PLANT CULTIVATION APPARATUS

Abstract

A plant cultivation apparatus comprising a cultivation box which has a hollow rhizosphere portion for hanging a root of a cultivation plant, wherein: the cultivation box is constructed by detachably combining an upper panel and a lower panel; a bottom wall of the lower panel is provided with a waste liquid port and a trough-shaped gutter is detachably installed below the bottom wall of the lower panel over an entire length in a length direction; the upper panel is provided with nozzle-mounting holes at intervals in the length direction; a nozzle for spraying nutrient solution is inserted into each of the nozzle-mounting holes and hung in the rhizosphere portion; the upper panel is provided with planting holes for the cultivation plant; and a root of the cultivation plant is inserted into the planting hole and hung in the rhizosphere portion, to which the nutrient solution is sprayed from the nozzle.

Claims

1. A plant cultivation apparatus comprising a cultivation box which has a hollow rhizosphere portion for hanging a root of a cultivation plant and in which nutrient solution is sprayed in a mist state in the rhizosphere portion, wherein: the cultivation box is constructed by detachably combining an upper panel and a lower panel; a bottom wall of the lower panel is provided with a waste liquid port and a trough-shaped gutter is detachably installed below the bottom wall of the lower panel over an entire length in a length direction; the upper panel is provided with nozzle-mounting holes at intervals in the length direction; a nozzle for spraying nutrient solution is inserted into each of the nozzle-mounting holes and hung in the rhizosphere portion; the upper panel is provided with planting holes for the cultivation plant; and a root of the cultivation plant is inserted into the planting hole and hung in the rhizosphere portion, to which the nutrient solution is sprayed from the nozzle.

2. The plant cultivation apparatus according to claim 1, wherein: the lower panel has inclined side walls on both sides in a width direction, that are formed inclined in an upward spreading direction; the upper panel has inclined side walls on both sides in the width direction, that are formed inclined in a downward spreading direction; the cultivation box is formed into any one of shapes of wide, narrow, shallow and deep by changing a width or height of the lower panel and the upper panel; the nozzle-mounting hole is provided on a top surface between the inclined side walls on both sides of the upper panel; and the planting holes are provided on the inclined side wall in a staggered arrangement.

3. The plant cultivation apparatus according to claim 1, wherein: the lower panel and the upper panel respectively have vertical side walls on both sides in a width direction; a top surface of the upper panel and a bottom surface of the lower panel are horizontal; the cultivation box is formed into any one of shapes of wide, narrow, shallow and deep by changing a width or height of the lower panel and the upper panel; the one nozzle-mounting hole is provided on the top surface of the narrow upper panel, or the plurality of nozzle-mounting holes are provided at intervals on the top surface of the wide upper panel; and the planting holes are provided at positions sandwiching the nozzle-mounting hole.

4. The plant cultivation apparatus according to claim 1, wherein: a receiving plate portion is provided so as to protrude outward from an upper end of each side wall in a width direction of the lower panel, and a fitting portion is provided on the receiving plate portion; a mounting portion is provided so as to protrude outward from a lower end of each side wall in the width direction of the upper panel, and a fitted portion is provided on the mounting portion; and the mounting portion of the upper panel is put on the receiving plate portion of the lower panel to fit the fitting portion to the fitted portion, or an intermediate panel for increasing volume of the rhizosphere portion is interposed between the side walls of the upper panel and the lower panel on both sides wherein connection plate portions protruding outward at an upper end and a lower end of the intermediate panel are respectively abutted and connected with the mounting portion and the receiving plate portion.

5. The plant cultivation apparatus according to claim 1, wherein: a nutrient solution supply pipe is inserted into the nozzle-mounting hole of the upper panel and hung in the rhizosphere portion; a pipe that branches on both sides in the length direction is provided at a lower end of the nutrient solution supply pipe; the nozzle for spraying forward and the nozzle for spraying rearward are provided at both front and rear ends of the branch pipe; the nozzles are disposed between the plurality of cultivation plants arranged side by side in the length direction; the nutrient solution supply pipes are connected to a main nutrient solution supply pipe at intervals in the length direction; and the main nutrient solution supply pipe is installed and piped on an upper side of the upper panel.

6. The plant cultivation apparatus according to claim 1, wherein a hollow conical nozzle which sprays a swirling flow or a pin jet nozzle which sprays by impinging a straight rod flow on a pin is used as the nozzle for spraying the nutrient solution.

7. The plant cultivation apparatus according to claim 1, further comprising a generator that operates in a power failure or a battery that is supplied with power from a solar power generation panel for charging.

8. The plant cultivation apparatus according to claim 1, further comprising a CO.sub.2 supply device that supplies CO.sub.2 to the rhizosphere portion.

9. The plant cultivation apparatus according to claim 1, further comprising an abnormality notification device that raises an alarm in detecting any one of: power failure and abnormal occurrence of an electric component provided on a nutrient solution supply means to the nozzle; abnormal water level occurrence in a fertilizer tank storing the nutrient solution; disconnection occurrence of a CO.sub.2 sensor installed on the rhizosphere portion; and disconnection occurrence of a solar radiation sensor.

10. The plant cultivation apparatus according to claim 1, further comprising: a clarifying device that sterilizes a waste liquid collected through the waste liquid port by using UV, ozone or a photocatalyst; an automatic cleaning filter device that filtrates a purified waste liquid; and a pipe returning from the automatic cleaning filter device to a fertilizer tank.

11. The plant cultivation apparatus according to claim 1, further comprising a chiller device that prevents overheating of a nutrient solution stored in a fertilizer tank.

12. The plant cultivation apparatus according to claim 1, further comprising a controller that automatically controls at least one of a CO.sub.2 concentration in the rhizosphere portion and a spray cycle of the nutrient solution, depending on a growth stage of the plant and an amount of solar radiation.

13. The plant cultivation apparatus according to claim 1, further comprising a control means that controls an EC concentration and pH of the nutrient solution to be sprayed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] FIG. 1(A) shows a schematic perspective view of a cultivation facility of a plant cultivation apparatus according to a first embodiment of the present invention, and FIG. 1(B) shows a perspective view of a cultivation box installed in the cultivation facility.

[0058] FIG. 2(A) shows a side view of a cultivation box in a state of being held by a stand, FIG. 2(B) shows an enlarged side view of the cultivation box, and FIG. 2(C) shows a cross-sectional view of the cultivation box in a length direction thereof.

[0059] FIG. 3 shows an upper panel of a cultivation box, wherein FIG. 3(A) is a plan view, FIG. 3(B) is a perspective view, and FIG. 3(C) is a cross-sectional view.

[0060] FIG. 4 shows a lower panel of a cultivation box, wherein FIG. 4(A) is a bottom view, FIG. 4(B) is a perspective view, and FIG. 4(C) is a cross-sectional view.

[0061] FIG. 5 shows a perspective view of a gutter.

[0062] FIG. 6 shows a pot for a cultivation plant, wherein FIG. 6(A) is a perspective view, FIG. 6(B) is a front view, and FIG. 6(C) is a plan view.

[0063] FIG. 7(A) shows a schematic view of a nozzle hung in a cultivation box, and FIG. 7(B) shows an enlarged cross-sectional view of FIG. 7(A).

[0064] FIG. 8(A) is a drawing showing a connection part between a nozzle and a joint pipe of a nutrient solution supply pipe, FIG. 8(B) shows a side view of the joint pipe, and FIG. 8(C) is a bottom view of FIG. 8(B).

[0065] FIG. 9(A) shows a cross-sectional view of a nozzle integrated with a strainer, and FIG. 9(B) shows a cross-sectional view of a main part of the nozzle.

[0066] FIG. 10 is a drawing showing equipment of a cultivation facility.

[0067] FIGS. 11(A) and 11(B) show side views of a second embodiment of a cultivation box in which a lower panel is changed.

[0068] FIGS. 12(A), 12(B), and 12(C) show schematic views of a third embodiment of a cultivation box in which widths and depths of an upper panel and a lower panel are changed.

[0069] FIG. 13 shows a cross-sectional view of a fourth embodiment of a cultivation panel including an intermediate panel.

[0070] FIG. 14 shows a side view of a fifth embodiment in which cultivation boxes are installed in upper and lower multiple stages.

[0071] FIG. 15 shows a pin jet nozzle according to a sixth embodiment, wherein FIG. 15(A) shows a cross-sectional view of a pin jet nozzle with a strainer, FIG. 15(B) shows a side view of the strainer, FIG. 15(C) shows a partial cross-sectional view of the strainer, and FIG. 15(D) shows an explanatory view of a state where a straight rod flow ejected from an ejection hole of a nozzle body impinging on an impingement pin.

[0072] FIG. 16 shows a cross-sectional view of another pin jet nozzle according to a seventh embodiment.

[0073] FIGS. 17(A) and 17(B) are drawings showing a conventional example.

[0074] FIGS. 18(A) to 18(C) are drawings showing another conventional example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0075] Hereinafter, embodiments of a plant cultivation apparatus of the present invention are described with reference to the drawings.

[0076] A first embodiment is shown in FIGS. 1 to 10.

[0077] A plant cultivation apparatus is configured such that many rows of cultivation boxes 1 shown in FIG. 1(B) are arranged through worker passages inside a cultivation facility 50 composed of a vinyl house or a glass-covered greenhouse that takes in sunlight, as shown in FIG. 1(A). In this embodiment, the cultivation boxes 1 are arranged in eight rows in one house of the cultivation facility. In addition, in this embodiment, a cultivation plant P is a tomato or the like that becomes tall when growing, so that the cultivation boxes 1 are provided in one stage in each row. In the case of leafy vegetables such as lettuce that has a low height, the cultivation boxes 1 are provided in two stages in each row, as shown in FIG. 13. Further, three or more stages may be provided. In addition, the cultivation box may be installed in a plant factory whose inside is a cultivation facility, instead of a greenhouse or the like that takes in sunlight.

[0078] The cultivation box 1 is constructed by detachably combining an upper panel 2 and a lower panel 3 to provide a hollow rhizosphere portion 4 serving as a long closed space for hanging a root Pr of the cultivation plant P, and detachably installing a gutter 5 below the lower panel 3. Openings formed at both ends in the length direction when the upper panel and the lower panel extending in the length direction are assembled are closed by both-end closing panels (not shown), thereby forming the hollow rhizosphere portion 4.

[0079] The upper panel 2, the lower panel 3 and the gutter 5 are made of resin or styrene foam. When made of resin or styrene foam, the weight and cost are reduced. The material is not limited as long as it has a required strength, durability, weather resistance, and light weight. The cultivation box 1 has a size which allows the cultivation plants P to be cultivated at certain intervals, and in the present embodiment, the cultivation box 1 has height H of approximately 30 cm and width W of 50 cm, and the length is adjusted according to the cultivation facility 50 by connecting the plurality of cultivation boxes 1 in the length direction. The height H and the width W may be changed depending on the cultivation plant.

[0080] As shown in FIGS. 2 and 3, the upper panel 2 has a substantially mountain shape, and planting holes 6 are provided on inclined side walls 2a on both sides that are formed spreading downward, and arranged in upper and lower two rows in staggered arrangement. Nozzle-mounting holes 7 for inserting the nozzles 10 are provided on a top surface 2b, which is positioned between the inclined side walls 2a on both sides, at intervals in the length direction, and the upper panel 2 functions as a planting panel and a nozzle mounting panel.

[0081] A mounting portion 2c is provided so as to protrude outward from a lower end of the inclined side wall 2a, and a downward fitting concave portion 2d is provided on a lower surface of the mounting portion 2c. The nozzle-mounting hole 7 provided on the top surface 2b is a rectangular hole having a long side in the length direction, and has such a size that allows a nutrient solution supply pipe 14 to pass smoothly with the pair of front and rear nozzles 10 (10A, 10B) attached to a lower end of the nutrient solution supply pipe 14. One nozzle-mounting hole 7 is provided for each of the plurality of planting holes 6 aligned in the longitudinal direction. In this embodiment, one nozzle-mounting hole 7 is provided for three planting holes 6 (for six upper and lower planting holes 6 arranged in a staggered manner).

