CN114600760B - Nutrient solution return irrigation regulation method and nutrient solution circulation system - Google Patents
Nutrient solution return irrigation regulation method and nutrient solution circulation system Download PDFInfo
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- CN114600760B CN114600760B CN202210254376.XA CN202210254376A CN114600760B CN 114600760 B CN114600760 B CN 114600760B CN 202210254376 A CN202210254376 A CN 202210254376A CN 114600760 B CN114600760 B CN 114600760B
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
- A01G31/00—Soilless cultivation, e.g. hydroponics
- A01G31/02—Special apparatus therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D36/00—Filter circuits or combinations of filters with other separating devices
- B01D36/02—Combinations of filters of different kinds
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P60/00—Technologies relating to agriculture, livestock or agroalimentary industries
- Y02P60/20—Reduction of greenhouse gas [GHG] emissions in agriculture, e.g. CO2
- Y02P60/21—Dinitrogen oxide [N2O], e.g. using aquaponics, hydroponics or efficiency measures
Abstract
The invention provides a nutrient solution liquid return irrigation regulation method and a nutrient solution circulation system, which comprise the steps of determining the liquid level of a liquid return tank reaching the standard, the liquid outlet flow of the liquid return tank reaching the standard, the liquid inlet flow of a liquid fertilizer machine or determining the liquid inlet EC value of the liquid fertilizer machine; the liquid level of the standard-reaching liquid returning tank is larger than a second preset liquid level, and when the ratio of the liquid flow of the standard-reaching liquid returning tank to the liquid flow of the liquid inlet of the liquid fertilizer machine is larger than or smaller than a first preset range or the EC value of the liquid inlet of the liquid fertilizer machine is larger than or smaller than a first preset EC value, the liquid flow of the standard-reaching liquid returning tank and the liquid flow of the clear water inlet are regulated; and when the liquid level of the standard-reaching liquid returning tank is larger than the first preset liquid level and smaller than or equal to the second preset liquid level, and the liquid flow of the standard-reaching liquid returning tank is smaller than or larger than a second preset value or the EC value of the liquid inlet of the liquid fertilizer machine is larger than or smaller than the second preset EC value, the liquid flow of the standard-reaching liquid returning tank and the liquid flow of the clear water inlet are regulated. The liquid return of the standard nutrient solution in the standard return tank can meet the liquid return amount required by normal irrigation of the water and fertilizer machine, and the utilization rate of the nutrient solution return of the cultivation system is improved.
Description
Technical Field
The invention relates to the technical field of cultivation facilities, in particular to a nutrient solution return irrigation regulating method and a nutrient solution circulating system.
Background
The facility vegetable soilless culture system mostly adopts an open mode. The soilless culture system is in an open mode, nutrient solution is returned to the natural environment, so that water resources and fertilizer are wasted greatly, and the environment is polluted greatly. Therefore, the closed nutrient solution recycling mode of the soilless culture system is adopted, the nutrient solution is recycled for disinfection, fertilizer and water resources are greatly saved, and environmental pollution is reduced.
The existing closed nutrient solution recycling mode is characterized in that when cultivated crops are subjected to liquid return irrigation, the sterilized nutrient solution return liquid cannot be directly irrigated, so that the standard nutrient solution return liquid and water are required to be mixed to meet the irrigation requirement, but the standard return liquid amount of each return liquid can be different, the irrigation amount of each time for cultivated crops is fixed, when the standard nutrient solution return liquid is less, before the irrigation amount is not reached, the standard nutrient solution can be discharged, and in order to meet the irrigation amount, the standard nutrient solution can be irrigated by clear water only, so that the utilization rate of the standard nutrient solution is lower.
Disclosure of Invention
The invention provides a nutrient solution return irrigation regulation method and a nutrient solution circulation system, which are used for solving the defect of low nutrient solution return utilization rate in a closed nutrient solution circulation utilization mode of the existing soilless culture system.
The invention provides a nutrient solution return irrigation regulation method, which comprises the following steps:
determining the liquid level of a standard-reaching liquid return tank, the liquid outlet flow of the standard-reaching liquid return tank and the liquid inlet flow of a liquid fertilizer machine, wherein the liquid inlet flow of the liquid fertilizer machine is the sum of the liquid outlet flow of the standard-reaching liquid return tank and the liquid inlet flow of clear water, the liquid fertilizer machine is used for preparing and supplying nutrient solution to a cultivation system, and the standard-reaching liquid return tank is used for storing the standard-reaching nutrient solution liquid returned by the cultivation system after being discharged and disinfected;
when the liquid level of the standard-reaching liquid return tank is larger than a second preset liquid level and the ratio of the liquid outlet flow of the standard-reaching liquid return tank to the liquid inlet flow of the liquid and fertilizer machine is larger than or smaller than a first preset range, the liquid outlet flow of the standard-reaching liquid return tank and the liquid inlet flow of clear water are regulated until the ratio of the liquid outlet flow of the standard-reaching liquid return tank to the liquid inlet flow of the liquid and fertilizer machine is within the first preset range;
when the liquid level of the standard-reaching liquid returning tank is larger than the first preset liquid level and smaller than or equal to the second preset liquid level, and the liquid outlet flow of the standard-reaching liquid returning tank is smaller than or larger than the second preset value, regulating the liquid outlet flow of the standard-reaching liquid returning tank and the fresh water inlet flow of the standard-reaching liquid returning tank until the liquid outlet flow of the standard-reaching liquid returning tank is equal to the second preset value;
Or alternatively, the first and second heat exchangers may be,
determining the liquid level of a standard-reaching liquid return tank and the EC value of the liquid inlet of a liquid fertilizer machine, wherein the EC value of the liquid inlet of the liquid fertilizer machine is the EC value of the mixed liquid of the liquid outlet of the standard-reaching liquid return tank and the liquid inlet of clear water;
when the liquid level of the standard-reaching liquid return tank is larger than a second preset liquid level and the EC value of the liquid inlet of the liquid fertilizer machine is larger than or smaller than a first preset EC value, regulating the liquid outlet flow of the standard-reaching liquid return tank and the fresh water inlet flow until the EC value of the liquid inlet of the liquid fertilizer machine is equal to the first preset EC value;
when the liquid level of the standard-reaching liquid return tank is larger than the first preset liquid level and smaller than or equal to the second preset liquid level, and the EC value of the liquid inlet of the liquid fertilizer machine is larger than or smaller than the second preset EC value, the liquid outlet flow of the standard-reaching liquid return tank and the fresh water inlet flow are regulated until the EC value of the liquid inlet of the liquid fertilizer machine is equal to the second preset EC value.
According to the nutrient solution return irrigation regulation method provided by the invention, the first preset range is 0.25-0.3, and the second preset value is V BC T, where V BC For the volume between the first preset liquid level and the second preset liquid level in the standard-reaching liquid return tank, t is the residual irrigation time of the liquid fertilizer machine when the liquid level of the standard-reaching liquid return tank is equal to the second preset liquid level;
or alternatively, the first and second heat exchangers may be,
The first preset EC value is 0.5 time of the nutrient solution EC value of the water and fertilizer machine, and the second preset EC value is 0.3 time of the nutrient solution EC value of the water and fertilizer machine.
The invention provides a nutrient solution return irrigation regulating method, which further comprises the following steps:
determining the liquid level of nutrient solution return in the return tank;
when the liquid level of the nutrient solution return in the return tank is larger than a first liquid level value, controlling the return output pump to start;
when the liquid level of the nutrient solution return in the return tank is smaller than the second liquid level value, controlling the return output pump to stop;
the first liquid level value is larger than the second liquid level value, the liquid return tank is used for storing nutrient solution liquid return discharged by the cultivation system, and the liquid return output pump is used for conveying the nutrient solution liquid return in the cultivation system into the liquid return tank.
