JPH07181135A - Equipment and method for enabling analysis of fluidity material - Google Patents

Abstract

PURPOSE: To nondestructively analyze a fluid material in a transport system by heating or cooling a part of the surface of the fluid material for generating a transient temperature difference between a thin surface layer part and another part positioned sufficiently thereunder or at a deep position. CONSTITUTION: A fluid material 10 flows in a transport system 12 across an infrared transmission part (window) 14. Furthermore, an energy source 16 applies heating energy or cooling energy to the material 10, thereby heating or cooling the thin surface layer of the material 10 adjacent to the window. Also, when the heating energy is applied to the thin layer via the window 14, an emission spectrum can be observed, while emission energy can be observed, when the cooling energy is applied. in this case, a condensing optical system can be used for focusing an infrared ray emitted from the material 10 on a spectral meter/ detection system 18, and this system 18 generates electrical signals as a function of the wave number of an emitted radiation. Also, a computer system 20 processes the signals from the system 18, so as to obtain required chemical or physical information.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to spectral analysis of materials, and more particularly to non-contact, remote spectral analysis of bulk fluid materials based on the transient thermal infrared spectrum from the material. Flowable materials include liquids, gases, usually solid substances, but melts heated above the melting temperature, powders and pellets contained in a transport system such as a container or conduit.

There are various types of currently known analytical methods for collecting information about materials. Spectral methods are well known and are common methods of analyzing materials.
There are also many types of this spectral method, and these methods can be applied to certain kinds of analysis and measurement and have advantages and disadvantages.

There is a current need to improve the ability to analyze materials, especially when it is desired to analyze the material quickly, efficiently and accurately. In addition, there is a practical desire to perform such analysis during the process. That is, there is a desire to go online directly during the manufacture or processing of the material.

For many materials, there are various generally conventional spectral methods for analyzing the constituents and other properties of these materials. As some of these methods,
There are infrared transmission spectroscopy, diffuse reflection spectroscopy, photoacoustic spectroscopy and emission spectroscopy. While these methods generally give satisfactory results, they have drawbacks because they require selective and sometimes destructive sampling of the material. There are also materials (eg, coal) that require grinding or grinding. In addition, analytical materials often have to be sent to a remote test room, which requires time and money for testing and equipment before results can be obtained.

Many of the above currently used methods also
There is no great flexibility in use. Although some methods do not require destructive sampling, such as grinding or milling, these methods cannot be used for materials thicker than the minimum thickness or materials of varying thickness. Conventional transmission or emission spectroscopy has the problem that many optical thicknesses of the material are too thick to measure accurately and reliably. When a thick sample is heated, the thick layer of the sample only emits strongly at the preferred wavelength but weakly at other wavelengths. However, since the surface layer of the thick sample preferentially absorbs a specific wavelength, the strong emission light of the thick layer having a preferable wavelength is largely attenuated before being separated from the sample. Such a process is called self-absorption. Due to self-absorption in optically thick samples, large truncations occur in the strong spectral bands, approximating the blackbody radiation spectrum of optically thick materials heated to uniform temperature, and the spectral structure of the analyzed material. An emission spectrum containing almost no characteristics of is generated.

Until now, attempts have been made to solve this self-absorption problem by making the sample material thinner. Routine measurements of high quality spectra of free-standing films and thin layers on low emitting substrates require selective sampling and processing of the material to be analyzed.

Other types of spectral analysis methods, such as photoacoustic and reflectance spectroscopy, which are less susceptible to optical density problems, have the disadvantage that they are not easily implemented for moving material streams. . Therefore, there is a practical need in the art for devices and methods that have the flexibility to be used for both moving and stationary materials and materials that may have significant optical densities.

