WO2000019099A1

WO2000019099A1 - A device for moving a liquid or a gas

Info

Publication number: WO2000019099A1
Application number: PCT/SE1999/001706
Authority: WO
Inventors: Göran Engdahl; Ulf Olsson
Original assignee: Cetus Innovation AB
Current assignee: Cetus Innovation AB
Priority date: 1998-09-25
Filing date: 1999-09-27
Publication date: 2000-04-06
Anticipated expiration: 2001-03-25
Also published as: AU6380899A; EP1115978A1; SE9803264L; SE515323C2; SE9803264D0

Abstract

A device for moving a liquid or a gas, which includes a framework (1), at least one influencing member (2) intended for influencing said liquid or gas, and an arrangement for moving the influencing member in a movement in relation to the framework in order to bring liquid or gas from a first area, and to deliver liquid or gas to a second area, substantially separated from the first area.

Description

A DEVICE FOR MOVING A LIQUID OR A GAS

THE FIELD OF THE INVENTION AND PRIOR ART

The present invention refers to a device for moving a liquid or a gas.

The field of the invention comprises inter alia devices intended to be arranged completely below the water surface in order to generate pressure waves in the water by moving quantities of water, for instance for the technical fields of seismology and tomography.

By seismology is meant in the first place reflection seismology, which for instance is employed for detecting oils in the earth crust. In conventional seismology devices, pressure wave sources transmit pressure waves, which penetrate the earth crust, are reflected and received by hydrophone cables. Depending on the signal picture received, conclusions may be drawn regarding density differences in the earth crust and thus also about a possible existence of oil. Conventional pressure wave sources normally operate within a frequency range of 10-100 Hz.

The earth crust functions as a filter and damps pressure waves. Furthermore, the earth crust damps pressure waves of a higher frequency more than pressure waves of lower frequency, which means that pressure waves of a lower frequency penetrate deeper into the earth crust. In order to obtain an as good resolution as possible in the signals received, it is advantageous to utilise an as great band width as possible. To this end, it would be desirable to provide a device which enables generation of pressure waves of low frequencies.

It is known to generate pressure waves of low frequencies by means of devices based upon air cannons. Such air cannons rely on the fact that a high air pressure is built up in a chamber, whereafter the air at this high pressure is released in water, which involves an explosion-like course. A problem with air cannons, which per se give low frequencies down to about 5 Hz, is that they are difficult to handle due to the requirement of very large volumes at low frequencies, and that the explosion-like courses occur in a relatively uncontrolled manner.

In tomography, the sound velocity is measured in different sea areas, wherein it is possible to determine the temperature in these areas and thus it is also possible to draw conclusions about the global heating or the so-called "greenhouse effect". Tomography relies on the same technique as seismology, i.e. a source generates pressure waves and a receiver receives these waves, whereafter the signals received are analysed. Also in this case, it is a problem that present pressure wave sources are not capable of transmitting pressure waves of low frequencies, i.e. substantially lower than 10 Hz, at a high accuracy and high reliability.

The field of the invention also involves devices for moving a liquid or gas, which are intended, at least partly, to be in contact with the liquid or gas to be moved. Such devices normally are named pumps. Especially, it is referred to devices for providing relatively large flows, such as more than 1 m³/s.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a device for moving a liquid or gas, which overcomes the above mentioned disadvantages of conventional pressure wave sources for generating, during use as a pressure wave source, pressure waves of a relatively low frequency. A secondary object of the invention is to provide a device, which enables pumping of relatively large volumes of water per time unit.

These objects are obtained by the device according to the invention by the fact that the device includes a framework, at least one influencing member intended for influencing said liquid or gas, and an arrangement for moving the influencing member in a movement in relation to the framework in order to bring liquid or gas from a first area and to deliver liquid or gas to a second area, substantially separated from the first area. By providing the device below the water surface, a lower pressure than that of the surrounding water in said first area and a higher pressure than that of the surrounding water in said second area are obtained during said moving of the influencing member.

The device according to the invention is also well suited to be employed within further technical fields, for instance as an apparatus for propulsion of water carried crafts. Such applications will be described in detail below.

