JPH0662684A - Thermal sterilizer for liquid fertilizer for solution culture - Google Patents

Abstract

PURPOSE:To diversify the utilization of a thermal sterilizer for a liquid fertilizer used for solution culture. CONSTITUTION:The thermal sterilizer 10 is composed of a heating part 11, a heat exchange part 12 and a cooling part 13. A liquid fertilizer is passed from the first tank 21 for storing the liquid fertilizer before treatment through an inlet 16, introduced into a pump 14, further heated with the heat exchange part 12 having a water-water heat exchanger in the interior thereof, then heated with the heating part 11, sterilized and introduced into the heat exchange part 12 to exchange the heat therein and decrease the temperature thereof. The cooled liquid fertilizer is passed through the cooling part 13 and an outlet 17, stored in the second tank 22 and subsequently fed to a cultivation bed 24 with a pump 23. This sterilizer 10 is used for sterilizing and cooling, sterilizing and heating and sterilizing the cultivation bed in addition to the sterilizing.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the sterilization of liquid fertilizer for hydroponics.
The present invention relates to a heating / cooling device and a method of using the device.

[0002]

2. Description of the Related Art The applicant of the present invention has filed a patent application for a heat sterilizer for liquid fertilizer for hydroponics (Japanese Patent Laid-Open No. 3-1279).
No. 18), the invention relates to a liquid storage tank for storing liquid fertilizer (nutrient liquid) returning from the cultivation bed, a pump for feeding the liquid fertilizer in the liquid storage tank to a heat exchange pipe arranged in the heat exchange tank, and a liquid fertilizer. A heat exchange tank for storing and internally storing a water-to-water heat exchanger in which a heat exchange pipe is arranged in the liquid fertilizer, a lower part and an upper part are connected by piping, and heat is transferred by the outlet and piping of the heat exchange pipe. It is equipped with a heating tank connected to the upper part of the exchange tank and housing the heating means inside, a liquid supply tank connected to the lower part of the heat exchange tank by a pipe, and supplying liquid fertilizer to the cultivation bed through the pipe. In the water heat exchanger, the liquid fertilizer in the liquid storage tank and the liquid fertilizer heated and sterilized in the heating tank exchange heat.

[0003]

The above-mentioned device is actually in use, and there is no particular problem.
To make more effective use of the device as it is currently installed,
More specifically, it was considered that the apparatus had the functions of heating and cooling the liquid fertilizer supplied to the cultivation bed and sterilizing the cultivation bed itself.

[0004]

The apparatus of the present invention comprises a cultivation bed (2) from a second tank (22) through a pipe by a pump (23).
Liquid fertilizer is supplied to 4), and liquid fertilizer leaving the cultivation bed (24) is piped.
A heating and sterilizing apparatus for liquid fertilizer for nutrient culture, which is led to a first tank (21) via (20J), including a heating unit (11), a heat exchange unit (12) and a cooling unit (13). The liquid fertilizer stored in the tank (21) is installed in the heat exchange part (12) through the inlet (16) via the pump (14), the pipe (20A) and the pipe (20A), and the water-to-water heat exchanger (12A) is installed.
A four-way valve (15) for switching in three directions is attached to the pipe (20K) connected to the outlet (17) by connecting the other to the heating part (11) by the pipe (20B), and the four-way valve Outlet (17) from heating section (11) through heat exchange section (12), cooling section (13) by (15)
To the first path, which is connected by pipes (20C), (20D), and (20G), and through the heating section (11) and part of the heat exchange section (12) to the outlet (1
7) 2nd path connected to the piping by (20C, 20E) and heating section
The flow path should be switched from (11) to the third path connected to the outlet (17) by the pipe (20F), and the liquid fertilizer passing through the outlet (17) should be stored in the second tank (22). Is characterized by.

In the method for sterilizing and cooling liquid fertilizer of the present invention, liquid fertilizer for hydroponics is introduced from the first tank (21) to the heat exchange section (12) through the inlet (16) and heated there, and the heating is performed. The heated liquid fertilizer is further heated and sterilized by the heating unit (11), the heated liquid fertilizer is heat-exchanged by the heat exchange unit (12) to lower the temperature, and the cooled liquid fertilizer is cooled by the cooling unit (13), The cooled liquid fertilizer is stored in the second tank (22) through the outlet (17) and then supplied to the cultivation bed (24).

