JP7780989B2 - Discharge System - Google Patents

Description

The present invention relates to a discharge system.

Ocean fertilization devices have been proposed that pump seawater rich in nutrients from deeper areas and spread it to the surface, with the aim of enriching surface seawater with nutrients and creating new fishing grounds.

For example, the deep-sea water pumping and diffusion device disclosed in Patent Document 1 comprises a submersible float that floats below the surface of the euphotic zone and an upwelling pipe that extends from the submersible float to the seabed. In this pumping and diffusion device, an impeller installed inside the submersible float is rotated by a steam turbine device, thereby pumping up deep-sea water, sucking in surface water, and discharging a mixture of deep and surface water.

The ocean fertilization device in Patent Document 2 comprises a float moored to the ocean surface and a deep-sea water intake pipe extending from the float to the seabed. In this ocean fertilization device, a watertight electric motor rotates an impeller installed inside the float to pump up deep-sea water, suck in surface water, and discharge mixed water of deep and surface water. The electric motor is driven by electricity generated by an internal combustion engine or the like installed inside the float.

The deep-sea water pumping device of Patent Document 3 comprises a deep-sea water pumping unit suspended in the sea from a float, a hose extending from the deep-sea water pumping unit to the seabed, and an outer screw attached to the outside of the deep-sea water pumping unit. In this deep-sea water pumping device, the outer screw is rotated by the tidal current, which in turn rotates an inner screw installed inside the deep-sea water pumping unit, thereby pumping up deep sea water.

Japanese Patent Application Laid-Open No. 2000-27748 Japanese Patent Application Laid-Open No. 2002-370690 JP 2012-90619 A

In the pumping and diffusion device of Patent Document 1, it is proposed that steam for the steam turbine device that rotates the impeller be generated using energy from the temperature difference between surface water and the pumped-up deep water (so-called ocean thermal energy). Furthermore, in the ocean fertilization device of Patent Document 2, it is proposed that electricity for the electric motor that rotates the impeller be obtained from ocean thermal energy conversion, wind power, etc.

However, in order to utilize ocean thermal energy, deep-sea water must first be pumped up, necessitating a steam turbine device to rotate the impeller and an internal combustion engine to drive the electric motor. Furthermore, when using wind power generation, wind power must be converted into electricity, and then that electricity must be converted into kinetic energy to rotate the impeller, resulting in low energy utilization efficiency and making it difficult to ensure a stable energy supply. Therefore, a steam turbine device to rotate the impeller and an internal combustion engine to drive the electric motor are still required.

Meanwhile, Patent Document 3 describes how deep-sea water can be pumped up without using an electric pump by using tidal currents to rotate the outer and inner screws. However, the outer screw is a horizontal-axis propeller with a horizontal rotation axis, and when the tidal currents around the propeller reverse direction due to tides, the propeller's rotation direction also reverses. This means that the propeller is less able to follow changes in the water flow around it, which could result in reduced efficiency in pumping deep-sea water. Furthermore, because the water flow around the propeller caused by waves (i.e., the movement of the particles that make up the waves (orbital motion)) is opposite at the crests and troughs of the waves, it is difficult to use the wave-driven seawater flow to pump deep-sea water with this propeller. This also raises the risk of reduced efficiency in pumping deep-sea water.

The present invention was developed in consideration of the above-mentioned problems, and aims to efficiently pump up seawater from areas deeper than the surface by efficiently utilizing the flow of seawater.

The invention described in claim 1 is a discharge system comprising a floating body moored by mooring lines and floating on the sea surface; a water intake pipe extending downward from the floating body and having a water intake at its lower end; and a vertical-axis water turbine attached to the floating body, located below the sea surface, and rotating in only one circumferential direction around a central axis facing up and down. The water turbine has a water turbine channel connected to the water intake pipe and having an outlet at its radially outer end. When the water turbine rotates due to the flow of seawater, seawater in the water turbine channel is discharged from the outlet by centrifugal force, and seawater near the water intake is guided into the water turbine channel via the water intake pipe.

The invention described in claim 2 is the discharge system described in claim 1, wherein the floating body is columnar and centered on the central axis, and the water turbine is provided on the side of the floating body.

