JPH061661Y2 - Tail swing type fairing ring with protective tube as fixed head - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to various kinds of equipment such as a pressure oil pipe, a compressed air pipe, a power cable, etc. for operating a transportation pipe extended in water and various equipments located on the seabed. The present invention relates to a fairing for surrounding the outer circumference of tubing to reduce resistance caused by water flow.

[Conventional technology]

In recent years, when collecting manganese nodules existing on the sea floor, 500 pipes or cables (hereinafter simply referred to as pipes) connected to devices such as an air compressor and a power source mounted on a work boat are used.
The manganese nodules are sucked down as if they were sucked with a vacuum cleaner, while being lowered into 0 m of water and towing a sampling device provided at the tip of the pipes by a work boat to move on the seabed. Compressed air is supplied into the pipe and is transferred to the work boat by the action of the bubble pump.

As a problem of the work of recovering the manganese nodules, it is necessary to keep a large number of pipes having a length of 5000 m or more from the work boat to the sampling device in a disjointed state, in addition to the entanglement or cutting of the pipes It causes a great resistance.

For example, there are 5 tidal currents in the sea area where manganese nodules are collected.
There are ~ 7 knots, and the speed at which the work vessel travels while collecting manganese nodules is 3-5 knots or more, so the relative water flow acting on the pipes becomes 3-10 knots, Along with this water flow, a great resistance is generated in the pipes.

Since the resistance generated when towing the tubing and the sampling device increases the power required for propulsion of the work boat, it is necessary to reduce this resistance as much as possible.

On the other hand, when a water flow acts on the pipes, Karman vortices are generated alternately behind and disappear, but the frequency of these Karman vortices coincides with the natural period related to the length and weight of the pipes. This may cause the tubing to resonate and eventually be damaged.

Further, as another example, problems such as vortex generation and vibration due to tidal current also occur in pipes such as a transport pipe connecting an offshore workbench and an offshore oilfield in oil drilling of an offshore oilfield.

By the way, as a means for extinguishing or reducing the Karman vortex generated behind the tubing, a method of surrounding the tubing with a fairing having a wing-shaped cross section is proposed in Japanese Patent Laid-Open No. 53-64394.

A conventional fairing is configured such that various tubes and cables are wrapped in a sliding surface of a bearing, and the fairing is swung on the sliding surface.

On the other hand, the resistance to flow is received by the entire projected area of the fairing, but the conventional fairing has a structure in which the sliding surface of the bearing is further covered with the skeleton of the fairing. However, there is a drawback that the total projected area increases and the resistance to the flow becomes considerably large.

This means that the load acting on the bearing and the load acting on the pipes increase, which has been an obstacle to improving the followability to the flow of the fairing.

Furthermore, the tubing was exposed in the area where the fairing was not attached, and the effect of flow was complicated.

In addition, since the conventional fairing, which is divided into two parts in the longitudinal direction on the left and right sides, has a structure that is essentially deformable,
The fairing body requires high rigidity, which causes an increase in weight and projected area.

Further, the conventional fairing has a problem that it is difficult to easily attach it to the pipes because it has a two-part structure.

[Purpose of device]

The present invention has been made to solve the above-mentioned problems of the prior art. The purpose of the present invention is to reduce the flow resistance, that is, to reduce the total projected area. To provide.

The purpose of the present invention is to provide a fairing that has a simple structure and is lightweight, but has relatively high strength.

It is to provide a fairing that is easy to put on and take off and has excellent turning performance.

[Outline of device]

In order to achieve the above object, the present invention fixes a protection tube provided with a fairing main body having a streamlined side surface to a protection tube provided outside the tubing through a rotatable band body. It is a tail turning type fairing with a head.

The conventional effering is composed of a high-rigidity fairing head that further surrounds the bearing sliding surface and a fairing tail that generates a swirling force along with the flow and smoothes the flow. By omitting the fairing head and allowing the fairing tail to directly swivel with respect to the protection tube, the fairing tail alone provides a function similar to that of a conventional fairing having a complicated structure. It is characterized by this.

The tail swirl type fairing in which the protective tube according to the present invention is fixed is a box-shaped fairing tube that surrounds a plurality of tubes and has a streamlined side surface and a width gradually reduced downstream. The fairing main body and a connecting body for pivotally connecting the fairing main body to the protection tube are used, and the connecting body uses a band body in the embodiment. It is provided so that it can hold a protection tube and slide on it.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of a tail swivel type fairing F having a fixed head of a protective tube according to the present invention, and FIG. 2 is a front view thereof.