According to a preferred embodiment of the invention, the influencing member is arranged to be moved along a substantially straight path when it influences said liquid or gas. By a proper design of the device in other respects, this embodiment provides the conditions for the achievement of a substantially coherent flow. When the device is employed as a pressure wave source, the generation of pressure waves of a great range is enabled.

According to a further development of the invention, the moving arrangement includes at least one first flexible element and the influencing member is connected thereto. Furthermore, the flexible element runs over a first pair of guiding members, which are provided at a distance from each other on the framework. Thereby, a constructively simple moving arrangement is provided, which is efficient with regard to the costs. According to a further development, the influencing member is connected in an articulated manner to said flexible element. Hereby, conditions are created for the achievement of a durable device.

According to another preferred embodiment of the invention, the framework has an inner space delimited by a delimiting means and at least two openings leading to the space. At least one part of the moving movement of the influencing member extends in the space and the influencing member is arranged to form, during the movement of the latter, said first and second area, at a first and second of said openings, respectively. This means that said liquid or gas may be moved between the openings in the inner space without being substantially influenced by the conditions outside the framework.

According to a further development of the preceding embodiment, said influencing member has, in an active position during said part of the moving movement extending in said space, a substantially equally great effective area as an inner cross-sectional area of the space along said part. By the active position is meant herein the position, in which the influencing member is arranged when it is intended to move said liquid or gas. By effective area is meant a projection of the area of the influencing member on a plane perpendicular to the moving movement. Hereby, the influencing member prevents significantly said liquid or gas from by-passing the same in the inner space when it is arranged in the active position.

According to another preferred embodiment of the invention, the device includes means for supporting the influencing member during the movement in the space from a substantially opposite side of the space in relation to the edge of the influencing member, which is connected to the flexible element in order to maintain the influencing member in the active position during the movement in the space. Hereby, a stable maintaining of the influencing member in the active position is obtained, when it is moved through the inner space. This creates, in its turn, proper conditions for the movement of relatively large volumes of water. According to another preferred embodiment of the invention, the influencing member is arranged to take an inactive position when it is moved outside the inner space, in which inactive position it is arranged at a smaller angle in relation to the longitudinal direction of the flexible element than in the active position. Hereby, conditions are created for the achievement of an efficient device with regard to its size.

According to another embodiment, the movement of the influencing member is of a to-and-fro type. This means that the device is well suited for the achievement of low-frequent pressure waves thanks to the fact that a large liquid volume is influenced and that such a movement is relatively simple to obtain by a relatively high accuracy with regard to the frequency of these pressure waves.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of preferred embodiments of the invention, described by way of example with reference to the drawings attached, follows below.

Fig. 1 discloses a first preferred embodiment of the device according to the invention in a sectional perspective view.

Fig. 2 discloses a cross-section of the device according to fig. 1.

Fig. 3 discloses a second preferred embodiment of the device according to the invention in a perspective view.

Fig. 4 discloses a third preferred embodiment of the device according to the invention in a sectional perspective view.

Fig. 5 discloses a front view of a first example of an influencing member of the device, which is arranged in an active, closed position. Fig. 6 discloses the influencing member in fig. 5 in a side view.

Fig. 7 discloses the influencing member in fig. 5 in an inactive, open position in a side view.

Fig. 8 discloses a second example of an influencing member of the device, which is arranged in an active position in a side view.

Fig. 9 discloses the influencing member according to fig. 8 in an inactive position in a side view.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Fig. 1 discloses a first preferred embodiment of the device according to the invention. The device includes a framework 1 , a plurality of influencing members 2, and an arrangement 3 for moving the influencing members 2 in a movement relative to the framework. The moving arrangement 3 includes a first flexible element 2, to which the influencing members are connected. The flexible element 4 runs over a first pair of guiding members 5, 6, which are arranged at a distance from each other on the framework 1. The flexible element defines an elongated, preferably endless band.

The influencing members 2 have herein a plate-like shape. The guiding members are herein tooth-wheels. Of course, the guiding members may also be other components, such as pulleys, rolls, or the like. The flexible element 4 is herein a chain, but may, of course, also be other elements, such as a wire, a band, a belt, or the like. The guiding members 5, 6 delimit the extension of the flexible element 4 in its longitudinal direction. Of course, it is within the scope of the claims according to the invention to provide further guiding members between two outer guiding members 5, 6.

