NO841311L - PROCEDURE FOR USING THE ENERGY IN SURFACE WAVES IN A WASHING MASS, EX. THE WAVES ON THE SURFACE OF A SEA AND EQUIPMENT FOR EXECUTION OF THE PROCEDURE - Google Patents

Abstract

In a method and in equipment for utilizing the energy in surface waves, the flexible pipe is used. (21 which are divided into sections where one-way valves (4ab - 4jk) form connections between these and open in the same direction, with each section divided into two chambers by means of a slack, flexible liquid-tight membrane (9), ie.1) a first chamber or air guns (7a - 7k) which are closed on all sides and are intended to contain a gas or a gas mixture, e.g. air, and 2) a second chamber or water chamber (8a - 8k) communicating with the preceding and following second chamber or water chamber (8a - 8k) through the one-way valves (4ab - 4jk). The air chambers (7a - 7k) act as pressure accumulators for collection of pressure energy when the section in question is lowered, while total energy is released during the subsequent upward movement by driving some of the liquid in the water chamber through the one-way valve (4ab - 4jk) on the downstream side. Thus a pumping effect is obtained which can be used to drive a turbine or the like. The air chambers (7a - 7k) further provide buoyancy to the flexible pipe, so that separate buoyancy means, such as previously used flexible surface floats, can be omitted. The flexible pipes (2) and / or the transverse walls (3ab - 3jk) can be made of cheap plastic material, e.g. fiberglass-reinforced plastic film, and at least a portion of the manufacturing process can be performed at or near the final site of application to further reduce costs.

Description

The present invention relates to a method for utilizing the energy in the surface waves on a liquid mass, e.g. the waves on the surface of an ocean and the method is of the kind where the wave movements are utilized to move one or more elongated flexible pipes which are divided into a number of sections by means of liquid-tight transverse walls with single-layer valves which are arranged to open in the same direction.

In known methods of this kind, the wave movements produce a potential energy and/or kinetic energy in a liquid - normally the same as in the surrounding liquid mass - which flows in the pipe or pipes and this energy can be transferred to one or a number of energy converting devices such as turbines and the like.

In British Published Patent Specification No. 2,024,957

a method of the kind mentioned here is described, where the method is based on the use of a number of flexible pipes which are carried by a flexible surface float and which are divided into sections, separated from each other by one-way valves. These pipes are designed to be stretched out or contracted due to the wave movements, each section acting as a bellows.

Then the amount of energy that is available per unit area is limited, an acceptable level of power output can only be achieved by using equipment that covers a significant area of the liquid surface in question. This naturally means that it should be possible to manufacture the equipment to be used at sufficiently low costs, so that the method can be carried out in an economically sensible manner.

With this as a background, it is the main purpose of the present invention to arrive at a method of the kind indicated above, where the necessary equipment can be produced at very low costs. This is achieved by practicing the method using pipes in which each section is divided into two chambers by means of a flexible liquid-tight membrane, i.e.

1) a first chamber or air chamber which is closed on all sides and which is intended to contain a gas or a

gas mixture e.g. air, and

2) a second chamber or water chamber that is connected to the preceding and the subsequent second chamber or water chamber through one of the one-way valves.

By proceeding in the manner described here, it is possible to omit separate buoyancy aids, e.g. the surface float described in the aforementioned British patent document No. 2,024,957, the gas, gas mixture or air contained in the first chamber or air chamber in each section will provide the necessary buoyancy. Furthermore, this gas, gas mixture or air will act as a pressure accumulator that collects pressure energy for movements downwards in the wave valleys, while this energy is released during movement upwards towards the wave crests by driving some of the liquid from the other chamber or the water chamber in the section that applies through the one-way valve on the downstream side into the second chamber or water chamber in the following section, regardless of whether the chambers or sections are elastically compliant as in the known pipes mentioned above or not.

The method according to the invention is preferably carried out using tubes in which each first chamber or air chamber extends from one transverse wall to the next. By proceeding in this way, the gas, gas mixture or air contained in the first chamber or the air chamber will help to keep the pipe or pipes stretched out, and for this reason it or these can be made of thin-walled - and therefore relatively cheap - material such as plastic wrap.

The present invention also relates to equipment for carrying out the method according to the invention and is of the kind that comprises one or more elongated flexible pipes which are divided into a number of sections, by means of liquid-tight cross walls with a one-way valve where the valves are intended for

to open in the same direction. According to the present invention, this equipment is characterized by the fact that each section is divided into two chambers by means of a flexible liquid-tight membrane, i.e.: 1) a first chamber or air chamber which is closed on all sides, and is intended to contain a gas or a

gas mixture e.g. air, and

2) a second chamber or water chamber which is connected to the preceding and then the following second chamber or water chamber through the one-way valves.

A preferred embodiment of this equipment is characterized by the fact that each flexible chamber extends from one transverse wall to the next. In such an embodiment, the gas, gas mixture or air contained in the first chamber or air chamber will help to keep the pipe or pipes taut, and for this reason it or these are made of thin-walled material such as plastic foil, which is relatively cheap and easy to work with.

The equipment according to the invention can of course be constructed in many different ways on the condition that the conditions stated above are satisfied with a view to achieving the desired effect. However, it is believed that significant savings can be achieved by allowing the elongated pipe(s) to consist of

a) channel-shaped upper and lower parts which are assembled along outwards and e.g. fibre-reinforced transverse flanges with

stiffening devices in the circumferential direction, e.g. in the form of a polarized fiber reinforcement and possibly stiffening ribs that allow bending of the pipe across,

b) a number of cross walls that carry valve flaps, which cross walls are attached in a liquid-tight manner to the upper part, possibly also to the lower part, in the space limited by these components and with a mutual distance in the longitudinal direction corresponding to the length of the

first and second chambers, and

c) a number of flexible membranes whose longitudinal sides are fixed between the transverse flanges of the upper and lower part and

where the transverse sides of the membranes are fixed on a

liquid-tight way to the cross walls, while

d) the transverse flanges of the upper and lower parts are fixed in a liquid-tight manner to each other and to the longitudinal edges

of the membranes, preferably in that the transverse flanges at the longitudinal edges placed between them and the possible longitudinal fiber reinforcement are stacked and connected to each other in a liquid-tight manner, e.g. by welding so that protruding transverse fins are formed.

It can be predicted that flexible pipes constructed in this way will be extremely cheap to produce from equally cheap materials, e.g. fiberglass-reinforced plastic film or the like and it is also aimed that at least part of the manufacturing process must be able to be carried out at or close to the final location where the equipment is to be used.

It is not of critical importance for the functioning of the equipment according to the invention whether the one-way valves open in the direction of propagation of the waves, or in the opposite direction. It is thus not necessary to use a return flow pipe to connect the ends of the flexible pipes which are farthest from the energy converting equipment to this, and for that reason it is advantageous to place one or a number of pipes on the surface of the liquid (the water ) in the form of one or more loops where the ends of these are placed close to each other, and are connected to the energy converting equipment, e.g. a turbine. These loops can have any desired shape, for example a ring shape or a hairpin shape and can be placed in such a way in relation to each other that they intersect or cross each other partially or completely.

The invention is characterized by the features reproduced in the claims, and will be explained in more detail below with reference to the drawings, where

fig. 1 is a sketch showing the principle of the invention in the form of a longitudinal section through a piece of an elongated flexible tube which forms part of the equipment according to the invention and which floats on a sea surface with waves,

fig. 2 shows an example of how the elongated flexible pipe can be constructed in practice, and

fig. 3 is a sketch showing an imaginary method for producing the pipe shown in fig. 2.

As regards fig. 2, it should first be emphasized that the ratio between wave height and wavelength as indicated by the waves in the figure is greatly exaggerated compared to the waves that normally occur on a sea surface, and the waves in the figure are also drawn in the form of sine waves, which is not always is the case in reality. It is assumed that the direction of propagation for the waves is as shown with the double arrow 1, i.e. either to the right or to the left in the drawing.

The elongated pipe according to the invention is in fig. 1 shown as a flexible tube with an outer wall 2. The space inside the tube is divided into sections denoted by a,b,c,...k, where each section is separated from the neighboring section by means of a transverse wall, where the wall between sections a and b is designated as 3 ab, between sections b and c as 3bc etc. In all transverse walls 3ab, 3bc, etc. there is an opening with a valve flap 4ab, 4bc etc. As you will see in fig. 1, all valve flaps 4ab-jk are designed to open for liquid flow from left to right in the drawing, and to close for liquid flow in the opposite direction. The reference number 5 indicates the air above the sea surface, and the reference number 6 indicates the water below this sea surface. The flexible pipe 2 thus floats on the sea surface and follows the wave movements as indicated in the drawing. Each section of the pipe 2 between two successive transverse walls 3a, 3bc etc. is divided into two chambers, i.e. first a water chamber 8a, 8b, etc. which is connected to the adjacent water chambers at the ends through one-way valves formed by the openings in the cross walls 3ab, 3bc, etc. and valve flaps 4ab, 4bc, etc, and secondly by a pressure-collecting air chamber 7a, 7b, etc., which is closed in relation to the surroundings and which in the embodiment shown is separated from the water chamber or the liquid chamber 8a, 8b, etc. by means of a soft, flexible and liquid-tight membrane 9.

If it is assumed that the direction of propagation for the waves is to the right in fig. 1, one can imagine that the situation in a certain pipe section changes from one moment to the next in such a way that the situation will first be as shown on the far right of fig. 1, i.e. in section k, a moment later as in section j, the moment after that as in section h, etc. towards the left of the drawing. One can thus imagine that the liquid from the water chamber 8k can flow through the one-way valve 4jk in the direction of flow for this valve, i.e. from right to left down into the adjacent water chamber 8j, further through the next one-way valve into the water chamber 8h, etc. point indicated here at the transition between the water chamber 8g and the water chamber 8f, the one-way valve in question, i.e. 4fg, will be closed due to the back pressure from the water chamber 8f which follows.

When liquid flows in the water chambers 8j, 8h and 8g, the air will

in the air chamber 7j, 7h and 7g will be compressed due to the fact that the liquid pressure increases with increasing depth and - as indicated in the figure - the compression of the air chambers will increase with increasing depth. The air chamber 7g will thus exhibit its smallest

volume and will maintain this volume when the waves have propagated so far that the air chamber takes the position corresponding to the position of the air chamber 7f because the one-way valve 4ef is also closed due to the pressure from the overlying liquid in the water chamber 8e and the air pressure from the connected air chamber 7e . The situation for the next sections c,b and a in order mainly corresponds to the situation for the sections k,j and h already described, i.e. that the liquid in the water chambers 8c,8b and 8a can to a certain extent flow through the one-way valves 4bc and 4ab , and the following one-way valve without reference number in a manner corresponding to what is described with reference to sections k, j and h. Because of this, there will be insufficient back pressure in section c to keep the one-way valve 4cd closed, and which as a result, the air in the air chamber 7d will be able to expand and drive some of the water in the water chamber 8d through the one-way valve 4cd into the water chamber 8c in the next section. From this point the process continues cyclically as described above.

From the above it appears that it will be possible to achieve that for each wave passage there is a net displacement of liquid mass in the liquid chambers to the left, corresponding to the volume change in the air chambers, i.e. mainly corresponding to the difference in volume between the air chamber 7g or 7f and the air chamber 7c . This is based on the assumption that the movement of the liquid takes place without any backward pressure occurring. If a backward pressure occurs at the outlet end of the tube 2, the volume of liquid transported for each wave passage will naturally be somewhat less, since the backward pressure will prevent the air chamber from expanding to the extent indicated above.

A corresponding pumping effect will also occur if the waves propagate in the opposite direction, since what is necessary for the pumping effect is the up and down movement of each individual section of the flexible tube 2. It is thus possible to bring the tubes side by side with the opening of their one-way valves in two mutually opposite directions, and to connect the pipes together at one end and to e.g. a turbine at the other end.

Fig. 2 shows an example of how the elongated flexible pipe could be constructed in practice. The tube shown is shaped as a ribbed tube 10, with two horizontal transversely projecting fins 11 extending horizontally from each side of the tube. The transverse fins 11 partly serve to reinforce the pipe against bending at the transverse direction, and they must partly contribute to transmitting the pipe's wave motion. On the upper side, the tube 10 comprises stiffening ribs 12 which extend in the circumferential direction and stiffen the tube against expansion and contraction, but without reducing the tube's flexibility. The pipe is divided into sections by means of inclined transverse walls 13 which also serve as valve seats for the valve flaps 4. The membranes 9 which separate the air chambers 7 from the water chambers 8 can, as indicated, be shaped like a bag or a sack. Fig. 3 shows how a pipe of the type shown in fig. 2 can be produced. As can be seen from the lower part of fig. 3, the pipe consists of an upper part 14 and a lower part 15. The upper part 14 is shaped like an inverted channel and has transverse flanges 11, 11' which protrude from both transverse edges. In a similar way, the lower part 15 is shaped as a channel with transverse flanges 11, 11' at both edges. As indicated in fig. 3, the combined cross wall and valve seat 13 and the associated valve flap 4 have a simple curvature in the same direction and can be produced, e.g. when molding plastic or synthetic rubber. The components, which are shown in fig. 3, can be assembled by first gluing the transverse wall 13 together with the valve flap 4 in an inclined position in the upper part 14, after which the membrane 9 is placed against the undersides of the transverse flanges 11'. Next, the lower part 15 with its transverse flanges 11'<1> is placed against the underside of the parts of the membrane 9 which are in contact with the undersides of the transverse flanges 11-' on the upper part 14, after which these three components are joined together, e.g. . when welding. The transverse wall 13 can be omitted, and the upper part of the valve flap 4 is used as a transverse wall, while the lower part of the valve flap 4 is allowed to close against the lower part 15 of the pipe. When the transverse flanges 11', 11'' are assembled or are welded together with the transverse areas of the membranes 9, a pair of side fins will be formed, see the side fins 11 in fig. 2. In this connection, it should be pointed out that the width of the membranes 9 should be sufficiently greater than the width of the upper and lower part measured across the transverse fins or flanges to enable the membranes 9 to hang relatively loosely or loosely between the air chambers 7 and the liquid chambers 8, as the membranes would otherwise be partly exposed to a great stress due to the water pressure and partly counteract the compression of the air in the air chambers.

It should also be pointed out that most of the piped components can be made from a material with a very small wall thickness, because the internal excess pressure will keep the pipe stretched out. It is of course possible to use ordinary sea or ocean water as a liquid to utilize the wave energy in the liquid chambers, but this means that one must also accept some of the less fortunate properties of water of this kind, e.g. the content of pollutants, bacteria, algae, remains of seaweed and even live animals, such as fish, shrimp etc., which could render the equipment unusable after a certain time.

It is therefore advantageous if the elongated flexible pipes are connected to the energy converting equipment, e.g. turbines, in the form of one or more closed fluid circuits where the fluid may contain additives, e.g. funds for

a) reduction of hydraulic flow losses,

b) reduction of corrosion,

c) counteracting internal growth, e.g. of algae and/or bacteria,

d) lowering of the freezing point, and/or

e) signaling of leakage RF. e.g. in the form of non-toxic dyes, fluorescent dyes or an agent

which reacts with seawater and produces such a substance.

Claims (5)

1 m Method for utilizing the energy in surface waves in a liquid mass, e.g. the waves on the surface of an ocean, of the kind where the wave movements are utilized to move one or more elongated flexible pipes (2), which are divided into a number of sections (7a, 8a - 7k, 8k) by means of liquid-tight transverse walls (3ab- 3jk) with one-way valves (4ab - 4 jk). , which is intended to open in the same direction, characterized in that as the elongated flexible pipes, pipes are used in which each section is divided into two chambers by means of a flexible liquid-tight membrane (9), i.e. 1) a first chamber or air chamber (7a - 7k) which is closed on all sides and is intended to contain a gas or a gas mixture, e.g. air, and 2) a second chamber or water chamber (8a - 8k) which is connected to the preceding and then the following second chamber or water chamber (8a - 8k) through the one-way valves (4ab - 4jK). 2. Method as stated in claim 1, characterized in that flexible pipes are used where each first chamber or air chamber (7a - 7k) extends from one transverse wall (3ab - 3jk) to the next. 3. Equipment for carrying out the process specified in claim 1 or 2 and comprising one or more elongated flexible pipes (2) which are divided into a number of sections (7a, 8a - 71 - 8k) by means of liquid-tight transverse walls ( 3ab - 3jk) with non-return valves (4ab - 4jk) in the walls, designed to open in the same direction, characterized in that each section is divided into two chambers by means of a flexible fluid-tight membrane (9}, i.e. 1). a first chamber or air chamber (7a - 7k) which is closed on all sides and is intended to contain a gas or a gas mixture, e.g. air, and 2) a second chamber or water chamber (8a - 8k) which is connected to the preceding and then the following second chamber or water chamber (8a - 8k) through the check valves (4ab - 4jk). 4. Equipment as stated in claim 3, characterized in that each first chamber or air chamber (7a - 7k) extends from a transverse wall (3ab - 3jk] to the next. 5. Equipment as specified in claim 4, characterized in that the elongated pipe(s) consist of a) channel-shaped upper and lower parts (14, resp. 15) which are assembled along outwards e.g. fibre-reinforced transverse flanges (11', resp. 11''), with stiffening devices in the circumferential direction, i.e. in the form of a polarized fiber reinforcement and optionally: stiffening ribs (12) which allow transverse bending of the pipe, b) a number of cross walls (13) with valve flap is 4), which cross walls are attached in a liquid-tight manner to the upper part (14), possibly also to the lower part (15) in the space limited by these components and with a distance from each other in the longitudinal direction corresponding to the length of the first (7a - 7k) and second (8a - 8k) combs.,. and c) a number of flexible membranes (9), whose longitudinal edges are fixed between the transverse flanges (11', resp. 11'') on the upper (14) and lower (15) part, and whose transverse sides are fixed in a liquid-tight manner to the transverse walls (13), whereas d) the transverse flanges (11', resp. 11') on the upper and lower parts (14, 15) are fixed to each other in a liquid-tight manner and to the longitudinal edges of the membranes (9), preferably at the transverse flanges, with the longitudinal edges ..av_ .mem the branes lying between them and any longitudinal fiber reinforcement are stacked and joined in a liquid-tight manner, e.g. by welding, so that outwardly directed transverse fins (11) are formed.