JPS586107B2 - watermelon - Google Patents

Description

Detailed Description of the Invention This invention covers the outer periphery of water pipes such as iron pipes with a material of extremely light specific gravity such as foam to give them buoyancy in water, especially in the sea, and to provide water pipes such as steel cables fixed to the seabed. This invention relates to a water transmission pipe used in an underwater water transmission system that extends into the sea at a certain depth while being supported by a balance between buoyancy and mooring force. By easily and inexpensively connecting the area and the supply area with fresh water pipes, water problems can be solved at once.

In other words, until now, water transmission lines between freshwater demand areas and supply areas have mostly been made of iron pipes or pipes lined with concrete. As a general rule, they are buried underground, and there is always a grade-separated intersection with everything above ground.

Therefore, from the perspective of a main water supply line, this kind of underground construction can be said to be a structure that almost satisfies our needs, but it is also difficult to withstand sufficient ground pressure and internal water pressure, and from earthquake resistance considerations. It is necessary to use thick pipes, and on top of that, the cost of underground construction is high, especially when it comes to laying ultra-large diameter pipes used for water supply canals from water source areas to demand areas, and the cost is enormous, especially in urban areas. As we get closer, obstacles from aboveground and underground topographical features become more serious, which has a significant impact on construction techniques and costs.

On the other hand, in the case of a relationship between a water demand area and a water supply source area that are separated by the sea, water supply by constructing underwater or undersea water pipes to connect these areas has not been widely used to date.

However, although oil pipe lines installed on the sea surface or the seabed for the transportation of oil and gas have been well researched and are widely used around the world, it is difficult to apply this technology to transport freshwater underwater. Although possible, the final form of pipe laying that forms the basis of these technologies is usually an extended length of pipe laid on the ground on the ocean floor, but it is necessary to compensate for some degree of topographical change. An immersion method, in which the pipes are partially buried by excavating the seabed, is also being adopted.

However, in cases where the topography changes drastically, or when using a special installation ship that welds and connects single pipes on board and sinks them to the seabed, especially when laying ultra-large diameter pipes on the seabed that cannot have a large radius of curvature. Naturally, it would be difficult to match the topography of the seabed, so it would be necessary to use a method of immersion by digging, and a type of underwater bridge would be used to cross the submarine canyon, which would not only increase construction costs considerably, but It becomes difficult to move the work boat forward while hanging down the welded long pipes.

In addition, when constructing a water transmission line in an extremely deep part of the seabed, there may be few problems if the line is simply sunk into the seabed, but various problems may occur when burying it using divers or work boats and maintaining it. It's coming.

In other words, when laying pipes on the seabed in deep seas, if the pipes are in close contact with the deep seabed, it becomes difficult for divers to inspect and repair the pipes due to diving disease, and on the seabed where sludge has accumulated, it is difficult to confirm the existence of the pipes themselves. It becomes difficult.

Therefore, as part of the present invention, we have developed a system in which water pipes with a structure that has a specific gravity slightly lower than that of seawater are connected while floating on the sea surface, and the long water pipes formed in this way are submerged evenly into the sea, so that the entire length of the pipes is connected to the sea surface. By stopping and fixing at a certain depth below, a water supply system line using thin-walled, ultra-large diameter pipes can be constructed easily and inexpensively, making full use of divers and work boats. The purpose of the present invention is to provide a subsea water pipe suitable for constructing a new freshwater subsea water transmission facility that does not pose special difficulties in maintenance and management, since it can be installed at a convenient depth.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, the present invention will be described in detail with reference to the drawings, its structure and embodiments using the same.

The underwater water pipe 1 consists of a steel pipe 2 whose inner and outer surfaces are lined with mortar, plastic, etc.
Foam material 3 made of hard plastic or the like having closed cells
The structure is such that the outer surface of the soft foam 3 is covered with a protective outer cover 4 made of a thin plate for protecting the soft foam 3.

In this case, the thickness of the foam 3 is such that the specific gravity of the entire tube 1 is lower than the seawater so that the tube 1 will slightly appear above the water surface 5 when placed in seawater, as illustrated in FIG. Made to be slightly lighter.