[0082] Furthermore, an internal observation hole 2h is provided on the inclined side wall 2a at a position close to the nozzle-mounting hole 7, and a cover 2k for opening and closing the internal observation hole 2h is provided.

[0083] As shown in FIGS. 2 and 4, a waste liquid port 8 is provided on a bottom wall 3b which is substantially symmetrical with the upper panel 2 and is opposed to the top surface 2b of the upper panel 2 at intervals in the length direction. A receiving plate portion 3c, on which the mounting portion 2c is put, is provided so as to protrude outward from an each upper end of inclined side walls 3a sandwiching the bottom wall 3b, a fitting convex portion 3d which fits the fitting concave portion 2d of the upper panel 2 is provided on an upper surface of the receiving plate portion 3c, and a pipe-receiving concave portion 3e is provided on a lower surface of the receiving plate portion 3c. Further, a fitting protrusion 3f for attaching the gutter 5 on the entire outer surface of the bottom wall 3b is provided.

[0084] Further, as shown in FIG. 1(B), a CO.sub.2 introduction port 3h is provided on the inclined side wall 3a of the lower panel 3, and CO.sub.2 can be introduced into the hollow rhizosphere portion 4 from a CO.sub.2 tank 80 installed outside the cultivation box 2. The supply time and amount of CO.sub.2 from the CO.sub.2 tank 80 are automatically controlled depending on the detection values of a CO.sub.2 sensor 72 installed in the rhizosphere portion 4 and a solar radiation sensor 71 installed in the greenhouse, and further a growth stage of the plant.

[0085] As shown in FIG. 5, the gutter 5 has a trough shape composed of a bottom wall 5a and both side walls 5b, a fitting concave portion 5f for fitting the fitting protrusion 3f is provided at an each upper end of both side walls 5b, and an outlet port 5h connected to an upper end of a drain pipe 12 is provided at one end of the gutter.

[0086] As shown in FIG. 2(C), the bottom wall 5a of the gutter 5 may be formed to be a slope in which a waste liquid flows down from one end to the other end in the length direction, that is, may be an inclined bottom wall. Alternatively, the cultivation box 1 itself composed of three members may be inclined.

[0087] The mounting portion 2c of the upper panel 2 is put on the receiving plate portion 3c of the lower panel 3 and the fitting convex portion 3d is fitted into the fitting concave portion 2d to assemble a horizontally long box with the hollow rhizosphere portion 4 having a hexagonal cross section, and the gutter 5 is assembled to the lower panel 3, whereby the cultivation box 1 is constructed by three members. The cultivation box 1 is held by a stand composed of commercially available agricultural pipes and receiving fittings. Specifically, as shown in FIG. 1(B), a lengthwise pipe 11A which fits into the pipe-receiving concave portion 3e of the receiving plate portion 3c of the lower panel 3 is supported by brackets 11C attached to left and right support pipes 11B. The left and right support pipes 11B are installed by being stuck into the ground G and connected to a lower connection pipe 11D and an upper connection pipe 11E which supports a lower surface of the gutter 5.

[0088] The root Pr of the cultivation plant P is hung in the hollow rhizosphere portion 4 of the cultivation box 1 from the planting hole 6 of the upper panel 2 by using pot 16 shown in FIGS. 6(A) to 6(C).

[0089] The pot 16 is made of a resin molded product, and has a cylindrical shape with an upper opening to be inserted into the planting hole 6, wherein the upper end thereof is inclined and its inclined periphery has an engaging piece 16a protruding therefrom for engaging, so as to be capable of being inserted into and engaged with the planting hole 6 provided on the inclined side wall 2a. In addition, a large number of openings 16h are provided on the outer peripheral wall and the bottom wall so that the root Pr of the cultivation plant P can extend into the rhizosphere portion 4 through the opening 16h.

[0090] A one-fluid nozzle that sprays only nutrient solution is used as the nozzle 10 to be inserted and mounted in the nozzle-mounting hole 7 of the upper panel 2. As shown in FIGS. 7 and 8, a main nutrient solution supply pipe 13 is inserted and attached to a through hole 14h of an upper end pipe 14u of a nutrient solution supply pipe 14.

[0091] Specifically, as shown in FIGS. 7(A) and 7(B), the nutrient solution supply pipe 14 includes a vertical pipe 14a extending downward from a longitudinal center of the upper end pipe 14u extending in the horizontal direction, and cut portions of the main nutrient solution supply pipe 13 are internally fitted and connected to both ends of the through hole 14h of the upper end pipe 14u.

[0092] A cover 70 sized to close the rectangular nozzle-mounting hole 7 is fixed to an upper periphery of the vertical pipe 14a. A vertically extending through hole 14c inside the vertical pipe 14a is connected to the through hole 14h of the upper end pipe 14u, thereby forming a shape such that the nutrient solution flowing from the main nutrient solution supply pipe 13 into the through hole 14h of the upper end pipe 14u of the nutrient solution supply pipe 14 flows down in the through hole 14c of the vertical pipe 14a to the lower end thereof.

[0093] A joint pipe 60, an inverted T-shaped pipe, is connected to the lower end of the vertical pipe 14a, and a forward-facing nozzle 10A and a rearward-facing nozzle 10B are connected to the respective ends of branch pipes 60a and 60b, which extend in the front-rear length direction at a lower part of the joint pipe 60, by one-touch operation of inserting and rotating.

[0094] As shown in FIGS. 8(A), 8(B) and 8(C), on peripheral walls of the branch pipes 60a and 60b, insertion holes 60k are provided at 90 intervals, and the insertion holes 60k have locking portions 60i at one end in the rotation direction and have such a shape that when the locking pieces 29 provided on the nozzles 10 (10A, 10B) at 90 intervals described below are inserted into the insertion holes 60k and rotated, the locking pieces 29 can be locked and connected to the locking portions 60i.

[0095] The inverted T-shaped through hole 60h of the joint pipe 60 is connected to the lower end of the through hole 14c of the vertical pipe 14a of the nutrient solution supply pipe 14, and the nutrient solution flowing through the through hole 14c is branched and flows into the pair of front and rear nozzles 10A and 10B.

[0096] The vertical pipe 14a of the nutrient solution supply pipe 14 in which the pair of front and rear nozzles 10 (10A, 10B) are attached to the lower end thereof via the joint pipe 60 can be smoothly passed through the nozzle-mounting hole 7 on the top surface 2b of the upper panel 2; and when the cover 70 is brought into contact with the top surface 2b, the nozzle-mounting hole 7 is closed and the pair of front and rear nozzles 10 (10A, 10B) are in the state of being hung in the hollow rhizosphere portion 4.

[0097] The nozzle-mounting holes 7 are provided at intervals in the length direction, the nutrient solution supply pipes 14 are arranged at intervals in the length direction in the rhizosphere portion 4 of the cultivation box, and by spraying the nutrient solution forward from the forward-facing nozzle 10A and rearward from the rearward-facing nozzle 10B, that are provided at the lower end of each nutrient solution supply pipe 14, the entire rhizosphere portion 4 is almost uniformly filled with mist of the nutrient solution to create a high humidity environment.

[0098] Each of the forward-facing nozzle 10A and the rearward-facing nozzle 10B has a structure such that a strainer 17 is integrally mounted on the upstream side, and the nutrient solution flowing into the strainer 17 from the main nutrient solution supply pipe 13 via the nutrient solution supply pipe 14 and the branch pipe of the joint pipe 60 is subjected to removal of foreign matter by the strainer, then flows into the nozzle 10 and is sprayed. The configuration of the strainer 17 is described below.

[0099] The strainer may be installed in a middle of the nutrient solution supply pipe or between the nutrient solution supply pipe and the joint pipe.

[0100] The nozzle 10 (10A, 10B) is a one-fluid nozzle, and sprays only nutrient solution obtained by diluting fertilizer with water at a predetermined ratio. That is, a two-fluid nozzle that requires an air compressor as in a conventional example shown in FIG. 16 is not used.

[0101] The nozzle 10 of a one-fluid nozzle is a hollow conical spray nozzle which sprays the nutrient solution as a swirling flow from a tip of an ejection hole of the nozzle. The average particle size of the spray from the nozzle 10 is set to 10 m to 30 m in the present embodiment.

[0102] As shown in FIG. 9, the nozzle 10 is composed of two members, a nozzle body 23 and a closer 30, both of which are made of a resin molded product. The nozzle body 23 comprises an ejection-side wall 23a and an outer peripheral wall 23b continuous with an outer periphery of the ejection-side wall, and the other end facing the ejection-side wall 23a is opened. The closer 30 is fixedly accommodated in a space 23c surrounded by the ejection-side wall 23a and an inner surface of the outer peripheral wall 23b of the nozzle body 23, and an ejection hole 25 is provided so as to penetrate at a center of the ejection-side wall 23a. The ejection hole 25 has a small-diameter portion connected to an ejection port 25a on the ejection side, a tapered hole 25t of which inflow end side is enlarged is connected to the small-diameter portion, and the tapered hole is connected to a large-diameter straight passage 25u.

[0103] As shown in FIG. 9(B), in the nozzle body 23, an inner surface of the ejection-side wall 23a on the inlet side, that faces the space 23c, is provided with a circular-shaped step part surrounding a large-diameter inflow port 25e which is opened at the center, and a pair of arc-shaped swirling grooves 26 are formed at 180 intervals on the step part. The inner peripheral ends of the swirling grooves 26 are opened and connected to the large-diameter inflow port 25e at 180 intervals.

[0104] The swirling groove 26 is curved in an arc shape, gradually narrowed toward the inner peripheral end, and has an orifice 27 having a minimum width on the inner peripheral end. The width of the opening of the orifice 27 is the same as the width of the ejection port 25a, a minimum diameter portion of the ejection hole 25. As a result, foreign matter smaller than the ejection port is not caught by the orifice 27 of the swirling groove 26 and is discharged outside together with the sprayed nutrient solution from the ejection port 25a. Further, the swirling groove 26 has a U-shaped cross section and its bottom is formed in a round shape, and no edge to which foreign matter is caught is present, so that foreign matter can be easily removed at a time of maintenance.

[0105] The closer 30 has a substantially cylindrical shape and has a liquid inlet port 30c at a center of the leading end on the inlet side. The closer 30 is fixedly accommodated in the space 23c of the nozzle body 23, an ejection-side end face 30a having a flat surface of the closer 30 is pushed and contacted to the step part 23d of the nozzle body 23 and an outer peripheral surface of the closer 30 is pushed and contacted to an inner surface of the outer peripheral wall 23b of the nozzle body 23.

[0106] As the ejection-side end face 30a of the closer 30 is pushed and contacted to the step part 23d surrounding the large-diameter inflow port 25e of the nozzle body 23, the swirling grooves 26, 26 are formed as swirling passages having a closed cross section.

[0107] Four arc-shaped depressions are formed on the outer peripheral surface 30g of the closer 30 at 90 intervals, thereby forming liquid passages 33 between the outer peripheral wall 23b of the nozzle body. The liquid passage 33 is connected to a liquid inlet portion of the nozzle body 23.

[0108] A radial liquid passage connected to a depression of the liquid inlet port 30c is provided on the outer peripheral wall surrounding the liquid inlet port 30c of the closer 30. Thereby, liquid flowing into the liquid inlet port 30c of the closer 30 flows into the liquid inlet portion of the nozzle body 23 through the liquid passage 33, flows into the ejection hole 25 through the swirling groove 26 as a swirling flow, and is sprayed outside from the ejection port 25a at the tip.

[0109] The nozzle 10 assembled by fixing the closer 30 inside the nozzle body 23 is attached by one-touch operation of inserting the inlet side of the nozzle body 23 into the end of each of the branch pipes 60a and 60b of the joint pipe 60 connected to the lower end of the nutrient solution supply pipe 14 and then rotating, as described above.

[0110] The strainer 17, which is integrally fixedly accommodated in the inlet side of the nozzle body 23, is made of a resin material having three-dimensionally continuous pores and having a porosity of 40% to 80%. In the nozzle 10, the sizes of the ejection port 25a and the orifice 27 of the swirling groove 26 are larger than an average diameter of the pores of the strainer 17 so that foreign matter that may cause the clog of the orifice 27 or the ejection port 25a of the nozzle can be caught by the strainer 17 in advance.

[0111] The nutrient solution Q supplied from the main nutrient solution supply pipe 13 is introduced into the strainer 17 integrated with the nozzle 10 through the nutrient solution supply pipe 14 and the branch pipes 60a and 60b of the joint pipe 60, and foreign matter mixed in the nutrient solution Q is caught by the strainer 17. The nutrient solution that has passed through the strainer 17 flows into the closer 30 in the nozzle 10 and further flows into the swirling groove 26 through the liquid passage 33.

[0112] In the process of flowing through the swirling groove 26, a cross-sectional area of the flow passage is gradually reduced toward the orifice 27 so that the liquid pressure is increased, and the fluid flows into the ejection hole 25 while swirling and is sprayed from the ejection port 25a of the nozzle body 23 while swirling, thereby scattered outside. Since the injection pressure is increased at the orifice 27 of the swirling groove 26 and the minimum diameter portion of the ejection hole 25, flight distance of the spray ejected to the outside is increased. In addition, since the fluid passes through the ejection hole 25 while swirling in the state of being swirled in the swirling groove 26, the droplets collide with each other and are atomized. In this manner, due to its excellent atomization function, semi-dry fog having an average particle diameter of 10 m to 100 m, preferably 10 m to 50 m or less, more preferably 10 m to 30 m can be sprayed, even when the spray pressure is as low as 0.5 MPa to 2 MPa.

[0113] In the case where foreign matter is mixed in the nutrient solution Q supplied from the main nutrient solution supply pipe 13, first, foreign matter to be caught by the orifice 27 and the ejection hole 25 is previously caught by the pores of strainer 17 at the time of passing through the strainer 17. Therefore, foreign matter to be caught by the orifice 27 and the minimum diameter portion of the ejection hole 25 does not flow into the nozzle 10. Further, foreign matter which is smaller than the minimum diameter portion of the ejection hole 25 and passes through the strainer 17 is discharged from the ejection hole 25 to the outside without being caught by the orifice 27 of the swirling groove 26. As a result, the function of preventing clogging due to foreign matter in the ejection hole 25 and the orifice 27 is also excellent.

[0114] In the cultivation facility 50 provided with the cultivation box 1 of the present invention, the plurality of main nutrient solution supply pipes 13 (four in this embodiment) to be piped to the top surface 2b of the upper panel 2 of each cultivation box 1 are collectively connected to a supply pipe 40, and the supply pipe 40 is collectively connected to a fertilizer tank 42 that stores the nutrient solution to be sprayed through a supply main pipe 41, as shown in FIG. 10. A water level sensor 58, a stirrer 59, and an EC/PH sensor 69 are installed in the fertilizer tank 42. An electric open/close valve 44 controlled by a control panel 43 is provided on each of the supply pipe 40, and a pump 45 controlled by the control panel 43 is provided on the main supply pipe 41. The fertilizer tank 42 is connected to a water supply pipe 52 and is further connected to a concentrated liquid fertilizer tank 46 and an acid-alkali tank 47 via a pipe, thereby providing a liquid fertilizer mixing unit 65. Furthermore, the fertilizer tank 42 is connected to a circulation type chiller device 48 via a circulation pipe 49 to prevent the liquid fertilizer stored in the fertilizer tank 42 from overheating.

[0115] Further, the drain pipe 12 connected to the gutter 5 is connected to a return tank 55 via a drain pipe 54, and a waste liquid collected in the return tank 55 is connected to a purification device 56 via a circulation pipe 57 and is returned to the return tank 55 by a pump 67. In the purification device 56, the waste liquid is sterilized by using UV, ozone, a photocatalyst or the like to be regenerated as a nutrient solution. In addition, in order to reuse the purified waste liquid stored in the return tank 55, a pump 66 is installed in the tank, the pumped waste liquid is transported through a pipe 61 and is filtered through an automatic cleaning filter 62, and then returned to the fertilizer tank 42. In this way, the waste liquid that has been purified by filtration is supplied to the fertilizer tank 42, whereby the nutrient solution is reused without waste.

[0116] The control panel 43 is electrically connected to the electric open/close valve 44, the water level sensor 58, the stirrer 59 and the EC/PH sensor 69 that are installed in the fertilizer tank 42, and further connected to an electromagnetic open/close valve, a pressure sensor and a flow rate sensor that are installed on various pipes and the pump 66 in the return tank 55, and outputs drive signals as well as receives detection values from the various sensors.

[0117] In addition, in the greenhouse of the cultivation facility 50, a solar radiation sensor 71 is provided as shown in FIG. 1(A), and a controller 70 that receives detection values of the solar radiation sensor 71 and a CO.sub.2 sensor 72 installed in the rhizosphere portion in the cultivation box 1 is installed. The controller 70 also receives detection values of the various sensors from the control panel 43. According to the EC value and the PH value detected by the EC/PH sensor 69 installed in the fertilizer tank 42, the amount of solar radiation detected by the solar radiation sensor 71 and the growth stage of the cultivation plant, the controller 70 transmits a command for controlling the supply amounts of the concentrated liquid, and acid and alkali components to be supplied to the fertilizer tank 42 from the concentrated liquid fertilizer tank 46 and the acid-alkali tank 47 of the liquid fertilizer mixing unit 65. In addition, when a power outage and an abnormality of the electric parts, an abnormality of a water level in the tank, a disconnection of the CO.sub.2 sensor 72 installed in the rhizosphere portion, or a disconnection of the solar radiation sensor 71 is detected, the controller 70 transmits an alarm notifying the abnormality to the portable communication device 75.

[0118] Furthermore, a generator that operates in a power failure, or a battery that is supplied with power from a solar power generation panel for charging, is equipped.

[0119] Further, the controller 70 automatically controls a CO.sub.2 concentration in the rhizosphere portion in the cultivation box 1 and a spraying cycle of the nutrient solution from the fertilizer tank 42 depending on the plant growth stage and the detection value of the solar radiation sensor 71. The growth stage of the plant is divided into, for example, an initial stage, a middle stage and a final stage.

