A dynamic filtering and adjusting system based on a water and fertilizer integrated device

Abstract

The application provides a dynamic filtering adjustment system based on a water and fertilizer integrated device, which comprises a water and fertilizer mixing barrel, a fertilizer injection pipe, a fertilizer conveying pump, a centrifugal filter and an automatic backwashing screen filter, and a variable frequency motor is connected to the automatic backwashing screen filter; the system further comprises a control assembly, which comprises a controller, a temperature sensor arranged at a water inlet pipe and used for detecting water temperature, a differential pressure transmitter used for detecting a pressure difference between an inlet and an outlet of the automatic backwashing screen filter, and a turbine flowmeter used for detecting a real-time flow rate of the fertilizer conveying pump; the controller calculates a basic filtering precision based on an outlet pressure difference collected by the differential pressure transmitter, calculates a correction coefficient based on the detected water temperature and the flow rate of the fertilizer conveying pump, calculates a final filtering precision based on the calculated basic filtering precision and the correction coefficient, and controls the variable frequency motor to adjust the filtering precision thereof to the final filtering precision.

Description

Technical Field

[0001] This invention relates to the field of integrated water and fertilizer systems, and more specifically, to a dynamic filtration and regulation system based on an integrated water and fertilizer system. Background Technology

[0002] According to a study in the Transactions of the Chinese Society of Agricultural Engineering (2021), the pretreatment of granular fertilizer accounts for more than 35% of the overall fertilization operation time, which greatly affects the efficiency of the entire water and fertilizer irrigation process. Insufficient dissolution time can lead to incomplete dissolution, and incompletely dissolved granules can clog drip irrigation tape, causing localized seedling burn or fertilization gaps. A survey by the Chinese Academy of Agricultural Sciences shows that the unevenness of traditional granular fertilizer application is as high as ±25%, severely restricting fertilizer effectiveness. For example, a water and fertilizer integrated irrigation device disclosed in announcement number CN115299235A includes: a mobile base, a water and fertilizer mixing device, a pressing grinding device, a double-axis scissor telescopic device, and a control system; it can automatically pick up materials and water, grind fertilizer granules before dissolving them in water, improving dissolution efficiency and fertilizer utilization, thus achieving water and fertilizer integration. Although this device uses the measure of grinding and crushing granular fertilizer before dissolving it in water to improve dissolution efficiency, it does not precisely control the water temperature during dissolution, keeping the water temperature between 30-50℃. The existing equipment allows most water-soluble fertilizers, such as potassium nitrate and potassium dihydrogen phosphate, to dissolve most quickly. However, dissolving fertilizers directly with pumped water is affected by changes in ambient temperature, which can affect the actual dissolution rate. This makes it difficult for operators to accurately determine whether the fertilizer has completely dissolved. In addition, the existing equipment is designed for a relatively limited range of fertilizer types and has a filtration structure for the water used to prepare the fertilizer solution. However, a single filtration method cannot achieve thorough filtration of the water. If a filtration structure with a smaller pore size is used, the fixed pore diameter makes it impossible to adjust the filtration according to different water quality conditions, thus failing to achieve dynamic filtration adjustment of the water. Summary of the Invention

[0003] The main objective of this application is to provide a dynamic filtration and regulation system based on an integrated water and fertilizer device to solve the problems of low efficiency in dissolving granular fertilizers and inability to achieve dynamic filtration and regulation of water bodies in existing devices.

[0004] To achieve the above objectives, in a first aspect, this application provides a dynamic filtration and adjustment system based on an integrated water and fertilizer device, including a water and fertilizer mixing tank, a fertilizer injection pipe connected to the water and fertilizer mixing tank, a fertilizer delivery pump connected to the fertilizer injection pipe, a centrifugal filter connected to an inlet pipe, and an automatic backwashing mesh filter connected to the centrifugal filter via a connecting pipe. The fertilizer injection pipe is connected to the connecting pipe, the automatic backwashing mesh filter is connected to a fertilizer application pipe, and a variable frequency motor for adjusting its filtration accuracy is connected to the automatic backwashing mesh filter. It also includes a control component, which includes a controller, a temperature sensor installed at the inlet pipe for detecting water temperature, a differential pressure transmitter for detecting the pressure difference between the inlet and outlet of the automatic backwash mesh filter, and a turbine flow meter for detecting the real-time flow rate of the fertilizer delivery pump. The controller calculates the basic filtration accuracy based on the outlet pressure difference collected by the differential pressure transmitter, calculates a correction coefficient based on the detected water temperature and the flow rate of the fertilizer delivery pump, and calculates the final filtration accuracy based on the calculated basic filtration accuracy and the correction coefficient. The controller controls the variable frequency motor to adjust its filtration accuracy to the final filtration accuracy.

[0005] Optionally, the basic filtration accuracy M1 = M min ×(M max -M min ),in, For the export pressure differential, min is the minimum differential pressure value of the automatic backwashing mesh filter. `max` represents the maximum differential pressure of the automatic backwashing mesh filter. min For the minimum filtration accuracy of an automatic backwashing mesh filter, M max This represents the maximum filtration accuracy of the automatic backwashing mesh filter.

[0006] Optionally, the correction coefficient Where K1 is the water temperature correction coefficient and K2 is the fertilizer injection flow rate correction coefficient.

[0007] Optionally, the water temperature detected by the temperature sensor is T. When T is less than 20℃, K1=1.3; when T is greater than or equal to 20℃ and less than 30℃, K1=1.1; when T is greater than or equal to 30℃ and less than 50℃, K1=1.0; and when T is greater than or equal to 50℃, K1=0.9.

[0008] Optionally, fertilizer injection flow rate correction factor , where V is the real-time flow rate of the fertilizer delivery pump being detected.

[0009] Optionally, the final filtration accuracy .

[0010] Optionally, the controller controls the variable frequency motor through PID regulation.

[0011] Optionally, Where U(t) is the motor adjustment amount, K p K is the proportionality coefficient. i K is the integral coefficient. d The differential coefficient is e(t) = M2 - M, where M is the actual accuracy of the current automatic backwashing mesh filter.

[0012] Optionally, K p =0.8, K i =0.2, Kd=0.1.

[0013] Optionally, the precision adjustment range of the automatic backwashing mesh filter is 60-180 mesh.

[0014] The present invention provides a dynamic filtration adjustment system based on an integrated water and fertilizer device. Compared with the prior art, its advantages are as follows: The present invention focuses on three core parameters: water temperature, fertilizer injection flow rate, and filter pressure difference, and realizes intelligent and dynamic control of filtration accuracy. Based on pressure difference and with water temperature and fertilizer injection flow rate as correction factors, the filtration accuracy is dynamically adjusted according to the working conditions through linear mapping and dual-factor correction. This ensures effective filtration of impurities in the water and fertilizer mixture, avoids efficiency reduction caused by over-filtration, reduces problems such as drip irrigation tape blockage and seedling burn, and improves the stability of water and fertilizer supply. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a schematic diagram of the present invention.

[0016] The components include: 1. Water and fertilizer mixing tank; 2. Fertilizer injection pipe; 3. Fertilizer delivery pump; 4. Centrifugal filter; 5. Automatic backwashing mesh filter; 6. Fertilizer application pipe; 7. Variable frequency motor. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0020] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0021] In addition, the term "multiple" should mean two or more.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] like Figure 1 As shown, a dynamic filtration and adjustment system based on an integrated water and fertilizer device includes a water and fertilizer mixing tank 1, a fertilizer injection pipe 2 connected to the water and fertilizer mixing tank 1, a fertilizer delivery pump 3 connected to the fertilizer injection pipe 2, a centrifugal filter 4 connected to an inlet pipe, and an automatic backwashing mesh filter 5 connected to the centrifugal filter 4 via a connecting pipe. The fertilizer injection pipe 2 is connected to the connecting pipe, the automatic backwashing mesh filter 5 is connected to a fertilizer application pipe 6, and a variable frequency motor 7 is connected to the automatic backwashing mesh filter 5 to adjust its filtration accuracy. It also includes a control component, which includes a controller, a temperature sensor installed at the inlet pipe for detecting water temperature, a differential pressure transmitter for detecting the pressure difference between the inlet and outlet of the automatic backwash mesh filter 5, and a turbine flow meter for detecting the real-time flow rate of the fertilizer delivery pump 3. The controller calculates the basic filtration accuracy based on the outlet pressure difference collected by the differential pressure transmitter, calculates the correction coefficient based on the detected water temperature and the flow rate of the fertilizer delivery pump 3, and calculates the final filtration accuracy based on the calculated basic filtration accuracy and the correction coefficient. The controller controls the variable frequency motor 7 to adjust its filtration accuracy to the final filtration accuracy.

[0024] Optionally, the basic filtration accuracy M1 = M min ×(M max -M min ),in, For the export pressure differential, `min` represents the minimum differential pressure of the automatic backwashing mesh filter, preferably 0.1. `max` represents the maximum differential pressure of the automatic backwashing mesh filter, preferably 0.2. min For the minimum filtration accuracy of an automatic backwashing mesh filter, M max To achieve the maximum filtration accuracy of the automatic backwashing mesh filter, M in this embodiment... min For 60, M max It is 180.

[0025] The correction coefficient Where K1 is the water temperature correction coefficient and K2 is the fertilizer injection flow rate correction coefficient.

[0026] The water temperature detected by the temperature sensor is T. When T is less than 20℃, K1=1.3; when T is greater than or equal to 20℃ and less than 30℃, K1=1.1; when T is greater than or equal to 30℃ and less than 50℃, K1=1.0; and when T is greater than or equal to 50℃, K1=0.9.

[0027] Fertilizer Injection Flow Rate Correction Coefficient , where V is the real-time flow rate of the fertilizer delivery pump being detected.

[0028] The final filtration accuracy .

[0029] Ultimately, the controller controls the variable frequency motor through PID regulation.

[0030] Specifically, Where U(t) is the motor adjustment amount, K p K is the proportionality coefficient. i K is the integral coefficient. dThe differential coefficient is e(t) = M² - M, where M is the actual accuracy of the current automatic backwashing mesh filter, and K is the differential coefficient. p =0.8, K i =0.2, Kd=0.1.

[0031] The specific structure of the precision adjustment structure of the automatic backwashing mesh filter 5 is not the design focus of this invention. It can be achieved by setting a first fixed filter screen plate and a second rotating filter screen plate, and driving the second rotating filter screen plate to rotate by a variable frequency motor, thereby adjusting the size of the filter holes formed between the first filter screen plate and the second filter screen plate, thereby realizing the adjustment of filtration precision.

[0032] The core design principle of the above solution is based on the pressure difference (ΔP) between the inlet and outlet of the automatic backwash mesh filter. The water source temperature (T) and the real-time flow rate (V) of the fertilizer injection pump are used as dual correction factors. The pressure difference signal is converted into basic filtration accuracy through a linear mapping algorithm. After dual-factor collaborative correction, the filtration accuracy is dynamically and adaptively adjusted according to the working conditions. The core goal of effective impurity filtration, optimal filtration efficiency, and stable water and fertilizer supply is achieved, which fundamentally solves the pain points of traditional fixed-precision filtration such as clogging, over-filtration, and fertilizer loss.

[0033] The core logic of this invention can be summarized as follows: using the filter pressure difference to reflect the degree of impurity blockage as the basis for adjusting the filtration accuracy; using water temperature to reflect fertilizer dissolution efficiency and fertilizer injection flow rate to reflect the impurity input rate as the basis for dynamic correction of filtration accuracy; converting the pressure difference signal into an executable basic filtration accuracy through linear mapping, and then dynamically calibrating the basic accuracy through a two-factor correction coefficient, finally outputting the optimal filtration accuracy (M2) adapted to the current working conditions; at the same time, improving the versatility of the solution through parameterized design, ensuring that the filtration accuracy meets the impurity filtration requirements while avoiding efficiency reduction caused by over-filtration, thus achieving a balance between filtration performance and operating efficiency.

[0034] The pressure difference (ΔP) between the filter inlet and outlet is a core indicator reflecting the degree of filter clogging and the content of impurities in the water. It is also the basis for adjusting the filtration accuracy in this scheme. Its adjustment principle is based on the engineering logic that "pressure difference is positively correlated with impurity content and impurity content is positively correlated with filtration accuracy requirements". Through linear normalization mapping, the pressure difference signal is converted into the basic filtration accuracy (M1).

[0035] From a principle perspective, the filter screen of an automatic backwashing mesh filter is the core component for impurity interception. When impurities in the water (including undissolved fertilizer particles, suspended solids in the water source, etc.) pass through the filter screen, they gradually adhere to the screen, causing a decrease in the screen's permeability. This, in turn, creates a pressure difference between the filter's inlet and outlet: the smaller the pressure difference, the lower the degree of filter screen clogging and the lower the impurity content in the water, and the lower the required filtration precision; the larger the pressure difference, the higher the degree of filter screen clogging and the higher the impurity content in the water, and the higher the required filtration precision.

[0036] To achieve a precise correspondence between pressure difference and filtration accuracy, this solution employs a linear normalization mapping algorithm, deriving the basic filtration accuracy calculation formula: M1 = 60 + [(ΔP - 0.01) / (0.2 - 0.01)]×(Mmax ​​- 60). Where 0.01MPa is the minimum pressure difference (ΔPmin) when the filter is unclogged, at which point the water is cleanest, corresponding to a minimum filtration accuracy of 60 mesh (Mmin); 0.2MPa is the maximum pressure difference (ΔPmax) when the filter is close to clogging, at which point the impurity content is highest, corresponding to the equipment's maximum filtration accuracy Mmax (default 180 mesh); (ΔP - 0.01) / (0.2 - 0.01) is the pressure difference normalization ratio, reflecting the current pressure difference's position within the "unclogging - extreme clogging" range. Multiplying this ratio by the filtration accuracy adjustment range (Mmax ​​- 60), and then adding the minimum filtration accuracy of 60 mesh, yields the basic filtration accuracy M1 corresponding to the current pressure difference.

[0037] The basic filtration accuracy (M1) is determined solely based on pressure difference and does not consider the dynamic changes in the operating conditions of the water and fertilizer system. However, water temperature (T) and fertilizer injection flow rate (V) are key factors affecting impurity content and filtration requirements, directly determining the adaptability of the filtration accuracy. Therefore, this solution introduces dual correction factors (K1: water temperature correction coefficient, K2: fertilizer injection flow rate correction coefficient). Through the comprehensive correction of K=K1×K2, the basic accuracy M1 is calibrated, and the optimal filtration accuracy M2 is finally obtained, realizing the dynamic adaptation of filtration accuracy to operating conditions.

[0038] The core principle of water temperature correction is that "water temperature affects fertilizer dissolution efficiency, which in turn affects impurity content, and consequently affects the required filtration precision." The dissolution rate of fertilizers (especially granular fertilizers) is positively correlated with water temperature. The higher the water temperature, the more fully the fertilizer dissolves, the fewer undissolved particulate impurities remain, and the lower the required filtration precision. Conversely, the lower the water temperature, the less fully the fertilizer dissolves, the more undissolved particulate impurities remain, and the higher the required filtration precision. If the filtration precision is insufficient, undissolved particulate impurities can clog the filter screen and drip irrigation tape, and may even cause localized seedling burn.

[0039] Based on the above principles, this invention sets a water temperature correction coefficient K1 by determining the range. The specific logic is as follows: when T < 20℃, the fertilizer dissolution efficiency is extremely low, and there are a lot of undissolved particles, so the filtration precision needs to be greatly improved, and K1 = 1.3 is set; when 20℃ ≤ T < 30℃, the fertilizer dissolution efficiency is average, and there are a few undissolved particles, so the filtration precision needs to be moderately improved, and K1 = 1.1 is set; when 30℃ ≤ T ≤ 50℃, the fertilizer dissolution efficiency is optimal, and there are the fewest undissolved particles, so there is no need to improve the filtration precision, and K1 = 1.0 is set; when T > 50℃, the fertilizer dissolution efficiency is too high, and fertilizer crystallization may occur, so the filtration precision needs to be moderately reduced to avoid excessive filtration affecting the water and fertilizer supply efficiency, and K1 = 0.9 is set.

[0040] The core principle of fertilizer injection flow rate correction is that "the fertilizer injection flow rate reflects the rate of impurity input, which affects the filter screen load and thus the required filtration accuracy." The higher the real-time flow rate (V) of the fertilizer injection pump, the greater the flow rate of the water-fertilizer mixture injected per unit time, the more fertilizer particles and impurities it carries, and the greater the impurity interception load on the filter screen. If the filtration accuracy is insufficient, impurities will quickly adhere to the filter screen, causing filter screen blockage, a sudden increase in pressure difference, and affecting the stable operation of the system. The lower the fertilizer injection flow rate, the less impurities are input per unit time, the smaller the filter screen load, and the lower the required filtration accuracy. The accuracy can be appropriately reduced to improve filtration efficiency.

[0041] Based on the above principles, this scheme sets the fertilizer injection flow rate correction coefficient K2 through linear calculation. The calculation formula is: K2 = 1 + (V / 50) × 0.3. Where 50 L / min is the maximum rated flow rate of the fertilizer injection pump (Vmax), 0.3 is the maximum correction range, and V is the real-time fertilizer injection flow rate. When V = 0, no fertilizer is injected, the impurity input rate is 0, K2 = 1.0, and no correction is needed. When V = 50 L / min, the impurity input rate is at its maximum, K2 = 1.3, requiring a maximum increase in filtration accuracy. When V is between 0 and 50 L / min, K2 increases linearly with the increase of V, achieving synchronous adaptation between filtration accuracy and fertilizer injection flow rate.

