Food product placement plate voltage application device and food product placement plate voltage application method

Abstract

To match the output impedance of an AC power supply with the load impedance.SOLUTION: An AC power supply 10 that applies an AC voltage to a conductive food product placement plate 17, and a DC power supply 11 that applies a DC voltage to the food product placement plate 17 are connected separately to the food product placement plate 17 via an AC output terminal 14 and a DC output terminal 15, respectively. The AC voltage and DC voltage are simultaneously applied to the food product placement plate 17. The output impedance 30 of the AC power supply 10 is matched with the load impedance in a state where a food product is placed on the food product placement plate 17, and the AC voltage is applied to the food product placement plate 17.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a food placement plate voltage application device and a food placement plate voltage application method for applying both a DC potential and an AC potential to food for preserving the food. [Background technology]

[0002] One method for long-term storage of food involves placing a conductive food placement plate inside a refrigerator and placing food on the food placement plate, and then cooling and storing the food while simultaneously applying AC and DC voltages to the food placement plate (Patent Document 1). In Patent Document 1, the period during which AC voltage and DC voltage are applied simultaneously is defined as the DC / AC simultaneous application period, and after the DC / AC simultaneous application period has elapsed, the food is cooled and stored in a state in which only DC voltage or AC voltage is applied to the food placement plate. The food may be, for example, a gel food such as agar jelly solidified with agar, fresh food such as meat, seafood, vegetables, and fruits, or general edible foods such as sweets, frozen desserts, bread, side dishes, pickles, beverages, alcoholic beverages, and food additives. In addition, raw foods such as raw young fish and raw minced meat (fish meat minced meat, livestock meat minced meat), which have been difficult to freeze without the use of additives due to severe freezing damage in the past and have been significantly degraded in quality after thawing even if frozen, may also be used. Refrigerated storage and frozen storage methods are widely used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4932255 [Patent Document 2] Patent No. 5504543 [Patent Document 3] Patent No. 6366882 Summary of the Invention [Problem to be solved by the invention]

[0004] Using a device configured as in the embodiment of Patent Document 1, the applied voltage was set when the food loading plate was empty, and the amount of food placed on the food loading plate was changed without changing the set voltage. The actual voltage measured on the food loading plate is shown in Figure 1. Specifically, the actual voltage is the voltage actually applied when the set values ​​were AC=2000v and DC=0v. 2 and 3, the reason why the voltage value applied to food placement plate 17 fluctuates will be described. 2 shows shelf 12, on which multiple food placement plates 17 are placed, placed inside freezer 13. Shelf 12 is insulated from freezer 13, and the outputs of AC power supply 10 and DC power supply 11 are connected to shelf 12 via AC voltage application cable 14 and DC voltage application cable 15, respectively. Shelf 12 is made of a conductive material, and all food placement plates 17 are also made of a conductive material, so that the voltage applied to shelf 12 is also applied to all food placement plates 17. Freezer 13 is grounded 16. Fig. 3 is a diagram explaining why the voltage fluctuates. The output of AC voltage source 25 from AC power supply 10 is applied to shelf 12 through output impedance 30, and the space between shelf 12 and freezer 13 can be regarded as an equivalent capacitor 24. Capacitor 27 from DC power supply 11 can be ignored because ideally it has infinite impedance. When food is placed on shelf 12, food generally has a larger dielectric constant than air, so as the amount of food increases, the capacitance increases and the impedance of equivalent capacitor 24, which is expressed equivalently, decreases. The reason for this is that capacitance is generally expressed as in Equation 1, and as the dielectric constant ε increases, the capacitance C increases. C=ε×S / d (Formula 1) Here, C is the capacitance, ε is the dielectric constant, S is the area of ​​the electrodes, and d is the distance between the electrodes. The impedance Z of the equivalent capacitor 24 is given by the following equation 2. Z=1 / (ω×C) (Equation 2) Here, ω=2πF, F is the power supply frequency. When the impedance of the equivalent capacitor 24 decreases, the current supplied to the equivalent capacitor 24 increases, causing a larger voltage drop due to the output impedance 30 of the power supply, and therefore a smaller voltage is applied to the equivalent capacitor 24. In this case, the set voltage is not applied to the food, and the expected charge is not applied to the food. Moreover, Patent Document 2 proposes a method for preventing the applied voltage from being reduced when the volume of the object to be frozen changes. Patent Document 2 describes a method in which one side of the secondary output is connected to an application shelf and the other side is connected to the core of a step-up transformer. The core is grounded via an insulating member. According to Patent Document 2, even if the capacitance of the object increases, the attenuation of the applied voltage becomes small. However, even with the method of Patent Document 2, it is not possible to apply the same voltage when the capacitance of the object changes. In addition, in Patent Document 3, one of the secondary outputs is wired back to the primary feedback control circuit to control the secondary output. However, even if only the voltage is controlled, if the impedance of the output side and the impedance of the input to which the voltage is applied do not match, energy loss occurs, and there is a problem that the charge is not applied to the target object. [Means for solving the problem]