The invention described in claim 3 is the discharge system described in claim 2, wherein the water turbine is a propeller-type water turbine having multiple blades arranged circumferentially and each protruding radially outward from the side of the floating body.

The invention described in claim 4 is the discharge system described in claim 3, wherein each of the multiple blades is curved so that the radial center portion is convex toward the rotation direction of the water turbine.

The invention described in claim 5 is the discharge system described in claim 3 or 4, wherein the turbine flow path is provided inside each of the plurality of blades, and the discharge port is provided on the edge of each of the plurality of blades.

The invention described in claim 6 is a discharge system described in any one of claims 1 to 5, wherein at least the portion of the floating body above the sea surface is independent of the rotation of the water turbine.

The invention described in claim 7 is the discharge system described in claim 6, in which the entire floating body is independent of the rotation of the water turbine.

The invention described in claim 8 is a discharge system described in any one of claims 1 to 7, further comprising a power generation device that generates electricity using the flow of seawater around the floating body, and a pump that is driven by the electricity generated by the power generation device and assists in the upward movement of seawater in the water intake pipe.

This invention makes efficient use of the flow of seawater to efficiently pump up seawater from areas deeper than the surface.

FIG. 1 is a side view of a discharge system according to one embodiment. FIG. FIG. FIG. FIG. FIG. FIG. 10 is a plan view of a floating body equipped with another water turbine.

Figure 1 is a side view showing the configuration of a release system 1 according to one embodiment of the present invention. Release system 1 is a floating ocean fertilization device that is moored in a fishing area or other sea area and uses deep seawater (so-called deep ocean water) that is rich in nutrients from an area deeper than the surface to eutrophicate the surface layer. Release system 1 can be used as a floating fish reef with ocean fertilization functions.

The discharge system 1 comprises a float 2 and a water intake pipe 3. The float 2 is a structure floating on the sea surface 91 at a distance above the seabed 92. The float 2 is moored to the seabed 92 by a mooring line 41. In the example shown in Figure 1, the float 2 is a generally columnar structure extending vertically through the sea surface 91, and is connected via the mooring line 41 to a mooring base 42 installed on the seabed 92.

The mooring base 42 may be, for example, a sinker (i.e., a weight) or an anchor (i.e., an anchor with holding power) sunk into the seabed 92. Alternatively, the mooring base 42 may be a fixed structure that has been installed on the seabed 92 in advance. The mooring base 42 does not necessarily have to be directly fixed to the seabed 92; for example, it may be an object that is indirectly fixed to the seabed 92 in the sea via another structure fixed to the seabed 92.

The mooring line 41 is a generally linear member that connects the float 2 to the mooring base 42. The mooring line 41 is, for example, a mooring rope, a mooring chain, or a mooring chain connected to a mooring rope. The mooring rope is, for example, a rope made of synthetic fiber or metal containing wire. In Figure 1, the mooring line 41 is shown as a line for ease of illustration. In the example shown in Figure 1, the float 2 is moored at one point to the mooring base 42 by a single mooring line 41 connected to the lower end of the float 2. Note that the float 2 may also be moored at multiple points.

The intake pipe 3 is a generally cylindrical member that extends downward from the lower end of the floating body 2 toward the seabed 92, and is also called a riser pipe. An intake port 31 for taking in deep seawater is provided at the lower end of the intake pipe 3. The intake pipe 3 is primarily made of steel. The vertical length of the intake pipe 3 is, for example, 100 m to 1000 m. The diameter (i.e., outer diameter) of the intake pipe 3 is, for example, 0.25 m to 1.5 m. The material, length, and diameter of the intake pipe 3 may be varied in various ways.

Figure 2 is a side view showing the float 2 of the discharge system 1. Figure 3 is a plan view of the float 2. Figure 4 is a cross-sectional view of the float 2 taken at position IV-IV in Figure 2. Figure 5 is a longitudinal cross-sectional view of the float 2 taken at position V-V in Figure 4. Figures 2 and 5 also show a portion of the water intake pipe 3. Furthermore, to make the drawings easier to understand, in Figures 4 and 5, only the seawater inside the float 2 is shaded, and the cross section of the float 2 is not shaded.