[0042] The comprehensive correction coefficient K = K1 × K2 is based on the principle of superimposing the effects of water temperature and fertilizer injection flow rate to accurately calibrate the basic filtration accuracy M1, ultimately outputting the optimal filtration accuracy M2. The calculation formula is: M2 = min[round(M1 × K1 × K2), Mmax]. Here, the round() function rounds the calculation result (filtration accuracy must be an integer), and the min() function limits M2 to not exceeding the device's maximum filtration accuracy Mmax, avoiding exceeding the device's hardware capabilities.

[0043] Compared to traditional fixed-precision filtration, its core advantages lie in "dynamic adaptation, precision and efficiency, and versatility and flexibility." Its advantages at the principle level can be summarized in three points: First, based on pressure difference, it accurately captures the filter's clogging status and impurity content, achieving a fundamental determination of filtration precision and ensuring the effectiveness of impurity interception. Second, using water temperature and fertilizer injection flow rate as dual correction factors, it dynamically adapts to fertilizer dissolution conditions and impurity input rates, avoiding over-filtration and under-filtration, achieving a balance between filtration efficiency and effect. Third, through parameterized design and closed-loop linkage, it improves the versatility and stability of the solution, adapting to different models of mesh filters while achieving seamless collaboration with integrated water and fertilizer systems, reducing equipment failures, ensuring stable water and fertilizer supply, and providing reliable water and fertilizer support for crop growth.

[0044] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A dynamic filtration and regulation system based on an integrated water and fertilizer device, characterized in that, The system includes a water-fertilizer mixing tank, a fertilizer injection pipe connected to the water-fertilizer mixing tank, a fertilizer delivery pump connected to the fertilizer injection pipe, a centrifugal filter connected to an inlet pipe, and an automatic backwashing mesh filter connected to the centrifugal filter via a connecting pipe. The fertilizer injection pipe is connected to the connecting pipe, the automatic backwashing mesh filter is connected to a fertilizer application pipe, and the automatic backwashing mesh filter is connected to a variable frequency motor for adjusting its filtration accuracy. It also includes a control component, which includes a controller, a temperature sensor installed at the inlet pipe for detecting water temperature, a differential pressure transmitter for detecting the pressure difference between the inlet and outlet of the automatic backwash mesh filter, and a turbine flow meter for detecting the real-time flow rate of the fertilizer delivery pump. The controller calculates the basic filtration accuracy based on the outlet pressure difference collected by the differential pressure transmitter, calculates a correction coefficient based on the detected water temperature and the flow rate of the fertilizer delivery pump, and calculates the final filtration accuracy based on the calculated basic filtration accuracy and the correction coefficient. The controller controls the variable frequency motor to adjust its filtration accuracy to the final filtration accuracy. The basic filtration accuracy M1=M min ×(M max -M min ),in, For the inlet and outlet pressure difference of the automatic backwashing mesh filter, min is the minimum differential pressure value of the automatic backwashing mesh filter. `max` represents the maximum differential pressure of the automatic backwashing mesh filter. min For the minimum filtration accuracy of an automatic backwashing mesh filter, M max This represents the maximum filtration accuracy of the automatic backwashing mesh filter. The correction coefficient Where K1 is the water temperature correction coefficient and K2 is the fertilizer injection flow rate correction coefficient; The water temperature detected by the temperature sensor is T. When T is less than 20℃, K1=1.3; when T is greater than or equal to 20℃ and less than 30℃, K1=1.1; when T is greater than or equal to 30℃ and less than 50℃, K1=1.0; when T is greater than or equal to 50℃, K1=0.

9. Fertilizer Injection Flow Rate Correction Coefficient , where V is the real-time flow rate of the fertilizer delivery pump being detected; The final filtration accuracy ; The precision adjustment range of the automatic backwashing mesh filter is 60-180 mesh.

2. The dynamic filtration and adjustment system based on an integrated water and fertilizer device as described in claim 1, characterized in that: The controller controls the variable frequency motor through PID regulation.

3. The dynamic filtration and adjustment system based on an integrated water and fertilizer device as described in claim 2, characterized in that: Where U(t) is the motor adjustment amount, K p K is the proportionality coefficient. i K is the integral coefficient. d The differential coefficient is e(t) = M2 - M, where M is the actual accuracy of the current automatic backwashing mesh filter.

4. The dynamic filtration and adjustment system based on an integrated water and fertilizer device as described in claim 3, characterized in that: K p =0.8,K i =0.2,K d =0.1。

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