Dilution stack sampling apparatus

Dilution stack sampling apparatus for analyzing gaseous components of a gas stream containing particulate material therein, said apparatus comprising:

• a hollow probe assembly having a first distal upstream end for receiving a sample of gas from the gas stream, containing particulate material of varying size, from the stack to be analyzed and a second proximal downstream end;
• a passageway for receiving the sample of gas from the gas stream, said passageway having a first and second end, said first end communicating with said probe assembly, intermediate its ends, to cause a change in flow direction of the sample of gas to pass through said passageway to inertially remove most of the particulate material from the sample;
• means connected to said second end for mixing dilution air with the sample gas for discharge from said means as a diluted sample;
• a filter upstream of said second end of said passageway for removing the rest of the particulate matter from the sample of gas;
• said first end of said passageway is a cylindrical chamber surrounding said probe assembly;
• and
• said filter extends around the periphery of said chamber so that the sample gas flows past said proximal end of said probe assembly and back to said first end of said passageway and through said filter.

Dilution stack sampling apparatus for analyzing gaseous components of a gas stream containing particulate material therein, said apparatus comprising:

• a hollow probe assembly having a first distal upstream end for receiving a sample of gas from the gas stream, containing particulate material of varying size, from the stack to be analyzed and a second proximal downstream end;
• a passageway for receiving the sample of gas from the gas stream, said passageway having a first and second end, said first end communicating with said probe assembly, intermediate its ends, to cause a change in flow direction of the sample of gas to pass through said passageway to inertially remove most of the particulate material from the sample;
• means connected to said second end for mixing dilution air with the sample gas for discharge from said means as a diluted sample;
• a filter upstream of said second end of said passageway for removing the rest of the particulate matter from the sample of gas;
• and
• a conduit extending through at least a portion of said apparatus having a diameter greater than said proximal end of said probe assembly, said probe assembly being mounted concentrically therein, said first end of said passageway being in communication with said conduit between said ends of said probe assembly so that a portion of said sample gas flows around said proximal end of said probe assembly and reverses direction and flows back through said first end of said passageway.