[0005] The voltage application method for a food placement plate of the present invention as described in claim 1 is a voltage application method for a food placement plate in which an AC power supply which applies an AC voltage to a conductive food placement plate, and a DC power supply which applies a DC voltage to the food placement plate are separately connected to the food placement plate via an AC output terminal and a DC output terminal, respectively, and the AC voltage and the DC voltage are applied simultaneously to the food placement plate, characterized in that the AC voltage is applied to the food placement plate by matching the load impedance when food is placed on the food placement plate with the output impedance of the AC power supply. The present invention as set forth in claim 2 provides the food placement plate voltage application method as set forth in claim 1, further comprising an impedance changing unit that changes the load impedance, and a current detection unit that detects a current value between the AC power source and the food placement plate, The impedance change unit changes the impedance so that the current value detected by the current detection unit becomes a maximum value. The present invention as set forth in claim 3 is characterized in that, in the food placement plate voltage application method as set forth in claim 1, an inverter unit that changes the frequency of the AC power source is further provided. In the food placement plate voltage application device of the present invention as described in claim 4, an AC power supply which applies an AC voltage to a conductive food placement plate, and a DC power supply which applies a DC voltage to the food placement plate are separately connected to the food placement plate via an AC output terminal and a DC output terminal, respectively, and the food placement plate voltage application device applies the AC voltage and the DC voltage to the food placement plate simultaneously, and is characterized in that it includes a control unit which applies the AC voltage to the food placement plate by matching the load impedance when food is placed on the food placement plate with the output impedance of the AC power supply. The present invention as described in claim 5 is characterized in that, in the food placement plate voltage application device as described in claim 4, it further comprises an impedance changing unit that changes the load impedance and a current detection unit that detects the current value between the AC power source and the food placement plate, and the control unit changes the impedance changing unit so that the detected current value of the current detection unit becomes a maximum value. The present invention as set forth in claim 6 is characterized in that, in the food placement plate voltage application device as set forth in claim 4, an inverter unit is provided that changes the frequency of the AC power supply. Effect of the Invention

[0006] In the present invention, the output impedance of the AC power source is matched to the load impedance, so that a set voltage can be applied to the shelf. That is, 1 / 2 of the output voltage of the AC power source is applied. Conversely, if the impedance is not matched, 100% of the input energy is not applied, and energy reflection occurs, and the input energy applied and the energy applied to the food may not match. In other words, even if the voltage and time are controlled and applied, the corresponding charge may not be applied, and the expected effect may not be sufficient. By properly matching, almost 100% of the input energy is applied, and the voltage, time, and other settings are applied, so that the correlation between the effect on the food and the applied charge can be correctly understood. Furthermore, if the impedance matching is performed by the control unit, the time required to learn the technique for impedance matching and the time required to perform impedance matching can be saved, allowing the operator to concentrate on the original mission of improving freezing quality. Above all, the application device can always be used with impedance matching, so the correct voltage as set is applied to the food. As a secondary effect, when impedance matching is not achieved, unnecessary radiation noise can be generated, which can cause nearby medical equipment to malfunction or noise can be prevented from entering receiving devices such as radios and televisions. Furthermore, when adding a charge application device to an existing freezer, refrigerator, storage, etc., or when installing an existing charge application device in a freezer, refrigerator, storage, etc., there is no restriction on the combination of the application device and a food storage such as a freezer, and the application device can be added to any storage. In addition, it is possible to add all application devices to any storage, and there is no need to remodel the application device or storage. Therefore, the present invention is effective economically and also from the perspective of the SDGs. [Brief description of the drawings]