In the method for sterilizing and heating liquid fertilizer of the present invention, the liquid fertilizer for hydroponics is introduced from the first tank (21) to the heat exchange section (12) through the inlet (16) and heated there, and the heating is performed. The heated liquid fertilizer is further heated and sterilized by the heating unit (11), the heated liquid fertilizer is partially heat-exchanged in the heat exchange unit to lower the temperature to a predetermined temperature, and the cooled liquid fertilizer is cooled ( It is characterized in that it is stored in the second tank (22) through the outlet (17) without being cooled in 13) and then supplied to the cultivation bed (24).

Further, in the method for sterilizing a cultivation bed for hydroponic culture of the present invention, liquid fertilizer for hydroponic culture is fed from the inlet (16) to the heat exchange section (1).
2) through the heating section (11), heated to a predetermined temperature in the heating section, the liquid fertilizer heated to the predetermined temperature outlet (17)
It is characterized in that it is stored in the second tank (22) via the above, and the heated liquid fertilizer is supplied from the second tank (22) to the cultivation bed (24) and used for sterilization of the cultivation bed.

[0008]

The device 10 of the present invention includes a heating part 11, a heat exchanging part 12, and a cooling part 13. The device 10 can switch pipes by using a four-way valve 15, and the heat exchanging part can be changed.
12 is the first heating of the liquid fertilizer entering from the first tank 21, the heating unit 11 is the second heating, the second heating liquid fertilizer came from the inlet 17 at the heat exchange unit 12. The liquid fertilizer is heated to lower the temperature, and the liquid fertilizer thus cooled is stored in the second tank 22 with or without being cooled in the cooling unit 13, and the liquid fertilizer stored in the second tank 22 is supplied to the cultivation bed. Has become.

There are three modes of using the above-mentioned apparatus 10. For sterilization and cooling, liquid fertilizer is cooled by the cooling unit 13
To about 20 ° C. and supply it to the cultivation bed 24 to maintain the cultivation bed at an appropriate temperature of about 25 ° C.

In order to use the liquid fertilizer for sterilization and heating, the liquid fertilizer heated in the heating section 11 is heated to a predetermined temperature (approximately in the heat exchange section).
Cultivate bed without cooling it to 30 ℃)
Since it is supplied to 24, the liquid fertilizer is not only sterilized but also used for heating the cultivation bed.

In the third embodiment of the present invention, the heating unit 11
The liquid fertilizer is heated to about 60 ° C. with the second tank 22 and is supplied to the cultivation bed 24 where there is no crop, thereby sterilizing the pathogenic bacteria present in the cultivation bed 24.
The temperature of 60 ° C. is sufficient for sterilization when it takes about 60 minutes, and since it is a temperature that does not cause softening of the plastic material forming the cultivating bed, sterilization is realized without damaging the cultivating bed 24. is there.

[0012]

The present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 is a schematic diagram showing the basic arrangement of the device of the present invention. In the figure, the part surrounded by a chain double-dashed line and shown by reference numeral 10 is the device according to the present invention, 11 is a heating part, 12 is a heat exchange part, 13 Is a cooling unit, 14 is a pump for flowing liquid fertilizer into the apparatus 10, 15 is a four-way valve, 16 is an inlet, 17 is an outlet, 20A, 20B ... 20K is piping,
21 is a first tank for storing liquid fertilizer before treatment (also called nutrient solution), 22 is a second tank for storing liquid fertilizer after treatment, 23 is a pump for circulating the liquid fertilizer to the cultivation bed, 24 is a cultivation bed, 25 Is a crop. The cultivation bed 24 has 20J of piping.
Alternatively, the discharge port 26 can be arranged.

The heating part 11 is a part for further heating the liquid fertilizer sent from the inlet 16 to the heat exchange part 12 by the pump 14 and heated in the heat exchange part, and is known for heating such as an electric heater or an oil-fired burner. The heating means is used.

The heat exchange section 12 is a section containing a water-to-water heat exchanger 12A manufactured and sold by the present applicant, and the liquid fertilizer sent from the inlet 16 is heated by the heating section 11 in the heat exchange section 12. The liquid fertilizer is heated by heat exchange with the liquid fertilizer, and further heated in the heating unit 11 to be sterilized, while the liquid fertilizer further heated in the heating unit 11 exchanges heat with the liquid fertilizer supplied by the pump 14 in the heat exchange unit 12. To lower the temperature.

