GB2209597A - A method of contactless temperature measurement - Google Patents
A method of contactless temperature measurement Download PDFInfo
- Publication number
- GB2209597A GB2209597A GB8820871A GB8820871A GB2209597A GB 2209597 A GB2209597 A GB 2209597A GB 8820871 A GB8820871 A GB 8820871A GB 8820871 A GB8820871 A GB 8820871A GB 2209597 A GB2209597 A GB 2209597A
- Authority
- GB
- United Kingdom
- Prior art keywords
- emission
- degree
- temperature
- materials
- measurement
- 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
- 238000000034 method Methods 0.000 title claims description 11
- 238000009529 body temperature measurement Methods 0.000 title claims description 8
- 239000000463 material Substances 0.000 claims description 25
- 230000003595 spectral effect Effects 0.000 claims description 20
- 238000010521 absorption reaction Methods 0.000 claims description 17
- 239000004033 plastic Substances 0.000 claims description 13
- 229920003023 plastic Polymers 0.000 claims description 13
- 230000005855 radiation Effects 0.000 claims description 7
- 239000011521 glass Substances 0.000 claims description 6
- 238000005259 measurement Methods 0.000 description 12
- 230000001419 dependent effect Effects 0.000 description 2
- 238000004616 Pyrometry Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000012780 transparent material Substances 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
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/60—Radiation pyrometry, e.g. infrared or optical thermometry using determination of colour temperature
- G01J5/602—Radiation pyrometry, e.g. infrared or optical thermometry using determination of colour temperature using selective, monochromatic or bandpass filtering
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Radiation Pyrometers (AREA)
Description
2209597
DESCRIPTION
A METHOD OF CONTACTLESS TEMPERATURE MEASUREMENT, WHICH IS INDEPENDENT OF THE DEGREE OF EMISSION, OF MATERIALS HAVING PRONOUNCED ABSORPTION BANDS.
The invention is concerned with a method of contactless temperature measurement in process and industrial measurement technology of materials having pronounced absorption bands, such as plastics materials and glass.
Known solutions for contactless temperature measurement based on radiation pyrometry have t-he basic disadvantage that the degree of emission of the test object surface must be known. The degree of emission of a non-black-radiating material to be measured is dependent on the wavelength of the test object radiation and on the temperature of the material to be measured itself and, in the case of infrared-transparent materials, it is also dependent on the thickness of the material to be measured. In order to be able to take these dependencies of the degree of emission into account in the measurement result, known pyrometers have devices for correcting the degree of emission, such as, for example, adjusters or computers.
A known way of eliminating the influence of the degree of emission on the measurement result is to select special, particularly suitable spectral ranges.
-2A wide variety of pyrometers are known for measuring a particular plastics material, wherein measurement is carried out with an adjusted degree of emission equal to 1. Given correct selection of the spectral range, measurements are carried out at points of the infrared band having the highest energy supply, that is, given a pronounced absorption band.
Typical absorption bands of different plastics materials are known at 3. 43pm, 3.45pm, 6.8pm, 7.9pm, 7.95pm and 8.05pm, wherein one absorption band can be detected by one single-channel pyrometer, respectively. The advantage of measuring with a pronounced absorption band is to be found above all in the fact that the radiation reflected or transmitted in the direction of the pyrometer, given degrees of emission of less than 1, plays a subordinate role. It is disadvantageous, however, that it is necessary to have precise knowledge of the absorption band of the plastics material being measured in order to select a particular type of plastics pyrometer. If the wrong selection is made, this can result in a large measurement error.
Furthermore, multiple-channel pyrometers are known from DD-PS 219 571 and US-PS 39 22 550, which operate under the precondition that the material to be measured is picked up as a grey-body radiator. This precondition is however, not met in low temperature ranges generally 1 1 t and in plastics materials in particular, since they show a strong non- linear dependency of the degree of emission on the wavelength. Such multiple-channel pyrometers are thus not suitable for measuring plastics materials or glass or for a low-temperature range.
More recently, multiple-channel pyrometers are known from DE-OS 36 11 567 and DE-OS 36 11 634, which must be "adapted" to the special substances to be measured, wherein a microcomputer can be used. These multiple-channel pyrometers are very expensive both in terms of technical expertise as well as structurally, and must still be prepared for use by way of a contact measurement. Such multiple-channel pyrometers are only advantageous given a wide range of use. They are far too expensive, however, for users with special measurement tasks such as the measurement of plastics materials or glass.
It is an object of the invention to provide a method of contactless temperature measurement, which is independent of the degree of emission, of materials having pronounced absorption bands, such as plastics materials or glass, which overcomes the problems of known techniques described above.
In accordance with the present invention, a degree of emission equal to 1 is assumed for each spectral -4range to be evaluated, an object temperature is determined and the highest object temperature determined is output as the true object temperature.
