A non-thermal sterilization device for bath liquid sterilization and method of use

Abstract

The present application relates to the technical field of disinfection and sterilization equipment, and particularly relates to a non-thermal sterilization device for bath liquid sterilization and a use method, comprising: a sterilization cavity provided with a first interface and a second interface; the sterilization cavity is composed of a plurality of Tesla valve units connected in series at the head and tail, the Tesla valve unit is made of an insulating and corrosion-resistant material, the Tesla valve unit comprises two branch flow channels arranged alternately left and right, the first interface corresponds to the converging side of the branch flow channel, and the second interface corresponds to the diverging side of the branch flow channel; two metal pole pieces connected to the bottom surface and the top surface of the sterilization cavity, the two metal pole pieces can be electrically connected to a high-voltage pulsed electric field generating device; when liquid flows in from the first interface and flows out from the second interface, the high-voltage pulsed electric field generating device is turned off; when liquid flows in from the second interface and flows out from the first interface, the high-voltage pulsed electric field generating device is powered on, so that a high-voltage pulsed electric field is formed between the two metal pole pieces. The present application improves the uniformity of bath liquid sterilization.

Description

Technical Field

[0001] This invention relates to the field of disinfection and sterilization equipment technology, and in particular to a non-thermal sterilization device and its method of use for sterilizing bath liquid. Background Technology

[0002] Pulsed electric field (PEF) is a non-thermal liquid sterilization technology. Its principle is to use a strong electric field to cause irreversible electroporation of the microbial cell membrane, leading to leakage of cell contents and death. This technology has advantages such as short processing time, small temperature rise, and minimal impact on heat-sensitive components in the liquid. The sterilization effect of PEF is affected by factors such as electric field strength, liquid conductivity, microbial characteristics, and electric field uniformity. Among these, electric field uniformity directly determines whether there are "dead zones" in the sterilization process. Under ideal conditions, the electric field in the treatment chamber is uniformly distributed, and the microorganisms in each area experience the same electric field strength. When the field strength exceeds a critical value, irreversible electroporation of the cell membrane occurs, thereby achieving microbial inactivation.

[0003] In actual processing chambers, differences in geometry and fluid dielectric properties often lead to distortions in the electric field distribution. In areas with low electric field strength, microorganisms may only undergo reversible electroporation or remain completely unaffected, creating sterilization dead zones. Conventional continuous flow PEF processing chambers (especially coaxial type) present a prominent contradiction: the electric field strength is highest near the inner wall of the chamber, but the liquid flow velocity in this area is lowest. The long liquid residence time and excessively high electrotreatment intensity near the wall, coupled with the high liquid flow velocity and insufficient treatment intensity in the central area, result in both overtreatment and undertreatment, thus limiting the uniformity of sterilization.

[0004] The turbulence generation mechanism of existing devices is embedded in a fixed geometry, and its function is irreversible: regardless of whether sterilization is required, the liquid flow is forcibly converted into a turbulent state as it passes through the processing chamber. In CIP cleaning or simple transport stages, these devices still generate high flow resistance and shear forces, resulting in energy waste and potentially damaging shear-sensitive components. To circumvent these problems, the production line needs to be equipped with bypass piping and valve matrices, increasing hardware costs, cleaning dead zones, and hygiene hazards.

[0005] (2) The efficiency improvement mechanism is too simple. Current technologies optimize sterilization solely through single-phase fluid mixing, relying entirely on the electroporation effect of pulsed electric fields for the sterilization mechanism. For highly resistant microorganisms (such as bacterial spores and fungal spores), increasing the electric field strength or pulse number only leads to increased energy consumption, uncontrollable temperature rise, and potential damage to heat-sensitive components. The resulting turbulence is often large-scale eddies, resulting in insufficient microscopic radial mixing. The mixing elements themselves may create new low-velocity zones, making it difficult to eliminate sterilization dead zones.

