Multi-port Venturi fertilization and oxygenation device

Abstract

A multi-port Venturi fertilization and oxygenation device comprises a liquid inlet section, a contraction section, a throat pipe section, an expansion section and an outlet section which are sequentially connected in the liquid flowing direction, and liquid is shunted in the contraction section, passes through at least two symmetrical sub contraction sections, at least two sub throat pipe sections and at least two sub expansion sections and then converges in the expansion section; the sub venturi devices are symmetrical; the suction section is communicated with the throat pipe and sucks fertilizer or air under the action of pressure, and water fertilizer, water vapor or water fertilizer and gas are mixed through the throat pipe section and the expansion section, so that the mixed fertilizer or irrigation water oxygenation is realized. According to the Venturi fertilization and oxygenation device provided by the invention, the head loss is effectively reduced, and the mixing efficiency of irrigation water and fertilizer or air is improved.

Description

Technical Field

[0001] The invention belongs to the field of agricultural irrigation technology equipment, and in particular relates to a multi-venturi fertilization and oxygenation device. Background Art

[0002] The precise provision of crop irrigation and fertilization is the basis for ensuring a steady increase in grain production. It provides various minerals and water required for plant growth, and has an important impact on soil structure changes, heat transfer, and soil microbial reproduction. With the continuous advancement of water-fertilizer-gas integration technology, research on water-fertilizer-gas mixing equipment has received increasing attention. The Venturi device has been widely used in agricultural production due to its simple structure, no moving parts, low failure rate, convenient operation, and labor saving. The Venturi device not only effectively improves the mixing and utilization efficiency of water, fertilizer, and gas, but also promotes the balanced growth of crops, significantly improving the economic benefits and sustainability of agricultural production.

[0003] At present, Venturi tube microbubble generators can be divided into three categories: conventional Venturi tube microbubble generators, jet Venturi tube microbubble generators and special-shaped Venturi tube microbubble generators. There are two main methods for collecting soil leachate. The main body of the conventional Venturi tube microbubble generator is composed of a Venturi flow channel and an injection pipe, wherein the Venturi flow channel is composed of a contraction section, a throat section and an expansion section, and the injection hole tube is opened at the throat position. The working principle of the jet microbubble generator is similar to that of the gas-liquid jet pump. The core is a Venturi-like structure, which is specifically composed of four parts: a nozzle, an air suction chamber, a throat, and a diffuser. The main structure of the deformed Venturi tube is a special-shaped Venturi tube by adding small balls and baffles in the main channel.

[0004] The Chinese invention (CN113439514A) discloses a Venturi fertilizer applicator and a fertilizer application device, including: a contraction section, a throat section, a diffusion section and a fertilizer suction section. The contraction section is connected to the diffusion section through the throat section, and the fertilizer suction section is connected to the throat section. The diameter of the liquid inlet of the contraction section is larger than the diameter of its liquid outlet, and its longitudinal section is a right-angled trapezoid; the diameter of the liquid inlet of the diffusion section is smaller than the diameter of its liquid outlet, and its longitudinal section is an eccentric curved quadrilateral, in which three angles are right angles and one angle is an acute angle. Since the right-angled side where the height of the right-angled trapezoid is located is on the same horizontal line as the right-angled side where the height of the eccentric curved quadrilateral is located, multi-directional velocity collisions are reduced, which can effectively reduce head losses.

[0005] The Chinese invention (CN110419310A) discloses a low-pressure irrigation double fertilizer suction port Venturi fertilizer applicator, including a water inlet section, an axisymmetric contraction section, a throat section, an axisymmetric expansion section and a water outlet section. The water inlet section, the axisymmetric contraction section, the throat section, the axisymmetric expansion section and the water outlet section are arranged in sequence along the water flow direction. The throat section is symmetrically provided with two fertilizer suction pipes, which changes the water flow state of the classic Venturi fertilizer suction device, makes the negative pressure area in the throat more evenly distributed, and the fertilizer liquid flow direction and the water flow direction can be mixed more quickly, which is conducive to stabilizing fertilizer absorption and improving the fertilizer absorption ratio. The fertilizer suction pipe in the throat evenly distributes the negative pressure area formed by the sudden contraction of the throat section on the annular section where the entire fertilizer suction pipe and the throat section are connected, making the negative pressure area more stable and concentrated, and further reducing the working pressure at the front end of the Venturi tube.

