by the valve 3 at the time when the internal pressure is lowered to a specified value.
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