[0006] (3) High manufacturing costs and high operating energy consumption Structures such as vortex chambers, static mixers, and spiral flow channels require high machining precision and necessitate the use of special insulating materials, resulting in high manufacturing costs. Forced induced turbulence generates significant pressure drops, requiring high-power delivery pumps and leading to high energy consumption during long-term operation. Internal components are prone to clogging and scaling, resulting in high maintenance costs. Summary of the Invention

[0007] The present invention aims to at least solve one of the technical problems existing in the related art. To this end, the present invention provides a non-thermal sterilization device for sterilizing bath liquid, which solves the technical problems of uneven electric field distribution and over-treatment and under-treatment in existing high-voltage pulse electric field treatment chambers, and improves the uniformity of bath liquid sterilization.

[0008] This invention provides a non-thermal sterilization device for sterilizing bath liquid, comprising: The sterilization chamber has a first interface and a second interface at both ends, and the first interface or the second interface can be connected to a rotor pump. The sterilization chamber is composed of several Tesla valve units connected in series. The Tesla valve units are made of insulating and corrosion-resistant materials. Each Tesla valve unit includes two branch channels arranged alternately on the left and right. The first interface corresponds to the converging side of the branch channel, and the second interface corresponds to the diffuser side of the branch channel. Two metal electrodes are connected to the bottom and top surfaces of the sterilization chamber, and the two metal electrodes can be electrically connected to a high-voltage pulse electric field generator. When liquid flows in from the first port and out from the second port, the high-voltage pulse electric field generator is turned off; when liquid flows in from the second port and out from the first port, the high-voltage pulse electric field generator is energized so that a high-voltage pulse electric field is formed between the two metal electrodes.

[0009] A further improvement of the non-thermal sterilization device for sterilizing bath liquid of the present invention is that the cross-section of the branch channel is rectangular and the width of the branch channel is 15~25mm.

[0010] A further improvement of the non-thermal sterilization device for sterilizing bath liquid of the present invention is that the inlet length or outlet length of the branch channel's diversion island is 40~50mm, the straight section length of the branch channel is 100~120mm, and the radius of curvature of the center line of the return bend of the branch channel is 44~46mm.

[0011] A further improvement of the non-thermal sterilization device for sterilizing bath liquid of the present invention is that the diversion angle of the diversion island is 40°~60°.

[0012] A further improvement of the non-thermal sterilization device for sterilizing bath liquid of the present invention is that the number of series stages of the plurality of Tesla valve units is 1 to 10.

[0013] A further improvement of the non-thermal sterilization device for sterilizing bath liquid of the present invention is that the metal electrode is made of stainless steel or titanium alloy.

[0014] A further improvement of the non-thermal sterilization device for sterilizing bath liquid of the present invention is that the surface of the metal electrode is electrolytically polished.

[0015] A further improvement of the non-thermal sterilization device for sterilizing bath liquid of the present invention is that the distance between the two metal electrodes is 15~25mm.

[0016] A method of using a non-thermal sterilization device for sterilizing bath liquid includes the following steps: Connect the first interface to the rotor pump, and connect the high-voltage pulse electric field generator to the two metal poles; When used as an infusion line, the rotor pump is controlled to rotate forward, and the liquid flows into the sterilization chamber from the first port and flows out from the second port. When sterilization is required, the rotor pump is reversed, and the liquid flows into the sterilization chamber from the second port and flows out from the first port. The liquid generates turbulence and bubbles in the Tesla valve unit. At the same time, the high-voltage pulse electric field generator is energized to apply a high-voltage pulse electric field between the two metal electrodes, so that the liquid in the sterilization chamber is sterilized by the high-voltage pulse electric field.

