RU130224U1 - Microwave sterilizer - Google Patents

Abstract

1. Microwave sterilizer, including a waveguide connected to a microwave generator with a sterilization chamber located in the waveguide, as well as an electrolyzer located on the inlet side of the sterilization chamber, one of the electrodes of which is located on the outside of the waveguide, and the second is formed by a part of the waveguide surface made with openings for passage of the medium to be sterilized and bounded on the side of the internal surface of the waveguide by the walls of the sterilization chamber, which is made in the form of a volumetric part, the internal cavity of which is formed The longitudinal channel is located in the transverse channel relative to the direction of electromagnetic radiation, while the longitudinal channel is located on the side of the medium at the location of the electrode with holes, the transverse channel is made in a tube located at an angle of 30-45 ° to the waveguide wall with the electrode characterized in that the tube has a flattened shape, is installed with the wide side to the direction of propagation of the electromagnetic wave and has a height S equal to 0.12-0.14 wavelengths and a width L equal to 0.26-0.45 wide waveguide, and the holes in the wall of the waveguide for passage of the sterilized medium are made in the form of slots with an increase in their width from the central part of the electrode to its periphery. 2. The microwave sterilizer according to claim 1, characterized in that the tube is located in the region of the maximum electric component of the electromagnetic field. The microwave sterilizer according to claim 1, characterized in that the ratio of the area of the electrode, which is part of the surface of the waveguide located in the longitudinal channel of the sterilization chamber, to the cross-sectional area of the channel is 20-100, and �

Description

The inventive utility model relates to the field of sterilization of liquid food products and can be used in the food, medical and microbiological industry, as well as in the service sector, mainly for sterilization of small volumes of various liquids (in small cafes, shops, pharmacies, doctors' offices, etc. .).

A device for disinfecting and heating aqueous media (AS USSR No. 1139439), comprising a microwave generator, a rectangular waveguide with flanges, a tube of radiolucent material, located at an angle of 30-45 ° to the wide wall of the waveguide, an end coordinated absorbing load of a quasi-resonator type. The tube in cross section has a flat shape and is installed with the wide side to the direction of propagation of the electromagnetic wave, has a height equal to 0.12-0.14 wavelengths, and a width equal to 0.26-0.45 of the size of the wide waveguide wall.

The main disadvantage of this device is the lack of an electrolytic cell, which reduces the efficiency of liquid processing.

A device for sterilizing liquids (AS USSR No. 996334) containing a microwave electromagnetic energy generator, a waveguide, a sterilization chamber located in it, connected to an electrolyzer is known. The sterilization chamber consists of a transitional and cylindrical parts. Part of the surface of the waveguide, limited by the transitional part of the sterilization chamber, is the electrode of the electrolyzer and is provided with openings for the passage of liquid.

However, in this device, microwave energy may not be completely absorbed by the gas-liquid mixture in the cylindrical part of the sterilization chamber, which negatively affects the efficiency of the process and the productivity of the device.

The task and the technical result are to increase the reliability of sterilization.

The problem is solved in that in a microwave sterilizer including a waveguide connected to a microwave generator with a sterilization chamber located in the waveguide, as well as an electrolyzer located on the side of the entrance to the sterilization chamber, one of the electrodes of which is located on the outside of the waveguide, and the second is formed by a part of the surface of the waveguide made with holes for passage of the medium to be sterilized and bounded on the side of the inner surface of the waveguide by the walls of the sterilization chamber, which is made in the form of a volumetric det whether, the internal cavity of which is formed from a longitudinal channel passing into a transverse channel with respect to the direction of electromagnetic radiation, while the longitudinal channel is located on the side of the medium at the location of the electrode with holes, the transverse channel is made in a tube located at an angle of 30-45 to According to the technical solution, the tube’s wall with the electrode has a flattened shape, is installed with the wide side to the direction of propagation of the electromagnetic wave, and has a height S equal to 0.12-0.14 lengths the width of the waveguide, and the holes in the waveguide wall for passage of the medium to be sterilized are made in the form of slots with an increase in their width from the central part of the electrode to its periphery. The sterilization chamber is made of radiolucent material. The tube is located in the region of the maximum electric component of the electromagnetic field. The ratio of the area of the electrode, which is part of the surface of the waveguide located in the longitudinal channel of the sterilization chamber, to the cross-sectional area of the channel is 20-100, and the ratio of the height of the longitudinal channel h to the height of the waveguide b is 0.10-0.30. One or both electrodes of the electrolyzer can be made of silver or coated with silver.

The openings in the waveguide wall for passage of the medium to be sterilized have a width w and a length (and are arranged sequentially one after another between the narrow walls of the waveguide to form a chain. In this case, the chains are arranged in several rows on the electrode, which is the wall of the waveguide, and the slots are made with increasing length from the central part of the electrode to its periphery The ratio of the width of the slit w to its length (in the central part of the electrode is 1/2, and closer to the periphery - 1/3.

The essence of the proposed technical solution is illustrated by drawings, in which Fig. 1 shows an example of an installation with the inventive device, Fig. 2 shows a longitudinal section of a microwave heater combined with an electrolyzer, and Fig. 3 is a section A-A of Fig. 1.

The positions in the drawings indicate: 1 - reservoir with the original liquid; 2.6 - three-way valve; 3 - microwave heater; 4 - electrolyzer combined with a microwave heater; 5 - recuperator; 7 - a hydraulic highway; 8 - pump; 9-one-way valve, 10 - waveguide, 11 - holes in the wall of the waveguide acting as an electrolyzer, 12 - electrolyzer electrode, 13 - current lead, 14 - body, 15 - fitting, 16 - fluoroplastic screws, 17 - rubber gaskets, 18 - camera sterilization, 19 - output fitting, 20 - the beyond device, 21 - flanges.

In the claimed technical solution (Figs. 1-3), the processing of liquids infected with spore-forming forms of microorganisms is carried out without increasing pressure and at a temperature below 100 ° C in a microwave sterilizer (microwave heater) combined with an electrolyzer, synchronizing the power of the microwave generator and electrolyzer. The inventive device can be used in an installation for sterilization of liquid (figure 1). In this case, the influence of microwave energy on the processed liquid and electrolysis can be carried out with preliminary heat recovery without the use of an additional source of heating and cooling, which increases the productivity of the device and installation as a whole and reduces energy costs. In this case, the sterilizer has valves for the selection of both heated and cooled liquids and a recycle loop that does not include a reservoir with the original liquid. The presence of valves improves the operating conditions of the sterilizer, and the recycle loop (without a reservoir with the initial liquid) has a small volume, which ensures rapid heating of the liquid during sterilization of hydraulic lines, which in turn reduces the time of this operation and the output to a given temperature regime. When replacing fluids, sterilization is carried out on the hydraulic circuits, recycle at a temperature of 55-90 ° C (preferably 87-90 ° C), use recovery.

The installation diagram, in which the inventive device can be built-in (Fig. 1), includes a hydraulic line connected to a container 1 with a source liquid, to which a pump 8, a microwave sterilizer (microwave heater) 3, are connected through a one-way valve 9, combined with the electrolyser 4. A recuperator 5 is also connected to the hydraulic line 5. The hydraulic line 7 with respect to the microwave sterilizer 3 is divided into input and output lines (the input line is located in front of the microwave heater, the output line is after), while the heat exchanger 5 is formed with accommodating parts of the input and output lines. Two three-way valves 2 and 6 are built into the hydraulic line from the output line side, one of which is located in front of the recuperator 5, and the second after it, and designed to drain hot and cooled liquid media, respectively. In this case, the output line is connected to the input (to the input of the pump 8) with the formation of a closed loop.

The microwave sterilizer 3 consists of a waveguide 10 connected to a microwave electromagnetic energy generator (not shown), located in the waveguide 10 of the sterilization chamber 18, in which the electrolyzer 4 is located. The sterilization chamber 18 is made in the form of a volumetric part made of a material permeable to microwave electromagnetic radiation, and consists of a transitional and output parts, an output fitting 19, an off-limit device 20. The transitional part includes a longitudinal channel passing into a transverse channel located in the output part. In this case, the cell is located in the transitional part with the formation of a longitudinal channel. One of the electrodes of the electrolyzer is a part of the surface of the waveguide 10, limited on the side of its inner surface by the wall of the transitional part of the sterilization chamber 18, and is provided with openings 11 for the passage of liquid. The second electrode 12, equipped with a current lead 13, is located outside the waveguide 10 and is mounted in a housing 14 made of dielectric material. The housing 14 and the transition part of the sterilization chamber 18 are attached to the waveguide wall by means of fluoroplastic screws 16 and rubber gaskets 17 for sealing the elements of the device. The housing 14 is connected to the fitting 15 for supplying the processed fluid to the microwave sterilizer. The ratio of the area of the electrode, which is part of the surface of the waveguide located in the longitudinal channel of the sterilization chamber, to the cross-sectional area of the channel is 20-100 with the ratio of the height of the transition part h to the height of the waveguide b 0.10-0.30. The output part of the sterilization chamber is made in the form of a flat tube installed with the wide side to the direction of propagation of the electromagnetic wave, has a height S equal to 0.12-0.14 wavelengths and a width L equal to 0.26-0.45 wide wall sizes waveguide.

The holes 11 in the wall of the waveguide for passage of the sterilized medium are made in the form of slots, the geometry and location of which are presented above. It was experimentally shown that the ratio of the gap width w to its length (in the central part of the electrode is 1/2, and closer to the periphery - 1/3.

Sterilization and heating of liquids is as follows. The liquid from the tank 1 through the valve 9 is sucked up by the pump 8 and fed through the recuperator 5 to the microwave sterilizer (microwave heater) 3, combined with the electrolyzer 4. The sterilized water through the nozzle 15 is fed into the space formed by the electrode 12 and the lower plane of the waveguide 10. B As a result of electrolysis, finely dispersed oxygen and hydrogen are evenly distributed in water, which through holes 11 enters the sterilization chamber 18, where it is exposed to microwave electromagnetic radiation. In addition to the thermal effect, finely dispersed oxygen exerts a sterilizing effect, which under the influence of the microwave field transforms into a singlet state. There is a cavitation effect arising due to gases dissolved in water. The leakage of microwave energy from the waveguide is prevented by the out-of-order device 20. After heating, the liquid is taken out through the three-way valve 2 in hot form, for example, for making tea, coffee or chilled after the recuperator 5 through the three-way valve 6. When sterilizing the hydraulic lines, the liquid fills the hydraulic pipe with pump 8 closes valve 9 and the liquid circulates in a closed loop of the recycle, heating in the microwave sterilizer 3 with the electrolyzer 4. The temperature of the liquid is controlled by a thermometer;

after processing the hydraulic line, the liquid is drained through valve 2 or 6.

As a result of reducing the limiting effect of the electrolysis stage on the process as a whole, it is possible to increase the productivity of the proposed device by 2–3 times with an adequate degree of sterilization.

Examples of the utility model, confirming the achievement of the claimed result. A 1000 W microwave generator operating at a frequency of 2450 ± 50 MHz was used as the main technological tool. The waveguide tract has a cross section of 45 × 90 mm or 34 × 72 mm.

Example 1

Pre-dechlorinated tap water was infected with a spore-forming form of Vas. Thuringiensis microorganisms at a concentration of 1200 CFU / ml and was subjected to the combined influence of microwave energy and electrolysis at a current of 0.75 A. The technological parameters of this process are presented in Table 1. The parameters were fixed and biocontrol samples were taken at discrete values of temperature from 90 to 40 ° С.

Table 1 Technological parameters of the combined treatment of water infected with you. Thuringiensis microwave energy and electrolyzer at a current of 0.75 A water starts from water con ° C Q water ml / min R microwave imp. Tue Il-ra A U el B VSWR With ost CFU / ml 20,0 90 170 794 0.75 10.0 2.6 0 20,0 87 175 805 0.75 10.0 2.6 0 20,0 85 185 815 0.75 10.0 2,5 60 20,0 80 205 830 0.75 10.0 2,4 600

20,0 70 255 864 0.75 10.0 2.1 1000 20,0 60 325 890 0.75 10.5 2.0 1200 20,0 fifty 475 935 0.75 11.0 1.7 1200 20,0 40 650 937 0.75 11.0 1,6 1200

The following conventions are used in the table:

t _water - initial water temperature, ° C;

t _{water con.} - final water temperature, ° C;

Q _water - _water flow rate, ml / min;

P _microwave - microwave power absorbed by water, W;

P _rivers - water absorbed power in the recuperator, W;

I _el-RA - current of the cell, A;

U _el-ra - voltage of the cell, V;

VSWR - standing voltage wave coefficient;

With _ost - the concentration of microorganisms after microwave processing, CFU / ml .;

CFU - colony forming unit;

t _{river water} - water temperature after the recuperator, ° С.

From the tabular data it is seen that the sterilizing effect of the combined effect of microwave energy and electrolysis at a current of 0.75 A on you. Thuringiensis manifests itself at a temperature of 87 ° C. Based on the foregoing, the upper temperature regime of water sterilization is taken in the range of 87-90 ° C.

Example 2

In the same temperature range (87-90 ° C), a nutrient medium containing amino acids was processed in combination with electrolysis. The results of the analyzes are summarized in table 2.

Table 2. The amino acid content (in mg / l) in samples of the nutrient medium treated with microwave energy and electrolysis at a current of 0.75 A Aminoxylot Sample Number 1 counter 2 3 four 5 Isoleucine 0.30 - 0.31 0.33 0.31 Leucine 0.29 - 0.31 0.28 0.33

Valine 0.22 0.24 0.21 0.22 0.23 Methionine 0.15 0.20 0.12 0.11 0.12 Tyrosine 0.22 - 0.19 0.22 0.22 Phenylalanine 0.22 - 0.17 0.18 0.21 Cystine 0.21 0.20 0.16 0.14 0.15 Lysine 0.37 0.24 0.30 0.37 0.30 Histidine 0.26 - 0.21 0.19 0.22

The study of the content of free amino acids in the samples was carried out using the method of ion exchange chromatography on an automatic analyzer Likvimat Sh.

The results obtained indicate that in the studied samples of the nutrient medium, the concentrations of free amino acids are practically unchanged, which confirms the preservation of the nutritional properties of the liquid after combined treatment.

The magnetron (microwave generator) is fed through the anode circuit from a constant voltage source (according to the doubling scheme). The anode voltage is formed by half-wave rectification of an alternating voltage with a frequency of 50 Hz and higher and ferroresonant stabilization (see, for example, the circuit diagram of the Electronika household microwave oven).

The power source of the electrolyzer is also made with a half-wave rectification of an alternating voltage of 50 Hz and higher, which allows you to synchronize the half-wave (pulses) of the anode voltage and current of the microwave generator and the half-wave (pulses) of the voltage and current of the electrolyzer.

The synchronization of the two power sources allows you to simultaneously affect the microorganisms in the liquid.

Example 3

Pre-dechlorinated tap water was infected with Pseudomonas aeruginosa (Pseudomonus aeruginosa, strain No. 1) at a concentration of 10 ⁶ CFU / ml. The power of the microwave generator is 700 W, the frequency is 2450 ± 50 MHz.

After that, the water was exposed to microwave energy in the temperature range 65-55 ° C. Water temperature decreased after 1.0 ° С, while samples were taken for biocontrol and technological parameters of the heating process were recorded. The experimental results are presented in table 3.

Table 3 The primary effect of microwave energy on Pseudomonus aeruginosa introduced into water water starts from water con ° C Q water ml / min R microwave imp. Tue With ost CFU / ml 26.2 65 220 596 0 26,4 64 225 590 0 26.5 63 230 586 0 26.6 62 240 593 0 26.6 61 250 600 0 26.6 60 255 594 0 26.6 59 260 588 40 26.6 58 275 602 80 26.6 57 285 605 1.2 · 10 ² 26.6 56 290 595 1.4 · 10 ³ 26.6 55 300 600 2.0 · 10 ³

From the table it follows that the death of Pseudomonas aeruginosa is carried out at a temperature of 60 ° C.

Example 4

Viable microorganisms after the initial exposure to microwave energy at a temperature of 55 ° C were grown and introduced into previously dechlorinated tap water at a concentration of 10 ⁶ CFU / ml.

After that, the microorganisms were subjected to secondary exposure to microwave energy under the same conditions as in the previous experiment. The results are shown in table 4.

Table 4 Secondary exposure of microwave energy to Pseudomonus aeruginosa introduced into water water starts from water con ° C Q water ml / min R microwave imp. Tue With ost CFU / ml 21.7 65 215 649 0 22.1 64 217 634 0

22.1 63 220 628 0 22.2 62 223 620 0 22.2 61 225 610 0 22.2 60 230 607 0 22.3 59 240 615 0 22.3 58 245 610 0 22.3 57 255 617 thirty 22.3 56 265 623 2,1.102 22 „3 55 280 639 4.0.102

From table 4 it follows that the sterilization temperature decreased from 60 ° C (see table 3) to 58 ° C.

Example 5

The remaining viable microorganisms at a temperature of 55 ° C after a second exposure were re-grown and introduced into pre-chlorinated tap water at a concentration of 10 ⁶ CFU / ml and exposed to microwave energy for the third time. The results of the experiments are shown in table 5.

Table 5 Tertiary effect of microwave energy on Pseudomonus aeruginosa introduced into water water starts from water con ° C Q water ml / min R microwave imp. Tue With ost CFU / ml 22.0 65 215 645 0 22.0 64 220 644 0 22.1 63 225 642 0 22.2 62 230 638 0 22.2 61 235 636 0 22.3 60 240 631 0 22.4 59 245 626 0 22.4 58 250 621 0 22.5 57 260 616 0 22.5 56 270 631 0 22.6 55 280 635 2

After the third exposure, two viable cells remaining at 55 ° C were seeded, but did not multiply and died.

Thus, after a 3-fold treatment of drinking water at a temperature of 55 ° C infected with Pseudomonus aeruginosa, the death of a population of microorganisms occurs.

It should be emphasized that the remaining cells do not show an increase in resistance to the subsequent exposure to microwave energy compared with, for example, traditional heat heating.

Thus, the temperature range of sterilization of water and hydraulic lines of 5 5-90 ° C was determined from examples 1,3-5. The lower temperature limit corresponds to the death of vegetative forms of microorganisms after triple water circulation.

The upper temperature limit corresponds to the death of spore-forming forms of microorganisms with a combination of microwave energy and electrolysis in one pass of water along the hydraulic highway.

Example 6

In order to increase the productivity of liquid processing and reduce energy consumption, heat recovery is used.

The technological parameters of the microwave water heating process with recovery are presented in table 6. The power of the microwave generator is 1000 W, the frequency is 2450 ± 50 MHz.

Table 6. The process of microwave heating of water with heat recovery water starts from water con ° C Q water ml / min water starts from R rivers W UHF Tue VSWR 20,0 44 90 225 380 730 3.2 20,0 38 80 270 330 790 2.7 20,0 33 70 320 310 825 2,5 20,0 29th 60 400 260 860 2.2 20,0 26 fifty 530 220 900 1.9 20,0 23.6 40 790 200 950 1.8

In heat recovery mode, the productivity of the heating process increases by 1.22-1.32 times.

In addition, the sterilizer selects hot water (for example, for making tea, coffee, etc.) immediately after the microwave sterilizer and chilled water after the recuperator.

In addition, in the sterilizer in order to reduce the volume of water and the processing time in the circulation mode, the recycle loop does not include a reservoir with the original liquid.

In the microwave sterilizer, one or both electrodes of the electrolyzer are coated with silver to ensure simultaneous exposure of microorganisms to microwave energy, electrolysis and silver in ionic form, forming under the influence of current. In addition, the presence of silver in liquids contributes to their long-term storage after processing.

Thus, the use of the claimed combination of features allows you to:

- destroy spore-forming forms of microorganisms at a temperature of 87-90 ° C and without increasing pressure;

- prevent secondary contamination of fluids when changing;

- increase the productivity of sterilization and heating by 22-32%;

- preserve the nutritional value of liquids

- reduce energy consumption.

Claims (5)

1. Microwave sterilizer, including a waveguide connected to a microwave generator with a sterilization chamber located in the waveguide, as well as an electrolyzer located on the inlet side of the sterilization chamber, one of the electrodes of which is located on the outside of the waveguide, and the second is formed by a part of the waveguide surface made with openings for passage of the medium to be sterilized and bounded on the side of the internal surface of the waveguide by the walls of the sterilization chamber, which is made in the form of a volumetric part, the internal cavity of which is formed The longitudinal channel is located in the transverse channel relative to the direction of electromagnetic radiation, while the longitudinal channel is located on the side of the medium at the location of the electrode with holes, the transverse channel is made in a tube located at an angle of 30-45 ° to the waveguide wall with the electrode characterized in that the tube has a flattened shape, is installed with the wide side to the direction of propagation of the electromagnetic wave and has a height S equal to 0.12-0.14 wavelengths and a width L equal to 0.26-0.45 wide waveguide, and the holes in the wall of the waveguide for passage of the sterilized medium are made in the form of slots with an increase in their width from the central part of the electrode to its periphery. 2. The microwave sterilizer according to claim 1, characterized in that the tube is located in the region of the maximum electric component of the electromagnetic field. 3. The microwave sterilizer according to claim 1, characterized in that the ratio of the area of the electrode that is part of the surface of the waveguide located in the longitudinal channel of the sterilization chamber to the cross-sectional area of the channel is 20-100, and the ratio of the height of the longitudinal channel to the height of the waveguide is 0 , 10-0.30. 4. The microwave sterilizer according to claim 1, characterized in that one or both electrodes of the electrolyzer are made of silver or coated with silver. 5. The microwave sterilizer according to claim 1, characterized in that the ratio of the slit width w to its length 1 in the central part of the electrode is 1/2, and 1/3 closer to the periphery.

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