[0120] In the plant cultivation apparatus of the present invention, the nutrient solution is sprayed toward the rhizosphere portion 4 of the cultivation plant P in the respective cultivation boxes 1 from the nozzles 10 (10A, 10B) via the nutrient solution supply pipe 14 and the joint pipe 60 provided with the branch pipe, thereby creating humidified nutrient solution environment. The spray is conducted so as to have an average particle diameter of 10 m to 50 m (10 m to 30 m in the present embodiment), so that it can be prevented from agglomerating and dropping as water droplets, is floated in air in the cultivation box 1, and an absorption efficiency of the nutrient solution can be increased, since roots Pr of the cultivation plant P can easily adsorb the nutrient solution. In addition, the amount of the nutrient solution sprayed from the nozzle is set so that the humidity in the rhizosphere portion of the cultivation box 1 is high.

[0121] Further, since the plurality of pairs of front and rear nozzles 10 (10A and 10B) are arranged at intervals in the cultivation box 1, there is no need to extend the spraying distance from each nozzle 10, and therefore, a one-fluid nozzle which sprays only the nutrient solution without mixing with a compressed air can be used as the nozzle 10. In addition, there is no need to install a fan for circulating the spray in the cultivation box 1, and so an air compressor and a fan can be eliminated, thereby reducing running costs and equipment costs.

[0122] In particular, in the present cultivation box 1, the nozzle 10 is hung from the top surface 2b, that is the upper end of the upper panel 2, in the hollow rhizosphere portion 4, the planting holes 6 are provided on the inclined side walls 2a, 2a on both sides in upper and lower two rows, and the root Pr of the cultivation plant P is placed in the pot 16 and hung in the hollow rhizosphere portion 4. Therefore, while the cultivation box 1 is downsized, the cultivation plants P can be planted at a high density, and the number of nozzles 10 for spraying the nutrient solution to the rhizosphere portion of these cultivation plants can be reduced.

[0123] Further, droplets of the surplus nutrient solution (namely, the waste liquid) that fall downward in the hollow rhizosphere portion 4 fall to the bottom of the lower panel 3, and droplets attached to the side wall can also fall to the bottom. And, since the waste liquid port 8 is provided on the bottom wall 3b of the lower panel 3 and is formed to allow the waste liquid to flow down to the lower gutter 5, the waste liquid does not accumulate at the bottom of the lower panel 3 and the root Pr of the grown cultivation plant is prevented from soaking in the waste liquid and becoming root rot. Further, since the gutter 5 is connected to the drain pipe 12, the waste liquid can be automatically stored in the return tank 55. The waste liquid stored in the return tank 55 is transported to the purification device 56 for purification, and can be returned to the fertilizer tank 42 after being filtered through the automatic cleaning filter and reused.

[0124] The nozzle 10 can be easily attached to the upper panel 2 simply by piping the main nutrient solution supply pipe 13 on the top surface 2b, placing the nozzle 10 in the nozzle-mounting hole 7 and inserting it, and the nozzle-mounting hole 7 can be closed by the cover 70 fixed to the nutrient solution supply pipe 14 to which the nozzle 10 is attached. Conversely, at the time of maintenance of the nozzle 10, the nozzle 10 can be taken out simply by pulling the nutrient solution supply pipe 14 upward. Thus, there is an advantage that the attachment and maintenance of the nozzle 10 are facilitated.

[0125] In addition, since the internal observation hole 2h is provided in the vicinity of the nozzle mounting portion, the inside of the hollow rhizosphere portion 4 can be easily observed by removing the cover 2k.

[0126] Further, since CO.sub.2 is supplied into the cultivation box 1 from the CO.sub.2 tank 80, the growth of the cultivation plant can be promoted. In addition, the control panel 43 and the controller 70 are installed, so that the EC and PH of fertilizer to be applied can be automatically adjusted appropriately depending on the growth stage of the cultivation plant. Further, the operator can be notified of the abnormality of the electric system, so that the work efficiency can be improved as well as the work load can be reduced.

[0127] Furthermore, the cultivation box 1 can be easily assembled from the upper panel 2, the lower panel 3 and the gutter 5 inside the cultivation facility 50. These upper panel 2 and the lower panel 3 can be transported to the cultivation facility in a stacked manner, so that the transportability is excellent and the initial cost can be reduced.

[0128] The nutrient solution to be sprayed is prevented from overheating in the fertilizer tank 42 by using the chiller device 48, so that it is possible to prevent the temperature inside the cultivation box 1 from rising by spraying and the root Pr from being killed.

[0129] FIGS. 11(A) and 11(B) show a second embodiment in which the form of the cultivation box is changed.

[0130] As shown in the drawing, the inclined side walls 3a on both sides of the lower panel 3 may be configured so as to have a stepped shape including an upper portion 3al having a steep inclination angle and a lower portion 3a2 having a gentler inclination angle on the bottom side. With the shapes of the modified examples (A) and (B), the volume of the lower part of the hollow rhizosphere portion 4 surrounded by the upper panel 2 and the lower panel 3 can be increased, and even when the roots Pr of the cultivation plant P grow, entanglement between the roots can be suppressed and the flight distance of the spray from the nozzle 10 can be secured.

[0131] FIGS. 12(A), 12(B) and 12(C) show a third embodiment in which the form of the cultivation box is changed.

[0132] In the cultivation box 1 of the third embodiment, the side walls 2a-3 on both sides of the upper panel 2 and the side walls 3a-3 on both sides of the lower panel 3 are vertical, and the top surface 2b-3 of the upper panel 2 and the bottom wall 3b-3 of the lower panel 3 are horizontal.

[0133] The third embodiment A of FIG. 12(A) is wide and shallow, and the volume of the hollow rhizosphere portion 4 is expanded in the width direction. The nozzle-mounting hole is provided at a center in the width direction of the top surface 2b-3 of the upper panel 2, and the nozzle 10 is inserted and hung in the rhizosphere portion 4. Planting holes are provided (not shown) at positions sandwiching the nozzle-mounting holes into which the nozzles 10 are inserted, and pots for filling the roots of the cultivation plants are put in these planting holes as in the first embodiment.

[0134] This third embodiment A is suitably applied in the case where the roots of the cultivation plant are spread horizontally.

[0135] The third embodiment B of FIG. 12(B) is narrow and deep, the volume of the hollow rhizosphere portion 4 is increased in the depth direction, and is suitably applied in the case where the cultivation plant has a vertically long root.