[0008] In US Pat. Nos. 5,070,242 and 5,075,552, the temperature of the thin surface layer of the sample material is lower or higher than the overall temperature of the sample material. Transient infrared spectroscopy is applied to the material that has a temperature gradient on its surface. When the surface is heated, it emits infrared light independent of the total sample material. Since the surface layer is thin, its spectrum is less prone to self-absorption phenomena obscuring the emission spectrum of optically thick materials, which is characteristic of the molecular composition of the sample material. Correctly detected. Similarly, when the surface is cooled, the surface layer acts as a thin transmission sample, and the transmission spectrum detected is spontaneously emitted from the uncooled whole of the sample material and the infrared light passing through the thin surface layer. It is applied over light and is characteristic of the molecular composition of the sample material. However, the above US patents
It generally relates to materials that are not contained within a transportation system, such as containers and conduits.

Accordingly, it is a primary object of the present invention to ameliorate or solve the shortcomings and problems of the art relating to free-flowing encapsulated materials.

Another object of the present invention is to provide a thermal transient infrared transmission spectrum analyzer and method that can be utilized with flowable encapsulated materials.

Another object of the present invention is an apparatus and method for the analysis of a flowable material contained within a transportation system, such as a container, which heats or cools a thin surface layer portion of the material. To produce a transient temperature difference between the thin surface layer portion and the material portion sufficiently below the material's black body thermal infrared emission spectrum to change the material's thermal infrared emission spectrum. An apparatus and method is provided that comprises detecting an altered thermal infrared emission spectrum of a material through an infrared transmissive portion of a transport system without sufficient self-absorption of the emitted infrared radiation by the material itself into the thermal infrared emission spectrum.

Another object of the present invention is to provide an apparatus and method as described above, which can perform detection and analysis generally without contact with the material.

Yet another object of the present invention is to provide an apparatus and method as described above which can be practiced remote from the material to be analyzed.

Yet another object of the present invention is to provide an apparatus and method as described above which can reveal the molecular composition of a material and the various physical and chemical properties of the material related to the molecular composition.

Another object of the present invention is to provide the above apparatus and method which can be directly used in a manufacturing line or a processing line for handling materials.

Yet another object of the present invention is to provide such a device and method that is non-destructive to the material being analyzed.

Yet another object of the present invention is to provide an apparatus and method as described above that can be utilized to analyze either large or small samples of material in a laboratory environment.

Yet another object of the present invention is to provide such an apparatus and method which can be utilized with optically dense materials.

Yet another object of the present invention is to provide an apparatus and method as described above which overcomes the spectral analysis problems caused by the self-absorption of radiation emitted from the material to be analyzed.

Yet another object of the present invention is to provide such an apparatus and method which can be used continuously and non-destructively with unknown quantities of flowable material.

Another object of the present invention is to provide such an apparatus and method that can be utilized directly in the process for unknown quantities of moving material.

Yet another object of the present invention is to provide such an apparatus and method which is economical, efficient and reliable.

Another object of the present invention is to provide such an apparatus and method that can be operated under conditions of extreme and varying processing environments for materials or in the environment of a laboratory.

Yet another object of the present invention is to provide such an apparatus and method which can be combined with a computer system to obtain information about a material that is useful in processing, controlling and analyzing the material.

The present invention provides an apparatus and method for nondestructively analyzing flowable materials contained within a transportation system by infrared spectroscopy. A temperature difference is transiently generated between a thin surface layer portion of the material and a portion of the material that is located below or deep enough to alter the material's black infrared thermal infrared emission spectrum. That is, by heating or cooling a portion of the surface of the material, a thin surface layer portion and a material located below or deep enough to change the thermal infrared emission spectrum of the material from the black body thermal infrared emission spectrum of the material. A transient temperature difference is generated between the parts. Since this temperature difference is transmitted to the lower part of the material, the changed thermal infrared rays before the temperature difference is transmitted to the lower part of the material to the extent that the self-absorption of the infrared radiation emitted by the material itself does not disappear in the changed thermal infrared emission spectrum The changed thermal infrared emission spectrum of the material is detected while the emission spectrum does not have sufficient self-absorption of the infrared radiation emitted by the material itself. This altered thermal infrared emission spectrum is detected as an infrared spectrum, for example by a spectrometer, through an infrared transparent part of the transport system, for example through a window in a conduit. This spectrum contains information about the molecular composition of the material. Based on the changed thermal infrared emission spectrum detected thereafter,
The characteristics regarding the molecular composition of the material can be determined.

