Evaluation method for filter

Abstract

Provided is a method for evaluating a filter, the method being capable of evaluating filtration performance and deterioration suppression performance in real time on site, by simply performing a small amount of acquisition without using a large-scale detection device. A method for evaluating a filter for regenerating used fats and oils is provided with: an imaging step for imaging a color sample (1) together with a fats and oils filtered by a filter or a fats and oils diluted by a solvent by means of an imaging device; an image information acquisition step for acquiring image information of the captured oil or fat or fat diluted with a solvent on the basis of image information of the captured color sample (1); an oil / fat deterioration determination step for determining the state of deterioration of the oil / fat on the basis of the image information; and a filter evaluation step for evaluating the filtration performance and deterioration suppression performance of the filter on the basis of the determination results of the oil / fat deterioration determination step.

Description

Technical Field

[0001] This invention relates to an evaluation method for filters used to regenerate used lubricating oils, edible oils, and other greases. Background Technology

[0002] Cooking oil is used in various foods, but the oil used in cooking tempura, fried foods, and other deep-fried dishes oxidizes and deteriorates due to heating and storage during cooking, resulting in a decline in the taste, smell, and appearance of the food. Furthermore, oxidized and deteriorated oil has increased viscosity and poorer drainage; therefore, cooking oil that has oxidized and deteriorated to a level exceeding specified standards must be discarded. Therefore, from the perspective of protecting the environment, it is desirable to slow down the oxidation and deterioration of cooking oil as much as possible and reduce the number of times cooking oil is discarded. In addition, reducing the number of times cooking oil is discarded also has the advantages of reducing the frequency of cleaning frying utensils (deep fryers) used in deep-frying and reducing the amount of water used for cleaning.

[0003] In order to regenerate used cooking oil, various filters for edible oil filtration are used. For example, Patent Document 1 describes a filter for edible oil in which fibers such as pulp are mixed with adsorbents such as activated carbon powder in water and dehydrated by compression molding, thereby making the adsorbent uniformly dispersed.

[0004] The filtration capacity of cooking oil filters decreases with each filtration cycle, so it's necessary to determine when to replace them, usually with a specified number of uses for safety reasons. However, the degradation state of each type of cooking oil differs, resulting in varying filtration capacities for the filters. Therefore, the specified number of uses may not be suitable.

[0005] In addition, filters are used in various mechanical devices to regenerate the lubricating oil used in rotating parts and other lubrication parts, but the same problem exists.

[0006] As a method for evaluating the filtration capacity of a filter, for example, in Patent Document 2, a dispersion of metal particles is filtered with a filter, the filtrate is collected, the metal particles are dissolved in a pharmaceutical solution to prepare a solution, the solution is analyzed by ICP-MS, the amount of metal particles in the collected filtrate is detected, and the filter membrane is evaluated based on the detected amount.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent No. 4593127

[0010] Patent Document 2: Japanese Patent No. 6006541 Summary of the Invention

[0011] The technical problem that the invention aims to solve

[0012] However, the evaluation method described in Patent Document 2 requires a dispersion of metal particles and can only evaluate the collection performance of foreign matter in the filtrate. Furthermore, the evaluation requires the use of ICP-MS, which, in addition to its large equipment size, necessitates bringing the filtrate to the ICP-MS, making it impossible to immediately evaluate filtration performance.

[0013] Therefore, the purpose of this invention is to provide a method for evaluating filters that does not require large testing equipment, can be completed simply by collecting a small amount of data, and can evaluate filtration performance and degradation inhibition performance on-site in real time.

[0014] Technical means for solving problems

[0015] The above-mentioned objective of the present invention is achieved by the following [1] configuration involved in the filter evaluation method.

[0016] [1] A method for evaluating a filter, characterized in that,

[0017] It is an evaluation method for filters used to regenerate grease.

[0018] This method has the following characteristics:

[0019] The shooting process involves using a shooting device to photograph the grease filtered through the filter or the grease diluted with a solvent together with a color sample.

[0020] The image information acquisition process involves acquiring the image information of the captured color sample or the captured image information of the oil or the oil diluted with the solvent, based on the image information of the captured color sample.

[0021] The oil degradation determination process, based on the image information, determines the degradation state of the oil; and

[0022] The filter evaluation process evaluates the filtration performance and degradation inhibition performance of the filter based on the determination results of the grease degradation determination process.

[0023] Furthermore, preferred embodiments of the present invention related to the evaluation method of the filter relate to the following [2] to [6].

[0024] [2] According to the filter evaluation method described in [1],

[0025] The image information in the image information acquisition process is the RGB value of the filtered oil or the oil diluted with the solvent, and...

[0026] In the oil deterioration determination process, based on the RGB values, the brightness (ΔE) and maximum color difference defined by the following formula (1) are calculated, and the correlation between the brightness (ΔE) and the maximum color difference is determined.

[0027] Brightness (ΔE) = (R) 2 +G 2 +B 2 ) 0.5 (1)

[0028] Maximum color difference: The difference between the maximum and minimum RGB values.

[0029] [3] According to the filter evaluation method described in [2],

[0030] Following the image information acquisition process is an image information correction process, in which the white balance of the captured oil image information is corrected based on the white balance in the color sample image information.

[0031] In the grease deterioration determination process, the deterioration state of the grease is determined based on the corrected image information.

[0032] [4] According to the filter evaluation method described in [3],

[0033] The shooting device has a white balance correction function.

[0034] [5] According to the filter evaluation method described in [4],

[0035] The shooting device is a digital camera or a portable terminal with a camera.

[0036] [6] The evaluation method for filters according to any one of [1] to [5],

[0037] The grease is lubricating oil or edible oil.

[0038] Invention Effects

[0039] The filter evaluation method according to the present invention does not require large testing equipment and can be completed simply by collecting a small amount of data, enabling on-site evaluation of filtration performance and degradation inhibition performance in real time. Attached Figure Description

[0040] Figure 1 This is a top view showing an example of a color sample.

[0041] Figure 2 This is a schematic diagram showing the apparatus used in Experiment 1 and Experiment 2.

[0042] Figure 3This is a graph showing the results of the commercially available filter in Experiment 1.

[0043] Figure 4 This is a graph showing the results of the degradation suppression filter in Experiment 1.

[0044] Figure 5 This is a graph showing the results of the commercially available filter in Experiment 2.

[0045] Figure 6 This is a graph showing the results of the degradation suppression filter in Experiment 2. Detailed Implementation

[0046] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, the present invention is not limited to the embodiments described below, and can be implemented in any manner with modifications that do not depart from the spirit of the invention.

[0047] (Filming process)

[0048] In the filter evaluation method of the present invention (hereinafter referred to as the "evaluation method"), firstly, the device or equipment using grease such as lubricating oil or edible oil, such as rolling bearings, ball screw devices, or fryers, is shut down, and the grease is collected into a container and photographed together with a color sample. Various photographing devices can be used, and there are no particular limitations on their type; for example, portable terminals with cameras such as digital cameras, smartphones, and tablets can be used. Furthermore, there are no particular limitations on the type of light source used during photographing, allowing for testing in various locations.

[0049] (Image information acquisition process)

[0050] Color samples are used in this process. For example... Figure 1 As shown, color sample 1 is a list of multiple color samples 20 arranged on the surface of the backing paper 10, ranging from white (top left in the figure) to black (bottom right in the figure), with different shades and intensities. Furthermore, the image information of color sample 1 is printed on the backing paper 10 as an identification code 30. The identification code 30 may be a barcode, an illustrated QR code (registered trademark), or the like.

[0051] Then, the collected oil is placed in a petri dish, transparent bottle, or other container (not shown), and placed on the sample placement part 40 indicated by the circle in the figure. It is then photographed using various imaging devices along with color sample 1. Here, the amount of oil collected is only about 10 mg, which is a very small amount. Furthermore, the oil can be oil alone or diluted with a solvent. As for the solvent, there are no particular limitations as long as it is colorless and transparent enough to easily mix with the oil and not interfere with the color of the oil during photography. Specifically, organic solvents, kerosene-based solvents, and gasoline-based solvents are preferred. It should be noted that by diluting the oil with a solvent, it is possible to classify oils that have changed color to a darker, especially black, degree.

