JP2005127932A - Optical method and instrument for detecting wood preservative - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To nondestructively/noncontactingly determine a wood impregnated/applied with a toxic CCA metal compound or the like out of a large amount of waste woods to separate/sort the CCA-treated wood from the waste woods. <P>SOLUTION: In this optical method/instrument for detecting a wood preservative for the wood, the inspected wood is irradiated with 380 nm-2500 nm of visible light or near-infrared ray, to be spectrally dispersed into light having 964 nm±20 nm of wavelength assigned to the toxic wood preservative (CCA) containing copper, chromium and/or arsenic and light having 922 nm±20 nm of wavelength not assigned to the CCA wood preservative and to be photoreceived, via an optical sensor for receiving reflected light, and the method/instrument is provided with an absorbance calculator for conducting digital signal processing conversion for an absorbance in each of the wavelengths, a computer for computing a secondary differential value of the absorbance, and a computation software for each, conducts the nondestructive/noncontact determination, and outputs a determination result with screen display, an alarm sound or relay contact. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wood preservative detection method and apparatus for detecting a toxic metal compound wood preservative impregnated or coated on wood in a non-contact and non-destructive manner, and an industrial waste treatment plant or a building demolition site Efficiently discovers preservative-treated wood from a large number of waste wood, etc., and sorts waste wood into clean resources and pollutants to help ensure safety during reuse .

According to the waste statistics of 1996, the generation of waste wood in our country is about 47 million m ³ per year, more than 90% without being re-used, have been disposed of by incineration or landfill. Most of the causes are timber generated at the time of demolition and construction of houses, accounting for about 74% of the total waste. Among them, waste wood caused by the dismantling of houses, in particular, is often obtained by impregnating or applying wood preservatives (a toxic wood preservative (CCA) containing copper, chromium, arsenic) to preserve and protect ants. .

  The types of wood preservatives registered in Japanese Industrial Standard JIS K1570 include chromium, copper, arsenic compounds (CCA), phenols, inorganic fluoride compounds (FCAP), and alkylammonium compounds as water-soluble preservatives. (AAC), chromium / copper / zinc compound (CFKZ), copper / alkyl ammonium compound (ACQ), copper / boron / azole compound (CUAZ), boron / alkyl ammonium compound (BAAC), Fatty acid metal salt-based compounds (NCU {Naphthenic acid copper compound} · NZN {Naphthenic acid zinc compound} · VZN {Versatic acid zinc compound}), azole-based compounds (AZP) as other emulsifying preservatives, and Creo as other oily wood preservatives There is a sort oil wood preservative.

  In particular, preservative-treated wood (hereinafter also referred to as “CCA-treated wood”) into which CCA preservatives (chromium, copper, arsenic compound-based wood preservatives) are injected is CCA-treated wood impregnated and coated with toxic heavy metal compounds. Is the representative, and the past usage is overwhelmingly large, which is a major obstacle to promoting the recycling of waste wood.

  When CCA-treated wood is subjected to incineration volume reduction at an industrial waste treatment plant or the like, toxic gas containing arsenic is generated, and incinerated ash contains hexavalent chromium and arsenic which are toxic substances. Further, in the carbonization treatment, which is currently a common treatment method, charcoal products contain high concentrations of copper, chromium and arsenic. In addition, arsenic, chromium, and copper may flow into groundwater from landfills, causing environmental problems.

  Regarding the behavior of the heavy metals contained, Journal of the Wood Society, Vol. 46, no. 6. As shown in (2000p587-595), the behavior of copper, chromium and arsenic during combustion of CCA-treated wood shows that the chromium contained in the wood does not depend on the combustion temperature and remains in incineration ash with a residue rate close to 100%. Remains. Copper and arsenic tend to decrease with an increase in combustion temperature, and the residual rate is 40% to 80%. Particularly, a sample having a higher content of copper, chromium and arsenic decreases. This decrease in the residual rate of arsenic is due to thermal evaporation, and is considered to be diffused into the atmosphere as arsenic gas. Moreover, when carbonizing the CCA-treated wood, it was confirmed that the evaporation of copper and chromium hardly occurs and remains in the charcoal at a high concentration, and arsenic evaporates. From the above, it is necessary to take measures against heavy metals contained when recycling and producing charcoal using CCA-treated wood.