The float 2 comprises a float main body 21 and a water turbine 22. The float main body 21 is a generally columnar structure extending vertically through the sea surface 91 (see Figure 1). In the example shown in Figure 2, the float main body 21 is a generally cylindrical structure extending vertically around a central axis J1. The central axis J1 is an imaginary straight line extending vertically. The float main body 21 is primarily made of steel. The vertical length of the float main body 21 is, for example, 4m to 10m. The diameter of the float main body 21 is, for example, 3m to 7m. The vertical length of the portion of the float main body 21 protruding above the sea surface 91 (i.e., freeboard) is, for example, 0.5m to 4m. The size and shape of the float main body 21 are not limited to the above example and may be modified in various ways.

The above-mentioned water intake pipe 3 is attached, for example, at approximately the center in the radial direction (hereinafter simply referred to as the "radial direction") centered on the central axis J1 at the lower end of the floating body main body 21. Furthermore, the mooring line 41 (see Figure 1) is connected, for example, at the radially outer end of the lower end of the floating body main body 21, to a portion in the circumferential direction (hereinafter simply referred to as the "circumferential direction") centered on the central axis J1.

The water turbine 22 is attached to the floating body main body 21 below the sea surface 91. In the example shown in Figure 2, the water turbine 22 is provided on the side of the floating body main body 21 (i.e., the approximately cylindrical side surface on the radially outer side), above the water intake pipe 3 and mooring line 41 (see Figure 1). The water turbine 22 is rotatable along the side of the floating body main body 21 around a central axis J1 facing in the vertical direction. In other words, the water turbine 22 is a vertical-axis water turbine rotatably attached to the floating body main body 21. The water turbine 22 is mainly made of steel.

The water turbine 22 rotates in only one circumferential direction due to the force acting from the seawater flowing around the floating body 21. In the example shown in Figure 3, the water turbine 22 rotates only clockwise in a plan view, and does not rotate counterclockwise, regardless of the direction of the seawater flowing around the floating body 21. The flow of seawater around the floating body 21 includes "ocean currents" such as the Kuroshio Current, which always flow in approximately the same direction, "tidal currents (also called tidal currents)" that occur with the ebb and flow of the tides, "wind-driven currents" that occur due to wind blowing over the ocean, and seawater flow caused by waves. The direction of tidal currents changes approximately twice a day due to repeated low and high tides. The direction of wind-driven currents changes depending on the direction of the wind blowing over the ocean. The wave-driven seawater flow (i.e., the movement of particles that make up the wave (orbital motion)) is opposite when the floating body 2 is located at a wave crest and when it is located at a wave trough. As mentioned above, the water turbine 22 is a vertical axis type, so regardless of changes in the direction of the seawater flow around the floating body 21, it continues to rotate in the same direction by efficiently utilizing the energy of the seawater flow.

The water turbine 22 is a vertical-axis propeller-type water turbine equipped with a boss portion 221 and multiple blades 222. The boss portion 221 is a substantially cylindrical portion extending substantially vertically around the central axis J1 and is rotatably attached to the side of the floating body main body 21. The multiple blades 222 are connected to the outer surface of the boss portion 221 and extend radially outward from the outer surface. In other words, the multiple blades 222 of the water turbine 22 each protrude radially outward from the side of the floating body main body 21. Each of the multiple blades 222 is a substantially plate-shaped member extending substantially parallel in the vertical direction. The multiple blades 222 are arranged circumferentially at substantially equal angular intervals. In the example shown in Figure 3, four blades 222 are arranged circumferentially at approximately 90° intervals. The number of blades 222 is not limited to four and may be changed as appropriate. Furthermore, each blade 222 does not necessarily need to extend substantially parallel to the vertical direction; it may extend at an angle relative to the vertical direction.

The radial size of each blade 222 (i.e., the radial distance between the connection point of the blade 222 with the boss portion 221 and the radial outer end of the blade 222 in a plan view) is, for example, 1 m to 2 m. The vertical size of each blade 222 (i.e., the height of the blade 222) is, for example, 2 m to 3 m.

The connection portion of each blade 222 with the boss portion 221 is preferably located forward in the rotation direction (i.e., clockwise direction) of the water turbine 22 in plan view relative to the edge of each blade 222 (i.e., the free edge opposite the connection portion). Furthermore, each blade 222 is preferably curved in a generally arc shape so that its radial center portion is convex in the rotation direction of the water turbine 22 in plan view. In other words, the connection portion of each blade 222 with the boss portion 221 and the radial center portion of each blade 222 are preferably located forward in the rotation direction of the water turbine 22 relative to the straight line connecting the edge of each blade 222 and the central axis J1 in plan view.