[0052] (Image information correction process)

[0053] The captured image information of the grease is compared with the image information of color sample 1. At this point, it is preferable to correct the white balance in the captured image information of the grease. By correcting the white balance, the captured image information of the grease can more appropriately match the image information of color sample 1, regardless of the environment of the shooting location (i.e., the testing location) which may be affected by factors such as brightness.

[0054] Furthermore, if the shooting device used has a white balance correction function, the aforementioned white balance correction can be performed through that function. Alternatively, the image information obtained by the shooting device can be sent to an external processing device such as a server, and the white balance correction can be performed through the white balance correction function of that processing device. Additionally, the comparison between the image information of the lubricant and the image information of color sample 1, described later, can be performed within the shooting device or in an external processing device.

[0055] (Oil and grease deterioration assessment process)

[0056] Next, the hue of the image of the oil after white balance correction (hereinafter referred to as the "corrected image") is determined. The hue is represented by three colors: red (R), green (G), and blue (B), and the brightness (ΔE) is determined based on the RGB values ​​of the corrected image according to the following formula (1).

[0057] Brightness (ΔE) = (R) 2 +G 2 +B 2 ) 0.5 (1)

[0058] Additionally, the difference between the maximum and minimum values ​​in the RGB values ​​is set as the maximum color difference for lubricant-corrected images.

[0059] As shown in the experimental examples described later, data was collected at predetermined filtration times or after a certain number of filtrations. The brightness (ΔE) and maximum color difference were calculated. When the brightness (ΔE) was plotted on the X-axis and the maximum color difference on the Y-axis, a semi-circular correlation was observed. Based on this graph, the deterioration status (deterioration state) of the collected oil was determined.

[0060] Furthermore, when the oil is diluted, the shooting device and server can be equipped with a calibration function, and calibration can be performed according to the dilution rate using a pre-made calibration table, etc.

[0061] (Filter evaluation process)

[0062] Then, based on the deterioration state of the grease, the filtration performance and deterioration inhibition effect of the filter are evaluated.

[0063] Example

[0064] The present invention will be made clearer by providing examples and comparative examples below.

[0065] <Experiment 1: Evaluation during continuous filtration>

[0066] As a comparative example, a commercially available filter was prepared; as an example, a degradation inhibition filter was prepared. The degradation inhibition filter was coated with an antioxidant to inhibit oil degradation.

[0067] Install each filter on Figure 2 The apparatus shown is used to investigate the deterioration state of rapeseed oil. The apparatus includes: an oil tank 51 for storing rapeseed oil 50, an annular pipe 52 for flowing rapeseed oil 50, a pump 54 for transporting rapeseed oil 50, and a processing unit 53 containing a filter. The rapeseed oil 50 in the oil tank 51 is transported through the pipe 52 by the pump 54, filtered in the processing unit 53, and then returned to the oil tank 51.

[0068] Then, rapeseed oil 50 was heated to 180℃ while being continuously filtered. After 24 hours, 48 ​​hours, and 96 hours, the filtered rapeseed oil 50 was collected. The collection amount was set to 1g each time.

[0069] The collected rapeseed oil was placed in a petri dish and placed on a plate. Figure 1 The sample placement unit 40 for color sample 1 shown is used to photograph the collected rapeseed oil and color sample together with a digital camera with white balance correction function, and the RGB values ​​are obtained from the corrected image. Then, based on the obtained RGB values, the luminance (ΔE) and maximum color difference are calculated based on equation (1), and a graph is created with luminance (ΔE) as the horizontal axis and maximum color difference as the vertical axis.

[0070] The graph representing the brightness (ΔE) and maximum color difference at various filtration times when using a commercially available filter is shown in the figure. Figure 3 In addition, a graph showing the brightness (ΔE) and maximum color difference at each filtration time when using a degradation suppression filter is presented in [the figure]. Figure 4 As shown in the figure, when the rapeseed oil was new, it was almost colorless and had high brightness. However, as filtration time progressed, it was observed that the filtered rapeseed oil deteriorated and turned brown, resulting in a decrease in brightness and an increase in maximum color difference due to a reduction in blue. Furthermore, after 96 hours of filtration, a comparison between the commercially available filter and the degradation-inhibiting filter revealed that the rapeseed oil filtered using the commercial filter had lower brightness (ΔE) and lower maximum color difference compared to the rapeseed oil filtered using the degradation-inhibiting filter, indicating accelerated degradation.

