JPS6151843B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the concentration and
This device relates to a device that automatically adjusts the PH value, and instead of the conventional method of adjusting the culture solution concentration by replenishing concentrated stock solution by opening and closing a solenoid valve, and adjusting the culture solution PH value by adding acid or alkali.
By automatically adjusting the concentration and PH value of the culture solution through electrolysis through an ion exchange membrane, the concentration and PH value of the culture solution applied to the roots of growing crops can be ideally and gradually changed. The purpose is to provide a device for

Conventionally, the concentration and pH of the culture solution in hydroponic cultivation
As a means of automatically controlling the values, the concentration and PH values are measured using an electrical conductivity meter and a PH meter, and if these values deviate from the preset range values, they are automatically controlled by opening and closing a solenoid valve. A method is used in which a concentrated culture solution stock solution or an acid or alkali is added to return the value to a predetermined setting range. However, in this method, as mentioned above, concentrated stock solutions, acids, and alkalis are added to the culture medium for cultivation, which causes rapid changes in the concentration and PH value of the culture medium, causing damage to the plants being cultivated. Not only does this have an adverse effect, but the electromagnetic valve used also comes into direct contact with the undiluted solution, so materials that are highly chemically stable are required.

The present invention is a method and device that can completely solve the problems seen in the conventional methods described above, and includes two interfaces between the stock culture solution and the used culture solution, separated by a cation exchange membrane and an anion exchange membrane. The concentration of the culture solution can be adjusted by electrolyzing between two electrodes placed in the stock solution sandwiching the above two interfaces where the culture solution used is present, and the electrodes placed in the culture solution between the two interfaces. The PH value of the culture solution is automatically controlled by performing electrolysis with either one of the two electrodes.

The present invention will be explained below with reference to the drawings showing one embodiment thereof.

In the figure, reference numeral 1 denotes a culture solution tank, which contains a culture solution 2. A pump 3 supplies the culture solution 2 to a cultivation section 5 via a supply pipe 4, and from the cultivation section 5 via a drain pipe 6. The culture solution is configured to be returned to the culture solution tank 1. Furthermore, three stock solution tanks 19, 20, and 21 are associated with the culture solution tank 1. That is, the culture solution 2 in the culture solution tank 1 is transferred by the pump 16 through the circulation pipe 17 to the stock solution tanks 19, 20,
21 and returned to the culture solution tank 1 via the circulation pipe 18 from the stock solution tanks 19, 20, and 21. Each of the stock solution tanks 19, 20, 21
In this case, the introduction part of the culture solution 2 is separated from the culture solution stock solution by a cation exchange membrane and an anion exchange membrane. Therefore, each stock solution tank 19, 20, 21 constitutes three chambers by the cation exchange membrane and anion exchange membrane. In the figure, 30, 31, 32 indicate cation exchange membranes, 32, 34, 35 indicate anion exchange membranes, and 19', 19, 20', 20', 21', 21' indicate culture solution stock solution. . Each of the stock solution tanks 19, 20,
Each of the three chambers 21 is provided with an electrode plate for electrolysis. That is, the stock solution tank 19 is provided with electrode plates 23, 24, 42, the stock solution tank 20 is provided with electrode plates 25, 26, 41, and the stock solution tank 21 is provided with electrode plates 25, 26, 41.
are provided with electrode plates 27, 28, and 29.

In addition, the culture solution tank 1 and the stock solution tank 19, 20,
21 is associated with a concentration-PH regulator 9. That is, the concentration-PH regulator 9 is connected to the conductivity cell 7 placed in the culture solution tank 1 and the PH electrode 8, and each electrode of each stock solution tank 19, 20, 21 is connected to the concentration-PH regulator 9. It is connected to the DC power supply of the controller 9. Note that each electrode of this stock solution tank 19 is connected to a DC power source so that the two electrodes 23 and 24 inserted into the culture solution stock solution interact with each other, and the electrode 42 inserted into the culture solution is connected to the The two electrodes 23 and 24 are connected to a DC power source so as to selectively perform electrolysis with one of them. This relationship holds true for the other stock solution tanks 20 and 21 as well.

Note that 10, 12, 14, 11, 13, 1 in the figure
5 is a stock solution tank 19, 2 in the culture solution circulation path.
Solenoid valves 38, 3 inserted into the inflow and outflow sides of 0 and 21 and controlled to open and close by the concentration-PH regulator 9;
Reference numerals 9 and 40 indicate variable resistors for adjusting the current provided in the current conduction paths of the electrodes 23, 25, and 27 inserted into the culture source solution in the stock solution tanks 19, 20, and 21, and 22 indicates the concentration
37 is a water supply pipe connected to the culture solution tank 1, such as tap water, and 36 is the water supply pipe 37 of the PH regulator 9.
This is a solenoid valve attached to. Furthermore, the chain line in FIG. 1 indicates a control system.

In the above device, the culture solution 2 in the culture solution tank 1 is continuously or intermittently supplied to the cultivation section 5 through the supply pipe 4 by the pump 3, and the culture solution in the cultivation section 5 is again passed through the drain pipe 6. It returns to culture solution tank 1.
The concentration of the culture solution 2 in the culture solution tank 1 is determined by the conductivity cell 7.
Also, the PH value is measured by the PH electrode 8, and the results are given to the concentration-PH regulator 9.

