JP2009284883A - Apparatus for washing agricultural product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for washing agricultural products, which removes a residual agrochemical including a sparingly-water-soluble agrochemical adhered to agricultural products even if water is used as a washing solvent. <P>SOLUTION: The apparatus 1 for washing agricultural products in the embodiment is equipped with a case body 10, a water tank 12 arranged on the upper part of the case body 10, an ultrasonic vibration part 15 composed of a plurality of ultrasonic vibrators for ultrasonically vibrating washing water in the water tank 12, a netlike cleaning basket 30 that retains agricultural products inside and is arranged in the water tank 12 and a control part 40 for controlling the whole washing apparatus 1. The control part 40 vibrates the ultrasonic vibration part 15 in a frequency of 40-150 kHz, generates radicals in the washing water and controls ultrasonic washing of agricultural products. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a crop cleaning apparatus for cleaning crops, and more particularly to a crop cleaning apparatus suitable for removing residual agricultural chemicals adhering to a crop.

  In recent years, interest in food safety and security has increased, but since the positive list system (a system that basically prohibits the distribution of food containing a certain amount of pesticides etc. for which no standard has been established) has been imported Regardless of the product or domestic product, there are many cases where the agricultural chemical residual pesticide exceeds the standard value.

  For this reason, it is desirable to remove residual agricultural chemicals that have adhered to the crops to a safe level below the reference value, but methods such as brushing cleaning that directly rubs the crops will damage the surface of the crops. In the case of crops with a complex surface shape, scrubbing itself is difficult.

In view of such a problem, Patent Document 1 below discloses a method in which a cleaning liquid is ultrasonically vibrated in a state where agricultural products are immersed in a cleaning liquid in a container, and residual agricultural chemicals are removed by ultrasonic cleaning.
JP 2004-321021 A

  On the other hand, there are hundreds of kinds of pesticides, ranging from easily water-soluble to slightly water-soluble. In order to remove such various agricultural chemicals, in the above-mentioned Patent Document 1, a washing liquid (solvent) in which agricultural products are immersed is obtained by adding a neutral detergent to water.

  However, the use of water with a neutral detergent added as a washing solvent as in Patent Document 1 is not preferable because the neutral detergent adheres to the washed crops. Further, in order to ensure safety and security, a separate process for washing away the neutral detergent is required.

  The present invention has been made to solve the above problems, and even when water is used as a cleaning solvent, it is possible to remove residual agricultural chemicals attached to agricultural crops, including poorly water-soluble agricultural chemicals. An object of the present invention is to provide a simple crop cleaning apparatus.

  In order to solve the above-described problems, a crop cleaning apparatus according to the present invention is a crop cleaning apparatus for cleaning crops, wherein a tank for storing cleaning water in which crops are immersed, a tank installed around the tank, and the tank An ultrasonic vibration unit that ultrasonically vibrates the cleaning water, and a control unit that controls the ultrasonic vibration unit, wherein the control unit vibrates the ultrasonic vibration unit at a frequency of 40 to 150 kHz. And controlling to ultrasonically wash the crops by generating radicals in the washing water.

  The crop cleaning method according to the present invention includes a step of immersing the crop in the cleaning water in the crop cleaning method for cleaning the crop to remove residual agricultural chemicals, and ultrasonic vibration of the cleaning water at a frequency of 40 to 150 kHz. And a step of ultrasonically cleaning the crop by generating radicals in the washing water.

  According to the crop cleaning apparatus of the present invention, even when water is used as a cleaning solvent, it is possible to remove residual pesticides adhering to crops, including poorly water-soluble pesticides, to a sufficiently safe level. is there.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an image diagram schematically illustrating a configuration of a crop cleaning apparatus according to the present embodiment. As shown in the figure, the crop cleaning apparatus 1 according to the present embodiment includes a housing 10, a water tank 12 installed on the top of the housing 10, and a plurality of ultrasonic vibrations for the cleaning water in the water tank 12. An ultrasonic vibration unit 15 composed of an ultrasonic vibrator, a net-like washing basket 30 that holds a farm product inside and is installed in the water tank 12, and a control unit 40 that controls the entire cleaning device 1. .

