JP2001017136A - Sterilizing device for liquid state material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sterilizing device capable of repeating an electric field sterilization treatment on a liquid state material in plural times while mediating a cooling treatment, and also aiming at the simplification and miniaturization of the device as a whole. SOLUTION: This sterilizing device has a sterilization treating part 30 having a structure of nipping one piece of a high voltage electrode 14 between 2 pieces of ground electrodes 12. Between each of the ground electrodes 12 and the high voltage electrode 14, a liquid state material 2 is flown and electric field treating parts 15a, 15b for performing the electric field treatment by impressing a pulse electric field Ep on the liquid state material 2, are formed. Between the high voltage electrode 14 and each of the ground electrodes 12, the pulse electric voltage Vp is impressed from a pulse electric source 18. The untreated liquid state material 2 supplied to one of the electric field-treating part 15a, is treated in there, and then cooled by a cooling system 24, returned to the other electric field treating part 15b and received the electric field sterilization treatment again. Thereby, it becomes possible to perform the electric field sterilization treatment for 2 times by mediating with the cooling treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to sterilization by applying a pulsed electric field of a high electric field to liquid substances (including liquids) such as liquid foods such as juice, cosmetics, and culture solution for hydroponics. More specifically, the present invention relates to an improvement of a sterilization apparatus of a type in which electric field sterilization processing and cooling processing are alternately performed on a liquid material.

[0002]

2. Description of the Related Art As one of sterilization methods for a liquid material, an electric field sterilization method using a pulse electric field is known. See, for example, Japanese Patent No. 2781558. In brief, this electric field sterilization method involves applying a pulsed electric field (specifically, a pulsed high electric field) to a liquid material.
Is applied a certain number of times to destroy and sterilize the cell membrane of bacteria in the liquid.

[0003] Since the electric field sterilization method can sterilize at a relatively low temperature, the quality of liquids (for example, the decrease in the flavor and nutritional value of foods) is less than that of the heat sterilization method. Energy is not required, so that energy can be saved.

FIG. 4 shows one conventional example of a sterilizer using the electric field sterilization method.

[0005] This sterilization apparatus supplies an untreated tank 4 for storing untreated (before sterilization treatment) liquid material 2, a pump 6 for sending out the liquid material 2 from the untreated tank 4, and a sterilization treatment section 10. a preheater 8 for heating the liquid product 2 preliminarily sterilizing unit 1 for sterilizing the liquid substance 2 by the pulse electric field E _P
0, and a pulse power source 18 for applying repeatedly a pulse voltage V _P to the sterilization unit 10, and a processed tank 20 to accumulate the liquid material 2 of treated leaving the sterilization unit 10.

[0006] The sterilizing section 10 has two flat ground electrodes 12 and high voltage electrodes 14 arranged alongside each other, and the liquid 2 flows between the electrodes 12 and 14.
Reference numeral 16 denotes an insulator.

[0007] between the electrodes 12 and 14 of the sterilization unit 10, and for example, the pulse width from the pulse power source 18 applies a pulse voltage V _P of not less than about 500 ns, the electrodes 12 and 14
For example, 15 kV / cm to 70 kV / cm
A pulsed electric field E _P of the degree of field strength, by the liquid substance 2 is applied, for example, about several shots to several tens shots while passing through the sterilization unit 10 may be subjected to sterilization treatment in the liquid product 2.

[0008] It is known that the sterilizing effect of the electric field sterilization method depends on the temperature of the liquid material 2 during the sterilizing treatment (that is, the higher the temperature, the higher the sterilizing effect). Varying the temperature of the liquid substance 2 is raised by Joule heating by application of the pulse electric field E _P in the sterilization unit 10, the temperature of the liquid product 2 unprocessed, electric field sterilization process temperature range (e.g., less than 40 ° C. less effective In the case of (1), the preheater 8 is often provided as in this example, and the liquid material 2 is preliminarily heated to a lower temperature (for example, about 40 ° C.) than in the case of the conventional heat treatment method.

By the way, from the viewpoint of preventing quality deterioration of the liquid material 2 (for example, deterioration of food flavor and nutritional value), it is desirable that the temperature of the liquid material 2 after the sterilization treatment is low. But,
As described above, the temperature of the liquid material 2 is also increased by the application of the pulsed electric field. Therefore, in the sterilization apparatus, in order to obtain a desired sterilization effect in the sterilization processing unit 10, the temperature of the liquid material 2 after the sterilization process increases. If the temperature of the liquid material 2 after the sterilization is too low, a desired sterilization effect may not be obtained.

