Analysis device for determining particulate matter
An optical analysis device for determining particulate matter includes three light sources having different wavelengths, an apparatus for combining the three transmitted light beams on a common optical path, a measurement volume, an optical axis in the forward scattering direction defines the scattering angle 0°, a light absorption apparatus at 0° that absorbs unscattered light, and six detectors which are arranged at different specified angles which are as close as possible to 0° directly next to the light absorption apparatus, at a second scattering angle between 7° and 40°, at a third scattering angle between 41° and 70°, at a fourth scattering angle between 71° and 115°, at a fifth scattering angle between 116° and 145°, at a sixth scattering angle between 146° and 180°. A control and evaluation unit controls the light sources such that the scattered light is detected in a wavelength selective manner by the detectors.
1. An optical analysis device ( 10 ) for determining particulate matter, said optical analysis device ( 10 ) comprising,
three light sources (L 1 , L 2 , L 3 ) for transmitting three transmitted light beams (S 1 , S 2 , S 3 ) having different wavelengths;
an apparatus ( 22 ) for combining the three transmitted light beams (S 1 , S 2 , S 3 ) on a common optical path ( 24 );
a measurement volume ( 25 ) into which gas charged with particulate matter can be introduced and in which the transmitted light (S 1 , S 2 , S 3 ) is incident on the gas to be measured and is scattered at the particulate matter and a center ( 29 ) is defined in the measurement volume from where scattering angles (α) are defined, with the optical axis in the forward scattering direction defining the scattering angle 0°;
a light absorption apparatus ( 30 ) at 0° that detects unscattered light;
a first detector ( 40 ) that is arranged as close as possible to 0° directly next to the light absorption apparatus ( 30 ) and that detects scattered light in the forward direction;
a second detector ( 42 ) that is arranged at a second scattering angle between 7° and 40°;
a third detector ( 44 ) that is arranged at a third scattering angle between 41° and 70°;
a fourth detector ( 46 ) that is arranged at a fourth scattering angle between 71° and 115°;
a fifth detector ( 48 ) that is arranged at a fifth scattering angle between 116° and 145°;
a sixth detector ( 50 ) that is arranged at a sixth scattering angle between 146° and 180° so that the detectors detect scattered light at the respective angle;
a control and evaluation unit ( 60 ) comprising a computer and memory that controls the light sources (L 1 , L 2 , L 3 ) using algorithms such that the scattered light is detected in a wavelength selective manner by the detectors ( 40 , 42 , 44 , 46 , 48 , 50 );
a memory ( 62 ) for storing the detected scattered light intensities;
and the control and evaluation unit ( 60 ) using algorithms to ultimately determine the size distribution of the particular matter and the particular matter mass percentages from the scattered light intensities.
2. The analysis device in accordance with claim 1 , characterized in that
the first scattering angle is between 0° and 6°;
the second scattering angle is between 23° and 33°;
the third scattering angle is between 56° and 66°;
the fourth scattering angle is between 91° and 101°;
the fifth scattering angle is between 125° and 135°;
the sixth scattering angle is between 145° and 165°.
3. The analysis device in accordance with claim 2 , characterized in that a seventh detector is arranged in a seventh scattering angle range between 166° and 180° C.
4. The analysis device in accordance with claim 2 , characterized in that the transmitted light is linearly polarized.
5. The analysis device in accordance with claim 2 , characterized in that the first detector is configured as a CMOS line sensor.
6. The analysis device in accordance with claim 2 , characterized in that each detector has an optics that detects the light from a scattered light tolerance range of +/−1° and focuses it on the detector.
7. The analysis device in accordance with claim 2 , characterized in that the apparatus for beam combination is either implemented with fixed-position mirrors or has a pivotable parabolic mirror that can conduct the transmitted light of each of the three light sources on the one optical path in dependence on the pivot angle position.
8. The analysis device in accordance with claim 2 , characterized in that the wavelengths of the light sources are in the ultraviolet range, visible range, and infrared range.
9. The analysis device in accordance with claim 2 , characterized in that the transmitted light beams are expanded and have a diameter of approximately 4 mm in the region of the measurement volume.
10. The analysis device in accordance with claim 2 , characterized in that the amplified detector signals are calibrated to physical units by means of test particles having a known size distribution and known optical properties.
11. The analysis device in accordance with claim 1 , characterized in that
the first scattering angle is between 0° and 6°;
the second scattering angle is approximately 28°;
the third scattering angle is approximately 61°;
the fourth scattering angle is approximately 96°;
the fifth scattering angle is approximately 128°; and
the sixth scattering angle is approximately 155°.
12. The analysis device in accordance with claim 11 , characterized in that a seventh detector is arranged in a seventh scattering angle range between 166° and 180° C.
13. The analysis device in accordance with claim 11 , characterized in that a seventh detector is arranged in a seventh scattering angle range of approximately 170°.
14. The analysis device in accordance with claim 11 , characterized in that the transmitted light is linearly polarized.
15. The analysis device in accordance with claim 11 , characterized in that the first detector is configured as a CMOS line sensor.
16. The analysis device in accordance with claim 11 , characterized in that each detector has an optics that detects the light from a scattered light tolerance range of +/−1° and focuses it on the detector.
17. The analysis device in accordance with claim 11 , characterized in that the apparatus for beam combination is either implemented with fixed-position mirrors or has a pivotable parabolic mirror that can conduct the transmitted light of each of the three light sources on the one optical path in dependence on the pivot angle position.
18. The analysis device in accordance with claim 11 , characterized in that the wavelengths of the light sources are in the ultraviolet range, visible range, and infrared range.
19. The analysis device in accordance with claim 11 , characterized in that the transmitted light beams are expanded and have a diameter of approximately 4 mm in the region of the measurement volume.
20. The analysis device in accordance with claim 11 , characterized in that the amplified detector signals are calibrated to physical units by means of test particles having a known size distribution and known optical properties.