The invention provides a nutrient solution return irrigation regulating method, which further comprises the following steps:
determining the working state of a liquid return output pump;
when the liquid level of the standard-reaching liquid returning tank is larger than a third preset liquid level and the liquid returning output pump is in a working state, controlling the liquid fertilizer machine to start irrigation of the cultivation system;
wherein the third preset liquid level is greater than the second preset liquid level.
The invention also provides a nutrient solution circulating system, which is based on the nutrient solution return irrigation regulation method of any one of the above, and comprises a return unit, an irrigation unit and a control unit;
The liquid return unit comprises a standard-reaching liquid return tank, and the standard-reaching liquid return tank is used for storing the sterilized standard-reaching nutrient liquid returned liquid discharged by the cultivation system;
the irrigation unit comprises a first water supply unit, a first proportional regulating valve and a water and fertilizer machine, wherein a first inlet of the first proportional regulating valve is communicated with an outlet of the standard-reaching liquid return tank, a second inlet of the first proportional regulating valve is communicated with the first water supply unit, and an outlet of the first proportional regulating valve is communicated with the water and fertilizer machine;
the control unit comprises a controller and a first liquid level sensor, the first liquid level sensor and the first proportional regulating valve are electrically connected with the controller, and the first liquid level sensor is used for detecting the liquid level of the up-to-standard nutrient solution return liquid in the up-to-standard return liquid tank;
the control unit further comprises a first flowmeter and a second flowmeter, and the first flowmeter and the second flowmeter are electrically connected with the controller; the first flowmeter is arranged between the first inlet of the first proportional regulating valve and the standard-reaching liquid return tank, and the second flowmeter is arranged between the outlet of the first proportional regulating valve and the water and fertilizer machine;
or, the control unit further comprises an EC sensor, and the EC sensor is electrically connected with the controller; the EC sensor is arranged between the first proportional regulating valve and the water and fertilizer machine.
According to the nutrient solution circulating system provided by the invention, the liquid return unit further comprises:
the liquid return device is used for collecting nutrient liquid return liquid of the cultivation system;
the filtering device is used for filtering the nutrient solution return liquid, and an inlet of the filtering device is communicated with the nutrient solution return device;
the sterilizing device is used for sterilizing and disinfecting the filtered nutrient solution, the inlet of the sterilizing device is communicated with the outlet of the filtering device, and the outlet of the sterilizing device is communicated with the standard-reaching liquid return tank.
The nutrient solution circulating system provided by the invention further comprises a second water supply unit and a turbidity sensor for detecting the turbidity of the filtered nutrient solution;
the device comprises a filter device, a disinfection device, a first proportional control valve, a turbidity sensor, a controller, a second proportional control valve, a second water supply unit, a second proportional control valve, a first inlet of the second proportional control valve, a second water supply unit and a turbidity sensor.
The nutrient solution circulating system provided by the invention further comprises:
the outlet of the first liquid return circuit is communicated with the liquid return device;
the inlet of the first liquid return circuit is communicated with the outlet of the disinfection device through the first valve;
a second valve through which the first inlet of the first proportional control valve can communicate with the outlet of the sterilizing device;
the detection sensor is used for detecting whether the nutrient solution returns to the liquid and disinfects to reach the standard, and the first valve, the second valve and the detection sensor are in communication connection with the controller.
According to the nutrient solution circulation system provided by the invention, the liquid return device comprises:
the liquid return tank is used for collecting nutrient solution return liquid of the cultivation system;
the liquid return tank is used for storing nutrient solution return liquid, and an outlet of the liquid return tank is communicated with an inlet of the filtering device;
the second liquid level sensor is used for monitoring the liquid level of the nutrient solution return liquid in the return liquid tank;
the liquid return output pump is characterized in that an inlet of the liquid return output pump is communicated with an outlet of the liquid return tank, an outlet of the liquid return output pump is communicated with an inlet of the liquid return tank, and the liquid return output pump, the second liquid level sensor and the controller are in communication connection.
According to the present invention, there is provided a nutrient solution circulation system, the filtering device comprising:
the inlet of the sand filter is communicated with the outlet of the liquid return device;
and the inlet of the laminated filter is communicated with the outlet of the sand filter, and the outlet of the laminated filter can be communicated with the inlet of the disinfection device.
According to the nutrient solution return irrigation regulation method and the nutrient solution circulation system, the liquid level in the standard return tank, the liquid outlet flow of the standard return tank and the liquid inlet flow of the liquid fertilizer machine are monitored, or the liquid outlet flow of the standard return tank and the liquid inlet flow of clear water are regulated in real time by monitoring the liquid level in the standard return tank and the EC value of the liquid inlet of the liquid fertilizer machine, so that the standard nutrient solution return in the standard return tank can meet the liquid return required by normal irrigation of the liquid fertilizer machine, and the nutrient solution return utilization rate of the cultivation system is improved.
Drawings
In order to more clearly illustrate the invention or the technical solutions of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a nutrient solution circulation system provided by the invention;
FIG. 2 is a diagram showing the connection relation between the first proportional control valve, the water and fertilizer machine and the standard-reaching liquid return tank;
FIG. 3 is a schematic flow chart of a method for regulating liquid return irrigation of a nutrient solution;
fig. 4 is a second schematic flow chart of the method for regulating the liquid-return irrigation of the nutrient solution.
Reference numerals:
1: a cultivation system; 2: a liquid return tank; 3: returning to the liquid pool; 4: a liquid return output pump;
5: a transfer pump; 6: a sand filter; 7: lamination filter; 8: a turbidity sensor;
9: a second proportional control valve; 10: a second clean water inlet pump; 11: a sterilizing device;
12: a first liquid return circuit; 13: a first valve; 14: a second valve;
15: a liquid return tank reaching the standard; 16: an EC sensor; 17: a first clean water inlet pump;
18: a first proportional control valve; 19: a water fertilizer machine; 20: a second liquid return circuit;
181: a valve; 182: two valves.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The nutrient solution return irrigation regulation method and the nutrient solution circulation system of the present invention are described below with reference to fig. 1 to 4.
As shown in fig. 3, the method for regulating the liquid return irrigation of the nutrient solution provided by the invention comprises the following steps:
determining the liquid level of the standard-reaching liquid return tank 15, the liquid outlet flow of the standard-reaching liquid return tank 15 and the liquid inlet flow of the liquid fertilizer machine 19;
when the liquid level of the standard-reaching liquid return tank 15 is larger than a second preset liquid level and the ratio of the liquid outlet flow of the standard-reaching liquid return tank 15 to the liquid inlet flow of the liquid fertilizer machine 19 is larger than or smaller than a first preset range, the liquid outlet flow of the standard-reaching liquid return tank 15 and the fresh water liquid inlet flow are regulated until the ratio of the liquid outlet flow of the standard-reaching liquid return tank 15 to the liquid inlet flow of the liquid fertilizer machine 19 is positioned between the first preset range;
when the liquid level of the standard-reaching liquid returning tank 15 is larger than the first preset liquid level and smaller than or equal to the second preset liquid level, and the liquid outlet flow of the standard-reaching liquid returning tank 15 is smaller than or larger than the second preset value, the liquid outlet flow of the standard-reaching liquid returning tank 15 and the fresh water inlet flow are regulated until the liquid outlet flow of the standard-reaching liquid returning tank 15 is equal to the second preset value.
Wherein, the feed liquor flow of liquid manure machine 19 can be the sum of the liquid outlet flow of up-to-standard liquid return pot 15 and clear water feed liquor flow, and liquid manure machine 19 is used for preparing and supplying nutrient solution to cultivation system 1, and up-to-standard liquid return pot 15 is used for storing the up-to-standard nutrient solution liquid return discharged by cultivation system 1 and after disinfection.
So set up, through the liquid level in the return tank 15 that reaches standard and the play liquid flow of return tank 15 that reaches standard and the feed liquor flow of liquid manure machine 19 are monitored and are adjusted the play liquid flow of return tank 15 that reaches standard and the feed liquor flow of clear water, can make the nutrient solution that reaches standard in the return tank 15 return liquid and satisfy the required return liquid volume of liquid manure machine 19 normal irrigation, improved the utilization ratio of nutrient solution return liquid of cultivation system 1.
In an alternative embodiment, the first preset range may be 0.25-0.3, that is, when the liquid level of the standard-reaching liquid-returning tank 15 is greater than the second preset liquid level, the liquid outlet flow rate and the clean water inlet flow rate of the standard-reaching liquid-returning tank 15 are adjusted, so that the ratio of the liquid outlet flow rate of the standard-reaching liquid-returning tank 15 to the liquid inlet flow rate of the water and fertilizer machine 19 is 0.25-0.3.
In an alternative embodiment, the second preset value may be V BC T, where V BC For the volume between the first preset liquid level and the second preset liquid level in the standard-reaching liquid return tank 15, t is the residual irrigation time of the liquid fertilizer machine 19 when the liquid level of the standard-reaching liquid return tank 15 is equal to the second preset liquid level.
In another embodiment of the present invention, as shown in fig. 4, the nutrient solution return irrigation regulation method includes:
determining the EC value of the liquid level of the liquid return tank 15 reaching the standard and the liquid inlet of the liquid fertilizer machine 19;
When the liquid level of the standard-reaching liquid return tank 15 is larger than a second preset liquid level and the EC value of the inlet liquid of the liquid fertilizer machine 19 is larger than or smaller than a first preset EC value, regulating the liquid outlet flow of the standard-reaching liquid return tank 15 and the fresh water inlet flow until the EC value of the inlet liquid of the liquid fertilizer machine 19 is equal to the first preset EC value;
when the liquid level of the standard-reaching liquid return tank 15 is greater than the first preset liquid level and less than or equal to the second preset liquid level, and the EC value of the inlet liquid of the liquid fertilizer machine 19 is greater than or less than the second preset EC value, the liquid outlet flow rate and the clean water inlet flow rate of the standard-reaching liquid return tank 15 are regulated until the EC value of the inlet liquid of the liquid fertilizer machine 19 is equal to the second preset EC value.
The EC value of the liquid inlet of the liquid fertilizer machine 19 may be the EC value of the mixed liquid of the liquid outlet of the standard-reaching liquid return tank 15 and the fresh water inlet.
So set up, through the EC value to the liquid level in the liquid return jar 15 up to standard and get into the mixed solution in the liquid manure machine 19 monitor and adjust the play liquid flow of liquid return jar 15 up to standard and the feed liquor flow of clear water, can make the nutrient solution return liquid up to standard in the liquid return jar 15 up to standard satisfy the required liquid return volume of liquid manure machine 19 normal irrigation, improved the utilization ratio of nutrient solution return liquid of cultivation system 1.
In an alternative embodiment, the first preset EC value may be a 0.5 times the nutrient solution EC value of the water and fertilizer machine 19 and the second preset EC value may be a 0.3 times the nutrient solution EC value of the water and fertilizer machine 19.
It should be noted that too little nutrient solution return in the cultivation system is easy to cause the crop to suffer from the umbilical rot, too much nutrient solution return is unfavorable for the growth of the root of the crop, wastes fertilizer, increases the subsequent disinfection cost for the nutrient solution return, and just meets the condition that the nutrient solution return is between 20% and 30% when the EC value of the liquid inlet of the liquid fertilizer machine is 0.5 times or 0.3 times of the nutrient solution of the liquid fertilizer machine, thereby not only maximally utilizing the nutrient solution return, but also ensuring the good growth of the crop and reducing the cost.
According to the scheme, the theoretical basis can be corrected according to the following formula.
(liquid return ratio x liquid return EC value)/water and fertilizer machine target EC value = premix EC value/water and fertilizer machine target EC value. The liquid return duty ratio can be measured by a matrix weighing system, the liquid return EC value can be measured by an EC sensor, the target value EC value of the liquid fertilizer machine is fixed, the actual measured liquid return EC value is generally in a fixed interval, and the measured crop (such as tomatoes) growth and quality data in the interval are good. The EC value of the liquid return is between 5.0 and 7.0 (namely, the fixed interval can be 5.0 and 7.0), the target EC value of the liquid fertilizer machine can be set to 3.0ms/cm, the pre-mixed EC value is 1.5ms/cm, and the liquid return ratio can be 0.2 to 0.3.
In an alternative embodiment of the present invention, the nutrient solution return irrigation regulation method further includes:
determining the liquid level of nutrient solution return in the return tank 2;
when the liquid level of the nutrient solution return in the return tank 2 is larger than a first liquid level value, controlling the return output pump 4 to start;
when the liquid level of the nutrient solution in the liquid return tank 2 is smaller than the second liquid level value, the liquid return output pump 4 is controlled to stop.
The liquid return tank 3 is used for storing nutrient solution liquid returned from the cultivation system 1, the liquid return output pump 4 is used for conveying the nutrient solution liquid returned from the cultivation system 1 into the liquid return tank 3, and the first liquid level value is larger than the second liquid level value.
In this way, the liquid return output pump 4 can be automatically controlled according to the liquid level of the nutrient solution in the liquid return tank 2, and no-load operation of the liquid return output pump 4 can be avoided.
It should be noted that, in order to prevent frequent start of the liquid return output pump 4, the rated flow rate of the liquid return output pump 4 may be 5 min/volume of the liquid return tank 3.
In an alternative embodiment, the nutrient solution return irrigation regulation method further comprises:
determining the working state of the liquid return output pump 4;
when the liquid level of the standard reaching liquid returning tank 15 is larger than the third preset liquid level and the liquid returning output pump 4 is in a working state, the liquid fertilizer machine 19 is controlled to start to irrigate the cultivation system 1 for one period.
Wherein the third preset liquid level is greater than the second preset liquid level.
In this way, the standard nutrient solution in the standard return tank 15 can be prevented from overflowing.
The invention also provides a nutrient solution circulating system, which comprises a nutrient solution return irrigation regulating method based on any one of the embodiments, an irrigation unit and a control unit.
Wherein, as shown in fig. 1, the liquid return unit comprises a standard-reaching liquid return tank 15, and the standard-reaching liquid return tank 15 is used for storing the standard-reaching nutrient solution liquid returned by the cultivation system 1 after being discharged and sterilized.
The irrigation unit comprises a first water supply unit, a first proportional regulating valve 18 and a water and fertilizer machine 19, wherein the water and fertilizer machine 19 is used for preparing and supplying nutrient solution to the cultivation system 1, a first inlet of the first proportional regulating valve 18 is communicated with an outlet of the standard-reaching liquid return tank 15, a second inlet of the first proportional regulating valve 18 is communicated with the first water supply unit, an outlet of the first proportional regulating valve 18 is communicated with the water and fertilizer machine 19, and standard-reaching nutrient solution liquid return discharged from the standard-reaching liquid return tank 15 and the first water supply unit are mixed by the first proportional regulating valve 18 and then enter the water and fertilizer machine 19. In this way, the liquid outlet flow rate of the standard-reaching liquid return tank 15 and the fresh water inlet flow rate of the first water supply unit can be adjusted by adjusting the opening sizes of the first inlet and the second inlet of the first proportional regulating valve 18.