In order to solve this problem, it is necessary to repeatedly cool the liquid material 2 after the sterilization treatment and perform the sterilization treatment again as proposed in, for example, US Pat. No. 5,514,391. Is valid. FIG. 5 shows a main part of a conventional example of a sterilization apparatus using such a method.

In this sterilizing apparatus, a plurality of sterilizing sections 10 as described above and coolers 22 for cooling the liquid 2 discharged from each sterilizing section 10 are alternately arranged. Each sterilization unit 10, the pulse voltage V _P as described above from the pulse power source 18 is applied.

According to such a sterilizer, the electric field sterilization process can be repeated a plurality of times while interposing a cooling process on the liquid material 2, so that the temperature rise of the liquid material 2 can be suppressed. At the same time, even if the temperature of the liquid material 2 is low, the effect of sterilization treatment is repeated a plurality of times, so that an effective sterilization effect can be obtained. Therefore, such a sterilizing apparatus is particularly effective for the liquid material 2 which particularly needs to reduce the temperature after the sterilizing treatment.

[0013]

However, in the sterilization apparatus shown in FIG. 5, a plurality of sterilization sections 10 are required for performing the electric field sterilization a plurality of times. There is a problem of increasing the size.

Therefore, the present invention provides a sterilizing apparatus capable of performing electric field sterilization processing on a liquid material a plurality of times while intervening cooling processing, and further achieving simplification and downsizing of the entire apparatus. Its primary purpose is to provide.

[0015]

According to the present invention, there is provided a sterilization apparatus comprising:
A total of three or more grounded ground electrodes and ungrounded high-voltage electrodes are alternately arranged, and a liquid material is flown between adjacent ground electrodes and high-voltage electrodes and subjected to electric field sterilization. A sterilization processing unit in which a processing unit is formed,
A pulse power supply for applying a pulse voltage between each high-voltage electrode and each ground electrode of the sterilizing section, and another liquid after cooling a liquid substance from one electric field processing section of the sterilizing section through a cooler, And one or more cooling systems for returning to the electric field processing unit.

According to this sterilizing apparatus, the liquid material subjected to the electric field sterilization in one electric field processing section of the sterilization processing section is cooled through the cooling system, and then returned to another electric field processing section of the sterilization processing section. , Where it is again subjected to electric field sterilization. Therefore,
The electric field sterilization process can be repeatedly performed on the liquid material a plurality of times while intervening the cooling process.

Further, according to this sterilizing apparatus, only one sterilizing section is required. In the sterilizing section, one electrode is shared by the two electric field processing sections by alternately arranging the ground electrode and the high voltage electrode, so that the configuration can be simplified. As a result, the entire device can be simplified and downsized.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a main part of an example of a sterilizer according to the present invention. The same or corresponding parts as those of the conventional example shown in FIG. 4 and FIG.
Hereinafter, differences from the conventional example will be mainly described.

This sterilizing apparatus includes a sterilizing section 30 having the following configuration, one cooling system 24, and the above-described pulse power supply 18.

The sterilization section 30 has a structure in which one non-grounded high voltage electrode 14 is sandwiched between two grounded electrodes 12 which are both flat and grounded. That is, it has a three-layer plate structure. Between the respective ground electrodes 12 are adjacently high-voltage electrode 14, liquid material 2 is flowed by applying a pulsed electric field E _P as described above to the liquid material 2 subjected to the field-sterilized field processor 15a And 15b are formed respectively (that is, two in this example). Reference numeral 16 denotes an insulator. The untreated liquid material 2 is supplied to one electric field processing unit 15a of the sterilization processing unit 30, and the processed liquid material 2 is taken out from the other electric field processing unit 15b.

The above-described pulse voltage _VP is applied from the pulse power supply 18 between the high-voltage electrode 14 of the sterilizing section 30 and each of the ground electrodes 12.

The cooling system 24 has a cooler 26 for cooling the liquid material 2. After cooling the liquid material 2 discharged from the one electric field processing unit 15 a of the sterilization processing unit 30 through the cooler 26, , To the other electric field processing unit 15b. The cooler 26 is a heat exchanger in this example, and cools the liquid material 2 by cooling water 28 supplied thereto.

