JPH044849B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plant cultivation nutrient solution preparation device used for hydroponic cultivation, etc., and in particular, it relates to a plant cultivation nutrient solution preparation device for use in hydroponic cultivation, etc., and in particular, a highly concentrated undiluted solution of a nutrient solution necessary for cultivation such as fertilizer. and the dilution of highly concentrated nutrient solutions with agricultural water, etc.

[Conventional technology]

In contrast to conventional soil cultivation, which uses soil to cultivate plants, plants are planted in an artificial culture medium such as fibrous materials, and nutrients such as fertilizers necessary for growth are dissolved in water. There is culture cultivation in which cultivation is performed by supplying a nutrient solution.

Medium cultivation is more hygienic than soil cultivation, allows you to set optimal growth conditions for each cultivated plant, and
Although it has excellent characteristics such as easy cultivation management, it is extremely important to manage the concentration of the nutrient solution for the plants.

FIG. 2 shows an outline of a general hydroponic apparatus for growing plants. This hydroponic cultivation device uses a nutrient solution mixing and diluting device 2 along with dilution water Wr such as agricultural water.
A highly concentrated nutrient solution (hereinafter referred to as undiluted solution M) containing dissolved fertilizer, etc. as the basis of Wm is supplied from the undiluted solution tank 4, and this undiluted solution M is mixed with dilution water Wr.
By diluting the nutrient solution Wm, a nutrient solution Wm with a fertilizer concentration suitable for growing plants is obtained.

Then, this nutrient solution Wm is sent to the cultivation area 10 via a nutrient solution supply device 6 consisting of a pressure pump, a filter, etc., and a supply pipe line 8. In the cultivation area 10, a plurality of branch pipes 12 attached to the supply pipe line 8 are arranged near the bed 16 in which the plants 14 are planted, and a drip nozzle 18 as a supply nozzle is installed for each branch pipe 12 for each plant. will be established. Therefore,
The nutrient solution Wm pressure-fed through the supply pipe line 8 is dripped and supplied to the vicinity of the plants 14 from the drip nozzle 18 via the branch pipe 12.

[Problem that the invention seeks to solve]

In such a hydroponic cultivation device, it is necessary to set the formulation of the nutrient solution Wm to the optimal fertilizer distribution and concentration for the plants 14, and the fertilizer distribution and concentration differ depending on the plant. Since it varies greatly depending on the growth state and weather conditions, it is necessary to set the fertilizer distribution and concentration of the nutrient solution Wm while referring to growth data and weather data each time.

Conventionally, in mixing and diluting the nutrient solution Wm for diluting the stock solution M by mixing it with the dilution water Wr, the dilution water
In a diluter that sucks in Wr, the dilution ratio of the stock solution M fluctuates depending on the flow rate wr of the dilution water Wr and pressure fluctuations, making it impossible to obtain a constant concentration of the nutrient solution Wm, and the concentration can be changed freely. It was something that could not be done. Therefore, if the dilution ratio changes, it is necessary to respond by changing the fertilizer concentration of the stock solution M.
It required extremely tedious work.

In addition, as a way to automate the conventional preparation of nutrient solution Wm, a certain amount of dilution water is added to the nutrient solution mixing and diluting device 2.
After adding Wr, a stock solution M of a specific concentration is gradually added therein, and the concentration of the nutrient solution Wm is monitored using a concentration sensor to set the required concentration. This is because the nutrient solution Wm is prepared by taking in the dilution water Wr in fixed amounts, so there is no need to continuously correct the concentration. Continuous supply control of the nutrient solution Wm cannot be performed, and the nutrient solution
In order to set a constant concentration for Wm, an expensive concentration sensor was required.

For this reason, the flow rate of dilution water Wr for the concentration setting is
A method of preparing a nutrient solution for cultivating plants has been proposed in which a nutrient solution Wm is obtained by continuously controlling the supply amount of the stock solution M according to wr.

SUMMARY OF THE INVENTION An object of the present invention is to provide a plant cultivation nutrient solution mixing device that enables appropriate concentration management by taking into account the concentration data of the nutrient solution prepared according to the concentration setting and the flow rate of dilution water.

[Means for solving problems]

The plant cultivation nutrient solution mixing device of the present invention receives dilution water Wr from a dilution water supply line (supply pipe line 30), and obtains a nutrient solution Wm by diluting the first and second stock solutions Ma and Mb. Mixing dilution tank 2 that stores
2, a first stock solution tank 28A that stores the first stock solution to be supplied to the mixed dilution tank, and a second stock solution tank 28B that stores the second stock solution that should be supplied to the mixing dilution tank. , a first quantitative discharger 26A installed in the stock solution supply path between the first stock solution tank and the mixing and diluting tank to supply the first stock solution to the mixing and diluting tank;
and a second quantitative discharger 26B installed in the stock solution supply path between the second stock solution tank and the mixing dilution tank and supplying the second stock solution to the mixing and dilution tank; Driving means for driving the first or second metering dispenser (metering dispenser drive circuit 3
2), a flow rate sensor 20 installed in the dilution water supply path to detect the flow rate of the dilution water, and a flow rate sensor 20 that is installed in the dilution water supply path to detect the flow rate of the dilution water; a stirring means (stirring pipe line 25) for returning the nutrient solution in the mixing and diluting tank to the tank; The concentration sensor 23 detects the concentration of the nutrient solution, the flow rate data from the flow rate sensor, and the concentration data set in advance according to the cultivation conditions are used to determine whether the first or second amount to be supplied to the mixing dilution tank is determined. A stock solution amount calculation unit 241 is installed to calculate the supply amount of the stock solution, and a stock solution amount correction unit 242 is installed to correct the stock solution amount calculated by the stock solution amount calculation unit using the concentration data obtained by the concentration sensor.
The stock solution amount correction unit generates a control output based on the corrected stock solution amount, and operates the first or second metering dispenser through the drive means in accordance with the control output, and The present invention is characterized by comprising a stock solution amount control device 24 for supplying the stock solution or both stock solutions to the mixing and dilution tank.

[Effect]

According to this cultivation nutrient solution mixing device, the necessary stock solution amount mn can be obtained for the concentration setting of the nutrient solution Wm and the flow rate wr of the dilution water Wr.
The concentration data of Wm is taken into account and corrected, an appropriate stock solution volume mo is set, and the stock solution M set to this stock solution volume mo is mixed with the dilution water Wr, so it can immediately respond to fluctuations in the flow rate of the dilution water Wr. While the raw solution amount mo is controlled, the concentration of the final output nutrient solution Wm is constantly monitored, and the nutrient solution Wm having a set concentration is continuously prepared. Therefore, if you do this, the nutrient solution
It is possible to precisely control the concentration of Wm and maintain a stable concentration.

In this case, the preparation of the nutrient solution Wm consists of multiple stock solutions Ma,
When using Mb, this refers to mixing and diluting each of the stock solutions Ma, Mb and dilution water Wr, and when using a single stock solution M, mixing and diluting the stock solution M and dilution water Wr.

In this cultivation nutrient solution mixing device, a mixing and diluting tank 22 for diluting the stock solution M by mixing the stock solution M and dilution water Wr is installed, and the nutrient solution Wm in this mixing and dilution tank 22 is stirred. If a stirring means (stirring pipe 25) is installed, the concentration can be detected while stirring the nutrient solution Wm, so that the concentration can be precisely controlled.

〔Example〕

FIG. 1 shows an embodiment of the plant cultivation solution preparation device of the present invention.

For example, agricultural water such as groundwater or rainwater is used as the dilution water Wr for obtaining the nutrient solution Wm of a specific concentration. This dilution water Wr is continuously supplied from a tank or the like (not shown) through a supply pipe line 30 serving as a dilution water supply line. A flow rate sensor 20 is installed as a detection means, and the flow rate wr of the dilution water Wr is electrically detected by this flow rate sensor 20.

Vwr indicates a flow rate signal representing the flow rate wr of the dilution water Wr.

This dilution water Wr contains the first and second stock solutions Ma,
It is supplied to a mixing dilution tank 22 installed as a mixing diluter for mixing with Mb. and,
This mixed dilution tank 22 has a nutrient solution inside it.
A stirring pipe line 25 is provided as a stirring means for stirring the nutrient solution Wm by taking out Wm from the bottom side and returning it to the mixing dilution tank 22 again. A stirring pump 27 for circulating the nutrient solution Wm is installed in the stirring pipe 25, and the nutrient solution Wm is taken out from the mixing and dilution tank 22, falls from above, and is stirred. As a result, the stock solutions Ma, Mb and dilution water Wr
are mixed, and the stock solution Ma, Mb with dilution water Wr
dilution takes place quickly.

First and second stock solution tanks 28A, 28B are installed as stock solution storage means for storing first and second fertilizer stock solutions to be supplied to the mixing dilution tank 22, and these stock solution tanks 28A, 28
The stock solutions Ma and Mb of B are supplied to first and second metering dispensers 2 as electrically controlled stock solution supply means.
It is supplied to the mixing dilution tank 22 via 6A and 26B. Mixing dilution tank 2 for stock solutions Ma and Mb
The supply to 2 is, for example, by metering dispenser 26A, 2
Set the required amount of stock solution Ma or Mb to drip through 6B by gravity or a specific pressure.

The mixing dilution tank 22 also includes a nutrient solution as a concentration detection means for detecting the concentration of the nutrient solution Wm.
A concentration sensor 23 is installed to electrically detect the concentration of Wm. As is well known, the amount of ions in the nutrient solution Wm depends on the fertilizer concentration, which is proportional to the electrical conductivity. Therefore, an electrode is immersed in the nutrient solution Wm and the value of the current flowing between the electrodes is measured. A concentration sensor 23 is used as a means to do this. When fertilizers are dissolved in water, they become ionized and the electrical conductivity of the water changes. Fertilizer concentration can be measured by this electrical conductivity, but since electrical conductivity increases as the temperature rises, it is actually possible to measure the fertilizer concentration by temperature correction.
Calculate the concentration of Wm.

Then, the flow rate signal obtained by the flow rate sensor 20
Vwr is applied to the stock solution amount calculation section 241 of the stock solution amount control device 24 installed as a stock solution amount control means. The stock solution amount calculation unit 241 calculates the stock solution amount necessary to obtain the concentration Xn from the flow rate data obtained by the constantly changing flow rate signal Vwr and the concentration data representing the concentration Xn set as necessary. mn
Calculate. For example, this stock solution amount calculation section 241
For the flow rate data and concentration data, a storage means is installed that stores the raw solution volume data according to the flow rate data, and the necessary raw solution volume data is read out by inputting the flow rate data and concentration data. do.

The stock solution amount signal Vmn representing the stock solution amount mn calculated by the stock solution amount calculation unit 241 is applied to the stock solution amount correction unit 242 which corrects the stock solution amount mo to an appropriate stock solution amount according to the concentration of the nutrient solution Wm. Stock solution amount correction section 242
compares the concentration signal Vn from the concentration sensor 23 and the set concentration signal
The stock solution amount signal Vmn representing the stock solution amount is corrected to output the stock solution amount signal Vmo representing the appropriate stock solution amount mo.

In addition, even if the stock solution amount correction unit 242 corrects the stock solution amount for a specific period of time, the error between the set concentration and the actual concentration of the nutrient solution Wm becomes large, and if the correction is not performed, the error When the concentration exceeds a certain value, a concentration abnormality signal Vx is generated. Such a concentration abnormality occurs, for example, due to a shortage of the stock solutions Ma and Mb, a failure of the metering dispensers 26A and 26B, and the like. This concentration abnormality signal Vx can be extracted to drive the concentration abnormality alarm 31 to notify the concentration abnormality. The concentration abnormality alarm 31 can be configured with optical means such as a lamp, sound generating means such as a buzzer, and the like.

Then, the amount of stock solution obtained by the stock solution amount correction unit 242
The stock solution amount signal Vmo representing mo is applied to the stock solution amount supply control section 243 to generate the stock solution control signal Vcm for supplying the necessary stock solution amount mo. In this case, for example, the blending ratio of the stock solutions Ma and Mb is calculated simultaneously based on the stock solution volume signal Vmo, and for example, each stock solution Ma, Mb is automatically calculated according to the concentration data.
By setting the blending ratio of Mb, the blending ratio can be obtained for determining the concentration. Therefore, the stock control signal
Vcm is the stock solution Ma for setting the required concentration,
This is a data signal representing the amount of Mb and its blending ratio.

The stock solution control signal Vcm is applied to a metering dispenser drive circuit 32 installed as a stock solution supply drive means, and the metering dispenser drive circuit 32 receives the stock solution control signal.
Drive signals Va and Vb corresponding to Vcm are output and applied to each metering dispenser 26A and 26B. Fixed amount dispenser 26
A, 26B indicate the fixed quantity dispenser 2 for the supply ratio of the stock solutions Ma, Mb set in the stock solution control signal Vcm.
The operation time of 6A and 26B is controlled, and the dilution water
An amount of stock solution Ma or stock solution Mb, or both, necessary to obtain the set concentration Xn with respect to the flow rate wr of Wr is supplied to the mixing dilution tank 22.

The supplied stock solutions Ma and Mb are stirred with the dilution water Wr inside the mixing and dilution tank 22 to obtain the nutrient solution Wm of the required concentration, and the supply channel 3 is passed to the cultivation area 10 side.
Supplied through 4. In that case, the nutrient solution Wm is
As shown in FIG. 2, the nutrient solution is sent to the cultivation area with the necessary pressure by the nutrient solution supply device 6.

Therefore, according to such a nutrient solution mixing device, once the concentration of the nutrient solution Wm is set, the dilution water is
The required amount of stock solutions Ma and Mb is supplied and mixed according to the flow rate wr of Wr, and the supply amount of the necessary stock solutions Ma and Mb is controlled immediately in response to fluctuations in the flow rate of dilution water Wr. Since the concentration of the solution Wm is compared with the concentration of the solution Wm to find the deviation, and the stock solution amount mn is corrected to the appropriate stock solution amount mo according to the deviation, the nutrient solution Wm with a stable concentration can always be obtained. The stock solution amount control device 24 is constituted by an arithmetic processing device such as a microcomputer, and can control the stock solution amount.

By the way, in preparing this plant cultivation nutrient solution, the method of diluting the stock solution is to first detect the flow rate of the dilution water, calculate the theoretical value so that the set concentration is achieved, and then control the metering discharge device using feed forward control. I'm going. This relationship is clear from the fact that drive signals Va and Vb are obtained according to the density data.
That is, when performing this control, it is not always possible to dilute to the set concentration because there is an error in the flow meter, metering ejector, and concentration of the undiluted fertilizer solution. Therefore, it is necessary to measure the concentration of the diluted nutrient solution with a concentration sensor, compare the measured value with a set concentration, and calculate the difference. Calculation of such a difference is taken into account in the next dilution operation, and the theoretical value is corrected to correct the previous error to perform feed forward control. In the cultivation of plants, rapid control is not necessary, and even if there is some error, it will not lead to withering or death, and such gentle control is possible. By repeating such correction of the theoretical value, ideal dilution without error becomes possible. The preparation of this cultivation nutrient solution basically uses feed-forward control, but it is also a kind of learning control in that the theoretical value, that is, the target value, is corrected by feeding back the errors of the equipment used. This is what we are doing.

In the embodiment, the first and second stock solution tanks 28A and 28B are installed to store two types of stock solutions Ma,
We have explained the case of using Mb, but it is possible to mix fertilizers with the necessary ingredients in advance and set up the necessary stock solution tank, or to install a stock solution tank for each fertilizer to avoid inconveniences caused by combinations of fertilizers. , fertilizer may be mixed according to the concentration setting.

Further, in this invention, the fertilizer stock solution is stored in the first stock solution tank 28A, and the PH is stored in the second stock solution tank 28B.
If the concentration correction stock solution is stored, it can be used to correct the PH concentration.

〔Effect of the invention〕

As explained above, according to the present invention, the amount of stock solution required for the flow rate of dilution water is calculated according to the concentration setting of the nutrient solution, and the amount of stock solution to be supplied to the mixing and dilution tank based on the calculation result. Since we control
The amount of stock solution can be controlled immediately in response to fluctuations in the flow rate of dilution water, and the amount of stock solution is compared with the set concentration of nutrient solution and corrected according to the error, so it is possible to mix nutrient solution with the set concentration of stock solution. The nutrient solution can be diluted and continuously prepared and supplied to the culture medium, and the concentration of the nutrient solution can be optimized, thereby facilitating the growth of plants.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the plant cultivation nutrient solution mixing device of the present invention, and FIG. 2 is a block diagram showing an outline of a general plant nutrient solution mixing device. Wm... Nutrient solution, Wr... Dilution water, Ma... First stock solution, Mb... Second stock solution, 20... Flow rate sensor, 22... Mixing dilution tank, 23... Concentration sensor, 24... ...Natural liquid amount control device, 25...Stirring pipe line (stirring means), 26A...First metering dispenser,
26B...Second quantitative discharge device, 27...Stirring pump (stirring means), 28A...First stock solution tank,
28B... Second stock solution tank, 30... Supply pipe line (dilution water supply line), 31... Concentration abnormality alarm, 32
...Quantitative dispenser drive circuit (drive means), 34...
Supply path (nutrient solution supply path), 241... Raw solution amount calculation section,
242...Standard solution amount correction section.

Claims (1)

[Claims] 1. Receiving dilution water from the dilution water supply path,
and a mixing dilution tank that stores a nutrient solution obtained by diluting a second stock solution; a first stock solution tank that stores the first stock solution to be supplied to the mixing and dilution tank; a second stock solution tank for storing the second stock solution to be supplied; and a stock solution supply path between the first stock solution tank and the mixing and dilution tank for mixing and diluting the first stock solution. a first fixed-rate dispenser for supplying the liquid to the tank; and a second liquid dispensing device installed in the liquid supply path between the second liquid liquid tank and the mixing and diluting tank to supply the second liquid liquid to the mixing and diluting tank. 2, a driving means for driving the first or second fixed quantity dispenser, a flow rate sensor installed in the dilution water supply path to detect the flow rate of the dilution water, and the mixing dilution tank. stirring means for stirring the nutrient solution in the mixing and diluting tank by pulling the nutrient solution from the bottom of the mixing and diluting tank with a pump, and stirring the nutrient solution in the mixing and diluting tank; a concentration sensor that detects the concentration of the nutrient solution using electrical conductivity based on the amount of ions; and a concentration sensor that supplies the nutrient solution to the mixed dilution tank from the flow rate data from the flow rate sensor and the concentration data set in advance according to the cultivation conditions. Should the first or second
A stock solution amount calculation section is installed to calculate the supply amount of the stock solution, and a stock solution amount correction section is installed to correct the stock solution amount calculated by the stock solution amount calculation section using the concentration data obtained by the concentration sensor. A control output is generated based on the corrected stock solution amount corrected by the amount correction section, and the first
or a stock solution amount control device that operates a second quantitative discharger to supply the first stock solution, the second stock solution, or both stock solutions to the mixing dilution tank. Nutrient solution mixing device. 2. The stock solution amount control device is configured to generate an abnormal concentration signal when the error in the concentration of the nutrient solution becomes large with respect to the set concentration, and the alarm is activated by the abnormal concentration signal. A plant cultivation nutrient solution preparation device according to claim 1, characterized in that: