WO2006092471A1

WO2006092471A1 - Device for transporting liquid in a marine environment et method for making a pipe therefor

Info

Publication number: WO2006092471A1
Application number: PCT/FR2005/000517
Authority: WO
Inventors: Félix BOGLIOLO
Original assignee: Sarl Via Marina
Priority date: 2005-03-03
Filing date: 2005-03-03
Publication date: 2006-09-08

Abstract

The invention concerns a pipe device for transporting liquid in a marine environment et method for making said pipe. It consists of a tube made of continuously woven synthetic fiber material, characterized in that it comprises ballasting and anchoring means consisting of a series of ballasting elements, preferably not mutually assembled, placed above the pipe (1) and contacting same on its upper half, said ballasting elements consisting each of two inclined planes (4, 5) connected by their common rectilinear (6) or rounded (7) ridge (6), such that said inclined planes (4, 5) form an angle a wherein is inscribed the circle formed by the section of the pipe along a plane perpendicular to its longitudinal axis. The invention is applicable to drinking water transport.

Description

DEVICE FOR TRANSPORTING LIQUID IN A MARINE ENVIRONMENT AND METHOD OF MANUFACTURING A PIPE FOR THIS

DEVICE

The present invention relates to a device for the transport of liquid by pipe in a marine environment and a method of manufacturing it.

A pipe is already known for transporting liquid in a marine environment consisting of a continuous woven material tube of synthetic threads, said material weighing 10 to 50 kg per linear meter of pipe. Such a device and its method of installation are described in the patent granted by applicant FR-A-2 786 246.

This patent provides a flexible, flexible hose that can be placed on seabed, can withstand corrosion of seawater and chafing on the seabed, withstand high internal and external pressures, and can withstand flow rates of several tens of m ³ per second.

This patent claims and describes a method of manufacturing such a pipe and its installation in the seabed. A floating support is placed on the water, said support supporting a circular loom. A plastic tube is woven using the circular loom, the weaving being carried out continuously, the end of the tube is fixed at a point of attachment on a seabed or on land, the floating support is moved for move away from the attachment bridge, dropping the tube by its own weight on the seabed.

However, such a method is quite expensive because it requires transport by floating support, that is to say by boat a mass of raw materials important for weaving the pipe and further it requires the transport of the loom. However, in the prior art, it has not been the problem of ballast pipe or that of its anchoring. Indeed, the pipe is intended to carry fresh water, and possibly even liquids whose density is lower than that of seawater. The freshwater-filled pipe floats since the fresh water is lighter This difference in density does not seem to be a problem, but it causes the pipe to float.

In addition the fresh water carried contains many gases, which can cause the swelling of the pipes and therefore their crack or even their bursting.

In addition, freshwater must flow relatively quickly from one point to another.

A problem that arises is to maintain the pipe filled with a liquid of lower density than that of seawater near the seabed.

In addition, the pipe FR-A-2786246 is woven material, relatively fragile, and therefore it can be damaged for example, in case of external aggression. Such external aggression can for example be an anchor launched from a boat on the surface of the sea, a net or a trawl or a line dragged by a fishing boat or a fisherman. The pipe must be protected from these attacks. A second problem that arises is to protect the pipe from external aggression.

On the other hand, the underwater currents are not very important in general, since the swell tends to fade very quickly as soon as one descends below the level of the sea. However, at the edge of the continental shelf (about 200 m), the slope can sometimes be important. Then there are "upwelling" and "downwelling" phenomena that locally create larger underwater currents. These currents applied to the surface of the pipes envisaged having between 2 and 5 m of diameter, can constitute important forces, likely to move the pipe. A third problem is to anchor the large diameter pipe to prevent its movement in the sea. Indeed, such a displacement can affect the strength of the pipe.

A fourth problem is to maintain a certain distance between the bottom of the sea and the bottom of the pipe.

A fifth problem is to reduce the cost of weaving the pipe. A sixth problem is to avoid hose damage by the fresh water being transported.

A seventh problem is to accelerate the speed of movement of the water carried inside the pipe.

An eighth problem is to avoid the water hammers that can occur during the transport of fresh water through the pipe.

To this end, the invention relates to a pipe intended for the transport of liquid in a marine environment consisting of a continuous woven material tube of synthetic threads, characterized in that it comprises weighting and anchoring means constituted by a succession of weighting elements, preferably not contiguous with each other, placed above the pipe and in contact therewith on its upper half, said weighting elements each consisting of two inclined planes connected by their edge common, rectilinear or rounded, so that said inclined planes form an angle α in which is inscribed the circle formed by the section of the pipe in a plane perpendicular to its longitudinal axis. Such a device with two inclined planes connected by their common edge may also be called "roof". The inclined planes of the weighting elements have a length L in the direction of the longitudinal axis of the pipe and a width I in a plane perpendicular to the longitudinal axis of the pipe. If the distance between the bottom of the pipe and the bottom of the sea is called ground clearance D, and R is the radius of the pipe, the width I of each inclined plane is given by the formula:

I = (R (1 + (1 / sin α / 2)) + D) / cos α / 2 If the inclined planes are connected by a straight edge, the width 1 of each inclined plane will correspond to the preceding formula. On the other hand, if the inclined planes are connected by a rounded edge, the width I of each inclined plane will be slightly different from the theoretical value calculated with a straight edge.

The width I of each inclined plane is therefore a function of the ground clearance D desired.

Preferably, the two inclined planes have a length L between 0 and 10 meters, preferably equal to 1 meter. Preferably, the ground clearance is in the range of 0 to 2 meters, more preferably 1 meter.

Preferably, the radii of the pipe are in the range of less than 0.5 to 5, preferably less than 0.5 to 2 meters.

According to a preferred embodiment of the invention, the width of each inclined plane is 8.24 m for an angle α substantially equal to 90 °.

Preferably the inclined plane consists of a concrete slab or other, as indicated below, having a thickness of at least 3 centimeters. According to the invention, a water pretreatment means is placed at one end of the pipe so as to carry out a degassing of the transported water.

In addition, a system for pumping the water to be transported is used to accelerate the speed of movement of the transported water and relay pumps can be positioned at the bottom of the sea.

The pipe-roof device is completed is completed by a protection and / or weighting at one end or both ends of the pipe to prevent water hammer.

The invention further relates to a method of manufacturing and laying on the seabed of a pipe made of a tube of continuously woven material, characterized in that a circular loom is placed in seam, we weave a portion of said tube, we fix the end of the tube opposite the circular loom on a floating support, we move the floating support to move away from the circular loom by dropping the tube by own weight on the seabed. The woven material is made of a Kelvar® or PBO yarn or other more or less sophisticated material depending on the required toughness as a function of the pressure exerted on the pipe.

The following description, with reference to the accompanying drawings, will provide a better understanding of how the invention can be practiced. The single figure is a cross-sectional view of a hose device according to the present invention.

The device according to the invention comprises a pipe 1 which, in cross section, has a radius R. According to the prior art, this pipe is intended for the transport of liquid, for example water, in a marine environment. More particularly, the pipe is intended for the transport of a liquid whose density is less than 1 kg / m ³ , and therefore less than the density of pure water. This pipe is made of a material continuously woven with synthetic threads. According to the invention, the pipe comprises weighting and anchoring means. Thanks to these weighting means, the pipe does not rise to the surface, while thanks to the anchoring means, which prevent the pipe from having movements at the bottom of the water and therefore avoid its wear by the asperities of the soil such as pebbles, etc.

The pipe 1 is located above the ground 2 so that its lowest point 3 is located at a distance D from the ground 2. The pipe 1 is cylindrical and has an axis passing through the center

C of the base circle of the pipe 1. This axis is substantially rectilinear and parallel substantially to the ground.

According to the invention, the weighting means are constituted by a longitudinal succession, that is to say along the longitudinal axis of the pipe 1 of two series 4, 5 inclined planes connected by their common edge 6.

This common edge 6 can be rectilinear (as represented in 6) or rounded (as shown in 7). A series of inclined planes is such that the inclined plane 4 and the inclined plane 5 together make an angle α. If the edge is rounded, like the edge 7, the inclined planes form in their extension an angle α. In the angle α comes the circle 1 formed by the cross section of the pipe in a plane perpendicular to its longitudinal axis passing through the center C. When the edge joining the planes is rounded, this kind of hinge can be constituted of the same material as the inclined planes if this material is sufficiently flexible, either of another material, such as a canvas or any other. The inclined planes of the weighting elements have a length L in the direction of the longitudinal axis of the pipe and a width I in a plane perpendicular to the longitudinal axis of the pipe. If the distance between the bottom of the pipe and the bottom of the sea is called ground clearance D, and R is the radius of the pipe, the width I of each inclined plane is given by the formula:

I = (R (1 + (1 / sin α / 2)) + D) / cos α / 2

According to a first embodiment of the present invention, if the inclined planes are connected by a straight edge, the width I of each inclined plane will correspond to the preceding formula. On the other hand, if the inclined planes are connected by a rounded edge, the width I of each inclined plane will be slightly different from the theoretical value calculated with a straight edge.

The function mentioned above goes through a minimum for a certain angle at the top which gives the optimal width of the half-planes. The diameters envisaged for the pipe are between 2 and 5 meters. The ground clearance must be between 0 and 2 meters. The following table gives the minimum width of half-planes and the vertex angle for which it is reached.

With pipes approximately four meters in diameter and providing a ground clearance of one meter, a width of 8.24 m is reached for a right angle (90 °). It can be seen that this width moves away from the optimum value by only 33 cm or 4% of the optimum. The right angle has many advantages for the practical realization of these roofs. It is therefore preferred and saves time and cost of manufacture. The material of the inclined planes may be concrete but also polyester or corrugated plate type, or may be a canvas or tarpaulin. If the material of the plates is not of sufficient density to give them the weight necessary for ballasting / anchoring, the plates have additional weights linked to their lower edge. These weights can be parallelepiped blocks. It may be possible to provide plates of a weight greater than that which would be strictly necessary for ballasting / anchoring in order to give them sufficient intrinsic strength (absence of curvature or deflection) and sufficient resistance to external aggression. The inclined planes are attached to the pipe by straps or fastening link to make them integral, for example as shown in 8 in the figure.

During maintenance requiring the recovery of a portion of the pipe to the surface, the inclined planes are raised to the surface by driving the portion of pipe that is integral with them. The inclined planes are connected longitudinally with each other by connecting devices allowing the deflection of an inclined plane relative to the preceding and / or the following.

The method of laying the pipe consists in producing the pipe, attaching it to two inclined planes at least of the fastening link 8, and simultaneously lowering the pipe portion and the inclined planes which are fixed thereto. The inclined planes, by their weight, will cause the pipe to the bottom of the marine environment.

Claims

1. Device for the transport of liquid in a marine environment comprising a pipe (1) consisting of a continuous woven material tube of synthetic threads, characterized in that it comprises weighting and anchoring means constituted by a succession of weighting elements, preferably not contiguous with each other, placed above the pipe (1) and in contact therewith on its upper half, said weighting elements being each constituted by two inclined planes (4 , 5) connected by their common edge (6), rectilinear (6) or rounded (7), so that said inclined planes (4, 5) form an angle α in which the circle formed by the cut of the pipe in a plane perpendicular to its longitudinal axis.

2. Device according to claim 1, characterized in that the inclined planes of the ballast elements have a certain length L

(ranging from 0 to 10 meters) in the direction of the longitudinal axis of the pipe and a width I in a plane perpendicular to the longitudinal axis of the pipe, if the distance between the bottom of the pipe and the bottom of the sea is called ground clearance D, and R is the radius of the pipe, the width I of each inclined plane is given by the formula:

I = (R (1 + (1 / sin α / 2)) + D) / cos α / 2.

3. Device according to any one of the preceding claims, characterized in that the two inclined planes have a length L which can be between 0 and 10 meters, but preferably equal to 1 meter.

4. Device according to any one of the preceding claims, characterized in that the ground clearance D is in the range of 0 to 2 meters, more preferably 1 meter.

5. Device according to any one of the preceding claims, characterized in that the radii of the pipe are in the range of less than 0.5 to 5, preferably less than 0.5 to 2 meters.

6. Device according to any one of the preceding claims, characterized in that the width of each inclined plane is 8.24 m for an angle α substantially equal to 90 °.

7. Device according to any one of the preceding claims, characterized in that the inclined plane consists of a plate having a thickness of at least 3 centimeters.

8. Device according to any one of the preceding claims, characterized in that it comprises a pretreatment means of water at one end of the pipe so as to carry out a degassing of the transported water.

9. Device according to any one of the preceding claims, characterized in that it further comprises a pumping system of the water to be transported to accelerate the speed of movement of the transported water and relay pumps that can be positioned at the bottom of the sea.

10. Device according to any one of the preceding claims, characterized in that it comprises a protection and / or ballast at one end or both ends of the pipe to prevent water hammer.

11. A method of manufacturing and laying on the seabed of a pipe for the device according to any one of the preceding claims, consisting of a continuous woven material tube, characterized in that places a loom Circular sea side, weaving a portion of said tube, the end of the tube is fixed opposite the circular loom on a floating support, moving the floating support to move away from the circular loom.