The fairing F is composed of a fairing body 1 and a connecting body, that is, a band body 2 provided on the front surface of the fairing body 1, and a pipe 3
The band body 2 is rotated around the protective tube 4 surrounding the above and the band body 2 is slid on the protective tube 4 so that the band body 2 can be swung.

The fairing body 1 is reinforced by arranging partition walls 6 and horizontal ribs 7 vertically and horizontally in an outer skin 5 which is streamlined on both sides and whose width is gradually reduced toward the downstream side.
Further, a pillar 8 having an inner surface formed on a curved surface matching the curved surface of the protection tube 4, a pillar 9 for fixing the lateral ribs 7 and the like, and a horizontal rail 10 are provided at the front portion of the fairing main body 1. The end of the band body 2 is fixed to the reinforced portion. The upper and lower surfaces of the fairing body 1 are preferably opened to balance the pressure inside and outside.

Since the force due to the fluid resistance acting on the fairing body 1 acts on the portion of the protective tube 4 surrounding the pipes such as the transport pipe, the compressed air pipe, the pressure oil pipe, and the cable, to which the band body 2 is attached, the reinforcement is reinforced. It is better to have been.

Two split rings 11a and 11b are provided above and below the protection tube 4 to maintain the mutual positional relationship of the tubes 3 and to protect the protection tube 4 from each other.
Are reinforced.

Further, on the side surfaces of the split rings 11a and 11b, a movement preventing ring 12 is formed in a flange shape so as to come into contact with the end surface of the protection tube 4 in order to prevent the fairing body 1 from moving up and down. ing.

In this embodiment, the surface of the protective tube 4 on which the band body 2 that is a connecting body is located is not particularly formed with a surface for supporting and sliding the band body 2, but for supporting the band body 2, You may form the surface (bearing surface) which can be moved lightly.

[Effect of device]

The tail swivel type fairing with the protection tube of the present invention as a fixed head is a fairing tail that is a part of the conventional fairing by protecting the circumference of tubing consisting of multiple tubes and cables with a protection tube. It is characterized in that the fairing body corresponding to the above is pivotally connected to the protection tube via a band body, and the following effects can be obtained.

(1) Since the conventional fairing has a structure in which the head is omitted, the width of the front surface of the fairing body in the present invention may be substantially the same as the width of the protective tube for protecting the tubing. Therefore, it is possible to reduce the thickness of at least the ribs of the conventional fairing, thereby reducing the total projected area by that amount, and reducing the flow resistance.

Since the resistance to flow decreases, the force of the work boat when towing pipes decreases, the propulsive force of the work boat decreases, and the power required for towing work decreases. .

(2) Since the projected area of the fairing body is reduced, the load on the friction surface between the protective tube and the band portion of the fairing body is significantly reduced, and the fairing body is rotated with a small turning force. You can

(3) Since it is composed of the fairing main body using only the tail portion of the conventional fairing, it is lightweight and advantageous in terms of strength.

In the conventional fairing, it is divided into two parts, but the fairing body according to the present invention has a light structure in which the opening / closing mechanism is omitted because it is an integral structure, and the length of the fairing body is easy. Since the length can be made extremely long, a large [blade thickness-chord length ratio] can be obtained, the swirling force can be increased, and the resistance to the flow can be reduced.

(4) Assembling is completed only by connecting the fairing main body via the band body so that the fairing main body can be swung. Therefore, the attachment / detachment operation is easy and the workability is excellent.

(5) Especially by using the fairing according to the present invention for the pipes used for collecting manganese nodules,
Since the fluid resistance acting on the pipes is significantly reduced and the pipes and the sampling device can be towed with a small amount of power, the manganese nodules can be efficiently collected by a small work boat.

(6) Since the fairing according to the present invention can prevent the Karman vortex from being generated behind the pipes, there is no risk of damaging the pipes.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of a tail swivel type fairing using a protective tube of the present invention as a fixed head, and FIG. 2 is a side view of the same. F ... Fairing, 1 ... Fairing body, 2 ... Band body, 3 ... Tubes, 4 ... Protection tube, 5 ... Outer skin, 6 ... Partition wall, 7 ... Lateral ribs, 8 ... Protection tube, fairing body adhesion column , 9 ... pillars, 10 ... horizontal rails, 11a, 11b ... split ring, 12 ... movement prevention ring.

Claims (1)

[Scope of utility model registration request] 1. A protection tube provided with a protection tube which covers the outside of tubing and a fairing body of integral structure having a streamlined side surface through a rotatable band body. A tail turning type fairing with a fixed head.