AU2014202160B2

AU2014202160B2 - Plant growth apparatus of multistage rack type and plant growth system

Info

Publication number: AU2014202160B2
Application number: AU2014202160A
Authority: AU
Inventors: Junya Fuse; Norihiro Higashi
Original assignee: Mitsubishi Chemical Aqua Solutions Co Ltd
Current assignee: Mitsubishi Chemical Aqua Solutions Co Ltd
Priority date: 2013-05-31
Filing date: 2014-02-14
Publication date: 2017-07-13
Anticipated expiration: 2034-02-14
Also published as: WO2014192331A1; CN203788814U; JP6123495B2; AU2014202160A1; CN110012750B; JP2014233231A; CN104206213B; CN104206213A; CN110012750A

Abstract

- 27 [Object] To provide a plant growth apparatus of multistage rack type, which can efficiently dissipate heat from an artificial lighting unit to the atmosphere, and which can prevent a rise of temperature of a nutrient solution flowing on a tray disposed just above the artificial lighting unit and a rise of temperature of rhizospheric portions of plants put on the tray, and a plant growth system including the plant growth apparatus of multistage rack type. [Solution] In plant growth apparatuses 3 to 6 of multistage rack type including artificial lighting units 13 disposed at lower surfaces of racks, each artificial lighting unit 13 includes a box 13a disposed on the lower surface side of the rack, a fluorescent lamp 13c, and a power supply unit 13g. The power supply unit 13g is disposed on a bottom plate 13e of the box 13a, and the power supply unit 13g and a top plate 13d are spaced from each other. The bottom plate 13e serves also as a reflecting plate for the fluorescent lamp 13c. [Selected Figure] Fig. 7

Description

» - 1 - PLANT GROWTH APPARATUS OF MULTISTAGE RACK TYPE AND PLANT GROWTH SYSTEM Field of Invention [0001]

The present invention relates to a plant growth apparatus of multistage rack type, such as a seedling growth apparatus including an artificial lighting unit, and more particularly to a plant growth apparatus of multistage rack type in which the artificial lighting unit has an improved structure. The present invention further relates to a plant growth system including the plant growth apparatus of multistage rack type.

Background of Invention [0002]

Patent Literatures 1 to 3 each disclose a plant growth apparatus of multistage rack type in which racks are provided in multiple stages with a tray disposed on an upper surface of each of the racks, seedlings are placed on the tray under unit, such irrigation, and light from an artificial as a fluorescent lamp, is applied to the lighting seedlings for growth. The artificial lighting unit is disposed on the lower surface side of each rack, and it emits the light towards plants on a rack that is positioned in a stage lower than the relevant rack by one. Plants on the rack in the uppermost stage are illuminated with light “ 2 -from the artificial lighting unit disposed at a ceiling surface of the plant growth apparatus of multistage rack type.

[0003] 'The artificial lighting unit generates heat. To prevent the temperature of growing environment for the plants from rising beyond a setting range with the generated heat,

Patent Literature 1 discloses such an arrangement that the heat from the artificial lighting unit is transmitted to a nutrient solution flowing on the tray positioned just above the artificial lighting unit, and that a cooling unit for cooling the nutrient solution is provided in a circulation path of the nutrient solution. However, the disclosed arrangement requires the cooling unit and increases the equipment cost. In the case of growing the plants by a method of supplying the nutrient solution intermittently, the heat transmitted from the artificial lighting unit raises the temperature of rhizospheric portions of plants through the tray during a period in which supply of the nutrient solution is stopped. Thus, the disclosed method tends to cause adverse effects on growth of the plants.

[0004]

To prevent the heat generated by the artificial lighting unit from being transmitted to the tray positioned just above the artificial lighting unit, it is also - 3 - 2014202160 01 Jun2017 conceivable to arrange the tray and the artificial lighting unit in spaced relation. In that case, however, a vertical spacing between adjacent racks is increased, and the number of plants grown per unit space is reduced.