[0136] The third embodiment C of FIG. 12(C) has the same width and shallow depth as the third embodiment A, and the volume of the hollow rhizosphere portion 4 is expanded in the width direction. In the third embodiment C, two nozzle-mounting holes are provided at intervals in the width direction of the top surface 2b-3 of the upper panel 2, and the nozzles 10 are inserted and hung in the rhizosphere portion 4, respectively. Planting holes are provided (not shown) at positions sandwiching the nozzle-mounting holes into which the nozzles 10 are inserted, and pots for filling the roots of the cultivation plants are put in these planting holes as in the first embodiment. In the cultivation box of the third embodiment C, cultivation plants can be cultivated in two rows in the width direction. In addition, it is also possible to extend the width of the cultivation box further, hang the nozzles in three or four rows, and cultivate the cultivation plants by arranging in three or four rows so as to face each other.

[0137] FIG. 13 shows a fourth embodiment in which the form of the cultivation box is changed.

[0138] In the above first to third embodiments, the hollow rhizosphere portion 4 is formed by the upper panel 2 and the lower panel 3; however in the fourth embodiment, an intermediate panel 85 of a rectangular flat plate is interposed between the inclined side walls 2a, 3a of the upper panel 2 and the lower panel 3 on both sides, whereby the volume of the rhizosphere portion 4 is increased. Specifically, an upper end surface 85a of the intermediate panel 85 is brought into contact with the mounting portion 2c protruding outward from the lower end of the inclined side wall 2a of the upper panel 2, and a fitting convex portion 8d which fits the fitting concave portion 2d provided on the lower surface of the mounting portion 2c is provided so as to protrude from a center of the upper end surface 85a.

[0139] Similarly, a lower end surface 85b of the intermediate panel 85 is brought into contact with the receiving plate portion 3c protruding outward from the upper end of the inclined side wall 3a of the lower panel 3, and a fitting concave portion 8e which fits the fitting convex portion 3d provided on the upper surface of the receiving plate portion 3c is provided so as to protrude from a center of the lower end surface 85b.

[0140] As to the upper panel 2 and the lower panel 3, the same panels can be used as in the case where they are directly connected to each other without the intermediate panel 85 interposed therebetween, and only by using the intermediate panel 85 having the same shape on the left and right side, it becomes possible to increase the volume of the rhizosphere portion 4 and cope with the case where the growth of the root of the cultivated plant is large.

[0141] As described above, by installing the intermediate panel 85 and changing the height of the intermediate panel without changing the upper panel and the lower panel, the volume of the rhizosphere portion can be changed depending on the amount of root growth of the cultivated plant, thereby enabling coping with the cultivated plant.

[0142] FIG. 14 shows a fifth embodiment in which the arrangement of the cultivation boxes 1 in the house of the cultivation facility is changed. In the first embodiment, the cultivation box 1 is composed of a single stage, meanwhile in the fifth embodiment, the cultivation boxes 1 are attached to the support pipe 11B in two upper and lower stages.

[0143] In the first embodiment, since a tall tomato or the like is cultivated as the cultivation plant P, the cultivation box 1 is composed of a single stage; however in the case of a short plant such as lettuce or a strawberry, an upper cultivation box 1-U may be provided above a lower cultivation box 1-D with a certain height space as shown in the fifth embodiment. With this configuration, productivity can be increased.

[0144] Further, instead of planting the roots of the cultivation plant in the pot, a support sheet is attached to the inner surface of the inclined side wall of the upper panel, a slit for inserting the root is formed at a position for closing the planting hole, and the root may be inserted in the slit to be supported. In addition, the arrangement of the planting holes is not limited to the upper and lower two rows in a staggered arrangement, and may be one row or three or more rows. Further, the shape of the upper panel is not limited to a mountain shape, and the upper panel may have a horizontal upper surface wherein the nozzle-mounting holes may be provided at a center of the upper surface and the planting holes may be provided on both sides of them. Further, the upper surface may be formed in a one-sided triangle shape and installed along an outer wall of the cultivation facility.

[0145] FIG. 15 shows a sixth embodiment in which a pin jet nozzle of a one-fluid nozzle is employed as the spray nozzle.

[0146] A pin jet nozzle 10-P provided with a strainer, that is installed at each of the front and rear ends of the joint pipe 60 at the lower end of the nutrient solution supply pipe 14 hung in the rhizosphere portion 4 of the cultivation box 1, is used in stead of the hollow conical nozzle 10 that sprays a swirling flow of the first embodiment. The pin jet nozzle 10-P is configured such that: an ejection hole composed of a straight hole for ejecting a straight rod flow is provided at a center of an ejection-side closing wall of a nozzle body; and an impingement pin, which the straight rod flow impinges on, is provided so as to project from an outer surface of the ejection-side closing wall of the nozzle body at a position facing the ejection hole, whereby the straight rod flow ejected from the ejection hole is made to impinge on the impingement pin to atomize the spray.

[0147] Specifically, the pin jet nozzle 10-P is provide with a strainer 17 composed of a porous material made of resin as in the first embodiment.

[0148] The nozzle 10-P is provided with a J-shaped impingement frame 93 protruding from an outer surface of an ejection-side wall 92a formed of a closed wall at one end of a cylindrical nozzle body 92 formed by metal injection. The impingement frame 93 includes a vertical frame portion 93a protruding from the outer surface of the distal end of the ejection-side wall 92a and a horizontal frame portion 93b protruding from the distal end of the vertical frame portion 93a across the center axis, and a pin hole 93c is formed at the center axis of the horizontal frame portion 93b on the distal side thereof. A ceramic impingement pin 94 is inserted into the pin hole 93c so as to project toward the ejection-side wall 92a of the nozzle body, and the back side of that is fixed to the pin hole 93c with an adhesive 98. The projecting part of the impingement pin 94 has a conical shape that becomes thinner toward the tip, and has a small-diameter impingement surface 94a.

[0149] An ejection hole 95 formed of a straight hole is provided on the center axis of the ejection-side wall 92a at one end of the nozzle body 92, and a straight passage 96 having a circular cross-section and a constant inner diameter surrounded by a flat inner surface of the ejection-side wall 92a and an outer peripheral wall is provided. The ejection hole 95 is connected to the straight passage 96, and the nutrient solution is ejected from the straight passage 96 through the ejection hole 95 as a straight rod flow. The diameter of the impingement surface 94a of the impingement pin 94 is set in the range of 100% to 115% of the diameter of the counter ejection hole 95.

[0150] In the nozzle 10-P, spray pressure is set in the range of 0.5 MPa to 2.0 MPa, a spray flow rate is set in the range of 1 L/hr to 5 L/hr, and an average particle diameter of the sprayed nutrient solution is in the range of 10 m to 100 m, preferably 10 m to 50 m, more preferably 10 m to 30 m.

[0151] As with the nozzle of the first embodiment, the nozzle body 92 is provided with locking pieces 99 projecting from the outer peripheral wall at 90 intervals so as to be capable of connecting to the branch pipe of the joint pipe by one-touch operation, and as shown in FIG. 8, the connection to the insertion hole 60k provided on the branch pipe at 90 intervals can be made by simply rotating.

[0152] The rear end of the nozzle body 92 is an opening, and a front portion 17a of the strainer 17 is accommodated therein. The strainer 17 is made of a resin material having three-dimensionally continuous pores 17c as shown in FIG. 15(C), and has a porosity of 40% to 80%. The strainer 17 has the front portion 17a and a rear portion 17b continuous with each other, and has a liquid passage 17h composed of a center hole extending from a front end of the front portion 17a to a middle part of the rear portion. The liquid passage 17h is opened to the straight passage 96, and is configured so as to flow from the straight passage 96 to the ejection hole 95. Further, as shown in FIG. 14(B), an outer peripheral surface of the rear portion of the strainer 17 is formed such that four arc portions 17c protrude to form a petal shape, thereby increasing a surface area thereof and increasing a liquid absorption amount of the strainer 17.

[0153] The nozzle 10-P provided with the strainer 17 of the above-described embodiment is attached to each of the front and rear ends of the joint pipe, which is provided at the lower end of the nutrient solution supply pipe hung in the rhizosphere portion 4 of the cultivation box 1, so as to spray the nutrient solution toward the root of the cultivation plant in the front and rear direction. It flows into the ejection hole 95 through the straight passage 96 of the nozzle body 92 via the strainer 17, is ejected from the narrow ejection hole 95 as a straight rod flow Qs as shown in FIG. 15(D), and impinges on the impingement surface 94a at the tip of the impingement pin 94 at the opposing position. At that time, since the diameter of the ejection hole 95 is minim, pressure of the nutrient solution passing through the ejection hole 95 is increased, and the straight rod flow Qs is ejected in the state where the ejection pressure is increased to impinge on the impingement surface, whereby all the droplet is atomized and scattered outside. By impinging the high-pressure straight rod flow on the impingement pin in this way, it is possible to spray with an average particle diameter of 10 m to 50 m or less.

[0154] In addition, since there is no swirling groove, that is present in the hollow conical nozzle that sprays a swirling flow, and it has a straight ejection hole, it is excellent in that it is hard to clog. Further, since the impingement pin is made of ceramic, it is possible to prevent abrasion due to the impingement of the high-pressure straight rod flow.

[0155] FIG. 16 shows a seventh embodiment, in which a pin jet one-fluid nozzle 10-PP of another embodiment is employed.

[0156] The pin jet one-fluid nozzle 10-PP is formed by insert-molding an ejection-side tip member 86, of which an ejection hole 86h of a straight hole and an impingement pin 86p are integrally formed of ceramic, into a nozzle body 87 made of a fluororesin.

[0157] As shown in the drawing, in the ejection-side tip member 86, a U-shaped impingement frame 86b is provided so as to protrude from both sides of an ejection-side wall 86a mounted to an ejection-side opening of the nozzle body 87, and an impingement pin 86p is provided so as to project on a center axis of a horizontal frame portion 86b2 which connects distal ends of vertical frame portions 86b1 on both sides of the impingement frame 86b. An ejection hole 86h is provided at a center of the ejection-side wall 86a, and the ejection hole 86h and the impingement pin 86p are set in the same relationship as the nozzle 10-P of the fifth embodiment.

[0158] The nozzle body 87 of which the ejection-side opening is closed by the tip member 86 is provided with a straight flow path 87b surrounded by a cylindrical outer peripheral wall 87a and the ejection-side wall 86a, and the straight flow path 87b is connected to the ejection hole 86h. Locking pieces 87k projecting from an outer surface of the outer peripheral wall 87a of the nozzle body 87 are provided at 90 intervals so as to be capable of connecting to the branch pipe of the joint pipe by one-touch operation, similarly to the nozzle shown in FIG. 14, and can be connected to the insertion holes of the branch pipe, that is provided at 90 intervals, by simply rotating. The strainer 17 is attached to the nozzle body 87 in the same manner as in the above embodiment.

[0159] The nozzle of the seventh embodiment is used in the same manner as the nozzle of the sixth embodiment, and a straight rod flow is ejected from the narrow ejection hole 86h and impinges on the impingement surface at the tip of the impingement pin 86p at the opposing position, whereby all the droplet is atomized and scattered outside. By impinging the high-pressure straight rod flow on the impingement pin in this way, it is possible to spray with an average particle diameter of 10 m to 50 m or less.

[0160] The present invention is not limited to the above-described embodiments, and can be variously modified in the range without departing from the gist of the present invention.

REFERENCE SIGNS LIST

[0161] 1 cultivation box [0162] 2 upper panel [0163] 2a inclined side wall [0164] 2b top surface [0165] 3 lower panel [0166] 3a inclined side wall [0167] 3b bottom wall [0168] 4 hollow rhizosphere portion [0169] 5 gutter [0170] 6 planting hole [0171] 7 nozzle-mounting hole [0172] 8 waste liquid port [0173] 10 (10A, 10B, 10-P, 10-PP) nozzle [0174] 13 main nutrient solution supply pipe [0175] 14 nutrient solution supply pipe [0176] 16 pot [0177] 80 CO.sub.2 tank [0178] 85 intermediate panel [0179] P cultivation plant [0180] Pr root