Next, the concentration-PH regulator 9, which has been set to an arbitrary concentration range and PH range, checks the measured values of the concentration and PH of the culture solution 2 from the conductivity cell 7 and the PH electrode 8, and determines that the measured value is outside the set range. , the solenoid valves 10, 11, 1 are activated by the signal from the concentration-PH regulator 9.
2, 13, 14, and 15 and operate the pump 16 to circulate the culture solution 2 through the circulation pumps 17 and 18 into the stock solution tanks 19, 20, and 21. At the same time, the concentration-PH regulator 9 is connected to the DC power supply 22. provided in the stock solution tank 19, 20, 21 through the
Then, direct current is passed between the electrolytic electrodes 23, 24, 25, 26, and 27, 28 immersed in the culture solution stock solution 19', 20', 21' to perform electrolysis to further increase the concentration of the culture solution 2. Between the electrodes 27 and 29 provided in the stock solution tank 21 or between the electrodes 29 and 28
Electrolysis is performed by passing a direct current between the two to adjust the pH of the culture solution 2.
Keep the value within the set range. In addition, the stock solution tank 19, 2
Although the explanation of the electrodes 41 and 42 in 0 will be omitted, they function in the same way as the electrode 29. Stock solution tank 1
The culture solution 2 and the culture solution stock solution 19', 20', 21' passing through the cation exchange membranes 30, 3
1, 32 and anion exchange membranes 33, 34, 35
are in contact through In the illustrated apparatus, three types of stock solution tanks 19, 20, and 21 are used. The composition and concentration of the culture solution stored in these tanks is determined by fertilizers or combinations of fertilizers that do not cause precipitation or precipitation reactions even when concentrated, and cations that move at approximately the same speed through the ion exchange membrane due to electrophoresis under an electric field. Alternatively, since the combination of anions is a single cation or anion and the conductivity of the stock solution is almost the same in each tank, the following concentrations and compositions are used, for example.

Stock solution 19' in stock solution tank ₁₉ 256 g of Mg (NO ₃ ) 2.6H ₂ O in 600 ml of distilled water,
Ca (NO ₃ ) ₂・4H ₂ O472g, FeEDTA12g,
H ₃ BO ₃ 1.5g, MnCl ₂・4H ₂ O 1.0g, ZnCl ₂・
_7H2O0.2g , _CuSO4・_5H2O0.1g ,
(NH ₄ ) ₂ Dissolve 0.1g of MoO ₄ and add distilled water.
shall be.

Equivalence ratio of Ca; Mg:N 2:1:3 Stock solution 20' in stock solution tank 20 230 g of NH ₄ H ₂ PO ₄ and Ca in 700 ml of distilled water
(NO ₃ ) ₂ 4H ₂ Dissolve 236g of O and add distilled water to make 1
shall be. Equivalence ratio of Ca:N:P 1:2:3 Stock solution 21' in stock solution tank 21 Dissolve 202 g of KNO ₃ and 87 g of K ₂ SO ₄ in 700 ml of distilled water and add distilled water to make 1. K:N:S
Equivalent ratio of 3:2:1 Stock solutions 19', 2 with three compositions as above
Stock solution tank 19, 20, 2 with built-in 0', 21'
1, if the conductivity of the culture solution 2 is lower than the set value, the DC power supply 22 is activated by the signal from the concentration-PH regulator 9.
between electrodes 23 and 24, between electrodes 25 and 26, and between electrodes 2
A DC voltage is applied between electrodes 7 and 28 so that electrodes 23, 25 and 27 become anodes, and the stock solution tank 19
In the stock solution 19', cations such as Ca〓, Mg〓, Fe〓Mn〓 pass through the cation exchange membrane 30 into the culture solution, and anions such as NO ₃ ^- and Cl ^- pass through the anion exchange membrane 33. At the same time, the ions of the stock solutions 20' and 21' in the stock solution tanks 20 and 21 also migrate into the culture solution, and the conductivity of the culture solution 2 increases. The amount of each of the ions migrated into the culture solution is determined by the amount of electricity flowed and the composition of the stock solution in each stock solution tank. By adjusting the variable resistors 38, 39, and 40 attached to the lead ends of the anodes 23, 25, and 27, it is also possible to change the current ratio flowing into each stock solution tank, thereby allowing the culture to be removed from each stock solution tank. The amount of ions supplied into the liquid can be set.

On the other hand, if the concentration of the culture solution becomes higher than the set value, it is possible to reverse the above polarity and encourage the migration of ions from the culture solution to the stock solution, but there is a risk of the formation of insoluble salts in the stock solution. Therefore, by opening the solenoid valve 36, the water supply pipe 37 is opened.
A method was adopted in which tap water was supplied into the nutrient solution tank 1 through the circulation path 18 to lower the electrical conductivity of the culture solution 2.