Here, the liquid inlet flow rate of the first inlet of the first proportional control valve 18 is the liquid outlet flow rate of the standard-reaching liquid return tank 15. The inlet flow of the second inlet of the first proportional control valve 18 is the inlet flow of the clean water. The first water supply unit comprises a first clean water inlet pump 17, and the water outlet of the first clean water inlet pump 17 is communicated with the second inlet of the first proportional regulating valve 18.
The control unit comprises a controller, a first flowmeter, a second flowmeter and a first liquid level sensor, wherein the first flowmeter, the second flowmeter, the first liquid level sensor and the first proportional regulating valve 18 are electrically connected with the controller, the first flowmeter is arranged between a first inlet of the first proportional regulating valve 18 and the standard-reaching liquid return tank 15, the second flowmeter is arranged between an outlet of the first proportional regulating valve 18 and the liquid fertilizer machine 19, and the first liquid level sensor is arranged in the standard-reaching liquid return tank 15 and used for detecting the liquid level of the standard-reaching nutrient liquid return liquid in the standard-reaching liquid return tank 15.
The controller may adjust the opening sizes of the first inlet and the second inlet of the first proportional adjustment valve 18 according to the detection values of the first liquid level sensor, the first flow meter, and the second flow meter.
Specifically, when the first liquid level sensor detects that the liquid level of the up-to-standard nutrient solution return liquid is greater than a second preset liquid level, the controller obtains flow values of the first flow meter and the second flow meter, judges whether the ratio of the flow values of the first flow meter and the second flow meter is in a first preset range, and if not, adjusts the opening sizes of the first inlet and the second inlet of the first proportional regulating valve 18 until the ratio of the liquid flow rate of the up-to-standard nutrient solution return tank 15 to the liquid inlet flow rate of the water-fertilizer machine 19 is in the first preset range, even if the ratio of the flow values detected by the first flow meter and the second flow meter is in the first preset range. In this way, the stability of the nutrient solution components output by the water-fertilizer machine 19 can be ensured.
When the first liquid level sensor detects that the liquid level of the nutrient solution returning liquid reaching the standard is greater than the first preset liquid level and smaller than or equal to the second preset liquid level, the controller obtains the flow values of the first flowmeter and the second flowmeter and judges whether the flow value of the first flowmeter is V BC And/t, if not, the controller adjusts the opening sizes of the first inlet and the second inlet of the first proportional regulating valve 18 until reaching the standardThe liquid outlet flow of the liquid return tank 15 is V BC T, even if the flow value detected by the first flow meter is V BC And/t. Thus, the nutrient solution returned from the standard-reaching return tank 15 can be made to satisfy the nutrient solution capacity required for normal irrigation.
It should be noted that, as shown in fig. 2, the first proportional control valve 18 may include a first valve 181 and a second valve 182 that are linked, where the outlet flow of the first proportional control valve 18 is the sum of the flows of the first valve 181 and the second valve 182, that is, the outlet flow of the first proportional control valve 18 is constant regardless of the opening of the first valve 181 and the second valve 182, so that the flow of the mixed liquid flowing into the water-fertilizer machine 19 is constant.
The first preset liquid level may be a liquid level stop position C of the standard-reaching liquid return tank 15, the second preset liquid level may be a liquid level adjustment start position B of the standard-reaching liquid return tank 15, and the third preset liquid level may be a liquid level overflow position a of the standard-reaching liquid return tank 15.
Wherein, the nutrient solution liquid volume that reaches standard returns between B, C positions of reach standard return tank 15 is: v (V) BC ＝S×h BC S is the liquid surface area of the liquid return tank 15 reaching the standard, h BC Is the pitch of B, C locations.
The outlet flow Q of the first proportional regulating valve 18 is the flow Q of a valve 181 connected with the standard-reaching liquid return tank 15 1 And a flow rate Q of two valves 182 connected to the first water supply unit 2 The sum, i.e. q=q 1 +Q 2 。
Here, the initial angle (opening) of the one valve 181 is set to θ, and the initial angle of the two valves 182 is set to pi- θ. In the process that the water and fertilizer machine 19 irrigates the cultivation system 1, when the liquid level of the standard-reaching liquid return tank 15 reaches the position B, the controller obtains the time t from the time when the water and fertilizer machine 19 is stopped (namely, the residual working time of the water and fertilizer machine 19 when the liquid level of the standard-reaching liquid return tank 15 reaches the second preset liquid level).
In order to ensure that the utilization rate of the nutrient solution returns to the maximum, the Q needs to be ensured 1 X t is less than or equal to V BC . In this way, the nutrient solution return liquid can be ensured to be mixed in the whole irrigation process of the water fertilizer machine 19.
Specifically, the standard of the return tank 15 can be presetThe time for returning the nutrient solution reaching the standard from the position B to the position C is t 1 Wherein, the method comprises the steps of, wherein,
V BC ＝Q 1 ×t 1 ，Q 1 ＝θ×Q/π，Q 2 ＝(π-θ)×Q/π。
when t 1 >At t, the controller can maximize nutrient solution return utilization without adjusting the opening of the first proportional control valve 18.
When t 1 <At t, if the opening of the first proportional regulating valve 18 is not regulated at this time, before the irrigation of the water and fertilizer machine 19 is stopped, the standard nutrient solution in the standard return tank 15 is completely utilized (i.e. the liquid level of the standard nutrient solution reaches the position C or below), and at t-t 1 In the (2) time, a valve 181 does not have nutrient solution return liquid to enter, and the outlet of the first proportional regulating valve 18 can only convey clear water to the water and fertilizer machine 19, so that the water and fertilizer machine 19 can realize the following conditions of t-t 1 Only fresh water or nutrient solution with a low EC value can be supplied to the cultivation system 1 in the period of time, so that the utilization rate of the nutrient solution return is reduced, and maximization or optimization cannot be achieved. Therefore, in order to increase the utilization rate of the nutrient solution, the controller can control a valve 181 to gradually close at an angular velocity of ω, for t 1 Is closed exactly for time one valve 181, where ω=θ/t 1 。
Wherein, in the process that the opening of the valve 181 gradually decreases at the angular velocity of omega, the volume of the up-to-standard nutrient solution flowing through the valve 181 is V 1 ＝Q 1 ×t 1 /2。
If V BC Greater than or equal to V 1 At this angular velocity, the controller may control a valve 181 to achieve ω=θ/t, indicating that the liquid level in the standard return tank 15 will not fall below the C position at the end of the operation of the machine 19 1 Gradually closing the angular velocity of (c).
If V BC Less than V 1 It is indicated that at this angular velocity the liquid level in the standard return tank 15 will be below the C position at the end of the operation of the machine 19, whereas in order to ensure that the liquid level in the standard return tank 15 is above or at the C position at the end of the operation of the machine 19, the controller may control a valve 181 to be gradually closed at an angular velocity of w'.