[0007] [Figure 1]A diagram showing voltage measurement results when using a conventional food preservation device. [Diagram 2] FIG. 1 shows a shelf 12 on which multiple food placement trays 17 are mounted, inserted into a freezer 13. [Diagram 3] Diagram explaining why voltage fluctuates [Figure 4] FIG. 1 is a schematic diagram showing an output circuit of an AC power source 10 of a food placement plate voltage application device of the present invention. [Diagram 5] FIG. 3 is an equivalent diagram of the main part of FIG. 2. [Figure 6] FIG. 1 is an equivalent circuit diagram showing a food placement plate voltage application device according to an embodiment of the present invention; [Figure 7] FIG. 11 is an equivalent circuit diagram showing a food placement plate voltage application device according to another embodiment of the present invention; [Figure 8] FIG. 11 is an equivalent circuit diagram showing a food placement plate voltage application device according to still another embodiment of the present invention; EXAMPLES

[0008] 4 is a diagram showing a schematic diagram of an output circuit of AC application power supply 10 of the present invention. The output section of AC application power supply 10 is the output of neon transformer 21. Neon transformer 21 has neon transformer core 32 between primary coil 22 and secondary coil 23, and serves as a magnetic leakage transformer. Therefore, of the two outputs of secondary coil 23, the output that is not AC application cable 14 is grounded 16. Secondary coil 23 forms output impedance 30 (see FIG. 5).

[0009] Fig. 5 is an equivalent diagram of the main parts of Fig. 2. The output of AC voltage source 25 is applied to shelf 12 through output impedance 30, which can be regarded as an equivalent capacitor 24 formed between shelf 12 and freezer 13. The output of DC voltage source 26 is capacitor 27. DC voltage source 26 can be ignored because ideally its impedance is infinite.

[0010] 6 is an equivalent circuit diagram showing a food placement plate voltage application device according to one embodiment of the present invention. An impedance change unit 28 and a current detection unit 29 are connected in series between the AC application power source 10 and the shelf 12. In this embodiment, a variable resistor is used as the impedance change unit 28. If the impedance by the impedance changing unit 28 is X, the condition for matching the impedance X is expressed as Equation 3. The impedance change unit 28 is composed of a coil and a capacitor.

[0011] ΩL=((1 / ωC2)×((1 / ωC1)+X)) / ((1 / ωC2)+((1 / ωC1)+X))=(1+ω×C1) / (ωC1+ωC2+ω 2 ×C1C2) (Formula 3)

[0012] Here, L is the reactance of the secondary coil 23, C1 is the conductance of the equivalent capacitor 24, C2 is the conductance of the capacitor 27, and ω is the frequency of the AC power supply. In general, 1>>ω×C1, ω 2 ×C1C2>>ωC1, ω 2 ×C1C2>>ωC2, we get equation 4.

[0013] X=1 / KC1C2(K: constant) (Formula 4)

[0014] When C1 changes and the capacitance increases, impedance X decreases. Conversely, when C1 changes and the capacitance decreases, impedance X increases. Therefore, matching can be achieved by adjusting the value of impedance X to increase or decrease it in accordance with changes in the content volume. When using a resistor as impedance X, the resistance value can be increased or decreased by using a variable resistor, and impedance X can be matched by changing the resistance value.

[0015] Matching of impedance X can be performed by manually controlling impedance modification unit 28 while watching current detection unit 29, but it is preferable to perform it by control unit 50. The output of current detection unit 29 is converted into analog and digital form, and read by software via the IO of the personal computer. For example, a motor is rotated by the software via the IO of the personal computer so that the detected current value becomes maximum, and the shaft of impedance modification unit 28 is linked to the rotating shaft. In this way, the detected current value can be adjusted to the maximum value by control unit 50. Since matching is achieved when the detected current value by current detection unit 29 becomes maximum, impedance modification unit 28 is changed so that the detected current value becomes maximum.

[0016] For example, if the impedance change unit 28 changes the impedance X in a direction to decrease it and the detected current value increases, the change in the direction to decrease the impedance X is continued. If the change in the direction to decrease the impedance X is further continued, the detected current value will start to decrease, and it can be determined that the detected current value will reach its maximum value at the timing before the detected current value starts to decrease. Furthermore, if the impedance change unit 28 changes the impedance X in a direction to decrease it and the detected current value decreases, the impedance change unit 28 changes the impedance X in a direction to increase it. By changing the impedance X in a direction to increase it, the detected current value increases. If the change in the direction to increase the impedance X is further continued, the detected current value will start to decrease, and it can be determined that the detected current value will reach its maximum value at the timing before the detected current value starts to decrease.

[0017] In this way, control unit 50 changes impedance modification unit 28 so that the current value detected by current detection unit 29 becomes the maximum value. By changing impedance modification unit 28 so that the current value detected by current detection unit 29 becomes the maximum value, it is possible to apply an AC voltage to food placement plate 17 by matching the load impedance with food placed on food placement plate 17 with the output impedance 30 of the AC power source.