  In the water tank 12, a net-like metal washing basket 30 for storing the crops 50 such as vegetables and fruits to be washed therein and immersing them in the washing water is detachably installed. Further, the water tank 12 has a water supply port 20 for supplying cleaning water into the water tank 12, a drain port 25 for draining the cleaning water in the water tank 12, and the cleaning water stored in the water tank 12 at a predetermined water level. An overflow drain port 28 for overflow drainage is provided so as not to become above.

  FIG. 2 is a plan view of the water tank 12 and shows the installation positions of the water supply port 20, the drain port 25, and the overflow drain port 28. As shown in FIG. 1, the water supply port 20 is a lower part on the left side of the water tank 12 in the drawing, and is installed at a position on the near side as shown in FIG. 2. Further, an ejector-type microbubble generating nozzle 21 is connected to the water supply port 20, and microbubbles can be supplied into the water tank 12 from the water supply port 20 together with water supply.

  The micro-bubble generating nozzle 21 is connected to a water supply line via a water supply valve 22, takes in air taken in through an air inlet 23 into the water to be injected, and has several tens to several hundreds of microns in the wash water. Generate microbubbles. In this embodiment, water is used as the cleaning water.

  As shown in FIG. 1, the drainage port 25 is a bottom surface on the right side of the water tank 12 in the drawing, and is installed on the back side as shown in FIG. 2. Further, the drain port 25 is connected to the drain line via the water level control valve 26, and the water level and drainage of the washing water in the water tank 12 can be controlled by opening and closing the water level control valve 26 under the control of the control unit 40. It is configured.

  As shown in FIG. 1, the overflow drain port 28 is an upper part on the left side of the water tank 12 in the drawing, and is installed on the back side as shown in FIG. 2. As described above, since the water supply port 20 is installed at the lower left front portion of the lower portion, when water is supplied, a counterclockwise water flow is generated as indicated by an arrow in FIG. And since the overflow drain port 28 is installed in the upper left part on the upper left side, when the washing water is filled in the water tank 12 and the overflow water is discharged, the water flow rising while rotating counterclockwise is generated. Occurs within.

  The ultrasonic vibration unit 15 is configured by arranging twelve circular ultrasonic transducers, and each transducer is ultrasonically vibrated at a predetermined frequency under the control of the control unit 40. The crop cleaning apparatus 1 according to the present embodiment is characterized in that residual agricultural chemicals attached to the crop 50 are removed by ultrasonic cleaning using a predetermined frequency.

  Here, the vibration frequency of the ultrasonic vibration unit 15 according to the present embodiment will be described in detail. There are many pesticides with poor water solubility (similar to oil), and when water is used as a cleaning solvent, these poorly water-soluble pesticides cannot be easily removed. On the other hand, the present inventor has found through experiments that a poorly water-soluble pesticide can be removed by generating radicals in the wash water by ultrasonically vibrating the wash water at a predetermined frequency.

  This is because hydroxyl radicals (OH radicals), which are free radicals, are generated by ultrasonic vibration of water at a predetermined frequency, and these highly reactive hydroxyl radicals attack residual pesticides, resulting in poorly water-soluble residues. This is thought to be because a hydrophilic group is formed in the pesticide and is easily dissolved in water.

  Therefore, in order to confirm in which frequency band the radicals are generated, the present inventor 1 performs an experiment 1 in which each hydrogen peroxide generation amount [ppb] is measured when ultrasonic waves having a plurality of frequencies are irradiated on water. Went. Table 1 below shows the experimental results of Experiment 1. Since radicals are unstable and have a short lifetime, it is difficult to measure directly. Therefore, in Experiment 1, the amount of generated hydroxyl radicals is indirectly measured by measuring the amount of hydrogen peroxide generated by combining two hydroxyl radicals.

In Experiment 1, hydrogen peroxide when the frequency is 25 kHz, 40 kHz, 45 kHz, 60 kHz, 75 kHz and 100 kHz and the ultrasonic intensity of 0.5 W / cm ² is irradiated for 10 minutes, 30 minutes and 60 minutes, respectively. Is measured. As shown in Table 1, hydrogen peroxide is not generated at 25 kHz, but hydrogen peroxide is generated at 40 kHz or higher, and the generated amount increases as the frequency becomes higher than 40 kHz. Therefore, when considering only removal of poorly water-soluble residual agricultural chemicals, it is desirable to radiate ultrasonic waves of at least 40 kHz or more.

