JP2004105874A - Method and equipment for manufacturing hollow fiber membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and equipment in which whether or not an impassable fiber is generated and how many impassable fibers are generated can be known and whether a hollow fiber membrane module is good or bad can be correctly decided when the hollow fiber membrane module is manufactured. <P>SOLUTION: The image of the potting end face of the hollow fiber membrane module to be tested is picked up. The picked-up image is binarized by a portion of hollow fiber membranes and another portion. The average value of luminances of the hollow portions of the hollow fiber membranes is calculated and the calculated average value is compared with a predetermined threshold. When the average value exceeds the threshold, it is decided that the hollow fiber membrane module to be tested contains impassable fibers. When the number of the impermeable fibers exceeds the predetermined threshold, it is decided that the hollow fiber membrane module to be tested is a defective product. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing a hollow fiber membrane module that can be used for an artificial dialyzer, a wastewater treatment device, a water purifier, and the like.
[0002]
[Prior art]
As is well known, for example, a hollow fiber membrane module stores a yarn bundle of a hollow fiber membrane (hollow semi-permeable membrane) having both ends opened in a container having both ends or one end opened, and At both ends, the gap between the container and the hollow fiber membrane is sealed with a resin. The sealing with the resin is performed by pouring (potting) the resin into a space between the container and the yarn bundle and allowing the potting resin to penetrate around each hollow fiber membrane. Potting resin may enter inside and the hollow fiber membrane may be closed. The closed hollow fiber membrane becomes a so-called impervious thread. When such impervious thread is present, for example, in the case of an artificial dialyzer, blood flowing into the hollow fiber membrane remains in the hollow fiber membrane, and the dialysis performance is reduced. And if it is significant, sufficient artificial dialysis cannot be performed. Therefore, it is necessary to remove a hollow fiber membrane module in which a certain number or more of non-threaded yarns exist from the production line as a defective product.
[0003]
By the way, conventionally, the determination of the quality of a hollow fiber membrane module related to the occurrence of a non-threaded yarn is based on the fact that the occurrence of the non-threaded yarn is correlated with a group of minute bubbles generated in the potting resin due to improper potting. According to the concept, the potting end face is imaged by a CCD camera, and a bubble group is detected (for example, see Patent Document 1).
[0004]
[Patent Document 1]
However, such a conventional technology detects the presence or absence of minute air bubbles in the potting resin and does not directly detect the presence or absence of a non-threaded yarn. I can't tell you. In addition, since there is not always a correlation between the occurrence of the non-through yarn and the occurrence of the bubble group, a problem remains in terms of accuracy.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a method and an apparatus capable of knowing whether or not an impervious yarn has occurred and the degree of its occurrence in producing a hollow fiber membrane, and accurately determining the quality.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an image of a potting end face of a hollow fiber membrane module to be tested, binarizes the obtained image between a hollow fiber membrane part and other parts, and performs hollow processing. The average value of the brightness of the hollow portion of the fiber membrane is obtained, and the average value of the brightness is compared with a predetermined threshold. When the average value of the brightness exceeds the threshold value, the hollow fiber membrane is determined to be non-threaded and the non-threaded thread is determined. When the number of hollow fiber membranes determined to exceed a predetermined threshold value, the hollow fiber membrane module to be tested is determined to be defective. It is also preferable to irradiate light to the potting end face of the test hollow fiber membrane module and to image scattered light from the potting end face. In that case, it is preferable that the light is light in the ultraviolet band, which is also light having a single wavelength.
[0007]
Further, in order to achieve the above object, the present invention provides an imaging means for a potting end face of a hollow fiber membrane module to be tested, and an image obtained by this imaging means is divided into a hollow fiber membrane portion and other portions. Means for performing binarization processing, means for obtaining an average value of the brightness of the hollow portion of the hollow fiber membrane and comparing the average value of the brightness with a predetermined threshold value, and means for determining the average value of the brightness when the average value exceeds the threshold value Means for judging the test hollow fiber membrane module as defective when the number of hollow fiber membranes judged to be non-threaded and the number of hollow fiber membranes judged to be non-threaded exceeds a predetermined threshold value. An apparatus for manufacturing a hollow fiber membrane module is provided. It is also preferable to provide a light irradiating means for irradiating the potting end face of the test hollow fiber membrane module with light. In that case, the light irradiation means preferably includes a low-pressure mercury lamp. Preferably, the imaging means is a line sensor camera.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
In FIG. 1, a manufacturing apparatus of a hollow fiber membrane module includes a measuring table 1 having a module supporting means 1a and a module moving means 1b, a module transferring apparatus 2, and a light irradiation apparatus 3 having a light source 3a and a power supply 3b. , An imaging device 4, an image processing device 5, an operation command device 6, and a display device 7. Hereinafter, the configuration of each of these units will be described in detail together with the operation thereof.