Next, when the PH value of the culture solution 2 exceeds the set range value, a DC voltage is applied from the DC power supply 22 between the electrodes 29 and 28 so that the electrode 29 becomes the anode according to the signal from the concentration-PH regulator 9. The culture solution turns to the acidic side due to H ⁺ generated by the positive electrode reaction of water splitting and anions migrating from the stock solution 21' through the anion exchange membrane 35, and the PH value of the culture solution 2 returns to within the set range value. . In addition, when the pH value of the culture solution 2 becomes lower than the set range value, a DC voltage is applied from the DC power supply 22 between the electrodes 27 and 29 with the electrode 27 being the anode in response to a signal from the concentration-PH regulator 9. , OH ^- ions generated by the cathode reaction of water electrolysis pass through the cation exchange membrane 32 to the stock solution 21'.
The cations migrating from the culture medium move toward the alkaline side, and the pH value of the culture medium returns to within the set range.

In addition, FIG. 2 shows the electrical switch circuit of the concentration-PH regulator 9, SW ₁₁ , SW ₁₂ and SW ₁₃ are contacts that operate when the conductivity becomes lower than the set lower limit value, and SW ₂₁ is a contact that operates when the conductivity becomes lower than the set lower limit. The contacts SW ₃₁ , SW ₃₂ , and SW ₃₃ that operate when the temperature exceeds the set upper limit are
Contacts SW ₄₁ , SW ₄₂ and SW ₄₃ are contacts that operate when the PH value becomes lower than the set lower limit value, and are contacts that operate when the PH value becomes higher than the set upper limit value.

As can be seen from the above explanation, in the present invention, the electrolytic electrode for correcting the conductivity and the electrolytic electrode for correcting the PH value are jointly used, so that the electrolytic electrode for correcting the conductivity and the PH value are used together. Electrolysis for correction is not performed at the same time. According to experiments, the conductivity of the culture medium and
We discovered that when both PH values are outside the set range, performing electrolysis to correct conductivity and then electrolysis to correct PH requires less electricity and takes less time to correct. . For this reason, as shown in FIG. 2, it is preferable to configure the switch mechanism of the concentration-PH regulator to give priority to conductivity correction over PH correction.

As described above, the automatic culture solution composition adjustment device according to the present invention allows the same ions as plant nutrient ions in the culture solution to be added to the culture solution without directly adding concentrated stock solution, concentrated acid, or concentrated alkali to the culture solution. Since the composition of the culture solution can be automatically controlled by electrophoresis, there is no adverse effect on the plants due to sudden changes in the composition of the culture solution, so it has great industrial value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of hydroponic cultivation using the present invention, and FIG. 2 is an electrical switch circuit diagram of a concentration-PH regulator. 1... Culture solution tank, 2... Culture solution, 5... Cultivation section, 7... Conductivity cell, 8... PH electrode, 9... Concentration-PH regulator, 19, 20, 21... Stock solution tank , 19', 20', 21'...Culture solution stock solution, 22
...DC power supply, 23, 24, 25, 26, 27,
28, 29, 41, 42...Electrode for electrolysis, 3
0,31,32...Cation exchange membrane, 33,3
4, 35... Anion exchange membrane, 37... Water supply pipe,
38, 39, 40...variable resistor.

Claims (1)

[Scope of Claims] 1. A culture solution tank in which a PH detection means and a concentration detection means are arranged in the culture solution, and two opposed to each other with a cation exchange membrane and an anion exchange membrane interposed between the culture solution and the concentrated culture solution stock solution. at least one stock solution tank that forms an interface and in which the culture solution is in or can be in liquid contact with the culture solution in the culture solution tank; and a stock solution in the stock solution tank based on the pH measurement value. a PH regulator that performs electrolysis by applying a DC voltage between an electrode immersed in the culture solution and an electrode immersed in the culture solution in the stock solution tank, and automatically maintains the PH value of the culture solution within a set range; Based on the concentration measurement value, electrolysis is performed by applying a DC voltage between two electrodes immersed in the stock solution sandwiching two opposing interfaces in the stock solution tank, and the concentration of the culture solution is automatically kept within a set range. 1. An automatic culture solution composition adjustment device, characterized in that it is equipped with a concentration regulator that maintains the composition of the culture solution. 2. The automatic culture solution composition adjustment device according to claim 1, which uses a pump or a solenoid valve as a liquid connection means between the culture solution in the stock solution tank and the culture solution in the culture solution tank. 3 A plurality of stock solution tanks are provided, and in each tank, two interfaces are formed between the culture stock solution and the culture solution, which face each other via a cation exchange membrane and an anion exchange membrane, and the stock solution with the above two interfaces sandwiched therebetween. A culture solution composition automatic according to claim 1, characterized in that one pair of electrodes is disposed in the culture solution between the interfaces, and one electrode is disposed in one of the stock solution tanks in the culture solution between the interfaces. Regulator. 4. The culture according to claim 1, characterized by having a contact point configuration in which electrolysis for automatically adjusting the concentration is performed in advance when the PH value and concentration of the culture solution are outside the set range values. Liquid composition automatic adjustment device. 5. The automatic culture solution composition adjustment device according to claim 3, further comprising voltage variable means for the DC voltage applied between the pair of electrolytic electrodes provided in each stock solution tank.