[0071] <Experiment 2: Evaluation of Filtration Times>

[0072] Use commercially available filters and degradation inhibitor filters to filter the degraded rapeseed oil. At this point, simply allow the oil to flow through the filters; do not use [other filters]. Figure 2 The apparatus was then used. The rapeseed oil was then filtered once or three times, and the color change after filtration was observed. The sample size was also set to 1g each time.

[0073] The hue measurement was performed in the same manner as in Experiment 1. The luminance (ΔE) and maximum color difference were calculated from the obtained RGB values, and a graph was created with luminance (ΔE) on the horizontal axis and maximum color difference on the vertical axis. The graph showing the luminance (ΔE) and maximum color difference for each filtration cycle using a commercially available filter is presented below. Figure 5 The graph representing the brightness (ΔE) and maximum color difference for each filtration cycle using the degradation suppression filter is shown in [the figure]. Figure 6 It should be noted that, Figure 5 and Figure 6 The "inferior quality" in the text refers to the measurement value of rapeseed oil that has never been filtered.

[0074] As shown in the figure, the rapeseed oil from both filters was almost colorless and had high brightness when new. However, with increasing filtration cycles, the filtered rapeseed oil deteriorated and turned brownish, thus reducing its brightness. Furthermore, comparing a commercially available filter and a degradation-inhibiting filter after three filtrations revealed that the rapeseed oil filtered with the degradation-inhibiting filter exhibited a larger maximum color difference, indicating that degradation was effectively suppressed.

[0075] The color changes shown in Experiments 1 and 2 are difficult to confirm visually, making it difficult to determine the deterioration state of the filter. However, the evaluation method of this invention can be used to evaluate it with high precision.

[0076] The various embodiments have been described above, but the present invention is not limited to these examples. It will be apparent to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these modifications or alterations are also within the technical scope of the present invention. Furthermore, the constituent elements of the above embodiments can be combined arbitrarily without departing from the spirit of the invention.

[0077] Furthermore, this application is based on Japanese Patent Application No. 2023-014037, filed on February 1, 2023, the contents of which are incorporated herein by reference.

[0078] Explanation of reference numerals in the attached figures

[0079] 1 Color Sample

[0080] 10 backing paper

[0081] 20 color samples

[0082] 30 Identification Code

[0083] 40 Sample placement section

[0084] 50 rapeseed oil

[0085] 51 Oil tank

[0086] 52 Piping

[0087] 53 Processing Department

[0088] 54 pumps

Claims

1. A method for evaluating filters, characterized in that, It is an evaluation method for filters used to regenerate grease. The evaluation method has the following characteristics: The shooting process involves using a shooting device to photograph the grease filtered through the filter or the grease diluted with a solvent together with a color sample. The image information acquisition process involves acquiring the image information of the captured color sample or the captured image information of the oil or the oil diluted with the solvent, based on the image information of the captured color sample. The oil degradation determination process determines the degradation state of the oil based on the image information. as well as The filter evaluation process evaluates the filtration performance and degradation inhibition performance of the filter based on the determination results of the grease degradation determination process.

2. The filter evaluation method according to claim 1, characterized in that, The image information in the image information acquisition process is the RGB value of the filtered oil or the oil diluted with the solvent, and... In the grease deterioration determination process, based on the RGB values, the brightness (ΔE) and maximum color difference defined by the following formula (1) are calculated, and the correlation between the brightness (ΔE) and the maximum color difference is determined. Brightness (ΔE) = (R) 2 +G 2 +B 2 ) 0.5 (1) Maximum color difference: The difference between the maximum and minimum RGB values.

3. The filter evaluation method according to claim 2, characterized in that, Following the image information acquisition process is an image information correction process, in which the white balance of the captured oil image information is corrected based on the white balance in the color sample image information. In the grease deterioration determination process, the deterioration state of the grease is determined based on the corrected image information.

4. The filter evaluation method according to claim 3, characterized in that, The shooting device has a white balance correction function.

5. The filter evaluation method according to claim 4, characterized in that, The shooting device is a digital camera or a portable terminal with a camera.

6. The method for evaluating a filter according to any one of claims 1 to 5, characterized in that, The grease is lubricating oil or edible oil.

Images