[0006] The Chinese invention (CN111450719A) discloses a composite Venturi-type microbubble generating device, including a primary Venturi channel and a secondary Venturi channel. After the bubbles are initially broken in the cyclone zone of the primary Venturi channel, they enter the cyclone zone of the secondary Venturi channel for further breaking. The device does not require external auxiliary power facilities, and utilizes the kinetic energy of the liquid in the Venturi channel to produce a large number of microbubbles with a diameter of about 100 microns through the secondary cyclone zone of the secondary Venturi channel at low energy consumption, which has the advantage of low operating cost.

[0007] The Chinese invention (CN115487955A) discloses a microbubble water generating device, including a main body and a spiral body. The main body has a water inlet channel, a water-gas mixing chamber and a water outlet chamber arranged in sequence along the water flow direction, and also has an air inlet channel connected to the water-gas mixing chamber. When the water flows into the water-gas mixing chamber through the water inlet channel, a negative pressure is formed in the water-gas mixing chamber by using the Venturi principle, so that the outside air is sucked into the water-gas mixing chamber through the air inlet channel. The spiral body is arranged in the water inlet channel, and is used to guide the incoming water flow into a rotating vortex and then enter the water-gas mixing chamber. A plurality of first convex portions are distributed in the water inlet channel at intervals, and the vortex hits the first convex portion after passing through the spiral body, and further enters the water-gas mixing chamber.

[0008] The Chinese invention (CN114849508A) discloses a microbubble water generating device, including a water flow conduit, a central control swirl assembly, a contraction section, a throat and an expansion section. The guide vane-type vortex-breaking plate is located downstream of the Venturi flow channel and is composed of a straight plate section and a bent section. By installing the central control swirl assembly, part of the water flow will suck in and mix the gas phase injected by the gas injection pipe when passing through the central cavity of the central control swirl assembly, thereby reducing the initial bubble particle size; the other part of the water flow forms a swirl under the action of the swirl blades, which helps the bubbles to be broken up in the Venturi flow channel. The guide vane-type swirl-breaking plate coaxially installed downstream of the Venturi flow channel can destroy the rotating wake, reduce the probability of collision and coalescence between microbubbles, and further homogenize and refine the bubbles to improve the bubble quality.

[0009] Current intellectual property data shows that there are already many devices on the market that are specifically used for irrigation and fertilization or for generating microbubbles in irrigation water. Most of these devices use the Venturi negative pressure suction principle: when the irrigation water flow enters the throat section, a negative pressure is formed, thereby sucking in air or liquid fertilizer, which is mixed with the irrigation water flow to generate bubble water or a water-fertilizer mixture. Although these devices can achieve the functions of irrigation and fertilization and oxygenation, the following problems still exist: large head loss, easy cavitation, unreasonable geometric design, excessive front-end pressure, etc. In addition, the bubbles generated are large, and the actual application efficiency is low. Therefore, there is an urgent need for a water-fertilizer-gas mixing device with a simple structure, cost-effectiveness, to overcome the defects of the prior art and improve irrigation efficiency and effectiveness. Summary of the invention

[0010] Technical problem to be solved: In view of a series of problems in the current Venturi water-fertilizer-gas mixing device, such as the non-compact structure, uneven bubble particle size, large head loss, and low efficiency, the present invention proposes a multi-port Venturi fertilization and oxygenation device, which can effectively reduce the fertilizer absorption pressure, increase the fertilizer absorption amount, and realize water-fertilizer-gas mixing at the same time, thereby improving the fertilizer absorption, oxygenation and mixing efficiency.

[0011] Technical solution: A multi-port Venturi fertilization and oxygenation device, comprising a liquid inlet section and a liquid outlet section, between which at least two sub-Venturi tubes are symmetrically arranged along the central axis, each sub-Venturi tube is provided with a contraction section, a throat section and an expansion section in sequence along the liquid flow direction, the contraction section is connected to the liquid inlet section, and the expansion section is connected to the liquid outlet section; a suction section is also provided on the throat section; the ratio of the length of the projection point of the center of the throat section projected on the cross section of the liquid inlet section to the center of the cross section of the liquid inlet section to the length of the radius of the cross section of the liquid inlet section is 0.2-0.8; the contraction angle of the contraction section is 35°-45°; the ratio of the radius of the throat section to the radius of the liquid inlet section is 0.20-0.30; the aspect ratio of the throat section is 1.0-1.25.

[0012] In one of the preferred solutions, the device is provided with two sub-Venturi tubes with completely the same structure and size, and the sub-Venturi tubes are arranged in parallel.

[0013] In another preferred embodiment, the device is provided with three sub-Venturi tubes with completely identical structures and sizes, and the sub-Venturi tubes are symmetrically arranged in the direction of the central axis between the liquid inlet section and the liquid outlet section.

[0014] The suction section is perpendicular to the axial direction of the corresponding sub-Venturi tube.

[0015] Preferably, the ratio of the length of the projection point of the center of the throat section projected onto the liquid inlet section cross section from the center of the liquid inlet section cross section to the radius of the liquid inlet section cross section is 0.5.

[0016] Preferably, the contraction angle between the contraction sections is 26.6°.

[0017] Preferably, the radius ratio of the throat section to the liquid inlet section is 0.2.

[0018] Preferably, the aspect ratio of the throat section is 1.0.

[0019] The liquid inlet section and the liquid outlet section are connected to pipelines through screw ports respectively.

[0020] Beneficial effects: (1) In the multi-port Venturi fertilization and oxygenation device described in the present invention, the fluid enters the liquid outlet section along the expansion section after slight contraction of the throat, and the throat section is eccentric relative to the expansion section and the liquid inlet section; the streamline change of the fluid from the throat to the expansion section is small, the separation effect of the pipe wall is weak, and the expansion section maintains a moderate vortex strength, which significantly improves the mixing effect.

[0021] (2) In addition, the device innovatively adopts the design concept of first dividing and then merging the flow. This structure greatly promotes the full blending and uniform distribution of the two-phase flow or three-phase flow during the mixing process, effectively improves the mixing quality and efficiency, and brings significant improvements to the fertilization and oxygenation operations.

[0022] (3) It is worth mentioning that the structure of the device is simple and practical, which is not only easy to install and maintain, but also will not affect the normal operation of the whole device even if a single diversion channel is damaged. This design greatly enhances the reliability of the device and effectively extends its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a schematic structural diagram of a multi-venturi fertilization and oxygenation device.

[0024] Figure 2 The present invention is a projection diagram of the throat of a multi-venturi fertilization and oxygenation device.

[0025] Figure 3 This is a velocity cloud diagram of a multi-port Venturi fertilization and oxygenation device provided in Example 1 of the present invention.

[0026] Figure 4 This is a pressure cloud diagram of a multi-port Venturi fertilization and oxygenation device provided in Example 1 of the present invention.

[0027] Figure 5 This is a turbulent kinetic energy cloud diagram of a multi-port Venturi fertilization and oxygenation device provided in Example 1 of the present invention.

[0028] Figure 6 This is a gas phase cloud diagram of a multi-port Venturi fertilization and oxygenation device and a conventional Venturi device provided in Example 1 of the present invention.

[0029] Figure 7This is a liquid phase cloud diagram of a multi-port Venturi fertilization and oxygenation device and a conventional Venturi device provided in Example 1 of the present invention.

[0030] Figure 8 This is a comparison chart of the intake volume of a multi-port Venturi fertilization and oxygenation device provided in Example 1 of the present invention and a conventional Venturi fertilization device.

[0031] Fig. 9 This is a comparison chart of the suction efficiency of a multi-port Venturi fertilization and oxygenation device provided in Example 1 of the present invention and a conventional Venturi fertilization device.

[0032] Fig.10 This is a schematic structural diagram of a multi-port Venturi fertilization and oxygenation device provided in Example 2 of the present invention.

[0033] Fig.11 This is a projection diagram of the throat of a multi-port Venturi fertilization and oxygenation device in Example 2 of the present invention.

[0034] Fig.12 This is a comparison chart of the intake volume of a multi-port Venturi fertilization and oxygenation device provided in Example 2 of the present invention and a conventional Venturi fertilization device.

[0035] Fig.13 This is a comparison chart of the suction efficiency of a multi-port Venturi fertilization and oxygenation device provided in Example 2 of the present invention and a conventional Venturi fertilization device.

[0036] Fig.14 This is a comparison chart of the suction volume of a multi-port Venturi fertilization and oxygenation device provided in Example 2 of the present invention when the suction section is blocked and that of a conventional Venturi fertilization device.

[0037] Fig.15 This is a comparison diagram of the suction efficiency of a multi-port Venturi fertilization and oxygenation device provided in Example 2 of the present invention when the suction section is blocked and that of a conventional Venturi fertilization device.

[0038] Description of reference numerals:

[0039] 1-liquid inlet section; 2-contraction section; 21-sub-contraction section; 3-throat section; 31-sub-throat section; 4-expansion section; 41-sub-expansion section; 5-liquid outlet section; 6-suction section; 61-sub-suction section. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with specific embodiments, and the advantages and features of the present invention will become clearer as the description proceeds. However, these embodiments are exemplary only and do not constitute any limitation to the scope of the present invention. It should be understood by those skilled in the art that the details and forms of the technical solution of the present invention may be modified or replaced without departing from the spirit and scope of the present invention, but these modifications and replacements all fall within the scope of protection of the present invention.

[0041] The purpose of the present invention is to provide a multi-port Venturi fertilization and oxygenation device, which can effectively facilitate field operations, improve fertilization and oxygenation efficiency, and promote the sustainable development of agriculture.

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] Example 1

[0044] According to the relevant principles of fluid dynamics, for the fluid in the same pipeline, its flow rate is inversely proportional to the area of ​​the flow cross section, that is, when the flow cross section area changes, the fluid flow rate will also change. Therefore, the cross-sectional area of ​​the throat section of the Venturi device suddenly shrinks relative to the cross-sectional area of ​​the water inlet section, and the fluid flow rate of the throat section increases rapidly and reaches the maximum value. At this time, a vacuum appears around the throat section wall, which is a negative pressure relative to the throat section. The material outside the Venturi device enters the interior of the Venturi tube through this pressure difference.

[0045] The present invention provides a multi-venturi fertilization and oxygenation device, such as Figure 1 , 2 As shown, a multi-port Venturi fertilization and oxygenation device comprises a liquid inlet section 1 and a liquid outlet section 5, wherein two sub-Venturi tubes are symmetrically arranged between the liquid inlet section 1 and the liquid outlet section 5 along the central axis direction, and each sub-Venturi tube is provided with a contraction section 2, a throat section 3 and an expansion section 4 in sequence along the liquid flow direction, wherein the contraction section 2 is connected to the liquid inlet section 1, and the expansion section 4 is connected to the liquid outlet section 5; the throat section 3 is also provided with a suction section 6, and the suction section 6 is perpendicular to the axial direction of the sub-Venturi tube to which it belongs; the ratio of the length of the projection point of the center of the throat section 3 projected on the cross section of the liquid inlet section 1 to the center of the liquid inlet section section to the length of the radius of the liquid inlet section section is 0.5; the contraction angle of the contraction section 2 is 26.6°; the ratio of the radius of the throat section 3 to the liquid inlet section 1 is 0.2; and the length-to-diameter ratio of the throat section 3 is 1.0. The liquid inlet section 1 and the liquid outlet section 5 are connected to pipelines through screw ports, respectively.

[0046] A specific implementation method of the Venturi fertilization and oxygenation device, taking water-fertilizer mixing as an example, Figure 1 As shown, the liquid inlet section 1 is divided into two directions along the flow direction, and the two sections of the contraction tube 2 are respectively connected to the throat section 3, and the connection is a smooth surface. Figure 2 As shown in the figure, the projections of the two contraction sections equally divide the cross-sectional area of ​​the water inlet section. Figure 3 As shown in FIG. 1 , when the angle between the inclined surfaces of the contraction section 2 and the sub-contraction section 21 is 26.6°, the diameter of the throat section is 5 mm, and the diameter of the suction section is 5 mm, the liquid flow rate reaches the fastest in the throat section 3, and the flow rate distribution of the two symmetrical contraction sections is also symmetrical, and the mixing effect between the two phases is better. Figure 4As shown, the static pressure at the front end of the sub-throat section 21 and the sub-expansion section 41 is negative, and the negative pressure area is relatively concentrated. Figure 5 As shown, the turbulent kinetic energy reflects the degree of turbulence of the fluid. The greater the turbulent kinetic energy, the stronger the collision between the fluids and the more thorough the mixing. The front end of the expansion section 4 initially performs liquid mixing, the kinetic energy is released, and then the water flows into the lower pipeline in a more stable flow state.

[0047] like Figure 6 , 7 As shown, a specific implementation of the Venturi fertilization and oxygenation device is taken as an example to compare the water-gas mixing of a conventional Venturi device. The gas phase enters the throat through the suction section 6, and then mixes with the fluid. The gas gradually mixes with the fluid along the wall of the expansion section and forms a series of bubble water. Compared with the conventional Venturi device, the gas phase distribution of this device is more uniform and the fluctuation is small; at the same time, due to the fragmentation and collision of the gas, the sub-Venturi tube close to the suction section 6 (or sub-suction section 61) is also prone to cavitation, which may cause damage to the device; therefore, during the production of the device, the side wall at this location should be appropriately thickened to reduce the impact of cavitation. Figure 7 As shown, the gas does not enter the fluid in the liquid inlet section 1 and the contraction section 2, and the gas volume fraction is 0. The gas enters through the throat section. Compared with the conventional Venturi device, the proportion of gas phase in the two-phase flow of this device is increased, the volume fraction of liquid phase is reduced, and the gas and liquid are mixed evenly.

[0048] like Figure 8 As shown, the abscissa of the coordinate system is the inlet pressure (kPa), the ordinate is the suction volume (kg / s), curve a is a conventional Venturi device, and curve b is the Venturi device in this embodiment. Compared with the conventional Venturi device (that is, the Venturi device with consistent geometric structure parameters and no flow separation or confluence), the mass flow rate of fertilizer suction of the Venturi device in this embodiment is increased by 28.34%-58.91%. Fig. 9 As shown, the horizontal axis of the coordinate system is the inlet pressure (kPa), the vertical axis is the suction efficiency (%), curve a is a conventional Venturi type device, and curve b is the Venturi type device in this embodiment. Compared with the conventional Venturi type device, the mass flow rate of the fertilizer suction amount of the Venturi type device in this embodiment is increased by 26.91%-57.65%.

[0049] Example 2

[0050] like Fig.10 , 11As shown, in this embodiment, the structure is similar to that of Embodiment 1, but three sub-Venturi tubes are symmetrically arranged along the central axis, that is, the contraction section 2, the throat section 3 and the expansion section 4 are all three parallel arranged, and the ratio of the length of the projection point of the center of the throat section 3 on the cross-section of the liquid inlet section 1 from the center of the liquid inlet section to the length of the radius of the liquid inlet section is 0.48; the contraction angle between the three sub-contraction sections 21 is 11.3°; the ratio of the radius of the throat section 3 to the liquid inlet section 1 is 0.20; the aspect ratio of the throat section 3 is 1.4; the line connecting the projection points of the centers of the three sub-throat sections 31 on the liquid inlet section 1 is an equilateral triangle.

[0051] like Fig.12 As shown, the horizontal axis of the coordinate system is the inlet pressure (kPa), the vertical axis is the suction volume (kg / s), curve a is a conventional Venturi type device, and curve b is the Venturi type device in this embodiment. Compared with the conventional Venturi type device, the mass flow rate of the fertilizer suction volume of the Venturi type device in this embodiment is increased by 56.64%-212.48%. Fig.13 As shown, the horizontal axis of the coordinate system is the inlet pressure (kPa), the vertical axis is the suction efficiency (%), curve a is a conventional Venturi device, and curve b is the Venturi device in this embodiment. Compared with the conventional Venturi device, the fertilizer suction efficiency of the Venturi device in this embodiment is improved by 3.60%-47.79%. (Compared with the conventional Venturi device, specifically under the gradient inlet pressure condition, 3.6% is the efficiency of the three-port geometric structure under low inlet pressure, and the device operates inefficiently under low inlet pressure)

[0052] like Fig.14 As shown, the horizontal axis of the coordinate system is the inlet pressure (kPa), the vertical axis is the suction volume (kg / s), curve a is a conventional Venturi device, curve b is the Venturi device in this embodiment, and curve c is the Venturi device in this embodiment with a suction section having a suction failure (assuming that the suction section is completely unable to extract fertilizer due to foreign body blockage, structural aging, or damage). Compared with the conventional Venturi device, the mass flow rate of the fertilizer suction volume of the Venturi device in this embodiment is still increased by 16.98%-199.39% when the suction section fails, especially when the inlet pressure is relatively high, the suction section failure has little effect on the fertilizer suction volume. Fig.15As shown, the horizontal axis of the coordinate system is the inlet pressure (kPa), and the vertical axis is the suction efficiency (%). Compared with the conventional Venturi type device, the fertilizer suction efficiency of the Venturi type device in this embodiment is still improved by 26.59% in the case of a suction section failure, while the fertilizer suction efficiency of the device in the embodiment without a suction section failure is only reduced by 13.81%. It is believed that the suction section failure has little effect on the fertilizer suction capacity of this Venturi device. In summary, the device further suppresses the occurrence of reduced suction quality and efficiency due to device failure, and increases the service life of the device.

[0053] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-port Venturi fertilization and oxygenation device, comprising a liquid inlet section (1) and a liquid outlet section (5), characterized in that: At least two sub-Venturi tubes are symmetrically arranged between the liquid inlet section (1) and the liquid outlet section (5) along the central axis direction. Each sub-Venturi tube is provided with a contraction section (2), a throat section (3) and an expansion section (4) in sequence along the liquid flow direction. The contraction section (2) is connected to the liquid inlet section (1), and the expansion section (4) is connected to the liquid outlet section (5). The throat section (3) is also provided with a suction section (6). The ratio of the length of the projection point of the center of the throat section (3) on the cross section of the liquid inlet section (1) to the center of the cross section of the liquid inlet section to the length of the radius of the cross section of the liquid inlet section is 0.2-0.

8. The contraction angle of the contraction section (2) is 35°-45°. The ratio of the radius of the throat section (3) to that of the liquid inlet section (1) is 0.20-0.

30. The length-to-diameter ratio of the throat section (3) is 1.0-1.

25.

2. A multi-port Venturi fertilization and oxygenation device according to claim 1, characterized in that: Two sub-Venturi tubes with completely the same structure and size are provided, and the sub-Venturi tubes are arranged in parallel.

3. A multi-port Venturi fertilization and oxygenation device according to claim 1, characterized in that: Three sub-Venturi tubes with completely identical structures and sizes are provided, and the sub-Venturi tubes are symmetrically arranged in the direction of the central axis between the liquid inlet section (1) and the liquid outlet section (5).

4. A multi-port Venturi fertilization and oxygenation device according to claim 1, characterized in that: The suction section (6) is perpendicular to the axial direction of the corresponding sub-Venturi tube.

5. A multi-port Venturi fertilization and oxygenation device according to claim 1, characterized in that: The ratio of the length of the projection point of the center of the throat section (3) on the cross section of the liquid inlet section (1) from the center of the cross section of the liquid inlet section to the length of the radius of the cross section of the liquid inlet section is 0.

5.

6. A multi-port Venturi fertilization and oxygenation device according to claim 1, characterized in that: The contraction angle between the contraction sections (2) is 26.6°.

7. A multi-port Venturi fertilization and oxygenation device according to claim 1, characterized in that: The radius ratio of the throat section (3) to the liquid inlet section (1) is 0.

2.

8. A multi-port Venturi fertilization and oxygenation device according to claim 1, characterized in that: The length-to-diameter ratio of the throat section (3) is 1.

0.

9. The multi-port Venturi fertilization and oxygenation device according to any one of claims 1 to 8, characterized in that: The liquid inlet section (1) and the liquid outlet section (5) are connected to pipelines via screw ports respectively.

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