Patent ID: 8650973

Claim:
A diluter for diluting a sample flow of test gas to allow subsequent measurement of emissions contained in the test gas with an instrument, comprising: a dilution control unit for receiving and controlling a dilution flow into the diluter at a controlled dilution flow rate; a sample gas inlet for receiving the sample flow; a mixer connected to the dilution control unit and to the sample gas inlet for receiving and mixing the dilution flow and sample flow to provide a mixed flow; a bypass line for carrying the dilution flow around the mixer during a calibration mode of the diluter; a valve for directing the dilution flow into the mixer or into the bypass line; a vacuum source for pulling flow through the diluter; an indirect sample flow control unit downstream the mixer, operable to indirectly control the sample flow rate during a measurement phase of the diluter; a total flow control unit downstream the mixer, operable to receive and measure only the dilution flow from the bypass line, during a calibration mode of the diluter; the total flow control unit further operable to control the mixed flow at a controlled flow rate and deliver a portion of the mixed flow to the instrument, during a measurement mode of the diluter.