JP2770884B2 - Irrigation unevenness leveling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a device for leveling unevenness in irrigation for making the water content in a culture medium substantially uniform in nutrient solution cultivation using rock wool as an artificial culture medium.

[Prior art]

In general, an artificial medium, particularly a medium using a rock wool mat, has one feature that a large amount of water is retained by an excellent water retaining function by a capillary action. But,
A good water retention function is, in other words, a poor drainage property, which also makes crop cultivation difficult. For this reason, some proposals and attempts have been made to solve the above-mentioned inconvenience by providing a means for adjusting the water content in the culture medium. For example, laying a hydrophilic non-woven fabric under a rock wool bed and dropping it to one side to discharge excess water in the bed by the suction force of capillary action of the hydrophilic non-woven fabric (see Japanese Utility Model Laid-Open No. 63-4670) ).

[Problems to be solved by the invention]

In the above-described method that depends on the suction force due to the capillary action of the nonwoven fabric, not only does it take a certain amount of time to drain, but also the water content in the medium is uniquely determined by the length of the drip of the hydrophilic nonwoven fabric. In practice it was very difficult. SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for leveling unevenness in irrigation that makes the water content in a culture medium almost uniform as quickly as possible in view of the actual situation such as lyrics.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides a method in which a plurality of artificial media are continuously laid in a receiving member, and a water collecting device is disposed between the contact surfaces of the respective artificial media and the receiving member. Each of the conduits of the water collecting tool is connected to one communication pipe, and at the end of the communication pipe, a head difference adjusting means capable of providing an appropriate head difference lower than that of the water collecting tool is connected. It was done. The above-mentioned head difference adjusting means can be composed of a tubular body to which the end of the communicating pipe is connected, and an overflow pipe which is inserted into the bottom of the tubular body so as to be able to move up and down. The head difference adjusting means also includes a cylinder and an electromagnetic valve connected to both ends of the communication pipe, and an E1 electrode that issues a valve closing signal for the electromagnetic valve when the water level in the cylinder falls below the lower limit level, and An E2 electrode that issues a valve opening signal for the solenoid valve when the water level in the cylinder is equal to or higher than the upper limit level.The difference in height between the lower end of the E1 electrode and the lower end of the E2 electrode is reduced, and the lower end of the E2 electrode. It is also possible to adopt a configuration in which the above-mentioned solenoid valve is disposed further below.

[Action]

The pF value of the rock wool medium by the “sand column method” changes depending on the properties of the rock wool mat that constitutes the water collecting device and the artificial medium, and the pF value and the head difference adjusting means described above are used. It has been confirmed that a correlation is established between the head differences h to be formed. Therefore, when h is set from a desired pF value and a negative pressure suction force corresponding to h is applied to each water collecting tool, an extra amount is obtained. The water contained in the culture medium is sucked and discharged to have a desired pF value. In addition, the liquid is transferred from the bed having a high moisture content to the bed having a low moisture content through the communication pipe, so that unevenness of irrigation is leveled.

【Example】

In the first embodiment shown in FIG. 1 and FIG.
A cultivation bed is formed by continuously laying a plurality of rock wool artificial culture media 3 in a dish-shaped receiving member 2 placed thereon, and a supply pipe 4 attached to the bed.
A liquid is supplied to each artificial culture medium 3 by a thin tube 5. As shown in FIG. 2, a conduit 7 having an open end covered with a water collecting pad 6 made of a woven cloth or the like, as shown in FIG.
Is provided. Instead of the water collecting pad 6, a porous cap made of ceramic or the like may be attached to the open end of the conduit 7. If necessary, a root cutting sheet (not shown) for preventing the roots from entering the pores of the water collecting pad 6 or the like may be applied, or the outside air surrounding the artificial culture medium 3 may be short-circuited to the water collecting tool 8. Appropriate measures may be taken to prevent the connection. Each conduit 7 of each water collecting tool 8 penetrates the side wall of the container 2 and protrudes outwardly, and then connects to one thin communication pipe 9, and the end of the connection pipe 9 has a cylindrical body 11, A head difference adjusting means 10 comprising an overflow pipe 12 inserted into the bottom surface of the cylindrical body 11 so as to be able to move up and down is connected below the cylindrical body 11. If the upper end height of the overflow pipe 12 is set lower than the height of the water collecting tool 6 by the head difference h, the water level in the cylinder 11 becomes higher due to the discharged liquid passing through the communication pipe 9 and the upper end height of the overflow pipe 12 becomes higher. After that, the water overflows into the overflow pipe 12 and is discharged out of the system. Therefore, the water level in the cylindrical body 11 is always kept constant, and each water collecting tool 8 has a water head difference h. Negative pressure suction will work. A correlation is established between the pF value of the rock wool medium and the above-mentioned head difference h. The relationship between the head difference h and the water content of the medium is experimentally determined, for example, as shown in FIG.
Therefore, if the head difference adjusting means 10 is set to a desired pF value or a value of h suitable for a desired medium moisture content,
Since a negative pressure suction force corresponding to h acts on each water collecting tool 6 to suck out water contained in the rock wool mat having a capillary potential lower than the negative pressure suction force, the water content of the culture medium can be maintained at a constant value determined by h. . In the example of FIG. 3, when the value of h is 15 cm in water column, the water content of the medium is maintained at 40%. Since the communication pipe 9 is filled with the sucked liquid and has no interruption, if the water content in each of the artificial culture media 3, 3,... The liquid is transferred through the conduit 7 of the artificial medium 3 having a low water content, and a correction for equilibrating the water content is performed. In the above example, since the content in the rock wool mat is sucked out by the negative pressure suction force corresponding to the head difference h, it takes a relatively long time. In order to respond to the request to extract the sample in a shorter time, the example shown in FIG. 4 may be used. In the example of FIG. 4, the cylinder 13 and the solenoid valve are provided at both ends of the communication pipe 9.
In the cylindrical body 13, an E1 electrode which issues a valve closing signal for the solenoid valve 14 when the water level in the cylindrical body 13 is lower than the lower limit level, and the water level in the cylindrical body 13 is at the upper limit level. An E2 electrode that issues a valve opening signal for the electromagnetic valve 14 when the above is obtained is provided. The difference in height between the lower end of the E1 electrode and the lower end of the E2 electrode is made small. The positional relationship between the solenoid valve 14 and the E2 electrode is such that the solenoid valve 14 is disposed further below the lower end of the E2 electrode. Now, when the liquid that has passed through the communication pipe 9 accumulates in the cylindrical body 13 and its water level comes into contact with the lower end of the E2 electrode,
The valve opening signal of the electrode valve 14 is issued, and the solenoid valve 14 is opened. Since the solenoid valve 14 is disposed further below the lower end of the E2 electrode as described above, the solenoid valve 14 has a sufficient head difference with respect to the artificial medium 3 and is drained at once. However, as described above, since the difference in height between the lower end of the E1 electrode and the lower end of the E2 electrode is small, the E1 electrode is immediately exposed to the air, and a valve opening signal of the electromagnetic valve 14 is issued, so that the electromagnetic valve 14 Opens. Then, the liquid that has passed through the communication pipe 9 accumulates in the cylindrical body 13 again. Thus, the above operation is repeated. The fact that the difference between the heights of the lower ends of the E1 electrode and the E2 electrode is small means that highly accurate control close to the head difference h in FIG. 1 can be performed. If the opening of the solenoid valve 14 is too abrupt, the illustration is omitted, but a valve may be provided in front of the solenoid valve 14.

