Static pesticide and fertilizer mixing device, on-line pesticide and fertilizer mixing system and agricultural machine

Abstract

The application relates to the field of agricultural equipment and discloses a static pesticide and fertilizer mixing device, a direct injection type online pesticide and fertilizer mixing system and agricultural machinery. The static pesticide and fertilizer mixing device comprises a pesticide and fertilizer mixing device shell (100) and multiple groups of pesticide mixing units (200) arranged in the pesticide and fertilizer mixing device shell at intervals along the axial direction. Each group of pesticide mixing units comprises a first spoiler group and a second spoiler group arranged oppositely and respectively attached to the inner wall surface of the pesticide and fertilizer mixing device shell. The first spoiler group and the second spoiler group respectively have multiple inclined spoilers arranged at intervals along the axial direction and respectively formed with multiple flow holes. The inclined spoilers of the first spoiler group and the second spoiler group are arranged at an inclined direction opposite to each other and inclined to the axial direction of the pesticide and fertilizer mixing device shell. The static pesticide and fertilizer mixing device can ensure a low pressure drop, good mixing uniformity and a smallest possible uniformity variation coefficient, thereby improving the performance of the direct injection type online pesticide and fertilizer mixing system.

Description

Technical Field

[0001] This invention relates to agricultural equipment, specifically to a static pesticide and fertilizer mixer. Furthermore, this invention also relates to a direct-injection online pesticide and fertilizer mixing system and agricultural machinery incorporating the static pesticide and fertilizer mixer. Background Technology

[0002] Currently, most sprayers use a pre-mixing method for pesticide mixing. This involves manually or mechanically mixing a high-concentration pesticide solution with water in a tank, and then the sprayer's pump directly draws the solution from the tank for spraying. This method has many drawbacks, such as potential health hazards to operators during the mixing process, and waste and pollution if the mixed solution is not used promptly. Therefore, research on online pesticide mixing systems is of great value and practical significance. Online pesticide mixing refers to storing the pesticide solution and water separately, and then using a water pump and a pesticide pump to draw the water and high-concentration pesticide solution into a mixer in real time for mixing when needed. This mixing method reduces the health hazards to operators during the mixing process and minimizes pesticide waste.

[0003] Online pesticide mixing systems can be mainly divided into two types: direct injection and jet mixing. Direct injection relies on external power to draw high-concentration pesticide solution into the main pipeline and mixes it with water via a static mixer. It offers advantages such as convenient installation, small size, and high mixing efficiency. Jet mixing primarily uses a jet mixer, based on the principle of a Venturi tube. As the high-speed liquid passes through the jet tube, a negative pressure is created outside the outlet, drawing the high-concentration pesticide solution from the tank into the jet mixer for further mixing within the pipeline. Its advantages include low energy consumption and simple structure, but it suffers from problems such as insufficient mixing and inaccurate mixing ratios.

[0004] The main factors affecting the performance of direct-injection online mixing systems include the response time delay of mixing ratio adjustment and the uniformity of drug-water mixing. Existing technologies typically improve these factors through optimization of the mixer structure or piping. However, traditional drug injection methods usually involve pumping the drug into the mixing system using a metering pump. When the mixing ratio is relatively small, the pump's constant displacement generates significant flow pulsations in the injected drug, greatly reducing the mixing uniformity over time and severely impacting the performance of the direct-injection online mixing system. Summary of the Invention

[0005] The purpose of this invention is to overcome the poor performance of existing direct injection online mixing systems and to provide a static mixing device and a direct injection online mixing system including the static mixing device. The static mixing device can achieve good mixing uniformity and the smallest possible uniformity variation coefficient while ensuring a low pressure drop, thereby improving the performance of the direct injection online mixing system.

[0006] To achieve the above objectives, the present invention provides a static pesticide and fertilizer mixing device, comprising:

[0007] A mixing device housing, wherein an injection port and an outlet are respectively provided at both axial ends of the mixing device housing;

[0008] Multiple sets of mixing units are arranged axially spaced within the mixing unit housing. Each set of mixing units includes a first baffle group and a second baffle group arranged opposite to each other and respectively attached to the inner wall surface of the mixing unit housing. The first baffle group and the second baffle group each have multiple inclined baffles arranged axially spaced and each having multiple flow holes. The inclined baffles of the first baffle group and the second baffle group are inclined relative to the axial direction of the mixing unit housing in opposite directions.

[0009] Preferably, multiple sets of the mixing units are connected as one unit by multiple connecting rods extending along the axial direction parallel to the mixing device housing.

[0010] Preferably, the static mixing device includes three sets of mixing units arranged axially spaced apart from each other within the mixing device housing, wherein the first and second baffle groups in each set of mixing units are arranged in phase within the mixing device housing, and / or, the first and second baffle groups each have four inclined baffles arranged parallel to each other at equal intervals along the axial direction.

[0011] Preferably, the tilt angle α of the inclined baffle relative to the axial direction of the mixer housing is 30°-80°, and more preferably 50°-60°.

[0012] Preferably, the spacing L between adjacent mixing units is 10mm-23mm, and more preferably 22mm-23mm.

[0013] Preferably, the diameter d of the flow passage is 1mm-2mm, and more preferably 1.5mm-1.8mm.

[0014] A second aspect of the present invention provides a direct injection online mixing system for pesticides and fertilizers, comprising the above-mentioned static mixing device for pesticides and fertilizers, as well as a water-solvent injection path and a pesticide injection path. The water-solvent injection path and the pesticide injection path are connected to the injection port through an injection pipeline equipped with a first conductivity transmitter, and the discharge port is connected to a discharge pipeline equipped with a second conductivity transmitter.

