DEVICE FOR PRODUCING WAVES IN A LIQUID MEDIUM

Abstract: Device for producing waves in a liquid medium (2), said medium (2) being arranged in a pool or similar container (1), at least one side portion of said pool or container (1) including at least one air chamber (3, 3', 3''), communicating with the liquid medium (2) adjacent to the bottom surface of the pool or the container (1), a pump member (5, 5', 5'', 6, 6', 7, 7', 8, 8', 9, 10) being arranged to alternately expand/reduce an air cushion within the air chamber (3, 3', 3''), and thereby decreasing/increasing existing volume of liquid in the air chamber (3, 3', 3''), thus facilitating the formation of waves in the pool or the container (1) communicating with the air chamber (3, 3', 3''). By arranging at least two air chambers (3, 3', 3'') located adjacently to each other, and by arranging the expansion/reduction of associated air cushions phase shifted in time from each other, the wave producing effect can be further modified, as well as by changing the interval of time between expansion/reduction, or, by change of the volume change relationship for the air cushion. Different combinations of the above stated methods to accomplish a change in the wave formation characteristics can obviously also be used.

Description: Device for producing waves in a liquid medium The present invention relates to a device for producing waves in a liquid medium. With regard to swimming pools, it is often desirable to produce waves continously, in order to give persons in the pool a feeling, which is similar to swiπming in open water. Also with regard to other types of pools or containers with a liquid medium, it is sometimes desirable to produce waves, e.g. in order to perform a mixing operation, intended to prevent the liquid from forming zones based on differences in temperature or density. It is previously known to produce waves in a liquid medium within a pool or a similar container by means of reciprocally moving piston members, located adjacent to a side portion of the pool or the container. With regard to a swimming pool, said piston members may comprise of mainly disc-shaped members, extending adjacent to a side portion of the pool in a mainly parallel relationship to said side portion. Said disc- shaped members are connected by means of piston rods or similar means to drive members located outside the pool adjacent to the side portion where the disc-shaped members are located, and said disc-shaped members can thus perform a reciprocal movement in relation to the adjacent side portion of the pool, thereby producing waves in the liquid medium in the pool . A problem with the above type of installation for producing waves is to accomplish necessary sealing function at the point where the piston rods or similar members extend through the wall of the pool. Said members normally extend in a plane below the surface of the liquid in the pool, and necessary sealing at the wall of the pool is accomplished by the use of flexible rubber bellows or similar types of members, unable to prevent leakage from the pool when cracked or damaged. A further disad¬ vantage is, that the wave " producing members consist of reciprocally moving mechanical members, which must be arranged with surrounding protective guards, to prevent injuries on the persons in the pool. Such protective members also reduce the effective volume of the pool. The shape of the waves can not be varied to any large extent, since stroke length of the mechanical wave producing members obviously cause a restriction. Finally, previously known types of devices for producing waves are also extremely expensive, both with regard to manufacturing and installation costs. The object of the present invention is to disclose a device for pro¬ ducing waves, which overcomes all disadvantages stated above relating to previously known devices for corresponding purpose. The risk for leakage at intersection points in the wall of the pool is completely eliminated, the wave formation character can be varied extensively, and the costs for manufacture and installation are considerably reduced in relation to previously known types of devices. The major and characteristic features of a device according to the present invention are disclosed in the following main claim, and further characteristic features are disclosed in related subclaims. An embodiment of a device according to the present invention is more fully described below with reference to the accompanying drawings, and said embodiment is intended to serve as an example of an embodiment within the scope of the following claims. Fig. 1 is a logitudinal cross-sectional view of a swimming pool, having a device for producing waves according to the present invention located adjacent to one end portion of the pool. Fig. 2 is a plan view of the pool shown in Fig. 1 with the device for producing waves. Fig. 3 is a perspective view of the drive unit for the device for producing waves as shown in Figs. 1 and 2. With reference to Figs. 1 and 2, reference numeral 1 denominates a pool with a liquid medium 2. Adjacent to one end portion of the pool 1, a number of air chambers 3, 3 1 , 3" are arranged, adjacently to the bottom surface of the pool arranged communicating with the liquid medium 2 in the pool 1. In each one of the air chambers 3, 3', 3", which preferably extend vertically from the bottom plane of the pool is an air cushion, the size of which decides the volume of the liquid medium 2 that can flow into each air chamber 3, 3', 3" from the pool 1. Adjacent to the upper and from the bottom surface of the pool 1 direc- ted portion of each air chamber 3, 3', 3", a through flow opening 4, 4', 4" is arranged, communicating with a bellow-shaped pump member 5, 5', 5". Said bellow-shaped pump members 5, 5 1 , 5" have the planes directed from the pool T connected to a link system 6, 6', 7, 7', including link members 6, 6' internally connecting two adjacent bellow-shaped pump members 5, 5', 5", and also two connecting rods, 7 and 7' respec¬ tively, which connecting rods 7, 7' interconnect the link members 6, 6' and two cranking discs 8, 8'. A drive motor 9 is arranged with two from each other directed drive shafts, one being directly connected to a cranking disc 8, and the other being connected to the second cranking disc 8' by means of an intermediately located clutch 10. When the drive motor 9 is arranged to cause a rotary movement, a ' corre- sponding rotary movement results with regard to the cranking discs 8, 8', and the connecting rods 7, 7' attached to the cranking discs 8, 8', perform hereby a reciprocal movement. The movement of the connecting rods 7, 7' is transferred via the link members 6, 6 1 to the bellow- shaped pump members 5, 5', 5", which coπtinously with regard to volume are alternatively expanded or reduced. Said volume changes are trans¬ ferred via the through flow openings 4, 4*, 4" to adjacently located air chambers 3, 3', 3", thereby causing a corresponding change of volume with regard to the air cushion in each air chamber 3, 3*, 3", and thus also a corresponding change of liquid volume in each air chamber 3, 3', 3". Each air chamber 3, 3', 3" is thus acting as a pump means, which alternatively draws or pumps out a certain liquid volume from/to the pool 1 via the opening adjacent to the bottom plane of the pool 1 as each air chamber 3, 3 1 , 3" is arranged to communicate with the pool 1. Due to the movements of the bellow-shaped members 5, 5', 5", a con- tinous and alternating pumping action in/out of liquid medium 2 from the pool 1 is achieved into the air chambers 3, 3*, 3" located at one end portion of the pool 1, and said pumping action in/out causes the formation of waves in the pool 1, since the liquid surface is moved to/from the bottom surface of the pool 1. Hereby are waves generated in the liquid medium 2 in the pool 1. It is also possible to vary the type of waves formed, firstly by changing the revolution speed of the drive motor 9, and secondly by changing the point of attachment for the connecting rods 7, 7' to the cranking discs 8, 8* radially in relation to the centre of rotation, e.g. by means of a motor driven screw, whereby the stroke length of the connecting rods 7, 7' is changed. By means of the clutch 10, it is also possible to drive internally connected pairs of bellow-shaped members 5, 5 1 , 5" in a different pace to each other, whereby a further changed wave characteristic can be achieved. Accordingly, there are a number of ways in which the characteristics and the frequency of the waves can be changed, and the air cushion existing in each air chamber 3, 3', 3" prevents the liquid medium 2 from leaving the air chambers 3, 3', 3" through the through flow openings 4, 4', 4" and flowing into the bellow-shaped members 5, 5', 5", which would cause a risk for leakage. Said through flow openings 4, 4', 4" are preferably located in a plane above the surface plane of the liquid medium 2 in the'jpool 1, and the liquid surface in each air chamber 3, 3', 3" can also be arranged covered by means of a flexible membrane, in order to prevent leakage of the liquid medium in the air chambers 3, 3', 3" via the through flow openings 4, 4', 4" into the beloow-shaped members 5, 5', 5". By using air chambers 3, 3', 3", communicating with the liquid medium 2 in the pool 1, and by arranging said air chambers 3, 3', 3" an air cushion with a varying volume, a device for producing waves is accom¬ plished without any mechanical members extending through a wall in the pool 1, and no movable mechanical members are arranged in the pool 1 or in a space communicating with the liquid medium 2. As mentioned, it is also possible to vary the frequency and the character of the waves, with the use of a simple basic design. All movable members of the device are also located in a location which is accessable even if the pool 1 is filled with liquid, which simplifies service and maintenance. The described and shown embodiment can obviously be further modified in a number of ways, while maintaining the major and characteristic features of the inventive thought. Accordingly, the described and shown embodiment includes four air chambers 3, 3', 3" communicating with the pool 1. This number may be varied as desired from a single air chamber to any desired number. However, if only one air chamber is used, the possibility to create a phase shifted wave movement in side direction of * the pool 1 no longer exists, as previously described with reference the the use of the clutch 10. Furthermore, as a member for deciding the volume of the air cushions only bellow-shaped members 5, 5', 5" have been discussed, but it is obvious that also other types of members can be used, such as cylinder members with associated piston members, and also other types of known pump members. As a drive unit for the device has been stated a motor 9, which by * means of a rotary movement is driving the connecting rods 7, 7', thus causing desired linear drive movement. Necessary drive movement can obviously also be created in many other ways, e.g. hydraulically or pneumatically, by the use of one or a number of hydraulically or pneumatically driven cylinder members. Shown and described air chambers 3, 3', 3" have also been stated as preferably extending vertically, and said vertical direction is also a preferred direction of extension. For certain applications, it may be that a vertical direction of extension is less suitable, and that an inclined direction of extension in relation to the vertical plane causes desired effect, provided that the angle of inclination with regard to the horizontal plane is an angle directed upwardly. The device according to the present invention can thus be modified in a number of ways:within the scope of the inventive thought and the following claims, and the embodiment shown and described is only intended to serve as an example of an embodiment within the scope of the invention.

Claims: C L A I M S 1. Device for producing waves in a liquid medium (2), said medium (2) being arranged in a pool (1) or a similar container, said pool (1) or container having at least two air chambers (3, 3', 3") at one side portion communicating with the liquid medium (2) adjacently to the bottom surface of the pool (1) or the container and extending mainly vertically, or in an inclined direction upwards, from said bottom surface, and including an air cushion in contact with the liquid surface in each air chamber (3, 3', 3"), characteristic of that an individual pump member (5, 5', 5", 6, 6 1 , 7, 7', 8, 8', 9, 10) is arranged communicating with an air cushion in each individual air chamber (3, 3', 3"), said pump member (5, 5', 5", 6, 6', 7, 7', 8, 8', 9, 10) comprising of a bellow-shaped member (5, 5', 5") or a cylin- der/piston member for each individual air chamber (3, 3 1 , 3"), when influenced by a drive member (6, 6', 7, 7 ' , 8, 8', 9, 10) arranged to alternating expand/reduce the volume of the air cushion in each air chamber (3, 3 1 , 3"), thereby alternating increasing/decreasing the volume of liquid in each air chamber (3, 3', 3"), said change of liquid volume being arranged to cause the formation of waves in the liquid medium (2) within the pool (1) or the container. 2. Device according to claim 1, characteristic of that the drive member comprises of a rotary motor (9), the rotary movement of which is being arranged to be transferred by means of at least one cranking disc (8, 8') and at least one connecting rod (7, 7') to a mainly linear reciprocal movement, arranged to directly, or by means of an associated link member (6, 6'), be transferred to the pump member (5, 5', 5") for change of air cushion volume. 3. Device according to claim 1, characteristic of that the drive member comprises of a pneumatically or hydraulically operated piston member, the movement of which is arranged transferred to the pump member (5, 5', 5") for change of air cushion volume. 4. Device according to any of claims 1 - 3, characteristic of that the volume changing effect of the pump member (5, 5', 5", 6, 6 1 , 7, 7', 8, 8', 9, 10) on the air cushion in the air chamber (3, 3', 3") is infinitely variable between a predetermined maximum and minimum value. 5. Device according to any of claims 1 - 4, characteristic of that the operating frequency of the pump member (5, 5', 5", 6, 6', 7, 7', 8, 8', 9, 10) is infinitely variable between a predetermined maximum and minimum value. 6. Device according to any of claims 1 - 5, characteristic of that a preferably membrane-shaped member is arranged to separate tha liquid surface in each air chamber (3, 3', 3") from associated air cushion. OMPI

Inventors: ENGWALL B
Applicants: ENGWALL BERTIL, ENGWALL B
Application year: 1981
Main classification: F04D35
IPC codes: E04H4