【The invention's effect】

As described above, according to the present invention, since the head difference adjusting means is connected to the end of one communication pipe to which each water collecting device is connected, the excess liquid is simply suctioned from each artificial medium to lower the water content of the medium. Instead of the water head difference h, it is possible to manage by using a pF value that is correlated with the water head difference h. Furthermore, the negative pressure suction force equivalent to the water head difference h is evenly applied to each water tool to discharge the surplus water, as well as the water content. The liquid is transferred through the conduit to the artificial medium having a low mean, and the equilibrium of the moisture content variance between the artificial mediums can be automatically achieved. The head difference adjusting means may have a simple structure in which an overflow pipe is inserted into the bottom of a cylindrical body to which the end of the communication pipe is connected so as to be able to move up and down. The change adjustment of the head difference h is performed by raising and lowering the overflow pipe. This is extremely excellent in that it is possible to adjust the change of the water content of the culture medium at any time, since it is possible to achieve relatively high precision by itself. Further, when the head difference adjusting means is configured as in claim 3, it is possible to extract the head in a short time without lowering the accuracy.

[Brief explanation of figures]

FIG. 1 is a perspective view of a first embodiment of the apparatus for controlling the water content in an artificial medium according to the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a relation between the head difference h and the water content in the medium. FIG. 4 is a perspective view of the second embodiment, and FIG. 5 is a longitudinal sectional view of FIG. 1 ... stand, 2 ... receiving member, 3 ... artificial medium, 4 ...
Supply pipe, 5 ... Tube, 6 ... Water collecting pad, 7 ... Conduit, 8 ... Water collecting tool, 9 ... Communication pipe, 10 ... Head difference adjusting means, 11, 13 ... Cylindrical body, 12 ...... Overflow pipe, 14 ... Solenoid valve, E
1, E2 ... Electrode.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsuo Akamatsu 1 Tayacho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Yokohama Works, Sumitomo Electric Industries, Ltd. (72) Eiichi Sugano 9-18 Kamiyamacho, Shibuya-ku, Tokyo (56) References JP-A-63-36720 (JP, A) JP-A-63-4670 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) A01G 31 / 00

Claims (3)

(57) [Claims] A plurality of artificial artificial culture media are continuously laid in a receiving member, a water collecting device is disposed between each artificial medium and an abutting surface of the receiving member, and a conduit of each water collecting device is connected. Each of the connecting pipes is connected to one end of the connecting pipe, and a head difference adjusting means capable of providing an appropriate head difference lower than the water collecting tool is connected to an end of the connecting pipe. Leveling device. 2. The leveling device according to claim 1, wherein the head difference adjusting means comprises a cylinder connected to an end of the communication pipe, and an overflow pipe inserted into a bottom surface of the cylinder so as to be movable up and down. apparatus. 3. A head difference adjusting means, comprising: a cylindrical body and an electromagnetic valve communicating with both ends of a communication pipe; and an E1 electrode for issuing a valve closing signal of the electromagnetic valve when a water level in the cylindrical body becomes lower than a lower limit level. And, having an E2 electrode that emits a valve opening signal of the solenoid valve when the water level in the cylinder is equal to or higher than the upper limit level, while reducing the difference in height between the lower end of the E1 electrode and the lower end of the E2 electrode, 2. The apparatus for leveling uneven irrigation according to claim 1, wherein said solenoid valve is disposed further below a lower end of the electrode.