JP2003302333A - Diagnostic method for in-duct contamination and simple evaluation method for duct cleaning effect - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To evaluate a dust cleaning effect simply, instantly, quantitatively and precisely when an in-duct contamination is diagnosed. <P>SOLUTION: An adhesive tape 2 is pasted on a prescribed position at the inside of a duct 1, stuck particles 3, 3, etc., and so on deposited at the inside of the duct are transferred to the adhesive tape 2, the adhesive tape 2 is photographed by a microscope, a photographed image is fetched by a computer 8, the photographed image is binarization-processed by the computer 8, a projection area of the stuck particles is divided by an area of the whole photographed image so as to find an area rate of the stuck particles, and a contamination degree inside the duct is decided on the basis of the area rate of the stuck particles. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the degree of contamination in an air conditioning duct and simply evaluating the duct cleaning effect.

[0002]

2. Description of the Related Art For large buildings such as buildings, factories and hospitals, it is necessary to keep the conditions such as temperature and humidity, air flow, dust, number of microorganisms, odor, etc., to optimum conditions for humans and articles in the building. Air conditioning is installed for the purpose. In the air conditioning, the duct serves as an air carrying path.

Particles adhere to and accumulate on the inner surface of the duct over time, and since it is a favorable environment for microorganisms to inhabit, the degree of contamination increases as the amount of dust and microorganisms gradually increases. Therefore, it is important to accurately grasp the degree of pollution of the duct, and it is necessary to quantitatively evaluate the effect when the duct is cleaned.

[0004] Conventionally, the diagnosis of contamination in the duct is generally performed by visual inspection, and the effect of removing adhered particles by cleaning the duct is to remove the adhered particles on the inner surface of the duct with a chemical rag such as a wiper for clean room before and after cleaning the duct. Wiping, a wiping method for measuring the weight of the chemical wipe, or sticking an adhesive tape on the inner surface of the duct, transferring the adhered particles on the inner surface of the duct to the adhesive tape before and after cleaning, transmitting light to this adhesive tape, Light transmission method to measure the light transmittance, further after applying the test solution from the chemical wipe to the medium, cultured for a certain period, by counting the number of colonies that have grown, adhered microorganisms on the inner surface of the duct before and after cleaning the duct A method for counting the number of microorganisms for measuring the number is known.

[0005]

However, in the case of the visual diagnosis method, it is not possible to quantify the concrete degree of contamination, and therefore individual differences among diagnosticians are likely to be evaluated. There was a problem.

On the other hand, in the wiping method, although quantification is possible to some extent, the weight of the chemical wipe is influenced by the humidity of the measuring environment. In order to suppress this effect, it is necessary to leave the chemical rag for at least one day in a desiccator whose humidity has been adjusted, so that quick evaluation cannot be performed and it is not immediate. Furthermore, when the degree of contamination in the duct becomes extremely low after cleaning, the amount of particles wiped off may not be measured by the existing balance, and there is a problem such as lack of accuracy.

In the case of the light transmission method, although it has immediacy, it is not possible to accurately measure the amount of particles because it is affected by the color of the particles, and the adhesive tape for measurement has a variation in the light transmittance, which causes correction. There was a problem such as being necessary. Although the method of counting the number of microorganisms is highly accurate, it has a problem that it requires culturing and it is not possible to quickly obtain an evaluation immediately after cleaning. Specifically, microorganisms include bacteria consisting of prokaryotic cells and fungi such as mold and yeast consisting of eukaryotic cells, but it is fungi that easily grow in the duct, and it is necessary to culture 5 to 5 such fungi. It takes about 7 days.

[0008] Therefore, the main object of the present invention is to make it possible to easily and immediately evaluate quantitatively and accurately the diagnosis of duct contamination and the evaluation of duct cleaning effect.

[0009]

As a result of various studies to solve the above problems, the present inventors have found that the ratio of the projected area of adhered particles to the visual field area and the amount of accumulated particles in the duct are In addition to being proportional, it was found that the amount of accumulated particles is proportional to the number of microorganisms in the duct.

