JPH0357360B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a vibration isolating device for an underwater pipe that prevents an underwater working pipe suspended from an offshore workbench from vibrating under the influence of water flow. It is related to.

<Prior Art> In underwater drilling work, a Karman vortex may be generated when an underwater work pipe suspended from an offshore workbench is placed in a water flow.

The generation of this Karman vortex causes the underwater pipe to vibrate, which causes a decrease in the durability of the underwater pipe.

Therefore, as a method for preventing the vibration of the underwater pipe, a certain degree of effectiveness has conventionally been achieved by attaching a long, flexible flag body along the underwater pipe.

<Problems to be Solved by the Present Invention> The conventional underwater pipe vibration isolation technology described above has the following problems.

That is, since conventionally a single long flag was used, the flag did not follow the flow smoothly in complex areas where the water flow was very fast.

Therefore, the anti-vibration effect is halved.

Furthermore, due to the large resistance to water flow, flag bodies and other structures are severely damaged, making it extremely difficult to repair only the damaged parts.

<Objective of the present invention> The present invention was made to solve the above-mentioned problems, and it effectively prevents vibrations of underwater pipes caused by Karman vortices, etc., and improves durability and repairability. The purpose of the present invention is to provide a vibration isolating device for underwater pipes that can improve the vibration of underwater pipes.

<Structure of the present invention> An embodiment of the present invention will be described below with reference to the drawings.

<A> Ring body (Figs. 1 and 3) The ring body 1 is inserted into an underwater pipe 6 for work hanging from a workbench at sea, etc., and suspended by a wire rope 4 in the middle of the underwater pipe 6. It is a divisible ring.

This ring body 1 is formed to have a slightly larger diameter than the underwater pipe 6, and can rotate without contacting the underwater pipe 6.

Further, since the ring body 1 is configured to be divisible by cutting off the connecting portion 11, the ring body 1 can be attached from any intermediate position without having to be inserted from the upper end of the underwater pipe 6.

<B> Wire Rope (Fig. 1) The wire rope 4 is a rope on which the ring body 1 is suspended from a workbench 7 on the ocean.

For example, the workbench 7 near the top of the underwater pipe 6
Two pulleys 41 are provided at opposing positions, and the wire rope 4 is hooked to the pulleys 41 and suspended, the lower end of the wire rope 4 is connected to the ring body 1, and the upper end is provided with a chill hole 4.
2, etc., to raise and lower the ring body 1 and the flag group.

When the ring body 1 is suspended, the ring body 1 is positioned horizontally and suspended from the underwater pipe 6 at equal intervals.

In short, as will be described later, it is sufficient if the ring body 1 can be suspended rotatably in the circumferential direction of the underwater pipe 6.

<C> Flag body (Figure 3) The present invention does not use a single long flag body as in the past, but is constructed using a plurality of small pieces of flag bodies.

The flag body consists of a steel flag body 2 made of a rigid steel plate or the like, and a cloth flag body 3 made of a flexible cloth body or the like.

As shown in FIG. 3, the steel flag body 2 is constructed by attaching a steel plate to a formwork 21 assembled into a predetermined shape.

The cloth flag body 3 is made by attaching cloth to a formwork 31 in the same way.

Since the steel flag body 2 and the cloth flag body 3 are subject to large resistance from water flow, they are constructed to be strong by attaching reinforcing materials or the like.

<d> Attaching the flag body (Fig. 3) First, a plurality of chains 5 are connected and suspended from the bottom surface of the ring body 1.

A steel flag body 2 is attached to the top of this chain 5, and a predetermined number of cloth flag bodies 3 are attached below it.

When installing, install flag body 2 and formwork 2 in advance.
1 and each flag body 3 and formwork 31 are assembled and connected by a chain 5 and a shackle 51 or the like.

Each chain 5 is connected to a plurality of flag retaining rings 52 fitted into the underwater pipe 6 to prevent the flag body from drifting away from the underwater pipe 6.

The flag retaining ring 52 is configured to be splittable like the ring body 1, so that it can be attached from the middle of the underwater pipe 6.

An auxiliary chain 22 is attached to the steel flag body 2 from the ring body 1 like a hand steel so that it can easily follow the flow.

<Action of the present invention> The action of the underwater pipe vibration isolator constructed as described above is as follows.