According to this sterilization apparatus, the liquid material 2 which has been subjected to the electric field sterilization in one electric field processing unit 15a of the sterilization processing unit 30 is cooled by the cooler 26 through the cooling system 24, and then is cooled. It is returned to the other 30 electric field processing units 15b, where it undergoes electric field sterilization processing again. Therefore, the liquid material 2 is subjected to electric field sterilization treatment by intervening cooling treatment.
It can be repeated several times. That is, two electric field sterilization processes and one cooling process can be performed alternately. As a result, the sterilization effect on the liquid material 2 can be enhanced while suppressing the temperature rise of the liquid material 2.

Further, according to this sterilizing apparatus, only one sterilizing section 30 is required. In the sterilizing section 30, the high voltage electrode 14 is interposed between the two ground electrodes 12, so that one high voltage electrode 14 is shared by the two electric field processing sections 15a and 15b. Can be As a result, the entire device can be simplified and downsized.

Further, in this sterilizer, the ground electrodes 12 are arranged on both outer sides, and the high-voltage electrodes 14 are arranged inside.
In other words, the ground electrodes 12 are arranged at odd-numbered (first and third) positions from the outside, and the high-voltage electrodes 14 are arranged at even-numbered (second) positions from the outside. Safety is enhanced. In addition, since only one high-voltage power supply unit from the pulse power supply 18 is required, power supply is simplified.

The sterilizing apparatus shown in FIG.
0 is a five-layer plate structure. This will be described mainly with respect to differences from the example of FIG.

The sterilizing section 30 includes three ground electrodes 1
It has a structure in which two and two high voltage electrodes 14 are alternately arranged. The above-described electric field processing units 15a to 15d are formed between adjacent ground electrodes 12 and adjacent high voltage electrodes 14, respectively (that is, four in this example). In this example, the untreated liquid material 2 is supplied to the one end side electric field processing unit 15a, and the processed liquid material 2 is taken out from the other end electric field processing unit 15d. However, other uses may be used.

The sterilizing apparatus further comprises a cooling system 24a for cooling the liquid material 2 discharged from one electric field processing section 15a of the sterilizing section 30 through the cooler 26 and returning it to the other electric field processing section 15b. A cooling system 24b for cooling the liquid material 2 discharged from the portion 15b through the cooler 26 and returning the liquid material 2 to another electric field processing unit 15c, and cooling the liquid material 2 discharged from the electric field processing unit 15c A cooling system 24c for returning to the electric field processing unit 15d. Each cooler 26 is the same as in the example of FIG.

According to this sterilizing apparatus, the liquid material 2 is subjected to electric field sterilization treatment by cooling treatment respectively.
It can be repeated several times. That is, the electric field sterilization process four times and the cooling process three times can be performed alternately. Therefore, the disinfection effect on the liquid material 2 can be increased more than the disinfection device of FIG.

Further, in the case of this sterilizing apparatus, similarly to the example shown in FIG.
2, and the high-voltage electrodes 14 are arranged at even-numbered (second and fourth) positions from the outside, so that both outsides serve as the grounding electrodes 12, thereby improving electrical safety. Further, since only two high-voltage power supply units from the pulse power supply 18 are required, power supply is simplified.

The untreated liquid 2 to the sterilizing section 30 is supplied from the untreated tank 4 by the pump 6 in the same manner as in the case of the conventional example in FIG. 4, for example. As described above, the liquid material 2 may be supplied after being preheated by the preheater 8.

The treated liquid 2 from the sterilizing section 30 is supplied to the treated tank 2 in the same manner as in the prior art shown in FIG.
Although introduced to 0, the liquid 2 may be cooled during the introduction.

The intervals d (see FIG. 1) between the electric field processing units 15 (15a and 15b in the example of FIG. 1, 15a to 15d in the example of FIG. 2) of the sterilization processing unit 30. In this case, the distance between the two electrodes 12 and 14) and the plane area may be equal to each other in the electric field processing units 15 or may be different from each other. For example, when a plurality of types of bacteria are present in the liquid material 2 to be treated, and the electric field strengths optimal for sterilizing each of the bacteria are different,
By changing the interval between the sterilizing sections 15, it is possible to perform sterilizing processing with a different electric field strength in each sterilizing section 15, more specifically, an electric field strength according to the type of bacteria. Sterilization treatment becomes possible.