List of Literature Patent Literature [0005]

Patent Literature 1: Japanese Patent Publication 2009-34064A

Patent Literature 2: Japanese Patent Publication 2003-52253A

Patent Literature 3: W02004/026023 Summary of Invention [0006]

An embodiment of the present invention seeks to provide a plant growth apparatus of multistage rack type, which can efficiently dissipate heat from an artificial lighting unit to the atmosphere, and which can prevent a rise of the temperature of a nutrient solution flowing on a tray positioned just above the artificial lighting unit and a rise of the temperature of rhizospheric portions of plants on the tray, and to further provide a plant growth system including the plant growth apparatus of multistage rack type.

[0007]

The present invention provides a plant growth apparatus 9126983_1 (GHMatters) P96849.AU - 4 - 2014202160 01 Jun2017 of multistage rack type including plant growth racks arranged in multiple stages in a vertical direction, an irrigation device that supplies a nutrient solution flowing on each rack, and an artificial lighting unit disposed at a lower surface of each rack to illuminate plants on the rack in a lower stage with light, wherein the artificial lighting unit includes a box disposed on the lower surface side of the rack, a light emitter disposed on the lower surface side of the box, and a power supply unit disposed in the box to operate the light emitter, the box includes a top plate and a bottom plate, and the power supply unit is disposed on the bottom plate, the power supply unit and the top plate being spaced from each other,_wherein the irrigation device includes irrigation trays each constituting the rack, and wherein air flow forming means is disposed to form an air flow flowing from a front side to rear side of a space on an upper side of each rack.

[0008]

In the above-described plant growth apparatus of multistage rack type, air flow forming means is preferably disposed to form an air flow in a space on an upper side of each rack.

9126983_1 (GHMatters) P96849.AU - 4a - 2014202160 01 Jun2017 [0009]

In the present invention, the box is preferably-contacted with the lower surface of the rack. Furthermore, the bottom plate of the box preferably serves as a reflecting plate to reflect light from the light emitter.

[0010]

In the plant growth system according to the present 9126983J (GHMatters) P96849.AU invention, the above-described plant growth apparatus of multistage rack type is installed inside a closed building. Advantageous Effects of Invention [0011]

According to the present invention, the following advantageous effects are obtained. (1) In the plant growth apparatus of multistage rack type according to the present invention, the artificial lighting unit disposed at the lower surface of the rack includes the box, the light emitter disposed on the lower surface side of the box, and the power supply unit disposed in the box, the power supply unit is disposed on the bottom plate of the box? and the power supply unit is spaced from the top plate of the box. Therefore, heat generated from the power supply unit of the artificial lighting unit is mainly transmitted downwards from the bottom plate of the box, and an amount of heat transmitted to the rack on the upper side of the artificial lighting unit is small. As a result, the nutrient solution flowing on the rack (tray) and rhizospheric portions of plants put on the tray are prevented from being warmed by the heat of the artificial lighting unit, and the plants are efficiently grown.

[0012] A cooling unit for cooling the nutrient solution is no longer required, and the equipment cost can be reduced. The term "nutrient solution" used here implies, e.g., water containing fertilizer components or pure water.

[0013]

Since the plants can be grown by a method of intermittently stopping the nutrient solution that is supplied to the tray, an amount of water applied to the plants can be restricted by setting a time during which the nutrient solution is supplied to the tray per day to a shorter time. Therefore, seedlings having good quality, i.e., being highly resistant against drying even after being transplanted to fields or greenhouses, can be cultivated.

[0014]

In the general case of seedling growth, a time during which rhizospheric portions of plants are immersed in the nutrient solution is preferably set to a shorter time from the viewpoint of preventing "excessive water supply” to seedlings. Accordingly, it is preferable to properly adjust the time during which the nutrient solution is supplied to the tray depending on the type of seedlings to be grown, and to keep rhizospheric portions of the seedlings in a state as dry as possible.

[0015] (2.} Since an air flow is streamed through a space on the upper side of the rack, air warmed by the heat of the artificial lighting unit can be drained from that space, and the temperature in that space can be kept more constant.

