JPS6324828A - Liquid fertilizer irrigation control apparatus for hydroponics - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a method for applying liquid fertilizer water to plants hydroponically cultivated in an artificial medium in a manner appropriate to the amount of transpiration. This invention relates to a liquid fertilizer irrigation control device for hydroponic cultivation that allows irrigation to continue until water is discharged.

<Conventional technology> When performing hydroponic cultivation using an artificial medium such as a rock wool mat, the amount of culture solution absorbed by each plant is measured, and the culture solution corresponding to that amount is supplied to each plant. It would be ideal if it could be done, but in reality, there are technical and
This is difficult to implement due to economic reasons. Therefore, it is customary to measure the amount of transpiration at a specific location under the same growth conditions to represent a large bed area where many plants are grown, and to manage overall irrigation based on the measurement results.

An example of a device in this case is that a recess is formed in the lower central part of the rock wool bed, and two electrodes for detecting the water level are attached to the recess, along with a puddle of excess culture medium. As the crops transpire, the liquid in the pool is sucked up in the capillary tubes of the bed, and an electrode at a lower position senses that the water has dropped to a predetermined level and issues an irrigation start signal, and irrigation begins again. When excess culture fluid accumulates in the reservoir, an electrode at a high position senses that the permeability has dropped to a predetermined level and issues an irrigation stop signal.

The above-mentioned concave part may not necessarily represent the whole, depending on its condition, so
An example is also known in which a stainless steel tray with a liquid reservoir is placed horizontally, a capillary mat is spread on the inner surface of the tray, and a rock wool bed is formed on top of the capillary mat.

The capillary mat is used to make it possible to suck up excess culture solution accumulated in the liquid pool of the metal tray to the bed.

In addition, the present applicant has set an irrigation stop signal in order to continue irrigation until a predetermined amount of liquid has been discharged, so that waste products from the roots are not allowed to survive in the medium and are removed by washing them off each time irrigation is performed. A separate application has been filed for a device that uses a timer instead of electrodes that emit water, allowing the duration of irrigation to be set arbitrarily.

<Problems to be Solved by the Invention> As mentioned above, using a timer to control the amount of liquid to be discharged based on the irrigation duration increases equipment costs compared to electrodes, and also causes problems such as power outages. In addition to the above-mentioned timer, this is a safety device that once returns the water level in the liquid pool to normal when the original control operation resumes after the accident has been corrected after an uncontrollable condition continues. This requires sub-timers, control circuits, etc., and tends to make the device complicated and sophisticated.

<Means for Solving the Problems> In order to eliminate such drawbacks, the present invention is based on a system in which plants are grown hydroponically in an artificial medium laid on the inner surface, and excess water is collected in a pool formed in the longitudinal direction. A series of electrodes are installed to receive the overflow liquid from the overflow pipe attached to the side of the liquid pool, and an electrode that issues an irrigation start signal when contact with the liquid in the liquid pool is cut off. , by providing a means for making it possible to arbitrarily set the amount of accumulated liquid in the tank and to discharge it all at once when the amount of accumulated liquid is reached, and an electrode that comes into contact with the discharged liquid from the receiving tank to issue an irrigation stop signal. This makes it possible to perform low-cost and simple irrigation control based on the liquid standard, and it is possible to perform watering in small amounts and many times, which is desirable for plant growth.

<Examples> The present invention will be explained by examples shown in the drawings as follows.

In FIG. 1, 1 is a stainless steel tray,
A liquid reservoir 2 having a V-shaped cross section is formed at the center of the bottom surface over the entire length in the longitudinal direction.

Capillary pines 1 to 3 are laid out on the inner surface of the tube (including the liquid reservoir 2), and rock wool pines 1 to 3 are placed thereon as an artificial medium 4, and the plants 5 are placed in a nutrient solution according to the usual method. Cultivate. Although not shown in the drawings, if necessary, sheaths 1 to 1 for root cutting are placed on top of the capillary mat 3. A liquid reservoir 2 in which excess irrigation water accumulates passes through one side plate of the tray 1 to form an outwardly protruding portion 6, and an end plate 7 provided with an overflow pipe 8.
It ends with The upper limit of the water level of the liquid reservoir 2 is determined by the installation position of the overflow pipe 8. The upper portion of the outwardly protruding portion 6 is open, and a water level measuring electrode 9 is mounted thereon, which is movable up and down with a threaded structure shown in FIG. Electrode 9 functions as earth electrode 1
5, the amplification circuit amplifies the electrical change that occurs when the tip of the electrode 9 leaves the liquid surface, and uses this as an irrigation start signal. The terminal plate 9a has a structure that does not loosen even when the electrodes are moved up and down. The overflow liquid from the overflow pipe 8 is received by the receiver 1if'I.
It is stored in O. One feature of this invention is that this receiving tank 1
0 has a point C in which the means 11 is modified so that the amount of liquid stored in the tank can be arbitrarily set and can be discharged at once when the amount of stored liquid is reached. As a specific example of such means 11, in the example shown in FIG. 1, a siphon tube 11a is used in which the height of the siphon can be changed. In this example, the liquid discharged all at once from the receiving tank 10 once receives the discharge tank 12, and its discharge from the discharge tank 12 is restricted by a small-diameter discharge pipe 13 provided in the discharge tank 12. Therefore, at the initial stage when the discharge tank 12, which was initially empty, receives the liquid discharged all at once from the receiving tank 10, the water level rises suddenly at times, and the water level drops to each part of the tank, Eventually it becomes empty again. Using this discharge tank 12, an electrode 14 having the same structure as the electrode 9 is attached.

Next, we will move on to an explanation of the operation when the above configuration is adopted. now,
It is assumed that the liquid reservoir 2 is filled with surplus culture liquid at a water level determined by the overflow pipe 8. Since the liquid in the liquid pool 2 is sucked up as the plants 5 transpire, a time will come when the liquid level will separate from the tip of the electrode 9.

The electrical signal at this time is amplified and sent to a control circuit to start irrigation. In this way, although not shown, the culture solution is supplied all at once from the irrigation tubes provided at each cultivation location of each plant 5. As the supply continues, overflow from the hot flow pipe 8 begins, and the overflow liquid flows into the receiving tank 1.
The water level remains at 0 and gradually rises. When the water level exceeds the height of the siphon, the liquid flows all at once into the siphon tube 1.
It is discharged from 1a to the discharge tank 12.

Since the discharge pipe 13 of the discharge tank 12 that receives the liquid has a small diameter as described above, the liquid remains in the discharge tank 12 without being drained away.

Therefore, if the electrode 14 is deeply inserted to near the bottom of the discharge tank 12, the liquid surface will come into contact with the electrode 14 almost at the same time as discharge is performed by the action of the siphon tube 11a. The electrical signal obtained at this time is amplified and sent to a control circuit to stop irrigation. In this way, irrigation control based on liquid volume is achieved.

In the above-mentioned siphon tube 11a, the amount to be discharged at once can be arbitrarily set by extending it high as shown by the dashed line in FIG. However, such means 11 is a siphon tube 1.
The method is not limited to 1a, but may be based on the principle of Shishi-Odoshi shown in FIG. That is, the receiving tank 10
is rotatably provided on one side of the pivot point 11b, and a weight 11C is provided on the opposite side so that it can be set at any position. Even in this case, the liquid accumulated in the receiving tank 10 can cause the weight 11 to
When the equilibrium state with C is disrupted, it falls over and is ejected all at once, and after ejection, it returns to its original state by the action of the weight 11c. Further, the amount of liquid discharged can be increased or decreased depending on the set position of the weight 11c.

Furthermore, although the discharge tank 12 is provided in the embodiment described above, the installation of the discharge tank 12 is not essential, and can be omitted as long as the discharge from the receiver 19i10 can be reliably detected with the electrode 14. .

<Effects of the Invention> According to the configuration described above, even if all the liquid in the liquid reservoir 2 is consumed as a result of an uncontrollable state due to an accident during a power outage, as soon as the accident is corrected, Irrigation is started by the action of the electrode 9 that is in contact with the air, excess water is accumulated up to the upper limit water level determined by the installation position of the overflow pipe 8, and irrigation is finished when the predetermined amount of overflow liquid is released. The system will return to a normal state, and there will be no need to use the conventional sub-timer.

Moreover, since the means 11 is provided which allows the amount of accumulated liquid in the receiving tank 10 to be arbitrarily set and which allows the liquid to be discharged at once when the amount of accumulated liquid is reached, the amount to be discharged out of the system each time irrigation can be changed as desired. By watering, waste products from the roots can be washed away, and together with the movement of the electrode 12, preparations for the next cycle are quickly completed.

Therefore, by setting the electrode 9 to be lower than the upper limit water level determined by the set position of the overflow pipe 8, the culture medium 4
It is possible to perform watering as many times as possible to prevent changes in water content and concentration in the root zone, as well as to prevent staining of the rhizosphere, using a simple and inexpensive device.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view of the liquid fertilizer irrigation control device for hydroponic cultivation according to the present invention, FIG. 2 is a sectional view showing the structure of the electrode, and FIG.
This figure is a sectional view of the siphon tube shown in FIG. 1, and FIG. 4 is a diagram showing another example in place of the siphon tube. 1...Tray, 2...Liquid pool, 3...Capillary mat, 4...Artificial medium, 5...Plant, 8...
Overflow pipe, 9.14... Electrode, 10... Receiving tank, 11.
...Means that can arbitrarily set the amount of accumulated liquid in the receiving tank and allow it to be discharged at once when the amount of accumulated liquid is reached.

Claims (1)

[Scope of Claims] 1. Plants (5) are hydroponically cultivated in an artificial medium (4) laid on the inner surface, and excess water is collected by liquid puddles (2) formed in the longitudinal direction.
A tray (1) is installed in series to collect the overflow liquid from the overflow pipe (8) attached to the side of the liquid pool (2). ), an electrode (9) that emits an irrigation start signal when contact with the liquid in the reservoir tank (10) is cut off, and means ( 1
1), and an electrode (14) that comes into contact with the liquid discharged from the receiving tank (10) to issue an irrigation stop signal. 2. Means (11) for making it possible to arbitrarily set the amount of accumulated liquid in the receiving tank (10) and to discharge it all at once when the amount of accumulated liquid is reached.
The liquid fertilizer irrigation control device for hydroponic cultivation according to claim 1, wherein is a siphon pipe (11a) attached to the bottom surface of the receiving tank (10) to make the height of the siphon variable.