JP3247652U - Bottom irrigation device for seedlings - Google Patents

Abstract

[Problem] To provide a bottom irrigation device for raising seedlings equipped with a suitable drainage device to replace a siphon pipe with an M-shaped cross section. [Solution] A bottom irrigation device for raising seedlings 100 comprises a water tank 2 that stores water for bottom irrigation of a seedling container 1, a drainage tank 10 that communicates with the water tank and stores water at the same level as the water tank, and a drainage device 11 that is installed in the drainage tank and drains the water in the drainage tank. The drainage device includes a bell siphon 15 that automatically starts draining when the water level in the drainage tank rises to a predetermined drainage start level L2. [Selected Figure] Figure 1

Description

This disclosure relates to a bottom irrigation device for seedlings.

A bottom irrigation device for seedlings is known that irrigates seeds or seedlings planted in soil in a seedling container from the bottom. The applicant previously proposed such a bottom irrigation device equipped with a siphon pipe with an M-shaped cross section (see Patent Document 1). This siphon pipe can automatically start draining water when the water level rises to a specified drainage start level.

JP 2003-61492 A

However, the above-mentioned M-shaped cross-section siphon pipe is made of ceramic and is generally used in water supply systems for public toilets, etc., and has become difficult to obtain in recent years. Therefore, a suitable drainage device to replace this M-shaped cross-section siphon pipe is desired.

Therefore, this disclosure was conceived in consideration of the above circumstances, and its purpose is to provide a bottom irrigation device for seedlings equipped with a suitable drainage device that can replace the M-shaped cross-section siphon pipe.

According to one aspect of the present disclosure,
A water tank for storing water for bottom irrigation of seedling containers;
a drainage tank that is connected to the water tank and stores water at the same level as the water tank;
A drainage device installed in the drainage tank for draining water from the drainage tank;
Equipped with
The drainage device includes a bell siphon that automatically starts draining when the water level in the drainage tank rises to a predetermined drainage start level.

According to the present disclosure, it is possible to provide a bottom irrigation device for seedlings equipped with a suitable drainage device that can replace an M-shaped cross-section siphon pipe.

1 is a schematic diagram showing a seedling bottom irrigation device of a first embodiment. FIG. FIG. 2 is a cross-sectional view showing a main part of FIG. 1 . FIG. 11 is a cross-sectional view showing a main part of a second embodiment. FIG. 11 is a cross-sectional view showing a main part of a third embodiment. FIG. 13 is a cross-sectional view showing a main part of a fourth embodiment. FIG. 13 is a cross-sectional view showing a main part of a fifth embodiment. FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. FIG. 13 is a cross-sectional view showing a main part of a sixth embodiment.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Please note that the present disclosure is not limited to the following embodiments.

[First embodiment]
Fig. 1 is a schematic diagram showing a seedling bottom irrigation device according to a first embodiment. Fig. 2 is an enlarged cross-sectional view showing a main part of Fig. 1.

As shown in Figures 1 and 2, the bottom irrigation device 100 comprises a cell tray 1 as a seedling container, and a water tank 2 in which water is stored for bottom irrigation of the cell tray 1. A water-permeable mounting plate 3 is attached at a predetermined height position in the water tank 2, and the cell tray 1 is supported by being placed on this mounting plate 3.

As shown in detail in Figure 2, the cell tray 1 is a shallow, plastic dish-shaped container with multiple cells 4 that are separated from one another. Each of these cells 4 is filled with soil 5, and seeds are planted in it. The seeds eventually germinate and become seedlings 6 as shown in the figure. Each cell 4 has a water supply hole 7 in the bottom.

The water tank 2 is made of stainless steel and has an open top, a bottom plate 8 and side plates 9.

The mounting plate 3 is made of stainless steel punching metal and is removably attached to the water tank 2 by a bracket (not shown). The mounting plate 3 has a plurality of through holes 3A formed therein to allow water to pass through. When the cell tray 1 is placed on the mounting plate 3, the levels of the upper end of the water tank 2 and the upper end of the cell tray 1 in the height direction are made approximately equal. In this embodiment, the upper end level of the water tank 2 is set as the upper limit level L1, which is the upper limit of water supply.

The bottom irrigation device 100 also includes a drainage tank 10 that is connected to the water tank 2 and stores water at the same level as the water tank 2, and a drainage device 11 that is installed in the drainage tank 10 and drains the water in the drainage tank 10.

The drainage tank 10 is also made of stainless steel and is an open-top tank with a bottom plate 12 and a side plate 13. In this embodiment, the drainage tank 10 is directly connected to the water tank 2. In other words, the water tank 2 and the drainage tank 10 are horizontally adjacent to each other, and the side plates 9, 13 at the boundary between them have been removed, so that the water tank 2 and the drainage tank 10 are configured as if they were a single water tank. The top level of the drainage tank 10 is set to the same level as the top level of the water tank 2.

However, the bottom plate 12 of the drainage tank 10 is located at a lower level than the bottom plate 8 of the water storage tank 2. Therefore, a step is created between the bottom plate 8 of the water storage tank 2 and the bottom plate 12 of the drainage tank 10, and a side plate 13 is provided at this step to connect the bottom plates 8 and 12.

Alternatively, the water tank 2 and the drainage tank 10 may be completely separated, and the bottom of the water tank 2 may be connected to the inside of the drainage tank 10 via a pipe or the like.

The bottom irrigation device 100 is equipped with a water supply device for supplying water into the water tank 2. The water supply device is equipped with a water supply pipe 14 which serves as an outlet for water. In the present embodiment, the water supply pipe 14 is provided facing downward into the drainage tank 10. The water supply pipe 14 directly supplies water into the drainage tank 10. Since the water tank 2 and the drainage tank 10 are connected, the water supplied into the drainage tank 10 also reaches the water tank 2, and the water levels in the water tank 2 and the drainage tank 10 are the same.

Alternatively, the water supply pipe 14 may supply water directly into the water tank 2. In this case, the water supplied to the water tank 2 also reaches the drainage tank 10, so that the water levels in the water tank 2 and the drainage tank 10 are the same.

The water supply device of this embodiment is configured to supply tap water. The water supply device also includes an electromagnetic valve and a controller (e.g., a timer switch) for controlling the start and end times of water supply, etc.

As shown in detail in FIG. 2, the drainage device 11 includes a Bell Siphon 15. The Bell Siphon 15 is configured to automatically start draining when the water level in the drainage tank 10 (i.e., the water level in the water tank 2) rises to a predetermined drainage start level L2.

The Bell Siphon 15 is made of PVC pipes and their piping parts. Unless otherwise specified, the PVC pipes are of the most common circular cross section. The Bell Siphon 15 comprises an inner siphon pipe 16 that stands upward from the bottom plate 12 of the drainage tank 10, an outer siphon pipe 17 that is fitted around the inner siphon pipe 16, an elbow pipe 18 that is connected to the inner siphon pipe 16 and is positioned below the bottom plate 12, and a support pipe 19 that is attached to the bottom plate 12 of the drainage tank 10 and supports the inner siphon pipe 16 and elbow pipe 18.

In more detail, a mounting hole 20 is provided in the bottom plate 12 of the drainage tank 10, and the support pipe 19 is inserted into the mounting hole 20 from above and fixed. The support pipe 19 extends in the vertical direction, and a flange 21 is integrally provided at its longitudinal middle portion. A male thread 22 is formed on the outer periphery of the support pipe 19 below the flange 21. The support pipe 19 is inserted into the mounting hole 20 from above, and with the flange 21 abutting against the bottom plate 12 of the drainage tank 10, the nut 23 is tightened onto the male thread 22 from below. As a result, with the flange 21 and the nut 23 sandwiching the bottom plate 12, the flange 21 and the nut 23 are in close contact with the bottom plate 12, and the support pipe 19 is firmly and watertightly fixed to the bottom plate 12.

The upper end of the support tube 19 is provided with an enlarged diameter section 24 for enlarging its inner diameter. The lower end of the inner siphon tube 16 is inserted or pressed into this enlarged diameter section 24 until it abuts against the lower end of the enlarged diameter section 24, and is fixed watertightly with an adhesive.

The inner siphon pipe 16 is a straight pipe that extends vertically, and its upper end position is set to be equal to the drainage start level L2.

The lower end of the support pipe 19 is also provided with an enlarged diameter section 25 for enlarging its inner diameter. The upper end of a connecting pipe 26 that connects the support pipe 19 and the elbow pipe 18 is inserted or pressed into this enlarged diameter section 25 until it abuts against the upper end of the enlarged diameter section 25, and is fixed watertight with an adhesive. The connecting pipe 26 is also a straight pipe that extends vertically.

The elbow pipe 18 has an upward inlet section 27, a horizontal outlet section 28, and a 90° bent pipe section 29 that connects the inlet section 27 and the outlet section 28.

The inlet 27 is provided with an enlarged diameter section 30 to expand its inner diameter. The lower end of the connecting pipe 26 is inserted or pressed into this enlarged diameter section 30 until it abuts against the lower end of the enlarged diameter section 30, and is fixed watertight with an adhesive.

The outlet section 28 is also provided with an enlarged diameter section 31 for enlarging its inner diameter. The inlet end of the elbow outlet pipe 32 is inserted or pressed into this enlarged diameter section 31 until it abuts against the back of the enlarged diameter section 31, and is fixed watertight with an adhesive.

The elbow outlet pipe 32 is an auxiliary pipe attached to extend the outlet portion 28 of the elbow pipe 18, and is a short straight pipe extending horizontally. The elbow outlet pipe 32 may be omitted.

The outer siphon pipe 17 is a straight pipe extending in the vertical direction, and its upper end is closed by a cover plate 33. The outer siphon pipe 17 also stands upward relative to the bottom plate 12 of the drainage tank 10. The outer siphon pipe 17 has a larger diameter than the inner siphon pipe 16, and is arranged coaxially with the inner siphon pipe 16. The outer siphon pipe 17 is spaced apart from the inner siphon pipe 16 in the radial and axial directions. This forms a water passage 34 between the outer siphon pipe 17 and the inner siphon pipe 16.

The outer siphon pipe 17 is placed on the bottom plate 12 while being fitted to the outside of the flange 21. Because the outer siphon pipe 17 is fitted to the flange 21, the outer siphon pipe 17 is accurately positioned relative to the inner siphon pipe 16, and displacement is prevented. Because the outer siphon pipe 17 is simply placed on the bottom plate 12, it can be easily attached and detached, which facilitates maintenance.

At the lower end of the outer siphon pipe 17, a siphon inlet hole 35 is provided for introducing water into the outer siphon pipe 17. The siphon inlet hole 35 is a rectangular hole cut out from the lower end surface of the outer siphon pipe 17 to a predetermined distance above, and multiple siphon inlet holes 35 are provided in the circumferential direction of the outer siphon pipe 17. The upper end position of the siphon inlet hole 35 is set to be equal to a predetermined drainage end level L3. This drainage end level L3 is of course lower than the drainage start level L2, and is also set to a level lower than the cell tray 1 and, in this embodiment, lower than the bottom plate 8 of the water tank 2.

On the other hand, the drainage start level L2 is set to a level at which the soil 5 in the cell tray 1 is fully submerged when the water level rises to this level. The drainage start level L2 is also set to a level lower than the upper limit level L1 mentioned above.

The components of the Bell Siphon 15 described above can be easily and inexpensively manufactured using commercially available PVC pipes and associated piping parts.

As shown in FIG. 1, the bottom irrigation device 100 is provided with an overflow pipe 36 to prevent water from overflowing from the water tank 2 and the drainage tank 10 in the event of an abnormality in the bell siphon 15. The overflow pipe 36 can be configured in the same manner as the assembly of the inner siphon pipe 16, the support pipe 19, and the connecting pipe 26 described above. The upper end of the overflow pipe 36 is positioned at a predetermined overflow start level L4, which is higher than the drainage start level L2 and slightly lower than the upper limit level L1.

In addition, below the drainage tank 10, a drainage container 37 is provided to receive the water discharged from the elbow outlet pipe 32 and the overflow pipe 36. In this embodiment, the discharged water is dropped into the drainage container 37 from a slightly higher position, but alternatively, a separate pipe may be connected to the outlet of the elbow outlet pipe 32 and the overflow pipe 36 to guide the wastewater to the bottom of the drainage container 37. Instead of storing the wastewater in the drainage container 37, the wastewater may be discharged into the sewer.

The bottom watering device 100 of this embodiment is applied, for example, as an artificial cultivation device installed on each shelf of a multi-tiered cultivation shelf. In this case, for example, the artificial cultivation device is installed in an air-conditioned room, and an artificial light source consisting of an LED or the like is installed on each shelf. In the illustrated example, for simplicity, only one cell tray 1 is provided. However, when applied to such an artificial cultivation device, typically multiple cell trays 1 are provided on each shelf. Meanwhile, the drainage container 37 may be common to multiple shelves. The artificial cultivation device can be applied, for example, as a test device for checking the germination rate of seeds.

Next, we will explain the effects of this embodiment.

The bottom irrigation device 100 of this embodiment is used to perform bottom irrigation, for example, once every predetermined time (for example, once every morning once per day). In the initial state, there is no water in the water tank 2, water has accumulated in the drainage tank 10 up to the drainage end level L3, and water supply from the water supply pipe 14 has been stopped.

When the specified irrigation timing arrives, water supply from the water supply pipe 14 begins. At this time, the solenoid valve of the water supply device is turned on and opened, and water that passes through the solenoid valve is supplied from the water supply pipe 14 to the drainage tank 10. The solenoid valve is automatically turned on and off by a controller (e.g., a timer switch).

Water first accumulates in the drainage tank 10, and the water level in the drainage tank 10 rises. Water enters the water passage 34 in the outer siphon pipe 17 from the siphon inlet hole 35 of the outer siphon pipe 17, and the water level also rises in the outer siphon pipe 17. The water levels in the drainage tank 10 and the outer siphon pipe 17 are at the same level.

After that, when the water level reaches the level of the upper surface of the bottom plate 8 of the water tank 2, water will accumulate in the water tank 2, and the water levels in the water tank 2 and the drainage tank 10 will rise to the same level.

Then, before the water level rises to reach the drainage start level L2, the soil 5 in the cell tray 1 is immersed in water. That is, the water passes through the through hole 3A of the mounting plate 3 and the water supply hole 7 of the cell tray 1, is supplied to the soil 5 in the cell tray 1, and is absorbed by the soil 5. This achieves bottom watering.

Then, when the water level rises and reaches the drainage start level L2, drainage begins. After the water level reaches the drainage start level L2, water flows into the inner siphon pipe 16 from the upper end inlet of the inner siphon pipe 16. The water that flows down the inner siphon pipe 16 passes through the support pipe 19, connecting pipe 26, elbow pipe 18, and elbow outlet pipe 32 in that order, and is discharged from the elbow outlet pipe 32.

During this process, as the water passes through the elbow pipe 18, the flow resistance increases, and the elbow pipe 18 becomes largely blocked with water. As a result, the space between the inner siphon pipe 16 and the elbow pipe 18 is largely filled with water, and the well-known siphon action begins.

Immediately after the siphoning action begins, the water supply from the water supply pipe 14 is automatically stopped. That is, the solenoid valve of the water supply device is turned off by the controller, the solenoid valve is closed, and the water supply from the water supply pipe 14 is stopped. In this way, the controller is configured to automatically stop the water supply immediately after the siphoning action begins.

After the siphoning action begins, the water in the drainage tank 10, and therefore the water in the water tank 2, is drained relatively quickly. The water levels in the drainage tank 10 and the water tank 2 gradually drop, and when the water in the water tank 2 runs out, only the water level in the drainage tank 10 drops.

When the water level eventually reaches the drainage end level L3, drainage automatically stops. That is, immediately after the water level reaches the drainage end level L3, air is sucked into the outer siphon pipe 17 through the siphon inlet hole 35 of the outer siphon pipe 17. This interrupts the continuity of the water and ends the siphon action. In this way, drainage automatically stops and the water level is maintained at approximately the drainage end level L3.

This completes one cycle of the water supply and drainage process. When the next irrigation timing arrives, the above water supply and drainage process is repeated, and this water supply and drainage process is repeatedly executed at each irrigation timing.

As described above, according to this embodiment, since the drainage device 11 includes the Bell Siphon 15, it is possible to provide a bottom irrigation device 100 for raising seedlings that is equipped with a suitable drainage device 11 that replaces the conventional siphon pipe with an M-shaped cross section. In particular, since the Bell Siphon 15 can be made from commercially available PVC pipes and their piping parts, it can be made easily and inexpensively, and there is no need to use siphon pipes with an M-shaped cross section even in recent years when they have been difficult to obtain.

In addition, because the Bell Siphon 15 does not include a solenoid valve, it is possible to avoid the inconvenience of soil and other substances contained in the wastewater causing the solenoid valve to malfunction and preventing the water from being discharged, as is the case with conventional siphon pipes with an M-shaped cross section. In other words, the Bell Siphon 15 makes it possible to provide an automatic drainage device that is highly reliable and has little risk of malfunction.

On the other hand, in the unlikely event that an abnormality occurs in the bell siphon 15 or the water supply device, there is a risk that the water level in the drainage tank 10 and the water tank 2 will rise far above the drainage start level L2. In this case, when the water level reaches the overflow start level L4, the water in the drainage tank 10 will then be drained through the overflow pipe 36. This makes it possible to prevent water from overflowing from the water tank 2 and the drainage tank 10.

[Second embodiment]
Next, a second embodiment of the present disclosure will be described. Note that a description of the same parts as in the first embodiment will be omitted, and the following description will focus mainly on the differences from the first embodiment.

Figure 3 is a cross-sectional view showing a drainage device 11 of the second embodiment. This drainage device 11 includes an inverted J-shaped siphon 40.