In Figure 1, the water flow is directed in the direction of the arrow, and the flag group is located on the downstream side.

When the direction of the water current changes and flows from the opposite side as shown in Figure 2, the flag group receives resistance from the water flow, the wire rope 4 twists along the underwater pipe 6, and the ring body 1 The flag group rotates, and the flag group smoothly follows the water flow and reverses itself.

When the water flow returns to its original direction, the wire rope 4 is untwisted by the weight of the flag group, allowing the flag group to return to its original position.

By suspending the flag group with the wire rope 4 in this manner and utilizing the twisting force of the wire rope 4, the flag group can be made to smoothly follow the water flow.

Also, some cause (for example, algae, etc.) may cause ring body 1.
Even if the ring body 1 is in a state where it is difficult to rotate, the rigid steel flag body 2 is subjected to large resistance from the water current, so it acts as a rudder for the ship and the ring body 1 is in a state where it is difficult to rotate. The flag body 1 can be turned to smoothly move the flag group downstream.

The flags moved downstream are separated from each other, allowing them to swing freely independently.

Therefore, Karman vortices and the like can be disturbed and effectively dissipated.

<Effects of the Present Invention> Since the present invention has been described above, the following effects can be expected.

<B> Previously, a long single flag was used as a vibration isolator for underwater pipes, so the water flow was extremely fast.
In complex areas, the flag did not follow the flow smoothly, reducing the anti-vibration effect by half.

In contrast, in the present invention, a small flag group is suspended by a wire rope, and by utilizing the twist of the wire rope, the flag group is rotatably attached around an underwater pipe.

Therefore, the flag group can smoothly follow the water flow, and the vibration isolation effect can be improved.

<B> Attach a rigid steel flag body to the top of the flag group.

This steel flag body receives a large amount of resistance from water flow, so it acts as a ship's rudder and allows the ring body to turn.

Therefore, the flag group can be made to follow the water flow smoothly, and the vibration isolation effect can be improved.

<C> The present invention has a simple structure in which a group of flag bodies of small pieces are attached to be rotatable by wire ropes.

Therefore, the manufacturing cost is low and it is economical.

<D> Each flag body is separate, so
They are now able to move independently and freely.

Therefore, Karman vortices and the like can be disturbed and effectively dissipated.

<E> Even if the ring body is difficult to rotate due to some reason (for example, if algae gets caught on the ring body), the ring body can be rotated by the steel flag body. .

Therefore, movement of the flag group is not hindered.

＜F＞ Conventional large single flag bodies are subject to significant damage due to the large resistance to water flow, making it extremely difficult to repair only the damaged parts.

Therefore, if the flag is damaged, the entire flag must be replaced, which is time-consuming and requires relatively high material costs.

However, in the present invention, a group of flags is composed of independent small pieces of flags.

Therefore, each flag body experiences little resistance from water flow and is less likely to be damaged.

In addition, even if the flag is damaged, only the damaged part of the flag needs to be replaced, and since it is a small piece, replacement is easy and the material cost is low.

<G> Even if the flag group becomes weak due to strong currents making it impossible to replace parts, or when there is a shortage of spare parts for the equipment, it is unlikely that the anti-vibration effect will be completely lost. do not have.

Furthermore, in the event that the group of flags is missing, the worst situation can at least be avoided by changing the mounting position of the flags to a position that is effective for vibration isolation.

<H> Conventionally, the flag bodies were connected using wire ropes, but the water flow caused slight vibrations that caused the wires to break, resulting in durability problems.

The present invention uses chains to connect the flag bodies, so durability is improved.

Furthermore, since the flag body can be easily attached to the chain with a shackle or the like, damaged areas can be easily repaired.

[Brief explanation of drawings]

Figure 1: An explanatory diagram of an embodiment of the present invention, Figure 2:
An explanatory diagram showing a twisted state of the wire rope. FIG. 3: An explanatory diagram showing a state in which the flag body is attached.

Claims (1)

[Scope of Claims] 1. A group of plates installed along a pipe suspended in water, including a top plate made of a rigid member and other lower plates made of flexible members. A vibration isolating device for underwater pipes consisting of a wire rope that suspends a group of plates in the middle of the pipe so that they can rotate.