Spectrometer and a fluid analysis system

Patent metadata

Field	Value
Publication number	US-9528877-B2
Application number	US-201514607745-A
Country	US
Kind code	B2
Filing date	Jan 28, 2015
Priority date	Feb 3, 2014
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A spectrometer, in particular for being installed in a sensor module of a fluid analysis system, including a radiation source and the following components defining a beam path or being arranged along the beam path: a sample chamber for a fluid to be examined, a first lens, a diffraction element, a second lens and a detector. A restriction aperture for restricting the effective diameter of the light beam incident on the diffraction element is provided between the sample chamber and the diffraction element.

First claim

The invention claimed is:

1. A spectrometer, in particular for being installed in a sensor module, comprising a radiation source and the following components defining a beam path or being arranged along the beam path:
a sample chamber for a fluid to be examined,
a first lens,
a diffraction element,
a second lens, and
a detector,
wherein a restriction aperture for restricting the effective diameter of the light beam incident on the diffraction element is provided between the first lens and the diffraction element, and wherein the light beam is not focused at any point before reaching the diffraction element.

2. The spectrometer according to claim 1 , wherein the width (d) of the restriction aperture is considerably smaller than the diameter of the first lens.

3. The spectrometer according to claim 1 , wherein the width (d) of the restriction aperture is in a range of between 0.1 and 1.5 mm.

4. The spectrometer according to claim 1 , wherein the focal length of the first lens is in a range of between 3 and 7 cm, and/or in that the focal length of the second lens is in the range of between 2 and 5 cm.

5. The spectrometer according to claim 1 , wherein a sharpening factor defined as S=RB/d, wherein RB=image field radius and d=width of the restriction aperture, is greater than 10.

6. The spectrometer according to claim 1 , wherein the restriction aperture is located in a Fourier space, in which the light of the radiation source is collimated.

7. The spectrometer according to claim 1 , wherein the restriction aperture is formed by a narrow light channel in a component that is also used as a holder for the first lens.

8. The spectrometer according to claim 1 , wherein the restriction aperture is formed in a layer that is applied on the side of the first lens that faces the diffraction element.

9. The spectrometer according to claim 1 , wherein the detector is a linear detector, in particular a linear sensor.

10. The spectrometer according to claim 1 , wherein the maximum extension of the optically sensitive area of the detector is in the range of between 1 and 4 cm.

11. The spectrometer according to claim 1 , wherein the sample chamber has a length of several more than 4 cm, in the direction of the beam path.

12. The spectrometer according to claim 1 , wherein the sample chamber is connected to an inflow channel and an outflow channel, which open into the sample chamber via ring lines, wherein the ring lines are formed in a housing that surrounds the sample chamber.

13. The spectrometer according to claim 1 , wherein the diffraction element is formed as a mirror grating.

14. The spectrometer according to claim 1 , wherein the radiation source is a xenon flash lamp.

15. The spectrometer according to claim 1 , wherein an entrance aperture is additionally provided in the beam path.

16. The spectrometer according to claim 1 , wherein the sample chamber is provided in the beam path behind the entrance aperture.

17. The spectrometer according to claim 1 , wherein the sensor comprises a one-dimensional array of detector elements.

18. A fluid analysis system comprising a spectrometer according to claim 1 .

19. A fluid analysis system comprising a spectrometer according to claim 1 , wherein no entrance aperture is provided between the radiation source and the sample chamber, wherein the fluid analysis system further comprises an electronic unit that is configured to take into account a shift of the spectra acquired by the detector during an evaluation of multiple measurements.

20. The fluid analysis system according to claim 19 , wherein the electronic unit is configured such that an initial calibration is carried out by associating a characteristic maximum of the spectrum with a pixel of a sensor of the detector, and in that on the basis of this pixel, further pixels of the sensor are permanently associated with corresponding wavelengths.

21. The fluid analysis system according to claim 20 , wherein the electronic unit is configured such that each measurement is individually calibrated and/or corrected on the basis of a selected characteristic range of the detected spectrum in the form of an evaluation window, which is defined by a wavelength range or a pixel range of the sensor which corresponds to the wavelength range, and by an intensity range.

22. The fluid analysis system according to claim 21 , wherein the electronic unit is configured such that a shift between various measurements is calculated on the basis of the position of a maximum of the spectrum within the evaluation window, a corrected wavelength axis is determined for each acquired spectrum, and this adaptation is followed by averaging the measurements.

23. The fluid analysis system, comprising a sensor module having installed therein at least one spectrometer according to claim 1 , and an analysis unit, the fluid analysis system further comprising a locking clamp that can be used to fix the sensor module in the analysis unit whilst at the same time electrical and fluid connections are made.

24. A spectrometer, in particular for being installed in a sensor module, comprising a radiation source and the following components defining a beam path or being arranged along the beam path:
a sample chamber for a fluid to be examined,
a first lens,
a diffraction element,
a second lens, and
a detector,
wherein a restriction aperture for restricting the effective diameter of the light beam incident on the diffraction element is provided in the beam path immediately in front of the first lens, and wherein the light beam is not focused at any point before reaching the diffraction element.

25. The spectrometer according to claim 24 , wherein the restriction aperture is formed in a layer applied on the side of the first lens that faces the sample chamber.

26. The spectrometer according to claim 24 , wherein the restriction aperture is formed by a holder that immediately surrounds the first lens.

Assignees

• Buerkert Werke Gmbh

Inventors

• Garbos Martin
• Scholl Christoph

Classifications

• G01N2201/068

  Optics, miscellaneous · CPC title

• G01J3/18

  using diffraction elements, e.g. grating (gratings per se G02B) · CPC title

• G01N2201/061

  Sources · CPC title

• G01J2003/2866

  Markers; Calibrating of scan · CPC title

• G01N21/85

  Investigating moving fluids or granular solids · CPC title