Here, w' =2θ/t 1 -2πV BC /t 1 2 Q；
Wherein, the liquid crystal display device comprises a liquid crystal display device,
in another alternative embodiment of the present invention, the control unit includes a controller, an EC sensor 16 and a first liquid level sensor, where the EC sensor 16, the first liquid level sensor and the first proportional control valve 18 are electrically connected to the controller, the EC sensor 16 is disposed between the first proportional control valve 18 and the water and fertilizer machine 19, and the EC sensor 16 is used to detect an EC value of a liquid inlet of the water and fertilizer machine 19, that is, the EC value of a mixed liquid of a standard nutrient solution return liquid and a clear water inlet is detected by the EC sensor 16; the first liquid level sensor is used for detecting the liquid level of the standard nutrient solution return liquid in the standard return liquid tank 15.
The controller may adjust the opening sizes of the first inlet and the second inlet of the first proportional control valve 18 according to the detection values of the EC sensor 16 and the first liquid level sensor.
Specifically, when the first liquid level sensor detects that the liquid returning of the up-to-standard nutrient solution is greater than the second preset liquid level, the controller obtains the EC value detected by the EC sensor 16 and judges whether the detected EC value is within the first preset EC value, if not, the controller adjusts the opening sizes of the first inlet and the second inlet of the first proportional regulating valve 18 until the EC value of the liquid entering the liquid fertilizer machine 19 is the first preset EC value, even if the EC value of the mixed liquid at the outlet of the first proportional regulating valve 18 is the first preset EC value. In this way, the stability of the nutrient solution components output by the water-fertilizer machine 19 can be ensured.
When the first liquid level sensor detects that the liquid level of the up-to-standard nutrient solution returns is greater than the first preset liquid level and smaller than or equal to the second preset liquid level, the controller obtains the EC value detected by the EC sensor 16 and judges whether the detected EC value is the second preset EC value, if not, the controller adjusts the opening sizes of the first inlet and the second inlet of the first proportional control valve 18 until the EC value of the liquid inlet of the liquid fertilizer machine 19 is the second preset EC value, and even if the EC value of the mixed liquid at the outlet of the first proportional control valve 18 is the second preset EC value. Thus, the nutrient solution returned from the standard-reaching return tank 15 can be made to satisfy the nutrient solution capacity required for normal irrigation.
In an alternative embodiment, when the first liquid level sensor detects that the liquid level of the up-to-standard nutrient solution return is greater than the second preset liquid level, the EC value of the nutrient solution return at the outlet of the first proportional adjustment valve 18 may be 0.5 times the EC value of the nutrient solution of the water and fertilizer machine 19, that is, the opening degrees of the first inlet and the second inlet of the first proportional adjustment valve 18 are adjusted, so that the EC value detected by the EC sensor 16 is 0.5 times the EC value of the nutrient solution of the water and fertilizer machine 19.
When the first liquid level sensor detects that the liquid level of the up-to-standard nutrient solution returning liquid is greater than the first preset liquid level and smaller than or equal to the second preset liquid level, the EC value of the nutrient solution returning liquid at the outlet of the first proportional regulating valve 18 can be 0.3 times of the EC value of the nutrient solution of the water and fertilizer machine 19, namely, the opening degrees of the first inlet and the second inlet of the first proportional regulating valve 18 are regulated, so that the EC value detected by the EC sensor 16 is 0.3 times of the EC value of the nutrient solution of the water and fertilizer machine 19.
The EC value of the irrigation nutrient solution is set in the water-fertilizer machine 19, namely, the EC value of the nutrient solution in the water-fertilizer machine 19; the liquid fertilizer machine 19 automatically adjusts the liquid fertilizer mixture amount sucked into the liquid fertilizer preparing tank of the liquid fertilizer machine 19 through a fertilizer sucking pipeline according to the EC value of the nutrient solution of the liquid fertilizer machine 19, so that the liquid fertilizer mixture amount and the sterilized nutrient solution return liquid are mixed in proportion again, and the mixed nutrient solution is conveyed to the cultivation system 1 after reaching the irrigation EC value concentration of the cultivation system 1. The EC sensor 16 error is between-10% -10% of the desired EC value.
According to the relation between the first clean water intake pump 17 parameter and the first proportional regulating valve 18 corner combination concentration and conductivity, at the moment, the first proportional regulating valve 18 uses a PID algorithm to regulate, an EC control mathematical model is established, and a position type PID control model and a hysteresis compensation model are determined according to the mathematical model; the EC difference value is processed based on the position PID control model and the hysteresis compensation model to obtain an angular velocity change output value of the first proportional control valve 18, the change of the angular velocity of the motor of the first proportional control valve 18 is determined according to the angular velocity change output value, the change of the first proportional control valve 18 is obtained according to the change of the angular velocity, and then the EC value of the nutrient solution return is regulated to be about 0.3 times of the EC value of the nutrient solution of the water-fertilizer machine 19.
In an alternative embodiment, a liquid return pump is arranged between the first proportional regulating valve 18 and the standard-reaching liquid return tank 15, and the liquid return pump can convey the standard-reaching nutrient solution in the standard-reaching liquid return tank 15 to the first proportional regulating valve 18 so as to be input into the liquid fertilizer machine 19, and when the first liquid level sensor detects that the liquid level of the standard-reaching nutrient solution is equal to or less than a first preset liquid level, the liquid return pump is stopped, so that the nutrient solution cannot enter the liquid fertilizer machine 19.
In an alternative embodiment of the invention, the liquid return unit further comprises a liquid return device, a disinfection device and a filtration device.
The liquid return device is used for collecting nutrient liquid return liquid of the cultivation system 1, and an inlet of the filtering device is communicated with the liquid return device so that the filtering device can filter the nutrient liquid return liquid; the outlet of the filtering device is connected with the inlet of the sterilizing device 11, so that the sterilizing device 11 is used for sterilizing the filtered nutrient solution.
The nutrient solution of the cultivation system 1 is returned to the liquid return device, the nutrient solution in the liquid return device enters the filtering device for filtering, then enters the sterilizing device 11 for sterilization and disinfection, the standard nutrient solution output by the sterilizing device 11 enters the standard return tank 15, the standard nutrient solution in the standard return tank 15 and clear water conveyed by the first clear water inlet pump 17 (first water supply unit) are mixed through the first proportion regulating valve 18, and the mixed nutrient solution is returned to the water-fertilizer machine 19. Because the sterilized nutrient solution returns can not meet the irrigation requirement of the cultivation system 1, the water and fertilizer machine 19 performs fertilizer application and irrigation on the cultivation system 1 after fertilizer is prepared from the mixed nutrient solution returns.
By the arrangement, the nutrient solution circulation system is used in the closed mode production of the soilless culture system, the technical problem that nutrient solution in the facility vegetable soilless culture system cannot be reused is effectively solved, water and fertilizer of the soilless culture system are saved, and environmental pollution is reduced.
The controller may be a single-chip controller, a PLC controller, or other devices capable of implementing automatic control, and the controller is not specifically limited in the present invention.
In an alternative embodiment of the invention, the liquid return device comprises a liquid return tank 2 and a liquid return tank 3. A second level sensor and a return liquid output pump 4.
The liquid return tank 2 is used for collecting nutrient solution return liquid of the cultivation system 1, the liquid return tank 3 is used for storing the nutrient solution return liquid, an outlet of the liquid return tank 3 is communicated with an inlet of the filtering device, the second liquid level sensor is arranged in the liquid return tank 2, and the second liquid level sensor is used for monitoring the liquid level of the nutrient solution return liquid in the liquid return tank 2; the inlet of the liquid return output pump 4 is communicated with the outlet of the liquid return tank 2, and the outlet of the liquid return output pump 4 is communicated with the inlet of the liquid return tank 3 so as to convey the nutrient solution in the liquid return tank 2 back to the liquid return tank 3.
And the liquid return output pump 4 and the second liquid level sensor are both in communication connection with the controller.
