JPH044848B2 - - 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.

Compared to soil cultivation, this type of culture medium cultivation has excellent characteristics, such as being more hygienic, allowing optimal growth conditions to be set for each cultivated plant, and easy cultivation management. It is extremely important to control the concentration of nutrient solution for 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) in which fertilizer etc. is dissolved is supplied from the undiluted solution tank 4 as the basis of Wm,
By mixing this stock solution M and dilution water Wr to dilute the stock solution M, a nutrient solution Wm having a fertilizer concentration suitable for cultivating 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 in the vicinity of the bed 16 in which the plants 14 are planted, and a drip nozzle 18 as a supply nozzle is connected to each branch pipe 12 for each plant. will be established. Therefore, the nutrient solution Wm pumped through the supply pipe 8 is
From the drip nozzle 18 to the plant 1 via the branch pipe 12
It is dripped and supplied in the vicinity of 4.

[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
The amount of raw solution depends on the flow rate wr to inhale and draw Wr.
With a diluter that obtains the nutrient solution Wm by setting mn, the dilution ratio of the stock solution M varies depending on the flow rate wr and pressure of the dilution water Wr, so it is not possible to obtain a constant concentration of the nutrient solution Wm, and it is not possible to obtain the nutrient solution Wm freely. It was not possible to change the concentration. Therefore, when the dilution ratio changes, it is necessary to change the fertilizer concentration of the stock solution M, which requires very troublesome 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 incorporating Wr, stock solution M with a specific concentration is added to it.
There is a method in which the necessary concentration is set by gradually adding Wm and monitoring the concentration of the nutrient solution Wm using a concentration sensor. 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. It was not possible to control the continuous supply of the nutrient solution Wm.

For this reason, the inventor decided to use dilution water for concentration setting.
We have proposed a plant cultivation nutrient solution mixing device that obtains nutrient solution Wm by continuously controlling the supply amount of stock solution M according to the flow rate wr of Wr.

Therefore, the present invention provides a plant cultivation nutrient solution mixing device that facilitates the management of the nutrient solution concentration to be supplied to the culture medium by taking into consideration the concentration data of the nutrient solution prepared according to the concentration setting and the flow rate of dilution water. For the purpose of providing.

[Means for solving problems]

The plant cultivation nutrient solution preparation device of this invention has a dilution water
Dilution water supply line where Wr is supplied (supply line 30)
and a nutrient solution supply path (supply path 34) for supplying the nutrient solution Wm to the culture medium (cultivation area 10), receives the dilution water from the dilution water supply path, and receives the dilution water from the dilution water supply path. or a nutrient solution mixing diluter 22 that dilutes the second stock solution Ma, Mb or both stock solutions to form the nutrient solution, and flows out the nutrient solution to the medium side according to the water pressure of the dilution water; A first stock solution tank 28A that stores the first stock solution, a second stock solution tank 28B that stores the second stock solution, and a stock solution supply path between the first stock solution tank and the nutrient solution mixing diluter. a first quantitative discharger 26A installed to supply the first stock solution to the nutrient solution mixing diluter;
a second quantitative discharger 26B installed in the stock solution supply path between the stock solution tank and the nutrient solution mixing diluter and supplying the second stock solution to the nutrient solution mixing diluter;
A driving means (a fixed-rate dispenser drive circuit 32) for driving the first or second fixed-rate dispenser, a flow rate sensor 20 installed in the dilution water supply path to detect the flow rate of the diluted water, and the nutrient solution. A concentration sensor 23 that is installed in a concentration detection unit 25 provided in the supply path and detects the concentration of the nutrient solution using electrical conductivity based on the amount of ions in the nutrient solution, and the flow rate data from the flow rate sensor, Together with the stock solution amount calculation section 241 that calculates the supply amount of the first or second stock solution to be supplied to the nutrient solution mixing diluter from the concentration data set according to the cultivation conditions, this stock solution amount calculation section calculates A stock solution amount correction section 242 is installed to correct the stock solution supply amount using the concentration data obtained by the concentration sensor, and generates a control output based on the corrected stock solution amount corrected by this stock solution amount correction section. A stock solution amount control device that operates the first or second metering dispenser through the drive means accordingly, and supplies the first stock solution, the second stock solution, or both stock solutions to the nutrient solution mixing diluter. 24.