[0015] Preferably, the liquid injection path includes a pressure tank, a flow regulating valve for adjusting the flow rate of the liquid delivered from the pressure tank to the injection pipeline, and an overflow path connecting the pressure tank and the liquid tank. The overflow path includes an electromagnetic overflow valve and an accumulator for adjusting the pressure inside the pressure tank.

[0016] Preferably, the injection pipeline is further provided with a first pressure transmitter, the liquid injection flow line is provided with a second pressure transmitter for detecting the pressure of the liquid medicine delivered from the pressure tank to the injection pipeline, and / or, the water solvent injection flow line is provided with a water solvent flow transmitter, and the liquid medicine injection flow line is provided with a liquid medicine flow transmitter.

[0017] Preferably, the system further includes a controller connected to the first and second conductivity transmitters, which is capable of controlling the opening degree of the flow regulating valve and / or the overflow pressure of the electromagnetic relief valve based on the detection signals from the first and second conductivity transmitters.

[0018] Preferably, the end of the discharge pipe away from the static mixing and fertilizer mixer is connected to a liquid spray bar, which is equipped with multiple nozzles.

[0019] A third aspect of the present invention provides an agricultural machine comprising the above-described static pesticide and fertilizer mixer or a direct injection online pesticide and fertilizer mixing system.

[0020] Through the above technical solution, water-soluble solvent and high-concentration pesticide solution can be injected into the mixer housing through the injection port. Under the action of the kinetic energy of the water-soluble solvent itself, the high-concentration pesticide solution can flow to the discharge port. During the flow process, multiple sets of mixing units cause the water-soluble solvent and pesticide solution to be divided and merged, and guided to generate complex movements such as rotation. This can better maintain the pesticide solution pressure, obtain good mixing uniformity and the smallest possible uniformity variation coefficient while ensuring a low pressure drop, and improve the performance of the direct injection online mixing system. Attached Figure Description

[0021] Figure 1 This is a structural schematic diagram of a static pesticide and fertilizer mixer according to a preferred embodiment of the present invention.

[0022] Figure 2 It is observed from another perspective. Figure 1 A schematic diagram of the static pesticide and fertilizer mixer, in which the mixer housing has been removed;

[0023] Figure 3 It is after the mixing device housing has been removed Figure 1 A schematic diagram of the static pesticide and fertilizer mixer in the diagram;

[0024] Figure 4 It is viewed from an axial perspective. Figure 1 A schematic diagram of the static pesticide and fertilizer mixer in the diagram;

[0025] Figure 5 This is a schematic diagram of a direct injection online mixing system for pesticides and fertilizers according to a preferred embodiment of the present invention.

[0026] Figure 6a These are single-factor test curves showing the effect of the tilt angle of the tilted baffle on pressure drop and drug mixing uniformity.

[0027] Figure 6b These are single-factor experimental curves showing the effect of the spacing between mixing units on pressure drop and mixing uniformity.

[0028] Figure 6c These are single-factor test curves showing the effect of orifice diameter on pressure drop and drug mixing uniformity.

[0029] Figure 6d It is a single-factor test curve showing the effect of the orifice diameter of the central hole on pressure drop and drug mixing uniformity;

[0030] Figure 7 It is the response surface of the tilt angle of the tilted spoiler and the spacing between the mixing units with respect to the pressure drop;

[0031] Figure 8 It is the response surface of the tilt angle of the tilted spoiler and the orifice diameter with respect to the pressure drop;

[0032] Figure 9 It is the response surface of the tilt angle of the tilted baffle and the spacing between the mixing units to the coefficient of variation of the mixing concentration;

[0033] Figure 10 It is the response surface of the tilt angle of the tilted baffle and the orifice diameter to the coefficient of variation of the mixed drug concentration.

[0034] Figure 11 It is a Pareto front diagram for multi-objective optimization using a genetic algorithm;

[0035] Figure 12 This is a graph showing the coefficient of variation and principal component distribution at different cross-sectional locations;

[0036] Figure 13This is a graph showing the pressure drop trends of three different mixers within the Reynolds number range of 10,000-30,000.

[0037] Figure 14 This is a graph showing the trend of the coefficient of variation of uniformity for three different mixing devices in the Reynolds number range of 10,000-30,000.

[0038] Figure 15 This is a schematic diagram of a direct injection online mixing system for pesticides and fertilizers according to another preferred embodiment of the present invention.

[0039] Explanation of reference numerals in the attached figures

[0040] 100 - Mixer housing; 110 - Inlet; 120 - Outlet; 200 - Mixing unit; 210 - Inclined baffle; 220 - Flow hole; 230 - Center hole; 300 - Connecting rod;

[0041] 1-First DC brushless motor; 2-Plunger pump; 3-Water tank; 4-Overflow valve; 5-Water solvent flow transmitter; 6-Check valve; 7-Pesticide flow transmitter; 8-Flow regulating valve; 9-Second pressure transmitter; 10-Pressure tank; 11-Diaphragm pump; 12-Second DC brushless motor; 13-Pesticide tank; 14-Solenoid overflow valve; 15-Accumulator; 16-First pressure transmitter; 17-First conductivity transmitter; 18-Static pesticide / fertilizer mixer; 19-Second conductivity transmitter; 20-Third pressure transmitter; 21-Pesticide flow transmitter; 22-Sprayer head; 23-Controller. Detailed Implementation

[0042] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0043] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "left," and "right" generally refer to the upper, lower, left, and right as shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0044] Reference Figures 1 to 4 As shown, one aspect of the present invention provides a static pesticide and fertilizer mixer, which can be used for, for example Figure 5The static pesticide and fertilizer mixer, as shown or in other forms, is a direct injection online mixing system. It includes a mixer housing 100 and an internal mixing assembly disposed within the housing 100. The housing 100 is generally cylindrical, with an inlet 110 and an outlet 120 at its axial ends. The inlet 110 allows the water-soluble solvent and a high-concentration pesticide solution to be mixed to be injected into the housing 100, mixed within the housing, and discharged through the outlet 120 for application, such as in farmland. It should be understood that the high-concentration pesticide solution described herein is not limited to pesticides applied to farmland, but can also include, for example, foliar fertilizers applied to plant leaves. Therefore, although described as a "mixer," the static pesticide and fertilizer mixer of the present invention can also be used to mix water and fertilizer.

[0045] The internal mixing assembly includes multiple sets of mixing units 200 arranged axially spaced within the mixer housing 100. In the preferred embodiment illustrated, the mixer housing 100 contains three sets of mixing units 200, which have identical structures and arrangements (described in detail later). Each set of mixing units 200 includes a first spoiler group and a second spoiler group arranged opposite to each other, i.e., with the central axis of the mixer housing 100 as a reference, the first spoiler group and the second spoiler group are arranged radially opposite to each other.

[0046] The first and second spoiler groups each have a plurality of inclined spoilers 210 arranged at intervals along the axial direction. Each inclined spoiler 210 has a plurality of flow holes 220 formed thereon, and its outer periphery is in contact with the inner wall surface of the mixer housing 100. In such cases... Figure 4 In the illustrated embodiment, the flow holes 220 on the inclined spoiler 210 are generally circular or semi-circular, and each inclined spoiler 210 has 13 circular flow holes 220 and 4 semi-circular flow holes 220. In addition, a central hole 230 may also be formed on the inclined spoiler 210 at the position corresponding to the central axis of the mixer housing 100.

[0047] The inclined spoilers 210 of the first and second spoiler groups are arranged at opposite inclination directions relative to the axial direction of the mixer housing 100. That is, in the case of... Figures 1 to 3 From the perspective shown, the inclined baffles 210 of the first baffle group and the inclined baffles 210 of the second baffle group are arranged crosswise. As a result, fluids such as water solvent and high-concentration drug solution injected through the injection port 110 can be guided by the mixing unit (the inclined baffles 210 and the flow holes 220 formed on them) in the mixing unit 100 to form a complex and chaotic flow path, such as flowing along the inclined direction of the inclined baffles 210, flowing through the flow holes 220, or flowing between the first baffle group and the second baffle group.

[0048] Using the aforementioned static pesticide and fertilizer mixer, water-soluble solvents and high-concentration pesticide solutions can be injected into the mixer housing 100 through the injection port 110. Under the action of the kinetic energy of the water-soluble solvent itself, during the flow process, multiple sets of mixing units 200 cause the water-soluble solvent and pesticide solution to be divided and combined, and guided to generate complex movements such as rotation. This can better maintain the pesticide solution pressure, obtain good mixing uniformity and the smallest possible uniformity variation coefficient while ensuring a low pressure drop, and improve the performance of the direct injection online pesticide and fertilizer mixing system.

[0049] Multiple mixing units 200 can be installed at equal intervals within the mixer housing 100 in various ways. In the illustrated preferred embodiment, the internal mixing assembly further includes multiple connecting rods 300 extending axially parallel to the mixer housing 100. The illustration shows four connecting rods 300 evenly distributed around the central axis of the mixer housing 100. The multiple mixing units 200 are connected as a whole by these connecting rods 300 and are configured to have the same spacing between them. The two ends of the internal mixing assembly may be provided with fixing components to secure the mixing units 200 inside the mixer housing 100.

[0050] In the static mixing device of the present invention, the mixing device housing 100 may contain an appropriate number of mixing units 200, not limited to the three groups shown in the figure. Each group of mixing units 200 may be arranged in phase within the mixing device housing 100, meaning that the first and second baffle groups of each group of mixing units 200 have the same circumferential relative position to the mixing device housing 100. In the preferred embodiment shown in the figure, the first and second baffle groups each have four inclined baffles 210 arranged parallel to each other at equal intervals along the axial direction.

[0051] It should be understood that although the terms "first" and "second" are used to distinguish between the first spoiler group and the second spoiler group, this is only for clarity, and the tilting spoilers 210 of the two groups can have exactly the same structure. Therefore, in Figure 4 In the view shown, the semi-circular flow holes formed on the inclined spoiler 210 of the first spoiler group and the semi-circular flow holes formed on the inclined spoiler 210 of the second spoiler group are displayed as a combined circular hole.

[0052] For key evaluation factors of the static pesticide and fertilizer mixer's performance, such as pressure drop, mixing uniformity, and coefficient of variation of uniformity, the tilt angle of the inclined baffle 210 and the orifice diameter of the flow hole 220 may have a significant impact. To address this, the inventors have conducted in-depth research, optimized, and verified the preferred design parameters for the static pesticide and fertilizer mixer:

[0053] Based on the structure of the designed static mixing device and the actual working requirements, the tilt angle α of the inclined baffle relative to the axial direction of the mixing device housing is set to be 30°-80°, the spacing L between adjacent mixing units is set to be 10mm-23mm, the diameter d of the flow hole is set to be 1mm-2mm, and the diameter D of the center hole is set to be 2mm-4mm.

[0054] The friction coefficient of fluid flow inside an empty pipe can be calculated using the Colebrook formula, which is widely used to calculate the friction coefficient of turbulent fluids within pipes. The Colebrook formula is shown below:

[0055]

[0056] Where Δ is the absolute roughness of the pipe, d is the pipe diameter, Re is the Reynolds number, and λ is the friction coefficient. The friction coefficient of the empty pipe under different conditions can then be calculated.

[0057] The pressure drop of a fluid flowing inside an empty pipe can be calculated using the Darcy-Weisbach equation, which is shown below:

[0058]

[0059] Where f is the friction coefficient, L is the length of the empty pipe, ρ is the fluid density, V is the average velocity inside the pipe, and D is the pipe diameter, the pressure drop of the empty pipe under different Reynolds numbers can be calculated.

[0060] Table 1 Calculation results of relevant parameters

[0061]

[0062]

[0063] There are two main evaluation indicators for the performance of static pesticide and fertilizer mixers: the Z-factor and the coefficient of variation (CoV) for uniformity. The Z-factor is defined as the ratio of the pressure drop ΔP of the static pesticide and fertilizer mixer to the pressure drop ΔP0 of the empty pipe under the same parameters. It can be used to compare the degree of pressure drop loss in the static pesticide and fertilizer mixer. The Z-factor can be derived from the following formula:

[0064]

[0065] The pressure drop of the static pesticide and fertilizer mixer refers to the root mean square value of the pressure between the full inflow section (25mm) and the cross section at the 120mm position of the static pesticide and fertilizer mixer. The total pressure difference between the two sections is calculated using ANSYS-Fluent software, and the Z factor is calculated from the ratio.

[0066] The coefficient of variation for homogeneity of CoV is defined as the coefficient of variation of the local mass fraction of the mixed drug solution at a large number of points on a cross-section, and is usually derived by the following formula:

[0067]

[0068] Among them, Y i Y represents the local mass fraction of the mixed drug solution at point i, N is the total number of points, and Y represents the mass fraction of the mixed drug solution at point i. mean This represents the average mass fraction of the mixed drug solution at this interface. Based on the calculated coefficient of variation (CPV), the fluctuations in the mass fraction of the mixed drug solution at different cross-sections can be compared. Better mixing uniformity results in smaller fluctuations in mass fraction and a smaller CPV value, and vice versa.

[0069] Single-factor experiment

[0070] First, a single-factor experiment was conducted on the basic structural parameters of the static pesticide and fertilizer mixer. The single-factor experiment can be understood as judging the influence of a single factor on the evaluation index within a certain range. It is mainly used to judge its initial trend of change. Since the interaction effect is not considered at this time, the boundary value can be taken within a reasonable range.

[0071] In the single-factor experiment, the median values ​​of the remaining factors were taken, namely, the tilt angle α of the inclined baffle was 55°, the spacing L between adjacent mixing units was 16.5 mm, the orifice diameter d was 1.5 mm, and the orifice diameter D of the center hole was 3 mm. The simulation conditions were set as follows: water solvent inflow velocity 0.6 m / s and drug inflow velocity 0.3 m / s. Numerical simulations were performed separately for each influencing factor, and the results are as follows: Figures 6a to 6d As shown.

[0072] Among them, the effect of the tilt angle of the tilted baffle on pressure drop and mixing uniformity is as follows: Figure 6a As shown, the pressure drop of the mixer exhibits a decreasing trend, while the uniformity coefficient of variation shows an increasing trend. The effect of the spacing between mixing units on the pressure drop and mixing uniformity is as follows: Figure 6b As shown, the pressure drop in the mixer exhibits a decreasing trend, while the coefficient of variation for uniformity shows an increasing trend. The effect of the orifice diameter on the pressure drop and mixing uniformity is as follows: Figure 6c As shown, the pressure drop of the mixer shows an increasing trend, while the uniformity coefficient of variation shows a decreasing trend. Specifically, the uniformity coefficient of variation decreases rapidly when the tilt angle of the inclined baffle is 30°-55°, and decreases slowly when the tilt angle of the inclined baffle is 55°-80°. The effect of the orifice diameter of the central hole on the pressure drop and mixing uniformity is as follows. Figure 6d As shown, the pressure drop of the mixer shows a decreasing trend, and the coefficient of variation of uniformity also shows a decreasing trend.

[0073] Plackett-Burman screening (PB screening test)

[0074] This experiment screened four factors (tilt angle of the tilted spoiler X1, orifice diameter of the center hole X2, spacing between mixing units X3, and orifice diameter of the flow hole X4). Based on the experimental settings of Plackett-Burman screening in Design-Expert 13, reasonable boundary values ​​were selected based on the results of the above single-factor experiments, and a center value was added to enhance the curve fitting option.

[0075] Table 2. Significance analysis of the effects of various factors on the pressure drop of the mixer.

