JPS6153556B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wave power generation device. In particular, the present invention relates to a wave power generation device using a floating body.

Wave power generation devices that generate electricity using ocean wave power as an energy source are broadly classified into two types: air turbine type and floating body type. The air turbine method is
An air piston chamber that opens downward is fixed and protrudes above the water surface, and the vertical movement of the water surface within the air piston chamber compresses and discharges the air in the chamber. This air operates an air turbine to generate electricity. It is. This method has the advantage that there are fewer moving parts and therefore fewer problems such as breakdowns during use, but the air pressure is 0.05 to 0.1 atm for a wave height of 1 m to 2 m (normally, wave height pressure of
The maximum output can be obtained at around 1/2), and at such a small pressure (normal power generation turbines have a pressure of 10 to 500 atmospheres), the area of the turbine blades, etc. increases in inverse proportion to the pressure. Because of this necessity, the engine has to be large, and it is practically difficult to create a highly efficient engine that can overcome frictional forces. Also,
The air reservoir for smooth operation is inevitably large, and the efficiency of using wave energy is not sufficient, and the equipment becomes large-scale and expensive.

On the other hand, the floating body method uses a floating body moored with a cable to operate a piston and cylinder to extract buoyant energy.The working fluid is water whose compressibility can be ignored, and the floating body By increasing the ratio between the effective cross-sectional area and the cylinder area, a pressure source with a high pressure of, for example, about 50 atm to 400 atm can be obtained. Therefore,
Theoretically, it has the advantage of converting wave energy into mechanical energy with high conversion efficiency.

By the way, in general, in order for a floating body floating on the sea surface to move up and down in a stable manner following the rise and fall of waves, a certain amount of tension must always be applied to the cable mooring the floating body to pull it downward or to a fixed point on the seabed. It is necessary to apply a restraining force. An example of a configuration in which a fluid piston/cylinder device is actuated by tension fluctuations occurring in this mooring cable is disclosed in Japanese Patent Application Laid-open No. 17437/1983.
There are devices described in JP-A-52-31247 and JP-A-54-163242, but these conventional floating body systems are all systems in which the floating body is restrained by the weight of the cable, and the floating body is restrained by the weight of the cable. The ability of the piston/cylinder device to follow motion is low, energy utilization efficiency is insufficient, and the restraint of the floating body is weak, resulting in low durability against waves. That is, Japanese Patent Application Publication No. 1973-
In the device disclosed in Publication No. 17437, a floating body is connected to a piston of a piston-cylinder device via an upper cable, and the cylinder of the piston-cylinder device is moored to the seabed via a lower cable. When the floating body moves up and down in response to the up and down movement of the floating body, the piston/cylinder device also moves up and down accordingly. When the piston and cylinder system rises with the rise of the floating body, the lower cable mooring the piston and cylinder device to the seabed becomes in a state where the slack is reduced as shown in Figure 5a, When the piston-cylinder device descends as it descends, it enters a state of increased slack as shown in FIG. 5b. In this case, the cable tension is caused by the cable's own weight, and the effective cable weight is the height below the piston/cylinder device shown in Figure 5 a and b (from the bottom of the piston/cylinder device to the mooring point on the seabed). vertical length). The change in the effective weight of the cable between the sagging state when the floating body is raised and the sagging state when it is lowered results in a change in tension, causing movement of the piston of the piston-cylinder device. In this method, most of the lift of the floating body is spent raising the piston-cylinder device, and only a small portion of the vertical movement of the floating body can actually be used for moving the piston. In addition, the cable mooring the cylinder to the seabed is left loose to prevent breakdowns and forms a catenary line, so the lateral restraining force on the floating body is only about 10 to 15% of the cable tension, and it is difficult to prevent waves such as typhoons. When the conditions are rough, the floating body swings violently and the floating body and cables are easily damaged.

Also, JP-A-52-31247 and JP-A-54-
Publication No. 163242 discloses a wave power generation device in which water is pumped up to a reservoir on land using a pump operated by a floating body, and a water turbine generator is operated by the drop from the reservoir. The lift pump shown in Figure 2 simply fixes the lower surface of the cylinder of the piston-cylinder device to the seabed and connects the piston to the floating body mooring cable, so it effectively acts as a downward force on the piston when the floating body descends. is only the weight of the piston,
In reality, due to the frictional forces between the cylinder and the piston, the piston cannot lower or only moves slightly. Therefore, the energy utilization efficiency is extremely low because the cable becomes loose when the wave descends and the wave energy cannot be extracted until the cable becomes taut during the subsequent ascent. Also,
When the waves descend, the cable becomes loose and loses its binding force on the floating body, making it more likely that the floating body and cable will be damaged or destroyed by the impact of the waves.

As mentioned above, in order to achieve sufficient energy utilization efficiency with the floating body system, when the floating body descends, an appropriate downward force is applied to the piston to maintain the cable in a tensioned state, and the floating body is also restrained in the lateral direction. However, providing a tension spring as a means for this purpose has many difficulties, such as the durability of the spring.

Further, a water wheel type power generation device is used in the wave power generation device, but a high water pressure source is required to generate a water flow to pass through the turbine of this water wheel type power generation device. When the device is constructed as a completely submerged type, it is conceivable to use the water head pressure due to the difference in height between the free water surface and the installation position of the power generating device as the high water pressure source. In this configuration, the wave energy extracted by the floating body will be used to drive a drain pump to keep the water level at the turbine drain low. Utility Model Publication No. 53-24624 discloses such an underwater power extraction device. The device disclosed in this publication is configured such that a turbine is disposed inside a cylindrical casing and installed underwater, and water around the casing is guided to the turbine, and drainage inside the casing is handled by a drainage pump operated by a floating body. It is configured to be ejected. In the structure disclosed as an example in this publication, the piston rod of the drainage pump is directly attached to the floating body, but if this principle of underwater power extraction is adopted for wave power generation, it will be necessary to construct a large-scale power generation base. For example, when constructing a power plant with an average output of 10,000 kW and a maximum output of 40,000 kW, if a spherical floating body with a typical diameter of 2 m is used, the wave height will be 0.8 to 1.2 m and the cycle period will be 6.
It is possible to generate power of 0.8 to 1.3kw per floating body for ~10s, but assuming the average power generation is 1kw, it is approximately
30,000 floating bodies are required. Each floating body has a difference in tension when the floating body rises and descends (the tension is large when rising...
Floating body has a large submersion depth (e.g. submergence depth of 1.2m, tension
2.7t), and the tension is small when descending...the amount of seawater removed by the floating body (e.g. ^1.3m3 ) to create a small submergence depth (e.g. submersion depth 0.8m, tension 1.4t) lowers the wave level. They must be installed at sufficient intervals to prevent significant changes and to prevent individual floating bodies from colliding, and should be installed at intervals of approximately 10m x 10m.
In this case, a typical installation would be approximately 1 km from the coastline, with a width of 5 km and a depth of 5 km.
They were installed at a distance of 320 m (500 pieces x 32 rows = 16,000 pieces), and another group was installed offshore, 10 to 20 km apart.
A total of 32,000 pieces will be installed. Approximately 40% of the wave energy is absorbed by the 32 rows of floating bodies. The reason for establishing a gap of 10 to 20 km between the first group offshore and the second group closer to the coast is to take advantage of the action of absorbing wind energy and regenerating waves on the sea surface between them. . In this way, when constructing a large-scale utility-scale power plant, it is necessary to occupy a vast area of sea surface, and the water depth is 20 to 150 meters on the average coast, so it is necessary to install it in a place with great water depth. ,
In a structure in which the piston rod is attached directly to the floating body, it is inconvenient to manufacture a very long rod by connecting a large number of long and thin rods, and there are also restrictions such as the inability to wind it up and disadvantages such as increased weight. Therefore, it is preferable that the piston of the drainage pump is connected to the floating body by a cable. However, as described above, the conventional method of mooring a floating body using cables has the problem of not being able to increase wave energy utilization efficiency, and the problem of low durability of the floating body and cable against waves.

Therefore, the purpose of the first invention of the present application is to
It is suitable for installation submerged in relatively deep water locations, and the floating body mooring cable is always maintained under tension due to the differential pressure within the piston-cylinder device that makes up the pump, which improves wave energy utilization efficiency. An object of the present invention is to provide a floating body type wave power generation device that can improve the wave resistance of the floating body and the cable.

In addition to the above-mentioned object, the second object of the present invention is to provide a wave power generation device that can be constructed as an underwater power generation base where workers can enter the inside of the pressure housing structure and carry out maintenance, inspection, maintenance, etc. It is to be.

A feature of the present invention is that a piston cylinder device functioning as a pump is connected to a cable for mooring a floating body, and the piston cylinder device is provided with a pump chamber and a low pressure chamber with a piston in between. The inlet of is connected to an intermediate pressure tank so that the intermediate pressure tank provides a head pressure, and the low pressure chamber is connected to a low pressure tank that provides a head pressure lower than the head pressure of the intermediate pressure tank to act on the piston. The purpose is to hold the cable under tension by means of a pressure difference.
That is, the wave power generation device according to the first invention of the present application includes a piston-cylinder device whose one end is moored, a floating body connected to the piston of the piston-cylinder device via a cable, and the piston-cylinder device. a pump chamber formed above the piston and having a suction port and a discharge port; a low pressure chamber formed below the piston; and a pump chamber connected to the suction port of the pump chamber to apply head pressure to the suction port. a low pressure tank connected to the low pressure chamber and arranged to provide the low pressure chamber with a head pressure lower than the head pressure of the medium pressure tank;
The piston is constantly pulled downward by the difference in water head pressure provided by the medium pressure tank and the low pressure tank to hold the cable in tension, and the piston is configured to maintain the cable under tension. A discharge port of the chamber opens into the water, a water intake port of the power generator opens into the water, and a drain port is connected to the medium pressure tank. According to this configuration of the invention, the free water surface forms a source of high pressure, and the differential pressure between the head pressure due to this free water surface and the pressure of the intermediate pressure tank generates a water flow that operates the power generator. piston·
The pressure of the medium pressure tank acts on the pump chamber formed above the piston of the cylinder device even in the lowered position of the floating body, and the pressure of the low pressure tank acts on the low pressure chamber below the piston, so the piston is always downward due to the differential pressure. The cable is maintained under tension. Therefore, most of the vertical movement of the floating body due to the vertical movement of the waves can be transmitted to the piston-cylinder device, and the efficiency of using wave energy is greatly increased. Furthermore, the differential pressure within the piston-cylinder device is, for example, 50 atmospheres or more, similar to a so-called hydraulic device.
Since it can be set to a desired size of about 100 atmospheres, the floating body can be restrained with a cable tension as large as several times to more than 10 times the mass of the floating body. Therefore, the floating body is strongly restrained to a weight on the seabed by a cable that is always linearly taut, so it follows the violent movement of waves well and the cable does not come loose. For this reason, it is less exposed to wave impact and its wave resistance is improved. Furthermore, this configuration of the present invention is suitable for installation at a relatively deep location relatively far from the coast, and is convenient for implementation as a large-scale underwater power generation base. In carrying out the present invention, the intermediate pressure tank and the low pressure tank can each be constituted by a water tank pressurized to a predetermined pressure.

Further, a second invention of the present application provides a piston/cylinder device whose one end is moored, a floating body connected to the piston of the piston/cylinder device via a cable, and a floating body above the piston within the piston/cylinder device. a pump chamber formed in the pump chamber and having an inlet and a discharge port, a low pressure chamber formed below the piston, and an intermediate pressure chamber connected to the inlet of the pump chamber and arranged to apply a head pressure to the inlet. a tank, a low-pressure tank connected to the low-pressure chamber and arranged so as to give the low-pressure chamber a head pressure lower than the head pressure of the medium-pressure tank, and a water turbine generator, and the piston is connected to the medium-pressure tank. The cable is constantly pulled downward by the difference in head pressure given by the pump chamber and the low-pressure tank, and the cable is kept under tension. The intake opens into the water,
The outlet is connected to the medium pressure tank, and the power generation device and the low pressure tank are housed in a pressure housing, and the pressure housing includes a valve extending upward from the pressure housing and protruding above the water surface from the top into the pressure housing. It is a wave power generation device provided with a tower structure with means of access. According to this configuration, in addition to the above-mentioned advantages, it is possible to construct an underwater power generation base in which workers can enter and work. The device of the present invention is located relatively far from the coast, at a depth of 100 mm.
Particularly suitable for building power plants at distances of 300m to 300m.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, in FIG. The water intake is opened into the water by a water intake pipe 5 having a filter device 4. Floating body 6 arranged to float on the water surface
The cable 7 connects the piston/cylinder device 8
The piston-cylinder device 8 includes a cylinder 10 whose one end is connected to a weight 9, and a piston 11 that reciprocates within the cylinder 10. A piston rod 11a of the piston 11 is connected to the cable 7. be done. In the cylinder 10, a pump chamber 12 is formed above the piston 11, and a low pressure chamber 13 is formed below the piston 11.

The pump chamber 12 is provided with a discharge port 14 having a check valve that opens only on the discharge side and a suction port 15 having a check valve that opens only on the suction side. The port 15 is connected to the generator 3 through a pipe 16.
connected to the drain. A tower structure 17 extending upward and protruding above the water surface is formed in the pressure housing structure 1, and within this tower structure 17,
In addition to the elevator 18 for raising and lowering the housing structure 1, an intermediate pressure tank 19 is formed in the middle thereof. The lower part of the intermediate pressure tank 19 is connected to the pipe 16 from the outlet of the generator 3, and the upper part is opened to the atmosphere by a ventilation pipe 20 passing inside the tower structure 17, and its water level is equal to or lower than the suction of the pump room 12. Mouth 15
Determine the head pressure applied to A low pressure tank 21 is installed in the pressure housing structure 1, and the bottom of the low pressure tank 21 is connected to the cylinder 1 by a low pressure pipe 25.
The upper part of the low-pressure chamber 13 inside 0 is open to the atmosphere via a ventilation pipe 20. In the low pressure chamber 13, water leaks from the pump chamber 12 through the piston 11, and this water enters the low pressure tank 21. In order to maintain the water level in the tank within a certain range, the water leakage pump 22 is activated. provided.

The water head pressure due to the free water surface is applied to the water intake of the generator 3, and the water head pressure due to the water level in the medium pressure tank 19 is applied to the water outlet, and the generator 3 generates a water flow generated by the pressure difference. Operate. Medium pressure tank 19
The water level within is maintained by drainage based on the pumping action of the piston-cylinder device. piston·
The pump action of the cylinder device is based on wave energy, and it is conceivable that the water level in the medium pressure tank 19 will fluctuate due to fluctuations in wave energy. A control valve 23a is provided, a water intake pipe 5 and a drain pipe 1 are installed.
6 and an overflow pipe 24 having a valve 23b may be provided. That is, normally the valve 23b is closed,
Valve 23a is open. If the amount of water discharged by the piston-cylinder device fluctuates and decreases, the opening degree of the valve 23a is controlled to adjust the amount of suction, and the balance of suction and discharge is maintained so that the pressure in the intermediate pressure tank remains constant. . On the other hand, if the amount of drainage increases and exceeds the capacity of the generator, the valve 23a remains fully open and the opening of the valve 23b is controlled to adjust the overflow amount and maintain the balance between suction and discharge. Make sure that the pressure in the medium pressure tank remains constant. Pump room 1
The head pressure due to the water level in the intermediate pressure tank 19 acts on the chamber 2, and the head pressure due to the lower water level in the low pressure tank 21 acts on the low pressure chamber 13, so the piston 11 moves downward due to the differential pressure. is pressed, holding the cable 7 under tension. The tension force on the cable 7 may be applied to such an extent that about 1/3 of the floating body 6 sinks when the waves descend, and about 2/3 sinks when the waves rise.
Inside the pressure housing structure 1, various facilities can be provided to allow personnel to work safely inside.

FIG. 2 is a perspective view showing the external appearance of the power generator shown in FIG. 1, in which two tower structures 17 are installed in the pressure housing structure 1, and a discharge pipe 16 and a A low pressure pipe 25 extends out. The drain pipe 16 is in the form of a collector pipe, and drain branch pipes 16a extend from the drain pipe 16 on both sides at regular intervals in the length direction, and each drain branch pipe 1
Connecting pipes 16b to the pump chamber 12 of the piston-cylinder device 8 are provided at regular intervals in the longitudinal direction of the piston 6a. Assuming that the number and capacity of the piston-cylinder devices connected to each drain branch pipe 16a are the same, the flow rate in the drain pipe 16 will decrease at a constant rate along its length. . When designing such a pipe, it is most preferable from a material economic standpoint to vary the pipe diameter so that the ratio of the diameter of the maximum flow part to the diameter of the minimum flow part is approximately 10:4. . The pipe diameter may be changed continuously or in steps. Similarly, branch pipes 25a are provided in the low pressure pipe 25 at predetermined intervals in the length direction, and each branch pipe 25a is connected to the low pressure chamber 13 of the piston/cylinder device 8 at regular intervals in the length direction. 25b is provided.

FIG. 3 shows another embodiment of the present invention,
The pressure housing structure 1 is a submerged floating frame structure 30
The upper part of the tower structure 17 is provided with a living room 31 for the workers. This living room 31 also functions as a floating body in case of an emergency. Also,
Some of the components of the floating frame structure 30 can also be used internally as drain pipes and low pressure pipes.

FIG. 4 shows yet another embodiment of the invention, in which a medium pressure tank 32 is placed on the floor 2 in the pressure housing structure 1 and is brought to a predetermined pressure with compressed gas. It has a pressurized tank structure. The bottom of the medium pressure tank 32 is connected on the one hand to the drain pipe 16 of the generator 3 and on the other hand by a pipe 33 to the pump chamber 12 of the piston-cylinder arrangement 8.
It is connected to the inlet 15 of. Low pressure tank 21
The tank structure is also pressurized to a lower pressure than the intermediate pressure tank 32. In some cases, the low pressure tank 21
may be of the open type, similar to the example shown in FIG.

As described above, the device of the present invention maintains the cable in tension by applying differential pressure to the piston of the piston-cylinder type pump device connected to the floating body by the cable, so when in use, the device maintains the cable in tension. There is no need to worry about breakdowns, and wave energy can be extracted effectively. Furthermore, the device of the present invention can be installed at a relatively deep location, relatively far from the coast, and can be operated safely.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a submarine power generation device showing one embodiment of the present invention, Fig. 2 is a perspective view of its external appearance, Fig. 3 is an external perspective view showing another embodiment, and Fig. 4 is another embodiment. A sectional view similar to FIG. 1 showing an example, and FIGS. 5a and 5b illustrate the operation of the conventional device. 1...Pressure housing structure, 3... Generator, 6
... Floating body, 7 ... Cable, 8 ... Piston cylinder device, 12 ... Pump room, 13 ... Low pressure room, 17 ... Tower structure, 19 ... Medium pressure tank,
21...Low pressure tank.

Claims (1)

[Scope of Claims] 1. A piston and cylinder device whose one end is moored, a floating body connected to the piston of the piston and cylinder device via a cable, and a suction body formed above the piston in the piston and cylinder device. a pump chamber having an inlet and a discharge outlet, a low pressure chamber formed below the piston, and an intermediate pressure tank connected to an inlet of the pump chamber and arranged to apply head pressure to the inlet; A cable connected to the low pressure chamber, applying a head pressure lower than the head pressure of the medium pressure tank to the low pressure chamber, and constantly pulling the piston downward by the difference in the head pressures provided by the medium pressure tank and the low pressure tank. It consists of a low-pressure tank arranged to maintain the water under tension, and a water turbine generator, the discharge port of the pump chamber opening into water, and the water intake of the generator having a water head pressure of the medium-pressure tank. A wave power generation device that opens into the water at a position where higher head pressure is applied, and has a drain port connected to the medium pressure tank. 2. In the wave power generation device according to claim 1, the intermediate pressure tank is a tank arranged above the pump chamber and whose upper part is open to the atmosphere,
The wave power generation device includes a tank in which the low pressure tank is located below the medium pressure tank and whose upper part is open to the atmosphere. 3. In the wave power generation device according to claim 1, the medium pressure tank has a water head pressure lower than that of the water intake port of the power generation device, and the low pressure tank has a water head lower than the water head pressure of the medium pressure tank. A wave power generator consisting of tanks each pressurized by compressed gas. 4. A piston/cylinder device with one end moored, a floating body connected to the piston of the piston/cylinder device via a cable, and a floating body formed above the piston within the piston/cylinder device with an inlet and a discharge port. a pump chamber having a pump chamber, a low pressure chamber formed below the piston, an intermediate pressure tank connected to the suction port of the pump chamber and arranged to apply a head pressure to the suction port, and a medium pressure tank connected to the low pressure chamber. A head pressure lower than the head pressure of the intermediate pressure tank is applied to the low pressure chamber, and the piston is constantly pulled downward to maintain the cable in a tensioned state due to the difference in head pressure provided by the intermediate pressure tank and the low pressure tank. It consists of a low-pressure tank arranged as shown in FIG. The power generator and the low pressure tank are housed in a pressure housing, and the pressure housing has a drain port connected to the medium pressure tank, and the pressure housing has a drain opening extending above the water surface and extending upward from the pressure housing. A wave power generation device provided with a tower structure having means for entering and exiting into the pressure housing from a projecting top. 5. The wave power generation device according to claim 4, wherein the pressure-resistant housing is installed at the bottom of the water. 6. The wave power generation device according to claim 4 or 5, wherein the intermediate pressure tank is provided in the middle of the tower structure, surrounding the outer periphery of the tower structure.