[Effect]

In 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, but this stock solution amount mn is corrected by the concentration data of the nutrient solution Wm. , an appropriate stock solution volume mo is set, and the stock solution M set at this stock solution volume mo is mixed with the dilution water Wr, so the stock solution volume mo is supplied in immediate response to the flow rate fluctuation of the dilution water Wr, and the final output is While constantly monitoring the concentration of the nutrient solution Wm, the nutrient solution Wm having a set concentration is continuously prepared. Therefore, in this way, even if the accuracy of the stock solution supply means (quantitative dispensers 26A, 26B) is not high, the nutrient solution can be
It is possible to stabilize the concentration of Wm.

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 the plant cultivation nutrient solution mixing device of the present invention, control of the amount of stock solution mn is performed by adjusting the amount of stock solution according to the flow rate wr of the dilution water Wr with respect to the set concentration of the nutrient solution Wm.
If this is done using a stock solution amount calculation section 241 that calculates mn, and a stock solution amount correction section 242 that corrects the output stock solution amount of this stock solution amount calculation section 241 according to the output of the nutrient solution concentration detection means (concentration sensor 23), , set concentration Xn
Then, the stock solution volume mn calculated according to the flow rate wr of the dilution water Wr is corrected to an appropriate stock solution volume mo based on the nutrient solution concentration as the final output, and the nutrient solution Wm with a constantly stable concentration is continuously supplied. You can get it.

〔Example〕

FIG. 1 shows an embodiment of the plant cultivation nutrient 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 dilution water Wr.

The dilution water Wr is then supplied to a nutrient solution mixing diluter 22 installed as a nutrient solution mixing and diluting means for mixing with the stock solution M. The nutrient solution mixing diluter 22 is configured as a part of the supply pipe line 30,
The pipe constituting the supply pipe 30 may have a large cross-sectional area, or a nutrient solution mixing and diluting device for preparing and storing the nutrient solution Wm may be installed separately from the supply pipe 30. In this embodiment, an area with a large cross-sectional area is formed in the pipe constituting the supply pipe line 30.

First and second stock solution tanks 28A serve as stock solution storage means for storing first and second fertilizer stock solutions Ma and Mb to be supplied to this dilution water Wr,
28B is installed, and these stock solution tanks 28
The stock solutions Ma and Mb of A and 28B are supplied to the nutrient solution mixing diluter 2 through first and second quantitative dischargers 26A and 26B as electrically controlled stock solution supply means.
2. The stock solutions Ma and Mb are supplied to the nutrient solution mixing diluter 22, for example, by the metering dispenser 26.
It is press-fitted through A and 26B.

Further, in the supply pipe line 30 on the output side of the nutrient solution mixing diluter 22, a concentration detection unit 2 for detecting the concentration of the nutrient solution Wm prepared by the nutrient solution mixing diluter 22 is provided.
5 is provided, and this concentration detection section 25 is provided with a concentration sensor 23 that electrically detects the concentration of the nutrient solution Wm as a concentration detection means. As is well known,
Since the amount of ions in the nutrient solution Wm depends on the fertilizer concentration, which is proportional to the electrical conductivity, the ion content in the nutrient solution Wm
A concentration sensor 23 is used as a means for dipping an electrode into the liquid and measuring the value of the current flowing between the electrodes.
When fertilizers are dissolved in water, they become ionized and the electrical conductivity of the water changes. The fertilizer concentration can be measured based on this electrical conductivity, but since the electrical conductivity increases as the temperature rises, the concentration of the nutrient solution Wm is actually calculated by temperature correction.

Then, the flow rate signal obtained by the flow rate sensor 20
Vwr is applied to the stock solution amount calculation unit 241 of the stock solution amount control device 24 installed as a stock solution amount control means. The raw liquid amount calculation unit 241 calculates the concentration Xn from the flow rate data obtained from the flow rate signal Vwr that changes every moment and the concentration
Calculate the amount of stock solution mn required to obtain . For example, this stock solution amount calculation unit 241 is equipped with a storage means that stores stock solution amount data corresponding to the flow rate data and concentration data, and by inputting the flow rate data and concentration data, It may be possible to read out the stock solution amount data, or it may be carried out using an arithmetic expression.

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 concentration setting 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 at the same time based on the stock solution amount signal Vmo,
For example, each stock solution is automatically
By setting the blending ratio of Ma and Mb, the blending ratio can be obtained for determining the concentration. Therefore, the stock solution control signal Vcm is a data signal representing the amounts of stock solutions Ma and Mb and their blending ratio for setting the required concentration.