In the example of FIGS. 1 and 2, the cooler 2
Although the cooling water 28 is used as a cooling medium for the liquid material 2 in Step 6, the cooler 26 has not been treated (therefore, before the temperature rise due to the application of the electric field), as in the example shown in FIG.
The liquid 2 may be supplied and used instead of the cooling water. By doing so, the liquid 2 from the sterilizing section 30 can be cooled by the untreated liquid 2, and the unheated liquid preheated from the cooler 26 by the heat exchange accompanying this cooling. Since the product 2 is obtained, it can be supplied to the sterilization processing unit 30 as illustrated. By doing so, one cooler (heat exchanger) 26
Serves both as a cooler and a pre-heater, so that there is no need to provide a dedicated pre-heater.

The cooling system 24 as shown in FIG. 3 may be employed in at least one of the cooling systems 24a to 24c of the sterilizing apparatus shown in FIG. In addition, there is obtained an effect that it is not necessary to provide a dedicated pre-heater.

Even when a coolant other than the liquid 2 such as the cooling water 28 is used for each of the coolers 26, the coolant is used as a circulation system, and the cooling (heat exchange) of the coolant is performed as described above. Untreated liquid material 2 may be used. Even in such a case, it is possible to obtain the effect that the dedicated pre-heater need not be provided as described above.

In any of the above examples, the sterilizing section 30 may perform the sterilizing process while the liquid material 2 is pressurized to a pressure of, for example, about several kg / cm ² . By doing so, since bubbles are less likely to be generated in the liquid material 2 during the sterilization process, abnormal electric breakdown due to the bubbles can be prevented, and the electric field sterilization process can be stably performed.

[0038]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, the liquid material can be subjected to the electric field sterilization treatment a plurality of times while interposing a cooling process. The bactericidal effect can be enhanced.

Further, according to the present invention, only one sterilizing section is required. In the sterilizing section, one electrode is shared by the two electric field processing sections by alternately arranging the ground electrode and the high voltage electrode, so that the configuration can be simplified. As a result, the entire device can be simplified and downsized.

According to the second aspect of the present invention, since both outer sides of the sterilizing section serve as ground electrodes, electrical safety is improved. Further, since the number of high-voltage power supply units from the pulse power supply can be reduced, power supply is also simplified.

According to the third aspect of the present invention, since one heat exchanger serves both as a cooler and a pre-heater for the liquid material, it is not necessary to provide a dedicated pre-heater.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of an example of a sterilization apparatus according to the present invention.

FIG. 2 is a diagram showing a main part of another example of the sterilization apparatus according to the present invention.

FIG. 3 is a diagram showing a main part of still another example of the sterilization apparatus according to the present invention.

FIG. 4 is a diagram showing an example of a conventional sterilization apparatus.

FIG. 5 is a view showing a main part of another example of the conventional sterilization apparatus.

[Explanation of symbols]

 2 Liquid 12 Ground electrode 14 High voltage electrode 15 Electric field processing unit 18 Pulse power supply 24 Cooling system 26 Cooler 30 Sterilization processing unit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeru Kato 47-47 Umezu Takaune-cho, Ukyo-ku, Kyoto-shi, Kyoto Prefecture (72) Inventor Yu Kawakita 47-47 Umezu-Takaunecho, Ukyo-ku, Kyoto-shi, Kyoto Nissin Electric In-house F term (reference) 4B021 LA42 LP01 LP10 LT03 LW06 4C058 AA21 AA22 AA30 BB02 CC04 CC05 DD04 EE26 4D061 DA10 DB01 EA13 EB01 EB07 EB14 EB17 EB20 FA20

Claims (3)

[Claims] A grounded ground electrode and a non-grounded high-voltage electrode are alternately arranged in total of three or more. A liquid material flows between adjacent ground electrodes and high-voltage electrodes, and an electric field is applied to the liquid. A sterilization section in which an electric field processing section for performing sterilization processing is formed; a pulse power supply for applying a pulse voltage between each high-voltage electrode and each ground electrode of the sterilization section; A liquid material sterilizing apparatus, comprising: one or more cooling systems for cooling a liquid substance discharged from one electric field processing unit through a cooler and returning the liquid substance to another electric field processing unit. 2. The sterilizing section has a total of three or more odd-numbered electrodes, wherein ground electrodes are arranged odd-numbered from the outside, and high-voltage electrodes are arranged even-numbered from the outside. A sterilizer for liquids according to claim 1. 3. The cooling device in at least one of the cooling systems of the cooling system is a heat exchanger that cools a liquid discharged from the electric field processing unit using an untreated liquid. Or a sterilizer for liquids according to 2.