Patent ID: 7798020

Claim:
A dilution apparatus for sampling of a source gas emitted from a source, said apparatus comprising: a flowmeter, said flowmeter adapted to measuring a parameter indicative of flow rate of the source gas; a mixing chamber, said mixing chamber adapted to mixing a portion of the source gas with a dilution gas, thereby generating a diluted sample; first flow control, said first flow control adapted to at least partially controlling the flow rate of the portion of the source gas, said first flow control comprising a first parallel array of solenoid valves, each defining a flow restriction, wherein at least one of said flow restrictions comprises an adjustable critical flow restriction; a processing unit responsive to an output of said flowmeter, said processing unit controlling the sampling ratio of the source gas by activating a combination of said solenoid valves of said first parallel array as a function of the flow rate of the source gas.