A power assembly, such as an electric motor, is suitably provided for driving the flexible element 4 around the guiding members 5, 6. The moving arrangement includes a second flexible element 7, which extends in parallel to the first flexible element 4 and runs over a second pair of guiding members 8, 9. The influencing members 2 are also connected to the second flexible element. The first 4 and second 7 flexible elements are provided at a greater distance from each other than the extension length of the influencing member transversely to the longitudinal direction of the elements, see fig. 2. In addition, the influencing members 2 are connected in an articulated manner to the flexible elements 4, 7. Hereby, pivoting of the influencing members 2 between the flexible elements 4, 7 is enabled.

The framework 1 has an inner space 11 which is delimited by delimiting means 10 and through which the influencing members are intended to be moved. The space 1 1 has a substantially constant inner cross-sectional area in the movement direction. The influencing members 2 have a substantially equally great effective area as the inner cross-sectional area of the space during a part of the moving movement extending in said space 1 1. This means that the movement of said liquid or gas through the space 1 1 may be performed substantially without losses in the form of leakage of said liquid or gas between the influencing members 2 and the delimiting means 10.

Herein the delimiting means 10 are continuous walls. The inner space 1 1 has a substantially rectangular cross-section. Furthermore, the framework 1 defines openings 12, 13 to the inner space 11. The openings 12, 13 are separated from each other by said continuous walls of the framework. During the movement of the influencing members 2, these will bring liquid from a first area located at a first 12 of the openings and deliver the liquid to a second area located at a second 13 of the openings. The framework is designed in such a way that a substantial distance exists between the openings 12, 13. The openings 12, 13 are separated by a distance, corresponding to at least half the periphery of the influencing member and being preferably at least as great as the periphery of the influencing member and suitably at least two times of the periphery of the influencing member.

Said influencing members 2 are arranged to take at least two different positions, namely an active position and an inactive position. The influencing members 2 are intended to be arranged in said active position when they are located in the inner space in the framework 1 , in which active position they substantially prevent said liquid or gas from by-passing the same. The influencing members are intended to be arranged in said inactive position when they are located outside the inner space. The influencing members 2 are in the inactive position arranged at a smaller angle relative to the longitudinal direction of the flexible elements 4, 7 than in their active position. The influencing members 2 extend suitably substantially in parallel to the flexible elements in the inactive position. The guiding members 5, 6 and 8, 9 are provided on the framework 1 at each of the openings 12, 13 in such a way that the flexible elements 4, 17 partly extend outside the space 1 1. The framework 1 has a channel 14, which is separated from the space 1 1 and through which the moving movement of the influencing member extends. The influencing members 2 are intended to be provided in said inactive position when they are located in the channel 14.

The device includes means 15 for supporting the influencing members 2 during the movement in the space 1 1 from one side of the space being substantially opposite in relation to the edge of the respective influencing member, which is connected to the flexible elements 4, 7 in order to maintain the influencing members 2 in said active position during the movement in the space 1 1. The flexible elements 4, 7, to which the influencing members 2 are connected, extend at the top of the inner space 1 1 , whereas said support means 15 are provided at the bottom of the space 1 1. The support means 15 includes at least a third flexible element 16, which extends in parallel to the first flexible element 4 over a third pair of guiding members 17, 18. A number of support members 19 corresponding to the number of influencing members 2 are connected to the third flexible element 16 in order to support the influencing members 2 behind these during the movement in the space 1 1. The support members 19 suitably project towards the inner space 1 1 from the flexible elements 16. The device includes a fourth flexible element 20, which extends in parallel to the third flexible element 16 over a fourth pair of guiding members 21 , 22. Said support members 19 are also connected to the fourth flexible element 20. The support member 19 is herein an elongated rib, which extends substantially perpendicular to the longitudinal direction of the third flexible element 16.

Between the first 4 and the second 7 flexible elements, a delimiting means 10 in the form of a wall-portion 10a is provided for delimiting the inner space 1 1. In the embodiment disclosed in fig. 1 , the space 1 1 is delimited at the top of the wall portion 10a. The guiding members 5, 8 are provided at a sufficient distance from an edge adjacent thereto of the wall portion 10a in order to enable the influencing members 2 to pivot between the guiding members 5, 8 and said edge. Consequently, the guiding members 5, 8 are provided at a distance from said inner space 1 1. The distance between the guiding members 5, 8 and said edge of the wall portion 10a exceeds at least the length of the projection of the influencing member 1 1 in the longitudinal direction of the flexible element in the inactive position of the influencing member.

The device includes an arrangement 23 for bringing the influencing members 2 from the inactive position outside the space 1 1 to the active position in the space 1 1. The arrangement 23 includes an arm 24 arranged to be moved in a path intersecting the moving path of the influencing members 2 outside the inner space 1 1 in such a way that the influencing members are brought to the active position. The arrangement 23 is provided at the opening 12 in the proximity of said edge of the wall portion 10a in such a way that the arm 24 influences the influencing members 2 in such a way that the edge of the influencing members, which is opposite to the suspension edge of the flexible elements 4, 7, is brought into the inner space 11 . The arm 24 is attached to a rotatable shaft. By synchronising the rotational speed of the shaft to the rotational speed of said guiding member, the arm may be brought to influence each of the successive influencing members 2 when they are moved to said edge of the wall portion 10a. The shaft is suitably mechanically connected to the guiding members 5, 8. In the example illustrated, the arrangement 23 includes two further flexible elements 38, 39, which each runs about a further guiding member 40, 41 and one of the previously mentioned guiding members 5, 8. The shaft extends between the guiding members 40, 41.

According to an alternative to the use of said arrangement 23, the gravity may be utilised. By providing the flexible elements 4, 7, as illustrated in fig. 1 , at the top of the space 1 1 , i.e. at a level above the space 1 1 , the gravity may be utilised to generate a pivoting of the influencing members 2 for bringing these from the inactive position to the active position after passing of the edge of the wall portion 10a. The direction of the device, when utilising the gravity, is thus important for the achievement of the latter function.

Fig. 2 discloses schematically a cross-section of the device according to fig. 1. The inner space has herein a substantially rectangular shape. However, the inner space 1 1 may, within the inventive claims, also have a circular, oval, or polygon-like or any other shape. In order to obtain a proper sealing of the influencing member 2 to the delimiting means, the influencing members 2 preferably have the same shape and an equally great or somewhat smaller effective area in relation to an inner cross-sectional area of the inner space 11. Said delimiting means 10 may, in addition to the continuous walls mentioned above, also be flexible elements in the form of substantially flat-shaped bands.

For counteracting leakage between the influencing means 2 and the delimiting means 10 during the movement of the influencing members 2, it is appropriate that each of the influencing members has an resilient strip, for instance of rubber, at its edges facing the delimiting means. Fig. 3 discloses a second preferred embodiment of the device according to the invention. This embodiment differs from the one disclosed in fig. 1 in that the influencing members 26 are arranged obliquely within the space 1 1 in the active position, and that said support means 37 is one of said delimiting means, namely a wall portion 10b. The influencing members 26 are intended to slide on and along said second wall portion 10b during the movement through the inner space 1 1. Each of the influencing members 26 has for this purpose a greater extension length from its edge 27, which is connected to said flexible element 4, 7, to an edge 28 of the influencing member located opposite to the connecting edge 27, than the vertical distance between the upper wall portion 10a and the lower wall portion 10b. The lower wall portion 10b is designed with a low coefficient of friction in order to generate an as small resistance as possible to the movement of the influencing member.

The device according to the first and the second embodiment is also well suited to be employed as a propulsion member for the transport of water carried crafts. In contrast to conventional propulsion members in the form of, for instance, propellers, a propulsion member generating a low sound level is obtained by the device according to the invention. Consequently, the device is suitable for being used, for instance, in marine areas having a sensible environment with respect to animal life. Furthermore, cavitation defects are usual in conventional rotating propulsion members in the form of propellers, which defects do not arise on the device according to the invention.

Fig. 4 discloses a third preferred embodiment of the invention according to the invention. The device includes merely one influencing member 29. The influencing member 29 is provided within the inner space 1 1 of the framework 1. The influencing member 29 is connected to the flexible elements 4, 16 located opposite to each other at opposite ends of the influencing member. The movement of the influencing member 29 is of a to-and-fro type. During said to-and-fro movement of the influencing member 29 in the space, said first and second area will alternately and concurrently with the to-and-fro movement be located at a respective of said openings 12, 13, provided that the influencing member 29 has an active position, in which it in an effective manner influences said liquid or gas. Preferably, the influencing member 29 is connected in an articulated manner to the flexible elements. This embodiment of the invention is well suited to be used in seismology and tomography, when the to-and-fro movement in a relatively simple way may be repeated continuously during a pre-determined time period at a high accuracy for generating low-frequent pressure waves.

The figures 5-7, and 8-9 illustrate two different examples of devices of the influencing member to disclose a one-way valve function. An overpressure is formed merely when the influencing member 30 is transported in a forward direction, see the arrow Y in fig. 6. The figs. 5 and 6 disclose the influencing member 30 when this is located in the active position. Fig. 7 discloses the influencing member 30 in an inactive, open position. The influencing member 30 includes a plate-like part 33, which via hinge means 31 is connected to a frame-like part 32. The frame-like part 32 is in turn connected to one or several of the flexible elements. When the influencing member 30 is brought to perform the backward movement, to the left in fig. 7, see the arrow Z, the influencing member is open and thus a water-flow through the frame 32 is permitted. The plate-like part 33 is provided when the influencing member is brought from the backward movement to the forward movement, in order to give the influencing member such a torque around the hinge joint 31 that the influencing member is brought to the active, closed position.

The example disclosed in figs. 8 and 9 differs from the example disclosed in figs. 5-7 in that the influencing member 34 merely is connected to said flexible elements 4 at one edge. The frame-like member is herein replaced by a stopping arm 35. The influencing member 34 will here, in the same way as according to the first example, act as a one-way valve and merely permit an overpressure to be formed when the influencing member is moved in the forward direction, see the arrow Y in fig. 8.

The examples of the influencing member described above and illustrated in figs. 5-9 are particularly suitable in the case that the influencing member performs a to-and-fro movement in said space in the framework and in particular during generation of pressure waves. In addition, such a movement is usable during pumping of large volumes of water from a first position to a second position, for instance located at a higher level, through said inner space.

To the power assemblies, which are connected to said guiding members, a control unit is preferably connected. The control unit is arranged to control the speed and direction of the influencing member. In the case that a plurality of flexible elements are provided, the control of these is suitably synchronised. In the embodiment illustrated in fig. 1 , this is illustrated by a drive-belt 36, which connects the upper and lower elements 7 and 20 in the framework.

A desideratum of the device according to the invention is the possibility to be able to integrate the device for pressure generation with further methods for tomography and reflection seismology. According to the device of the invention, one may, as has been described above, via the control unit and the power assemblies vary the speed of the influencing members in relation to the framework, and thus the frequency of the transmitted pressure waves may be controlled to desired values.

By the device according to the invention it is possible to generate pressure waves of a low frequency, from 0 Hz to at least 10 Hz. For this purpose large volumes of water of low pressure are moved.

The device according to the invention is, according to the embodiments described above, well suited to be employed as a pump for moving very large volumes of liquid. For instance, it is possible to dimension the device in such a way that flows of at least 5 m³/s are generated. The influencing member is, for instance, designed with an effective area of about 1 m². By effective area is meant herein an area substantially corresponding to the cross- sectional area of said space.

During the use of the device for generating pressure waves in water, a laminar flow is obtained when the influencing member is moved at a relatively low speed. By providing the influencing member to be moved along a substantially rectilinear path when it influences said liquid or gas, a substantially coherent water-flow is obtained, which means that the flow has a great range.

A pumping of liquid from a first position to a position located at a higher level in relation to the first position may, for instance, be used during purifying of water in connection with oil discharge, wherein large quantities of water may be transported up to a water- carried platform and filtered before it is returned to the contaminated water volume. Furthermore, such a pumping may, for instance, be used for water-regulating in areas subjected to flooding, in connection with regulation of poles, and in connection with energy storage. For instance, energy storage may be obtained in connection with wind power plants by pumping of water to a higher level.

The device according to the invention is also usable for moving of water in lakes having a lack of oxygen in order to increase the oxygen content in these lakes.

In all described embodiments of the device according to the invention, the influencing member may have a shape differing from the plate-like shape. For instance, the influencing member may have a curved, bucket-shaped design. The number of influencing members per flexible element is not limited to the number disclosed in the preferred embodiments but may, of course, amount to a number differing therefrom. In connection with pressure wave generation, the device may, for instance, be provided at the bottom by means of a frame, or be maintained in a position in the water by means of a wire or a frame from a suitably floating craft.

The areas formed during moving of the influencing member in a movement relative to the framework and having a lower pressure than the surrounding water and a higher pressure than the surrounding water, respectively, correspond to an inlet area and an outlet area of the device. These inlet and outlet areas are mostly articulated when the framework is designed with a through-going opening. The end of the space, from which the influencing member is moving, thus form an inlet end and the end of the space, towards which the influencing member is moving, thus forms the outlet end, wherein water is brought from the inlet to the outlet end within the space.

Since at least one influencing member continuously is located in the space in the framework and arranged in the closed position, i.e. substantially preventing water from by-passing the influencing member, this member will bring water in movement in a coherent flow through the framework towards the high-pressure area when the flexible element or elements are moving.

It is pointed out that the embodiments described above and illustrated on the drawings are to be considered as exemplifying. Consequently, the invention may be realised in other ways, while maintaining the basic inventive thought. In particular, it is pointed out that persons skilled within this field, after having received knowledge about the solution according to the invention, of course, are capable to perform different re-constructions of the exemplified embodiments without leaving the scope of the patent protection.

For instance, the arrangement for moving the influencing member and the influencing member may be arranged in such a way that an area of lower pressure than that of the surrounding water is formed and an area of a higher pressure than that of the surrounding water is formed without the provision of the space defined by said delimiting means, wherein these areas are separated in such a way that water cannot flow directly from the high-pressure area to the low-pressure area. This may, for instance, be performed by giving the influencing members a bucket-like shape or by arranging the influencing members relatively close to each other, so that water is "maintained" in the gap between the influencing members to influence a large quantity of water by the device.

For instance, two plate-shaped, flexible elements running over the guiding members may form two elongated surfaces, which are parallel to and facing each other. By providing two wall portions perpendicular to these surfaces, an inner space may be defined with a through-going passage having a rectangular inner cross- section.

For achieving the to-and-fro movement, it is also possible to provide a screw-like element, by which the influencing member/members are connected, wherein the screw-like element is brought to rotate via, for instance, an electric motor. The influencing member is in such a way brought in a direction and the backward movement is obtained by bringing the screw-like element to rotate in the opposite direction. Of course, it is also possible, as an alternative to the embodiment of the invention illustrated in fig. 1 , to provide the influencing member on the third flexible element as well as on the first flexible element. Preferably, support members are, in this case, provided on the first as well as the third flexible element. Hereby, a relatively rigid device is obtained, which does not tend to be turned or rotate in water.

In order to achieve a continuous pumping function, one of said influencing members is continuously located in the inner space.

Claims

1. A device for moving a liquid or a gas, characterised in that the device includes a framework (1 ), at least one influencing member (2, 26, 29, 30, 34) intended for influencing said liquid or gas, and an arrangement (3) for moving the influencing member in a movement in relation to the framework in order to bring liquid or gas from a first area and to deliver liquid or gas to a second area substantially separated from the first area.

2. A device according to claim 1 , characterised in that the influencing member (2, 26, 29, 30, 34) is arranged to be moved along a substantially straight path when it influences said liquid or gas.

3. A device according to claim 1 or 2, characterised in that the moving arrangement (3) includes at least a first flexible element (4), and that the influencing member (2, 26, 29, 30, 34) is connected thereto.

4. A device according to claim 3, characterised in that the flexible element (4) runs over a first pair of guiding members (5, 6), which are provided at a distance from each other on the framework (1 ).

5. A device according to claim 3 or 4, characterised in that the influencing member (2, 26, 29, 30, 34) is connected in an articulated manner to said flexible element (4).