[0017] This invention discloses a non-thermal sterilization device for bath liquid sterilization. During use, a rotor pump changes the liquid flow direction, allowing for instantaneous switching between "low-resistance delivery" and "turbulent sterilization" modes without the need for bypass piping. When the rotor pump rotates forward, liquid flows in from the first port and out from the second port, operating in low-resistance delivery mode. In this mode, the liquid flow is stable with minimal pressure drop, suitable for either bath liquid delivery or gentle electrotreatment. When the rotor pump rotates in reverse, liquid flows in from the second port and out from the first port, operating in turbulent sterilization mode. In this mode, turbulence and microbubbles are generated within the sterilization chamber, enabling highly efficient sterilization in conjunction with a high-voltage pulsed electric field. The turbulence induced by the Tesla valve unit during reverse flow disrupts the laminar parabolic velocity profile, resulting in a uniform liquid velocity field distribution. Two parallel metal electrodes provide a geometrically uniform electric field, which, combined with the uniform velocity field, ensures that microorganisms in all areas of the liquid receive similar electrical pulse doses, thus resolving the coexistence of "overtreatment" and "undertreatment" issues in traditional treatment chambers. The microbubbles generated online in the reverse turbulent sterilization mode have the following effects: when microbubbles with low dielectric constant are suspended in liquids with high dielectric constant, they will generate a local electric field enhancement effect in the equatorial region of the bubble, allowing nearby microorganisms to withstand a higher effective field strength; under the action of a high-voltage pulsed electric field, the microbubbles will oscillate or collapse, generating shock waves and microjets, which, in synergy with the electroporation effect, can improve the inactivation effect on stubborn microorganisms such as spores.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a non-thermal sterilization device for sterilizing bath liquid provided by the present invention.

[0021] Figure 2 This is a schematic diagram of a non-thermal sterilization device for sterilizing bath liquid provided by the present invention in normal flow and sterilization states.

[0022] Figure 3 This is a schematic diagram of the use of a non-thermal sterilization device for sterilizing bath liquid provided by the present invention.

[0023] Figure label: 1. Sterilization chamber; 2. First interface; 3. Second interface; 4. Positive metal electrode; 5. Negative metal electrode; 6. Tesla valve unit; 71. First branch channel; 72. Second branch channel; 8. Diverter island; 9. High-voltage pulse electric field generator; 10. Rotary pump. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. The following embodiments are used to illustrate this invention but should not be used to limit the scope of this invention.

[0025] The following is combined with Figure 1 and Figure 3 The present invention describes a non-thermal sterilization device for sterilizing bath liquid, comprising: The sterilization chamber 1 has a first interface 2 and a second interface 3 at both ends, and the first interface 2 or the second interface 3 can be connected to the rotor pump 10. The sterilization chamber 1 is composed of several Tesla valve units 6 connected in series. The Tesla valve unit 6 is made of insulating and corrosion-resistant material. The Tesla valve unit 6 includes two branch channels arranged alternately on the left and right. The first interface 2 corresponds to the converging side of the branch channel, and the second interface 3 corresponds to the diffusion side of the branch channel. Two metal electrodes are connected to the bottom and top surfaces of the sterilization chamber 1, and the two metal electrodes can be electrically connected to the high-voltage pulse electric field generator 9. When liquid flows in from the first port 2 and out from the second port 3, the high-voltage pulse electric field generator 9 is turned off; when liquid flows in from the second port 3 and out from the first port 2, the high-voltage pulse electric field generator 9 is energized so that a high-voltage pulse electric field is formed between the two metal electrodes, thereby performing a non-thermal sterilization operation on the liquid.

[0026] Furthermore, the two branch channels are the first branch channel 71 and the second branch channel 72, respectively. The cross-sections of the first branch channel 71 and the second branch channel 72 are both rectangular, with a channel width of 15~25mm and a channel height of 15~25mm.

[0027] Preferably, the flow width of the first branch channel 71 and the second branch channel 72 can be selected as 15mm, 20mm, or 25mm.

[0028] Furthermore, the inlet or outlet length of the branch channel's diversion island is 40-50 mm, the straight section length of the branch channel is 100-120 mm, and the radius of curvature of the centerline of the branch channel's return bend is 44-46 mm.

[0029] Preferably, the return bend is semi-circular, and the radius of curvature of the center line of the return bend of the first branch channel 71 and the second branch channel 72 can be selected as 44mm, 44.6mm, 45mm, 45.6mm, and 46mm.

[0030] Furthermore, the diversion angle of the diversion island is 40°~60°.

