发明名称 |
Photoacoustic measurement of unburned carbon in fly-ash |
摘要 |
The present invention provides a method and an apparatus for measuring the amount of unburned carbon in a sample of fly ash using infrared photoacoustic absorption. One preferred method according to the present invention involves directing modulated infrared radiation at a sample of fly ash and measuring the acoustic signal produced when the unburned carbon in the sample absorbs the radiation producing a thermal wave which propagates through the sample to generate a minute acoustic wave at interfaces between the carbon particles and gas surrounding the particles. One preferred apparatus includes a source of modulated infrared radiation, a chamber for containing the sample, a microphone to detect the acoustic signals, lock-in amplifier to separate the desired photoacoustic signal from noise at other frequencies, and a PC computer to provide output from the amplifier. This apparatus identifies the acoustic signal for determination of the amount of unburned carbon in the sample.
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申请公布号 |
US5596146(A) |
申请公布日期 |
1997.01.21 |
申请号 |
US19940254153 |
申请日期 |
1994.06.06 |
申请人 |
IOWA STATE UNIVERSITY RESEARCH FOUNDATION, INC. |
发明人 |
WALLER, DAVID;BROWN, ROBERT C. |
分类号 |
G01N21/17;G01N29/032;G01N29/24;(IPC1-7):G01N29/00 |
主分类号 |
G01N21/17 |
代理机构 |
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地址 |
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