6. A device according to claim 4 or 5, characterised in that the moving arrangement (3) includes a second flexible element (7), which extends in parallel to the first flexible element (4) and runs over a second pair of guiding members (8, 9), and that the influencing member (2, 26, 29, 30, 34) also is connected to the second flexible element (7).

7. A device according to claim 6, characterised in that the first (4) and second flexible elements (7) are provided at a greater distance from each other than the extension length of the influencing member transversally to the longitudinal direction of the elements (4, 7), at least in a portion of the influencing member which is adjacent to the elements.

8. A device according to any one of the preceding claims, characterised in that the framework (1 ) has an inner space (1 1 ) delimited by a delimiting means (10, 10a, 10b) and at least two openings (12, 13) leading to the space, that at least a part of the moving movement of the influencing member (2, 26, 29, 30, 34) extends in the space, and that the influencing member is arranged to form, during moving of the latter, said first and second area, at a first and a second of said openings, respectively.

9. A device according to claim 8, characterised in that said influencing member (2, 26, 29, 30 34), in an active position during said part of the moving movement extending in the space, has an essentially equally effective area as an inner cross-sectional area of the space (1 1 ) along said part.

10. A device according to claim 8 or 9, characterised in that said device includes means (15, 37) for supporting the influencing member (2, 26, 29) during the movement in the space from a substantially opposite side of the space in relation to the edge (27) of the influencing member, which is connected to the flexible element in order to maintain the influencing member in an active position during the movement in the space.

11. A device according to claims 5 and 10, characterised in that the influencing member (26) has a greater extension length from its edge (27), which is connected to said flexible element (4, 7), to an edge (28) of the influencing member, which is located opposite to the connecting edge, than the distance between a first delimiting means (10a) adjacent to the connecting edge and a second delimiting means (10b) opposite to the first delimiting means.

12. A device according to claim 11 , characterised in that said support means (37) is a wall-portion (10b) of the framework.

13. A device according to claim 3 or 4, and claim 10 or 1 1 , characterised in that said support means (15) includes at least a third flexible element (16), which extends in parallel to the first flexible element (4) over a third pair of guiding members (17, 18).

14. A device according to claim 13, characterised in that said support means (15) includes at least a support member (19), which is connected to the third flexible element (16) and which is arranged to support the influencing member (2) behind the latter during the movement in the space.

15. A device according to claim 14, characterised in that support member (19) is an elongated rib, which extends substantially perpendicularly to the longitudinal direction of the third flexible element (16).

16. A device according to claim 14 or 15, characterised in that said support means (15) includes a fourth flexible element (20), which extends in parallel to the third flexible element (16) over a fourth pair of guiding members (21 , 22), and that the support member is connected to the fourth flexible element.

17. A device according to any one of claims 8-16, characterised in that said guiding members in at least one of the pairs are provided on the framework (1 ) at each of the openings (12, 13) in such a manner that one flexible element running over the guiding members extends partly outside the space.

18. A device according to any one of claims 8-17, characterised in that the influencing member (2, 26, 30, 34) is arranged to take an inactive position, in which it is arranged at a smaller angle in relation to the longitudinal direction of the flexible element than in an active position, in which it is intended to influence said liquid or gas.

19. A device according to claims 17 and 18, characterised in that the influencing member (2, 26) is arranged to take the inactive position when it is moved outside the inner space (1 1 ).

20. A device according to claim 19, characterised in that the device includes an arrangement (23) for bringing the influencing member (2, 26) from the inactive position outside the space to the active position in the space.

21. A device according to claim 20, characterised in that said arrangement (23) includes an arm (24) arranged to be moved in a path intersecting the moving path of the influencing member outside the inner space in such a way that the influencing member is brought towards the active position.

22. A device according to any one of the claims 13-17, character- ised in that said device has merely one influencing member (30), which is connected at opposite ends of the same, to the flexible elements located opposite to each other.

23. A device according to any one of claims 1 -18 or 22, characterised in that the movement of the influencing member (30) is of a to-and-fro type.

24. Use of the device according to any one of the preceding claims in order to generate pressure waves in water.