  On the other hand, if only the readily water-soluble pesticides are washed away, it is sufficient to generate a lot of cavitation, and the frequency suitable for generating cavitation is assumed to be different from the frequency suitable for generating the radical. Is done.

  Therefore, in order to obtain a frequency suitable for removing both the water-soluble residual agricultural chemical and the poorly water-soluble residual agricultural chemical, the present inventor Then, Experiment 2 was performed to determine the agrochemical removal rate [%] at each frequency when cleaning was performed by irradiation with ultrasonic waves of a plurality of frequencies. Table 2 below shows the experimental results of Experiment 2.

In Experiment 2, a model test was actually performed. The agricultural chemicals dipped in diluted agricultural chemicals were analyzed before and after cleaning, and the removal rate was calculated from the concentration change. Also, in Experiment 2, the pesticide removal rate was determined when the frequency was 20 kHz, 25 kHz, 38 kHz, 45 kHz, 60 kHz, 75 kHz, 100 kHz and 150 kHz and ultrasonic waves with an ultrasonic intensity of 0.75 W / cm ² were irradiated for 10 minutes. Yes.

  In Experiment 2, strawberry and tomato were used as crops, acetamiprid (strawberry) as a water-soluble pesticide, chlorothalonil (tomato) and azoxystrobin (strawberry) as a water-soluble pesticide, poorly water-soluble pesticide Pyridalil (strawberry) was used.

  As shown in Table 2, the readily water-soluble pesticide is well removed in all frequency bands, but shows a higher removal rate at relatively low frequencies such as 25 kHz and 38 kHz. Medium water-soluble pesticides are also well removed in all frequency bands, but show higher removal rates at intermediate frequencies such as 38kHz, 45kHz and 60kHz. In addition, poorly water-soluble pesticides are removed only in a frequency band higher than 38 kHz where radicals are generated, and show a higher removal rate at relatively high frequencies such as 100 kHz and 150 kHz.

  In view of the results of Experiment 1 and Experiment 2, in order to achieve removal of easily water-soluble and medium water-soluble agricultural chemicals while removing poorly water-soluble agricultural chemicals, the frequency band exceeding 40 to 150 kHz is generated. It is desirable to perform ultrasonic cleaning using sound waves.

The configuration of the crop cleaning apparatus according to the present embodiment has been described in detail above. Next, cleaning example 1 that is an example of a cleaning method using the crop cleaning apparatus will be described.
(1) Cleaning example 1
In this cleaning example 1, the agricultural products are ultrasonically cleaned by irradiating ultrasonic waves of a predetermined frequency, for example, 40 kHz, selected from 40 to 150 kHz which is a frequency band where radicals are generated.

  Specifically, under the control of the control unit 40, water containing microbubbles is supplied from the water supply port 20 into the aquarium 12, and the washing basket 30 storing the crop 50 that is the object to be washed is placed in the aquarium 12. Install. When the water level of the cleaning water reaches the level of the overflow drain port 28, the overflow is drained from the overflow drain port 28.

  Then, by driving the ultrasonic vibration unit 15 at 40 kHz, for example, ultrasonic cleaning is performed for 10 minutes while irradiating the cleaning water with 40 kHz ultrasonic waves, and the cleaning ends. During this time, water supply continues and drainage due to overflow continues.

  According to this cleaning example 1, since ultrasonic cleaning is performed by irradiating 40 kHz ultrasonic waves, as described above, radicals are generated to dissolve the poorly water-soluble pesticides in water, and the water-soluble and Pesticides can be removed from crops, including moderately water-soluble pesticides.

  Further, in this cleaning example 1, since water containing microbubbles of several tens to several hundreds of microns is supplied from the water supply port 20 by the microbubble generation nozzle 21, more microscopic cavitation is generated in addition to generation of cavitation by ultrasonic waves. Since bubbles are generated, it is possible to remove more dirt (residual agricultural chemicals, etc.) adhering to the crop. Since the surface of the crop has irregularities on the order of microns and has a complicated shape, microbubbles and nanobubbles are necessary, and precise cleaning on the order of microns using an ultrasonic cavity is necessary.