The stock solution control signal Vcm is applied to a metering dispenser drive circuit 32 installed as a driving means for the stock solution supply 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 and 26B have opening/closing times controlled according to the supply ratio of the stock solutions Ma and Mb set in the stock solution control signal Vcm, and the set concentration is determined based on the flow rate wr of the dilution water Wr.
Necessary amount of stock Ma or stock Mb to obtain Xn
Alternatively, both are supplied to the nutrient solution mixing diluter 22.

The supplied stock solutions Ma and Mb are stirred in accordance with the flow of dilution water Wr inside the nutrient solution mixing diluter 22 to obtain a nutrient solution Wm of the required concentration, which is then supplied to the cultivation area through the supply pipe 34. be done. In that case, the nutrient solution
Wm is the nutrient solution supply device 6 as shown in FIG.
is sent to the cultivation area 10 with the necessary pressure.

Therefore, according to such a cultivation nutrient solution mixing device, when the concentration of the nutrient solution Wm is set, the required amount of the nutrient solution Ma, Mb is prepared according to the flow rate wr of the dilution water Wr.
The supply amount of the necessary stock solutions Ma and Mb is controlled immediately in response to the flow rate fluctuations of the dilution water Wr, and the deviation is calculated by comparing the set concentration and the concentration of the nutrient solution Wm. Since the stock solution amount mn is corrected to the appropriate stock solution amount mo according to the deviation, a nutrient solution Wm with a stable concentration can always be obtained. Further, the stock solution amount control device 24 of the embodiment can be configured by an arithmetic processing device such as a microcomputer to realize stock solution amount control.

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 is basically performed using feed-forward control, but it is also a type 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 set concentration.

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 is controlled based on the calculation result. The amount of stock solution can be controlled immediately in response to fluctuations in the flow rate of the nutrient solution, and the set concentration and the concentration of the nutrient solution are compared and the amount of stock solution is corrected based on the error, so the nutrient solution at the set concentration of stock solution is always mixed. Since the nutrient solution can be diluted and continuously prepared and supplied to the culture medium, and the supplied nutrient solution is always set at an appropriate concentration, it is possible to promote 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... Nutrient solution mixing diluter, 23... Concentration sensor, 24 ...Standard solution amount control device, 25...Concentration detection unit, 26A...First fixed quantity dispenser, 26B...Second fixed quantity dispenser, 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)

[Scope of Claims] 1. A dilution water supply channel that is inserted between a dilution water supply channel to which dilution water is supplied and a nutrient solution supply channel that is to supply nutrient solution to the culture medium to receive the dilution water from the dilution water supply channel; A nutrient solution mixing diluter that dilutes the first or second stock solution or both stock solutions with the dilution water to form the nutrient solution, and flows out the nutrient solution to the medium side according to the water pressure of the dilution water. , a first stock solution tank for storing the first stock solution, a second stock solution tank for storing the second stock solution, and a stock solution supply path between the first stock solution tank and the nutrient solution mixing diluter. a first quantitative discharge device installed to supply the first stock solution to the nutrient solution mixing diluter; and a first fixed amount dispensing device installed in the stock solution supply path between the second stock solution tank and the nutrient solution mixing diluter. a second fixed-rate dispenser for supplying the second stock solution to the nutrient solution mixing diluter; a driving means for driving the first or second fixed-rate dispenser; a flow rate sensor that detects the flow rate of dilution water; and a concentration sensor that is installed in a concentration detection section provided in the nutrient solution supply path and that detects the concentration of the nutrient solution based on electrical conductivity based on the amount of ions in the nutrient solution. and a stock solution amount for calculating the supply amount of the first or second stock solution to be supplied to the nutrient solution mixing diluter from the flow rate data from the flow rate sensor and concentration data set in advance according to cultivation conditions. Along with the calculation section,
A stock solution amount correction section is installed to correct the stock solution supply amount calculated by the stock solution amount calculation section using the concentration data obtained by the concentration sensor, and a control output based on the corrected stock solution amount corrected by the stock solution amount correction section is installed. generated, and in response to this control output, 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 nutrient solution mixing diluter. Plant cultivation 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 mixing device according to claim 1, characterized in that: