GB2402493A - Optical relay with deflectors for analysing samples - Google Patents
Optical relay with deflectors for analysing samples Download PDFInfo
- Publication number
- GB2402493A GB2402493A GB0312751A GB0312751A GB2402493A GB 2402493 A GB2402493 A GB 2402493A GB 0312751 A GB0312751 A GB 0312751A GB 0312751 A GB0312751 A GB 0312751A GB 2402493 A GB2402493 A GB 2402493A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sample
- spectrometer
- optical relay
- radiation
- window
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 41
- 230000005855 radiation Effects 0.000 claims abstract description 41
- 238000001514 detection method Methods 0.000 claims abstract description 18
- 238000004458 analytical method Methods 0.000 claims abstract description 15
- 230000004888 barrier function Effects 0.000 claims description 3
- 239000000463 material Substances 0.000 abstract description 10
- 239000004033 plastic Substances 0.000 abstract description 10
- 229920003023 plastic Polymers 0.000 abstract description 10
- 239000008187 granular material Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 238000004566 IR spectroscopy Methods 0.000 description 1
- 238000000862 absorption spectrum Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
- G01J3/0208—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
- G01J3/021—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using plane or convex mirrors, parallel phase plates, or particular reflectors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0289—Field-of-view determination; Aiming or pointing of a spectrometer; Adjusting alignment; Encoding angular position; Size of measurement area; Position tracking
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0291—Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/08—Beam switching arrangements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J2003/2866—Markers; Calibrating of scan
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N2021/3595—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light using FTIR
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3563—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing solids; Preparation of samples therefor
Abstract
An optical relay 10 for an Infra Red spectrometer is disclosed having a housing to be located between the source and detection windows of a spectrometer. The relay 10 comprises a sample window 12 against which a sample may be placed for analysis by the spectrometer. The relay 10 also has a sample holder 14 for introducing a sample into the housing for analysis by the spectrometer. Two systems of deflectors 23,24,26,28 are arranged within the housing for selectively deflecting the IR radiation of the spectrometer to analyse a sample placed against the sample window 12 or a sample introduced into the housing by means of the sample holder 14. The IR radiation may also be directed using concave mirrors 30,36. The apparatus are used in the identification of plastics material.
Description
Plastics Identification
Field of the invention
The present invention relates to identification of plastics materials based on IR spectroscopy.
Background of the invention
lo It is environmentally highly desirable to be able to recycle articles made of plastics materials. Recycling not only solves the problem of how to dispose of plastics articles but also reduces the depletion of the world's resources of fossil fuels. There is however a need to be is able to identify plastics material reliably so that different materials may be separated from one another.
Certain material, for example PET and PVC, which can be visually indistinguishable from one another, will contaminate one another. If mixed, these resins can release hydrochloric gases and PET resin is ruined if mixed with even a very small proportion of PVC.
It is already known to use IR (infrared) spectroscopy to distinguish between different plastics materials. This is based on the fact that each plastics material has a characteristic IR absorption spectrum and by analysing the spectrum of IR radiation transmitted through or reflected by a plastics material one can determine its composition.
Known spectrometers have a recess defined between two facing surfaces. IR radiation is emitted from a source window in one of the surfaces. After interacting with the analysis sample, the IR radiation is received in an aligned detection window in the other surface. Such a configuration is intended for transparent or translucent samples in which the IR radiation passes through the sample. - 2
To analyse opaque samples, it is known, for example from EP 0713082, to place in the recess on optical relay containing a system of deflectors. The deflectors intercept the IR radiation from the source window of the spectrometer and deflect it towards a nozzle-like sample window. When a sample to be analysed is placed against the window, the radiation reflected from the surface of the sample is deflected by the deflectors within the optical relay to the detection window of the spectrometer. Such an optical relay is not well suited to the analysis of samples that are in granular form because the incident radiation is scattered instead of being uniformly reflected by the sample.
An optical relay better suited for granular material is described in US-A4,479,058. Here, the sample is introduced by means of a sample holder into the housing of the optical relay and the latter comprises a system of deflectors that once again deflects the IR radiation from the source window onto the sample and deflects the reflected radiation towards the detection window of the spectrometer. While this relay can be used to analyse small samples, it is unsuitable for larger samples which will not fit within the sample holder.
Object of the invention In a plastics recycling station, the material for recycling can come in all shapes and sizes ranging from a large item such as a vehicle bumper to granules and the aim of the present invention is to provide a versatile optical cell that can be used with a wide variety of samples.
Summary of the invention
According to the present invention, there is provided an optical relay for an IR spectrometer comprising a housing to be located between the source and detection windows of a spectrometer, the relay comprising a sample window against - 3 which a sample may be placed for analysis by the spectrometer and a sample holder for introducing a sample into the housing for analysis by the spectrometer, wherein two systems of deflectors are arranged within the housing for selectively deflecting the IR radiation of the spectrometer to analyse a sample placed against the sample window or a sample introduced into the housing by means of the sample holder.
lo By providing an optical relay that has both a sample window and a sample holder, the invention enables both solids with flat surfaces and granules to be analysed by means of the same spectrometer, without the need to interchange optical relays. Removing one optical relay and fitting the spectrometer with another is time consuming.