[0031] Preferably, the split angle can be selected as 40°, 45°, 50°, 55°, or 60°.

[0032] Furthermore, the number of series stages of the Tesla valve units 6 is 1 to 10.

[0033] Preferably, the number of cascaded stages can be selected as 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 stages.

[0034] Preferably, the materials for the sterilization chamber 1 and the Tesla valve unit 6 can be selected from any of polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), or high-density polyethylene (HDPE). The sterilization chamber 1 is a rectangular cavity, and multiple Tesla valve units 6 connected in series are formed inside through micromachining, precision injection molding, or compression molding processes.

[0035] Furthermore, the metal electrodes are made of stainless steel or titanium alloy, preferably titanium alloy. The surface of the metal electrodes is electrolytically polished, which improves the flatness of the surface and reduces the risk of local electric field distortion caused by microscopic protrusions, while also reducing the probability of residual impurities adhering to the sterilization bath solution after sterilization. The two metal electrodes are respectively connected to the positive and negative terminals of the high-voltage pulse power supply, one as the positive metal electrode 4 and the other as the negative metal electrode 5. The positive metal electrode 4 and the negative metal electrode 5 are sealed and fixed to the sterilization chamber 1.

[0036] Specifically, the thickness of the metal electrode is set to 1~3mm, and the thickness of the metal electrode can be selected as 1mm, 2mm, or 3mm. This thickness range can ensure that the metal electrode meets the structural strength requirements and adapts to the fixing and installation requirements of the Tesla valve unit 6, while reducing material costs and avoiding increased manufacturing costs and affecting the uniform distribution of the electric field due to excessively thick metal electrodes.

[0037] Furthermore, the spacing between the two metal electrodes is 15~25mm.

[0038] Preferably, the spacing between the two metal electrodes can be selected as 15mm, 20mm, or 25mm.

[0039] Preferably, the high-voltage pulse electric field generator 9 applies a high-voltage pulse electric field between the two metal electrodes, with a frequency of 10~100Hz, a field strength of 10~40kV / cm, and a pulse width of 1~10μs.

[0040] A method of using a non-thermal sterilization device for sterilizing bath liquid includes the following steps: Connect the first interface 2 to the rotor pump 10, and connect the high-voltage pulse electric field generator 9 to the two metal poles; When used as an infusion pipeline, the rotor pump 10 is controlled to rotate forward, and the liquid flows into the sterilization chamber 1 from the first port 2 and flows out from the second port 3. When sterilization is required, the rotor pump 10 is reversed, and the liquid flows into the sterilization chamber 1 from the second port 3 and flows out from the first port 2. The liquid generates turbulence and bubbles in the Tesla valve unit 6. At the same time, the high-voltage pulse electric field generator 9 is energized to apply a high-voltage pulse electric field between the two metal electrodes, so that the liquid in the sterilization chamber 1 is sterilized by the high-voltage pulse electric field.

[0041] In one specific implementation, the rotor pump 10 is controlled to rotate forward, and the liquid flows into the sterilization chamber 1 from the first interface 2 and flows out from the second interface 3, which is in the flow state. The non-thermal sterilization device is in the forward low-resistance delivery mode. When the liquid enters each Tesla valve unit 6, most of it flows in the shorter flow path inside the diversion island 8 by the diffusion side of the first branch channel 71 and the second branch channel 72 in an ejector manner. Only a very small amount of liquid enters the longer flow path of the arc-shaped flow path outside the diversion island 8. Therefore, the overall flow does not produce significant stagnation, and the Tesla valve unit 6 maintains a laminar flow state with a Reynolds number ≤ 500. In this mode, no high-voltage pulse electric field is applied to the metal electrode, or only a non-bacterial lethal pulse with a frequency of 1Hz~10Hz and a field strength of 0.5kV / cm~1kV / cm is applied, and it is used as a normal infusion pipeline.