In the water turbine 22, the size and shape of the multiple blades 222 are preferably approximately the same. This simplifies the manufacture of the water turbine 22. Note that the size and shape of each blade 222 are not limited to the above example and may be modified in various ways. Furthermore, the size and/or shape of the multiple blades 222 do not necessarily have to be the same and may be different.

The upper end of the water turbine 22 is located, for example, 3 to 5 meters below the sea surface 91. Furthermore, at least the portion of the floating body 21 above the sea surface 91 is preferably independent of the rotation of the water turbine 22 and does not follow the rotation of the water turbine 22 caused by the flow of seawater acting on the water turbine 22. This allows ships approaching the floating body 2 to easily come alongside the upper part of the floating body 21, which barely rotates, without coming into contact with the rotating water turbine 22. Furthermore, it is more preferable that the entire floating body 21 is independent of the rotation of the water turbine 22 and does not follow the rotation of the water turbine 22 caused by the flow of seawater acting on the water turbine 22. This also makes the mooring line 41 and water intake pipe 3 connected to the lower part of the floating body 21 independent of the rotation of the water turbine 22. This facilitates mooring the floating body 2 to the seabed 92 and simplifies the connection structure between the floating body 21 and the water intake pipe 3.

In the float 2 illustrated in FIG. 5 , a substantially cylindrical recess 211 (hereinafter also referred to as the "main body recess 211") extending substantially vertically around the central axis J1 is provided on the side of the float main body 21. The diameter of the side of the float main body 21 in the area where the main body recess 211 is provided (hereinafter also referred to as the "recess side surface 212") is smaller than the diameter of the side surface of the float main body 21 above the main body recess 211 and the diameter of the side surface of the float main body 21 below the main body recess 211. A boss portion 221 is fitted into the main body recess 211. The diameter of the inner surface of the boss portion 221 is larger than the diameter of the recess side surface 212. Therefore, a substantially cylindrical gap (hereinafter also referred to as the "outer buffer space 214") extending substantially vertically around the central axis J1 is formed between the inner surface of the boss portion 221 and the recess side surface 212 of the float main body 21.

The diameter of the inner surface of the boss portion 221 is smaller than the diameter of the side surface of the portion of the float body 21 above the main body recess 211 and the diameter of the side surface of the portion below the main body recess 211. The upper and lower end surfaces of the boss portion 221 face up and down, respectively, to the upper and lower surfaces of the main body recess 211 of the float body 21. Bearings 213 are provided between the upper end surface of the boss portion 221 and the upper surface of the main body recess 211, and between the lower end surface of the boss portion 221 and the lower surface of the main body recess 211, respectively, and the water turbine 22 is rotatably supported on the float body 21 via these bearings 213. The gap between the upper end surface of the boss portion 221 and the upper surface of the main body recess 211, and the gap between the lower end surface of the boss portion 221 and the lower surface of the main body recess 211 are watertightly sealed. This isolates the outer buffer space 214 from the space surrounding the boss portion 221 and the floating body main body 21, preventing surface seawater from entering the outer buffer space 214.

In the example shown in Figures 4 and 5, the outer buffer space 214 is connected to the inner buffer space 216 via multiple connecting channels 215 that extend radially inside the floating body main body 21. The inner buffer space 216 is a space located radially inward of the outer buffer space 214 and the multiple connecting channels 215. The inner buffer space 216 is, for example, a substantially cylindrical space extending substantially vertically around the central axis J1, and is located above the water intake pipe 3. The lower end of the inner buffer space 216 is connected to the upper end of the water intake pipe 3, and the inner buffer space 216, the multiple connecting channels 215, and the outer buffer space 214 are filled with deep seawater taken in from the water intake port 31 of the water intake pipe 3 (see Figure 1).

A turbine channel 223 is provided inside each blade 222 of the turbine 22. The turbine channel 223 extends along the front and rear side surfaces of the blade 222 in the rotational direction from the end edge (i.e., the free edge) of the blade 222 to the connection point with the boss portion 221 of the blade 222. The turbine channel 223 extends, for example, from the upper end to the lower end of the blade 222. The turbine channel 223 penetrates the boss portion 221 at its radially inner end and connects to the outer buffer space 214. The turbine channel 223 is connected to the intake pipe 3 via the outer buffer space 214, multiple connecting channels 215, and the inner buffer space 216, and the turbine channel 223 is filled with deep seawater taken in from the intake port 31 of the intake pipe 3 (see Figure 1).

The turbine flow path 223 opens toward the outside of the blade 222 (i.e., the outside of the floating body 2) at the edge of the blade 222. In the following description, the opening provided at the edge of the blade 222 is also referred to as the "discharge port 224." The discharge port 224 is located at the radially outer end of the turbine flow path 223 and also at the radially outer end of the turbine 22. The discharge port 224 is, for example, a substantially slit-shaped opening extending in the vertical direction from the upper end to the lower end of the edge of the blade 222. The shape of the discharge port 224 may be changed as appropriate. For example, the edge of the blade 222 may be provided with multiple circular or other discharge ports arranged in the vertical direction. The turbine flow path 223 is not open on the surface of the blade 222 other than the discharge port 224 (for example, at the upper or lower end of the blade 222).

In the discharge system 1, when the water turbine 22 rotates due to the flow of seawater around the floating body 21, deep seawater in the turbine flow path 223 of each blade 222 is discharged radially outward from the discharge port 224 by centrifugal force. In parallel with the discharge of deep seawater from each discharge port 224, deep seawater flows from the outer buffer space 214 into each turbine flow path 223, and deep seawater flows into the outer buffer space 214 from the inner buffer space 216 via multiple connecting flow paths 215. Furthermore, deep seawater taken in from the intake 31 flows into the inner buffer space 216 via the intake pipe 3. In other words, when the water turbine 22 rotates on the floating body 2, deep seawater is discharged from each discharge port 224, and deep seawater near the intake 31 is pumped up via the intake pipe 3 and guided into the turbine flow path 223.

In the discharge system 1 according to this embodiment, it is preferable not to provide a pump for drawing up deep seawater through the intake pipe 3, or a power generation device (e.g., a generator such as a diesel engine that uses fuel oil) for driving the pump.

In the discharge system 1, deep seawater (i.e., seawater rich in nutrients) discharged radially from the outlets 224 of the multiple blades 222 around the floating body 2 is dispersed over a wide area in the surface layer as a density current. This eutrophicates the surface layer and creates new fishing grounds. Note that in the above explanation, the seawater discharged from each outlet 224 is only deep seawater pumped up by the intake pipe 3, but this is not limited to this. For example, deep seawater pumped up by the intake pipe 3 and surface seawater taken in from around the floating body 21 may be mixed inside the floating body 21 (e.g., the internal buffer space 216) to form mixed seawater, and this mixed seawater may then be discharged from each outlet 224.

In the discharge system 1, the turbine flow path 223 does not necessarily have to be located inside the blades 222 of the turbine 22. Furthermore, the vertical-axis turbine 22 installed on the floating body 2 is not limited to a propeller type, and may have other structures, such as a crossflow type, Saponius type, Darrieus type, or gyromill type. For example, on the upper surface of a substantially cylindrical crossflow turbine extending substantially vertically around the central axis J1, multiple pipelines (e.g., substantially circular tubular metal piping) extending radially outward from the central axis J1 may be installed, and each of these multiple pipelines may serve as the turbine flow path 223. In this case, the radially inner end of each pipeline is connected to the intake pipe 3 via the above-mentioned internal buffer space 216, etc., and the radially outer end of each pipeline serves as the discharge port 224 located at the radially outer end of the turbine 22.

As described above, the discharge system 1 comprises a floating body 21, a water intake pipe 3, and a vertical-axis water turbine 22. The floating body 21 is moored by a mooring line 41 and floats on the sea surface 91. The water intake pipe 3 extends downward from the floating body 21. The water intake pipe 3 has a water intake port 31 at its lower end. The water turbine 22 is attached to the floating body 21 and is located below the sea surface 91. The water turbine 22 rotates in only one circumferential direction around a central axis J1 facing up and down. The water turbine 22 is provided with a water turbine flow path 223. The water turbine flow path 223 is connected to the water intake pipe 3. The water turbine flow path 223 has a discharge port 224 at its radially outer end. In the discharge system 1, the flow of seawater causes the water turbine 22 to rotate, causing the seawater in the water turbine flow path 223 to be discharged from the discharge port 224 by centrifugal force, and seawater near the water intake 31 is guided into the water turbine flow path 223 via the water intake pipe 3.

In this way, the discharge system 1 is provided with a vertical-axis water turbine 22 that rotates in only one circumferential direction, utilizing the flow of seawater around the floating body main body 21, regardless of the direction of the seawater flow. This allows the water turbine 22 to rotate efficiently by utilizing the flow of seawater, even if the direction of the seawater flow fluctuates. Specifically, the discharge system 1 can efficiently utilize not only ocean currents that flow in approximately the same direction, but also tidal currents, wind-driven currents, and seawater flows caused by waves, which change direction, to rotate the water turbine 22.

Furthermore, the discharge system 1 uses centrifugal force generated by the rotation of the water turbine 22 to discharge seawater in the turbine channel 223 around the floating body 2, and can efficiently pump up nutrient-rich seawater (i.e., deep seawater) from areas deeper than the surface and supply it to the turbine channel 223. Therefore, pumps for pumping seawater through the intake pipe 3 and power generation equipment for driving the pumps can be omitted from the discharge system 1, simplifying the configuration and maintenance of the discharge system 1. Furthermore, even if such pumps and power generation equipment are installed, the amount of fuel oil and other materials used to drive the power generation equipment can be reduced. As a result, the costs required for manufacturing and/or operating the discharge system 1 can be reduced.

As described above, the floating body main body 21 is preferably columnar, centered on the central axis J1, and the water turbine 22 is provided on the side of the floating body main body 21. This allows the water turbine 22 to be positioned near the sea surface 91 while preventing the float 2 from becoming too large. As a result, nutrient-rich deep seawater can be dispersed into the surrounding area from the outlet 224 of the water turbine 22, which is located near the sea surface 91, thereby effectively realizing eutrophication of the surface layer.

As mentioned above, the water turbine 22 is preferably a propeller-type water turbine having multiple blades 222 arranged circumferentially and each protruding radially outward from the side of the floating body 21. This allows the flow of seawater around the floating body 21 to be efficiently used to rotate the water turbine 22. As a result, deep seawater can be efficiently pumped up.

As mentioned above, it is preferable that each of the multiple blades 222 be curved so that the radial center portion is convex toward the rotation direction of the water turbine 22. This allows the flow of seawater around the floating body main body 21 to be used more efficiently to rotate the water turbine 22. As a result, deep seawater can be pumped up even more efficiently.

As described above, the turbine flow path 223 is preferably provided inside each of the multiple blades 222. Furthermore, the discharge port 224 is preferably provided on the edge of each of the multiple blades 222. This allows the turbine 22 to be made smaller than when the turbine flow path 223 is provided outside the blades 222. As a result, the floating body 2 and discharge system 1 can be made smaller.

As described above, in the discharge system 1, it is preferable that at least the portion of the floating body 21 above the sea surface 91 is independent of the rotation of the water turbine 22. This makes it easier for ships and other vessels to come alongside the floating body 21 and for workers to board the floating body 21. Furthermore, in the discharge system 1, it is even more preferable that the entire floating body 21 is independent of the rotation of the water turbine 22. As described above, this makes it easier to moor the floating body 2 to the seabed 92 and also simplifies the connection structure between the floating body 21 and the water intake pipe 3.

In the discharge system 1, as shown in FIG. 6, a pump 51 may be provided inside the floating body 21, and the pumping of deep seawater by the rotation of the water turbine 22 (i.e., the upward movement of seawater in the water intake pipe 3) may be assisted by the pump 51. The pump 51 may be, for example, an axial flow pump, and is disposed within the internal buffer space 216. The pump 51 is not used under normal conditions (i.e., when the pumping flow rate of deep seawater by the rotation of the water turbine 22 is equal to or greater than a predetermined flow rate), but is driven to assist in the pumping of deep seawater when the flow of seawater around the floating body 21 weakens and the pumping flow rate becomes insufficient. The type and location of the pump 51 are not particularly limited and may be selected as appropriate.

The pump 51 is driven by electricity generated by a power generation device 52 provided on the floating body 21. In the example shown in FIG. 6 , the power generation device 52 is disposed inside the floating body 21 and is mechanically connected to the water turbine 22 via gears, shafts, etc. (not shown). The power generation device 52 converts the rotational energy of the water turbine 22, which is generated by the flow of seawater around the floating body 21, into electrical energy. In other words, the power generation device 52 generates electricity by utilizing the flow of seawater around the floating body 21. The electricity generated by the power generation device 52 is stored in a storage battery 53 disposed inside the floating body 21. When the flow rate of deep seawater pumped by the rotation of the water turbine 22 falls below the predetermined flow rate, the electricity stored in the storage battery 53 is supplied to the pump 51, which drives the pump 51 and assists in pumping the deep seawater.

As such, it is preferable that the discharge system 1 further includes a power generation device 52 that generates electricity using the flow of seawater around the floating body 21, and a pump 51 that is driven by the electricity generated by the power generation device 52 and assists in the upward movement of seawater in the water intake pipe 3. This makes it possible to suppress or prevent a shortage of the pumped flow rate of deep seawater, even if the flow of seawater around the floating body 21 weakens. It is also preferable that the power generation device 52 generates electricity using the rotation of the water turbine 22. This simplifies the configuration related to the power generation.

It is preferable that power generation by the power generation device 52 is performed only when the pumping flow rate of deep seawater due to the rotation of the water turbine 22 is equal to or greater than a predetermined threshold value that is greater than the above-mentioned predetermined flow rate, and is stopped when the flow rate is less than the threshold value. As a result, when the flow of seawater around the floating body main body 21 is relatively weak, the seawater flow can be used only to pump up deep seawater, not to generate power. As a result, a shortage of the pumping flow rate of deep seawater can be effectively prevented.

The power generation device 52 does not necessarily have to generate power using the rotation of the water turbine 22. For example, a separate power generation water turbine other than the water turbine 22 may be attached to the floating body 21, and the rotational energy of the power generation water turbine, generated by the flow of seawater around the floating body 21, may be converted into electrical energy by the power generation device 52. Furthermore, the power generation device 52 may generate power using other renewable energy sources instead of or in addition to the flow of seawater around the floating body 21. Examples of such renewable energy sources include solar power, wind power, and/or the temperature difference between surface seawater and deep seawater (the so-called ocean temperature difference). Even in these cases, a shortage in the pumping flow rate of deep seawater can be suppressed or prevented in a manner similar to that described above.

Various modifications are possible to the above-described discharge system 1.

For example, in the water turbine 22, it is not necessary for all blades 222 to be provided with the turbine flow path 223 and the discharge port 224; the turbine flow path 223 and the discharge port 224 may be provided in only some of the multiple blades 222. Furthermore, the discharge port 224 does not necessarily have to be provided at the edge of the blade 222, as long as it is located at the radially outer end of the turbine flow path 223 provided inside the blade 222, and may be provided at a location other than the edge of the blade 222 (for example, a location radially inward from the edge on the front and/or rear side of the blade 222 in the rotational direction). In the water turbine 22, the turbine flow path 223 does not necessarily have to be provided inside the blade 222; it may be provided outside the blade 222. For example, a conduit (e.g., a substantially cylindrical metal pipe) extending along the upper edge of the blade 222 may be attached to the upper end of the blade 222, and this conduit may serve as the turbine flow path 223. In this case, the radially outer end opening of this conduit serves as the discharge port 224.

The water turbine 22 does not necessarily have to be attached to the side of the floating body 21, but may be attached to another part of the floating body 21. For example, the water turbine 22 may be attached to the lower end of the floating body 21 and positioned below the floating body 21 so as to surround the water intake pipe 3.

The shape and size of the floating body 21 are not limited to the above example and may be modified in various ways. Furthermore, the floating body 21 does not necessarily need to be independent of the rotation of the water turbine 22; for example, a portion of the floating body 21 (e.g., a portion below the sea surface 91) or the entire floating body 21 may be configured to rotate together with the water turbine 22, which rotates due to the flow of seawater around the floating body 21.