Specifically, when the second liquid level sensor detects that the liquid level of the nutrient solution return liquid is greater than or equal to the first liquid level value, the return liquid output pump 4 is started to convey the nutrient solution return liquid in the return liquid tank 2 into the return liquid tank 3.
When the second liquid level sensor detects that the liquid level of the nutrient solution return liquid is smaller than the second liquid level value, the return liquid output pump 4 is stopped to stop conveying the nutrient solution return liquid to the return liquid pool 3.
By the arrangement, the nutrient solution in the liquid return tank 2 can be prevented from overflowing, and the liquid return output pump 4 can be prevented from idling.
In this embodiment, in order to prevent frequent start of the liquid return pump 4, the volume of the liquid return tank 3 needs to satisfy the volume of the liquid return pump 4 output at the rated flow rate for 5 minutes.
And, when the first liquid level sensor detects that the liquid level of the up-to-standard nutrient solution returns to be equal to or greater than the maximum liquid level value (namely the third preset liquid level), if the return liquid output pump 4 is still in the working state, in order to prevent the nutrient solution in the up-to-standard return liquid tank 15 from overflowing, the liquid manure machine 19 forcibly irrigates for a period so as to ensure that the nutrient solution in the up-to-standard return liquid tank 15 does not overflow.
In an alternative embodiment, the filtering means comprise a sand filter 6 and a laminated filter 7, wherein the inlet of the sand filter 6 is in communication with the outlet of the liquid return means, in particular the outlet of the liquid return reservoir 3 is in communication with the inlet of the sand filter 6 by means of the transfer pump 5; the inlet of the laminated filter 7 communicates with the outlet of the sand filter 6, and the outlet of the laminated filter 7 can communicate with the inlet of the disinfection device 11. Thus, through the filtration of the sand filter 6, the larger impurities in the nutrient solution return liquid can be filtered, and then the fine particles in the nutrient solution return liquid can be further filtered through the filtration of the laminated filter 7, so that the filtering effect of the filtering device is improved.
The sand filter 6 is also called a quartz sand filter and a sand filter, and is a filter which performs three-dimensional deep filtration by forming a sand bed by quartz sand with uniform particle size and the like as a filtering carrier. The sand filter 6 has small volume, is easy to install, saves space, can be installed outdoors, does not need to build houses, saves the price of soil buildings, can be installed in layers up and down, has compact structure and strong adaptability; has good corrosion resistance and long service life.
The laminated filter 7 can select filter discs with different precision according to water requirements, and particularly can select various specifications of 20 microns, 55 microns, 100 microns, 130 microns, 200 microns, 400 microns and the like, wherein the filter ratio is more than 85%. And, lamination filter 7 can thoroughly high-efficient backwash, because the filtration pore is opened completely during the backwash, in addition the centrifugal injection effect has reached other filters can't reach the cleaning performance. The backwashing process of each filter unit can be completed in 10 to 20 seconds. The laminated filter 7 can run fully automatically and continuously, the laminated filter 7 can adopt a modularized design, a user can choose and drop the parallel number of the filter units according to the needs, the flexibility is variable, and the interchangeability is strong. The field corner space can be flexibly utilized, and the installation occupation is small according to local conditions; and the laminated filter 7 is simple to maintain.
In an alternative embodiment of the invention, the present nutrient solution circulation system further comprises a second water supply unit and a turbidity sensor 8, where the turbidity sensor 8 may be arranged in the disinfection device 11 for detecting the turbidity of the filtered nutrient solution back. Here, the second water supply unit includes a second fresh water intake pump 10.
And, be provided with second proportional control valve 9 between filter equipment and degassing unit 11 to be used for adjusting the nutrient solution return after filtering and the inflow of clear water, thereby adjust the mixture ratio of nutrient solution return after filtering and clear water.
Specifically, the first inlet of the second proportional control valve 9 is communicated with the outlet of the filtering device (the laminated filter 7), the second inlet of the second proportional control valve 9 is communicated with the water outlet of the second clean water inlet pump 10, and the outlet of the second proportional control valve 9 is communicated with the inlet of the sterilizing device 11, so that filtered nutrient solution return liquid and clean water are mixed by the second proportional control valve 9 and then enter the sterilizing device 11, and thus, the turbidity of the nutrient solution return liquid reaches the required requirement through the opening degree adjustment of the first inlet and the second inlet of the second proportional control valve 9.
Here, the turbidity sensor 8 and the second proportional control valve 9 are both communicatively connected to the controller.
When the turbidity sensor 8 detects that the turbidity value of the nutrient solution return liquid is smaller than the lowest preset turbidity value, the controller regulates and controls the first inlet of the second proportional regulating valve 9 to be completely opened, and the second inlet of the second proportional regulating valve 9 to be closed, so that the filtered nutrient solution return liquid directly enters the disinfection device 11.
When the turbidity sensor 8 detects that the turbidity value of the nutrient solution return liquid is between the lowest preset turbidity value and the highest preset turbidity value, the controller adjusts the opening degrees of the first inlet and the second opening of the second proportional regulating valve 9, so that after clear water is mixed with the filtered nutrient solution return liquid, the turbidity value of the mixed nutrient solution return liquid is lower than the lowest preset turbidity value.
When the turbidity sensor 8 detects that the turbidity value of the nutrient solution return liquid is greater than or equal to the highest preset turbidity value, the controller controls the first inlet and the second inlet of the second proportional regulating valve 9 to be closed, so that the nutrient solution return liquid cannot enter the sterilizing device 11.
Here, a second liquid return circuit 20 is further arranged between the first inlet of the second proportional control valve 9 and the outlet of the filtering device, the outlet of the second liquid return circuit 20 is communicated with the liquid return tank 3, the inlet of the second liquid return circuit 20 is communicated with the outlet of the filtering device and the first inlet of the second proportional control valve 9 through a tee pipe, and a valve for controlling the second liquid return circuit 20 is further arranged at the inlet of the second liquid return circuit 20. Thus, the recycling treatment of the nutrient solution can be realized.
In an alternative embodiment of the invention, the present nutrient solution circulation system further comprises a first loop 12, a first valve 13, a second valve 14, and a detection sensor. Wherein, the export and the liquid return device intercommunication of first return circuit 12, the import of first return circuit 12 is through the export intercommunication of first valve 13 and degassing unit 11, and the first import of first proportional control valve 18 is through the export intercommunication of second valve 14 and degassing unit 11, and detection sensor is used for detecting whether nutrient solution return disinfection reaches standard to first valve 13 and second valve 14 and detection sensor communication connection.
Specifically, when the detection sensor detects that the nutrient solution return disinfection does not reach the standard, the second door valve is closed, the first valve 13 is opened, and the nutrient solution return which does not reach the standard flows back into the liquid return device (the liquid return tank 3) through the first liquid return loop 12 so as to be disinfected again.
When the detection sensor detects that the nutrient solution return disinfection reaches the standard, the second valve 14 is opened, the first valve 13 is closed, and the nutrient solution return reaching the standard enters the first proportional regulating valve 18 to be mixed with clear water and then enters the water and fertilizer machine 19.
The sterilizing device 11 may be an ultraviolet sterilizer, and the detection sensor may be an ultraviolet radiation sensor, and the ultraviolet intensity in the ultraviolet sterilizer is detected by the ultraviolet radiation sensor.
Here, the ultraviolet radiation sensor may be provided in the ultraviolet sterilizer, and the ultraviolet radiation sensor may be provided at an outlet of the ultraviolet sterilizer; or the ultraviolet radiation sensor is arranged at a preset distance from the ultraviolet sterilizer, so that the ultraviolet radiation intensity detected by the ultraviolet radiation sensor at a certain preset distance from the ultraviolet sterilizer meets a preset value, and the ultraviolet radiation sensor indicates that the nutrient solution liquid return sterilization meets the standard, namely that the ultraviolet radiation intensity of the ultraviolet sterilizer is large enough to sterilize the nutrient solution liquid return.
When the ultraviolet intensity detected by the ultraviolet radiation sensor is smaller than a preset value, the nutrient solution returns to the liquid for disinfection and does not reach the standard; when the ultraviolet intensity detected by ultraviolet rays is larger than or equal to a preset value, the nutrient solution returns to the liquid for sterilization, and the nutrient solution returns to the liquid for sterilization and reaches the standard.
In the above embodiment, the devices may be connected through a pipeline. And each electric equipment or electric device is in communication connection with the controller so as to realize automatic control.
When the nutrient solution circulating system provided by the invention works, a nutrient solution return liquid input pipeline conveys nutrient solution return liquid of a cultivation system 1 to a return liquid tank 2, non-disinfected nutrient solution return liquid enters a return liquid tank 3 through a return liquid output pump 4, enters a sand filter 6 through a conveying pump 5 and a sand filtering liquid inlet pipeline, is filtered by the sand filter 6, discharges larger impurities to a sewage tank through a sewage pipeline of the sand filter 6, and conveys the filtered nutrient solution return liquid into a laminated filter 7 through a laminated filter 7 input pipeline; after the nutrient solution returns to the liquid, the fine particles are discharged to a sewage pool through a sewage pipeline of the laminated filter 7 after being filtered by the laminated filter 7, and the filtered nutrient solution returns to the liquid to enter an ultraviolet sterilizer through an input pipeline of the sterilizer. The filtered nutrient solution returns to the ultraviolet sterilizer for automatic sterilization, and the unqualified nutrient solution returns to the liquid pool 3 through the first liquid return loop 12. The qualified nutrient solution return liquid (namely the standard reaching nutrient solution return liquid) enters the standard reaching return liquid tank 15 through a sterilized output pipeline of the sterilizer. The standard nutrient solution return in the standard return tank 15 is conveyed to the first inlet of the first proportional regulating valve 18 through a sterilized liquid storage tank output pipeline, and the first clear water inlet pump 17 conveys clear water to the second inlet of the first proportional regulating valve 18 through a clear water input pipeline. The opening degree of the first inlet and the second inlet of the first proportion adjusting valve 18 is adjusted so as to adjust the mixing proportion of the clear water and the return liquid of the up-to-standard nutrient solution, and then the mixed return liquid of the nutrient solution is conveyed to the water-fertilizer machine 19. The water and fertilizer machine 19 is used for preparing fertilizer for the mixed nutrient solution return liquid, the water and fertilizer machine 19 is used for automatically adjusting the fertilizer mixed liquid amount sucked into the fertilizer preparation tank of the water and fertilizer machine 19 through a fertilizer suction pipeline by setting the EC value of the irrigation nutrient solution, and the mixed nutrient solution return liquid is mixed with the mixed nutrient solution return liquid in proportion again, so that the mixed nutrient solution is conveyed to the cultivation system 1 after reaching the irrigation EC value concentration of the cultivation system 1.
The above-described embodiment of the apparatus is merely illustrative, and some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (8)
1. A nutrient solution return irrigation regulation method, characterized by comprising:
determining the liquid level of a standard-reaching liquid return tank, the liquid outlet flow of the standard-reaching liquid return tank and the liquid inlet flow of a liquid fertilizer machine, wherein the liquid inlet flow of the liquid fertilizer machine is the sum of the liquid outlet flow of the standard-reaching liquid return tank and the liquid inlet flow of clear water, the liquid fertilizer machine is used for preparing and supplying nutrient solution to a cultivation system, and the standard-reaching liquid return tank is used for storing the standard-reaching nutrient solution liquid returned by the cultivation system after being discharged and disinfected; a valve of the first proportional regulating valve is communicated with an outlet of the standard reaching liquid return tank, two valves of the first proportional regulating valve are communicated with a first water supply unit, and an outlet of the first proportional regulating valve is communicated with the water and fertilizer machine;
When the liquid level of the standard-reaching liquid returning tank is larger than a second preset liquid level and the ratio of the liquid outlet flow of the standard-reaching liquid returning tank to the liquid inlet flow of the liquid fertilizer machine is not in a first preset range, the controller adjusts the opening of the first valve and the opening of the second valve of the first ratio adjusting valve until the ratio of the liquid outlet flow of the standard-reaching liquid returning tank to the liquid inlet flow of the liquid fertilizer machine is in the first preset range, so that the stability of the nutrient solution components output by the liquid fertilizer machine is ensured;
when the liquid level of the standard-reaching liquid returning tank is larger than a first preset liquid level and smaller than or equal to a second preset liquid level, and the liquid outlet flow rate of the standard-reaching liquid returning tank is smaller than or larger than a second preset value, the controller adjusts the opening sizes of the first valve and the second valve of the first proportional regulating valve until the liquid outlet flow rate of the standard-reaching liquid returning tank is equal to the second preset value, so that the standard-reaching nutrient solution liquid returning in the standard-reaching liquid returning tank can meet the liquid returning rate required by normal irrigation of the liquid fertilizer machine;
the first proportional regulating valve comprises a first valve and a second valve which are in linkage, the outlet flow of the first proportional regulating valve is the sum of the flow of the first valve and the flow of the second valve, and the outlet flow of the first proportional regulating valve is constant no matter how the opening of the first valve and the opening of the second valve are changed, so that the flow of the mixed liquid flowing into the liquid fertilizer machine is constant;
The first preset liquid level is a liquid level stop position C of the standard-reaching liquid return tank, the second preset liquid level is a liquid level adjustment start position B of the standard-reaching liquid return tank, and the third preset liquid level is a liquid level overflow position A of the standard-reaching liquid return tank;
wherein, the nutrient solution liquid volume that reaches standard returns between B, C positions of the standard return tank is: v (V) BC ＝S×h BC S is the liquid surface area of the standard-reaching liquid return tank, h BC A pitch of B, C positions;
the outlet flow Q of the first proportional regulating valve is the flow Q of a valve connected with the standard-reaching liquid return tank 1 And a flow rate Q of two valves connected with the first water supply unit 2 Sum, q=q 1 +Q 2 ；
Setting the initial opening of the first valve to be theta, setting the initial opening of the second valve to be pi-theta, and acquiring the time t from the moment when the liquid level of the standard-reaching liquid return tank reaches the position B to the stop of the liquid fertilizer machine when the liquid level of the standard-reaching liquid return tank reaches the second preset liquid level in the process of irrigating the cultivation system by the liquid fertilizer machine, wherein the residual working time of the liquid fertilizer machine is the time when the liquid level of the standard-reaching liquid return tank reaches the second preset liquid level;
in order to ensure that the utilization rate of the nutrient solution returns to the maximum and ensure Q 1 X t is less than or equal to V BC The nutrient solution return can be ensured to be mixed in the whole irrigation process of the water and fertilizer machine;
Presetting the time for the standard nutrient solution return in the standard return tank to drop from the position B to the position C to be t 1 Wherein V is BC ＝Q 1 ×t 1 ，Q 1 ＝θ×Q/π，Q 2 ＝(π-θ)×Q/π；
When t 1 >At t, the controller can make the nutrient solution return utilization rate reach the maximum without adjusting the opening of the first proportional regulating valve;