[0042] In one specific implementation, the rotor pump 10 is reversed, and liquid flows into the sterilization chamber 1 from the second port 3 and out from the first port 2, i.e., it is in a sterilization state. This non-thermal sterilization device is in a reverse turbulent flow sterilization mode, and the liquid flows in reverse along the Tesla valve unit 6. The liquid flow rate is controlled to keep the Reynolds number between 1000 and 3000 (transitional flow or turbulent flow range). When the liquid enters each Tesla valve unit 6, it is forced to split into the first branch channel 71 and the second branch channel 72, and enters the curved flow path outside the splitting island 8 and the straight flow path inside the splitting island 8 approximately equally at the inlet of the first branch channel. The two parts of the liquid are in place. At the inlet of the secondary branch channel, a collision occurs, inducing turbulence. Turbulent shearing and pressure pulsation cause dissolved gases (air, nitrogen, or carbon dioxide) in the liquid to precipitate and break into microbubbles with diameters of 100 nm to 10 μm, forming a uniformly dispersed gas-liquid two-phase flow. Radial turbulence disrupts the laminar velocity boundary layer, making the residence time distribution more uniform. After the reverse flow stabilizes, a high-voltage pulsed electric field is applied to the two metal electrodes through a high-voltage pulsed electric field generator 9. The parameters are: frequency 10 Hz to 100 Hz, field strength 10 kV / cm to 40 kV / cm, peak voltage 20 to 40 kV, and pulse width 1 μs to 10 μs.

[0043] By setting up a conventional double-plate FEP (control example) and the non-thermal sterilization device of the present invention (example), the sterilization effect under the same total flow channel length, cross-sectional size, electric field strength, and cyclic operating conditions was verified.

[0044] (1) Specimen design The experiment follows the principle of equal hydraulic diameter and equal total length of the flow channel centerline to ensure that the only variable is the flow channel geometry and to eliminate interference from differences in length and cross-section.

[0045] I. Specimen Parameters of the Example The sterilization chamber has a square cross-section and an inner cavity size of 20mm × 20mm (width × height). The diameter of the first and second interfaces is De = 20mm. The sterilization chamber is 120mm long. The inlet and outlet lengths of the diversion island are both 47mm. The radius of curvature of the center line of the semi-circular return bend is 45.6mm. The total length of the reverse flow channel is calculated as follows: inlet and outlet lengths of the diversion island (47+47)mm + upper and lower straight sections (120+120)mm + semi-circular return bend (π×45.6)mm, totaling 477.3mm. II. Parameters of the Equivalent Z-Shaped Straight Pipe Specimen for Comparative Study A square flow channel with a total length of 477.3 mm and a cross-section of 20 mm × 20 mm is adopted. Four 90° elbows with a radius of 45 mm are arranged to form a square shape (185 mm × 185 mm) to match the installation space of the Tesla valve electrode plate. The total arc length of the four elbows is 282.744 mm. The remaining straight section has a total length of 194.556 mm, which consists of two longitudinal sections of 94.9 mm and one transverse section of 4.9 mm straight pipe. (2) Complete sterilization test protocol Pulse power supply: bipolar square wave (suppresses electrochemical reaction), field strength 20kV / cm, peak voltage 40kV, pulse width 2μs, frequency 100Hz, single pulse energy density 40J / mL; Circulation system: Rotary pump (flow rate 600mL / min), 25℃ water bath temperature control, total system volume 200mL; Test solution: Bacterial suspension prepared from Escherichia coli ATCC25922, initial concentration 1.02 × 10⁻⁶ 6 CFU / mL, with conductivity adjusted to 200 μS / cm using sterile phosphate-balanced saline (PBS).

[0046] (3) Sampling and evaluation indicators Sampling points: 0s blank control, 30s, 60s, 120s, 240s; each group of pipes was tested in parallel 3 times; Detection method: Plate count method, serial dilution plating, incubation at 37℃ for 24 hours, counting effective colonies; Core evaluation indicator: Logarithmic inactivation value; the higher the value, the stronger the bactericidal effect. Sterilization improvement rate: The percentage of the difference in logarithmic inactivation between the two groups at 240s relative to the inactivation value of ordinary pipelines.