Measuring table 1:
The module supporting means 1a supports a sample hollow fiber membrane module M (hereinafter, referred to as a module) carried by a module transfer device 2 described later, and adjusts the inclination of the hollow fiber membrane module M. By moving the position of the module M up, down, left and right in accordance with the size of the module M, that is, the outer diameter and length, the center of the potting end face of the module M can be made to coincide with the optical center of the imaging device 4 described later. It has become. In this embodiment, since a line sensor camera is used as the imaging device 4, the module moving means 1b is provided so that the module M can be moved at a predetermined speed in the horizontal direction.
Light irradiation device 3:
The light irradiation device 3 includes a light source 3a and a power supply 3b. In this embodiment, a ring-shaped low-pressure mercury lamp that generates near ultraviolet light having a wavelength of 368 nm is used as the light source 3a. It is preferable to use a light source having a wavelength in the ultraviolet band and a single wavelength in order to obtain a clear image of the potting end face. The power supply 3b turns on / off the light source 3a and adjusts the amount of light according to a command from an operation command device 6 described later.
Imaging device 4:
The imaging device 4 is for capturing an image of a potting end surface of the module M on the measurement table 1 and obtaining an image. In this embodiment, a 5,000 pixel line sensor camera is used.
Image processing device 5:
The image processing device 5 processes the image of the potting end face of the module M photographed by the imaging device 4 and determines the presence or absence of a thread break and the quality of the module M. The flow of the processing by the image processing device 5 is as shown in FIG.
[0009]
In FIG. 2, the high-pass filter pre-processes the image sent from the imaging device 4 so that the thick region of the hollow fiber membrane is emphasized.
[0010]
Next, the preprocessed image is binarized by a predetermined threshold value, and the thick part of the hollow fiber membrane is a white pixel, and the hollow part and the potting resin part of the hollow fiber membrane are black pixels of a black pixel. And
[0011]
Next, a labeling process for labeling a black pixel region within an arbitrary area is performed. The pattern subjected to the labeling process includes a hollow fiber membrane pattern which is a hollow portion of the hollow fiber membrane, and a pseudo pattern in which a potting resin portion surrounded by a plurality of hollow fiber membranes is recognized as one region. In the index value calculation, in order to classify these patterns into a circular pattern and a non-circular pattern, the ratio α between the long side D and the short side L when the long side of the rectangle circumscribing the pattern is the maximum,
α = D / L (1)
And the area β calculated from the area A of the pattern and the perimeter ρ assuming that the pattern is a perfect circle,
β = B / A = (ρ × ρ) / 4πA (2)
Are calculated for the two roundness determinations.
[0012]
In the classification, with respect to the four index values of L, D, α, and β, a pattern that exceeds a set threshold value is a circular pattern, and a pattern that falls below any one of the index values is a non-circular pattern. Do. When the pattern is a perfect circle, both the index values α and β are 1 as follows.
[0013]
α: In the case of a perfect circle, α = 1 because L = D
β: In the case of a perfect circle, A = 1 and therefore β = 1
Next, a process of removing the pseudo pattern is performed. Since the pseudo pattern occurs in the potting resin portion surrounded by the plurality of hollow fiber membranes, the relationship between the distance D1 from the outer periphery of the circular pattern and the distance D2 between the hollow portions of the hollow fiber membrane is as follows. .
[0014]
D2 / 2 ≦ D1 ≦ D2 (3)
Therefore, the pseudo pattern is removed from the inspection target by utilizing the difference between the distance D1 from the hollow fiber membrane pattern to the pseudo pattern and the distance D2 to the non-circular hollow fiber membrane pattern.
[0015]
In this process, first, only a pattern with high roundness (hereinafter, referred to as a circular pattern) is extracted from the pattern image based on the values of α and β, and a distribution image including only the circular pattern is created. Next, for this image, expansion processing is performed to enlarge the area of the circular pattern by a predetermined distance from the outer periphery of the circular pattern, and thereafter, the circular pattern is subtracted from the expanded distance by the thickness of the hollow fiber membrane. Is performed to reduce the area of. As a result, the area where there is no hollow fiber membrane is filled with white pixels created by the expansion and contraction of the circular pattern, while the area farther than the expanded distance remains a black pixel. An image is created. In this distance mask image, a white pixel portion is a region where a pattern classified as a circular pattern and a pseudo pattern exist, and a black pixel portion is a region where a non-circular hollow fiber membrane pattern other than the circular pattern can exist. Then, when the distance mask image and the pattern image are overlapped and the pattern image overlapping the white pixel portion of the distance mask image is removed, the pseudo pattern is deleted and only the hollow fiber membrane pattern other than the circle remains. When the logical sum of the hollow fiber membrane pattern image and the circular pattern image is calculated, a hollow part pattern image of the hollow fiber membrane in which only the hollow part of the hollow fiber membrane including the circle and the non-circle is a white pixel is obtained. Therefore, a logical operation is performed on the hollow portion pattern image and the captured image, and a hollow fiber membrane pattern portion in the captured image is specified. That is, an image representing only the hollow portion of the hollow fiber membrane is created.
[0016]
Next, the position information of the hollow portion is obtained from all the hollow portions included in the image, and the hollow portion brightness average value of the hollow fiber membrane is obtained from the captured image based on the position information. When the average brightness value exceeds a predetermined threshold value, the hollow fiber membrane is determined to be impervious.
[0017]
Finally, the module M is determined. If the number of non-threaded yarns does not exceed a predetermined threshold value, it is determined to be a non-defective product.
Operation command device 6:
The operation command device 6 responds to the difference in the outer diameter of the module M, the outer diameter and the inner diameter of the hollow fiber membrane, the assembling method, etc., sends a command to the image processing device 5, and outputs an index suitable for the module M to be inspected. In addition to setting a value, a binarization threshold, a coefficient of a high-pass filter, and the like, a command is sent to the power supply 3b of the light irradiation device 3 to turn on / off the light source 3a and adjust the light amount. Further, a command is sent to the module supporting device 1 to control the module moving device 1b so that the module M moves at a speed suitable for photographing by the imaging device 4.
Display device 7:
The display device 7 displays an inspection result in which an unthreaded portion is marked in an image.
Module transfer device 2:
The module transfer device 2 mounts the module M on the support device 1a. After the inspection is completed, the module M is transferred to a subsequent process when it is determined that the module M is non-defective, and is removed from the production line when it is determined that the module M is defective, according to a command from the operation command device 6.
[0018]
Now, in order to explain the present invention in more detail based on a more specific example, FIG. 3 is an image of a potting end face of the module M taken by the imaging device 4. When this image is subjected to a differential filter by the image processing device 5 and subjected to a binarization process at a predetermined threshold value, a binarized image shown in FIG. 4 is obtained. In this example, there are 529 small patterns of black pixels to be inspected, each having an area of 20 to 200 pixels, of which 471 patterns are determined to be close to a perfect circle as a result of the roundness measurement of the patterns. Was. FIG. 5 shows a circular pattern image obtained by extracting only a pattern close to a perfect circle. When the white pixel area is expanded by 9 pixels and then contracted by 6 pixels, the distance mask image shown in FIG. 6 is obtained.
[0019]
Next, the non-circular pattern image shown in FIG. 7 and the distance mask image shown in FIG. 6 are superimposed. If the non-circular pattern in the image in FIG. When the logical OR processing for removal is performed, a non-circular hollow fiber membrane pattern image as shown in FIG. 8 is obtained.
[0020]
Next, based on the positional information of the hollow fiber membrane pattern image shown in FIG. 9, which is the logical sum of the image shown in FIG. 5 and the image shown in FIG. When the luminance value is obtained and compared with a predetermined threshold value, an image shown in FIG. 10 is obtained in which only the hollow fiber patterns exceeding the threshold value are marked. In this example, 51 hollow fiber membranes were determined to be impervious.
Next, when comparing the number of hollow fiber membranes determined to be non-threaded with the threshold value (30 in this example) for defective products of the module M, the number of non-threaded yarns exceeds the threshold. M was determined to be defective and was removed from the manufacturing process.
[0021]
The method for manufacturing a hollow fiber membrane module according to the present invention can be applied to the case of manufacturing a hollow fiber membrane module such as an artificial dialyzer, a sewage treatment device, and a water purifier used in ordinary households.
[0022]
【The invention's effect】
The present invention captures an image of a potting end face of a hollow fiber membrane module to be tested, binarizes the obtained image between a hollow fiber membrane part and other parts, and obtains brightness of a hollow part of the hollow fiber membrane. The average value is obtained and the average value of the luminance is compared with a predetermined threshold value.When the average value of the luminance exceeds the threshold value, the hollow fiber membrane is determined to be non-filament and the hollow fiber membrane determined to be non-filament is determined. When the number exceeds a predetermined threshold value, the hollow fiber membrane module to be tested is determined to be defective, and is determined based on indirect information such as the presence or absence of microbubble groups in the potting resin as in the conventional technology. Therefore, the quality can be accurately determined.
[Brief description of the drawings]
FIG. 1 is a schematic front view of an apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a processing flow in an image processing apparatus of the apparatus shown in FIG.
FIG. 3 is an image of a potting end face taken by the apparatus shown in FIG. 1;
FIG. 4 is a binarized image of the image shown in FIG.
5 is a pattern image determined to be a hollow portion of a hollow fiber membrane close to a perfect circle from a roundness measurement of a black pixel region in the image shown in FIG. 4;
6 is a distance mask image obtained by subjecting the image shown in FIG. 5 to expansion and contraction processing.
FIG. 7 is an image of a pattern that is not determined to be close to a perfect circle in the black pixel region in the image shown in FIG. 4;
FIG. 8 is an image of a pattern of a hollow portion of a hollow fiber membrane determined to be not a perfect circle, based on a logical sum of the images shown in FIGS. 6 and 7.
FIG. 9 is an image of a pattern determined to be a hollow portion of a hollow fiber membrane based on a logical sum of the images shown in FIGS. 5 and 8.
10 is an image showing only a pattern in which an average luminance value of an area corresponding to the pattern area shown in FIG. 9 exceeds a predetermined threshold value in the image shown in FIG. 3;
[Explanation of symbols]
M: hollow fiber membrane module to be tested 1: measuring table 1a: module supporting means 1b: module moving means 2: module transfer device 3: light irradiation device 3a: light source 3b: power supply 4: imaging device 5: image processing device 6 : Operation command device 7: Display device

Claims (9)

The potting end face of the hollow fiber membrane module to be tested is imaged, and the obtained image is binarized between the hollow fiber membrane part and the other parts, and the average brightness value of the hollow part of the hollow fiber membrane is obtained. The average value of the brightness is compared with a predetermined threshold value, and when the average value of the brightness exceeds the threshold value, the hollow fiber membrane is determined to be non-threaded and the number of hollow fiber membranes determined to be non-threaded is determined in advance. A hollow fiber membrane module to be tested is determined to be defective when the threshold value is exceeded. The method for producing a hollow fiber membrane module according to claim 1, wherein the potting end face of the test hollow fiber membrane module is irradiated with light and scattered light from the potting end face is imaged. The method for manufacturing a hollow fiber membrane module according to claim 2, wherein the potting end face is irradiated with light in an ultraviolet band. The method for manufacturing a hollow fiber membrane module according to claim 2, wherein the potting end face is irradiated with light having a single wavelength. Imaging means for the potting end face of the hollow fiber membrane module to be tested, means for binarizing an image obtained by the imaging means between the hollow fiber membrane part and the other part, and the hollow part of the hollow fiber membrane Means for determining the average value of the luminance and comparing the average value of the luminance with a predetermined threshold, and when the average value of the luminance exceeds the threshold, the hollow fiber membrane is determined to be non-threaded and determined to be non-threaded. Means for determining that the hollow fiber membrane module to be tested is defective when the number of hollow fiber membranes exceeds a predetermined threshold value. The apparatus for manufacturing a hollow fiber membrane module according to claim 5, further comprising a light irradiating means for irradiating light to a potting end surface of the test hollow fiber membrane module. The apparatus for manufacturing a hollow fiber membrane module according to claim 6, wherein the light irradiation means includes a low-pressure mercury lamp. The apparatus for manufacturing a hollow fiber membrane module according to claim 5 or 6, wherein the imaging means is a line sensor camera. A hollow fiber membrane module manufactured using the method according to any one of claims 1 to 4 or the apparatus according to any one of claims 5 to 8.

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