Cavitation generator for circulating hydroponics

Abstract

The present invention relates to a cavitation generator for circulating hydroponics, and more specifically, to a cavitation generator for sterilizing drainage, dissolving fertilizer, and supplying dissolved oxygen, wherein the generator induces a cavitation phenomenon by changing the cross-sectional area of ​​an internal flow path to simultaneously achieve sterilization of microorganisms in an aqueous solution, complete dissolution of fertilizer, and dissolution of oxygen, and resupplies the solution to crops being hydroponically cultivated, while eliminating the need for a large storage tank, thereby reducing initial installation and maintenance costs and minimizing environmental pollution. To this end, the present invention relates to a cavitation generator for sterilizing drainage, dissolving fertilizer, and supplying dissolved oxygen in a circulating hydroponic system, wherein The above cavitation generator is applied to a recirculating hydroponic system including a raw water tank, a drainage tank, and one or more nutrient tanks, and The above cavitation generator is, It induces cavitation by forming local low-pressure regions according to changes in the cross-sectional area of ​​the internal flow path, and It is characterized by increasing the amount of dissolved oxygen in the fluid and non-destructively sterilizing harmful bacteria.

Description

Technology Field

[0001] The present invention relates to a cavitation generator for circulating hydroponics, and more specifically, to a cavitation generator for sterilizing drainage water, dissolving fertilizer, and supplying dissolved oxygen, wherein the generator induces a cavitation phenomenon by changing the cross-sectional area of ​​an internal flow path to simultaneously achieve sterilization of microorganisms in the drainage water, complete dissolution of fertilizer, and dissolution of oxygen, and resupplies the solution to crops being hydroponically cultivated, while eliminating the need for a large storage tank, thereby reducing initial installation and maintenance costs and minimizing environmental pollution. Background Technology

[0002] Hydroponics is a technology that cultivates crops using water and nutrient solutions instead of soil. It is widely used as an eco-friendly cultivation method that allows for easy environmental control, reduces pest and disease outbreaks, and minimizes water usage.

[0003] In such hydroponic systems, the hygienic condition of the drainage water that circulates for a long period serves as a very important management factor. In general hydroponics, excess drainage water that is not absorbed by the plant roots is discharged, and this drainage water contains large amounts of plant secretions, suspended organic matter, fungal spores, and pathogenic bacteria.

[0004] If such drainage is reused without purification, it leads to crop growth disorders and the spread of pathogens; to prevent this, methods such as UV sterilizers, ozone sterilizers, and chlorine injection are being used.

[0005] However, these methods have the following problems.

[0006] First, UV sterilizers have the problem that their sterilization effect is significantly reduced in turbid drainage with low transmittance, and operating costs increase due to the short lamp life and high energy consumption.

[0007] In addition, while ozone or chlorine injection methods provide powerful sterilization through chemical oxidation, residual oxidizers can damage crop roots, and the need for continuous maintenance of the gas injection device leads to reduced drainage recycling efficiency and increased operating costs.

[0008] Meanwhile, most fertilizers for hydroponics are in the form of crystalline inorganic salts, and incomplete dissolution leads to problems such as nozzle clogging, concentration variations, and the formation of precipitates inside the nutrient solution system. Conventionally, agitators or circulation pumps were used to promote dissolution, but mechanical stirring alone made it difficult to completely dissolve fine crystals, resulting in the problem of residues remaining.

[0009] In addition, there is a problem with dissolved oxygen (DO) deficiency. Since crop root respiration is significantly affected by dissolved oxygen concentration, if the concentration of dissolved oxygen drops below 4 mg / L, root decay, redox imbalance, and reduced growth occur. Furthermore, with conventional air injection methods, oxygen is rapidly lost, making it difficult to maintain a constant concentration.

[0010] Furthermore, conventional rotary mixers or stirred cavitation devices have high failure rates during long-term operation due to wear and vibration of the rotating parts, and frequently suffer from corrosion and damage caused by changes in the pH or salt concentration of the culture medium. Prior art literature

[0011] Republic of Korea Registered Patent No. 10-2811677 (Registered May 19, 2025) Republic of Korea Registered Patent No. 10-2671987 (Registered May 30, 2024) Republic of Korea Registered Patent No. 10-1370229 (Registered February 26, 2014) The problem to be solved

[0012] The present invention is proposed to solve the above-mentioned problems and aims to provide a circulating hydroponic cavitation generator that improves the efficiency and stability of a hydroponic system by realizing the recycling of drainage, complete dissolution of fertilizer, and increase of dissolved oxygen in a single integrated cavitation system.

[0014] In particular, the present invention aims to provide a circulating hydroponic cavitation generator that non-destructively removes harmful bacteria in drainage by realizing physical and chemical sterilization using the cavitation phenomenon, facilitates maintenance with a non-rotating structure, and improves fertilizer dissolution efficiency by generating powerful microcavities through changes in the cross-sectional area of ​​the flow path.

[0016] In addition, the purpose is to provide a circulating hydroponic cavitation generator that optimizes the crop growth environment by increasing dissolved oxygen concentration through the injection of air, oxygen, and ozone gases. means of solving the problem

[0017] To achieve the above objective, the present invention relates to a cavitation generator for sterilizing drainage water, dissolving fertilizer, and supplying dissolved oxygen in a recirculating hydroponic system, wherein

[0018] The above cavitation generator is applied to a recirculating hydroponic system including a raw water tank, a drainage tank, and one or more nutrient tanks, and

[0019] The above cavitation generator is,

[0020] It induces cavitation by forming local low-pressure regions according to changes in the cross-sectional area of ​​the internal flow path, and

[0021] It is characterized by increasing the amount of dissolved oxygen in the fluid and non-destructively sterilizing harmful bacteria.

[0023] In addition, the mixed water supplied from the raw water tank and the drainage tank is circulated through a plurality of pumps by an electronic control module, and the circulation and dissolution process of the nutrient solution tank is automatically controlled by a water level sensor and a plurality of solenoid valves provided in the nutrient solution tank.

[0025] In addition, the cavitation generator is characterized by injecting at least one gas among air, oxygen, or ozone to improve the dissolved oxygen concentration and increase the sterilization efficiency.

[0027] At this time, the cavitation generator is characterized by comprising: a body having a moving space formed inside for the movement of drainage and an inlet and an outlet formed at each end in the longitudinal direction for the inflow of drainage; a cavitation forming means installed on the body to cause the moving drainage to collide and generate a cavitation phenomenon; and a stopper ring for fixing the cavitation forming means to the body.

[0029] In addition, the cavitation forming means is characterized by including an inlet plate installed at the inlet and having an inlet hole formed in the center for the inflow of drainage, and a collision plate installed at the outlet and having a collision portion provided for a portion of the drainage that has moved through the movement space to collide.

[0031] In addition, the cavitation forming means comprises a plurality of venturi forming plates arranged in close contact with each other, with a moving hole formed in the center through which drainage moves, a support member arranged in the moving space through which a portion of the drainage passing through the moving hole collides, and a support plate having a discharge hole through which drainage moves.

[0033] At this time, the Venturi forming plate is characterized in that the moving holes are formed to have different diameters, and the moving holes are arranged to form a Venturi shape for the path through which the drainage moves in the moving space. Effects of the invention

[0034] The present invention, as described above, utilizes a non-rotating cavitation generator to simultaneously perform drainage sterilization, fertilizer dissolution, and dissolved oxygen increase in a single process. Furthermore, since it eliminates the need for a storage tank for sterilizing conventional circulating nutrient solution or drainage, it has the effect of reducing initial installation and operating costs and minimizing the installation area.

[0036] The present invention has the effect of enabling non-contact, non-chemical sterilization, as microcavities generated by the cavitation phenomenon collapse instantaneously at 10,000 K (Kelvin) and 1,000 atmospheres or more, and as water molecules decompose, hydroxyl radicals and reactive oxygen species are generated, thereby damaging the cell membrane and DNA of bacteria and sterilizing without using chemical agents.

[0037] In particular, phytopathogens, fungal spores, and bacteria in the drainage are effectively removed, enabling the recycling of the culture medium.

[0039] In addition, the present invention has the effect of significantly improving the root growth and nutrient absorption efficiency of crops by allowing the gas introduced from the collision plate to collide, crush, and disperse the gas along with the collapse of cavitation bubbles, thereby maintaining a high dissolved oxygen concentration.

[0041] In addition, since the present invention generates cavitation through a cavitation forming means, there is no wear on rotating parts such as motors and impellers, vibration and noise are minimized, and maintenance costs are significantly reduced due to easy disassembly, cleaning, and replacement.