When it is required to cool the liquid fertilizer, the heat exchange section 12
Liquid fertilizer supplied from the pipe 20D is cooled by the cooling unit 13. The cooling unit 13 cools the liquid fertilizer by using a cooler or groundwater, or when the outside air temperature is low, heat is exchanged with the outside air by a radiator.

The heated or cooled liquid fertilizer is stored in the second tank 22 from the outlet 17 through the pipe 20H, and then the pump.
It is supplied to the cultivating bed 24 by 23, flowed in the cultivating bed in the direction of the arrow 1, and then returned to the first tank 21.

The four-way valve 15 is manually or automatically switched.
There are three types of switching of the pipes. In the case of "normal" shown in FIG. 1, the liquid fertilizer is heat-sterilized and then heat-exchanged to lower the temperature, and is sent to the second tank 22 as it is or after further cooling. FIG. 1 shows an example of cooling by the cooling unit 13.

In the case of "warming" shown in FIG. 1, heat sterilization of the liquid fertilizer is followed by heat exchange up to the middle of the water-to-water heat exchanger 12A of the heat exchange section 12, and the liquid fertilizer is shown in a warm state by a broken line 20E. It is sent to the four-way valve 15 through the path and then supplied to the second tank 22 through the pipe 20K.

In the case of "bed sterilization" shown by the alternate long and short dash line in FIG.
And then supplied to the second tank 22 from which the cultivation bed 24
Is supplied to.

As can be understood from the above description, the apparatus shown in FIG. 1 has the following three paths. 1st route Heating part 11 → piping 20C → heat exchange part 12 → piping 20D → cooling part 13
→ Piping 20G → Four-way valve 15 → Piping 20K → Outlet 17 Second path heating part 11 → Piping 20C → Part of heat exchange part 12 → Piping 20E → Four-way valve 15 → Piping 20K → Outlet 17 Third path heating part 11 → Piping 20F → 4-way valve 15 → Piping 20K → Exit 17

The device of FIG. 1 can only be used for the purpose of sterilizing liquid manure. An example of this use is shown in FIG. 2, which utilizes the heat exchange section 12 and the heating section 11 to perform heat sterilization of liquid fertilizer. It should be noted that the water-to-water heat exchanger 12A is omitted in FIGS. 2 and below for the sake of simplicity. 20 ° C at inlet 16
The liquid fertilizer is sent to the heat exchange section 12 by the pump 14 through the pipe 20A to be heated, and when it exits the heat exchange section 12, it is heated to 75 ° C and is sent to the heating section 11 through the pipe 20B. The liquid fertilizer that has been heated to ℃, enters the heat exchange unit 12 via the pipe 20C, and exchanges heat with the liquid fertilizer at 20 ° C in the heat exchange unit.The temperature in the cultivation bed is 25 ° C, so the liquid fertilizer is cooled to 25 ° C. Pipe 20D,
2nd tank from outlet 17 via 20G, four-way valve 15, piping 20K
Guided to 22. This use example is the same as the use form of the invention of the above-mentioned patent application. In this case, the cooling unit 13 arranged between the pipes 20D and 20G is turned off, and the liquid fertilizer only passes through.

In this use example, the temperature of the liquid fertilizer at the outlet 17 is the same as that at the inlet 16
The temperature rises slightly (5-10 ° C) above the liquid fertilizer temperature. The rate of increase depends on the capacity of the heat exchanger, but heat exchange near 100% is practically impossible. Due to the temperature rise of 5 to 10 degrees Celsius, when there is a certain amount of heat radiation from the cultivation bed 24, such as in the winter season, or a small amount of liquid fertilizer to be processed as in rock wool cultivation, the temperature of the liquid fertilizer may affect the cultivation bed. Use this method for smaller cases.

The first embodiment of the present invention is the case of sterilization cooling shown in FIG. 3, and in this method, after heat sterilization is performed using the heat exchanging section 12 and the heating section 11, it is cooled by the cooling section 13. I do. In summer, the outside temperature is high and the temperature of the cultivation bed tends to rise, so that the load on the cooling unit 13 increases.

As in the case of FIG. 2, the liquid fertilizer coming out from the heat exchange section 12 at a temperature of 25 ° C. enters the cooling section 13 at a temperature of 25 ° C. through the pipe 20D and is cooled to 20 ° C. there. Piping 20G
, Four-way valve 15, piping 20K, outlet 17, piping 20H to the second
Stored in tank 22, then pump 23 to grow bed
Supplied to 24. The liquid fertilizer not only feeds the crop 25 but also keeps the temperature in the cultivation bed 24 at a suitable temperature of about 25 ° C.

The second embodiment of the present invention is an example of sterilization heating shown in FIG. The heat exchange section 12 and the heating section 11 are used to heat and sterilize the liquid fertilizer, but a part of the water-to-water heat exchanger of the heat exchange section 12 is not used and the liquid fertilizer is grown in a state in which the temperature is high to some extent. Supply to. This method is used when the temperature of the cultivation bed tends to decrease, such as in the severe winter season.

The process until the liquid fertilizer at 80 ° C. is supplied to the heat exchange unit 12 is the same as in the case of FIGS. 2 and 3, but in the example of FIG. 4, liquid fertilizer is fed from the middle of the heat exchanger of the heat exchange unit. The liquid fertilizer coming out of the heat exchanger has a temperature of about 30
Set the liquid fertilizer outlet so that the temperature becomes ℃.

Further, the liquid fertilizer at 30 ° C. is stored in the second tank 22 at a temperature of 30 ° C. through the pipe 20E, the outlet 17, and then the pipe.
It is supplied to the cultivation bed 24 through 20I to heat the cultivation bed and feed the crop 25.

The third embodiment of the present invention is the cultivation bed sterilization shown in FIG. The liquid fertilizer is sterilized by heating using only the heating unit 11, and the liquid fertilizer is supplied to the cultivation bed at a high temperature and sterilized. This method is carried out to kill pathogenic bacteria that have adhered to the cultivation bed when there is no crop in the cultivation bed.

In the hydroponic culture, when even a small amount of pathogenic bacteria enters the liquid fertilizer, the liquid fertilizer is supplied to the cultivation bed at a temperature suitable for the pathogenic bacteria at 20 ° C to 25 ° C. Proliferate and spread inside. The liquid fertilizer is sterilized for the purpose of preventing it, but the sterilization of the cultivation bed is performed by selecting the time when no crop is cultivated in the cultivation bed in order to eliminate the pathogenic bacteria.

Conventionally, the sterilization of the cultivation bed has been performed by either a method using a drug or a method using steam. However, recently, the use of drugs is considered to be unfavorable from the viewpoint of the effects on crops and the environment. Although the use of steam does not have the above-mentioned effect, it requires a device such as a boiler to prepare the steam, and there is a risk that the user will be burned, which is a problem in practice.

Therefore, in the present invention, as shown in FIG. 5, the liquid fertilizer heated to 60 ° C. in the heating section 11 is directly piped.
20C, pipe 20F indicated by alternate long and short dash line, four-way valve 15, pipe 20
Take K, exit 17 directly to the second tank 22, then the second tank
The liquid fertilizer at 60 ° C. is supplied from 22 to the pump 23 through the pipe 20I to the cultivation bed 24 where no crop exists.

There are two reasons for heating liquid fertilizer to 60 ° C. The first is that most of the bacteria that pose a problem in cultivation can be sterilized even when liquid fertilizer at 60 ° C is used for 60 minutes.
Secondly, most of the materials generally used in the field of liquid fertilizer cultivation are plastic materials, and since these plastic materials often soften above 60 ° C, the temperature of liquid fertilizer supplied to the cultivation bed is 60 ° C. The degree is the upper limit.

In the above-described embodiments, the liquid fertilizer is only supplied to the cultivating bed 24, but in any of the embodiments, the liquid fertilizer is supplied from the cultivating bed 24 to the pipe 20.
After returning to the 1st tank 21 using J, the above-mentioned process is repeated. The operation and circuit of each part are switched and used according to the purpose of use, but it is possible to automate by incorporating an electric valve, a thermostat, or the like.

In the examples of FIGS. 2 to 4 described above, the liquid fertilizer used in the cultivation bed 24 passes through the pipe 20J and the first tank 2
Although it has been returned to 1, it may be configured to discharge to the outside from the discharge port 26 instead. When and under what conditions discharge is determined by the usage of the cultivation bed, but the discharge port 26 is useful when replacing the liquid fertilizer that has been used with another liquid fertilizer. The discharge port 26 is equipped with a valve at the connecting part of the cultivation bed of the pipe 20J, and the liquid fertilizer is piped by operating this valve.
Instead of 20J, it can be configured to be discharged to the outside.

Table 1 shows the modes of use of the apparatus of the present invention described above. In the column of heat exchange section in Table 1, the terms primary side (low temperature side) and secondary side (high temperature side) are from pipe 20A and pipe 20C to the water-to-water heat exchanger 12 respectively.
The side that enters A.

[0036]

[Table 1]

[0037]

As described above, according to the present invention,
By using one device for hydroponic cultivation, only four sterilization modes, sterilization nutrient solution cooling and sterilization nutrient solution heating, and bed sterilization can be used. The effect of expanding the use of hydroponic cultivation using the was obtained.

[Brief description of drawings]

FIG. 1 shows the arrangement of the device according to the invention.

FIG. 2 is a diagram showing one usage state of the apparatus of FIG.

FIG. 3 is a diagram of a first embodiment of the present invention.

FIG. 4 is a diagram of a second embodiment of the present invention.

FIG. 5 is a diagram of a third embodiment of the present invention.

[Explanation of symbols]

 10 Device of the present invention 11 Heating part 12 Heat exchange part 12A Water-to-water heat exchanger 13 Cooling part 14 Pump 15 Four-way valve 16 Inlet 17 Outlet 20A, 20B ... 20K Piping 21 First tank 22 Second tank 23 Pump 24 Cultivation bed 25 Crop 26 Outlet

Claims (5)

[Claims] A liquid fertilizer is supplied from a second tank (22) to a cultivation bed (24) by a pump (23) through a pipe, and the cultivation bed is
The liquid fertilizer exiting (24) is a heating and sterilizing device for liquid fertilizer for hydroponic cultivation, which is guided to the first tank (21) through the pipe (20J), and includes a heating unit (11), a heat exchange unit (12) and a cooling unit. A water pair provided in the heat exchange part (12) including the part (13), the liquid fertilizer stored in the first tank (21) through the pump (14), the pipe (20A) and the inlet (16). A four-way valve that connects to one side of the water heat exchanger (12A), connects the other side to the heating part (11) by the pipe (20B), and switches to the pipe (20K) connected to the outlet (17) in three directions ( 15) is attached, and the four-way valve (15) connects the heating section (11) to the heat exchange section (12), the cooling section (13) to the outlet (17) through the pipes (20C), (20D), (20).
G) and the first path connected from the heating part (11) to the heat exchange part
The second path that passes through a part of (12) and is connected to the outlet (17) by piping (20C, 20E), and the second path that is connected from the heating part (11) to the outlet (17) by piping (20F). A heating and sterilizing apparatus for liquid fertilizer for hydroponic culture, characterized in that the flow path is switched to three paths, and the liquid fertilizer that has passed through the outlet (17) is stored in the second tank (22). 2. The liquid fertilizer for hydroponics is introduced from the first tank (21) through the inlet (16) to the heat exchange section (12) and heated there, and the heated liquid fertilizer is heated (11). Further sterilized by heating, the heated liquid fertilizer is heat-exchanged in the heat exchange unit (12) to lower the temperature, the cooled liquid fertilizer is cooled in the cooling unit (13), and the cooled liquid fertilizer is exited (17). A method for sterilizing and cooling liquid fertilizer for hydroponic culture, characterized in that the liquid fertilizer is stored in the second tank (22) through the above and then supplied to the cultivation bed (24). 3. The liquid fertilizer for hydroponics is introduced from the first tank (21) through the inlet (16) to the heat exchange section (12) and heated there, and the heated liquid fertilizer is heated (11). Further sterilized by heating, the heated liquid fertilizer is partially heat-exchanged in the heat exchange unit to lower the temperature to a predetermined temperature, and the cooled liquid fertilizer is not cooled in the cooling unit (13) and exits.
After being stored in the second tank (22) via (17), the cultivation bed (2
4) to sterilize liquid fertilizer for hydroponics
Heating method. 4. The method according to claim 2, wherein the liquid fertilizer used in the cultivation bed (24) is discharged from the discharge port (26). 5. The heat exchange section from the inlet (16) for liquid fertilizer for hydroponics
It is led to the heating part (11) through (12), heated to a predetermined temperature in the heating part (11), and the liquid fertilizer heated to the above predetermined temperature is passed through the outlet (17) to the second tank (22). A method for sterilizing a cultivation bed for hydroponics, which comprises storing and supplying heated liquid fertilizer from the second tank (22) to the cultivation bed (24) for use in sterilizing the cultivation bed.