WO2007046768A1

WO2007046768A1 - An arrangement for increasing the salt content in a water area

Info

Publication number: WO2007046768A1
Application number: PCT/SE2006/050413
Authority: WO
Inventors: Stefan NYSTRÖM; Peter Kjaerboe
Original assignee: Nystroem Stefan; Peter Kjaerboe
Priority date: 2005-10-19
Filing date: 2006-10-19
Publication date: 2007-04-26

Abstract

An arrangement for supplying water from a first water area (1 ) having a high content of salt in the water to a second water area (2) having a low content of salt in the water, wherein the first water area (1 ) and the second water area (2) are connected by means of a connection area (3). The arrangement comprises flow restricting means (6-8) arranged on the bottom in at least a part of a passage of the connection area (3). Said flow restricting means (6-8) are arranged to allow a flow of water through the whole passage when the water flows from the first water area (1 ) to the second water area (2) but to prevent a flow of water on a certain deep under the water surface in the passage when water flows from the second water area (2) to the first water area (1 ).

Description

An arrangement for increasing the salt content in a water area

PRIOR ART

The prevailing salt content in the Baltic Sea is a result of the quantity of seawater flowing in from the North Atlantic via the Danish straits and the quantity of fresh water supplied from the precipitation areas of the Baltic Sea. However, there is clear signs indicating that the salt content in the Baltic Sea is decreased as well as the exchange of salt water, which, for example, results in negative effects on the plant and animal life in the Baltic Sea.

About a quarter of the water exchanges between the North Atlantic and the Baltic take place via the narrow and shallow Oresund. The remaining water exchanges take place via the Large Belt and the Small Belt. The water exchanges are depending on the precipitation, the water control and the cyclone stream over Scandinavia. The increased water control has reduced the fluctuation of the water exchanges during the year. The water exchanges occur in a rapidly varying speed back and forth. However, this has substantially no influence on the salt content in the Baltic Sea since it is substantially the same water flowing back and forth. Only during very exceptional conditions, the influx of saline water is so prolonged that the salt water flows so far in the Baltic Sea that it does not flow out again. During such an influx, 200-400 km³ saline water can flow into The Baltic Sea. The heavier saline water is only very slowly mixed with the less saline water in the Baltic Sea and it flows substantially along the bottom until it reach the central basin of the Baltic Sea (The Gotland deep) after about half a year. The saline water pushes the old water in front of it, which often containing little or no oxygen and contains hydrogen sulphide.

SUMMARY OF THE INVENTION

The object of the present invention is to increase the influx of saline water from a saline water area, such as the North Atlantic, to a water area with a low salt content, such as the Baltic Sea in a relatively simple manner and to a reasonable cost.

This object is achieved by the arrangement according to the claims 1 and 9. The remaining claims states more detailed embodiments by which the above-mentioned object is achieved.

SHORT DESCRIPTION OF THE DRAWINGS

In the following, preferred embodiments of the invention are described as examples with reference to the attached drawings, in which:

Fig. 1 shows schematically a first arrangement for supplying salt water to the Baltic Sea, Fig. 2 shows a second arrangement for supplying salt water to the Baltic Sea,

Fig. 3 shows a third arrangement comprising a flow restricting device,

Fig. 4 shows a part of a fourth arrangement comprising a flow restricting device,

Fig. 5 shows the fourth arrangement in its entirety and Fig. 6 shows a connection area where a flow restricting- device may be applied. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Fig. 1 shows an arrangement for supplying salt water from the North Sea 1 to the Baltic Sea 2 via a connection area 3 which here is exemplified as the Kiel channel. The arrangement comprises a pump device 4 arranged in a suitable place in the North Sea 1 outside the outlet of the Kiel channel 3. Advantageously, the pump device 4 has a construction such that it is driven by wave energy. A very large tubular element 5 is arranged such that it extends from the pump device 4 to outlet of the Kiel channel. During operation of the arrangement, the pump device 4 pumps, by means of the wave energy, saline water from the North Sea 1 , via the tubular element 5, into the Kiel channel 3. The saline water flows thereafter through the Kiel channel 3 and out, via its outlet in the Kiel bay in the Baltic Sea 2. The bottom of the Kiel bay slopes substantially downwards towards an increased deep in the Baltic Sea 2. Thereby, the heavier saline water will flow along the bottom in direction to the central basin of the Baltic Sea (the Gotland deep).

Fig. 2 shows an alternative arrangement for guiding salt water into the Baltic Sea 2. In this case, a pump device 4 has been arranged outside the outlet of the Limfjorden in the Kattegat, which is a water area 1 with a relatively high content of salt. A 20 mil long tubular element 5 is here arranged such that it extends from the pump device 4 to the Small Belt, which is a connection area 3 till the Baltic Sea 2. During operation of the arrangement, the pump device 4 pumps saline water from Kattegat 1 , via the tubular element 5, through the Small Belt 3 and into the Baltic Sea 2. Fig. 3 shows a further alternative arrangement for guiding salt water from a saline water area 1 to a water area 2 with a low salt content. In this case, the arrangement comprises flow restricting-means, which are exemplified by means of plate shaped elements 6 attached on rollers 7. The rollers 7 are turnably arranged by means of cables 8 which are displaceably arranged by means of not disclosed power elements. The arrangement is arranged on the bottom in a passage of a connection area 3 between a saline water area 1 and a water area 2 with a low salt content. The arrangement is arranged on a determined deep under the water surface of the connection area 3. When water flows from the saline water area 1 to the water area 2 with a low salt content, the plate shaped elements are set in a turning position such that they obtain a substantially parallel extension to the main flow direction of the water. Thereby, the arrangement does not at all prevent the influx of salt water to the water area 2 with the low salt content. When the water flows in the opposite direction from the water area 2 with the low salt content to the saline water area 1 ,the plate- shaped elements 6 are set in a turning position such that they obtain a substantially perpendicular extension to the main flow direction of the water. Thereby, the flowing of water is blocked on a certain deep under the water surface in the passage. Thereby, the heavier saline part of the water, which is present on a certain deep under the water surface, is prevented from flowing out from the water area 2 with the low salt content. However, the lighter surface water having a low salt content is allowed to flow out from the water area 2 with the low salt content. Consequently, the heavier part of the water having the higher salt content is in a greater extent remained in the water area with the low salt content than the surface water with the low salt content. Thereby, the salt content will be increased in an effective manner in the water area 2 with the low salt content. Fig. 4 shows a part of an alternative arrangement for guiding salt water from a saline water area 1 into a water area 2 with a low salt content. Also in this case, the arrangement comprises flow restricting means in the form of plate-shaped elements 6 attached on rollers 7. The plate-shaped elements 6 here have a vertical extension. The rollers 7 are articulately attached in vertical foundations 9 arranged on the bottom in a connection area 3. The rollers 7 are turnably arranged by means of power elements not disclosed. The arrangement is arranged on the bottom in a passage of a connecting area 3 between a saline water area 1 and water area 2 with a low salt content. The vertical plates 6 are arranged such that they have an extension up to a determined deep under the water surface of the connection area 3. When water flows from the saline water area 1 to the water area 2 with a low salt content, the plate-shaped elements are set in a turning position such that they obtain a substantially parallel extension to the main flow direction of the water. Thereby, the arrangement does not substantially at all prevent the influx of salt water to the till water area 2 with the low salt content. When the water flows in the opposite direction from the water area 2 with the low salt content to the saline water area 1 , the plate-shaped elements 6 are set in a turning position such that they obtain a substantially perpendicular extension to the main flow direction of the water. Thereby, the flow of water is substantially blocked on said deep under the water surface in the passage. However, a smaller water flow can be provided since plate-shaped elements 6 discloses a less distance between each other in the vertical direction in the blocked statement.

Fig. 5 shows a complete arrangement constructed by the component disclosed in Fig. 4. The components are here joined together such that they extend along the bottom across a passage in a connection area 3 between a saline water area 1 and water area 2 with a low salt content. In order to facilitate passing of ships, the vertical plates 6 are arranged on a larger deep under the water surface in a fairway 10 having an extension through the connection area 3.

Fig. 6 shows, an example of the arrangement of said flow restricting means in the Large Belt in an about 10 km broad passage between the Lolland and the Lange land. The Large Belt and the Small Belt consist relatively deep connection areas 3 to the Baltic Sea 2 via which the main part of the water exchange occur to the Baltic Sea.

The present invention is not in any way restricted the above described embodiments but may be varied freely within the scopes of the claims.

Claims

1. An arrangement for supplying water from a first water area (1 ) having a high content of salt in the water to a second water area (2) having a low content of salt in the water, wherein the first water area (1 ) and the second water area (2) are connected by means of a connection area (3), characterised in that the arrangement comprises flow restricting means (6-8) which are arranged on the bottom in at least a part of a passage of the connection area (3), wherein said flow restricting means (6-8) are arranged to allow a flow of water through the whole passage when water flows from the first water area (1 ) to the second water area (2) but to prevent the flow of water on a certain deep under water surface in the passage when water flows from the second water area (2) to the first water area (1 ).

2. An arrangement according to claim 1 , characterised in that said flow restricting means comprises plate-shaped elements (6) which are turnably arranged between an open position when they have a substantially parallel extension to the main flow direction of the water and a blocking position when they have a substantially perpendicular extension to the main flow direction of the water.

3. An arrangement according to claim 2, characterised in that de plate-shaped elements (6) are attached to articulated rollers (7).

4. An arrangement according to claim 3, characterised in that the rollers (7) are turnably arranged by means of cables (8).

5. An arrangement according to claim 3, characterised in that the rollers (7) are turnably attached in vertical fundaments (9).

6. An arrangement according to any one of the preceding claims 2 to 5, characterised in that de plate-shaped elements (6) have a substantially vertical extension.

7. An arrangement according to any one of the preceding claims 2 to 5, characterised in that de plate-shaped elements (6) have a substantially horizontal extension.

8. An arrangement according to any one of the preceding claims 2 to 7, characterised in that de plate-shaped elements (6) are arranged on said deep under the water surface in a main part of the passage and on a larger deep in a fairway (10) extending through the passage.

9. An arrangement for supplying water from a first water area (1 ) having a high content of salt in the water, to a second water area (2), having a low content of salt in the water, wherein the first water area (1 ) and the second water area (2) are connected by means of a connecting area (3), characterised in that the arrangement comprises a pump device (4) arranged in the first water area (1 ) and flow restricting means (5) which itself or together with the connection area (3) defines a flow channel having an extension from the pump device (4) till the second water area (2), wherein the pump device (4) is arranged to pump saline water from the first water area (1 ), via said flow channel, to the second water area (2).

10. An arrangement according to claim 9, characterised in that the pump device is arranged to be driven by means of wave energy.