KR20000013474A - High electric fields sterilizing device and chamber for sterilization - Google Patents

Abstract

PURPOSE: A high voltage high current pulsed electric fields sterilizing device and a chamber for sterilization are provided to be able to be manufactured easily while having uniform electric fields and to make it possible the adjusting of the intervals of the electrodes by inserting many insulating rings to two electrodes of the sterilizing chamber. CONSTITUTION: The sterilizing device is composed of: a high voltage power supply device(1) to boost the voltage of the input D.C. power supply according to the alternate switch control signals(Q1-Q4); a driving pulse generator(2) to output the driving pulse according to the input control signal; a low band filter(3) to filter the high voltage noise generated in switching; a transformer(4) to heat the cathode(K) of a thyratron(S1); a first and a second high voltage divider(HVD1,2)(5,7) to divide the supplied high voltage; and a sterilizing chamber(6) to sterilize by forming an electric field according to the fed high voltage.; Herein, the sterilization efficiency is improved according to the uniform electric field, the easiness of manufacturing, the low energy consumption.

Description

High system sterilizer and sterilization chamber

The present invention relates to a high-temperature sterilization apparatus and a sterilization chamber, and more particularly, to a low-temperature sterilization method using high voltage high current pulsed electric fields (HVHC-PEF or less 'high electric field'). A sterilization chamber comprising: a high pressure pulse power supply for disinfecting a double layer of living bacteria or microorganisms in a fluid food by applying a high electric field to the fluid food, and a plurality of insulator rings inserted between the electrodes to control electrode spacing; The present invention relates to a sterilization chamber that is easy to manufacture so that a uniform electric field is applied to the fluid food.

Most food preservation methods used in the food industry today use preservation methods by chemical operations such as heating a food or adding a food preservative. However, in the heating operation, loss of quality, such as destruction of nutritional components, changes in food structure, and loss of fragrance components due to heat, is inevitable, and the use of artificial preservatives used as the food preservatives is also refrained.

Recent interest in health has increased the demand for Minimal Processing Foods that maintain the quality of the natural state as much as possible. The minimum processing refers to a processing method capable of maintaining the original fresh quality of the food as possible and giving a safe shelf life. For example, in the conventional method of sterilizing milk, most of the pasteurization is performed at about 72 ° C. for 30 minutes or at about 135 ° C. for 2 to 3 seconds. The existing pasteurization method used in this way is used to minimize the destruction of vitamins or nutrients contained in food, and the high temperature sterilization method is used when stored for a long time, but has a conflicting nature.

Therefore, innovation in food processing and packaging technology is required, and various nonthermal operation processing technologies are being developed accordingly.

Among the non-heating processing technology, in particular, the high-voltage large current pulse type electric field processing technology is a processing technology by electrical and physical operation, unlike the conventional thermal and chemical methods, and is evaluated as a high technology that will bring a great change to the food industry. In the future, if this non-heating processing technology is put into practical use, it will be able to provide consumers with high quality, safe foods that are much better in quality, contain natural nutrients, and are fresh and have excellent taste. As shown in FIG. 1, in the sterilization method using a high electric field, a high voltage power is applied to a sterilization chamber for a predetermined time to form a high electric field E at both ends of an electrode, wherein the high electric field is a fluid food. The product will explode the double layer of living organisms such as bacteria and microorganisms.

The HVHC-PEF method introduced to date has introduced a power supply device using a spark gap or a power supply device using a pulse compression circuit, which has many disadvantages in the construction of the device. In the present invention, a high-voltage pulse field generator using a cytrontron switch having an exponential output of a simple configuration and a square wave pulse generator using a new pulse forming circuit of a modified type are shown.

Meanwhile, the bubble bubbles generated during the sterilization treatment are caused by a design error such as a structure inside the sterilization chamber, a cooling and power supply device, and a precision measurement of a high electric field, and the bubble bubbles are broken due to sparking. As it affects the noise and deterioration of sterilization efficiency, there is a problem that ultimately causes breakage of the addressee. In addition, in consideration of the practicality of the device, it is also essential that the production is easier and have a uniform electric field. Therefore, bubble problems that cause problems in sterilization treatment and the fact that they should be easy to manufacture and lighting that should have a uniform internal electric field should be considered in the design of the sterilization chamber. Provides an excellent chamber of another structure.

To date, the food processing technology using the above-described HVHC-PEF method is in the basic research stage, and is not applied to the actual plant facilities at all, and is also at the research stage abroad. In addition, the design and fabrication of the sterilization chamber is recognized as a technology of high difficulty in advanced foreign countries, and research on this is ongoing.

Therefore, the present invention was created to solve the above problems, using a high-pressure pulsed electric field sterilization method, applying a sterilization apparatus for disinfecting biological double membranes such as living bacteria and microorganisms in fluid food in actual production and As a new sterilization chamber for processing fluid foods, it is possible to minimize the generation of air bubble bubbles generated inside and to easily manufacture with a uniform electric field, or insert a plurality of insulator rings into two electrodes of the sterilization chamber. The purpose is to control the spacing of the electrodes.

1 is a view showing a sterilization method by a high pressure pulse electric field,

2 is a block diagram of a high pressure pulse electric field sterilizer according to the present invention,

3 is a schematic configuration diagram of a high voltage power supply for charging a high voltage capacitor according to the present invention;

4 is a waveform diagram for driving a switch of the high voltage power supply according to the present invention,

5 is a voltage waveform diagram of the exponential function applied to the sterilization chamber according to the present invention,

6 is a schematic configuration diagram of a high electric field sterilizer having a square wave forming circuit according to the present invention;

7 is an embodiment of a square wave forming circuit according to the present invention,

8 is a diagram illustrating a turn on and a turn off operation mode of cyratron according to the present invention;

9 is a cross-sectional view of a flow type sterilization chamber according to the present invention;

10 is a cross-sectional view of the coaxial sterilization chamber according to the present invention.

※ Explanation of code for main part of drawing

1: Power supply part PS 2: Cyratron driving circuit part (PG)

3: low pass filter (LF) 4: cyratron heating transformer (TRS)

5: first high pressure partial pressure unit (HVD1) 6: sterilization chamber (CH)

7: second high voltage dividing unit (HVD2) 8: pulse forming unit (PFC)

L1: Current limiting inductor C1, C2: Capacitor

S1: Thyratron 11: Inverter

12: high voltage transformer (HVT) 13: high voltage rectifier (HVR)

200: flow chamber 300: coaxial chamber

201, 202, 304: internal electrode 301: external electrode

203, 303, 306: insulator 204, 302: inlet

205: outlet 206, 305: cooling tube

207, 208, 209: support 210: insulator ring

High system sterilization apparatus according to the present invention for achieving the above object, in the sterilization apparatus, high pressure supply means for supplying a high pressure power; Conversion means for converting and outputting the type of the high pressure supplied; And a sterilization chamber for sterilizing by forming an electric field according to the converted high pressure.

In the sterilization chamber, a high-temperature sterilization flow-type chamber according to the present invention comprises: an electric field forming unit for sterilizing a fluid by forming a high-pressure electric field between two internal electrodes; An adjusting unit for extrapolating between the two internal electrodes to adjust the spacing of the electrodes; An inlet through which the fluid to be sterilized in communication with the electric field forming unit is introduced; And a discharge port through which the sterilized fluid is discharged in communication with the electric field forming unit, and the high-pressure sterilizing coaxial chamber according to the present invention is a sterilizing chamber. An electric field forming part which sterilizes a fluid by forming an electric field of high pressure between the outer electrode and the rod-shaped inner electrode; An inlet port in which fluid to be sterilized in communication with the electric field forming unit is drawn in, and an inner wall surface thereof is formed in a diagonal shape; And an outlet through which the sterilized fluid is discharged in communication with the electric field forming unit.

The high-pressure sterilization apparatus and the sterilization chamber according to the present invention configured as described above apply the high pressure supplied by the high pressure supply means to the sterilization chamber, wherein the conversion means has an exponential function or When the output is converted to a square wave, the fluid is sterilized by forming an electric field in the sterilization chamber according to the converted high pressure. Here, the sterilization chamber forms a high-pressure electric field between two internal electrodes to form the fluid. Sterilization and flow chamber that can control the gap between electrodes by inserting insulation between electrodes, or coaxial type to sterilize fluid by forming high pressure electric field between outer electrode and coarse inner electrode surrounding coaxial body Chamber.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of a high-pressure sterilization apparatus and a sterilization chamber according to the present invention will be described in detail.

2 is a configuration diagram of a high electric field sterilizer according to the present invention, which includes a high pressure power supply device 1 for boosting and supplying input DC power according to alternating switch control signals Q1 to Q4; A first capacitor C1 storing the high voltage; Current limiting inductor (L1) for limiting the current output from the first capacitor (C1); A drive pulse generator 2 outputting a drive pulse according to the input control signal Control; A low band filter 3 for filtering high voltage noise generated during switching; Cyrattron (S1) for discharging the high pressure charged in the second capacitor (C2) in accordance with the drive pulse passed through the filter input to the grid (G) terminal; A transformer (4) for heating the cathode (K) of the cyratron (S1); First and second high pressure voltage dividers (HVD1,2) (5,7) for dividing the supplied high pressure; A second capacitor (C2) for applying the supplied high pressure exponentially to the sterilization chamber (6); It comprises a sterilization chamber (6) for forming and sterilizing the electric field according to the applied high pressure. Here, the sterilization chamber 6 is inserted into an insulator ring between two electrodes to which a voltage of several kV to several tens of kV is applied to prevent the flow type sterilization chamber or bubble bubbles, which can control the size of the electric field, Coaxial sterilization chamber with electric field distribution and smooth fluid flow. The first capacitor C1 is a capacitor for charging the high voltage power output from the high voltage power supply 1, and the current limiting inductor L1 limits the current output from the first capacitor C1. . The driving pulse generator 2 outputs a driving pulse according to the input control signal Control, and inputs the driving pulse to the grid G terminal of the cyratron S1 through the high pressure noise filter 3. Sairatron (S1) is supplied to the chamber the high pressure charged in the second capacitor in accordance with the driving pulse passed through the high-pressure noise filter (3). The transformer 4 heats the cathode K of the cyratron S1.

9 and 10 are cross-sectional views of the flow type and coaxial sterilization chambers according to the present invention, with reference to the high electric field sterilization apparatus of FIG.

The present invention is a device for sterilizing several to several liters per minute at about 45 ℃ or less using the high-system sterilization method shown in Figure 1, the high-power system according to the electric field application method, such as exponential wave form and square wave method It can be divided into

Figure 2 is an embodiment of the high-power sterilization apparatus of the exponential function type, first, the high-voltage power supply for charging the capacitor (1) is to boost the input voltage to a high voltage by using a high voltage transformer and then rectified it to the first capacitor (C1) Will be used as input.

3 is a schematic configuration diagram of a high voltage power supply 1 for charging a high voltage capacitor, wherein the high voltage power supply 1 converts input power according to an alternately input switch control signal. ; A high voltage transformer (HVT) 12 which boosts the electric power of the primary side and induces the secondary side; And a high voltage rectifier (HVR) 13 for rectifying the power induced in the secondary side to flow in one direction. Here, the inverter 11 switches to pass the input voltage are alternately _{(Q 1, Q 2, Q} 3, Q 4), said switch _{(Q 1, Q 2, Q} 3, Q 4) each antiparallel Diodes (D ₁ , D ₂ , D ₃ , D ₄ ) and capacitors (C ₁ , C ₂ , C ₃ , C ₄ ) connected in parallel across the switches (Q ₁ , Q ₂ , Q ₃ , Q ₄ ) Doing.

In other words, the high voltage power supply 1 is a power supply for charging the first capacitor C1, and includes an inverter 11, a high voltage transformer 12, and a high voltage rectifier 13. The supply device 1 performs pulse width control of the output voltage by providing a phase difference between the advance leg switches and the ground leg switches. That is, the high voltage power supply 1 uses a series resonant inverter 11 because the input power must be transmitted to the output through a high impedance transformer having a large impedance, and the control of the inverter 11 is a phase shift ( Phase shift) Pulse Width control is used. The high voltage transformer 12 uses a ferrite core wound around the bobbin, and is manufactured in consideration of the winding ratio due to insulation and voltage ratio loss. The high-voltage rectifier 13 is a method of rectifying directly by using a high-voltage diode, wherein the high-voltage DC voltage should be detected so as not to be affected by the capacitance component of the earth using R and C voltage dividers.

4 is a waveform diagram for driving a switch of the high voltage power supply 1, which is an alternating square wave voltage, and the square wave voltage becomes a high frequency voltage of a sine wave while passing through a resonance capacitor and a transformer leakage inductance, which is a high voltage transformer. It is boosted by (12) and delivered. At this time, the amount of resonant current delivered to the output is linearly added or subtracted according to the pulse width, and thus a constant output voltage is controlled.

The output of the high voltage transformer 12 is a constant DC voltage by the high voltage rectifier 13. On the other hand, the DC voltage is constantly controlled and when the later stage of the latron (S1) is turned on, the operation of the high-voltage power supply (1) can be stopped so that the natural firing of the thyraltron is achieved. If the operation of the input high-voltage power supply is linked to the Cyrattron, the first capacitor and the inductors L1 and D1 are unnecessary.

On the other hand, the current limiting inductor (L1) is connected to the rear end of the first capacitor (C1) in order to limit the peak value of the current charged in the first capacitor (C1). The second capacitor C2 is a device for applying a high pressure to the sterilization chamber 6 after the high pressure is charged, and the first and second voltage dividers 5.7 divide the high pressure.

Cyrattron S1 serves to instantaneously supply energy charged in the second capacitor C2 to the sterilization chamber as a load. That is, when the cyratron S1 is turned on, the second capacitor C2 is turned on. ) Is connected in parallel to the chamber to supply charging energy to the load. That is, according to the input control signal Control, the driving pulse of the high voltage and high current is output from the driving pulse generator 2 and input to the grid terminal, and the turn-on and turn-off of the cyratron S1 are controlled.

Sairatron (S1) is a hot cathode grid-controlled discharge tube, one or two grid (G) is put into the discharge path of the hot cathode rectifier discharge tube, between the anode (A)-cathode (K) by the grid (G). It is a discharge tube to control the operation of the power source, and with a slight grid input, relatively large power control is possible, the operation is sure, and the response speed is extremely fast. In addition, the thyrrone (S1) can be used by replacing the pulse thyristor.

FIG. 5 is an exponential voltage waveform diagram applied to a sterilization chamber. In the exponential voltage applied voltage waveform, an actual sterilization region has a t _P section, that is, when the maximum applied voltage is 1, an applied voltage is about 0, It is until it reaches 57V _{L. In} this section, the double layer such as bacteria is destroyed by the high pressure electric field, and the sterilization effect is shown.

6 is a schematic configuration diagram of a high electric field sterilizing apparatus having a square wave forming circuit, and FIG. 7 is an embodiment of the square wave forming circuit. The square wave method is difficult to design and configure a sterilizing apparatus, but the sterilization efficiency is the exponential function. It has the advantage of being superior to the method. Therefore, as shown in FIG. 7, another embodiment of the present invention may be added to convert the applied waveform into a square wave in order to increase the sterilization efficiency of the high electric field sterilizer. 6, the square wave forming circuit of FIG. 7 is added in place of the second capacitor C2 in the sterilizer configuration of FIG. 2, and the capacitor and the inductor are connected in parallel to the second capacitor C2 of FIG. 2. By forming a square wave, a high pressure is applied to the sterilization chamber. The input high-voltage power supply charges the pulse-forming circuit directly and stops operation when the cyratron turns on, causing the cyratron to naturally burn out.

FIG. 8 is an equivalent circuit diagram illustrating a turn-on and turn-off operation mode of the cyratron S1, that is, the same according to the turn-on and turn-off of the cyratron S1. In this case, it can be seen that the charging voltage of the second capacitor C2 is applied to the sterilization chamber 6. In addition, it can be seen that the first capacitor C1 charges the second capacitor C2 when the cyratron S1 is turned off.

Here, as described in the previous section, the first capacitor and the inductor L1 are unnecessary when the operation of the input power supply is performed in conjunction with the on and off operation of the cyratron.

Meanwhile, the sterilization chamber 6 is a mechanism for injecting an object to be sterilized and forms a high electric field to sterilize. The high pressure of the high voltage power supply 1 is applied to both electrodes of the sterilization chamber. It is meant to be built. The structure and shape of the sterilization chamber 6 has a great influence on the sterilization effect.

9 is a cross-sectional view of the flow type sterilization chamber 200, an electric field forming unit for sterilizing the fluid by forming an electric field of high pressure between the two internal electrodes (201, 202); An adjusting unit 210 which is extrapolated between the two internal electrodes 201 and 202 to adjust the spacing of the electrodes; An inlet opening 204 in communication with the electric field forming unit for introducing a fluid to be sterilized; And an outlet 205 through which the sterilized fluid is discharged in communication with the electric field forming unit, wherein an insulator ring is inserted between the internal electrodes 201 and 202 to physically adjust the gap of the electrode. Fluid food injected through 204 is sterilized as it is pumped upwards, passing a constant field region between the two electrodes 201 and 202.

The flow type sterilization chamber has a much simpler structure than the form proposed in the prior art or the literature, and is characterized by easy manufacturing. In particular, since the conventional chambers have a constant electrode spacing and cannot change the electrode spacing, each chamber has to be replaced with a new chamber every time the load is slightly changed, that is, every time the sterilized food is changed. A plurality of insulator rings may be inserted between the two electrodes to physically adjust the gap of the electrodes. For example, fluid food passes between the two electrodes 201 and 202, and a plurality of insulator rings 210 are inserted between the two electrodes and a tube through which the fluid food passes, thereby physically adjusting the gap of the electrodes. .

The flow type sterilization chamber is composed of two electrodes 201 and 202 and is separated by an insulator ring 210. The insulator ring 210 is positioned outside the portion where the electric field is concentrated between the electrodes. The inlet 204 of the fluid food is located between the two electrodes, and the fluid food is discharged to the two outlets 205 between the electrodes to which a uniform high pressure electric field between the two electrodes 201 and 202 is applied. In addition, the tube 206, through which the coolant flows, passes through the inside of the electrode for cooling the sterilization chamber. The structures 207, 208, and 209 other than the above are supports such as a case and a bolt for supporting the sterilization chamber.

10 is a cross-sectional view of the coaxial sterilization chamber 300, in which a high-pressure electric field is formed between an outer electrode 301 surrounding a coaxial body and a rod-shaped inner electrode 304 to sterilize the fluid. Electric field forming unit; An inlet 302 in which fluid to be sterilized in communication with the electric field forming unit is drawn in, and an inner wall thereof is diagonally formed; And an outlet through which the sterilized fluid is discharged in communication with the electric field forming unit, wherein the coaxial chamber is oblique to the front wall of the inlet 302 so that no air bubbles are generated by the pressure when the fluid is input. Gave the slope of. In addition, an internal water cooling rod is disposed inside the copper plate, which is the internal electrode 304, for cooling the sterilization chamber.

The fluid injected through the input nozzle in the coaxial chamber 300 is sterilized while passing through an electrode in which a high-pressure electric field is densely distributed. That is, before sterilization, the fluid food enters both inlets 302 at a constant flow rate by an external pump, and receives a constant electric field while passing between the inner electrode 304 and the outer electrode 301. The sterilized food is then taken out again through the exit.

The coaxial chamber 300 has a structure in which a uniform electric field is distributed between the two electrodes, and prevents air bubbles from occurring in the fluid, and also has an electrode 301 surrounding the outside and an electrode 304 having an internal rod structure. ), And is introduced through the inlet 302 of the food. The insulator 303 surrounds a portion discharged after the sterilization process of the fluid food by the high electric field, and the internal electrode 304 has a structure of a rod, which is a copper-based conductor, is supported by the insulator 306, and the internal electrode. Cooling medium for cooling enters inside 304. The external electrode 301 is made of stainless steel, and the lower insulator 306 is made of an epoxy-based insulator.

High system sterilization apparatus and sterilization chamber according to the present invention configured as described above. By implementing a high-temperature sterilization device using high-voltage, high-current pulsed electric field treatment technology, and a sterilization chamber with physically adjustable electrode spacing, the electric field is uniform, easy to manufacture, and has the same sterilization effect as before with low energy. It is a useful invention with higher sterilization efficiency.

Claims (10)

In the sterilizer, High pressure supply means for supplying high voltage power; Conversion means for converting and outputting the type of the high pressure supplied; And High field sterilization apparatus comprising a sterilization chamber for forming and sterilizing the electric field according to the high pressure to be converted output. The method of claim 1, The high pressure supply means is a high voltage power supply for charging a capacitor, A high frequency series resonant inverter for converting input power into AC power according to an alternately input switch control signal; A high voltage transformer for boosting the AC power on the primary side to guide the secondary side; And High-pressure sterilizer characterized in that it comprises a high-pressure rectifier for rectifying the flow induced in the secondary direction in one direction. The method of claim 2, The high pressure supply means when the high-voltage power supply for charging the capacitor to supply a constant DC power without the operation is turned on or off in accordance with the on, off of the siratron, A capacitive element for storing the supplied high voltage power; and And an inductive element limiting the peak value of the current output from the capacitive element. The method of claim 1, The converting means includes a thyratron or a pulse thyristor for determining whether to discharge a capacitor under control of a driving circuit unit, and the high voltage system converts the supplied high voltage into an exponential function. Sterilizer. The method of claim 1, The converting means is a high electric field sterilizer characterized in that it comprises a pulse forming circuit for converting the supplied high-voltage to a square waveform. In the sterilization chamber, An electric field forming unit which sterilizes a fluid by forming an electric field of high pressure between two internal electrodes; A spacing controller configured to extrapolate between the two inner electrodes to adjust a spacing of the electrodes; An inlet through which the fluid to be sterilized in communication with the electric field forming unit is introduced; And A high-temperature sterilization flow-type chamber configured to include an outlet through which the sterilized fluid is discharged in communication with the electric field forming unit. The method of claim 6, A high-pressure sterilization flow-type chamber, wherein a cooling tube for inflow and outflow of a cooling medium is formed inside the electric field formation part to prevent overheating of the chamber. The method of claim 6, The gap adjusting unit is a high-pressure sterilization flow-type chamber, characterized in that the plurality of insulator ring inserted between the two internal electrodes. In the sterilization chamber, An electric field forming unit for forming a high pressure electric field between a rod-shaped inner electrode and an outer electrode surrounding the inner electrode at a predetermined distance from the outside in a coaxial manner to sterilize the fluid; An inlet which is in communication with one side of the electric field forming unit and has a communication surface formed in an oblique shape to introduce a fluid to be sterilized; And The high-frequency sterilization coaxial chamber configured to communicate with the other side of the electric field forming part, and including an outlet through which the sterilized fluid is discharged while passing through the electric field forming part. The method of claim 9, A high-pressure sterilizing coaxial chamber, wherein a cooling tube for inflow and outflow of a cooling medium is formed inside the internal electrode to prevent overheating of the chamber.