JPH0223916Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to improvements in fluid transport pipes that transport high-pressure fluids such as oil and natural gas.

PRIOR ART Fluid transport tubes of this type generally have a tube body consisting of an inner plastic layer, an outer plastic layer (sheath), and one or more metal reinforcing layers between these inner and outer plastic layers. . The metal reinforcing layer is formed, for example, by spirally winding a metal strip, so that gas components in the fluid transported by the gas permeation phenomenon in the plastic layer can pass through the inner plastic layer and be transferred between the inner and outer plastic layers. There is a tendency for permeation pressure to accumulate in the space. Although the amount of gas permeation is small, if the permeation pressure reaches a certain high pressure proportional to the internal pressure of the inner plastic layer over a long period of time, the outer plastic layer will be destroyed by this pressure.

In order to prevent this, the outer plastic layer is provided with hole-shaped thin parts at regular intervals in the longitudinal direction, so that when the permeation pressure exceeds a predetermined high pressure, the thin part breaks and absorbs the permeation pressure. A new structure has been proposed. However, with this structure, there was a risk that seawater etc. would enter through the parts where the outer plastic layer was destroyed and corrode the metal reinforcing layer.

It has also been proposed that the outer plastic layer be made of a material with higher transmittance than the inner plastic layer in order to prevent destruction of the outer plastic layer. However, if the material has good permeability, it has low trauma resistance, and it is difficult to select a material that has both properties.

(Purpose of the invention) The purpose of the invention is to provide a fluid transport pipe that can release permeated gas while preventing the intrusion of seawater, etc., and that can appropriately select the material of the outer plastic layer. be.

(Structure of the invention) The fluid transport pipe of the present invention is a fluid transport pipe having a pipe body made of a plurality of plastic layers, which is fluid-tightly attached to the end of the pipe body and permeates into the space between the plurality of plastic layers. It is characterized by having an end portion consisting of an end fitting that receives the permeated gas and a one-way safety valve that is attached to the end fitting and is released when the pressure of the permeated gas exceeds a predetermined value.

According to this structure, when the permeated gas reaches a predetermined high pressure, the safety valve operates and the permeated gas is released, but the safety valve is immediately closed after the permeated gas is released, so seawater etc. do not enter.
Therefore, the metal reinforcing layer will not corrode, and an appropriate material can be selected for the outer plastic layer.

(Embodiment) An embodiment of the present invention will be described in detail with reference to the drawings. The drawing shows a fluid transport pipe 10 according to the present invention,
The fluid transport tube 10 has a plurality of tube bodies, in the illustrated embodiment, two inner and outer plastic layers 12, 14 and two metal reinforcing layers 16, 18 provided between these plastic layers 12, 14. It has 20. The fluid to be transported passes through the inner plastic layer 12 and the outer plastic layer 14
is a sheath. The metal reinforcing layers 16, 18 can be formed by spirally wrapping metal strips.

The fluid transport tube 10 is also fluid-tightly attached to the end of the tube body 20 and has inner and outer plastic layers 12,1.
4, and a one-way safety valve 24 that is attached to the terminal fitting 22 and is released when the pressure of the permeated gas exceeds a predetermined value. ing. The tube body 20 is stripped of the outer plastic layer 14, the metal reinforcing layers 18, 16, and the inner plastic layer 12 in stages at its ends. The terminal fitting 22 is attached to a cup-shaped fitting main body 30 that is liquid-tightly attached to the outer circumference of the end of the outer plastic layer 14 by packing 28, and is attached to the inner plastic layer 12 and the metal reinforcing layer 16 and is screwed into the fitting main body 30. The lid 32 is secured to the inner plastic layer 12 and the metal reinforcing layer 16 by a compound 34. The safety valve 24 consists of a valve seat 35 that is screwed into the metal fitting body 30 in a fluid-tight manner and a valve rod 38 that passes through the valve seat and is normally in close contact with the valve seat 35 by a spring 36.

Next, the operation of the fluid transport pipe 10 of the present invention will be described. Normally, the safety valve 24 is closed by the spring 36 as shown in the figure. Internal plastic layer 1
Gas components in the fluid passing through the inner and outer plastic layers 12, 1 permeate through the inner plastic layer 12.
When the pressure of this permeated gas increases to a predetermined pressure, for example, 1 kg/cm ² or more, the spring 36 is tightened and the valve rod 38 of the safety valve 24 is closed. Push up and permeate gas is released. When the pressure of the permeate gas in the space 21 falls in this way, the valve rod 38 is pressed down by the spring 36 and the safety valve 24 is closed.

(Effects of the invention) According to the invention, as described above, the permeable gas accumulated between the inner and outer plastic layers is released from the check-type safety valve attached to the terminal fitting, thereby destroying the outer plastic layer. Without a problem,
In addition, since the safety valve is immediately closed after the permeated gas is released, seawater etc. do not enter and corrode the metal reinforcing layer. Furthermore, the material of the outer plastic layer can be selected appropriately, making it economical. It is true.

[Brief explanation of the drawing]

The drawing is a sectional view of the end portion of the fluid transport pipe according to the present invention. DESCRIPTION OF SYMBOLS 10...Fluid transport pipe, 12, 14...Plastic layer, 20...Pipe body, 22...Terminal fitting, 2
4... Safety valve, 26... Terminal section.

Claims (1)

[Scope of utility model registration request] In a fluid transport pipe having a pipe body made of a plurality of plastic layers, an end fitting is attached to an end of the pipe body in a liquid-tight manner and receives a permeate gas that permeates into a space between the plurality of plastic layers; 1. A fluid transport pipe, characterized in that it is equipped with an end portion comprising a one-way safety valve attached thereto and released when the pressure of the permeated gas exceeds a predetermined value.