[0047] (4) Standardized test procedures The process includes equipment disinfection and sealing, preparation of bacterial solution for pre-circulation and mixing, 0s blank sampling, activation of pulsed electric field and timing of rotor pump, aseptic sampling, dilution and plating at each time point, pipeline cleaning after the test, parallel repeated tests, and unified culture and counting.

[0048] The results of the standard test are shown in Table 1.

[0049] Table 1

[0050] At the 240s treatment endpoint, the logarithmic inactivation value of the Tesla valve was 3.40, while that of the conventional straight pipe was 3.00; the sterilization efficiency improvement rate was 13.3%. This result indicates that, under the same equivalent length, cross-section, and electric field conditions, the special structure of the Tesla valve flow channel (bends, flow splitting, and turbulence) enhances fluid mixing and mass transfer, making it easier for the high-voltage pulsed electric field to interact with bacteria at the microbubbles, thus achieving a sterilization efficiency approximately 13% higher than that of the conventional straight pipe at the endpoint.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A non-thermal sterilization device for sterilizing bath liquid, characterized in that, include: The sterilization chamber has a first interface and a second interface at both ends, and the first interface or the second interface can be connected to a rotor pump. The sterilization chamber is composed of several Tesla valve units connected in series. The Tesla valve units are made of insulating and corrosion-resistant materials. Each Tesla valve unit includes two branch channels arranged alternately on the left and right. The first interface corresponds to the converging side of the branch channel, and the second interface corresponds to the diffuser side of the branch channel. Two metal electrodes are connected to the bottom and top surfaces of the sterilization chamber, and the two metal electrodes can be electrically connected to a high-voltage pulse electric field generator. The high-voltage pulse electric field generator is turned off when liquid flows in from the first port and out from the second port. When liquid flows in from the second port and out from the first port, the high-voltage pulse electric field generator is energized to form a high-voltage pulse electric field between the two metal electrodes.

2. The non-thermal sterilization device for sterilizing bath liquid according to claim 1, characterized in that, The cross-section of the branch channel is rectangular, and the width of the branch channel is 15~25mm.

3. The non-thermal sterilization device for sterilizing bath liquid according to claim 1, characterized in that, The inlet or outlet length of the branch channel's diversion island is 40-50 mm, the straight section length of the branch channel is 100-120 mm, and the radius of curvature of the centerline of the branch channel's return bend is 44-46 mm.

4. A non-thermal sterilization device for sterilizing bath liquid according to claim 3, characterized in that, The diversion angle of the diversion island is 40°~60°.

5. A non-thermal sterilization device for sterilizing bath liquid according to claim 1, characterized in that, The number of series stages of some of the Tesla valve units is 1 to 10.

6. A non-thermal sterilization device for sterilizing bath liquid according to claim 1, characterized in that, The metal electrode is made of stainless steel or titanium alloy.

7. A non-thermal sterilization device for sterilizing bath liquid according to claim 1, characterized in that, The surface of the metal electrode sheet is subjected to electrolytic polishing treatment.

8. A non-thermal sterilization device for sterilizing bath liquid according to claim 1, characterized in that, The distance between the two metal electrodes is 15~25mm.

9. A method of using a non-thermal sterilization device for sterilizing bath liquid, characterized in that, Performing the method of use using the non-thermal sterilization device as described in any one of claims 1 to 8 includes the following steps: Connect the first interface to the rotor pump, and connect the high-voltage pulse electric field generator to the two metal poles; When used as an infusion line, the rotor pump is controlled to rotate forward, and the liquid flows into the sterilization chamber from the first port and flows out from the second port. When sterilization is required, the rotor pump is reversed, and the liquid flows into the sterilization chamber from the second port and flows out from the first port. The liquid generates turbulence and bubbles in the Tesla valve unit. At the same time, the high-voltage pulse electric field generator is energized to apply a high-voltage pulse electric field between the two metal electrodes, so that the liquid in the sterilization chamber is sterilized by the high-voltage pulse electric field.

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