초록 ▼

The present invention provides a NOx-concentration measuring apparatus D for quantitatively analyzing the concentration of NOx contained in a sample gas. The measuring apparatus D comprises a sampling probe for obtaining the sample gas, a drain separator 2 for condensing moisture contained in the sa

The present invention provides a NOx-concentration measuring apparatus D for quantitatively analyzing the concentration of NOx contained in a sample gas. The measuring apparatus D comprises a sampling probe for obtaining the sample gas, a drain separator 2 for condensing moisture contained in the sample gas as a condensed water and separating the condensed water from the sample gas, an NO2 converter 3 for converting NO2 contained in the sample gas into NO, a secondary cooling device 7 for additionally cooling the sample gas, and an NO analyzer 1, arranged in this order with respect to a sample-gas line of the NOx-concentration measuring apparatus. The drain separator is a high-flow-velocity cooling type drain separator.Further, the sample-gas line between the sampling probe and the drain separator is heated and/or thermally insulated over the entire length thereof. The measuring apparatus can provide a high-precision measurement while suppressing NO2 loss.

대표청구항 ▼

1. A NOx-concentration measuring apparatus for quantitatively analyzing the concentration of NOx contained in a sample gas, comprising:a sampling probe for obtaining the sample gas; a drain separator for condensing moisture contained in the sample gas as a condensed water and separating the condense

1. A NOx-concentration measuring apparatus for quantitatively analyzing the concentration of NOx contained in a sample gas, comprising:a sampling probe for obtaining the sample gas; a drain separator for condensing moisture contained in the sample gas as a condensed water and separating the condensed water from the sample gas, said drain separator having a cooling device therein for cooling the sample gas; an NO2 converter for converting NO2 contained in the sample gas into NO; a secondary cooling device for additionally cooling the sample gas; and an NO analyzer, arranged in above stated order with respect to a sample-gas line of said NOx-concentration measuring apparatus, wherein said drain separator is operable to cool the sample gas passing therethrough at a high flow velocity such that a ratio of the flow rate (cm3/min) of said sample gas passing through said drain separator to the internal volume (cm3) of said drain separator is set at 10 (min?1) or more; and the sample-gas line between said sampling probe and said drain separator is heated and/or thermally insulated over the entire length thereof. 2. A NOx-concentration measuring apparatus for quantitatively analyzing the concentration of NOx contained in a sample gas, comprising:a sampling probe for obtaining the sample gas; a drain separator for condensing moisture contained in the sample gas as a condensed water and separating the condensed water from the sample gas, said drain separator having a cooling device therein for cooling the sample gas; an NO2 converter for converting NO2 contained in the sample gas into NO; a secondary cooling device for additionally cooling the sample gas; and an NO analyzer, arranged in above stated order with respect to a sample-gas line of said NOx-concentration measuring apparatus, wherein said drain separator is provided with a sample-gas passage serving as a part of said sample-gas line, a ratio of the flow rate (cm3/min) of the sample gas passing through said drain separator to the internal surface area (cm2) of said sample-gas passage is set at 15 (cm/min) or more, and the sample-gas line between said sampling probe and said drain separator is heated and/or thermally insulated over the entire length thereof. 3. A NOx-concentration measuring apparatus for quantitatively analyzing the concentration of NOx contained in a sample gas, comprising:a sampling probe for obtaining the sample gas; a drain separator for condensing moisture contained in the sample gas as a condensed water and separating the condensed water from the sample gas, said drain separator having a cooling device for cooling the sample gas; an NO2 converter for converting NO2 contained in the sample gas into NO; a secondary cooling device for additionally cooling the sample gas; and an NO analyzer, arranged in above stated order with respect to a sample-gas line of said NOx-concentration measuring apparatus, wherein said drain separator is operable to cool the sample gas passing through a sample-gas passage, formed therein to serve as a part of said sample-gas line, at a high flow velocity such that a ratio of the flow rate (cm3/min) of said sample gas passing through said drain separator to the internal volume (cm3) of said drain separator is set at 10 (min?1) or more, and a ratio of the flow rate (cm3/min) of said sample gas passing through said drain separator to the internal surface area (cm2) of said sample-gas passage is set at 15 (cm/min) or more, and the sample-gas line between said sampling probe and said drain separator is heated and/or thermally insulated over the entire length thereof. 4. The NOx-concentration measuring apparatus as defined in claim 1, wherein said drain separator and said secondary cooling device are incorporated in a single unit.5. The NOx-concentration measuring apparatus as defined in claim 2, wherein said drain separator and said secondary cooling device are incorporated in a single unit.6. The NOx-concentration measuring apparatus as defined in claim 3, wherein said drain separator and said secondary cooling device are incorporated in a single unit.