In addition, according to a survey on waste wood chemicals conducted by the Waste Research Foundation, the results of measuring the heavy metal content of CCA-treated wood are as shown in Table 1 below, and the average content of heavy metals is 1053 mg chromium / kg, copper 425 mg / kg, and arsenic 460 mg / kg. Moreover, as a result of conducting a dissolution test from CCA-treated wood, elution was observed at concentrations of chromium 6.2 to 19.2 mg / L, copper 3.8 to 12.2 mg / L, and arsenic 2.8 to 14.6 mg / L. confirmed. In addition, when CCA-treated wood is disposed of in landfill, the elution rate is about 5 to 10% of the content of copper, chromium, and arsenic in powder samples, but it is confirmed that heavy metals may be eluted. Has been confirmed that it may be eluted at a concentration exceeding the standards stipulated by law (judgment standards in the Environmental Agency Notification No. 13 Act (Table 2)). By the way.

  In the future, considering the rebuilding of houses and the recent spread of gardening materials, it is expected that preservative timber, especially timber treated with CCA, will increase and will be generated in large quantities as waste timber and impregnated and coated with CCA preservatives. Development of a preservative-treated wood detection technology and its equipment that enable rapid judgment and separation of non-destructive, non-contact wood is required.

  On top of that, in order to promote the recycling of waste wood, at industrial waste disposal sites and construction demolition sites, toxic materials against wood contaminated with harmful metal compounds such as CCA-treated wood and other waste wood It is necessary to separate and separate all of this, including the parts that may have been injected, and to properly recycle and dispose of them separately. Therefore, it is important to quickly identify and separate non-destructive and non-contact CCA-treated timber, etc., and automation and cost reduction that can be used in the waste wood receiving business, waste processing business and building demolition sites The development of detection techniques that lead to

  Currently, methods for detecting and quantifying wood components and harmful heavy metal compounds (CCA preservatives) impregnated and coated on wood include atomic absorption spectrometry, elemental analysis by spectrophotometry, and compounds by titration The quantification of these is mainly used. As a color reaction by applying a simple reagent of CCA preservative, chromium compound is reacted with diphenylcarbazide solution on chromium and colored reaction with reddish purple complex and atomic absorption method. Copper is converted to diethyldithiocarbamate. The yellow-brown complex formed by reaction with sodium is extracted with N-butyl acetate and the absorbance is measured. Further, there is a method in which arsenic is generated as arsenic hydride, absorbed in a chloroform solution of silver diethyldithiocarbamate, and the absorbance of the resulting red-purple solution is measured.

  In addition, methods for quantitative analysis of wood components using an instrument are also being studied, and examples of such methods include NMR (nuclear magnetic resonance) spectroscopy, FTIR (Fourier transform infrared) spectroscopy, and fluorescence spectroscopy.

  However, in NMR spectroscopy, it is necessary to collect a sample in a sample tube, and there is a disadvantage that analysis time becomes long. In addition, the usual FTIR spectroscopy using the fingerprint region of 650-1600 cm-1 (6,250-15,300 nm) requires sample preparation, and at that time, KBr powder must be mixed and molded. There is.

  In contrast, NIR (near-infrared) spectroscopy has the advantage of being simple because it can directly measure a sample, and can be used for quantification of wood components such as cellulose, lignin, hot water-soluble components, and alkali-soluble components. There are some examples. However, until now, NIR spectroscopy has many problems as analytical methods such as the absorption range of many wood components and the absorption range of water overlapping, and each absorption band becomes broad. There is no example used for evaluation and judgment of wood preservatives. Also, in spectroscopic analysis including NIR, in most cases, changes in light transmission characteristics are measured so as not to depend on the shape or surface state of the sample. However, in order to measure the transmission characteristics, it is necessary to process the inspected wood into a specific shape, and it is difficult to specially measure the contents (hazardous materials) because it requires specialized techniques and is a very expensive method. Met. It was difficult to perform non-destructive and non-contact measurement.

  Therefore, there is a non-destructive and non-contact measurement as a required technique. Currently, fluorescence spectroscopy is used as one of the techniques capable of non-destructive and non-contact sample analysis. However, this method irradiates a sample with specific excitation light, and the light generated thereby has a longer wavelength than the original excitation light, and this light is intended to be detected. There was a problem with it. (For example, when ultraviolet light or visible light is irradiated as excitation light in the fluorescence detection method, only those having a specific structure at the molecular level emit fluorescence. Furthermore, fluorescence by ultraviolet light or visible light has a wide line width. Because there are many cases and problems as general-purpose analyzers, they are mainly used for applied measurement using substances with remarkable fluorescence characteristics in specific fields such as biological, scientific, and medical.)

In addition, the fluorescent X-ray method using X-rays having high energy as excitation light excites electrons in the inner core of the substance, so that the atoms constituting the substance can be identified. However, the general fluorescent X-ray method requires an X-ray tube that is dangerous to handle, and further requires a diffraction grating and a wave height analyzer for spectroscopy, resulting in a large-scale apparatus configuration.

Buildings are often demolished using machines. Wood chips are often minced (mixed waste) and are greatly affected by heat radiation, air, and moisture, including surface contamination. It is very difficult to tell whether wood is preserved in such a state. Even in the case of all manual dismantling, it is difficult to judge whether or not antiseptic treatment has been applied. Therefore, conventional spectroscopic methods using color inspections and large-scale equipment are difficult to identify hazardous waste wood in waste wood disposal sites and building demolition materials. It cannot be a practical discriminating means because it cannot cope with the above.

    The present invention has been made in view of the above-mentioned problems of the prior art, and is a wood in which a toxic metal compound is impregnated and applied from a large amount of waste wood by using an optical detection technique, particularly CCA. CCA-treated wood impregnated and coated with wood preservatives can be quickly and non-destructively identified, separated and sorted, and the automation of the sorting work and cost reduction will be realized.

  In other words, waste wood from the dismantling of houses is converted into chips as recycled resources, and recycled wood boards (wood boards produced using crushed construction wood), recycled wood mulching materials (weed prevention materials and plant growth) Recycled waste wood as a material that protects and promotes waste), compost, etc. and carbonized to be used effectively as raw materials for wood fuel, activated carbon, environmental cleaners, soil conditioners, etc. is there.

  CCA preservatives are compounds of chromium, copper, and arsenic, and there are No. 1, No. 2, and No. 3 depending on their mixed distribution. In this case, the effective component is a chromium compound (as CrO3), a copper compound (as CuO), an arsenic compound (as As2O5), No. 1 is a compound containing 20% or more of a chromium compound and a small amount of arsenic. There are a salt type produced using a copper salt and an oxide type produced using an oxide.

This CCA preservative has been used in Japan since about 1968, and has been used about 100,000 tons annually since around 1960. The safety aspect has been pointed out at the peak of 1992 and has recently been decreasing. However, unlike creosote oil that has been used for utility poles and sleepers, CCA-treated wood is water-soluble and colorless and odorless, so it is mainly used for residential foundations and architectural applications at about 300,000 m ³ / year. . Particularly recently, CCA-treated timber processed from the United States and Canada has come to be imported, and the amount of CCA-treated timber used for housing, gardening materials, park materials, etc. tends to increase.

  The wood impregnated and coated with the toxic metal compound mentioned here, particularly the wood impregnated and coated with the CCA wood preservative, etc. is mainly used in the following applications. Wooden building foundations, joists, floorboards, pillars, braces, balcony materials, terrace materials, wet edges, wooden fences, wooden utility poles, sleepers, street tree pillars, garden tree pillars, container panels for luggage transportation, foundation piles for civil engineering, Wooden bridges, wooden logs, park snails, benches, gardening materials, etc.

The CCA preservative injected into the CCA-treated wood generates a compound that is hardly soluble in water in the wood after being injected into the wood, and is fixed to the wood as an organometallic compound. The reaction formula of CCA-1 is as follows.
2CuSO4 + 4K2Cr2O7 + 5AS2O5 · 2H2O → 8CrAsO4 + 4CuHAsO4 + 2K2SO4 + 4KOH + 7H2O + 12O ↑
However, this chemical reaction has a fixing time of 3 weeks due to the relationship between the temperature after injection, tree species, the speed of drying and the amount of absorption, but its behavior is not clear because it changes depending on the factory and time management.

  According to the experiment on chemical substances from waste wood conducted by the Waste Research Foundation, the heavy metal content of CCA-treated wood was measured (Table 1). The average heavy metal content was 1053 mg / kg chromium and 425 mg / kg copper. Arsenic is reported to be 460 mg / kg.

That is, the CCA wood preservative is a chemical structure in which a component of wood (cellulose, hemicellulose, lignin, etc.) and a metal salt are included, and an organic compound contains a metal. These liquid organometallic compounds generally become more stable as they contain a large amount of heavy metals, and organometallic compounds are extremely toxic and feature methylmercury, organotin compounds, CCA wood preservatives. Represented by agents such as diethyl zinc.
The chemical structure forms are classified into the following three types.
(1) Ion-binding compound: Metal salt of acid or alcohol (2) Covalent compound: A compound in which a carbon atom and a metal are bonded to each other with an organic metal compound.
(3) Coordinative binding compound: A complex metal in which molecules or anions are coordinated to a metal.
Chromium / copper / arsenic compounds (CCA), phenols / inorganic fluoride compounds (FCAP), alkylammonium compounds (AAC), chromium / copper / zinc compounds (CFKZ) used as wood preservatives, Copper / alkylammonium compounds (ACQ), copper / boron / azole compounds (CUAZ), boron / alkylammonium compounds (BAAC), fatty acid metal salt compounds (NCU {copper naphthenates} / NZN {naphthenes) Water-soluble preservatives such as zinc oxide compounds} / VZN {zinc versatic acid compounds}) and azole compounds (AZP) are complex combinations of the ionic bonds, covalent bonds, and coordinate bonds described above. Is easily soluble in water and highly reactive, and covalent bonds and complex metals are stable with low reaction. The organometallic compound is represented by an alkyl group with a covalent bond, and the complex metal is often a double or triple bond. Organometallic compounds and complex metals are often difficult to distinguish.

  In general, an infrared absorption spectrum (abbreviated as IR) is a curve drawn by irradiating a sample with infrared light emitted from a light source, and the infrared light absorbed by the sample by wavelength and absorbance. Represents. These infrared absorption spectra are unique in that they show the characteristics of the chemical structure of the molecule of an organic compound. Since various information on the molecular structure, electronic state, functional group, etc. can be obtained, confirmation of the structure, qualitative, quantitative, etc. Used for

  However, in the fingerprint region (mid-infrared) of the infrared absorption spectrum, the influence of thermal radiation from the sample, the influence of air and moisture is large, and it is not possible to measure non-destructively the test wood with various surface states. It is extremely difficult.

On the other hand, near-infrared light and visible light are light having a shorter wavelength than that of mid-infrared light (wavelength: 380 nm to 2500 nm) and are less affected by heat, air, and moisture, and are suitable for nondestructive measurement outdoors. However, absorption peaks attributed to electron excitation, functional group double vibration, etc. have a wide absorption line width and have the disadvantage that the spectrum changes due to various factors. This is an unused light region.

However, for visible light and near-infrared light, it is possible to easily construct an optical system using existing optical components such as optical fibers and glass lenses that are available at low cost. It is considered important in measurement.

  For non-destructive non-contact measurement, a spectroscopic analysis method using reflected light is a promising means, but the reflected light largely depends on the surface condition of the sample (surface roughness, reflection angle, dirt, moisture, etc.). It is necessary to develop methods that are not affected by these effects.

  In the present invention, as a result of intensive research as a technical subject, a method for determining the presence or absence of harmful wood preservatives contained in the above-mentioned preservative treated wood, particularly CCA treated wood, wood impregnated and coated with CCA wood preservatives. However, the present invention relates to an optical CCA-treated wood detection method using the characteristics, which is found to have a difference in reflection characteristics in specific bands of visible light and near-infrared light with ordinary wood.

  In the experiment, the present inventors irradiated a sample with visible light or near-infrared light having a plurality of wavelengths onto a CCA-treated wood, and analyzed the reflection spectrum. As a result, the CCA compound was observed in the near-infrared light wavelength band of 600 to 1050 nm. It was found that the decrease in the absorption characteristics was remarkable, and that the difference in absorption due to the presence or absence of the CCA compound was small (graph 1) at 1200 to 1600 nm. It was also confirmed that near-infrared light has a longer wavelength than visible light and thus has high transmission characteristics and is resistant to dirt on the surface of the wood to be inspected. When the wood to be inspected is wet, there is a concern that the absorption near 1450 nm, which has a moisture absorption peak, increases and is affected, but it was also confirmed that the influence of moisture can be reduced by avoiding this band. .

Graph 1

  These characteristics are almost independent of the species of wood used as the raw material of the timber to be examined, and it has become clear from measurements in coniferous and broad-leaved rice pine, red pine, cedar, spruce, tsuga, zelkova, walnut and oak. It has also been confirmed that although there is a difference between the core material and the sap material in the short wavelength range (blue, green) of visible light, there is almost no difference in the near infrared region and no disturbance factor.

  As an example, the second derivative of the reflection spectrum shown in graph 2 shows that the peak at a specific wavelength changes depending on the content of CCA. However, the present invention is not limited to this example.

Graph 2

  In order to support the reliability of these optical detection experiment results, the present inventors determined the CCA wood preservative based on the determination of the infrared absorption spectrum and fluorescence intensity ratio, color reaction, nuclear magnetic resonance, elemental analysis, etc. Judgment was made using a chemical method. From these experiments, the present inventors have clarified that the presence or absence of CCA wood preservative can be significantly determined by an optical method.

  In this way, the present inventors have found that the peaks and inflection points peculiar to wood in the reflection spectrum have changed due to the binding of CCA, and that CCA itself has a specific spectrum, and its characteristics even after coating and impregnation on wood. We have succeeded in demonstrating the research to detect the presence and concentration of CCA from the analysis of the high-order differential waveform of the spectrum.

  Also, if the wood preservative penetrates only inside the wood, there is a concern that it will be impossible to discriminate from the surface with light, but wood is used for preservative treated wood including CCA treated wood. Since it is processed by pressure injection or application from the wood surface after processing into a state, the injected wood preservative generates and settles a compound along the grain centering on the wood surface, and only the surface is preserved No sample lacking agent was found.

  The present invention makes use of the properties of near-infrared light to instantly and non-destructively determine the presence and concentration of CCA wood preservatives impregnated and applied to wood. The present invention relates to a CCA-treated wood discriminating apparatus using an optical CCA-treated wood detection technique to be measured.

The inventors have a wavelength of 964 nm ± 20 nm attributed to the CCA wood preservative contained in the wood, a wavelength of 815 nm of the CCA preservative alone and a wavelength of 922 nm ± 20 nm not attributed to the CCA wood preservative contained in the wood. Identify and calculate the intensity of the reflected light as well as the second derivative, and based on the calculation result, determine whether or not the poisonous CCA wood preservative containing copper, chromium and arsenic contained in the wood is impregnated or applied. I found out to judge.
The apparatus includes a light source unit that irradiates near-infrared light of 2500 nm or less on the wood to be inspected, a light-receiving unit that receives reflected light from the wood, and a wavelength of 964 nm that is attributed to either CIR or irradiated light. A spectroscope that divides light into a wavelength of 922 nm that does not belong to the light CCA, and an absorbance digital that calculates the absorbance at a wavelength of 964 nm that belongs to the CCA and the absorbance at 922 nm that does not belong to the CCA from the reflected light received by the light receiving unit A signal processing device and a central processing unit (CPU) for calculating the second derivative of the absorbance are used to correct the presence / absence and concentration value due to the absorbance of the CCA, and the following equation 1 Non-destructive and non-contact judgment of the presence or absence of impregnation or application of toxic CCA wood preservatives containing copper, chromium and arsenic to the wood, and display or warning of the judgment result Or is an optical discrimination system CCA treated wood to be able to relay contact output.
In Equation 1, λ is the wavelength, Α ₁ (λ ₁ ) is the absorbance at wavelength λ ₁ (964 nm) attributed to CCA, and Α ₂ (λ ₂ ) is the wavelength λ ₂ (922 nm) not attributed to CCA. , K0, K1, and K3 are coefficients determined by the least square method using the absorbance measured from the wood impregnated with the CCA concentration 2% adjustment liquid.

Formula 1

Ｃ：ＣＣＡ有無
λ: 波長
Α_１(λ_１): 波長λ₁における吸光度
Α_２(λ_２): 波長λ₂における吸光度
K０、K１、K３: 係数

C: CCA presence / absence λ: wavelength Α ₁ (λ ₁ ): absorbance at wavelength λ ₁ Α ₂ (λ ₂ ): absorbance at wavelength λ ₂
K0, K1, K3: coefficients

The method of determining the presence or absence of impregnation or application of the CCA wood preservative having the above structure and the optical wood preservative detection device, the CCA wood preservative impregnation or application of the wood to be inspected generated from the building demolition site, etc. If it is applied for discrimination at the time of separation / sorting and receives reflected light from the wood to be inspected, it becomes possible to discriminate CCA wood preservative impregnation or coated wood and CCA concentration.
The present inventors made a CCA-treated wood sample in which the content of the CCA wood preservative was changed in order to confirm the above-mentioned action, and as a result of performing absorbance measurement and second-order differential treatment by the CPU in the range of 800 nm to 1000 nm, It was found that there is a beak on the arrow shown in graph 3 depending on the content of the CCA wood preservative.

Graph 3

  From the calculation results of graph 2, a peak is observed in the absorption spectrum depending on the content of the CCA wood preservative, and the absorbance at a wavelength of 964 nm ± 20 nm attributed to the CCA wood preservative and the absorbance at a wavelength of 922 nm ± 20 nm not attributed to the CCA wood preservative. In addition, in order to confirm whether the peak of the absorption spectrum is attributed to the CCA wood preservative, the wood to be inspected is applied with hibermata, hiba noguchi, Sawara CCA application (none), Sawara CCA application (present ), Soot CCA impregnation (many) and soot CCA impregnation (small). As a result, when the absorption spectra were compared between various woods not containing the CCA wood preservative and the CCA-treated woods, a peak of absorbance appeared remarkably in the vicinity of a wavelength of 964 nm ± 20 nm. (Graph 4)

Graph 4

Since this central processing unit (CPU) is used to correct the calculation using the second derivative value, it is possible to process the data to remove the disturbance factors attached to the wood type and the surface as much as possible. When determining whether or not a preservative is impregnated or applied, it is possible to perform highly discriminative measurement. Therefore, an absorbance digital signal processing device for calculating the impregnation value and absorbance of CCA-treated wood impregnated with 2% diluted CCA wood preservative in a cocoon, and a central processing unit (CPU) for calculating the second derivative of these absorbances. Table 3 and graph 5 compare the measured values measured using the CCA discriminating / measuring instrument according to the present invention. Obviously, the CCA wood preservative 2% impregnated wood is different from other wood, and the error in the measured numerical value of the CCA discrimination measuring instrument is very small. Therefore, the CCA-treated wood can be discriminated reliably.

Graph 5

  The present invention irradiates light to be inspected wood with light including a specific wavelength band using a lighting device, and splits the reflected light into a specific wavelength band for the purpose of determining the presence or absence of the CCA wood preservative from the inspected wood. Captured by a spectroscope, the reflected light intensity is calculated by a signal processing device, further calculated by a central processing unit (CPU) that calculates the second derivative of the absorbance, and the presence and concentration due to the absorbance of the CCA preservative This is an optical CCA-processed wood discriminating apparatus that corrects numerical values, and further allows determination results to be output to an output device.

In the following, the system configuration of the CCA-treated wood discriminating apparatus using the optical wood preservative detection method provided in the present invention will be described with reference to FIG. However, the scope of the present invention is not limited to the examples described below.
Any light source may be used as long as the light source used in this apparatus can generate continuous spectrum light with all or part of visible light and near infrared light. A low-priced and relatively long-life halogen lamp is suitable for this apparatus, but other light sources such as metal halide lamps, xenon lamps, and light-emitting diodes can also be used as appropriate. The structure of the light emitting unit needs to be miniaturized for portable use, and needs to be a sensor to which one end of a light emitting lamp and a light receiving optical fiber is attached, such as the optical sensor device of Patent Nos. 3056458 and 3056459, etc. Is suitable.

Any spectroscope may be used as long as it can separate (spectroscope) visible light or near-infrared light according to wavelength. A combination of a diffraction grating and a light receiving element array, or a combination of a mechanically driven diffraction grating and a light receiving element is a common configuration, but an AOTF, a photonic crystal, or the like can also be used. It is also possible to perform spectroscopy by combining a plurality of filters.

The light intensity detector is generally a photodiode, but any element may be used as long as it can finally convert the light intensity into an electric signal, such as a pyroelectric sensor or CdS.

Spectral data calculators are generally configured to operate with a microprocessor after being converted to digital data by an analog-to-digital converter. However, they are operated with a DSP (digital signal processor) or a digital calculator using logic elements. May be. It is also possible to directly calculate an electrical signal with an analog calculator. These are all known to those skilled in the art and can be appropriately selected.

Reporting / displaying of the presence / absence of preservatives and the concentration / indicator can be used as appropriate, such as LED (light-emitting diode), liquid crystal, EL (electroluminescence) display, relay contact, sound source using buzzer or speaker. It is.

As the optical fiber for making the detection head small and flexible, a single line or a collective line of a multimode fiber is preferable from the viewpoint of cost and optical coupling, but a single mode fiber can also be used. Glass fiber is suitable because it has low loss and no specific absorption in a wide range from visible to near infrared, but plastic fiber is low in price and strong in bending and can be selected based on the design policy.

In addition to primary batteries such as manganese batteries, alkaline batteries, and lithium batteries, secondary batteries such as nickel cadmium batteries, nickel metal hydride batteries, lithium ion batteries, and lead batteries, and fuel cells can be used to make the device portable. It can be selected as appropriate. Also, a large capacity capacitor such as an electric double layer capacitor can be used.

  With the configuration as described above, it is possible to specify the presence or absence of CCA wood preservatives by using the present invention, and it is easy to reduce the size of photosensors and photosensors at construction sites, wood factories, waste wood processing factories, etc. It is clear that CCA-treated timber can be discriminated, and it is clear that there will be a way to separate and separate CCA-treated timber from waste timber, which was impossible before.

The wood preservative detection method provided in the present invention is achieved by the process shown in the flowchart of FIG.

Explanatory drawing by the flowchart which concerns on this invention

Claims (6)

  Wavelength characteristics (reflection spectrum) of the reflectance of light by irradiating visible light (380 nm to 780 nm) or near-infrared light (780 nm to 2500 nm) to the inspected wood impregnated or coated with wood preservatives An optical detection method for wood preservatives in wood that reads the phenomenon of change in the wood, determines the presence or absence of wood preservatives on the inspected wood, and derives and reports the concentration. The wood to be inspected is irradiated with light having a spectrum continuous to all or part of visible light or near infrared light (visible light to near infrared light having a wavelength of 380 nm or more and 2500 nm or less) of claim 1, and reflected light thereof. To measure the reflection spectrum, calculate the reflection spectrum data, determine the presence or concentration of wood preservatives impregnated or applied to wood, and report and display the results. Method for optical detection of wood preservatives in wood. An illumination device capable of irradiating the inspected wood with light having a continuous spectrum of part or all of the visible light or near-infrared light of claim 1, a spectroscope capable of spectroscopically reflecting the reflected light from the inspected wood, A detector that converts the light intensity dispersed by the spectroscope into an electrical signal, an arithmetic unit that can perform operations on the obtained spectral data (reflection spectrum), and the presence or absence of wood preservatives based on the calculation results An optical detector for wood preservatives in wood, which consists of a display that displays and reports the concentration. 4. An optical detection device for wood preservatives in wood according to claim 3, wherein a battery is mounted and power can be supplied from the battery to the light source, the spectroscopic device, the light intensity detection unit, the calculation unit, and the notification / display unit. The light obtained from the visible light or near-infrared light source of claim 1 is applied to the wood to be inspected through the optical fiber or directly from the light source, and the reflected light is applied to the spectroscope through another optical fiber that is the same or in parallel. 4. An optical detection device for wood preservatives in wood according to claim 3, which is introduced into the wood. From the reflection spectrum intensity obtained by irradiating the inspected wood with near-infrared light, light having a wavelength of 964 nm ± 20 nm and a wavelength of 815 nm ± 20 nm belonging to a wood preservative (CCA) containing copper, chromium and arsenic, Non-destructive and non-contact determination of the presence or absence of wood preservative (CCA) impregnation or application to the wood to be inspected using the following formula 1 for the second derivative of the absorbance of light with a wavelength of 922 nm ± 20 nm not belonging to CCA And a method for optically detecting wood preservative (CCA) in wood so that the judgment result can be displayed on the screen or output a warning sound or relay contact.
Formula 1

In Equation 1, λ is the wavelength, Α ₁ (λ ₁ ) is the absorbance at wavelength λ ₁ (964 nm) attributed to CCA, and Α ₂ (λ ₂ ) is the wavelength λ ₂ (922 nm) not attributed to CCA. , K0, K1, and K3 are coefficients determined by the least square method using the absorbance measured from the wood impregnated with the CCA concentration 2% adjustment liquid.

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