[0016] (3) Even with the arrangement that the artificial lighting unit is contacted with the lower surface of the rack, an amount of the heat transmitted from the artificial lighting unit to the rack is small. When the artificial lighting unit is contacted with the lower surface of the rack, the height of the plant growth apparatus of multiple stage type can be lowered without reducing the height of the space on the upper side of the rack. Alternatively, the number of rack stages can be increased without increasing the height of the plant, growth apparatus of multiple stage type.

[0017] (4) Since the bottom plate of the box serves as the reflecting plate to reflect light from the light emitter, the light from the light emitter can be efficiently utilized for growth of the plants.

Brief Description of Drawings [0018]

Fig. 1 is a plan view of a plant growth system including a plant growth apparatus of multistage rack type according to an embodiment.

Fig. 2 is a sectional view taken along a line II-II in Fig. 1.

Fig. 3 is a front view of the plant growth apparatus of 8 multistage rack type according to the embodiment.

Fig. 4 is a sectional view taken along a line IV-IV in Fig, 3.

Fig. 5 is a plan view of a tray used in the plant growth apparatus of multistage rack type according to the embodiment.

Fig. Fig. 6 is a perspective view of the tray of Fig- 5. 7 is a sectional view taken along a line VII-VII in Fig. 5,

Fig. 8 is a bottom view of an artificial lighting unit. Fig. 9 is a sectional view taken along a line IX-IX in Fig. 8.

Fig. 10 is a sectional view of a tray used in a plant growth apparatus of multistage rack type according to another embodiment.

Description of Embodiments [0019]

Preferred embodiments of the present invention will be described below with reference to Figs. 1 to 10. As illustrated in Figs. 1 and 2, a plural number (four in an illustrated example) of box-shaped plant growth apparatuses 3, 4, 5 and 6 of multistage rack type are installed inside a room of a closed building 1, which is surrounded by heat-resistant wall surfaces and which is completely shielded against light. In this embodiment, the plant growth 9 apparatus is a seedling growth apparatus.

[0020]

In Fig. 1, two plant growth apparatuses 3 and 4 of multistage rack type are arrayed in a row such that their open front surfaces are directed in the same direction, and other two plant growth apparatuses 5 and 6 of multistage rack type are also arrayed in a row such that their open front surfaces are directed in the same direction. Two rows of the plant growth apparatuses are arranged inside the room in a state where the open front surfaces of the plant growth apparatuses in the two lines face each other. Furthermore, a work space in such a size as allowing one or plural workers to carry out operations is formed between the two rows. A space having a width of about 50 to 500 mm is formed between the wall surface of the room and a rear surface of each of the plant growth apparatuses 3 to 6 of multistage rack type, thereby defining a path for air that has passed through the plant growth apparatuses 3 to 6 of multistage rack type.

[0021]

Preferably, an air curtain is installed inside a door 2 through which the workers come in and out of the room, so that outdoor air does not enter the room when the workers come in and out of the room.

[0022] 10

In upper portions of the wall surfaces of the room, air cond.itloners 7 to 10 are installed each of which has the function of adjusting the temperature and the humidity of air in the room and of circulating the air that has been adjusted in temperature and humidity to setting conditions.

[0023]

As illustrated in Figs. 3 and 4, each of the plant growth apparatuses 3 to 6 of multistage rack, type is a boxshaped structure, which is opened at its front surface and which includes a pedestal 3c, right and left lateral panels 3a, a rear panel 3b on the rear side, and a top panel 3e defining a ceiling portion. Inside the box-shaped structure, a plurality of seedling growth racks 12 is arranged in multiple stages at certain intervals in the vertical direction.

[0024]

Each of the plant growth apparatuses 3 to 6 of multistage rack type has a height of about 2000 mm, i.e., such a height as allowing the workers to carry out the operations on all the stages. Preferably, a width of the seedling growth rack 12 is set to such a value, e..g., about 1000 mm to 2000 mm, that a plurality of resin-made cell trays, each containing several tens to several hundreds cells {small pots) arrayed in a grid pattern, can be placed side by side, and that, the temperature and the humidity in an upper space above each rack 12 can be adjusted to be kept constant. Furthermore, preferably, a depth of the seedling growth rack 12 is set to 500 mm to 1000 mm. A plurality of cell trays 40 (see Fig, 1) are substantially horizontally placed on each seedling growth rack 12. In general, dimensions of one cell tray are about 300 mm in width and about 600 mm in length.