[0076]

[0077] The significance analysis of the effects of each factor on the pressure drop is shown in Table 2. The tilt angle X1 of the inclined baffle has a significant effect on the pressure drop of the mixer (P<0.01), the orifice diameter X4 of the flow orifice has a relatively large effect on the pressure drop of the mixer (P<0.05), and the orifice diameter X2 of the center hole and the spacing X3 between the mixing units have no significant effect on the pressure drop of the mixer (P>0.05). That is, the order of the influence of each factor on the pressure drop of the mixer is: tilt angle X1 of the inclined baffle > orifice diameter X4 > spacing between mixing units X3 > orifice diameter X2 of the center hole.

[0078] Table 3. Significance analysis of the effects of various factors on the coefficient of variation of the mixed drug solution concentration.

[0079]

[0080] The significance analysis of the effects of each factor on the uniformity coefficient of variation is shown in Table 3. The tilt angle X1 of the tilted baffle and the spacing X3 between the mixing units have a significant impact on the uniformity coefficient of variation (P<0.05), while the diameter X2 of the central hole and the diameter X4 of the flow orifice have no significant impact on the uniformity coefficient of variation (P>0.05). That is, the order of the influence of each factor on the uniformity coefficient of variation is: tilt angle X1 of the tilted baffle > spacing X3 between the mixing units > diameter X4 of the flow orifice > diameter X2 of the central hole.

[0081] In summary, the analysis shows that the tilt angle X1 of the inclined baffle, the spacing X3 between the mixing units, and the orifice diameter X4 of the flow passage have a significant impact on the pressure drop and uniformity variation coefficient of the static mixing device, while the orifice diameter X2 of the central orifice has no significant effect. Therefore, the tilt angle X1 of the inclined baffle, the spacing X3 between the mixing units, and the orifice diameter X4 are selected as the three factors for further Box-Behnken response surface methodology experiments.

[0082] Box-Behnken response surface methodology

[0083] This experiment employed a three-factor, three-level orthogonal combined experimental method, selecting the baffle tilt angle, mixing unit spacing, and flow orifice diameter as experimental factors. The pressure drop Y of the static mixing device and the coefficient of variation (CoV) of the uniformity of the pesticide solution after passing through the static mixing device were used as evaluation indicators for the orthogonal experiment. Table 4 shows the coding table for the experimental factors.

[0084] Table 4. Coding Table of Experimental Factors

[0085]

[0086] The experimental results are shown in Table 5, where A, B, and C are the coded values ​​of each experimental factor.

[0087] Table 5 Experimental Design and Results

[0088]

[0089] Design-Expert 13 software was used to perform a three-dimensional regression analysis on the experimental results, and a multiple regression fitting was performed on each experimental index to obtain the regression equations for the pressure drop and uniformity coefficient of variation of the static pesticide and fertilizer mixer. A significance analysis was also conducted on each experimental factor and its interaction. The analysis results for pressure drop and uniformity coefficient of variation are shown in Tables 6 and 7, respectively. Insignificant factors were classified as residuals, thus the regression equations for each experimental factor with respect to the pressure drop and uniformity coefficient of variation of the static pesticide and fertilizer mixer are as follows:

[0090] Y=2555+2429A+95.75B-302.25C+164.5AB-1032.5AC-109.25BC+502.62A 2 -31.13B 2 -128.12C 2 +76.75A 2 B-838.75A 2 C+26.5AB 2

[0091] CoV=0.0031-0.0018A-0.0012B-0.0009C+0.0000AB+0.0007AC+0.0007BC+0.0015A 2 +0.0005B 2 +0.0015C 2 +0.0020A 2 B+0.0033A 2 C+0.0008AB 2

[0092] Table 6. Analysis of Variance of Pressure Drop in Mixer

[0093]

[0094] Table 7. Analysis of Variance of Coefficient of Variation for Homogeneity

[0095]

[0096] The data in Table 6 were processed using Design-Expert 13 software to obtain the response surface of the tilt angle of the tilted spoiler and the spacing between the mixing units to the pressure drop evaluation index, as shown below. Figure 7 As shown, when the orifice diameter is constant, the pressure drop increases with the increase of the tilt angle of the inclined baffle; the pressure drop also increases with the increase of the spacing between the mixing units. The response surface of the tilt angle of the inclined baffle and the orifice diameter to the pressure drop evaluation index is obtained, as shown below. Figure 8 As shown, as the tilt angle of the tilted spoiler decreases and the diameter of the flow orifice increases, the pressure drop decreases to its minimum value.

[0097] The data in Table 7 were processed using Design-Expert 13 software to obtain the response surface of the tilt angle of the tilted spoiler and the spacing between the mixing units to the uniformity variation coefficient, as shown in the figure. Figure 9 As shown, when the orifice diameter is constant, the uniformity variation coefficient first decreases and then increases with the increase of the tilt angle of the inclined baffle; similarly, the uniformity variation coefficient first decreases and then increases with the increase of the spacing between mixing units. The response surfaces of the tilt angle of the inclined baffle and the orifice diameter to the uniformity variation coefficient are obtained, as shown below. Figure 10 As shown, the uniformity variation coefficient decreases to its lowest value as the tilt angle of the tilted spoiler increases and the diameter of the flow holes decreases.

[0098] Multi-objective optimization of the mixing device structure based on genetic algorithm

[0099] To avoid erroneously finding a local optimum while searching for the optimal solution among many better solutions, a genetic algorithm in Matlab is used to perform multi-objective optimization of the best structure of the static fertilizer and pesticide mixer.

[0100] Based on the above analysis of the response surface, the following mathematical model for the genetic algorithm can be derived:

[0101]

[0102] According to standards in the food, pharmaceutical, and chemical industries, a common mixing standard is to control the coefficient of variation of uniformity below 5%. The static pesticide and fertilizer mixer of this invention, as a mixing element for the pesticide solution, aims to ensure that high-concentration pesticide solution and water are mixed as uniformly as possible under conditions of low pressure drop. The mixing effect directly determines the working quality of the sprayer; therefore, a low coefficient of variation of uniformity and a low pressure drop are taken as optimization objectives. The Pareto front diagram for multi-objective optimization using a genetic algorithm is shown below. Figure 11 As shown.

[0103] According to the Pareto front, as the predicted pressure drop increases within the range of 0-0.28, the coefficient of variation for predicted uniformity approximately follows a quadratic curve F. CoV =1.105 - 5.87P + 9.763P 2 The predicted pressure drop decreases (P ranges from 0 to 0.28). When the predicted pressure drop increases within the range of 0.28-1, the predicted coefficient of variation decreases slowly, approximately following a straight line with a slope of K2 = -0.167, and within the quadratic function F... CoV The derivative at (0.28, 0.24) is K1 = -0.403. The diagram shows that the Pareto front is convex and a clear inflection point can be observed at (0.28, 0.24). This inflection point can be seen as a dynamic equilibrium reached between the two optimization objectives. Fitting the two straight lines of the Pareto front yields |K1| > |K2|. After the inflection point, further improving mixing uniformity requires sacrificing a significant predicted pressure drop, which contradicts the main objective of structural optimization (to achieve the smallest possible uniformity coefficient of variation while ensuring a low pressure drop). Therefore, the parameter value corresponding to the inflection point should be the optimal solution. It is found that when the tilt angle of the inclined baffle is 55.38°, the spacing between mixing units is 22.64 mm, and the orifice diameter is 1.64 mm, the uniformity coefficient of variation is minimized under the condition of a low pressure drop.

[0104] Simulation Result Analysis

[0105] Through the above multi-objective optimization, the optimized design parameters of the static pesticide and fertilizer mixer were obtained. Simulation experiments were conducted under these parameter combinations, and a comparative analysis was performed on two existing classic pesticide mixers (SMX type and Kenics type) under the same conditions (water solvent inflow velocity 0.6 m / s, pesticide inflow velocity 0.3 m / s). Figure 12 The figure shows the coefficient of variation and principal component distribution at different cross-sectional locations.

[0106] Depend on Figure 12It can be seen that, within the cross-sectional area of ​​30-150mm, the uniformity variation coefficients of the three types of mixers all show a decreasing trend, and the uniformity variation coefficient at the end of the static mixer drops below 0.01. The mixing performance of the static mixer provided by this invention is between that of the SMX and Kenics mixers, and the uniformity variation coefficient of the mixed liquid at the end of the mixer can be reduced to 0.00228. Therefore, the static mixer of this invention has good mixing performance. Figure 12 It also shows the principal component distribution at different cross-sectional positions, which allows for a direct observation of the mixing of the liquid medicine at different cross-sectional positions in the static medicine and fertilizer mixer.

[0107] The pressure drop trends of the three mixers in the Reynolds number range of 10,000-30,000 are as follows: Figure 13 As shown, the pressure drop of all three mixers increases with increasing Reynolds number, and the Kenics-type mixer has the lowest pressure drop due to its spiral structure. The SMX-type mixer has the largest pressure drop due to its complex internal structure, while the static mixing and fertilizer mixing device of this invention has a pressure drop in the middle of the two.

[0108] The trends of the coefficient of variation of homogeneity of the three mixers in the Reynolds number range of 10,000-30,000 are as follows: Figure 14 As shown, the Kenics mixer exhibits significant fluctuations in its uniformity coefficient of variation with increasing Reynolds number, resulting in a large overall coefficient of variation. Therefore, its mixing uniformity cannot be guaranteed under high Reynolds number conditions. The complex internal structure of the SMX mixer minimizes its uniformity coefficient of variation, but it slightly increases at higher Reynolds numbers (25000-30000). In contrast, the static pesticide and fertilizer mixer of this invention exhibits a uniformity coefficient of variation that is intermediate between the two and relatively stable. Therefore, it ensures a more balanced and stable mixing uniformity, thus better guaranteeing the working quality of the sprayer.

[0109] This invention optimizes parameters such as the tilt angle of the inclined baffle, the spacing between mixing units, and the diameter of the flow orifice through PB screening and three-factor, three-level orthogonal experiments. A genetic algorithm is then used to perform multi-objective optimization on multiple sets of optimal solutions to ultimately obtain the optimal solution. Therefore, the static pesticide and fertilizer mixer of this invention can achieve the smallest possible coefficient of variation in uniformity while ensuring a low pressure drop, facilitating the improvement of the performance of direct-injection online pesticide and fertilizer mixing systems.

[0110] Based on the static pesticide and fertilizer mixer provided by the present invention, another aspect of the present invention provides a direct injection online pesticide and fertilizer mixing system having the static pesticide and fertilizer mixer. For example... Figure 5As shown, this direct-injection online mixing system includes a water-solvent injection path and a pesticide injection path. The water-solvent injection path is connected to the injection port of the static mixing device 18 via an injection pipe, enabling the water-solvent in the water tank 3 to be injected into the static mixing device 18. The pesticide injection path is connected to the injection port of the static mixing device 18 via an injection pipe, enabling the injection of high-concentration pesticide solution from the pesticide tank 13 into the static mixing device 18. After the water-solvent and high-concentration pesticide solution injected into the static mixing device 18 are fully mixed, they are discharged through the outlet, which can be connected to a discharge pipe to supply the mixed pesticide to the sprayed area.