In accordance with the present invention, the heating or cooling source applies energy to a portion of the surface of the material to cause transient heating or cooling of the thin surface layer of the material. When heating a thin surface layer of a material, the thermal infrared emission from the thin layer is detected through the transparent part of the transport system, which is analyzed by a detector and the Kirchhoff's law is used to determine the infrared absorption spectrum of the material. obtain. When cooling a thin surface layer of material, the infrared emission from the hotter material below the cooled layer is superimposed on the transmission spectrum of the cooled layer, resulting in a modified infrared emission spectrum. It is detected through the transparent part of the transport system. Since all of the material in the lower than the cooling layer having a whole ie depth l of the material is in a uniform temperature, across i.e. the lower portion of the material emits blackbody spectrum of the temperature T _H. If the cooling surface layer is optically thin so as to satisfy l <1 / β (where β is the absorptivity), the surface layer has a negligible amount of infrared light compared to the amount of infrared light that passes through this surface layer from the entire material. It only releases. The reason for this is both the thin surface and the emission intensity being proportional to T ⁴ . Therefore, the cooled surface layer absorbs infrared rays emitted from the entire material, and thus the changed thermal infrared rays are detected. Therefore, the cooling layer behaves like a sample of thickness l when placed in an infrared spectrometer where the cryogenic source is T _H , and the emitted infrared radiation reaching the spectrometer is of an optically thin cooled layer. It becomes a transmission spectrum. Hereinafter, this spectrum is referred to as a "transmission spectrum".

According to the invention, this transmission spectrum, ie the modified thermal infrared emission spectrum, is carried out by a spectrometer and a detector. In the preferred embodiment, this detector may comprise, for example, a cooled HgCdTe infrared detector. This changed thermal infrared emission spectrum is applied while the self-absorption of the emitted infrared light by the material itself is insufficient.By cooling the thin surface layer portion, a temperature is transiently generated in the thin surface layer portion. The detector operates to detect an altered thermal infrared emission spectrum of the material that has changed from the emission spectrum. That is, the detection is performed before the temperature difference is transmitted to the lower portion or the deep portion of the material to the extent that the self-absorption of the emitted infrared light by the material itself is not sufficiently eliminated in the changed thermal infrared emission spectrum. Upon such detection, the altered thermal infrared spectrum detected is characteristic of the molecular composition of the material.

According to the invention, the detector may be controlled by a controller and / or a processor with suitable software for deriving different features from the detected predetermined spectrum of infrared radiation from the material. The output may be generated to a control device that includes it. Further, such a controller or processor may include suitable computer memory, storage, and printer or graphics components.

The above and other objects, features and advantages of the present invention will be apparent with reference to the accompanying drawings.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Reference will now be made to the accompanying drawings. In the drawings, the same reference numerals indicate the same parts. FIG. 1 shows an embodiment of the present invention. In this embodiment, the fluid material 10 to be analyzed in the form of a liquid or powder slurry is transferred to the transportation system 12,
Thermally thin infrared transparent portion 1 of a container or conduit, for example
4, flowing in the transport system 12 through a window located in the wall of the container or conduit, for example. Arrows indicate the direction of material flow. Energy source 16 applies heating or cooling energy to the fluent material to heat or cool a thin surface layer of material adjacent the window. When applying heating energy, the energy source 16 can consist of a hot gas jet or laser arranged to pulse or continuously apply energy to the material through the window 14. When applying cooling energy, the energy source 16 is
It may consist of a cooling gas jet arranged to apply energy to the material through. A spectrometer / detection system 18 having a field of view (indicated by a dotted line) so that the emission spectrum can be observed when heat energy is applied to the thin layer through the window, and the transmission energy can be observed when cooling energy is applied is arranged relative to the window. ing. The flow of sample prevents the thermally altered thin surface layer in contact with the window 14 from growing so thick that its infrared transmission does not prevent the collection of useful spectra.

As known in the art, collection optics may be utilized to focus the infrared radiation emitted from the fluent material 10 onto the spectrometer / detection system 18. The detection system 18 produces an electrical signal as a function of the wavenumber of the emitted radiation. Computer system 20 processes the signals from system 18 to obtain the necessary chemical or physical information. Computer system 20 is coupled to a display 22 for displaying the desired information including the detected spectrum, for example by a display screen or printer. The computer system can also be coupled to a controller 24, for controlling the calculation of energy and / or process parameters, for example.

FIG. 2 shows the spectrum of 2-propanol (normal rubbing alcohol) obtained by the example corresponding to FIG. The side surface of the container containing 2-propanol as the liquid to be analyzed is made of polyethylene and is extremely thin (12
μm) Heat was applied to the outer surface of the window using a hot gas jet. Polyethylene has almost no infrared spectrum of its own, its influence on the observation spectrum is small due to the thinness of the window, and heat applied to the outside can be easily transferred to the liquid in the container.

The bottom two spectra (a) and (b) of FIG. 2 were obtained according to the embodiment of FIG. 1, the spectrum (a) being obtained with a moving or flowing alcohol. And the spectrum (b) was obtained with the liquid in the resting state. The upper spectrum (c) is displayed for comparison purposes and was previously obtained by passing infrared light through a very thin film of alcohol at rest. This spectrum shows the structure that the spectrographer expects to identify the liquid. The almost flat spectrum (d) was obtained by heating all of the alcohol in the container. 2-in this spectrum
The few structures designated as propanol are the result of self-absorption. In contrast, the lower two spectra (a) and (b) have the same structure as the upper spectrum (c), but the stronger peaks are truncated at approximately the same height. . Again, this is due to self-absorption, but in these spectra, the present invention reduces the self-absorption to such a level that analytically effective structures occur in the spectrum. In the non-flowing sample, the thickness of the heated layer of alcohol that contributes to the spectrum is controlled by the rate of thermal diffusion and convection in the alcohol. When the sample is flowing,
The heated layer is actively thinned by motion faster than convection. As a result, the spectrum of the moving liquid is less susceptible to self-absorption and matches the absorption spectrum of the top well. The polyethylene window is 817 cm
Peak and part of the ^in-1 is in effect in some spectrum in that is causing the peak at 1467cm ~ ^1.
The rest of the structure of the detected spectrum is due to alcohol, and the weaker features that are only noticed in the upper spectrum are stronger in the lower two spectra.
The reason for this is that these weak features are not originally strong, but the strong features are relatively weakened by self-absorption.

It should be noted that it is difficult to provide a window as thin as the window used above in practical applications. Since windows are usually quite thick,
A heat or cold source will be provided inside the window.
FIG. 3 shows that the fluid flows in the direction of the arrow, ie, passes through a thick infrared transmissive window 14 'having a convex surface 15 that projects into the flow of material to form a lens that makes better contact with the material and helps collect infrared signals. An example is shown. Heat is applied by a tantalum ribbon 16 'extending perpendicular to the flow direction at the upstream edge of the field of view (indicated by the dotted line) of the spectrometer of the spectrometer / detection system 18 and the inner surface of the window 14' of the transport system 12. Held against. Naturally, various variations of this basic method are possible. The heating element may consist of a thin film deposited directly on the window in or outside the field of view of the spectrometer. The window may also be fitted with a heat exchanger comprised of small diameter, thin walled tubes that carry hot or cold liquids. Various other small-scale refrigerators or cooling liquids (eg, thermoelectric, Joule-Thomson effect element) are also possible. A heat source or a low temperature source may be provided outside the window instead of inside.

If the material to be analyzed consists of pellets or other particles, it is also possible to use heating or cooling jets. As shown in FIG. 4, pellets 10 'and the like flowing in the direction of the arrow in the pneumatic transportation tube 12' as often used in the industry will have considerable momentum. In such a sharp turning section in the tube, the pellet 1
0'is pressed to the outside of the wall. The window 14 "is positioned as shown in FIG. 4 so that the pellet is pressed against the window and a moderate jet of hot or cold gas from the energy source is added to the upstream edge of the window to cause thermal transients. The spectrometer / detection system 18 and other system components operate as described above, and such an apparatus can also be used with two-phase sample materials such as slurries.