[0018] FIG. 7 is an equivalent circuit diagram showing a food placement plate voltage application device according to another embodiment of the present invention. In this embodiment, an inverter capable of changing the power supply frequency is used as the impedance changing unit 28. An inverter capable of changing the power supply frequency is provided at the input of the neon transformer 21 shown in FIG. Matching of impedance X can be performed by manually controlling impedance modification unit 28 while watching current detection unit 29, but it is preferable to perform it by control unit 50. The output of current detection unit 29 is converted into analog and digital form, and read by software via the IO of the personal computer. For example, a motor is rotated by the software via the IO of the personal computer so that the detected current value becomes maximum, and the shaft of impedance modification unit 28 is linked to the rotating shaft. In this way, the detected current value can be adjusted to the maximum value by control unit 50. Since matching is achieved when the detected current value by current detection unit 29 becomes maximum, impedance modification unit 28 is changed so that the detected current value becomes maximum.

[0019] In this embodiment as well, control unit 50 changes impedance modification unit 28 so that the current value detected by current detection unit 29 becomes the maximum value. By changing impedance modification unit 28 so that the current value detected by current detection unit 29 becomes the maximum value, it is possible to apply an AC voltage to food placement plate 17 by matching the load impedance when food is placed on food placement plate 17 with the output impedance 30 of the AC power source.

[0020] FIG. 8 is an equivalent circuit diagram showing a food placement plate voltage application device according to still another embodiment of the present invention. In this embodiment, a plurality of impedance change units 28 are provided. FIG. 8 shows impedance changing section 28a using a variable resistor and impedance changing section 28b using an inverter capable of changing the power supply frequency. In this embodiment, control unit 50 sets a predetermined frequency by impedance modification unit 28b, and modifies impedance modification unit 28a so that the current value detected by current detection unit 29 becomes the maximum value. By modifying impedance modification unit 28a so that the current value detected by current detection unit 29 becomes the maximum value, it is possible to apply an AC voltage to food placement plate 17 by matching load impedance 30 with food placed on food placement plate 17 with the output impedance of the AC power source. [Industrial Applicability]

[0021] According to the present invention, an AC voltage suitable for food can be applied to the food placement plate. [Explanation of symbols]

[0022] 10 AC applied power supply (AC power supply) 11 DC applied power supply (DC power supply) 12 Shelves 13 Freezer 14 AC voltage application cable (AC output terminal) 15 DC voltage application cable (DC output terminal) 16 Grounding 17 Food placement plate 21 Neon Trance 22 Primary coil 23 Secondary coil 24 Equivalent Capacitor 25 AC voltage source 26 DC Voltage Source 27 Condenser 28, 28a, 28b Impedance change unit 29 Current detection section 30 Output impedance 32 Neon transformer core 50 Control section

Claims

1. An AC power source that applies an AC voltage to a conductive food placement plate and a DC power source that applies a DC voltage to the food placement plate are connected to the food placement plate separately via AC output terminals and DC output terminals, respectively; A food placement plate voltage application method for simultaneously applying the AC voltage and the DC voltage to the food placement plate, characterized in that the AC voltage is applied to the food placement plate by matching the load impedance when food is placed on the food placement plate with the output impedance of the AC power source.

2. an impedance changing unit that changes the load impedance; and a current detecting unit that detects a current value between the AC power source and the food placement plate, The impedance change unit is changed so that the current value detected by the current detection unit becomes a maximum value.

2. The method of claim 1, wherein the voltage is applied to a food placement plate.

3. An inverter unit that changes the frequency of the AC power supply is provided.

2. The method of claim 1, wherein the voltage is applied to a food placement plate.

4. An AC power source that applies an AC voltage to a conductive food placement plate and a DC power source that applies a DC voltage to the food placement plate are connected to the food placement plate separately via AC output terminals and DC output terminals, respectively; A food placement plate voltage application device that applies the AC voltage and the DC voltage simultaneously to the food placement plate, and includes a control unit that applies the AC voltage to the food placement plate by matching a load impedance when food is placed on the food placement plate with an output impedance of the AC power source. A food placement plate voltage application device.

5. an impedance changing unit that changes the load impedance; and a current detecting unit that detects a current value between the AC power source and the food placement plate, The control unit changes the impedance change unit so that the current value detected by the current detection unit becomes a maximum value.

5. The food placement plate voltage application device according to claim 4.

6. An inverter unit that changes the frequency of the AC power supply is provided.

5. The food placement plate voltage application device according to claim 4.

Images