[0025]

The seedling growth rack 12 in the lowermost stage is placed on the pedestal 3c. Levelness of the seedling growth rack 12 can be adjusted by an adjuster (not illustrated) that is provided on the pedestal 3c.

[0026]

An irrigation device 30, described later, is provided in each seedling growth rack 12.

[0027]

Artificial lighting units 13 are disposed at respective lower surfaces of the seedling growth racks 12 in the second or higher stages and of the top panel 3e such that light from each artificial lighting unit 13 is applied to plants growing in the cell trays 40 on the seedling growth rack 12 positioned just under the relevant artificial lighting unit 13. In this embodiment, the artificial lighting unit 13 except for one in the uppermost stage is mounted to a lower surface of an irrigation tray 31 (described later). 12 [0028] A light emitter of the artificial lighting unit 13 is preferably a fluorescent lamp or a LSD, for example. In this embodiment, a straight fluorescent lamp is used as a light source.

[0029]

Figs. 8 and 9 illustrate details of structure of the artificial lighting unit 13. Fig. 8 is a bottom view of the artificial lighting unit 13, and Fig. 9 is a sectional, view taken along a line IX-IX in Fig. 8. In the artificial lighting unit 13, plural pairs (six in this embodiment) of sockets 13b are mounted to a lower surface of a box 13a, and both ends of a fluorescent lamp 13c are fitted to each pair of sockets 13b and 13b. A switch 13s is further attached to the lower surface of the box 13a.

[0030] A box 13a is a box-like body having a top plate 13d and a bottom plate 13e, The bottom plate 13e servo® arso as a reflecting plate that reflects light, from the fluorescent lamp 13c. A power supply unit 13g incorporating eiectnc circuit components 13f, such as a stabilizer, an inv®rter, a constant current circuit, a constant voltage a current limiting resistance, etc., is disposed in ^ox between 13a. In this embodiment, three power supply units 13g are arranged between the fluorescent lamps 13c, i.e*f 13 the fluorescent lamps 13c in first and second lines, between the fluorescent lamps 13c in third and fourth lines, and between the fluorescent lamps 13c in fifth and sixth lines. The power supply units 13g are each mounted to the bottom plate 13e of the box 13a. A gap of about 3 to 30 mm is left between each power supply unit 13g and the top plate 13d of the box 13a. In the artificial lighting unit 13 of this embodiment, heat generated from the power supply unit 13g is transmitted to the bottom plate 13e and then dissipated from the bottom plate 13e. In other words, the generated heat is transmitted to air flowing through a seedling growth space under the artificial lighting unit 13. Heat generated from each fluorescent lamp 13c is also transmitted to that flow of air.

[0031]

Because the gap is present between the power supply unit 13g and the box top plate 13d, an amount of heat transmitted from the power supply unit 13g to the top plate 13d. is very small. Therefore, the nutrient solution flowing on the irrigation tray 31 and the rhizospheric portions of the plants put in the cell tray 40 are prevented from being heated by the heat from the artificial lighting units 13.

[0032]

As illustrated in Fig. 4, ventilation openings are formed in the rear panel 3b behind respective spaces 14 - (seedling growth spaces) between adjacent two of the seedling growth racks 12 and between the seedling growth rack 12 in the uppermost stage and the top panel 3e, and air fans 15 are mounted respectively to the ventilation openings. By operating the air fans 15, circulation flows of air are generated in the room as denoted by arrows in Fig. 2. More specifically, the air having the temperature and the humidity adjusted by the air conditioners 7 to 10 is sucked into the seedling growth space in each stage of the seedling growth racks 12 from the open front surface side of the plant growth apparatuses 3 to 6 of multistage rack type, and is discharged to the side behind each rear panel 3b through the ventilation openings. The discharged air rises between the rear side of the rear panel 3b and the wall surface of the building, and is then sucked into the air conditioners 7 to 10. After being adjusted in temperature and humidity, the air is blown out again toward the open front surface side of the plant growth apparatuses 3 to 6 of multistage rack type.

