JPH0127695B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cultivation device used for hydroponic cultivation of crops.

[Prior art]

Advantages of hydroponic cultivation, which cultivates crops without using soil, are (1) easy labor-saving and automation; (2)
It has many advantages, such as no continuous cropping problems and (3) higher yields than soil cultivation, but on the other hand, because the nutrient solution is circulated, once pathogens are mixed into the nutrient solution, there is a risk of disease transmission. It has the disadvantage of high speed and great damage. Therefore, sterilization of the nutrient solution is one of the most important issues in hydroponic cultivation.

Therefore, conventional sterilizers of this type are shown in Figure 1A.
I found the one shown here. In the figure, 101 is a heating section, 102 is a cooling section, 103 is a heater, 104 is a fin, and 105 is a fluid.

Next, the operation of each of the above parts will be explained. The fluid 105 is, for example, milk, water, air, etc. used in the food processing industry, aquaculture industry, hospitals, etc., and the fluid 105 contains various pathogenic bacteria, molds, and the like. Therefore, in order to sterilize them, the fluid 105a is heated to a temperature sufficient for sterilization by the heater 103 etc. in the heating section 101, and then the fluid 105b is passed through the fins 104 of the cooling section 102 to the outside air. Heat is dissipated and cooled. The fluid 105c is then used in the next process.

However, the conventional sterilizer described above has a fluid 10
5 is heated, the energy required for this is simply radiated to the outside air in the cooling section 102, which results in a lot of waste, and the energy required for sterilization is extremely large.

FIG. 1B is a configuration diagram of a hydroponic cultivation apparatus having the above-mentioned heating sterilization mechanism.

In the figure, 1 is a crop, 2 is a cultivation tank, 3 is a nutrient solution tank, 4 is a nutrient solution, 5 is a nutrient solution circulation path connecting the cultivation tank 2 and the nutrient solution tank 3, 6 is a nutrient solution circulation pump,
7 is a heater, and 8 is a radiator.

Next, the operation will be explained. The nutrient solution 4 is continuously or intermittently circulated between the nutrient solution tank 3 and the cultivation tank 2 through the circulation path 5 by the nutrient solution circulation pump 6. At that time, the nutrient solution 4 is pumped up from the nutrient solution tank 3 by the pump 6, then heated to a temperature sufficient for sterilization by the heater 7, and then,
Heat is radiated to the surroundings by a radiator 8, and the temperature is cooled to a temperature suitable for crop cultivation and reaches the cultivation tank 2. Thereafter, the nutrient solution 4 repeats the above circulation.

Conventional hydroponic cultivation equipment with a heating sterilization mechanism is configured as described above, so it requires a large amount of energy to heat the nutrient solution, and even if the nutrient solution is cooled after heating and sterilization, the nutrient solution is The drawback was that the temperature could not be lowered below ambient temperature.

[Summary of the invention]

The present invention was made in order to eliminate the drawbacks of the conventional hydroponic cultivation apparatus having a heat sterilization mechanism as described above. It is an object of the present invention to provide a hydroponic cultivation apparatus that can reduce the energy required for heating the nutrient solution and also lower the temperature of the nutrient solution after cooling to below the ambient temperature by heating the nutrient solution in the endothermic part of the nutrient solution.

[Embodiments of the invention]

Various methods have been proposed for sterilizing the nutrient solution, such as heating sterilization, ultraviolet sterilization, and ozone sterilization, but the hydroponic cultivation apparatus of the present invention is constructed using a heating sterilization mechanism that is the most reliable and safest among them. has been done.

An embodiment of the present invention will be described below with reference to FIG. In the figure, numerals 1 to 6 indicate the same components as those with the same reference numerals in FIG. 1B.

In Fig. 2, 9 is a nutrient solution heating sterilization section, 10 is a nutrient solution cooling section, 11 is a mechanical compression type heat pump, 1
Reference numeral 2 denotes a heat radiation section of the heat pump, 13 a heat absorption section of the heat pump, 14 a compressor, 15 a pressure reducing valve, and 16 a refrigerant circulation path.

Next, the operation will be explained. The nutrient solution 4 is sucked up from the nutrient solution tank 3 by the pump 6, and exchanges heat with the heat radiation section 12 of the heat pump 11 in the nutrient solution heating sterilization section 9.
It is heated. Thereafter, the nutrient solution cooling section 10 exchanges heat with the endothermic section 13 of the heat pump 11 and is cooled to a temperature suitable for crop cultivation, and reaches the cultivation tank 2. Cultivation tank 2
The surplus nutrient solution is returned to the nutrient solution tank 3 via the nutrient solution circulation path 5.

In general, pathogens that attack the underground parts of crops die at a temperature of about 60°C. Therefore, the nutrient solution heating sterilization section 9 heats the nutrient solution 4 to the above-mentioned temperature of approximately 60°C. The energy used for heating and sterilizing the nutrient solution and cooling the nutrient solution requires only the power of the compressor 14, which is more energy-saving than the improved device shown in FIG. 1B. Furthermore, by setting the refrigerant evaporation temperature of the heat pump lower than the ambient temperature, it is also possible to lower the temperature of the nutrient solution entering the cultivation tank 2 below the ambient temperature.

In the above embodiment, the nutrient solution heating sterilization section 9 and the nutrient solution cooling section 10 were installed in the path from the nutrient solution tank 3 to the cultivation tank 2, but they can be installed at any position in the circulation system. Furthermore, as shown in the configuration diagram of another embodiment shown in FIG.
A nutrient solution heating sterilization section 9 and a nutrient solution cooling section 10 may be installed in the middle. In the figure, 6a is the separate nutrient solution circulation path 5a.
This is a nutrient solution circulation pump for use.

FIG. 4 is a configuration diagram showing another embodiment in which a two-stage heat pump is used, in which 14a and 14b are a low-temperature stage compressor and a high-temperature stage compressor, respectively;
15b are a low temperature stage pressure reducing valve, a high temperature stage pressure reducing valve, 16
a and 16b are a low temperature stage refrigerant circulation path, a high temperature stage refrigerant circulation path, 17a is a low temperature stage heat dissipation section, and 17b is a high temperature stage heat absorption section.

Incidentally, although the above description has been made regarding the case where a mechanical compression type heat pump is used as the heat pump, it goes without saying that it is also possible to use an absorption type heat pump, an electronic type heat pump, etc. based on other principles.

〔Effect of the invention〕

As described above, according to the present invention, the heat sterilization and cooling of the nutrient solution are performed using the same heat pump, so the energy required for heat sterilization can be extremely reduced, and the temperature of the nutrient solution can be kept lower than the ambient temperature. This has the effect of providing an ideal hydroponic system that can be lowered.

[Brief explanation of drawings]

Figure 1A is a configuration diagram of a conventional sterilization mechanism, Figure 1B
1 is a block diagram showing a hydroponic cultivation apparatus having the sterilization mechanism shown in FIG. It is a block diagram of the hydroponic cultivation apparatus which shows another Example. 1... Crop, 2... Cultivation tank, 3... Nutrient solution tank, 9... Nutrient solution, 5, 5a... Nutrient solution circulation path, 6,
6a... Nutrient circulation pump, 7... Heater, 8...
Heat radiator, 9... Nutrient solution heating sterilization section, 10... Nutrient solution cooling section, 11... Heat pump, 12... Heat radiating section,
13... Endothermic part, 14, 14a, 14b... Compressor, 15, 15a, 15b... Pressure reducing valve, 16, 1
6a, 16b...refrigerant circulation path, 17a...low temperature stage heat radiation section, 17b...high temperature stage heat absorption section. In addition, in the figure,
The same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. A heating sterilization section that heats and sterilizes a nutrient solution, and a cooling section that cools the nutrient solution heated in the heat sterilization section to a temperature suitable for crop cultivation. A hydroponic cultivation apparatus characterized in that heating of the nutrient solution in the thermal sterilization section and cooling of the nutrient solution in the cooling section are performed by the same heat radiating section and endothermic section of the same heat pump, respectively. 2. The hydroponic cultivation device is characterized by having a heating sterilization section and a cooling section in the nutrient solution circulation path that circulates the nutrient solution between the cultivation tank for cultivating crops and the nutrient solution tank for storing the nutrient solution. A hydroponic cultivation apparatus according to claim 1. 3. In a nutrient solution tank that circulates nutrient solution between a cultivation tank in which crops are grown and a nutrient solution tank that stores nutrient solution, the nutrient solution inside the nutrient solution tank is taken out, heated, sterilized, and cooled. 2. The hydroponic cultivation apparatus according to claim 1, further comprising a mechanism for returning the water to the tank. 4. The hydroponic cultivation apparatus according to claims 1 to 3, wherein the heat pump is a multistage heat pump.