when t 1 <At t, if the opening of the first proportional regulating valve is not regulated at this time, before the irrigation of the water and fertilizer machine is stopped, the standard nutrient solution in the standard return tank is completely utilized, that is, the liquid level of the standard nutrient solution reaches the C position or below the C position, and the standard nutrient solution is at t-t 1 In the time of (2), the valve does not have nutrient solution return liquid entering any more, and the outlet of the first proportional regulating valve can only convey clear water to the water and fertilizer machine, so that the water and fertilizer machine can carry out the process of t-t 1 Only clean water can be supplied to the cultivation system in the time, so that the utilization rate of nutrient solution return is reduced; in order to improve the utilization rate of the nutrient solution return, the controller controls the valve to be gradually closed at the angular speed of omega for t 1 Is just closed, ω=θ/t 1 ；
Wherein in the process that the opening of the valve gradually decreases at the angular speed of omega, the volume of the up-to-standard nutrient solution flowing through the valve is V 1 ＝Q 1 ×t 1 /2；
If V BC Greater than or equal to V 1 The liquid level in the standard-reaching liquid return tank can not be proved when the operation of the water and fertilizer machine is finished at the angular speedBelow the C-position of the metal plate, the controller controls the valve is omega=theta/t 1 Gradually closing the angular velocity of (a);
if V BC Less than V 1 The method includes the steps that when the operation of the water and fertilizer machine is finished, the liquid level in the standard-reaching liquid return tank is lower than the position C, and in order to ensure that the liquid level in the standard-reaching liquid return tank is higher than or at the position C when the operation of the water and fertilizer machine is finished, the controller controls a valve to be gradually closed at the angular speed of w';
the nutrient solution liquid-returning irrigation regulation method further comprises the following steps:
determining the liquid level of nutrient solution return in a return tank, wherein the return tank is used for collecting the nutrient solution return of the cultivation system;
when the liquid level of the nutrient solution return liquid in the return liquid tank is larger than a first liquid level value, controlling a return liquid output pump to start, and conveying the nutrient solution return liquid in the return liquid tank into a return liquid tank, wherein the return liquid tank is used for storing the nutrient solution return liquid; when the liquid level of the nutrient solution return in the return tank is smaller than a second liquid level value, controlling the return output pump to stop; wherein the first liquid level value is greater than the second liquid level value;
Determining the working state of the liquid return output pump;
when the liquid level of the standard-reaching liquid return tank is larger than a third preset liquid level and the liquid return output pump is in a working state, controlling the liquid fertilizer machine to start irrigation of the cultivation system so as to prevent the standard-reaching nutrient solution in the standard-reaching liquid return tank from overflowing; wherein the third preset liquid level is greater than the second preset liquid level.
2. The nutrient solution return irrigation regulation method of claim 1, wherein the first preset range is 0.25-0.3 and the second preset value is V BC /t。
3. A nutrient solution circulation system, characterized in that the nutrient solution return irrigation regulation method based on claim 1 or 2 comprises a return unit, an irrigation unit and a control unit;
the liquid return unit comprises a standard-reaching liquid return tank, and the standard-reaching liquid return tank is used for storing the sterilized standard-reaching nutrient liquid returned liquid discharged by the cultivation system;
the irrigation unit comprises a first water supply unit, a first proportional regulating valve and a water and fertilizer machine, wherein a valve of the first proportional regulating valve is communicated with an outlet of the standard-reaching liquid return tank, two valves of the first proportional regulating valve are communicated with the first water supply unit, and an outlet of the first proportional regulating valve is communicated with the water and fertilizer machine;
The control unit comprises a controller and a first liquid level sensor, the first liquid level sensor and the first proportional regulating valve are electrically connected with the controller, and the first liquid level sensor is used for detecting the liquid level of the up-to-standard nutrient solution return liquid in the up-to-standard return liquid tank;
the control unit further comprises a first flowmeter and a second flowmeter, and the first flowmeter and the second flowmeter are electrically connected with the controller; the first flowmeter is arranged between a valve of the first proportional regulating valve and the standard-reaching liquid return tank, and the second flowmeter is arranged between an outlet of the first proportional regulating valve and the liquid fertilizer machine.
4. A nutrient solution circulation system as claimed in claim 3, wherein the liquid return unit further comprises:
the liquid return device is used for collecting nutrient liquid return liquid of the cultivation system;
the filtering device is used for filtering the nutrient solution return liquid, and an inlet of the filtering device is communicated with the nutrient solution return device;
the sterilizing device is used for sterilizing and disinfecting the filtered nutrient solution, the inlet of the sterilizing device is communicated with the outlet of the filtering device, and the outlet of the sterilizing device is communicated with the standard-reaching liquid return tank.
5. The nutrient solution circulation system of claim 4, further comprising a second water supply unit and a turbidity sensor for detecting turbidity of the filtered nutrient solution back solution;
the device comprises a filter device, a disinfection device, a second proportional control valve, a turbidity sensor, a controller and a second proportional control valve, wherein the second proportional control valve is arranged between the filter device and the disinfection device, one valve of the second proportional control valve is communicated with an outlet of the filter device, two valves of the second proportional control valve are communicated with a water outlet of the second water supply unit, an outlet of the second proportional control valve is communicated with an inlet of the disinfection device, and the turbidity sensor is in communication connection with the second proportional control valve.
6. The nutrient solution circulation system of claim 4, further comprising:
the outlet of the first liquid return circuit is communicated with the liquid return device;
the inlet of the first liquid return circuit is communicated with the outlet of the disinfection device through the first valve;
a second valve through which a valve of the first proportional control valve can communicate with an outlet of the sterilizing device;
the detection sensor is used for detecting whether the nutrient solution returns to the liquid and disinfects to reach the standard, and the first valve, the second valve and the detection sensor are in communication connection with the controller.
7. The nutrient solution circulation system of claim 4, wherein the liquid return means comprises:
the liquid return tank is used for collecting nutrient solution return liquid of the cultivation system;
the liquid return tank is used for storing nutrient solution return liquid, and an outlet of the liquid return tank is communicated with an inlet of the filtering device;
the second liquid level sensor is used for monitoring the liquid level of the nutrient solution return liquid in the return liquid tank;
the liquid return output pump is characterized in that an inlet of the liquid return output pump is communicated with an outlet of the liquid return tank, an outlet of the liquid return output pump is communicated with an inlet of the liquid return tank, and the liquid return output pump, the second liquid level sensor and the controller are in communication connection.
8. The nutrient solution circulation system of claim 4, wherein the filtration device comprises:
the inlet of the sand filter is communicated with the outlet of the liquid return device;
and the inlet of the laminated filter is communicated with the outlet of the sand filter, and the outlet of the laminated filter can be communicated with the inlet of the disinfection device.
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| CN205030116U (en) * | 2015-09-29 | 2016-02-17 | 江苏农林职业技术学院 | Greenhouse water planting cyclic irrigation system |
| CN105557463A (en) * | 2015-12-16 | 2016-05-11 | 重庆市农业科学院 | Water and fertilizer integrated irrigation system and method for protected cultivation |
| CN205671182U (en) * | 2016-06-16 | 2016-11-09 | 上海孙桥现代农业联合发展有限公司 | A kind of residual nutrient solution recovery system |
| CN109258045B (en) * | 2018-08-30 | 2020-04-10 | 北京农业智能装备技术研究中心 | Tidal seedling water and fertilizer irrigation control system and method |
| CN209120892U (en) * | 2018-11-02 | 2019-07-19 | 福建省农业科学院科技干部培训中心 | A kind of batch production NFT cultivation system |
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