The inverted J-shaped siphon 40 is also made of PVC pipes and their piping parts. The inverted J-shaped siphon 40 includes a first siphon pipe 41 that is substantially similar to the inner siphon pipe 16 described above, and a support pipe 19, a connecting pipe 26, an elbow pipe 18, and an elbow outlet pipe 32 that are similar to those described above. The inverted J-shaped siphon 40 also includes a first elbow pipe 42, a second siphon pipe 43, a second elbow pipe 44, and a third siphon pipe 45 that are connected in sequence to the upstream side of the first siphon pipe 41. The section from the connecting pipe 26 to the third siphon pipe 45 forms an inverted J-shaped pipeline.

The first siphon pipe 41 is a straight pipe extending in the vertical direction, its length is slightly shorter than the inner siphon pipe 16, and it is connected to the support pipe 19 in the same manner as described above.

The first elbow pipe 42 is configured similarly to the elbow pipe 18, and its downstream end is connected to the upper end or upstream end of the first siphon pipe 41. The method of connecting the first to third siphon pipes 41, 43, 45 to the first and second elbow pipes 42, 44 is the same as the method of connecting the connecting pipe 26 and elbow pipe 18 described above. The first elbow pipe 42 is bent 90° from downward to sideways as it moves from the downstream end to the upstream end.

The second siphon pipe 43 is a straight pipe extending horizontally, its length is shorter than that of the first siphon pipe 41, and it is connected to the upstream end of the first elbow pipe 42.

The second elbow pipe 44 is connected at its downstream end to the upstream end of the second siphon pipe 43. The second elbow pipe 44 is bent 90° from sideways to downward as it moves from the downstream end to the upstream end.

The third siphon pipe 45 is a straight pipe extending in the vertical direction, and its length is shorter than that of the first siphon pipe 41. The third siphon pipe 45 is connected at its downstream end to the upstream end of the second elbow pipe 44.

The lower end or upstream end of the third siphon pipe 45 defines the inlet 46 of the inverted J-shaped siphon 40 and is spaced upward from the bottom plate 12 of the drainage tank 10. The inlet 46 of the inverted J-shaped siphon 40 is directed toward the bottom plate 12 while being spaced upward from the bottom plate 12 of the drainage tank 10.

In this inverted J-shaped siphon 40, the lower end position of the highest part of the internal flow path, specifically the lower end position of the flow path in the second siphon pipe 43, is set to be equal to the drainage start level L2. Also, the lower end position of the third siphon pipe 45 is set to be equal to the drainage end level L3.

The effects of this embodiment are almost the same as those of the first embodiment. When the water level in the drainage tank 10 rises and reaches the drainage start level L2, drainage begins and water flows into the first siphon pipe 41. Then, the siphon action begins and the water in the drainage tank 10 and the water storage tank 2 is drained relatively quickly. Immediately after drainage begins, the water supply from the water supply pipe 14 is automatically stopped. The water levels in the drainage tank 10 and the water storage tank 2 gradually drop.

When the water level eventually reaches the drainage end level L3, air is immediately sucked into the third siphon pipe 45 from the inlet 46, the siphon action is terminated, and drainage is automatically stopped.

In this embodiment, the drainage device 11 includes an inverted J-shaped siphon 40, so that it is possible to provide a bottom irrigation device 100 for raising seedlings that is equipped with a suitable drainage device 11 that replaces the conventional siphon pipe with an M-shaped cross section. In particular, the inverted J-shaped siphon 40 can be easily and inexpensively manufactured using commercially available PVC pipes and their piping parts, and therefore does not require the use of siphon pipes with an M-shaped cross section even in recent years when they have been difficult to obtain.

[Third embodiment]
4 is a cross-sectional view showing a drainage device 11 according to a third embodiment. The drainage device 11 includes an air lift pump 50.

The air lift pump 50 can also be made using PVC pipes and their piping parts. The air lift pump 50 includes the inverted J-shaped siphon 40 of the second embodiment, excluding the elbow pipe 18 and elbow outlet pipe 32 at the lower end (referred to as the inverted J-shaped piping 51). In the second embodiment, the inverted J-shaped siphon 40 is obtained by adding the elbow pipe 18 and elbow outlet pipe 32 to the inverted J-shaped piping 51. The inverted J-shaped piping 51 of this embodiment does not necessarily perform a siphoning action, but for convenience of explanation, the piping that constitutes the inverted J-shaped piping 51 will be referred to as the first siphon pipe 41, etc., as in the second embodiment.

The air lift pump 50 also includes an air intake pipe 52 inserted into the portion upstream of the highest portion of the inverted J-shaped piping 51. The air intake pipe 52 is a pipe for supplying air to that portion, and forms part of the air intake device. The air intake device includes an air source (e.g., an air tank or an air compressor) that supplies air to the air intake pipe 52, a solenoid valve provided between the air source and the air intake pipe 52, and a controller that controls the solenoid valve. In this embodiment, the air intake pipe 52 is watertightly passed through the second elbow pipe 44 and inserted coaxially into the third siphon pipe 45 from above.

In this embodiment, the position of the lower end of the air supply pipe 52, where the air outlet is located, is set to be equal to the drainage end level L3. The lower end of the air supply pipe 52 is located slightly higher than the lower end of the third siphon pipe 45.

In this embodiment, when the water level in the drainage tank 10 rises and reaches the drainage start level L2, drainage begins, the solenoid valve of the air supply device is turned on, i.e., opened, and air is supplied from the lower end outlet of the air supply pipe 52. Then, air bubbles are mixed into the water in the third siphon pipe 45, which is located above the lower end outlet of the air supply pipe 52, and the specific gravity of the resulting two-phase flow becomes lighter than the specific gravity of the surrounding water at the same level.

As a result, like a normal air lift pump, the water or two-phase flow rises in the third siphon pipe 45, then flows down inside the first siphon pipe 41, etc., and is finally discharged into the drainage container 37. As water continuously flows into the third siphon pipe 45, the water levels in the drainage tank 10 and the water storage tank 2 gradually drop. As with a normal air lift pump, the water supply from the water supply pipe 14 is automatically stopped immediately after drainage begins.

When the water level eventually reaches the drainage end level L3, the solenoid valve of the air supply device is turned off, i.e. closed, and the air supply from the air supply pipe 52 is stopped. This ends the drainage.

Regarding the control of the solenoid valve of the air supply device, it is preferable to have a water level sensor to detect when the water level reaches the drain start level L2 and the drain end level L3. However, the drain start timing and drain end timing do not necessarily have to be simultaneous when the water level reaches the drain start level L2 and the drain end level L3, and may vary slightly. For example, since the time from the start of water supply to the start of drainage (called the water supply time) can be known in advance, the solenoid valve may be turned on when the water supply time has elapsed since the start of water supply. In addition, since the time from the start of drainage to the end of drainage (called the drain time) can also be known in advance, the solenoid valve may be turned off when the drain time has elapsed since the start of drainage.

In this embodiment, the drainage device 11 also includes an air lift pump 50, so that it is possible to provide a bottom irrigation device 100 for raising seedlings that is equipped with a suitable drainage device 11 that replaces the conventional M-shaped cross-section siphon pipe. In particular, the air lift pump 50 can be manufactured easily and inexpensively using commercially available PVC pipes and their piping parts, and therefore does not require the use of M-shaped cross-section siphon pipes even in recent years when they have become difficult to obtain.

In this embodiment, if at least an elbow pipe 18 is added to the inverted J-shaped piping 51, it becomes substantially similar to the inverted J-shaped siphon 40, so there is a possibility that it can also provide the same siphon action as in the second embodiment.

[Fourth embodiment]
5 is a cross-sectional view showing a drainage device 11 according to a fourth embodiment. The drainage device 11 includes a rotating curved pipe 55 that functions as both a drain pipe and an overflow pipe.

In this embodiment, a drain hole 56 is provided at the lower end of the side plate 13 located near the bottom plate 12 of the drainage tank 10. A rotating curved pipe 55 is connected to this drain hole 56 and attached to the outer surface of the side plate 13 so as to be rotatable around a rotation axis C1. The rotation axis C1 is coaxial with the center of the drain hole 56.

The rotating bend 55 can also be made using PVC pipes and their piping parts. The rotating bend 55 comprises a flange pipe 58 whose base end or upstream end is rotatably supported by a support member 57, an elbow pipe 59 whose upstream end is connected to the tip end or downstream end of the flange pipe 58, and an outlet pipe 60 whose upstream end is connected to the downstream end of the elbow pipe 59.

The flange pipe 58 is a straight pipe that has a flange 61 integral with its base end and extends coaxially with the rotation axis C1. The support member 57 is fixed to the outer surface of the side plate 13 while covering the flange 61, and supports the flange pipe 58 so that it can rotate around the rotation axis C1. The space between the support member 57 and the flange pipe 58 is watertightly sealed by a seal member (e.g., an O-ring) 62.

The elbow pipe 59 is a curved pipe bent 90 degrees, and the outlet pipe 60 is a short straight pipe. The method of connecting the flange pipe 58, elbow pipe 59, and outlet pipe 60 is the same as described above. The solid lines in the illustrated example show the water supply state when the rotating curved pipe 55 functions as an overflow pipe, and at this time, the outlet pipe 60 is facing upward. The position of the upper end outlet of the outlet pipe 60 is set to be equal to the drainage start level L2.

On the other hand, the imaginary line in the illustrated example shows the drainage state when the rotating bend 55 functions as a drain pipe, and at this time the rotating bend 55 is rotated 180° around the rotation axis C1 from the position in the water supply state, and the outlet pipe 60 is facing downward. The position of the bottom end of the drain hole 56 is set to be equal to the drainage end level L3.

In this embodiment, the rotating bent pipe 55 can function as an overflow pipe, so the overflow pipe 36 present in the first embodiment is omitted, and the overflow start level L4 is made to coincide with the drainage start level L2. However, to be on the safe side, the overflow pipe 36 may be provided separately.

When supplying water, the rotating bend pipe 55 is in the water supply state. When the water level in the drainage tank 10 rises during this water supply and reaches the drainage start level L2, drainage begins. The water in the drainage tank 10 flows from the drain hole 56 into the flange pipe 58, passes through the elbow pipe 59 and the outlet pipe 60, and is discharged from the upper end outlet of the outlet pipe 60. This causes overflow, and the rise in the water level is stopped. Immediately after drainage begins, the water supply from the water supply pipe 14 is automatically stopped.

Then, the rotating bend pipe 55 is rotated automatically or manually by an actuator to enter the draining state. The water in the drainage tank 10 then follows the same path as before and is discharged from the lower end outlet of the outlet pipe 60, and the water level in the drainage tank 10 gradually drops. When the water level eventually reaches the drainage end level L3, drainage automatically stops.

In this embodiment, the drainage device 11 also includes a rotating bent pipe 55, so that it is possible to provide a bottom irrigation device 100 for raising seedlings that is equipped with a suitable drainage device 11 that replaces the conventional M-shaped cross-section siphon pipe. In particular, the rotating bent pipe 55 can be made easily and inexpensively using commercially available PVC pipes and their piping parts, so that it is not necessary to use M-shaped cross-section siphon pipes even in recent years when they have become difficult to obtain.

[Fifth embodiment]
6 is a cross-sectional view showing a drainage device 11 according to a fifth embodiment. The drainage device 11 includes a drain cap 65 having a function of an overflow pipe.

In this embodiment, a drain hole 56 is provided at the lower end of the side plate 13 located near the bottom plate 12 of the drainage tank 10. A drain pipe 66 is fixedly attached to the outer surface of the side plate 13, coaxially communicating with the drain hole 56. Reference symbol C2 indicates the central axis of the drain hole 56 and the drain pipe 66. The drain pipe 66 is a straight pipe with a square cross section (horizontally elongated rectangle) that extends horizontally and has a flange 67 integrally formed at its base end (see FIG. 7). The flange 67 is fixed to the side plate 13, thereby fixing the drain pipe 66 to the side plate 13. The drain hole 56 and the drain pipe 66 form the drain outlet of the drainage tank 10.

A drain cap 65 is removably attached to the tip of this drain pipe 66. The drain cap 65 is an L-shaped pipe in side view as shown in Figure 6, and has a rectangular cross-sectional shape similar to that of the drain pipe 66 (see Figure 7). The drain cap 65 has an upstream horizontal section 68, a downstream vertical section 69, and a 90° bent section 70 that connects the horizontal section 68 and the vertical section 69.

The horizontal section 68 is fitted or pressed watertightly onto the outside of the drain pipe 66. A gasket 71 is provided on the tip surface of the horizontal section 68, which is pressed against the flange 67 to provide a watertight seal.

The vertical section 69 extends upward from the horizontal section 68. The position of the upper end outlet of the vertical section 69 is set to be equal to the drainage start level L2. Meanwhile, the position of the lower end of the drainage hole 56 is set to be equal to the drainage end level L3.

The drain cap 65 and drain pipe 66 of this embodiment can also be made using PVC pipes and their piping components.

The effect of this embodiment is similar to that of the fourth embodiment. When supplying water, the drain cap 65 is attached to the drain pipe 66 as shown in FIG. 6. When the water level in the drain tank 10 rises during water supply and reaches the drain start level L2, draining begins. The water in the drain tank 10 enters the drain pipe 66 from the drain hole 56, passes through the drain cap 65, and is discharged from the upper end outlet. This causes overflow, and the rise in the water level is stopped. Immediately after draining begins, the water supply from the water supply pipe 14 is automatically stopped.

The drain cap 65 is then removed automatically by an actuator or manually. At this time, the drain cap 65 is pulled out of the drain pipe 66 toward the right side in the figure. The water in the drain tank 10 is then discharged from the drain pipe 66, and the water level in the drain tank 10 gradually drops. When the water level eventually reaches the drain end level L3, drainage is automatically stopped.

In this embodiment, the drainage device 11 also includes the drain cap 65, so that it is possible to provide a bottom irrigation device 100 for raising seedlings that is equipped with a suitable drainage device 11 that replaces the conventional M-shaped cross-section siphon pipe. In particular, the drain cap 65 can be made from commercially available PVC pipes or their piping parts, so it can be made easily and inexpensively, and there is no need to use M-shaped cross-section siphon pipes even in recent years when they have been difficult to obtain.

Sixth Embodiment
8 is a cross-sectional view showing a drainage device 11 according to a sixth embodiment. The drainage device 11 includes a shutter valve 75.

In this embodiment, a drain hole 56 is provided at the bottom end of the side plate 13 adjacent to the bottom plate 12 of the drainage tank 10. This drain hole 56 is opened and closed by a shutter valve 75.

The shutter valve 75 is formed in a plate shape overlapped on the outer surface of the side plate 13. The material of the shutter valve 75 is arbitrary, and may be, for example, plastic or metal. The shutter valve 75 is guided between the outer surface of the side plate 13 and a guide member 76 attached thereto, and can slide up and down. A valve seat 77 is provided so as to extend the bottom plate 12 of the drainage tank 10. A packing 78 for a watertight seal is provided on the lower end surface of the shutter valve 75. When the drain hole 56 or the shutter valve 75 is closed as shown in the figure, the shutter valve 75 is positioned in a lowered position, and the packing 78 is pressed against the valve seat 77. On the other hand, when the drain hole 56 or the shutter valve 75 is opened, the shutter valve 75 is raised from the lowered position to the raised position. A tab 79 is provided on the upper end of the shutter valve 75 for applying a force when the shutter valve 75 is raised and lowered.

In this embodiment, an overflow pipe 36 is provided, as in the first embodiment. The drainage start level L2 is set at the same height as in the first embodiment. Meanwhile, the position of the bottom end of the drainage hole 56 is set to be equal to the drainage end level L3.

When supplying water, the shutter valve 75 is closed as shown in FIG. 8. When the water level in the drainage tank 10 rises during water supply and reaches the drainage start level L2, drainage begins. At this time, the shutter valve 75 is raised and opened automatically or manually by an actuator, and the water in the drainage tank 10 is drained from the drain hole 56. Immediately after drainage begins, the water supply from the water supply pipe 14 is automatically stopped.

After this, the water level in the drain tank 10 gradually drops. When the water level reaches the drain end level L3, drainage automatically stops.

In this embodiment, water is then supplied for a predetermined period of time with the shutter valve 75 open. The supplied water then washes away any foreign matter, such as dirt, that has accumulated at the bottom of the drainage tank 10, and the foreign matter is discharged together with the water from the drain hole 56. This allows the bottom of the drainage tank 10 to be periodically cleaned.

Once this cleaning is complete, the water supply is stopped and the shutter valve 75 is lowered and closed.

In this embodiment, the drainage device 11 also includes a shutter valve 75, making it possible to provide a bottom irrigation device 100 for raising seedlings that is equipped with a suitable drainage device 11 that can replace the conventional M-shaped cross-section siphon pipe. In particular, the shutter valve 75 has a simple structure and can be easily and inexpensively manufactured from general-purpose materials. Therefore, it is not necessary to use an M-shaped cross-section siphon pipe even in recent years when it has become difficult to obtain it.

Although the embodiment of the present disclosure has been described in detail above, various other embodiments and variations of the present disclosure are conceivable. For example, the seedling container is not limited to the cell tray 1, but may be a cell pot, etc.

The configurations of the above-described embodiments and variations can be combined in part or in whole, unless there is a particular contradiction. The embodiments of the present disclosure are not limited to the above-described embodiments, and all variations, applications, and equivalents encompassed within the concept of the present disclosure as defined by the scope of the utility model claims are included in the present disclosure. Therefore, the present disclosure should not be interpreted in a restrictive manner, and can be applied to any other technology that falls within the scope of the concept of the present disclosure.

1 Cell tray 2 Water tank 10 Drainage tank 11 Drainage device 15 Bell siphon 100 Seedling bottom irrigation device L2 Drainage start level

Claims (1)

A water tank for storing water for bottom irrigation of seedling containers;
a drainage tank that is connected to the water tank and stores water at the same level as the water tank;
A drainage device installed in the drainage tank for draining water from the drainage tank;
Equipped with
The bottom watering device for seedlings, wherein the drainage device includes a bell siphon that automatically starts draining when the water level in the drainage tank rises to a predetermined drainage start level.

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