  Further, in this cleaning example 1, the water supply and the overflow drainage are continued even during the cleaning, and the cleaning water supplied from the water supply port 20 provided in the lower part of the water tank 12 is provided in the upper part of the water tank 12 at a remote position. It is moved to the overflow outlet 28 and drained. Therefore, the pesticide removed from the agricultural product 50 can be discharged from the overflow drain 28 without staying in the water tank 12, and the soaking of the washing water is prevented more efficiently by so-called rinsing, thereby removing the remaining pesticide more efficiently. It can be carried out.

  Of course, in the cleaning example 1, the cleaning frequency can be appropriately changed between 40 to 150 kHz, and the cleaning time can also be appropriately changed. Even when the water supply from the water supply port 20 is normal water supply that does not generate microbubbles, or even when the water supply is stopped during washing so as not to overflow, the remaining pesticide can be sufficiently removed. It can be removed.

  Next, a case where ultrasonic cleaning is performed by combining two different frequencies will be considered. If two different frequencies are used, it is possible to select both a frequency suitable for radical generation and a frequency suitable for cavitation generation, so that the residual pesticide can be more reliably removed.

Table 3 shows the experimental results of Experiment 3 for determining the removal rate of the water-soluble pesticide when ultrasonic cleaning is performed by combining two frequencies. In Experiment 3, a model test was conducted in the same manner as in Experiment 2, and tomato was used as an agricultural product and chlorothalonil was used as an intermediate water-soluble agricultural chemical. As the frequency combinations, experiments were performed for 25 kHz and 45 kHz, 25 kHz and 60 kHz, 45 kHz and 60 kHz, 25 kHz and 100 kHz, 45 kHz and 100 kHz, 60 kHz and 100 kHz, 75 kHz and 100 kHz, 45 kHz and 150 kHz, and 75 kHz and 150 kHz. In addition, ultrasonic waves with an ultrasonic intensity of 0.75 W / cm ² were irradiated for 5 minutes at each frequency.

  According to Table 3, water-soluble pesticides are removed well in almost all combinations, but the combination of two frequencies of 75 kHz or higher (75 kHz and 100 kHz, 75 kHz and 150 kHz) is compared to the other combinations. The removal rate is low. This is considered to be because the occurrence of cavitation for removing dirt is small, so when combining two frequencies, it is desirable that at least one frequency be 60 kHz or less in consideration of the occurrence of cavitation. . As shown in Table 2, sufficient cavitation can be generated at a frequency of 20 kHz or higher.

  In view of removal of poorly water-soluble agricultural chemicals, it is desirable to use ultrasonic waves in a relatively high frequency band as described above. Therefore, it is desirable to use a frequency of 40 kHz or more, and more desirably a frequency of 60 kHz or more, considering the generation of radicals as another frequency. Based on such points, an example (cleaning example 2) of a cleaning method using two frequencies by the crop cleaning apparatus according to the present embodiment will be described.

(2) Cleaning example 2
In this cleaning example 2, the first frequency ultrasonic wave selected from 20 to 60 kHz which is a frequency band considering the occurrence of cavitation and the frequency band 40 to 150 kHz which is a frequency band considering the generation of radicals are selected. The ultrasonic cleaning is performed in combination with the ultrasonic wave of the second frequency. For example, 45 kHz is selected as the first frequency and 100 kHz is selected as the second frequency.

  Specifically, under the control of the control unit 40, water containing microbubbles is supplied from the water supply port 20 into the aquarium 12, and a washing basket 30 storing the crop 50 as an object to be washed is installed in the aquarium 12. To do. When the water level of the cleaning water reaches the level of the overflow drain port 28, the overflow is drained from the overflow drain port 28.

  Then, the ultrasonic vibration unit 15 is driven at the first frequency of 45 kHz to perform ultrasonic cleaning for 5 minutes while irradiating the ultrasonic wave of 45 kHz, and then, similarly, ultrasonic cleaning with the second frequency of 100 kHz for 5 minutes. I do. In addition, water supply and overflow drainage are performed between these washing | cleaning similarly to the said washing | cleaning example 1. FIG.

