Gas Sample Collection and Analysis

Abstract

A system and method for capturing a sample gas for analysis is disclosed. In one embodiment, the system includes an accumulator that has a variable volume. A volume of the sample gas is fed to the accumulator. The system also has an analyzer. An aliquot of the sample gas is withdrawn from the accumulator and fed to the analyzer. The analyzer analyzes a desired component of the sample gas.

1 . A sample-gas dispensing system, comprising:
 a sample gas source, configured to feed a sample gas;   a variable-volume accumulator configured to accumulate an increasing volume of the sample gas;   an analyzer, wherein the variable-volume accumulator is configured to dispense a first aliquot of the sample gas to the analyzer,   wherein the variable-volume accumulator is simultaneously coupled to the sample gas source and the analyzer.   
     
     
         2 . The system of  claim 1 , wherein the accumulator comprises a chamber, and wherein the chamber comprises a sample side and a pressure side, and further wherein the sample side contains a variable volume of the sample gas. 
     
     
         3 . The system of  claim 2 , wherein the chamber comprises a chamber separator that separates the sample side from the pressure side and prevents flow of gas between the sample side and the pressure side, and wherein the chamber separator comprises a flexible membrane that is impermeable by gas. 
     
     
         4 . The system of  claim 2 , wherein the chamber comprises a flexible bag that prevents flow of sample gas to the pressure side, and wherein the flexible bag is impermeable by gas. 
     
     
         5 . The system of  claim 2 , wherein a valve allows the pressure side to be open to the atmosphere when the sample gas is fed to the sample side. 
     
     
         6 . The system of  claim 2 , wherein a purge gas fed to the pressure side forces the sample gas out of the sample side, and wherein a valve closes the sample side to the analyzer and opens the sample side to a vent to atmosphere. 
     
     
         7 . The system of  claim 1 , wherein the accumulator comprises a flexible bag that is impermeable by gas. 
     
     
         8 . The system of  claim 7 , further comprising a vacuum, wherein the vacuum removes sample gas from the flexible bag. 
     
     
         9 . The system of  claim 8 , wherein a purge gas is fed to the flexible bag to purge the flexible bag after the vacuum removes the sample gas from the flexible bag. 
     
     
         10 . The system of  claim 9 , wherein the purge gas is removed from the flexible bag by the vacuum. 
     
     
         11 . The system of  claim 1 , wherein the sample gas source comprises a combustion furnace. 
     
     
         12 . The system of  claim 1 , wherein the system is operated at atmospheric pressure. 
     
     
         13 . The system of  claim 1 , wherein the accumulator comprises a single gas orifice, wherein the single gas orifice is simultaneously coupled with the sample gas source and the analyzer. 
     
     
         14 . The system of  claim 1 , wherein the accumulator comprises a single gas orifice, wherein the single gas orifice is simultaneously coupled with the variable-volume sample gas source and a purge gas source or a vacuum. 
     
     
         15 . The system of  claim 1 , wherein the variable-volume accumulator is configured to dispense a second aliquot of sample gas to the analyzer. 
     
     
         16 . The system of  claim 15 , wherein the second aliquot of sample gas has a different volume than the first aliquot of sample gas. 
     
     
         17 . A sample-gas dispensing system, comprising:
 a sample gas source;   a sample gas analyzer;   accumulator means for accumulating sample gas in a variable volume and releasing first and second aliquots of sample gas to the sample gas analyzer,   wherein the sample gas source, the accumulator means, and the sample gas analyzer are simultaneously coupled together.   
     
     
         18 . The apparatus of  claim 17 , wherein the accumulator means comprises a chamber, and wherein the chamber comprises a variable-volume sample side and a pressure side. 
     
     
         19 . The apparatus of  claim 18 , wherein the chamber comprises a gas-impermeable flexible membrane interposed between the sample side and the pressure side. 
     
     
         20 . The apparatus of  claim 17 , wherein the accumulator means comprises a flexible bag that is impermeable by gas. 
     
     
         21 . The, apparatus of  claim 20 , further comprising means for purging the flexible bag of the sample gas by a vacuum. 
     
     
         22 . The apparatus of  claim 17 , wherein the volume of sample gas in the second aliquot is different from the volume of sample gas in the first aliquot. 
     
     
         23 . The system of  claim 17  wherein the sample gas source comprises a combustion furnace. 
     
     
         24 . A sample-gas dispensing system, comprising:
 a combustion furnace configured to emit a sample gas;   a variable-volume flexible bag coupled to the combustion furnace, the variable-volume flexible bag configured to accumulate an increasing volume of the sample gas emitted by the combustion furnace;   an analyzer coupled to the variable-volume flexible bag; and   means for dispensing a first aliquot and a second aliquot of sample gas from the variable-volume flexible bag to the analyzer.   
     
     
         25 . The system of  claim 24 . wherein the first and second aliquots have different volumes.