[0033]

When the two rows of the plant growth apparatuses 3 and 4 of multistage rack type and the plant growth apparatuses 5 and 6 of multistage rack type are arrayed in lay out to form, the work space between the two rows as illustrated in Figs. 1 and 2, the work space functions also as a circulation path 15 for the air, whereby effective circulation flows are produced.

[0034]

When the circula growth spaces in the multistage rack type. tion flows pass through the seedling plant growth apparatuses 3 to 6 of water vapor evaporated from the irrigation devices, culture media, the plants, etc. and the heat released from the artificial lighting units 13 are entrained with the circulation flows. By circulating the circulation flows at the temperature and the humidity adjusted by the air conditioners 7 to 10 at all times, the inside of the room can be kept as environment at the temperature and the humidity optimum for growth of the plants. A flow speed of the air flowing through the seedling growth spaces is preferably 0.1 m/sec or higher, more preferably 0.2 m/sec or higher, and even more preferably 0.3 m/sec or higher. If the speed of the air flow is too fast, there 'would be a risk that a problem occurs in growth of the plants. Therefore, the flow speed of the air is preferably 2.0 m/sec or lower.

[0035]

While, in this embodiment, the air flow is streamed from the front surface of the seedling growth space to the rear surface side of the rack through the fans 15 in a state under negative pressure, the air flow may be streamed conversely from the rear surface side to the front surface side of the rack in a state under positive pressure.

However, a more uniform air flow is obtained in the seedling growth space by causing the air flow to stream from the front surface side to the rear surface side of the rack in a state under negative pressure.

[0036]

In this embodiment, a rack plate of each seedling growth rack 12 is constituted by the irrigation tray 31 of the irrigation device, (bottom-side irrigation device) 30, and irrigation is effectuated from a bottom surface of the cell tray 40 that is placed on the irrigation tray 31. An example of a structure of the irrigation device 30 will be described below with reference to Figs. 5 to 7. Fig. 5 is a plan view of the irrigation device, Fig. 6 is a perspective view thereof, and Fig. 7 is a sectional view taken along a line VII-VII in Fig. 5.

[0037]

The irrigation device 30 includes the rectangular irrigation tray 31 having sidewalls 31a, 31b and 31c that are erected respectively at a rear side and left and right lateral sides of a bottom plate 31d. A drain pit 32 in continuity with the bottom plate 31d of the irrigation tray 31 is termed along a front side of the irrigation tray 31 where there is no sidewall, and aide drain opening 32a is formed at one end of the drain pit 32. The drain pit 32 and the bottom plate 3Id are partitioned by a dam 34, and the nutrient solution flows out into the drain pit 32 from cutouts 34a that are formed at both ends of the dam 34. Furthermore, a feed pipe 33 for supplying the nutrient solution into the irrigation tray 31 is disposed to extend along the sidewall 31a erected at the rear side of the irrigation tray 31. The nutrient solution is supplied onto the tray 31 through a plurality of small holes 33a formed in the feed pipe 33.

[0038] A plurality of ribs 35, each having a height of about 7 Mi, is disposed on an upper surface of the bottom plate 31d of the irrigation device to extend toward the drain pit 32 parallel to each other. The cell tray 40 is placed on the ribs 35.

[0039]

The irrigation device 30 is dimensioned, as illustrated in Fig. 4, such that when the irrigation trays 31 are placed on the seedling growth racks 12 of the plant growth apparatuses 3 to 6 of multistage rack type, the drain pits 32 are positioned to project from the open front surfaces of the plant growth apparatuses 3 to 6. With the drain pits 32 projecting from the open front surfaces of the plant growth apparatuses, it is easier to collect the nutrient solution 18 drained through the drain openings 32a of the drain pits 32 of the irrigation trays 31 placed in the seedling growth rack 12 of each stage, and to drain the nutrient solution to the outside of the building 1.

[0040]

When the nutrient solution is continuously supplied through the snail holes 33a formed in the feed pipe 33 of the irrigation device 30, the nutrient solution is stemmed by the dam 34 and is pooled up to a predetermined level. While the nutrient solution is supplied from the feed pipe 33, the nutrient solution flows out to the drain pit 32 through the cutouts 34a a little by a little, h pooled state of the nutrient solution is preferably maintained in the irrigation tray 30 at a level of, e.g,, about 10 to 12 nun by adjusting an amount of the supplied nutrient solution and an amount of the nutrient solution drained through the cutouts "34a. The water is sucked up by the capillary action to the culture medium in each cell 41 through cell holes 42, which are formed in the bottom surface of each cell 41 in the cell tray 40 placed on the ribs 35, such that the culture media in all the cells 41 are brought into a water saturated state in a short time.

[0041]

The artificial lighting unit 13 is mounted to a lower surface of the bottom plate 31d of the irrigation tray 31. - 19 -

While, in this embodiment., the top plate 13d of the box 13a of the artificial lighting unit 13 is directly contacted with the lower surface of the irrigation tray 31, a spacer or a heat insulating material may be interposed therebetween [0042]

In the irrigation device 30 of this embodiment, as illustrated in Fig. 7, an upper surface of the bottom plate 31d of the irrigation tray 31 is inclined toward the drain pit 32. Therefore, when the irrigation is stopped, the nutrient solution can be drained to the drain pit 32 in a short time. In the case of inclining the upper surface of the bottom plate 31d, the cell tray 40 placed on the ribs 35 can be horizontally held by gradually changing the height of each rib 35 such that a top 35a of the rib lies horizontally [0043]

Fig. 10 illustrates another example of the irrigation device used in the present invention. The same members as those in Figs. 5 to 7 are denoted by the same reference signs. In an irrigation device 30' illustrated in Fig. 10, when the cell tray 40 is placed on the bottom plate 3Id of the irrigation tray 31, an under tray 50 is interposed between the bottom plate 31d of the irrigation tray 31 and the cell tray 40. The under tray 50 has rigidity at such a level as being able to support the cell tray 40 including the cells 41 in each of which the culture medium is put. A plurality of small holes 51 is formed in a bottom surface of the under tray 50, and a plurality of projections 52 is formed on the rear side of the under tray 50. The projections 52 function as gap holding means for holding a gap between the bottom plate 31d of the irrigation tray 31 and the bottom surface of the cell tray 40 when the cell tray 40 is accommodated in the irrigation tray 31 together with the under tray 50.

[0044]

Also in the irrigation device 30’ of Fig. 10, when the nutrient solution is supplied from the feed pipe 33 of the irrigation device 30* and is pooled up to a predetermined level, the nutrient solution is introduced into the under tray 50 through the small holes 51 of the under tray 50.

The water is then sucked up by the capillary action to the culture medium in each ceil 41 through the cell holes 42, which are formed in the bottom surface of each cell 41 in the cell tray 40.

[0045]

Furthermore, in Fig. 10, the artificial lighting unit 13 is similarly mounted to the lower surface of the bottom plate 31d of the irrigation tray 31.

[0046]

As in the above-described embodiment, the cell tray 40 placed on the irrigation tray 31 is constituted as a unitary - 21 tray shape including several tens to several hundreds cells 41 arrayed in a grid pattern, and dimensions of one cell tray are about 300 ran in width and about 600 mm in length. However, the present invention is not limited to the above-described arrangement.

[0047]

To artificially supply carbon dioxide consumed by seedlings for photosynthesis, as illustrated in Fig. 1, a liquefied carbon dioxide bomb 16 is installed outside the building 1. The carbon dioxide is supplied from the carbon dioxide bomb 16 such that a concentration of the carbon dioxide in the room, measured using a carbon dioxide concentration meter, is held constant.

[0048]

By employing the above-described seedling growth apparatus to grow seedlings, it is possible to automatically adjust environment conditions, such as a quantity of light, temperature, humidity, carbon dioxide, and water, which are suitable for the growth of the seedlings. Since all the seedlings on the seedling growth racks can be grown under the same environment., uniformity in quality of the grown seedlings can be increased.