The spectral ranges to be evaluated are selected such that, for example, at least one absorption band is covered for almost all types of plastics materials. Under the precondition that the background radiation reflected or transmitted in each spectral range is smaller than or at the'most equal to the radiation emitted by the test object, given a degree of emission equal to 1, an object temperature is determined for each spectral range having a degree of emission equal to 1. The highest object temperature determined is also the true object temperature, since this spectral range has the most pronounced absorption band.
It is thus a feature of the invention to provide a method of contactless temperature measurement, which is independent of the degree of emission, of materials having pronounced absorption bands, wherein measurements are made in several spectral ranges. As a result of measurement being carried out in several spectral ranges, the position of the absorption bands of the material being measured does not have to be known, so that the degree of emission does not have to be adjusted separately or taken into account in the measurement result. A further advantage of the method according to I.
:k -1 the invention is that material analysis is possible within a limited scope.
The invention is described further hereinafter with reference to the use of the present method for the contactless temperature measurement of plastics materials by means of a multiple-channel pyrometer.
In order to carry out the method according to the invention, four narrowband spectral ranges of wavelengths 3.43pm, 6.8pm, 7.9)im and 8.05Y m are fixed as the spectral ranges of the test object radiation to be selected. In these four spectral ranges, almost all types of plastics materials have a pronounced absorption band. In a multiple-channel pyrometer, these four spectral ranges are realised, for example, by way of four narrow- band filters, which are mounted on a filter wheel. The filter wheel replaces the chopper in rotating light pyrometers. If a degree of emission equal to 1 is laid down for each of these four spectral ranges and a corresponding object temperature is determined in each case, the highest object temperature determined is the true object temperature. The reason for this is that the absorption band is most pronounced and hence the degree of spectral emission is closest to the previously adopted value of 1 for the highest object temperature determined.
In the same way, when the spectral range which corresponds to the highest object temperature determined is output, it is possible to identify the material within certain limits. The highest object temperature in the four spectral ranges can be determined, for example, using an analogue computing circuit or a microcomputer as a component of the multiplechannel pyrometer. When filters are used corresponding to the absorption bands of other materials, for example glass having absorption bands in the range 4.5m... 5.5yM, the invention can also be used for this.
P
Claims (1)
- CLAIM1. A method of contactless temperature measurement, which is independent of the degree of emission, of materials having pronounced absorption bands, such as plastics materials or glass, by means of a multiplechannel pyrometer, wherein radiation from the test object is evaluated in at least two narrow-band spectral ranges, and a degree of emission equal to 1 is assumed for each spectral range to be evaluated, an object temperature being determined for each spectral range to be evaluated and the highest object temperature determined being output as the true object temperature.Published 1988 at The Patent Office. State House. 6671 High Holborn. London WC1R 4TP- Further copies may be obtained from The Patent Office,
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DD30670387 | 1987-09-07 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8820871D0 GB8820871D0 (en) | 1988-10-05 |
| GB2209597A true GB2209597A (en) | 1989-05-17 |
| GB2209597B GB2209597B (en) | 1991-05-08 |
Family
ID=5592085
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8820871A Expired - Fee Related GB2209597B (en) | 1987-09-07 | 1988-09-06 | A method of contactless temperature measurement, which is independent of the degree of emission, of materials having pronounced absorption bands |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE3821476A1 (en) |
| GB (1) | GB2209597B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2663740B1 (en) * | 1990-06-21 | 1992-09-11 | Commissariat Energie Atomique | PROCESS FOR EXPLOITING SIGNALS PROVIDED BY AN OPTICAL PYROMETER, PARTICULARLY FOR MEASURING ACCURATELY THE TEMPERATURE OF MOVING BODY AND AT RAPIDLY EVOLUTIVE TEMPERATURE. |
| FR2684762A1 (en) * | 1991-12-06 | 1993-06-11 | Mercade Francois | TEMPERATURE MEASURING DEVICE AND USE THEREOF. |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3477963D1 (en) * | 1983-06-16 | 1989-06-01 | Deutsche Forsch Luft Raumfahrt | Method for the contactless radiation measurement of the temperature of an object independent of its emissivity, and device for carrying out this method |
| JPS60165525A (en) * | 1984-02-08 | 1985-08-28 | Ulvac Corp | Emission temperature measuring method |
| US4659234A (en) * | 1984-06-18 | 1987-04-21 | Aluminum Company Of America | Emissivity error correcting method for radiation thermometer |
-
1988
- 1988-06-25 DE DE19883821476 patent/DE3821476A1/en active Granted
- 1988-09-06 GB GB8820871A patent/GB2209597B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE3821476A1 (en) | 1989-03-16 |
| GB2209597B (en) | 1991-05-08 |
| DE3821476C2 (en) | 1990-12-06 |
| GB8820871D0 (en) | 1988-10-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| 732 | Registration of transactions, instruments or events in the register (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950906 |