When a large number of such underwater water pipes 1 are connected and floated on the sea surface, for example, by mechanical joints, as shown in FIG. 8 and then tighten the form metal 9 with bolts 10 to join the two pipes 1.

In addition, since the area near the joint between the two pipes 2 and 2 cannot be covered with the foam 3 and the protective jacket 4, heat-shrinkable plastic or corrosion-resistant material is required to prevent corrosion from seawater and to protect both ends of the foam 30. A protective film 11 made of a metal plate or the like is applied.

4 Furthermore, in the case of joining by electric welding, the above-mentioned joining mechanism is omitted and the welding of the contact surfaces of the two pipes 2 and 2 is simply performed while floating on the sea surface, but in this case, the welding is done evenly over the entire pipe. Give auxiliary buoyancy to float the tubes 1 and 1 on the water surface.
Welding is carried out on the floating part while rotating.

When the long underwater water pipe 1 connected in this way is connected by a mechanical joint, a lifting rope 13 to which a floating box 12 is attached is fitted in one of the two grooves provided in a part of the form metal 9. Insert the tethering rope 15 with the weight 14 attached to the other grooves, and hold the spring-like presser metal fitting 16 over these grooves so that the claws at both ends of the metal fitting 16 catch on the protrusion of the form metal 9 and do not come off. Cover both ropes 13.15
hold down.

In addition, for those joined by welding, the welded portion is covered with a protective film 11 etc. in accordance with the above, and a metal mold etc. having lobe grooves is similarly fitted thereon to attach the rope 13.15.

After the underwater water pipe 1 is in this state, it is released into the sea. In this case, the floating box 12 has a floating body 17 made of a material such as hard foam at the lower part of the inside of the box 12, as shown in FIG. It is mounted so that it can slide upwards inside the floating box 12 like a piston, and the inside of the floating box 12 above the floating body 17 is a large air chamber 18, giving a large buoyancy to the entire volume of the floating box 12. Therefore, when the tube 1 is released into the sea, the buoyant force of the floating box 12 is added to the buoyant force of the tube 1 itself against the settling weight 14 attached to it, and the buoyant force slightly overcomes the force that tries to sink. The floating box 12 does not sink, but floats near the sea surface as shown in FIG. 2 while being lifted up by a lifting rope 13 hooked onto a retaining ring 20 at the lower end of a shaft 19 passing through the interior of the floating box 12.

The construction work will be carried out by selecting a season when the waves are calm and there are few strong winds.
After the long tube 1 connected in this way is floated near the sea surface, the explosive plugs 22 loaded with gunpowder 21 screwed into the upper part of each floating box 12 are exposed to many objects from the outside via electric wires. All of them are energized and ignited all at once, causing an explosion.

When the upper lid of the explosion plug 22 is blown off by this explosion, the air in the air chamber 18 is forced to the outside, and the force of the weight of the weight 14 to pull it into the sea is applied to the floating body 11. The floating box 12 is pushed upwardly from below, so that the air in the air chamber 18 is expelled.

As a result, the buoyancy corresponding to the displaced air capacity is lost, so the underwater water pipe 1 slowly sinks and reaches the seabed 23 as shown in FIG. 3.

However, inside the floating box 12, air that is not removed by the water pressure is still stored therein as a foam that constitutes the floating body 17, and the floating box 12 still has a considerable buoyancy, so there is a weight on the seabed 23. 14 reaches the bottom, tube 1 is on the seabed 23
It is moored in the nearby sea via a rope 15 as shown in Figure 4.

In this case, by adjusting the length of the mooring rope 15 according to the topography of the seabed 23 that has been surveyed in advance, it is possible to run the piping straight to a certain depth underwater without being affected by the topography of the seabed 23. Therefore, it is extremely advantageous for installing ultra-large diameter pipes that cannot have a large radius of curvature.

Next, a straight pile made of reinforced concrete is driven into the seabed 23 using an underwater work vessel or the like, or a spiral pile made of concrete 24 is driven into the seabed 23.
or by dropping concrete blocks for permanent mooring as full-scale weights, replacing the mooring lobes 15 with these, and constructing the underwater water pipe as shown in Figures 5 and 9. complete.

A settling weight 14 used for settling and temporarily mooring the pipe 1 is used by putting sand and gravel in a large packet, and only the sand and gravel are disposed of on the seabed 23 after use.

Finally, fresh water is sent from one of the water pipes 1, 1, . . . to push out and replace the seawater that had been in the pipe from the beginning to the outlet of the other pipe, and fresh water is then continuously fed.

The underwater water pipe line constructed in this way is supported by seawater without applying excessive force to the huge large-diameter pipe due to the small buoyancy of the pipe itself, so the floating box 12 The buoyant force is simply to tension the mooring ropes 15 from the seabed 23 to keep the pipe 1 at a constant depth and prevent it from swaying, so the mooring ropes 15 can be spaced sufficiently apart. Since the number of mooring points can be kept to a minimum, construction costs can be significantly reduced.

Furthermore, considering that not only fixed piping and buried pipes on land but also submerged pipes on the seabed are the most vulnerable to earthquakes and ground movements, piping at a certain depth according to the present invention is extremely safe and Since the pipes are installed at a certain depth below, there is no need to worry about damage from waves caused by typhoons.

Also, at first glance, it appears to be vulnerable to tidal currents, but once the rope is stretched into a triangular structure and fixed to the seabed in earnest, the tube body will hardly sway unless it is in a place where there are particularly strong tidal currents. There isn't.

Furthermore, as the depth of underwater water pipes increases, the internal water pressure increases, and at the same time, the external seawater pressure also increases, and the difference in internal and external water pressure can be maintained evenly over the entire length, so the internal water pressure can be specially controlled. Costs can also be kept low in this respect since the tube walls can be made very thin without being too high.

In other words, if a large diameter pipe is used to send a large amount of water at low speed and low pressure, it is possible to use ultra-large diameter pipes, which are inexpensive, thin-walled pipes that cannot be used on land, and therefore the flow velocity is slow. There is more than enough to compensate for this.

In this respect, land-based piping is limited by the diameter of the pipe, so a high-speed, high-pressure water supply method with a small amount of water must be used.

This requires the use of strong, thick-walled iron pipes, etc., and a special water-tight connection, and even the slightest water leakage causes great damage to the surrounding area.

However, in the case of the present invention, water is conveyed at low speed and low pressure.
It is possible to join pipes using a simpler joining method than the method exemplified here, and even if a small amount of water leaks in some places, it will not cause damage to others because it is in seawater. Also, there is no risk that seawater will flow back into the pipe and mix into freshwater.

In addition to the embodiments described here, the water conveying device using underwater water pipes of the present invention can also be used to transport clean fresh water through freshwater such as lake water, and can also be used to transport seawater in polluted sea areas to the open ocean. It can also be used to transport clean seawater.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the underwater water supply pipe of this invention floating alone on the water surface, and Figure 2 is a cross-sectional view of the underwater water supply pipe of this invention when it is floating alone on the water surface. Figure 3 is a cross-sectional view of the floating box with the box attached and floating near the sea surface, Figure 3 is a cross-sectional view of the floating box with the buoyancy reduced and it sinks to the seabed following Figure 2, Figure 4 is Figure 3 Figure 5 is a cross-sectional view of the state in which the helical pile for mooring is screwed into the seabed, and Figure 5 is a cross-sectional view of the state in which the weight has been removed and the mooring rope has been replaced with the helical pile.
Figure 6 is a longitudinal sectional view with some parts missing showing an example of the joint of an underwater water supply pipe, Figure 7 is a longitudinal sectional view of the floating box, and Figure 8 is a vertical sectional view of the explosion plug that is part of the floating box. FIG. 9 is a longitudinal cross-sectional view showing a portion of the present invention, and FIG. 9 is a perspective view showing an embodiment in which an underwater pipeline is constructed using the underwater water pipe according to the present invention.

Claims (1)

[Claims] 1 The outer surface of iron pipes, etc. is covered with closed-cell hard foam, etc., and the outer surface is further covered with a hard protective plate.It has a thin wall with an extremely large diameter, and has a specific gravity slightly lighter than that of non-flexible seawater. Undersea water pipes.