[0049]

In the above-described plant growth apparatus of multistage rack type, the heat generated from the artificial 22 - lighting unit 13 is transmitted to the box bottom plate 13e, which serves also as the reflecting plate, and is further transmitted from the bottom plate 13e to the air flowing through the seedling growth space. An amount of the heat transmitted from the artificial lighting unit 13 to the irrigation tray 31 on the upper side is very small. Accordingly, the temperature of the nutrient, solution residing on the irrigation tray 31 can be controlled to be kept, within a predetermined range.

[0050]

The above-described embodiments axe representative examples of the present invention, and the present invention is not limited to the above-described embodiments. For instance, the size of the room and the number of installed plant growth apparatuses of multistage rack type may be other than those mentioned above. The air conditioners may be installed at the ceiling, [0051]

While the present invention has been described in detail above in connection with the particular embodiments, it is apparent to those skilled in the art that the present invention can be variously modified without departing from the gist and the scope of the present invention.

This application claims the benefit of Japanese Patent Application No. 2013-115787 filed May 31, 2013, which is hereby incorporated by reference herein in its entirety.

[0052] 1 closed building 3f 4? 5, 6 plant growth apparatuses of multistage rack type 3a lateral panel 3b rear panel 3c pedestal 3e top panel 7 to 10 air conditioners 12 seedling growth rack 13 artificial lighting unit 13a box 13b socket 13c fluorescent lamp 13d top plate 13e bottom plate 13f electric circuit components 13g power supply unit 13s switch 15 air fan 16 carbon dioxide bomb 30f 30' irrigation devices 31 irrigation tray 3Id bottom plate 2014202160 01 Jun2017 - 24 - 32 32a 33 33a 34 34a 35 40 41 42 50 51 52 drain pit drain opening feed pipe small hole dam cutout rib cell tray cell cell hole under tray small hole projection [0053] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

9126983_1 (GHMatters) P96849.AU

Claims

CLAIMS 1 A plant growth apparatus of multistage rack type including plant growth racks arranged in multiple stages in a vertical direction, an irrigation device that supplies a nutrient solution flowing on each rack, and an artificial lighting unit disposed at a lower surface of each rack to illuminate plants on the rack in a lower stage with light, wherein the artificial lighting unit includes a box disposed on the lower surface side of the rack, a light emitter disposed on the lower surface side of the box, and a power supply unit disposed in the box to operate the light emitter, and the box includes a top plate and a bottom plate, and the power supply unit is disposed on the bottom plate, the power supply unit and the top plate being spaced from each other,_ wherein the irrigation device includes irrigation trays each constituting the rack, and wherein air flow forming means is disposed to form an air flow flowing from a front side to rear side of a space on an upper side of each rack.
2 The plant growth apparatus of multistage rack type according to Claim 1, wherein the box is directly contacted with the lower surface of the rack.
3 The plant growth apparatus of multistage rack type according to Claim 1, wherein the box is mounted to the lower surface of the rack via a spacer or a heat insulating material interposed therebetween.
4 The plant growth apparatus of multistage rack type according to any one of Claims 1 to 3, wherein the irrigation tray has a bottom plate, and sidewalls being erected respectively at a rear side and left and right lateral sides of the bottom plate, wherein a drain pit is formed along a front side of the bottom plate, the drain pit protruding downwardly from the bottom plate, and wherein the artificial lighting unit is mounted to a lower surface of the bottom plate.
5 The plant growth apparatus of multistage rack type according to any one of Claims 1 to 4, wherein the bottom plate of the box serves as a reflecting plate to reflect light from the light emitter.
6 The plant growth apparatus of multistage rack type according to any one of Claims 1 to 5, wherein the space of the upper side of each rack is surrounded by right and left lateral panels and a rear panel, and a front of the space is open, and wherein the air flow forming means includes a ventilation opening formed in the rear panel, and an air fan mounted to the ventilation opening.
7 A plant growth system wherein the plant growth apparatus of multistage rack type according to any one of Claims 1 to 6 is installed inside a closed building.