That is, according to the present invention, if the area ratio is large, it can be evaluated that the pollution degree is high because the number of accumulated particles is large and the number of living microorganisms is large, and conversely, if the area ratio is small, the number of accumulated particles is large. The present invention according to claim 1 for solving the above-mentioned problems is based on the finding that the degree of pollution can be evaluated to be low because the number of living organisms is small and the number of living microorganisms is small. An adhesive tape is attached to a predetermined position on the inner surface of the duct, and after the adhered particles accumulated on the inner surface of the duct are transferred to the adhesive tape, the adhesive tape is photographed by a microscope and the photographed image is taken into a computer, and the computer The binarization processing of the photographed image is performed to obtain the ratio of the projected area of the adhered particles to the area of the entire photographed image, and the duct is based on the projected area ratio of the adhered particles. Diagnostic methods in the duct contamination, characterized in that to determine the degree of contamination is provided.

In the invention according to claim 1, the degree of contamination in the duct is determined by the projected area ratio (hereinafter, also referred to as area ratio) of the adhered particles. The determination may be performed, for example, by ranking according to the area ratio and quantitative evaluation may be performed, or may be determined from a correlation diagram between the area ratio and the amount of adhered particles, a correlation diagram between the amount of adhered particles and the number of microorganisms, and the like. You may do it.

[0012] With such a method, a series of work can be completed in a few minutes to several tens of minutes, and it is possible to make a simple and immediate evaluation, and to make a quantitative and accurate judgment regardless of individual differences. Become.

According to the second aspect of the present invention, an adhesive tape is attached to a predetermined position on the inner surface of the duct before and after cleaning the duct, and after the adhered particles deposited on the inner surface of the duct are transferred to the adhesive tape, The adhesive tape is photographed by a microscope, the photographed image is taken into a computer, the photographed image is binarized by the computer, and the ratio of the projected area of the adhered particles to the entire area of the photographed image is obtained. There is provided a simple method for evaluating a duct cleaning effect, characterized by evaluating the duct cleaning effect by comparing the projected area ratio of the adhered particles before the duct cleaning and the projected area ratio of the adhered particles after the duct cleaning.

According to the second aspect of the invention, the duct cleaning effect is evaluated by comparing the area ratio of the adhered particles before the duct cleaning and the area ratio of the adhered particles after the duct cleaning.

According to a third aspect of the present invention, the adhesive tape is a colored tape, and by irradiating light from an obliquely upper 360 ° direction during photographing with a microscope, image preprocessing is performed during binarization processing in the computer. A method for diagnosing contamination in a duct or a simple method for evaluating a duct cleaning effect according to any one of claims 1 and 2 in which the above is substantially unnecessary.

In the invention described in claim 3, a colored tape, preferably a black tape is used as the adhesive tape in order to eliminate the influence of the reflected light and effectively capture only the scattered light of the adhered particles at the time of photographing with a microscope. At the same time, the light was radiated from the obliquely upper 360 ° direction at the time of microscopic photography. As a result, the binarization can be easily performed without performing image preprocessing such as edge enhancement and hole filling during the binarization processing in the computer. When a colored tape is used, the light source color is made complementary to the background color (tape background color), and the background of the captured image is made black to make only the particle image stand out by performing image signal processing. It becomes possible.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Diagnosis Method for Duct Contamination] As shown in FIG. 1, a black adhesive tape 2 is attached to a predetermined place in the duct 1, and a constant pressure is applied by a pressure roller (not shown). By peeling off the adhesive tape 2 from the duct 1, the adhered particles 3 on the inner surface of the duct 1 are transferred to the adhesive tape 2, and the adhesive tape 2 is wound on the surface of the slide glass 4 as shown in FIG. Turn on
A measurement sample 5 is created.

When transferring the adhered particles 3 on the inner surface of the duct 1 to the adhesive tape 2, an adhesive sheet test method (JIS Z 0237)
It is desirable to carry out according to. The test method is about 15 cm
After sticking the adhesive tape 2 on the inner surface of the duct 1, a 2 kg pressure roller is reciprocated 5 times on the upper surface of the adhesive tape 2 to transfer the adhered particles 3 on the inner surface of the duct 1 to the adhesive tape 2. , 180 ° peeling method is defined as peeling from the inner surface of the duct 1.

The material of the adhesive tape 2 is as follows.
Any material such as rubber-based, acrylic-based, vinyl ether-based, and urethane-based materials that can be usually used as the material of the adhesive tape may be used. When blackening,
Either a method of applying a paint containing a black pigment on the surface or adding it to the resin itself at the stage of manufacturing the tape substrate can be adopted.

Next, as shown in FIG. 2, the measurement sample 5 is photographed by a digital microscope 6 having a resolving power of preferably 1 μm or more in order to accurately display adhered particles described later, and the image is stored in a memory. The image recorded on the card 7 is read into the computer 8, the image recorded on the memory card 7 is loaded into the computer 8, and the computer 8 binarizes the photographed image. Try to find the "area ratio" of the adhered particles. It should be noted that the computer 8 may be directly loaded by a cable connection or the like without using the memory card 7.

When the image is taken by the digital microscope 6, as shown in Example 2 which will be described later, the obliquely upper portion 36
Light is emitted from the 0 ° direction. By using a black tape as the adhesive tape 2 and irradiating light obliquely from the upper 360 ° direction for photographing, as shown in FIG. 3, the reflected light from the tape incident on the microscope lens is suppressed as much as possible. Therefore, only the scattered light of the adhered particles can be effectively captured. As a result, it is possible to substantially eliminate the need for image preprocessing during the binarization processing by the computer 8. Conventionally, in this type of computer binarization processing, it is necessary to perform image preprocessing such as edge enhancement and hole filling so that the background and the particle image can be clearly distinguished. It was done based on the subjective judgment of the person. The former edge enhancement processing is to detect a large amount of change in the image data by differentiating the RGB values and the brightness of the image data when the outline of the object is blurred and not clear. , The process of clarifying the edge of the object.The latter hole filling process is a process of binarization when there is a shadow due to the adjustment of light at the shooting stage or a dropout occurs in the image. Before performing, it refers to a process of filling the missing part with the same color as the object in order to recognize it as the object.

By the way, the background color of the adhesive tape 2 may be a color other than the black color. In this case, by performing the image signal processing, it is possible to make the background of the captured image black and raise only the particle image. For example, set the background color to magenta (RGB value:
& hff00ff), the light source color is white (RGB value: & hffffff), and the background of the captured image is black (& hff00ff- &
hff00ff = & h000000), and the particle image is a scattered light color (& hffff
Color close to ff)-& hff00ff, which means that you will be shooting in green (& h00ff00).

Further, by using a light source color which has a complementary color relationship with the color of the adhesive tape, it is possible to raise only the particle image with the background of the photographed image as a monotone. For example, set the background to magenta (RG
By setting the B value: & hff00ff) and the light color to green (RGB value: & h00ff00), the background of the captured image will be black and the particle image will be captured in green, as in the case of the image signal processing. become.

In order to diagnose the duct contamination degree based on the area ratio of the adhered particles, it is known that the area ratio is proportional to the amount of adhered particles and the amount of adhered particles is proportional to the amount of microorganisms. For example, ranking may be performed according to the area ratio and quantitative evaluation may be performed, or determination may be made from the correlation diagram between the area ratio and the amount of adhered particles, the correlation diagram between the amount of adhered particles and the number of microorganisms, and the like. Good.

Further, since it is possible to predict the amount of adhered particles over time, it becomes possible to determine how many years later the duct should be cleaned, and the number of adhered microorganisms in the duct can be obtained from the area ratio. .

[Simplified Evaluation Method of Duct Cleaning Effect] Next,
A simple evaluation method of the cleaning effect based on the method for diagnosing contamination in the duct will be described. Since the method for diagnosing contamination in the duct can diagnose the degree of contamination regardless of the amount of particles adhering to the duct, before and after cleaning the duct. After that, the measurement sample 5 is collected according to the same procedure, and the digital microscope 6 is used.
, And record the image on the memory card 7,
The image recorded in the memory card 7 is loaded into the computer 8, and the computer 8 binarizes the photographed image. The ratio of the projected area of the adhered particles to the entire area of the photographed image, that is, the “area ratio of the adhered particles” To be asked.

Then, the duct cleaning effect is evaluated by comparing the area ratio of the adhered particles before the duct cleaning with the area ratio of the adhered particles after the duct cleaning. This measurement is
Since it takes only several minutes to several tens of minutes, it is possible to know the duct cleaning effect immediately after cleaning.

[0029]

Example 1 In Example 1, the knowledge obtained by the present inventors through experiments, that is, the ratio of the projected area of adhered particles to the visual field area (area ratio) is proportional to the amount of accumulated particles in the duct. An experimental example relating to the finding that the amount of accumulated particles is proportional to the number of microorganisms in the duct will be described in detail.

(1) Prediction Formula for Deposited Particles in Duct First, prior to the experiment, the present inventors assumed a predictive formula for the relationship between the area ratio and the elapsed time from the adhesion state of the deposited particles in the duct.

It is assumed that the area of the adhered particles 3 deposited on the duct 1 per unit time is constant. The overlapping area between the adhering particles is proportional to the area of the adhering particles 3. If the above assumption holds, the increase in the area of the adhering particles 3 due to the deposition is the total area of the adhering particles 3 minus the overlapping area. This relationship can be expressed by the following equation (1). Then, when t = 0, the following equation (2) can be derived by integrating and rearranging both sides of the following equation (1) under the condition of C = 0. On the other hand, when t = ∞ and C = 1,
Co = A is obtained from the following equation (2), and by substituting this relationship into the following equation (2), the following equation (3) can be derived.

[0032]

[Equation 1]

(2) Relationship between area ratio and adhered particles As shown in FIG. 4, a plurality of glass slides 4 coated with Vaseline mucosa were placed in the air supply duct 1 and left for 90 days, 21 days.
The slide glass 4 that has been exposed for 0 days and 1200 days and collected adhered particles is used as an image processing / analyzing device SPICA (Speedy P
The number of particles, the area, etc. were analyzed by article Image & Color Analysis, manufactured by Japan Avionics Co., Ltd.).

The results of the above test are shown in FIG. FIG. 5 is plotted on a graph in which the vertical axis is the area ratio and the horizontal axis is the elapsed time, and a prediction line for the elapsed time and the area ratio is drawn according to the above mathematical expression 1. From FIG. 5, it was confirmed that the area ratio increased with the passage of time, and that the above-mentioned predicted line and the actually measured value substantially matched.

The particle weight after 1200 days was measured by the wiping method and plotted on a graph in which the vertical axis represents the particle weight and the horizontal axis represents the area ratio shown in FIG. The actual values when measuring the duct of the building were plotted. Since the area ratio of the actual measurement value after 19 years is unknown, the value of the above-mentioned prediction formula was adopted. It was confirmed from FIG. 6 that the particle weight is in a proportional relationship with the area ratio. In addition, based on these relationships, FIG. 7 shows the results of predicting the change over time in the weight of the deposited particles in the duct.

(3) Relationship between the amount of adhered particles and the number of adhered fungi The amount of adhered particles is measured by the wiping method at three locations in the duct where the deposition conditions are different, and the particle size is measured by a chemical wipe. Solution and test solution were diluted 10 times, and 0.5 ml of each solution was applied to two kinds of PDA medium, and then cultured at 25 ° C for 5 days, and the number of developed colonies (the number of colonies) was defined as the number of adherent fungi. .

The results are shown in FIG. From the figure, it was confirmed that the amount of adhered particles and the number of adhered fungi have a clear proportional relationship. Further, from the regression line, it is predicted that 1 g of deposited particles contains about 40,000 fungi.

[0038]

[Embodiment 2] In particular, in the present invention, a black tape is used as an adhesive tape so that pre-processing is not required during binarization processing in a computer, and light is obliquely irradiated from an upward 360 ° direction during microscopic photography. I am trying. In the second embodiment, various examination experiments conducted up to this method will be described.

FIG. 9 shows an image photographed by using a black tape as an adhesive tape according to the method of the present invention and irradiating light from an obliquely upper 360 ° direction when photographing with a microscope, and a binarized image thereof. At the shooting stage, the background and the particle image were already clearly distinguished, and it was confirmed that binarization is possible without pretreatment.

On the other hand, in the example shown in FIG. 10, a transparent tape is used as an adhesive tape, and a photographed image in the case of the conventional method photographed by irradiating light from directly above and its binarization It is an image. It can be seen that the background is reflected in the binarized image, omission occurs in the particle image, and the shadow of the particle is further reflected. In the case of simple binarization, the particle image cannot be captured accurately and preprocessing is required.

The example shown in FIG. 11 is a photographed image in the case of the conventional method in which a black tape is used as the adhesive tape and light is irradiated from directly above, and a binarized image thereof.
Although the black tape is used, since the light is emitted from directly above, the background is projected, and in the case of simple binarization, not only the particle image but also the image on the tape surface is picked up. Therefore, it is necessary to remove the image on the tape surface by pretreatment.

Further, the example shown in FIG. 12 is a photographed image photographed by irradiating light from four directions using a black tape as the adhesive tape. Also in this case, a shadow was generated in the particle image, and the particle image could not be clearly captured.

[0043]

As described above in detail, according to the present invention, in diagnosing the contamination in the duct and evaluating the duct cleaning effect,
It becomes possible to evaluate these easily and immediately, quantitatively and accurately.

[Brief description of drawings]

FIG. 1 is a diagram of transferring adhered particles 3 on the inner surface of a duct 1 to an adhesive tape 2, where (A) is the inner surface of the duct 1 and (B) is a measurement sample 5.
FIG.

FIG. 2 is an area ratio measurement procedure diagram of a measurement sample 5.

FIG. 3 is a diagram showing a shooting procedure by the digital microscope 6.

FIG. 4 is a measurement procedure diagram in the first embodiment.

FIG. 5 is a correlation diagram between an area ratio and elapsed time.

FIG. 6 is a correlation diagram between the area ratio and the amount of adhered particles.

FIG. 7 is a correlation diagram between the amount of adhered particles and the number of years elapsed.

FIG. 8 is a correlation diagram between the number of adhered microorganisms and the amount of adhered particles.

FIG. 9 is an image taken according to the method of the present invention and a binarized image thereof.

FIG. 10 is a photographed image and a binarized image thereof by the comparison method (No. 1).

FIG. 11 is a photographed image and a binarized image thereof according to the comparison method (Part 2).

FIG. 12 is a photographed image when light is irradiated from four directions.

[Explanation of symbols]

1 ... Duct, 2 ... Adhesive tape, 3 ... Adhesive particles, 4 ... Slide glass, 5 ... Measurement sample, 6 ... Digital microscope, 7
... memory card, 8 ... computer, 9 ... captured image,
10 ... Binary image

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2G052 AA04 AA40 AC23 AD12 AD52                       FD03 GA32 JA16                 2G059 AA05 CC19 DD12 DD13 EE02                       EE13 FF01 FF03 GG10 HH02                       KK04 MM01 MM09 MM10 PP04                 3L080 AD01 AE04

Claims (3)

[Claims] 1. An adhesive tape is attached at a predetermined position on the inner surface of a duct, and after the adhered particles deposited on the inner surface of the duct are transferred to the adhesive tape, the adhesive tape is photographed by a microscope and a photographed image is displayed on a computer. The captured image is binarized by the computer to obtain the ratio of the projected area of the adhered particles to the entire area of the captured image, and the contamination degree in the duct is calculated based on the projected area ratio of the adhered particles. A method for diagnosing contamination in a duct characterized by making a judgment. 2. An adhesive tape is adhered to a predetermined position on the inner surface of the duct before and after cleaning the duct, the adhered particles accumulated on the inner surface of the duct are transferred to the adhesive tape, and then the adhesive tape is photographed by a microscope. Then, the captured image is loaded into a computer, the binarization processing of the captured image is performed by the computer, and the ratio of the projected area of the adhered particles to the area of the entire captured image is obtained. A simple method for evaluating a duct cleaning effect, which comprises evaluating a duct cleaning effect by comparing a projected area ratio with a projected area ratio of adhered particles after duct cleaning. 3. The colored tape is used as the adhesive tape, and by irradiating light from an obliquely upward 360 ° direction during microscopic photography, image pre-processing is substantially unnecessary during binarization processing in the computer. Claims 1 and 2
A method for diagnosing contamination in a duct or a simple method for evaluating a duct cleaning effect according to any one of items.