WO1995023259A1

WO1995023259A1 - Delivery of sea water using tidal movements

Info

Publication number: WO1995023259A1
Application number: PCT/NZ1995/000008
Authority: WO
Inventors: George Walker
Original assignee: George Walker
Priority date: 1994-02-28
Filing date: 1995-01-27
Publication date: 1995-08-31
Also published as: AU1547395A

Abstract

A sea water pipe system is disclosed which comprises a sea pipe (1) connected to an intake pipe (2) at the onshore end and with inlet pipes (3) at the offshore end. A grille (13) is preferably secured over each inlet pipe (3) to prevent solid matter from flowing into the sea pipe (1). As the incoming tide rises, sea water is drawn into intake pipe (2) at tide level 4 and flows into pond (5). A second pond (7) is constructed adjacent pond (5) to allow water to overflow from pond (5) into pond (7). An outlet pipe (8) may extend from pond (7) to the sea with an outlet valve (22) being used to prevent water from an incoming tide being drawn through outlet pipe (8) into pond (7). The outlet valve (22) may be opened at low tide to allow waste water to drain from the ponds.

Description

DELIVERY OF SEA WATER USING TIDAL MOVEMENTS

TECHNICAL FIELD

The present invention relates to a method and installation for delivering sea water to a container. More particularly, but not exclusively, the present invention relates to the supply of nutrient rich sea water, drawn from the sea via pipes, to an onshore aquacultural complex or to any plant requiring a regular supply of suitable sea water.

BACKGROUND OF THE INVENTION

Onshore aquacultural complexes grow various ocean flora and/or fauna. These complexes generally require a regular supply of nutrient rich sea water for the particular plants and/or sea animals being cultivated. These nutrients may include sea foods such as phytoplankton and zooplankton which are consumed by many sea creatures, including bivalve molluscs.

Onshore aquacultural complexes employ a variety of pumping systems to acquire sea water. One such system is to use a motor-controlled impeller water pump which pumps sea water from below the low tide level to the complex. This system, however, has a few disadvantages. Water pumps are costly to run as they require a regular supply of fuel or power and most pumps have high ongoing maintenance costs.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a pipe system to supply nutrient rich sea water to an aquacultural complex which overcomes at least some of the abovementioned problems, or at least to provide the public with a useful choice.

According to one aspect of the invention there is provided an installation for the delivery of sea water from a desired depth in the sea to a container at a higher level comprising: a conduit having an inlet orifice positioned a predetermined distance above the sea floor and an outlet orifice connected to a container at a level higher than the inlet orifice, between high and low tide levels, the arrangement being such as to allow water to flow into the container through the conduit when the sea level is above the outlet orifice invert level.

According to a further aspect of the invention there is provided a method for delivering sea water from a desired depth in the sea to a container positioned at a higher level than that depth comprising: providing a conduit having an inlet orifice and an outlet orifice which is connected to a container. the outlet orifice being positioned between the high and low tide levels than allow sea water to flow through the conduit and into the container as the tide rises above the outlet orifice invert level.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1: shows a side view of the apparatus according to one embodiment of the invention.

Figure 2: shows a side view of the sea pipe according to an alternative embodiment of the invention. Figure 3: shows a cross-sectional view of a pond layout according to a preferred embodiment of the invention. Figure 4: shows a perspective view of a basic aquacultural complex.

BEST MODE FOR CARRYING OUT THE INVENTION Referring to figure 1, a side view of a pipe system according to a preferred embodiment is shown. A sea pipe 1 descends from joint A to the sea floor to a predetermined depth. The sea pipe 1 at the offshore end is joined to inlet pipes 3. The inlet pipes 3 extend from the sea pipe 1. The entrance to the inlet pipes are positioned between the sea surface and sea floor to draw nutrient rich sea water into the inlet pipes 3. The inlet pipes 3 are preferably spaced to allow a large volume of nutrient rich sea water to be drawn from the sea.

The inlet pipes 3 extend vertically from the sea floor to a level at which the entrance of the inlet pipes 3 are at least approximately 2.5 metres above the sea floor and at least approximately 12 metres below the sea surface. A section of the inlet pipes 3 are preferably encased in concrete blocks 14.

A grille 13 is secured over the entrance of each inlet pipe to prevent solid matter from flowing into the inlet pipes. Alternatively, a mushroom-shaped cover may be fastened above each intake pipe to allow sea water to flow underneath and into each intake pipe.

An advantage with positioning the entrance of the inlet pipes 3 at this sea level is that generally only nutrient rich sea water, free of sand or surface fouling, will be drawn into the cultivation ponds. Another advantage with taking sea water from this depth is that such water is generally free of fouling. such as algal blooms, which are detrimental to ocean flora and fauna.

The sea pipe 1 is connected at joint A to intake pipe 2 at a predetermined sea level between the high tide level 4b and the low tide level 4a. The intake pipe 2 extends into pond 5, which is preferably lined by concrete. Pond 5 is preferably located in an onshore aquacultural complex.

It will be appreciated that the water drawn from the intake pipe may be into a container made of durable material such as metal and/or concrete and/or plastic, and be constructed on rocks adjacent the sea or on the beach or onshore at a level below the high tide level.

A barrier 21 separates pond 5 from pond 7. An outlet pipe 8 is connected to pond 7 and extends horizontally to outfall 9. An outlet valve 22 is positioned in outlet pipe 8 to prevent the incoming tide from being drawn into pond 7 and to prevent the premature release of waste water from the ponds. A second valve (not shown) may be positioned at the outfall 9 adjacent the beach 20. The second valve may be closed after waste water is released. A filter system may be fitted at the outfall 9 (not shown) to prevent waste from flowing into the sea. An inspection porthole 10 may be joined to intake pipe 2. An intake valve 16 are preferably installed in intake pipe 2 between the pond 5 and the porthole 10 to control the volume of water flowing into pond 5.

The intake pipe invert level 4 is preferably set at a level just above the low tide level 4a to allow water to flow through intake pipe 2 into pond 5 as the incoming tide rises. The intake pipe 2 may be horizontal or subject to an upward or downward gradient. In another embodiment the intake pipe 2 has a downward gradient of 0.02% per 100 metres from the intake pipe invert level 4 at joint A to pond 5. This downward gradient allows gravity to assist the flow of water into pond 5.

It will be appreciated that more than one intake pipe, sea pipe and outlet pipe may be incorporated in an embodiment of the invention, and any one pipe may be made of durable material such as metal, concrete or plastic or any combination thereof.

Preferably the sea pipe and intake pipe are one metre in diameter. A pipe of this diameter will draw up to approximately 300 litres of sea water per second into the cultivation pond 5. This means up to approximately 5 million litres of water is available per incoming tide. A pipe of one metre will also allow a diver to inspect and clean the sea and intake pipes.

If smaller diameter intake and sea pipes are used so as not to allow for diver inspection, then it may be beneficial to employ at least one further sea pipe and intake pipe to allow for periodic flushing of one pipe while allowing at least one further intake pipe and sea pipe to function.

Referring to figure 2, a side view of the sea pipe according to an alternative embodiment of the invention is shown. A sea pipe 1 extends downward to the sea floor. Concrete blocks 16a, 16b, 16c, and 16d of differing heights are positioned to set the inlet entrance 17 at least 2.5 metres above the sea floor and at least 12 metres below the sea surface. Alternatively, metal structures, such as a triangular frame, may be used with or instead of concrete blocks to support the sea pipe 1.

Referring to figure 3, there is shown a preferred arrangement of cultivation ponds fed with nutrient rich sea water. The intake pipe 2 extends into upper pond 5. The upper pond 5 is filled with water to at least level 5a. A water barrier 18 separates the upper pond 5 from a middle pond 6 and is constructed to the height of level 5a. A water barrier 19 separates the middle pond 6 from a lower pond 7 and is constructed to a height of level 6a. The middle pond

6 has a low tide level 6a, set below the upper pond minimum level 5a. The lower pond 7 has a low tide minimum level 7a, set below the middle pond level 6a.

The outlet pipe 8 has an outlet valve 22 (shown in figure 1) which is adapted to drain water from the ponds when the water level is above levels 5a, 6a and 7a. While the outlet valve 22 remains closed, water may be retained in the ponds to level 4b at low tide.

It will be appreciated that any number of containers or ponds may be incorporated in an embodiment of the invention.

Referring to figure 4, a perspective view of an aquacultural complex is described. Various types of installations may be constructed utilising the essential aspects of the invention. In this particular example inlet pipes and containers are constructed in conjunction with housed areas 11 which draw water from pond 5 and recirculate it back to drainage pond 7. The operation of the preferred embodiment of the invention as shown in figure 1 and the cultivation ponds in figure 3 is now described. Initially the sea water level is at low tide level 4a and outlet valve 22 is closed. Nutrient rich sea water freely flows through inlet pipes 3 and in a section of sea pipe 1. When the incoming tide rises above intake pipe invert level 4, sea water flows into intake pipe 2 and into upper pond 5 and will continue to flow until the tide level recedes below intake pipe invert level 4 or intake valve 16 is closed.

As sea water flows into upper pond 5, an immediate overflow into middle pond 6 and subsequent overflow into lower pond 7 occurs. The water level of lower pond 7 then rises to level 6a at which point the water merges with that of pond 6 and continues to rise to level 5a. The water level in ponds 5, 6 and 7 will then rise to match the level of high tide level 4b unless intake valve 16 is closed. Intake valve 16 may be closed to control the level of water flowing into the cultivation ponds.

In a case where the intake valve 16 is open, the water level in ponds 5, 6 and 7 will fall as the tide recedes and will continue to fall until the water level reaches the intake pipe invert level 4. The outlet valve 22 at the pond end of outlet pipe 8 is then opened and water will drain further from the ponds until the tide recedes below the invert level of outlet pipe 8. The water level in pond 5 will f ll to level 5a, the water level in pond 6 to level 6a, and the water level of pond 7 to level 7a. Level 7a corresponds with the outlet pipe invert level at the pond end. The outlet valve 22 is then closed.

The pond levels remain at this low level until the next incoming tide brings a further supply of sea water through intake pipe 2. Further filling and draining cycles continue in the same manner.

It will be appreciated that the pond dimensions may be determined by the pipe inflow capacity which is proportional to the diameter of the pipes used.

The site location for a pipe system is preferably on low flats adjacent to a beach to minimise the excavation work required to construct the ponds. It will be appreciated that as the tide rises, the inflow of sea water continues until the pond level reaches the high tide level. Therefore, if the intake pipe is adapted with valve means and/or has an upward gradient from the sea end to the ponds, then the ponds need not be excavated as deeply as otherwise. Where in the foregoing description reference has been made to specific components or integers having known equivalents then such equivalents shall herein be incorporated as if individually set forth.

Although this invention has been described by way of example and with reference to possible embodiments thereof it is to be understood that improvements and/ or modifications may be made thereto without departing from the scope of the invention.

INDUSTRIAL APPLICABILITY

Although the apparatus and method of the invention may find application in a wide variety of systems, the invention is considered particularly suitable for use in drawing sea water to an onshore aquacultural complex.

Claims

1. An installation for the delivery of sea water from a desired depth in the sea to a container at a higher level comprising: a conduit having an inlet orifice positioned a predetermined distance above the sea floor and an outlet orifice connected to a container at a level higher than the inlet orifice, between high and low tide levels, the arrangement being such as to allow water to flow into the container through the conduit when the sea level is above the outlet orifice invert level.

2. An installation as claimed in claim 1 wherein the inlet orifice is positioned between the sea surface and the sea floor to draw the maximum amount of nutrients from the sea into the container.

3. An installation as claimed in claim 1 wherein a plurality of inlet orifices are adapted to be positioned within a predetermined range of heights between the sea surface and the sea floor to maximise the amount of nutrients drawn from the sea.

4. An installation as claimed in any one of the preceding claims wherein the container is provided with an outlet orifice to allow sea water to drain from the container.

5. An installation as claimed in claim 4 wherein the container outlet orifice is provided with filter means to prevent waste from passing through the container outlet orifice.

6. An installation as claimed in either claim 4 or 5 wherein the container outlet orifice is a conduit positioned to allow water to drain into the sea.

7. An installation as claimed in any one of claims 4 to 6 wherein the container outlet orifice is provided with first valve means which closes to prevent the flow of water through the container outlet orifice.

8. An installation as claimed in any one of the preceding claims wherein the conduit is provided with second valve means which closes when a predetermined water level is reached in the container.

9. An installation as claimed in any one of the preceding claims wherein the inlet orifice is provided with screening means to prevent large matter from flowing into the inlet orifice.

10. An installation as claimed in claim 9 wherein the screening means comprises a grille fastened across the inlet orifice.

11. An installation as claimed in claim 10 wherein the grille consists of a plurality of metal or plastic rods formed in a latticed pattern across the inlet orifice.

12. An installation as claimed in any one of the preceding claims wherein the rim of the container is positioned level with or above the high tide level.

13. An installation as claimed in any one of the preceding claims wherein two containers are provided, one container connected with the conduit outlet orifice and further provided with overflow means, the arrangement being such as to allow water to overflow from one container into the other container.

14. An installation as claimed in any one of claims 1 to 12 wherein at least three containers are provided, at least two being provided with overflow means, a first container connected with the outlet orifice of the conduit, the arrangement being such that water from the first container overflows into a second container which in turn overflows into at least a third container.

15. An installation as claimed in either claim 13 or 14 wherein the overflow means comprises an overflow conduit connected at a predetermined level between the walls of adjacent containers.

16. An installation as claimed in either claim 13 or 14 wherein the overflow means comprises a water barrier constructed between the walls of adjacent containers, the arrangement being such as to allow water to spill-over between adjacent containers.

17. An installation as claimed in any one of the preceding claims wherein the container is positioned onshore.

18. An installation as claimed in any one of claims 1 to 16 wherein the container is a metal tank adapted to be restrained and positioned in the sea water.

19. An installation as claimed in any one of claims 1 to 17 wherein the container is formed by embankments and/or lined by concrete to retain water.

20. An installation as claimed in any one of the preceding claims wherein the conduit and/or the container outlet orifice is a pipe made of metal, plastic or concrete or any combination thereof.

21. An installation as claimed in any one of the preceding claims wherein the conduit is a pipe of about one metre in diameter.

22. A method for delivering sea water from a desired depth in the sea to a container positioned at a higher level than that depth comprising: providing a conduit having an inlet orifice and an outlet orifice which is connected to a container, the outlet orifice being positioned between the high and low tide levels to allow sea water to flow through the conduit and into the container as the tide rises above the outlet orifice invert level.

23. A method for delivering sea water as claimed in claim 22 further comprising: controlling the flow of water from the container back down the conduit.

24. A method as claimed in claim 22 wherein the arrangement of the conduit and/or the container is as claimed in any one of claims 1 to 21.