As long as the window of the transport system that passes through the infrared spectrum for detection is also capable of passing through the laser beam and allows heating of the material contained within the transport system, the heating energy source is described in the above-referenced US patents. A laser is enough.

The spectrometer / detection system operates to substantially detect only transiently altered heat emission of infrared radiation passing through its field of view in the case of flowing material,
In the case of stationary materials, it is controlled, for example, to detect transiently changed heat emission of infrared radiation for a certain period of time.

As also mentioned in the above-referenced US patents, the computer system processes the signals detected and measured by the spectrometer / detector system to provide any number of different tasks such as process control, quality control, analytical chemistry. Or it makes it possible to obtain molecular information or other physical and chemical information by the correlation techniques required for non-destructive evaluation. The computer system also includes suitable computer software and complementary data for obtaining different material properties from the infrared emission spectrum. In addition, the computer system can use appropriate software, displays, complementary data and servo systems to make decisions based on the infrared spectrum, command and execute, for example, process control. .

Although some embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and some modifications and variations can be made by those skilled in the art. Is. Therefore, the invention is not to be limited to the details of the embodiments set forth herein, but rather should be understood to include all modifications and variations covered by the claims.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention, including a partial cross section.

FIG. 2 is a graph showing an observed spectrum obtained in the example shown in FIG. 2 of the present invention and a conventionally obtained spectrum.

FIG. 3 is a block diagram showing a configuration of another embodiment of the present invention, including a partial cross section.

FIG. 4 is a block diagram including a partial cross-section showing a configuration of still another embodiment of the present invention.

[Explanation of symbols]

 10 Fluid Material 12 Transport System 14 Transmission Part 16 Energy Source 18 Spectrometer / Detection System 20 Computer System 22 Display 24 Controller

Claims (26)

[Claims] 1. A method for enabling analysis of a flowable material contained within a transportation system, the thermal infrared emission of a material from a thin surface layer portion of the material and a black body thermal infrared emission spectrum of the material. A modified thermal infrared emission spectrum is created so that a transient temperature difference is generated between the material and a portion of the material that is sufficiently below to change the spectrum, and the detected modified thermal infrared emission spectrum is characteristic of the molecular composition of the material. In addition, the thermal infrared emission spectrum changed before the temperature difference was transmitted to the lower part of the material to the extent that the self-absorption of the infrared radiation by the material itself did not disappear sufficiently. A method comprising detecting a modified thermal infrared emission spectrum of a material through an infrared transparent portion of a transport system. 2. The process for transiently producing a temperature difference causes transient heating of a thin surface layer portion of the material to enable transient heat release of infrared radiation from the thin surface layer portion. 2. Applying energy to a surface area adjacent to the infrared-transmissive portion of the transport system sufficiently.
the method of. 3. The step of transiently producing a temperature difference comprises transient cooling of a thin surface layer portion and infrared radiation emitted from a lower portion of the material below the cooling layer and above the cooling layer. 2. The method of claim 1 comprising applying energy to the surface region of the material adjacent the infrared transparent portion of the transport system sufficiently to cause overlap of the transmission spectra of the cooling layers of. 4. The step of detecting through the infrared transmissive portion of the transport system comprises substantially detecting only the transiently altered thermal infrared emission spectrum with substantially no self-absorption of the emitted infrared radiation by the material itself. Item 1 method. 5. The step of applying energy to the surface area of the material comprises applying one of thermal energy and cold energy to the surface area of the material adjacent to the infrared transparent portion of the transport system in a pulsed or continuous manner. Method 1. 6. An infrared transmissive portion of a transport system wherein the step of applying energy to the surface area of the material is also a thermally transmissive portion that allows for direct application of energy to the surface area of the material or transmission of the applied energy. The method of claim 5 comprising applying energy indirectly through the. 7. The method of claim 1, wherein the material is one of a flowing material and a stationary material. 8. The method of claim 7, wherein the flowable material is one of a liquid, a gas, a powder, a pellet and a melt. 9. The transport system comprises an infrared transparent portion disposed in the wall thereof as a window, comprising at least one of a container for flowable material and a conduit, wherein the detecting step comprises at least one of the windows. The method of claim 1 comprising utilizing a detector having a field of view to detect the transiently altered thermal infrared emission spectrum of the material transmitted through the window. 10. The method of claim 9, wherein the detecting step comprises providing a convex surface contacting the fluent material on a portion of the window facing the fluent material. 11. The method of claim 9 wherein the material is a flowing material and the moving material is positioned within the wall of the transport system such that the window moves parallel to a range of windows. 12. The material is a moving material and the window is positioned within the wall of the transport system such that the moving material impinges upon it and extends transversely to the initial direction of movement of the moving material to deflect from the window. The method of claim 9, wherein 13. The method of claim 1, further comprising the step of characterizing the flowable material with respect to molecular composition according to the detected transiently altered heat emission spectra. 14. An apparatus for enabling analysis of a flowable material contained within a transport system, the infrared transmissive member being provided within a wall of the transport system; and a thin surface layer portion of the material. A means for producing a transient temperature difference between the black body thermal infrared emission spectrum of the material and a portion of the material sufficiently below to change the thermal infrared emission spectrum of the material; and the detected altered thermal infrared emission. Thermal infrared radiation changed before the temperature difference propagates to the lower part of the material to the extent that the self-absorption of the emitted infrared radiation by the material itself does not sufficiently disappear in the changed thermal infrared emission spectrum so that the spectrum shows the characteristics of the molecular composition of the material Modified thermal infrared emission of a material through the infrared-transmissive part of a transport system, with the emission spectrum not being sufficiently self-absorption of the emitted infrared A device comprising means for detecting a spectrum. 15. A means for transiently producing a temperature difference causes transient heating of a thin surface layer portion of the material to allow transient heat release of infrared radiation from the thin surface layer portion. 15. Means for applying energy to a surface area adjacent to an infrared transparent portion of a transport system sufficiently.
Equipment. 16. The means for transiently producing a temperature difference comprises:
Sufficient transport to cause transient cooling of a portion of the thin surface layer and overlap of the transmission spectrum of the cooling layer with infrared radiation emitted from the lower portion of the material below this cooling layer and above the cooling layer 15. The apparatus of claim 14 including means for applying energy to a surface area of the material adjacent the infrared transparent portion of the system. 17. The means for detecting through the infrared transmissive portion of the transport system includes means for substantially detecting only transiently altered thermal infrared emission spectra with substantially no self-absorption of emitted infrared radiation by the material itself. Item 14. The device according to item 14. 18. The means for applying energy to the surface area of the material comprises means for applying one of thermal energy and cold energy to the surface area of the material adjacent to the infrared transparent portion of the transport system in a pulsed or continuous manner. 14
Equipment. 19. An infrared transmissive portion of a transport system, wherein the means for applying energy to the surface area of the material is also a means for applying energy directly to the surface area of the material or a thermally transmissive portion allowing transmission of the applied energy. 19. A means for indirectly applying energy through
Equipment. 20. The device of claim 14, wherein the material is one of a flowing material and a stationary material. 21. The device of claim 20, wherein the flowable material is one of a liquid, a gas, a powder, a pellet and a melt. 22. The transport system comprises an infrared transparent portion disposed in the wall thereof as a window, comprising at least one of a container for flowable material and a conduit, the detection means being at least one of the windows. 15. The apparatus of claim 14 comprising a detector having a field of view and utilizing the detector to detect a transiently altered thermal infrared emission spectrum of the material transmitted through the window. 23. The method of claim 22, wherein the detector comprises a portion of the window facing the fluent material provided with a convex surface capable of contacting the fluent material. 24. The apparatus of claim 22, wherein the material is a flowing material and the window is located within the wall of the transport system so that the moving material moves parallel to the range of windows. 25. The material is a moving material and the window is positioned in the wall of the transport system such that the moving material impinges and extends laterally in the direction of initial movement of the moving material to deflect from the window. 23. The device of claim 22. 26. The apparatus of claim 14 further comprising means for determining a characteristic of the flowable material with respect to molecular composition according to the detected transiently altered heat emission spectrum.