[0111] The static pesticide and fertilizer mixer 18 is equipped with conductivity transmitters, namely the first conductivity transmitter 17 and the second conductivity transmitter 19 shown in the figure, on the injection and discharge pipelines before and after the mixer. This allows for concentration detection of the mixed pesticide solution before and after the mixer, enabling online monitoring of the mixing uniformity. By comparing the detection results with the target mixing ratio and calculating the coefficient of variation of the concentration uniformity at different time points using a host computer, the performance of the direct injection online pesticide and fertilizer mixing system can be monitored in real time. This facilitates timely shutdown and maintenance in case of malfunctions, ensuring spray quality.

[0112] In this direct-injection online mixing system for pesticides and fertilizers, the water-solvent injection path and the pesticide injection path are also equipped with other components and devices for realizing and optimizing fluid injection. (Continue to refer to...) Figure 5 As shown, the water solvent injection path may include a plunger pump 2 driven by a first DC brushless motor 1, which can be driven to pump the water solvent in the water tank 3 to the static mixing agent 18. An overflow path connected to the water tank 3 is provided in the side of the pumping path of the plunger pump 2, and an overflow valve 4 is provided on the overflow path. A water solvent flow transmitter 5 may also be provided on the water solvent injection path for monitoring the flow rate of the pumped water solvent.

[0113] The drug injection path may include a diaphragm pump 11 driven by a second DC brushless motor 12. This diaphragm pump 11 is driven to pump high-concentration drug solution from the drug tank 13 to the pressure tank 10, and then the high-concentration drug solution is delivered to the static drug-fertilizer mixer 18. The drug injection path includes the pressure tank 10 and a flow regulating valve 8 for adjusting the flow rate of the drug solution delivered from the pressure tank 10 to the injection pipeline. This flow regulating valve 8 may be an electrically operated valve. The pressure tank 10 is connected to an overflow path leading to the drug tank 13. This overflow path includes an electromagnetic overflow valve 14 and an accumulator 15 for adjusting the pressure within the pressure tank 10. A drug flow transmitter 7 may also be provided in the drug injection path to monitor the flow rate of the delivered high-concentration drug solution. A check valve 6 may also be provided in the portion of the drug injection path connected to the injection pipeline.

[0114] In addition, a first pressure transmitter 16 may be installed on the injection pipeline, and a second pressure transmitter 9 may be installed on the liquid injection flow path to detect the pressure of the liquid delivered from the pressure tank 10 to the injection pipeline.

[0115] In a preferred embodiment of the present invention, the direct injection online mixing system for pesticides and fertilizers may further include a controller 23. This controller 23 is signal-connected to a first conductivity transmitter 17 and a second conductivity transmitter 19, and can control the opening of the flow regulating valve 8 and / or the overflow pressure of the electromagnetic overflow valve 14 based on the detection signals from the first conductivity transmitter 17 and the second conductivity transmitter 19. Thus, by controlling the injection pressure of the pesticide solution through the electromagnetic overflow valve 14 and controlling the inflow area of ​​the pesticide solution into the mixing system through the opening of the flow regulating valve 8, the controller 23 calculates the optimal solution for these two variables (pressure and opening), which has the advantage of a smaller response time delay compared to the single-variable (opening) control method of traditional mixing systems for pesticides and fertilizers.

[0116] In the preferred embodiment shown in the figure, the controller 23 is also connected to the water solvent flow transmitter 5, the drug liquid flow transmitter 7, the first pressure transmitter 16 and the second pressure transmitter 9, etc., so as to obtain relevant flow and pressure parameters in real time and achieve precise control.

[0117] Furthermore, this direct-injection online mixing system can have a liquid spray bar connected to the end of the discharge pipeline away from the static mixing device 18, and the liquid spray bar is equipped with multiple nozzles 22. The discharge pipeline can also be equipped with a third pressure transmitter 20 and a pesticide flow transmitter 21, both of which are connected to the controller 23.

[0118] The following combination Figure 5 The working process of the direct injection online mixing system for pesticides and fertilizers according to a preferred embodiment of the present invention will be described by way of example:

[0119] Based on the mixing ratio signal input by the operator at the external terminal, the controller 23 calculates the target signals for the water solvent flow rate and the drug injection flow rate and outputs them to the water pump control circuit and the drug pump control circuit. The plunger pump 2 pumps the target flow rate of water solvent into the mixing system based on the received signal; the diaphragm pump 11 pumps the target flow rate of drug solution into the drug injection system (not the drug flow rate injected into the static mixing device, but the total drug flow rate). Optimal control parameters are selected based on the shortest response time and output to the voltage and current output circuits of the controller 23. These voltage and current signals control the given pressure of the electromagnetic overflow valve 14 and the opening of the flow regulating valve 8, respectively. The electromagnetic overflow valve 14 and the accumulator 15 control the pressure of the drug injection system, and in conjunction with the opening of the flow regulating valve 8, jointly control the drug injection flow rate. The injected drug solution and water solvent are mixed by the static mixing device 18, and after mixing, the solution is sprayed through the nozzle 22, completing the direct injection online mixing process.

[0120] This direct-injection online pesticide and fertilizer mixing system uses a water solvent flow transmitter 5 and a pesticide flow transmitter 7 to monitor in real time whether the flow rates of the water solvent entering the static pesticide and fertilizer mixing unit 18 match the pesticide injection flow rate. It also uses a first conductivity transmitter 17 and a second conductivity transmitter 19 to monitor the mixing uniformity in real time, enabling real-time adjustment of the mixing ratio and monitoring of mixing uniformity. A level sensor collects the level information of the water tank 3 and the pesticide tank 13. When the level falls below the system's preset value, an alarm is triggered, reminding the operator to add water solvent or pesticide.

[0121] Figure 15 This is a direct injection online mixing system for pesticides and fertilizers according to another preferred embodiment of the present invention. This preferred embodiment is... Figure 5 The implementation methods shown are largely the same, except that the overflow valve 4 is replaced by a bypass reflux regulating valve 24 connected to the controller 23. The controller 23 can control the injection flow rate of the water solvent by controlling the opening of the bypass reflux regulating valve 24. The water solvent flow rate can be finely adjusted according to the real-time drug injection flow rate and the target mixing ratio information, so as to ensure that the real-time mixing ratio is consistent with the target mixing ratio as much as possible.

[0122] The static pesticide and fertilizer mixer and the direct injection online pesticide and fertilizer mixing system of the present invention can be used in agricultural machinery such as agricultural plant protection machinery.

[0123] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention. For example, the plunger pump 2 and diaphragm pump 11 described above can be selected as other types of pumps, and various specific technical features can be combined in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A static pesticide and fertilizer mixer, characterized in that, include: The mixing device housing (100) has an injection port (110) and an outlet (120) at its two axial ends respectively. Multiple sets of mixing units (200) are arranged axially spaced within the mixing unit housing (100). Each set of mixing units (200) includes a first baffle group and a second baffle group arranged opposite to each other and respectively attached to the inner wall surface of the mixing unit housing (100). The first baffle group and the second baffle group each have multiple inclined baffles (210) arranged axially spaced and each having multiple flow holes (220). The inclined baffles (210) of the first baffle group and the second baffle group are inclined relative to the axial direction of the mixing unit housing (100) in opposite directions. The tilt angle α of the inclined baffle (210) relative to the axial direction of the mixer housing (100) is 50°-60°, and the distance L between adjacent mixing units (200) is 10mm-23mm.

2. The static pesticide and fertilizer mixer according to claim 1, characterized in that, Multiple sets of the mixing units (200) are connected as one unit by multiple connecting rods (300) extending axially parallel to the mixing device housing (100).

3. The static pesticide and fertilizer mixer according to claim 1, characterized in that, The static mixing device includes three sets of mixing units (200) arranged axially spaced apart from each other within the mixing device housing (100), and the first and second baffle groups in each set of mixing units (200) are arranged in phase within the mixing device housing (100), and / or, the first and second baffle groups each have four inclined baffles (210) arranged axially at equal intervals and parallel to each other.

4. The static pesticide and fertilizer mixer according to claim 1, characterized in that, The spacing L between adjacent mixing units (200) is 22mm-23mm.

5. The static pesticide and fertilizer mixer according to claim 1, characterized in that, The diameter d of the flow passage (220) is 1mm-2mm.

6. The static pesticide and fertilizer mixer according to claim 5, characterized in that, The diameter d of the flow passage (220) is 1.5mm-1.8mm.

7. A direct injection online mixing system for pesticides and fertilizers, characterized in that, Includes a static mixing device (18) according to any one of claims 1 to 6, as well as a water solvent injection path and a liquid drug injection path, wherein the water solvent injection path and the liquid drug injection path are connected to the injection port (110) through an injection pipeline equipped with a first conductivity transmitter (17), and the discharge port (120) is connected to a discharge pipeline equipped with a second conductivity transmitter (19).

8. The direct injection online mixing system for pesticides and fertilizers according to claim 7, characterized in that, The liquid injection path is provided with a pressure tank (10), a flow regulating valve (8) for regulating the flow rate of the liquid delivered from the pressure tank (10) to the injection pipeline, and an overflow path connecting the pressure tank (10) and the liquid tank (13). The overflow path is provided with an electromagnetic overflow valve (14) and an accumulator (15) for regulating the pressure inside the pressure tank (10).

9. The direct injection online mixing system for pesticides and fertilizers according to claim 8, characterized in that, The injection pipeline is also provided with a first pressure transmitter (16), the liquid injection flow line is provided with a second pressure transmitter (9) for detecting the pressure of the liquid delivered from the pressure tank (10) to the injection pipeline, and / or, the water solvent injection flow line is provided with a water solvent flow transmitter (5), and the liquid injection flow line is provided with a liquid flow transmitter (7).

10. The direct injection online mixing system for pesticides and fertilizers according to claim 8, characterized in that, It also includes a controller (23) that is signal-connected to the first conductivity transmitter (17) and the second conductivity transmitter (19), which is capable of controlling the opening of the flow regulating valve (8) and / or the overflow pressure of the electromagnetic overflow valve (14) according to the detection signals of the first conductivity transmitter (17) and the second conductivity transmitter (19).

11. The direct injection online mixing system for pesticides and fertilizers according to claim 7, characterized in that, The end of the discharge pipe away from the static mixing and fertilizer mixer (18) is connected to a liquid spray bar, which is equipped with multiple nozzles (22).

12. An agricultural machine, characterized in that, The agricultural machinery includes a static pesticide and fertilizer mixer (18) according to any one of claims 1 to 6 or a direct injection online pesticide and fertilizer mixing system according to any one of claims 7 to 11.

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