  According to this cleaning example 2, a large number of cavitations are generated by the first frequency to remove easily water-soluble and moderately water-soluble residual agricultural chemicals, and a large number of radicals are generated by the second frequency to cause poor water solubility. Therefore, sufficient cleaning can be performed regardless of the type of pesticide adhering to the crop.

  In addition, when the washing water in the aquarium 12 is irradiated with ultrasonic waves, a standing wave corresponding to the frequency is generated in the water, and an abdomen and a node are formed every quarter wavelength. End up. For this reason, cleaning unevenness occurs, but if a plurality of frequencies are used as in cleaning example 2, the positions of the antinodes and nodes of the standing wave are also moved depending on the frequency, so that the cleaning unevenness can be reduced.

  Of course, also in this cleaning example 2, the first frequency and the second frequency can be appropriately changed within the respective desired ranges, and ultrasonic cleaning is performed with three or more different frequencies instead of two frequencies. Anyway. In this cleaning example 2, ultrasonic cleaning was performed at two frequencies with a time difference. However, the ultrasonic vibration unit 15 is divided into two regions that vibrate at different frequencies, and the respective regions are vibrated at different frequencies. You may comprise so that ultrasonic cleaning by two frequencies may be performed.

(3) Cleaning example 3
Next, cleaning example 3 will be described. Cleaning example 3 is basically the same as cleaning example 1 described above, but differs in that the water level in the water tank 12 is changed during ultrasonic cleaning.

  As described above, when ultrasonic waves are irradiated, standing waves according to the frequency are generated in the water, resulting in uneven cleaning. However, if the water level is changed as in this cleaning example 3, the stomach and nodes The position can be changed, and the occurrence of uneven cleaning can be suppressed.

  Specifically, under the control of the control unit 40, the water level control valve 26 is slightly opened during cleaning, and the water level in the water tank 12 is gradually lowered. At this time, since a belly and a node are formed every quarter wavelength, it is desirable to change the water level by at least a quarter wavelength. For example, when the frequency of the ultrasonic wave is 40 kHz, the wavelength is 3.8 cm, so the water level may be lowered by about 1 cm or more by removing water.

In addition, in order to change the water level in the water tank 12, water may be supplied from the water supply port 20 to raise the water level. Further, by causing the washing basket 30 to move up and down instead of changing the water level, it is possible to prevent the occurrence of washing unevenness even when the crop that is the object to be washed is moved up and down.
(4) Cleaning example 4
This cleaning example 4 is a cleaning example that combines ultrasonic cleaning with two frequencies, microbubbles, water level fluctuation, overflow rinsing, and the like. FIG. 3 is a diagram showing the relationship between the cleaning time and the water level in cleaning example 4.

  As shown in the figure, in the cleaning example 4, first, at T1, the water level is gradually lowered while performing ultrasonic cleaning for 2 minutes with 30 kHz ultrasonic waves. Specifically, the water level control valve 26 is opened and the water level in the water tank 12 is gradually lowered while the ultrasonic cleaning unit 15 is vibrated at 30 kHz under the control of the control unit 40. As the water level to be lowered, for example, if the height of the overflow drain port 28 is lowered to about half the height when the water is full, the above-described uneven cleaning due to the generation of the belly and nodes can be sufficiently prevented.

  Subsequently, at T2, cleaning water containing microbubbles is supplied from the water supply port 20 for 2 minutes. In addition, since the water supply in T2 has more water per unit time than the waste_water | drain in T1, the overflow waste_water | drain is performed from the overflow drain outlet 28 from the middle.

  At T3, while performing ultrasonic cleaning for 2 minutes with 75 kHz ultrasonic waves, the water level is gradually lowered in the same manner as at T1, and at T4, cleaning water containing microbubbles is supplied from the water supply port 20 for 2 minutes as in T2. In the second half, overflow drainage is performed.

  According to Washing Example 4 as described above, at T1, mainly water-soluble or medium-water-soluble pesticides are removed (peeled or dissolved) from the surface of the crop, and at T3, the end of the molecular structure of the poorly water-soluble pesticides. When a hydrophilic group is formed in the water, a poorly water-soluble agricultural chemical is easily dissolved in the washing water, so that it is removed (dissolved) from the crops. At T2, the pesticide that has been peeled off by the microbubbles is separated (removed), and at T4, the hardly soluble pesticide having low solubility in water is dissolved and removed by the microbubbles at the air bubble interface having hydrophobicity. Further, at T2 and T4, the pesticides removed at T1 and T3 and dissolved in the wash water are discharged out of the water tank 12 by overflow drainage, and a water flow is also generated in the water tank 12, so that the dissolved pesticides It can also be prevented that the product stays around the crop and adheres to the crop again.

  Further, in cleaning example 4, ultrasonic cleaning is performed while changing the water level, which prevents the occurrence of uneven cleaning due to the occurrence of standing waves, and also contributes to the removal of residual agricultural chemicals by the generation of microbubbles. .

  As mentioned above, although embodiment of this invention was described in detail, embodiment of this invention is not limited to the said embodiment, A various deformation | transformation is possible within the range which does not deviate from the main point of this invention. . For example, in this embodiment, the ultrasonic vibration unit 15 is installed in the lower part of the water tank 12, but may be configured to be installed in the side part of the water tank 12.

  Moreover, you may add the structure which confirms generation | occurrence | production of the radical in the water tank 12. FIG. For example, if a pigment containing an aromatic ring (such as indigo carmine or methylene blue) is placed in a container and placed in the water tank 12, the pigment containing a benzene ring is decolorized by radicals, so the color change in the container The generation of radicals in the water tank 12 can be confirmed by observing the above.

  Further, the generation of radicals, for example, whether radicals are generated at 10 ppb or more may be confirmed by measuring the hydrogen peroxide concentration in the water tank 12. In this way, if the generation of radicals is confirmed, it can be confirmed whether or not the removal of the poorly water-soluble pesticide is performed.

FIG. 1 is an image diagram schematically illustrating a configuration of a crop cleaning apparatus according to the present embodiment. FIG. 2 is a plan view of the water tank according to the present embodiment. FIG. 3 is a diagram illustrating the relationship between the time and the water level in the cleaning of the cleaning example 4 according to the present embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Farm cleaning apparatus 10 Case 12 Water tank 15 Ultrasonic vibration part 20 Water supply port 21 Micro bubble generation nozzle 22 Water supply valve 23 Inlet port 25 Drain port 26 Water level control valve 28 Overflow drain port 30 Washing basket 40 Control unit 50 Crop

Claims (5)

In the crop cleaning device for cleaning crops,
A water tank for storing the washing water in which the crops are immersed;
An ultrasonic vibration unit that is installed around the water tank and ultrasonically vibrates the cleaning water in the water tank;
Control means for controlling the ultrasonic vibration unit,
The crop cleaning apparatus according to claim 1, wherein the control means is configured to vibrate the ultrasonic vibration unit at a frequency of 40 to 150 kHz and generate radicals in the cleaning water to ultrasonically clean the crop.   The said control means combines the 1st frequency selected from 20-60kHz, and the 2nd frequency selected from 40-150kHz, and vibrates the said ultrasonic vibration part, It is characterized by the above-mentioned. A crop cleaning device. A water supply valve installed in the water supply line of the water tank;
A water level control valve installed in the drainage line of the water tank,
The control means is a control means for further controlling the water supply valve and the water level control valve, and opens the water supply valve or the water level control valve during ultrasonic cleaning, so that the level of the wash water in the water tank The crop cleaning apparatus according to claim 1 or 2, wherein ultrasonic cleaning is performed while changing the value.   The crop cleaning apparatus according to any one of claims 1 to 3, further comprising microbubble generating means installed in the water supply line of the water tank for generating microbubbles in the cleaning water. In the crop cleaning method for cleaning agricultural products and removing residual pesticides,
Immersing the crop in washing water;
Ultrasonically vibrating the washing water at a frequency of 40 to 150 kHz, generating radicals in the washing water, and ultrasonically washing the crops;
A method for cleaning an agricultural product, comprising:

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