Furthermore, optical relays are delicate instruments that can easily be damaged during their removal from and mounting on a spectrometer and while they are not in use.
The recess at the front of a spectrometer within which the optical relay is received can be regarded as a hollow cube with its front and top walls missing. The horizontal bottom wall of the cube is a base plate on which the optical relay is supported, the vertical side walls of the cube are the surfaces containing the source window and the detection window and the vertical rear wall is formed by the housing of the spectrometer. Such terms as "front", "top", "bottom", "forward", "above", "below", "vertical" and "horizontal" as used herein are all to be construed by reference to the orientation of the walls of the recess as described above.
In a preferred embodiment of the invention, the sample window is positioned forward of the line connecting the source and detection windows and the IR radiation is deflected in a horizontal plane to and from the sample window, whereas the sample holder is arranged above the line connecting the source and detection windows and the IR - 4 - radiation is deflected in a vertical plane to and from the sample in the sample holder.
The preferred embodiment of the invention enables the radiation paths associated with the sample window and the sample holder to be contained within the same optical relay by arranging the optical paths in orthogonal planes.
Preferably, the optical relay comprises deflectors that lo are movable in synchronism with the sample holder so that the radiation light path through the optical relay is selected automatically in dependence upon whether the sample holder is pushed in or pulled out. In this way, the operation of the optical relay is rendered fool proof. While a sample is inserted into the optical relay by pushing in the sample holder, the spectrometer will be automatically configured to analyse the radiation reflected from the sample. With the sample holder pulled out, on the other hand, the IR radiation will automatically be directed toward the sample window for analysis of large sample placed against the window.
Brief description of the drawings
The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an optical relay in accordance with the invention, JO Figures 2A and 2B are a schematic plan views of a carrier movable with the sample holder, Figure 2A showing it in its position when the sample holder is pulled out and Figure 2B showing it in its position when the sample holder is pushed in, and Figure 3 is a schematic vertical section through the optical relay showing the path of the IR radiation when analysing a sample supported on the sample holder. - 5 -
Detailed description of the preferred embodiment -
Figure 1 shows an optical relay 10 designed and dimensioned to be inserted in the recess at the front of an = IR spectrometer (not shown). The construction and method of - operation of an IR spectrometer are well documented in the prior art (see for example the two references cited above) and will not be described further in the present context.
The optical relay 10 is essentially a box containing a - system of deflectors. At the front of the box is a sample - window 12, also termed a nozzle on account of its conical shape. Above the nozzle 12 is a sample holder 14 that is shown in Figure 1 in its retracted or pulled out position.
When a granular sample is to be analysed, it is placed in - the sample holder 14 and the latter is then pushed in.
On its opposite sides, the optical relay has two - openings of which only the opening 16 is seen in Figure 2. A - similar opening is formed on the opposite side of the relay 10. The openings line up with the source and detection - windows of the IR spectrometer.
When the sample holder 14 is pulled out, the IR radiation entering from the source window is deflected in a horizontal plane (as will be described in greater detail below by reference to Figure 2A) to emerge from the nozzle 12. There it is reflected by the sample and the reflected radiation is once again deflected in a horizontal plane to - leave the optical relay through the opening 16 and enter the detection window of the spectrometer. = When the sample holder is pushed in, the IR radiation entering from the source window is deflected in a vertical plane (as will be described in greater detail below by reference to Figures 2B and 3) to fall on the sample resting on the sample holder 14 within the optical relay. The radiation reflected by the sample is once again deflected in - 6 - a vertical plane to leave the optical relay through the opening 16 and enter the detection window of the spectrometer.
References herein to deflection of IR radiation are intended to include both reflection and refraction.
Furthermore, reflection may either occur at a silvered mirror or at the surface of a prism by total internal reflection.
In the preferred embodiment of the invention, the path followed by the radiation through the optical relay 10 is determined by whether the sample holder 14 is pushed in or pulled out. A carrier 20 is mounted within the optical relay 10 which supports four movable deflectors 22, 24, 26 and 28.
All the remaining deflectors within the optical relay 10 are stationary.
The deflectors 22 and 24 deflect the IR radiation in a horizontal plane as shown in Figure 2A. IR radiation entering from the left in Figure 2 from the source window of the spectrometer is deflected forwards by the deflector 22 onto a concave mirror 30. This mirror 30 focuses the radiation, which is deflected by a further stationary deflector 32 onto the sample arranged at the sample window 12.
The radiation reflected by the sample at the sample window 12 follows a path which is a mirror image of that followed by the incident radiation, that is to say it is reflected by a stationary deflector 34 onto a concave mirror 36 and then by way of the second deflector 24 supported on the movable carrier 20 towards the detection window of the spectrometer.
When a granular sample is to be analysed, it is placed on the sample holder 14 which is then pushed into the - 7 optical relay 10. The movement of the sample holder 14 is accompanied by a movement of the carrier 20 to the position shown in Figures 2B and 3. The deflector 26 on the carrier this time deflects the incident radiation in a vertical plane so that the reflected rays are normal to the plane of Figure 2B. As shown in Figure 3, the IR radiation is then focussed by a concave reflector 40 onto the sample supported on the sample holder 14. The radiation scattered by reflection from the surface of the granular sample is lo reflected by the concave mirror 40 on to the second deflector 28 supported on the movable carrier 20 which in turn directs the radiation towards the detection window of the spectrometer.
].5 It is to be preferred for the detection window not to receive IR radiation directly from the source radiation. To this end, in the illustrated embodiment of the invention, a barrier 42 is positioned above the sample holder and a further barrier, shown schematically at 44 in Figure 2A and JO 2B, is arranged on the movable carrier 20 between the deflectors of each pair 22, 24 and 26, 28. : - 8
Claims (6)
1. An optical relay for an IR spectrometer comprising a housing to be located between the source and detection windows of a spectrometer, the relay comprising a sample window against which a sample may be placed for analysis by the spectrometer and a sample holder for introducing a sample into the housing for analysis by the spectrometer, wherein two systems of deflectors are arranged within the lo housing for selectively deflecting the IR radiation of the spectrometer to analyse a sample placed against the sample window or a sample introduced into the housing by means of the sample holder.
2. An optical relay as claimed in claim 1, wherein the sample window is positioned forward of the line connecting the source and detection windows and the IR radiation is deflected in a horizontal plane to and from the sample window, whereas the sample holder is arranged above the line connecting the source and detection windows and the IR radiation is deflected in a vertical plane to and from the sample in the sample holder.
3. An optical relay as claimed in claim 1 or 2, wherein the optical relay comprises deflectors that are movable in synchronism with the sample holder so that the radiation light path through the optical relay is selected automatically in dependence upon whether the sample holder is pushed in or pulled out.
4. An optical relay as claimed in any preceding claim, wherein at least one barrier is provided to prevent IR radiation from the source window of the spectrometer from reaching the detection window without being reflected by the sample to be analyzed. - 9
5. An optical relay as claimed in any preceding claim wherein at least some of the deflectors are mirrors.
6. An optical relay constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0312751A GB2402493B (en) | 2003-06-04 | 2003-06-04 | Plastics identification |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0312751A GB2402493B (en) | 2003-06-04 | 2003-06-04 | Plastics identification |
Publications (3)
Publication Number | Publication Date |
---|---|
GB0312751D0 GB0312751D0 (en) | 2003-07-09 |
GB2402493A true GB2402493A (en) | 2004-12-08 |
GB2402493B GB2402493B (en) | 2006-06-14 |
Family
ID=9959255
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB0312751A Expired - Fee Related GB2402493B (en) | 2003-06-04 | 2003-06-04 | Plastics identification |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2402493B (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4479058A (en) * | 1981-12-02 | 1984-10-23 | Bruker Analytische Messtechnik Gmbh | Auxiliary unit for carrying out reflection measurements using an IR spectrometer |
US4594509A (en) * | 1983-01-31 | 1986-06-10 | Bruker Analytische Messtechnik Gmbh | Infrared spectrometer |
US5048970A (en) * | 1990-06-29 | 1991-09-17 | Nicolas J. Harrick | Optical attachment for variable angle reflection spectroscopy |
US5499095A (en) * | 1992-10-02 | 1996-03-12 | Bruker Analytische Mebtechnik Gmbh | Fourier spectrometer with exchangeable entrance and exit ports allowing for both internal and external radiation sources |
WO2001067037A1 (en) * | 2000-03-08 | 2001-09-13 | Thermo Nicolet Corporation | Multifunctional fourier transform infrared spectrometer system |
-
2003
- 2003-06-04 GB GB0312751A patent/GB2402493B/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4479058A (en) * | 1981-12-02 | 1984-10-23 | Bruker Analytische Messtechnik Gmbh | Auxiliary unit for carrying out reflection measurements using an IR spectrometer |
US4594509A (en) * | 1983-01-31 | 1986-06-10 | Bruker Analytische Messtechnik Gmbh | Infrared spectrometer |
US5048970A (en) * | 1990-06-29 | 1991-09-17 | Nicolas J. Harrick | Optical attachment for variable angle reflection spectroscopy |
US5499095A (en) * | 1992-10-02 | 1996-03-12 | Bruker Analytische Mebtechnik Gmbh | Fourier spectrometer with exchangeable entrance and exit ports allowing for both internal and external radiation sources |
WO2001067037A1 (en) * | 2000-03-08 | 2001-09-13 | Thermo Nicolet Corporation | Multifunctional fourier transform infrared spectrometer system |
Also Published As
Publication number | Publication date |
---|---|
GB0312751D0 (en) | 2003-07-09 |
GB2402493B (en) | 2006-06-14 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
746 | Register noted 'licences of right' (sect. 46/1977) |
Effective date: 20090223 |
|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20180604 |