[0043] In addition, the present invention can reduce wastewater generation by recycling sterilized drainage water and significantly reduce the amount of raw water used. Furthermore, it enables reduced operating costs and improved safety, and improves the stability and homogeneity of the culture solution, thereby improving the growth speed and quality of crops. Brief explanation of the drawing

[0044] FIG. 1 is an exemplary diagram illustrating a hydroponic system to which a cavitation generator for circulating hydroponic cultivation according to the present invention is applied. FIG. 2 is an exemplary diagram illustrating a cavitation generator constituting the present invention. FIG. 3 is an exploded view of the cavitation generator illustrated in FIG. 2. FIG. 4 is an illustrative diagram showing one embodiment of a cavitation forming means constituting the present invention. FIG. 5 is an illustrative diagram showing another embodiment of the inlet plate and impact plate constituting the present invention. FIG. 6 is an exemplary diagram illustrating another embodiment of the cavitation forming means constituting the present invention, showing a state separated from the body. FIG. 7 is a cross-sectional view illustrating the cross-section of the Venturi forming plate of FIG. 6. Specific details for implementing the invention

[0045] In addition to the above objectives, other objectives and features of the present invention will become apparent through the description of embodiments with reference to the accompanying drawings.

[0047] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this application.

[0049] Hereinafter, a preferred embodiment of a cavitation generator for circulating hydroponic cultivation according to the present invention will be examined in detail with reference to the attached drawings.

[0051] First, the cavitation generator (50) for circulating hydroponic cultivation according to the present invention is a cavitation generator for sterilizing drainage water, dissolving fertilizer, and supplying dissolved oxygen in a circulating hydroponic cultivation system. The cavitation generator (50) is applied to a circulating hydroponic cultivation system comprising a raw water tank (10), a drainage tank (20), and one or more nutrient tanks (60) (70). The cavitation generator (50) induces cavitation by forming a local low-pressure region according to a change in the cross-sectional area of ​​an internal flow path, thereby increasing the amount of dissolved oxygen in the fluid and non-destructively sterilizing harmful bacteria.

[0053] To this end, the present invention circulates the mixed water supplied from the raw water tank and the drainage tank through a plurality of pumps (P1)(P2) by an electronic control module, and the circulation dissolution process of the nutrient tank (60)(70) is automatically controlled by a water level sensor (L3)(L4) and a plurality of solenoid valves (S0~S14) provided in the nutrient tank (60)(70).

[0054] FIG. 1 illustrates a circulating hydroponic system using a cavitation generator (50) for circulating hydroponic cultivation according to the present invention, wherein a raw water tank (10) and a drainage tank (20) are each provided, and the system includes a nutrient tank A (60), a nutrient tank B (70), a hydrogen peroxide tank (30), a pressure vessel (40), a cavitation generator (50), pumps (P1) (P2), a plurality of solenoid valves (S0~S14), a plurality of water level sensors (L1~L4), and circulation line detection sensors (SM1) (SM2).

[0055] Looking at the operation state of this system, it is structured to mix raw water and drainage water for recirculation, and water is supplied from the raw water tank (10) through a pump (P1), and the pre-sterilization drainage from the drainage tank (20) is combined.

[0056] Afterward, sterilization and oxygen dissolution are performed while passing through a cavitation generator (50), and after sterilization, it is transferred to a drainage tank (20) and supplied to a nutrient solution generator and a nutrient solution tank.

[0057] The mixing and fertilizer dissolution process of nutrient tank A (60) and nutrient tank B (70) is performed, and a constant pressure is maintained through the pressure vessel (40).

[0058] Air, oxygen, and ozone gas are injected from the top of the cavitation channel to adjust the oxidizing power and the concentration of dissolved oxygen.

[0059] This series of flows is automatically executed by the electronic control module (PLC) through sequence control of valves and pumps.

[0061] Looking at an example of a drainage sterilization process carried out through the above electronic control module (PLC), it starts by opening valves S1 and S3.

[0062] The sterilization preparation process involves preparing for sterilization by applying a sterilization dilution ratio, and the second pump (P2) is operated while the first pump (P1) is operated. This involves operating the second pump (P2) by an amount equal to the sterilization dilution ratio of the drainage water before sterilization to mix hydrogen peroxide (H2O2) with the drainage water before sterilization.

[0063] Subsequently, in the self-circulation process of drainage, when the water level of the drainage tank (20) before sterilization reaches the upper limit, valve S1 is closed and valve S2 is opened.

[0064] Subsequently, the sterilization process proceeds as the mixed liquid stored in the pre-sterilization drainage tank (20) passes through cavitation, and at this time, valve S2 is OPEN, valve S3 is Closed, valve S4 is Open, and valve S5 is Open.

[0065] During the process, when the water level of the drainage tank (20) before sterilization reaches the lower limit and the drainage tank (21) after sterilization reaches the upper limit, all valves are closed.

[0067] Next, looking at an example of the fertilizer dissolution process, the fertilizers for Nutrient Solution A and Nutrient Solution B are manually added, and valves S0 and S6 are opened, respectively.

[0068] Next, the first pump (P1) for supplying the nutrient solution is operated, and in the fertilizer self-dissolution process, when the nutrient solution tank A (60) reaches the upper limit, valve S6 is closed and valve S7 is opened simultaneously. At this time, valves S6 to S9 are connected to the bottom of nutrient solution tank A (60) and nutrient solution tank B (70).

[0069] Afterwards, when the nutrient tank B (70) reaches the upper limit, the nutrient tank A (60) waits and at this time, valve S7 is closed.

[0070] In the next fertilizer circulation dissolution process, the fertilizer SM circulation dissolution A nutrient solution tank B (70) is in standby mode, and valves S6 and S8 are opened. The nutrient solution discharged from nutrient solution tank A (60) is dissolved in a mixture of raw water and drainage solution, and during the dissolution process, the operating status is detected through the first circulation line detection sensor (SM1).

[0071] B. For the fertilizer SM circulation dissolution, the nutrient solution tank A (60) is in standby mode, valves S6 and S8 are closed respectively, and valves S7 and S9 are opened respectively, so that the nutrient solution discharged into the nutrient solution tank B (70) is dissolved, and during the dissolution process, the operating state is detected through the first circulation line detection sensor (SM1).

[0072] Next, regarding the cavitation circulation process of the fertilizer, valves S7 and S9 are closed, and valves S4, S8, and S10 are opened so that the nutrient solution discharged from nutrient tank A (60) passes through the cavitation generator (50) and the fertilizer is dissolved. For the circulation dissolution of the nutrient solution discharged from nutrient tank B (70), while nutrient tank A (60) is in standby mode, valves S8 and S10 are closed, and valves S9 and S11 are opened so that the nutrient solution discharged from nutrient tank B (70) passes through the cavitation generator (50) and the fertilizer is dissolved, and the operating state, concentration, fertilizer dissolution state, etc. are detected through the second circulation line detection sensor (SM2).

[0074] A process for increasing dissolved oxygen is, for example, a method of directly introducing air into a cavitation generator (50), wherein valve S12 is opened and valves S13 and S14 are closed respectively.

[0075] Also, as another example, in the method of supplying air to the pump, valve S12 is closed, and valves S13 and S14 are each opened.

[0077] Next, we will examine in detail the cavitation generator (50), which is a characteristic component of the present invention.

[0078] A cavitation generator (50) according to the present invention comprises a body (51) having a moving space (511) formed therein for moving drainage, and an inlet (512) and an outlet (513) formed at each end in the longitudinal direction for the drainage to flow in, a cavitation forming means (52) installed in the body (51) to cause a cavitation phenomenon by colliding with the moving drainage, and a stopper ring (53) for fixing the cavitation forming means (52) to the body (51).

[0080] The above body (51) has a predetermined length and is hollow inside, with both ends in the longitudinal direction open to allow drainage to move. A movement space (511) for the movement of drainage is formed inside, an inlet (512) for the inflow of drainage is formed at one end in the longitudinal direction, and an outlet (513) for the discharge of drainage is formed at the other end in the longitudinal direction.

[0081] In the present invention, the body (51) is such that the drainage (drainage or circulating water) used in hydroponic cultivation flows in at one end and is discharged at the other end, and a cavitation forming means (52) described later is provided in the moving space (511) formed between the inlet (512) and the outlet (513) so that cavitation occurs.

[0082] This body (51) is generally made of a cylindrical or polygonal tubular body and is configured to be connected to an external circulation line so that drainage can flow continuously.

[0083] In addition, the body (51) is formed of a corrosion-resistant metal (e.g., stainless steel) or a high-strength synthetic resin (e.g., POM, PVDF, PPS, etc.) and is manufactured to withstand micro-impact pressure caused by cavitation and corrosion caused by bubble collapse.

[0084] In addition, the interior of the body (51) is processed to have a smooth surface to facilitate cavitation, and ribs for turbulence formation or grooves for pressure relief may be formed as needed.

[0085] Meanwhile, at each end of the body (51) in the longitudinal direction, a coupling flange (514) extending outwardly is formed to be coupled with an external circulation line, and each coupling flange (514) is formed with an inwardly recessed mounting groove (516) in which a sealing packing (not shown) is seated to maintain airtightness between the coupling and the external circulation line.

[0086] Meanwhile, the diameter and length of the body (51) are formed to have a diameter corresponding to the external circulation line for connection with the external circulation line, and the length can be determined according to the placement position of the cavitation forming means (52) placed in the movement space (511), and is not limited to the embodiments shown in the drawings.

[0088] The above cavitation forming means (52) is a core component of the present invention and is positioned in the moving space (511) inside the body (51) to cause a cavitation phenomenon by colliding with or inducing a change in speed of the moving drainage.

[0090] [Example 1]

[0091] As an example of such a cavitation forming means (52), it includes an inlet plate (521) disposed at the inlet (512) of the body (51) and a collision plate (522) disposed at the outlet (513).

[0092] The above-mentioned inlet plate (521) is installed on the side of the inlet port (512) and has an inlet hole (521a) formed in the central part through which drainage passes. As the incoming drainage passes through this inlet hole (521a), its speed is accelerated and turbulence is formed on the rear surface of the inlet plate (521). That is, the inlet hole (521a) is formed to have a relatively small diameter compared to the inner diameter of the movement space (511). As the drainage moving through the movement space (511), or more precisely through the external circulation line, passes through the inlet hole (521a) with a small diameter, its speed is accelerated, and after passing through the inlet hole (521a), it moves into the movement space (511) with an expanded area and forms turbulence.

[0093] The above collision plate (522) is positioned on the discharge port (513) side, and a collision part (522a) is formed in the central part where the discharged fluid moving through the movement space (511) directly collides.

[0094] Here, the collision portion (522a) may be formed as a flat disc-shaped portion, a convex hemispherical or conical shape.

[0095] The edge of the collision plate (522) and the central collision part (522a) are joined by a plurality of connecting ribs (522b) so that some of the drainage fluid escapes into the space formed between the connecting ribs (522b), thereby causing the collapse of bubbles caused by collision to occur intensively.

[0096] In the space between the inlet plate (521) and the impact plate (522) configured in this way, a change in flow velocity and a drop in pressure occur simultaneously, causing a number of cavitation bubbles to be generated and collapse, and accordingly, OH radicals are formed, thereby sterilizing action is achieved.

[0097] At this time, the distance between the inlet plate (521) and the collision plate (522) has a direct effect on the generation efficiency of cavitation bubbles, and their distance is controlled through the following Equation 1.

[0099] [Formula 1]

[0100] Q = A·V

[0101] t = V = L / t, L = V·t

[0103] Q is the flow rate, L is the distance to the collision plate, and t is time.

[0105] Equation 1 above represents the basic continuity equation and the time-distance relationship of fluid flow together, where Q=A·V, Q is the flow rate (m³ / s), which is the volume of fluid passing per unit time, A is the cross-sectional area (m²), and V is the flow velocity (m / s).

[0106] In other words, the instantaneous flow rate when a fluid passes through a passage with cross-sectional area A is proportional to the flow velocity V; as A narrows, V increases, and as A widens, V decreases.

[0107] This principle also applies to Example 2 described below.

[0109] And, in L = V·t, L is the distance the fluid travels (e.g., the distance from the inlet plate to the impact plate), V is the average velocity of the fluid, and t is the time it takes for the fluid to travel that distance. This is a basic kinematic relationship, representing velocity * time = distance.

[0111] The cavitation generator (50) of the present invention causes cavitation to occur due to a pressure difference before reaching the collision plate as the drainage moves in the order of the inlet plate (521), the moving space (511), and the collision plate (522), and in this case, the above Equation 1 has the following meaning.

[0113] sign meaning explanation Q Flow rate (㎥ / s) The amount of water supplied by a pump or circulation device A Cross-sectional area of ​​the movement space Varies depending on the diameter of the movement space or the Venturi section V Flow velocity (m / s) It increases as the cross-sectional area A narrows. L Distance between the inlet plate and the impact plate Cavitation bubble collapse location t Time for the fluid to move L Cavitation bubble collapse time

[0115] Q = A·V. As the cross-sectional area A decreases rapidly, V (velocity) increases; due to this increase in velocity, the static pressure decreases, and at this time, a portion of the fluid vaporizes, forming cavitation bubbles.

[0116] In the present invention, the correlation between Q, A, V, L, and t is optimized to maximize the amount of OH radicals generated at the point where cavitation occurs most actively.

[0118] To summarize Equation 1 above, Q = A·V is the product of cross-sectional area and flow velocity, which is a constant flow rate, and induces an increase in flow velocity by reducing the cross-sectional area in the moving space or Venturi section, L = V·t is the relationship between velocity, time, and distance, which adjusts the cavitation maintenance time and sterilization efficiency, and V=L / t is the velocity determination equation, which controls the bubble generation intensity according to the fluid's movement speed.

[0120] By using this formula 1, the inlet hole (521a) or the moving hole of Example 2 described later forms a region where the static pressure decreases as the flow velocity increases rapidly according to the diameter, thereby inducing localized cavitation to occur, and by appropriately adjusting the distance (L) and flow velocity (V) from the inlet hole (521a) to the impact plate (522) so that the bubble collapses at the optimal location, the amount of OH radicals generated can be maximized.

[0122] Fine bubbles formed by cavitation temporarily create high temperature and high pressure conditions upon collapse, and during this process, water molecules decompose to generate OH radicals.

[0123] The generated OH radicals have high oxidizing power, so they can oxidize and decompose not only microorganisms such as bacteria, fungi, and algae present in the drainage but also organic pollutants.

[0125] Meanwhile, in the present invention, the inlet hole (521a) may be formed as one or more at intervals, and the collision part (522a) may be connected to the edge of the collision plate (522) by a plurality of connecting ribs (522b), and may be formed as one or more at intervals.

[0126] This involves adjusting the number of inlet holes (521a) and impact plates (522) to control the flow rate of the drainage or the cavitation generation efficiency, and it goes without saying that various variations are possible in addition to the form shown in the drawing.

[0128] Looking at the operation of Example 1 above, the discharge discharged from the circulation pump of the hydroponic system is rapidly accelerated as it passes through the inlet hole (521a) of the inlet plate (521), and at this time, as the pressure decreases, a number of cavitation bubbles are formed. The formed bubbles collide with the impact plate (522) on the downstream side and collapse, and upon collapse, approximately 10,000 K (Kelvin) and 1,000 atmospheres of pressure are generated locally, and as a result, water (H₂O) is decomposed and the following reaction occurs.

[0129] H2O→·OH+·H

[0130] The generated OH radicals oxidize and decompose the protein bonds of the bacterial cell walls, inactivating most bacteria.

[0132] [Example 2]

[0133] As another embodiment of the cavitation forming means (52) of the present invention, a plurality of venturi forming plates (523) are arranged in close contact with each other and are disposed in the moving space (511), with a moving hole (523a) formed in the center through which drainage moves, a support member (524a) disposed in the moving space (511) through which a portion of the drainage passing through the moving hole (523a) collides, and a support plate (524) having a discharge hole (524b) through which drainage moves formed.

[0135] The above-mentioned venturi forming plate (523) is a thin, disc-shaped plate, and a passage hole (523a) through which drainage passes is formed in the center. A plurality of venturi forming plates (523) are arranged in close stacking, and the diameters of the passage holes (523a) of each plate are formed differently from one another so that the flow velocity accelerates and then decelerates as the fluid moves.

[0136] As a result, a sudden drop in pressure occurs in the section passing through the moving hole (523a), and a large amount of cavitation bubbles are formed.

[0137] Meanwhile, the above-mentioned venturi forming plate (523) is arranged so that the path through which the drainage moves is formed in the shape of a venturi, with a moving hole (523a) formed in the center.

[0138] Here, the Venturi shape is a conical tube form in which the middle of the fluid flow path narrows and then widens again; this Venturi shape generates the Venturi effect, which increases velocity and simultaneously reduces pressure.

[0139] In the present invention, the arrangement position and number of the venturi forming plates (523) are adjusted so that the moving holes (523a) formed in the continuously arranged venturi forming plates (523) are formed in a venturi shape, thereby controlling the flow velocity and pressure as the drainage introduced through the inlet (512) passes through the moving holes (523a) arranged in a venturi shape.

[0140] The support plate (524) is positioned in the moving space (511) and has a support portion (524a) that collides with a portion of the drainage fluid passing through the moving hole (523a) and a discharge hole (524b) through which the drainage fluid moves.

[0141] The above support member (524a) may be formed in the shape of a flat plate and may be formed in the shape of a hemispherical or wedge that protrudes convexly outward.

[0143] The cavitation forming means (52) formed as described above has no separate rotating part inside, so it has low noise and can continuously generate stable cavitation even in a low-pressure environment.

[0144] In addition, by adjusting the placement position and number of the above-mentioned venturi forming plates (523) according to the flow rate and pressure of the drainage, and by adjusting the placement position and number of the venturi forming plates (523) according to the diameter of the moving hole (523a) formed in the venturi forming plates (523) to form a venturi-shaped space for the drainage to move, the movement speed of the drainage can be stably controlled even at low pressure, thereby increasing the cavitation generation efficiency.

[0145] At this time, the spacing between the Venturi forming plate (523) and the support plate (524), and the diameter of the Venturi shape formed by the moving hole (523a) of the Venturi forming plate (523) are set according to the aforementioned Equation 1.

[0147] Looking at the operation state of Example 2 above, as the drainage passes through the moving hole (523a), the speed increases, the pressure drops, and cavitation occurs. Subsequently, as it hits the support portion (524a) of the support plate (524), the bubbles collapse intensively, and the density of OH radical generation is improved compared to the inlet portion.

[0148] Fine bubbles formed by cavitation temporarily create high temperature and high pressure conditions upon collapse, and in this process, water molecules are decomposed to generate OH radicals. Since the generated radicals have high oxidizing power, they can oxidize and decompose not only microorganisms such as bacteria, fungi, and algae present in the drainage but also organic pollutants.

[0150] Accordingly, the cavitation forming means (52) according to the present invention has the effect of improving the hygiene level of the circulating drainage, preventing contamination of the piping system, and reducing the maintenance costs of the entire hydroponic system.

[0151] In addition, by adjusting the number and diameter differences of the Venturi forming plates, flow velocity and cavitation intensity can be finely controlled, and it provides the flexibility to optimize sterilization efficiency according to crop type or culture environment.

[0152] In other words, the present invention has the technical effect of securing stable and continuous sterilization performance by providing an optimal design structure based on the interrelationships of hydrodynamic parameters (Q, A, V, L, t), rather than simply sterilization using cavitation.

[0154] The above stopper ring (53) is for firmly fixing the cavitation forming means (52) to the body (51), and is made of a metal or heat-resistant resin material and can be joined by screw fastening, clip fixing, or O-ring compression.

[0155] These stopper rings (53) prevent internal parts from coming off due to vibration during use, or the inlet plate, impact plate, venturi forming plate, and support plate from being deformed or having their spacing changed.

[0157] Meanwhile, the material of the cavitation forming means (52) described above can be varied such as titanium, stainless steel, polycarbonate, etc., and the shape of the inlet hole and the collision part can be modified into a circular, polygonal, or star shape.

[0158] In addition, by forming a spiral flow path on the inner surface of the body to induce bubble rotational flow, the residence time of OH radicals can be increased.

[0160] [Example 3]

[0161] Next, Example 3 is an example in which an Advanced Oxidation Process (AOP) is performed by combining cavitation phenomena with hydrogen peroxide (H2O2) to generate a strong oxidizing radical.

[0162] Hydrogen peroxide has a slow decomposition reaction, but it decomposes rapidly in high temperature, high pressure, and shock wave environments caused by cavitation, generating large amounts of OH radicals and oxygen.

[0163] The major factors affecting the decomposition rate of hydrogen peroxide include the presence or absence of a catalyst, temperature, concentration, and pH.

[0164] When a catalyst (manganese dioxide, catalase, metal ions, etc.) is present, the decomposition time is shortened to within a few minutes, the reaction rate is accelerated as the temperature increases, and the reaction is accelerated under specific pH conditions (e.g., acidic conditions in the case of Fe catalyst) as the concentration of hydrogen peroxide and catalyst increases.

[0165] In a sterilization process combining hydrogen peroxide and cavitation, cavitation bubbles generate OH radicals through physical sterilization and the decomposition of water molecules via high temperature / high pressure and shear force generated upon bubble collapse in the liquid, and hydrogen peroxide acts as a major reactant for the generation of OH radicals as a powerful oxidizing agent, and OH radicals provide very strong oxidizing power, thereby having a decomposition and sterilization effect on pathogens and organic contaminants.

[0166] Meanwhile, the drainage contains iron (Fe) remaining during crop growth 2+ ), copper (Cu 2+ ), manganese (Mn 2+ It contains metal ions such as ), and these metal ions act as catalysts for Fenton or Fenton-like reactions to react with hydrogen peroxide to generate additional OH radicals.

[0168] Fe 2+ + H2O2-> Fe 3+ + ·OH + OH -

[0170] Additionally, the oxygen (O2) generated by the incidentally accelerated H2O2 decomposition reaction (2H2O2 → 2H2O + O2) increases the dissolved oxygen (DO) concentration in the drainage, contributing to plant root health.

[0171] Here, strong OH radicals generated during the Fenton oxidation reaction partially destroy the bonds of chelating agents (EDTA-Fe, DTPA-Fe) surrounding iron to maintain plant absorption and solubility, thereby degrading the chelating agents and reducing the concentration of chelated iron ions, which are the effective form of iron available to plants.

[0172] Therefore, after sterilization treatment, the concentration of chelated iron in the drainage must be measured, and any deficiency must be supplemented to maintain the nutrient levels necessary for plant growth.

[0173] To this end, after sterilization treatment, the chelated iron concentration in the drainage is measured, and if insufficient, powdered chelated iron (EDTA-Fe) or liquid chelated iron (DTPA-Fe) is replenished.

[0175] As described above, the present invention has been explained by specific details such as specific components, limited embodiments, and drawings; however, this is provided merely to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments. A person skilled in the art can make various modifications and variations from this description.

[0177] Accordingly, the scope of the present invention should not be limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention. Explanation of the symbols

[0179] 1 : Cavitation generator for circulating hydroponics 10 : Raw water tank 20 : Drainage tank 21 : Drainage tank after sterilization 30: Hydrogen peroxide tank 40 : Pressure tank 50 : Cavitation generator 51: Body 52: Cavitation forming means 53 : Stoppering 511 : Movement space 512 : Inlet 513 : Outlet 514 : Flange 515 : Spare 516 : Seating groove 521 : Inlet plate 521a : Inlet port 522: Collision plate 522a: Collision part 522b : Connecting line 523: Venturi forming plate 523a : Mobile gun 524 : Support plate 524a : Support part 524b : Discharge port 60 : Nutrient tank A 70 : Nutrient Tank B

Claims

Claim 1 In a cavitation generator for sterilizing drainage, dissolving fertilizer, and supplying dissolved oxygen in a recirculating hydroponic system, the cavitation generator (50) is applied to a recirculating hydroponic system including a raw water tank (10), a drainage tank (20), and one or more nutrient tanks (60), (70). The cavitation generator (50) induces cavitation by forming a local low-pressure region according to a change in the cross-sectional area of ​​an internal flow path, thereby increasing the amount of dissolved oxygen in the fluid and sterilizing harmful bacteria. The cavitation generator (50) injects at least one gas among air, oxygen, or ozone to improve the dissolved oxygen concentration and increase the sterilization efficiency. The cavitation generator (50) comprises a body (51) having a movement space (511) formed inside for the movement of drainage, and an inlet (512) and an outlet (513) formed at each end in the longitudinal direction for the inflow of drainage, respectively. The apparatus includes a cavitation forming means (52) installed in a body (51) to cause a cavitation phenomenon by colliding with a moving drain, and a stopper ring (53) for fixing the cavitation forming means (52) to the body (51). The cavitation forming means (52) comprises a plurality of venturi forming plates (523) arranged in close contact with each other, which are positioned in the moving space (511) and have a moving hole (523a) formed in the center through which the drain moves, a support member (524a) which is positioned in the moving space (511) through which a portion of the drain passing through the moving hole (523a) collides, and a support plate (524) which has a discharge hole (524b) through which the drain moves formed. The venturi forming plates (523) are formed such that the moving holes (523a) have different diameters, and the path through which the drain moves in the moving space (511) is a venturi A cavitation generator for circulating hydroponics characterized by being arranged to form a shape. Claim 2 A circulating hydroponic cavitation generator according to claim 1, wherein the mixed water supplied from the raw water tank and the drainage tank is circulated through a plurality of pumps (P1) and (P2) by an electronic control module, and the circulation dissolution process of the nutrient tanks (60) and (70) is automatically controlled by water level sensors (L3) and (L4) and a plurality of solenoid valves (S0 to S14) provided in the nutrient tanks (60) and (70), respectively. Claim 3 delete Claim 4 delete Claim 5 A circulating hydroponic cavitation generator according to claim 1, wherein the cavitation forming means (52) comprises an inlet plate (521) installed at the inlet (512) and having an inlet hole (521a) formed in the center for the inflow of drainage, and a collision plate (522) installed at the outlet (513) and having a collision part (522a) on which a portion of the drainage that has moved through the movement space (511) collides. Claim 6 delete Claim 7 delete

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