The shape of the water turbine 22 is not limited to the above example and may be modified in various ways. For example, as shown in Figure 7, a propeller-type water turbine 22a equipped with blades 222a having a different shape from the blades 222 may be attached to the side of the floating body main body 21 instead of the water turbine 22. In the water turbine 22a, multiple blades 222a extend radially outward from the outer surface of a boss portion 221 having approximately the same shape as in the above example. In other words, the multiple blades 222a each protrude radially outward from the side of the floating body main body 21. In the example shown in Figure 7, four blades 222a are arranged circumferentially at approximately 90° intervals. The multiple blades 222a are also approximately the same size and shape. The number of blades 222a is not limited to four and may be modified as appropriate.

Each blade 222a includes a first portion 225 and a second portion 226. The first portion 225 is a generally flat portion extending generally parallel to the vertical direction and extends generally linearly from the boss portion 221 along the radial direction in a plan view. The first portion 225 preferably extends generally parallel to the radial direction, but may extend in a direction inclined relative to the radial direction. The second portion 226 is a generally flat portion extending generally parallel to the vertical direction and is connected to the radially outer end of the first portion 225. In a plan view, the second portion 226 extends generally linearly from the radially outer end of the first portion 225 to the rear side in the rotational direction of the water turbine 22a. In a plan view, the angle between the first portion 225 and the second portion 226 of the blade 222a is, for example, approximately 90°. This angle may be varied in various ways. An outlet 224 similar to that described above is provided at the end of the second portion 226 opposite the first portion 225 (i.e., the edge of the blade 222a), and when the water turbine 22a rotates, deep seawater in the turbine flow path (not shown) provided inside each blade 222a is discharged to the surrounding area from the outlet 224 by centrifugal force. In the discharge system 1, even when the water turbine 22a is provided instead of the water turbine 22 (see Figure 3), the flow of seawater around the floating body 21 can be efficiently used to rotate the water turbine 22a, in a manner similar to that described above.

The configurations in the above embodiments and variations may be combined as appropriate as long as they are not mutually inconsistent.

REFERENCE SIGNS LIST 1 discharge system 3 water intake pipe 21 floating body main body 22, 22a water turbine 31 water intake port 41 mooring line 51 pump 52 power generation device 91 sea surface 222, 222a blade 223 water turbine channel 224 discharge port J1 central axis

Claims (8)

A discharge system comprising:
a floating body moored by a mooring line and floating on the sea surface;
a water intake pipe extending downward from the floating body and having a water intake port at its lower end;
a vertical axis type water turbine attached to the floating body, positioned below the sea surface, and rotating in only one circumferential direction around a central axis facing up and down;
Equipped with
The water turbine is provided with a water turbine flow path that is connected to the water intake pipe and has a discharge port at an end portion on the outer side in the radial direction,
A discharge system characterized in that, when the turbine rotates due to the flow of seawater, the seawater in the turbine flow path is discharged from the outlet by centrifugal force, and the seawater near the intake port is guided into the turbine flow path through the intake pipe. The discharge system according to claim 1,
The floating body has a columnar shape centered on the central axis,
A discharge system characterized in that the water turbine is provided on the side of the floating body. The discharge system according to claim 2,
A discharge system characterized in that the water turbine is a propeller-type water turbine having a plurality of blades that each protrude radially outward from the side of the floating body and are arranged circumferentially. The discharge system according to claim 3,
A discharge system characterized in that each of the plurality of blades has a radial center portion curved so as to be convex toward the rotation direction of the water turbine. The discharge system according to claim 3 or 4,
The turbine flow path is provided inside each of the plurality of blades,
The discharge system is characterized in that the discharge outlet is provided on an end edge of each of the plurality of blades. The discharge system according to any one of claims 1 to 5,
A discharge system characterized in that at least a portion of the floating body above the sea surface is independent of the rotation of the water turbine. The discharge system according to claim 6,
A discharge system characterized in that the entire floating body is independent of the rotation of the water turbine. 8. The discharge system according to claim 1,
a power generation device that generates power by utilizing the flow of seawater around the floating body;
a pump driven by the power generated by the power generation device to assist the upward movement of seawater in the water intake pipe;
The discharge system further comprises: