FR2461194A1 - Tidal energy type submarine constant pressure gas collector - has anchors for tank with water passage and gas intake and outlet - Google Patents

Abstract

Compressed gas, esp. air under high pressure, is given off under constant pressure by an appliance for collecting such gas, under water as in exploitation of energy from tides or other currents in the sea. Use is made of a tank fitted under the water, for gas storage, with one or more openings for water to flow in and out. An intake and an outlet opening are in connection with the tank, to convey compressed gas in and out of it. It has fittings for anchoring under water, pref. a series of weights and connecting wires. It can contain a winch, with chain wheel and chain, with a weight connected to the chain and provision for activating the winch when the water column changes.

Description

 The present invention relates to a device for accumulating a compressed or pressurized gas, such as compressed air, under water so that it can then deliver this gas under constant pressure.

 In an attempt to use the energy of ocean currents and the tide, the Applicant has invented a transducer (see US Patent No. 071,305 of January 31, 1978) which includes a mechanism for producing compressed air in response to the rotation of 'a turbine driven by these currents, this compressed air can be used to rotate an electric generator. One of the difficulties encountered in the use of such transducers is that, at changes of direction or of flow of sea currents, the rotation of the turbine is momentarily stopped or slowed down, so that the air supply Generator compressed stops or fluctuates. One solution to this problem would be to store compressed air in an accumulator installed on land, from where it could be drawn when the turbine is in abnormal operation. However, conventional accumulators are unable to produce compressed air at a constant pressure because this pressure is a function of the amount of air that remains in the accumulator. In addition, the accumulators must have a sufficiently robust structure to withstand the pneumatic pressure which develops within them and therefore their manufacture is relatively complicated and expensive.

 -According to the present invention, such an accumulator comprises a reservoir adapted to be placed underwater and having an opening, as well as an inlet conduit and an outlet conduit connected to the reservoir to allow the introduction and the evacuation of the pressurized gas into and out of it, this gas being permanently maintained under constant pressure due to the water column present at the level of the tank. The tank is anchored by means of weights or is kept in suspension underwater using floats whose position is adjustable so as to maintain the tank at a practically constant depth. The tank could be movable relative to the weights so that it can move vertically to compensate for variations in the water column.

 Consequently, the subject of the present invention is an accumulator for supplying gas at a constant pressure regardless of the quantity of gas remaining therein.

 Another object of the invention is to provide an accumulator intended to be installed underwater, the structure of which is simple and robust, which is light and which can be put in place easily.

Other characteristics and advantages of the invention will emerge from the description which follows, given solely by way of nonlimiting example, with reference to the appended drawings in which
- Figure 1 is a perspective view, with cutaway, of an accumulator constructed in accordance with a first embodiment of the invention
- Figure 2 is an enlarged sectional view taken along the line
II-II of Figure 1, showing a transducer forming part of an energy transformation assembly;
- Figure 3 is a perspective view, with cutaway, of an accumulator according to a second embodiment of the invention
- Figure 4 is a perspective view, with cutaway, of a modified float which can be incorporated in the accumulator of Figure 3
- Figure 5 is a perspective view of an accumulator assembly according to a third embodiment of the invention
- Figure 6 is an enlarged perspective view, broken away, of an accumulator used in the assembly of Figure 5
- Figure 7 is a sectional view taken along the line VII-VII of Figure 6; and
- Figure 8 is a perspective view of an accumulator assembly according to a fifth embodiment of the invention.

 The present invention is particularly well suited for being incorporated in an accumulator such as that shown schematically in FIG. 1 where it is designated as a whole by the reference 10.

 In this figure, we see a transducer assembly group 11 comprising a certain number of elementary transducers 12 intended to convert the energy of the sea currents or the tide into energy contained in a high pressure fluid, such as a compressed gas. , this fluid being directed by a conduit 13 towards the accumulator 10 which supplies it to a power station 14 installed on the ground.

 The transducer assembly 11 is normally submerged and is anchored to the bottom of the sea. As can clearly be seen in FIG. 2, each transducer 12 comprises a rectangular envelope 15 which encloses a compensation chamber 16 in which a pneumatic pressure is maintained equal to the water column corresponding to the depth at which the transducer 12 is installed; a water circulation channel 17 open at its two ends 18 extends under the compensation chamber 16, and a turbine 19 with radial blades 20, the upper part of which extends into the compensation chamber 16 and the part of which lower constantly plunges into the water of the channel 17, is mounted inside the casing 15, the turbine shaft 19 being connected to an energy transformation mechanism 21 such as an air compressor. Two air traps 22, open downwards in the direction of the water circulation channel 17, are arranged on either side of the compensation chamber 16 to collect the air which could be escaped from it in the channel 17 when the transducer assembly 11 is tossed, for example when the sea is rough. The air collected by the chambers 22 can be reintroduced into the compensation chamber 16 by two pipes 23 provided with valves. Near the open ends 18 of the channel 17, two guides 24 are mounted on the transducer 12 to direct the water currents entering the channel 17.

 The power station 14 contains one or more electric generators (not shown) which use the compressed air supplied by the accumulator 10 as a working fluid to produce electricity, the power station 14 can be installed on a boat or anchored to the bottom from the sea, as appropriate.

The accumulator 10 comprises a reservoir 25 having the shape of a hollow cylinder made of a rigid material, such as for example a plastic material or a stainless steel, the upper end of this reservoir being closed by a circular wall 26. The side wall 27 of the reservoir 25 has a number of openings 28 located near its lower end and circumferentially spaced from one another, water being able to enter and leave the reservoir 25 through these openings 28. inlet 29 and an outlet conduit 30 open into the reservoir 25 by passing through the upper wall 26 thereof, the inlet conduit 29 being connected to the conduit 13 coming from the transducer assembly 11 to supply the reservoir 25 with gas under pressure, while the outlet conduit 30 is connected to the power station 14 in order to direct the compressed gas leaving the reservoir 25 towards the latter.

 The reservoir 25 is anchored to the bottom of the sea by a number of weights 31 each of which is connected to the reservoir 25 by a cable 32. The accumulator 10 also includes two vertical pipes 33 mounted on the reservoir 25 at two diametrically opposite points, the lower end 34 of each pipe 33 opening into the tank 25, while its upper end 35 opens underwater, near the upper wall 26 of the tank 25. The pipes 33 also allow water to enter and get out of the tank 25.

The operation of the accumulator 10 which has just been described is as follows
The compressed air produced in the transducer assembly 11 is directed through the conduits 13 and 29 inside the reservoir 25 of the accumulator. The continuous introduction of air into the tank 25 has the effect of pumping the water contained therein through openings 28 and pipes 33 to the surrounding body of water, so that the water level decreases in the reservoir 25. When the compressed air contained in the reservoir 25 is directed through the outlet conduit 30 to the power station 14, a certain amount of water enters through the openings 28 and the pipes 33 in the reservoir 25 and from this fact, the water level rises in the latter. In other words, the air contained in the reservoir 25 is always maintained at a pressure equal to the water column corresponding to the depth at which the accumulator 10 is submerged. Thus, for example, assuming that the accumulator 10 is at a depth of 50 m, the water column at such a depth is approximately equivalent to a pressure of 6 kg / cm (absolute pressure). Consequently, the pneumatic pressure remains constant in the reservoir 25 and the compressed air, which is supplied by the reservoir 25, is at a pressure sufficiently stable to be able to serve as a source of energy for the generation of electricity. Since the pressure of the air contained in the tank 25 is equivalent to the water column corresponding to the depth at which the aerator 10 is installed, it is quite obvious that the pressures acting on the interior and exterior surfaces of the upper wall 26 and of the side wall 27 of the reservoir 25 are equalized, so that the reservoir 25 is not subjected to any deformation and is not liable to be broken by excessive forces which could otherwise be exerted on him due to the presence of compressed air. The accumulator 10 thus constructed is particularly well suited for maritime areas where the sea level varies only slightly.

 FIG. 3 illustrates an accumulator 36 according to a second embodiment of the invention, which is adapted to be installed on the bottom of the sea.

The accumulator 36 is adapted to be used in regions where the sea level varies considerably, under the effect of the tides, for example. The accumulator 36 comprises a cylindrical tank 37 having an open bottom 38 through which the sea water enters and leaves. An inlet pipe 39 and an outlet pipe 40 allow the compressed air to pass from the transducer assembly 11 into the tank 37 and from the tank 37 to the power station 14.

A number of weights 41 are suspended from the base of the tank 37 to keep the tank vertical in the water. The reservoir 37 comprises means for being maintained at a practically constant depth in the water, these means comprising a winch 42, mounted on the upper wall 43 of the reservoir 37 and comprising a pulley 44 associated with a number of wedges 45 having a ends fixed to the pulley 44 so as to be able to be wound and unwound therefrom when the winch 42 is actuated; a number of hollow floats 46 are further connected to the other ends of the cables 45. The floats 46 are made of an expandable material such as rubber or synthetic resin and are filled with air under a predetermined pressure. level detectors 47 of known type are mounted on the internal surface of the cylindrical wall 48 of the tank 37, these detectors 47 being designed to control the operation of the winch 42 when the water reaches a predetermined level in the tank 37.

When the quantity of compressed air contained in the reservoir 37 increases as a result of the continuous inflow of air through the inlet duct 39, the reservoir 37 is liable to rise due to the increase in its buoyancy. At the same time, the water level drops in the tank 37 and it can arrive at a predetermined lower point where the detectors 47 start the winch 42 to wind the cables 45 so as to lower the floats 46 to the sketched position 49. When the floats 46 descend, they shrink and their buoyancy decreases, which has the consequence of reducing the total buoyancy of the accumulator 36 thereby suppressing its tendency to rise. On the other hand, during the continuation of the evacuation of the compressed air through the outlet conduit 40, the water level rises in the reservoir 37 until reaching a predetermined upper point from which the detectors 47 come into action and start the winch 42 which rotates the pulley 44 in the opposite direction. Therefore, the cables 42 are unwound and the floats 46 can go back to the position represented by the broken lines 50. By raising, the floats 46 are inflated and develop additional buoyancy which compensates for the reduction in buoyancy of the tank resulting from the compressed air consumption.

It can therefore be seen that the accumulator 36 is automatically maintained at a constant level, despite the variations in the level of the water in the reservoir 37.

 FIG. 4 represents a modified float 51 made of a rigid material such as plastic or steel, the float 51 having the shape of a hollow sphere which can be connected to the reservoir 37 of FIG. 3 by a chain 52. The float 51 is pierced with a certain number of holes 53 arranged in a circle around a hook 54 to which the chain 52 is fixed, and through which water can enter and leave the float 51. When it is used, the float 51 contains a predetermined quantity of air which, when the float is lowered, is compressed by reducing the buoyancy of the latter and when the float rises, relaxes by increasing its degree of buoyancy.

The float 51 is advantageous because it can withstand relatively large water pressures, does not risk breaking due to fatigue and therefore has a long service life.

 In a third embodiment, shown in FIGS. 5 to 7, a generator 55 submerged in the sea receives compressed air from the transducer assembly 11 via an inlet conduit 56 and generates electricity which is transmitted by power lines 57 to a substation 58 installed on land. The generator 55 essentially comprises an envelope 59, two accumulators 60 mounted in the envelope 59, intended for the storage of the compressed air arriving through the conduit 56, and a certain number of units 61 able to transform the energy of the compressed air contained in the accumulators 60 in electricity, units being of a known type. The assembly 55 is anchored to the bottom of the sea by a number of weights 62 attached to cables 63 in each of which is inserted a float 64. As can be clearly seen in FIGS. 6 and 7, each accumulator 60 comprises a reservoir cylindrical 65 which can move vertically in a sleeve 66 mounted in the casing 59, by means of a number of rollers 67 fixed on the cylindrical wall 98 of the reservoir 65 so as to be applied against the sleeve 66. The tank 65 comprises two compartments 68 and 69 disposed respectively at its upper end and at its lower end, the compartments 68 and 69 communicating with each other by pipes 70 each of which contains a valve 71. The compartments 68 and 69 are reinforced by a number of ribs 72.

 The bottom of the tank 65 is pierced with an opening 73 through which pass an air inlet duct 74 and an air outlet duct 75 which open inside the tank 65, the open ends of the ducts 74, 75 being located near the upper compartment 68. A winch 76 is mounted on the upper compartment 68 and comprises a toothed wheel 77 around which extends a chain 78 having a free end 79 and the other end 80 of which is connected to a weight 81 via a float 82, (Figure 5).

In FIG. 5, it can be seen that the air duct 56 is connected to the inlet ducts 74, while the outlet ducts 75 are connected to the units 61 of the generator. The generator 55 includes an air chamber 83, the upper part of which gives it a suitable degree of buoyancy so as to stabilize its position. From the generator 55, a conduit 84 is removed to evacuate the air consumed coming from the units 61.

 A pressure sensor 85 of any known type is provided in the tank 65 in order to transmit, when the water column varies, signals activating the winch 76.

 The energy of the sea and the tide is converted by the transducer assembly 11, into compressed air which is directed by the conduits 56 and 74 to the accumulators 60 where it is temporarily stored. The air is permanently maintained under constant pressure by the water column acting through the openings 73 of the tanks 65. The compressed air is then supplied by the conduits 75 to the units 61 of the generator which produce electricity.

When the sea level drops as a result of the ebb of the tide, the column of water acting on the accumulators 60 decreases and consequently the pneumatic pressure decreases in the tanks 65. At this moment, the detector 85 perceives this reduction in the water column and actuator winch 76 to rotate it in the winding direction of chain 78 with the result that the tank 65 descends, this resulting in an increase in the air pressure therein. When the level of l water is removed as a result of the rising tide, the air pressure increases in the tank 65 under the effect of the increase in the water column and this variation of the water column is noted by the detector 85 which then actuates the winch 76 in the opposite direction to unwind the chain 78. It can therefore be seen that the reservoir 65 is removed to reduce the pressure of the air it contains. This makes it possible to supply the generator units 61 with compressed air at a constant pressure.

 The compressed air which could be escaped through the opening 73 when the assembly 55 is tossed through a rough sea, is collected in the lower compartment 69 from which it is returned to the upper compartment 68 by the valve hoses 70.

 FIG. 8 represents a fifth embodiment of the invention in which the same references designate the same components shown in the preceding figures. An important part of this fifth embodiment resides in the presence of a partition 101 which floats on the surface of the water contained in the tank 60 to serve as an element of etaneheite and which is arranged so as to be able to move vertically following the vertical movements of the water in the tank. In the figure, there is indicated at 74 an inlet pipe for a gas under pressure and at 75 an outlet pipe.

Note that the upper ends of the inlet and outlet conduits 74 and 75 rise up to the upper part of the tank 60. The references 104 and 105 designate a second inlet conduit and a second outlet conduit which are detachably fixed in the inlet 74a and outlet 75a conduits, so that the gas can be extracted without being obstructed by the vertical movements of the reservoir 60.

 The fifth embodiment of the invention has the structure described above and thus, even when using a water-soluble gas, for example, such as ammonia or hydrogen chloride, this gas can be stores or accumulates without coming directly into contact with seawater thanks to the partition 102, which makes it possible to avoid losses of gas by dissolution.

We see in Figure 8 that the tank can be provided with a dehumidifier 111 at its upper part, if necessary. The presence of such a dehumidifier contributes to preventing droplets of water from forming in the tank 60, even when the pressurized gas feeds an accumulator installed at a great depth where the temperature is low and a device for removing humidity. is not inserted in the piping.

 In addition, the partition 101 may be hollow. In this case, to equalize the air pressure, the partition 101 can be provided, on its upper face, with a certain number of vents 113 each of which has a slightly projecting end. Thanks to the presence of these projecting ends, the water does not risk accumulating in the hollow partition 101, even when water droplets are created in the tank.

 It goes without saying that numerous modifications can be made to the embodiments shown and described without thereby departing from the scope of the invention.

Claims (14)

1. Device for accumulating a compressed gas under water, characterized in that it comprises  (A) a tank adapted to be placed under water to store the compressed gas, this tank comprising an opening through which water can enter and leave in and out of it  (b) an inlet conduit and an outlet conduit communicating with the reservoir for the introduction and evacuation of the compressed gas into and out of the reservoir; and  (c) means for anchoring the tank under water. 2. Device according to claim 1, characterized in that the anchoring means comprise a number of weights and a number of targets having one end connected to the weights and the other to the tank.  3. Device according to claim 1, characterized in that the anchoring means comprise a winch mounted on the tank and comprising a toothed wheel, a chain extending around this wheel so as to be driven by the latter when the winch is activated; a weight connected to the chain; and means provided on the tank for actuating the winch when the height of the water column varies in the latter.  4. Device according to claim 3, characterized in that it comprises an envelope adapted to beech anchored under water and a sleeve mounted in the envelope, the reservoir being supported in movement in the sleeve.  5. Device according to claim 4 characterized in that it comprises a number of rollers rotatably mounted on the tank and which are held in rolling contact against the sleeve.  6. Device according to claim 1, characterized in that said inlet and outlet conduits pass through said opening.  7. Device for accumulating a compressed gas under water, characterized in that it comprises  (A) a tank adapted to be placed under water to store the compressed gas, this tank having an opening through which water can enter and leave  (b) an inlet conduit and an outlet conduit communicating with the reservoir for the introduction and evacuation of the compressed gas into and out of it; and  (c) means provided on the tank to maintain it at a constant depth underwater.  8. Device according to claim 7, characterized in that said means comprise a winch mounted on the tank and comprising a pulley a number of cables, one of the ends of which is connected to the pulley so as to be wound around it. ci and be unrolled when the winch is in operation; a number of hollow floats connected to the other end of the cables; and means provided on the reservoir for actuating the winch when the water reaches a predetermined level in the reservoir.  9. Device according to claim 8, characterized in that the hollow floats are inflatable.  10. Device according to claim 8, characterized in that each hollow float has a rigid wall pierced with a hole. 11. Device for accumulating a compressed gas under water, characterized in that it comprises  (a) a tank adapted to be placed under water to store the compressed gas, this tank having an opening through which water can enter and leave  (b) an inlet pipe and an outlet pipe communicating with the tank for the introduction and evacuation of the compressed gas  (c) means provided on the tank to keep it underwater at a constant depth; and  (d) a partition placed on the surface of the water contained in the tank, this partition being able to move vertically following the vertical movements of the surface of the water so that the stored compressed air is prevented from coming into contact with the water and be dissolved by it.  12. Device according to claim 11, characterized in that said means comprise a winch mounted on the tank and, having a pulley is connected a number of cabals one of the ends of which / to the pulley so as to be wound and unwound around it when the winch is actuated a number of hollow floats connected to the other end of the cables; and means provided on the tank for actuating the winch when the water reaches a predetermined level in the tank.  13. Device according to claim 12, characterized in that the hollow floats are inflatable.  14. Device according to claim 12, characterized in that each of the hollow floats comprises a rigid wall pierced with a hole.