Pipe connection mechanism, pipe connection method, and pipe connection device

Abstract

To maintain connection of a pipe against a total weight when the pipe is connected on a ship.SOLUTION: A pipe connection mechanism of a long pipe has: plural pipe 30, 34; and a connection pipe 32 covering an outer face of a portion including one end of each pipe, and fixed to the outer face of each pipe to extend from the end of each pipe. A minimum inside diameter portion of the connection pipe has inside diameter dimension smaller than an outside diameter of a pipe to be connected in a temperature range of -80°C to 50°C. The inside diameter dimension is set so that the inside diameter dimension becomes larger than outside diameter of the pipe to be connected and the pipe to be connected is fitted with the connection pipe, by heating and thermally expanding the minimum inside diameter portion of the connection pipe in a temperature range higher than 50°C and 450°C or lower. A refined martensite steel, an austenite-base stainless steel, or an austenite-ferrite base stainless steel is used for the connection pipe.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention is a method for connecting a plurality of pipes to a water surface or a water bottom. Pipe connection mechanism for connecting long pipes between pipes, pipe connection method, and pipe connection device for connecting pipes - Patents.com Regarding. [Background technology]

[0002] To efficiently pull heavy oil, which is slightly lighter than seawater, from offshore oil fields that lack natural flow pressure. In this technology, the riser is used to lift the gas. By injecting a gas with a relatively small mass into the liquid inside the tube, The liquid column pressure in the pipe is reduced by the volume ratio, and the riser pipe is The pressure of the external seawater and the oil layer creates a pushing force, and the rising force of the air bubbles is used to create the The specified target material is brought to the surface. Mud containing rare earths and other substances stored on the seabed, Even for heavy minerals, for example, they can be crushed into small pieces and mixed with seawater to make a slurry. It is believed that the above-mentioned air bubble lift technology can be effectively used from deep seas, such as 6,000 m below the seabed.

[0003] The riser pipe used in the above-mentioned bubble lift technology is approximately linear from the sea surface to the seabed several thousand meters below. This type of piping is installed on a ship and Above, it is necessary to connect these pipes to create a riser pipe. In the conventional method of connecting pipes to create a riser pipe, A thread is formed on the outer surface of one of the pipes and the inner surface of the other pipe, and the thread on the outer surface and the thread on the inner surface are connected to each other. On the other hand, the cable that extends from the sea surface to the bottom several thousand meters is The number of pipes in the riser pipe is very large, and the total weight of the riser pipe is very large. The riser pipe is subjected to buoyancy at the sea surface, which acts on the joint between the pipes near the sea surface at the top of the riser pipe. Although the resultant vertical force, i.e., the tensile load, is reduced compared to the total weight, the resultant force is Since the force is very large, the thickness of the pipes is thinned and the lath is thinned, taking into consideration the mechanical strength of the pipe joints. The resultant vertical force on the upper part of the riser pipe must be reduced. In the above connection method, in which a large vertical thread is provided on the threaded portion of the pipe on the sea surface side, In addition, the riser pipe is subject to large lateral forces due to ocean currents, etc. As a result, the thinned pipe threads may not be able to withstand the combined force and may be damaged. There is a match.

[0004] Meanwhile, the following technique is known regarding a method for connecting tubular metal members (Patent Document 1). In this technique, a concentric small diameter pipe member and a flange portion which is a large diameter pipe member are prepared. The inside diameter of the large flange is equal to or slightly smaller than the outside diameter of the small pipe. A temperature difference is created between the small diameter tube and the small diameter tube, and the thermal expansion caused by this temperature difference is used to expand the large diameter tube. The inner diameter of the hole in the flange is made larger than the outer diameter of the small diameter pipe member, and the pipes are connected by fitting together. In other words, this technology is a shrink fitting technology. Instead of connecting them directly, the pipes are inserted into the holes in the flanges and fitted together. As a result, the pipes are indirectly connected to each other via the flange portion (see Figures 1 to 3 of Patent Document 1). ). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2009 / 077735 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above technology, which connects pipes together via flanges, is used at depths several thousand meters below the sea surface. When applied to a riser pipe extending to the top of a pipe, a pipe is connected to the riser pipe to connect the pipes. The total weight of the riser pipe is very large because the flanges are connected by bolts, etc. In particular, when multiple pipes are connected to each other, Long pipes extending between the sea and the sea, especially pipes extending vertically for more than 3000m at great depths In order to ensure the mechanical strength of the riser pipe, the pipe thickness is increased, and the total weight becomes very large. In response to this, a buoyant body is installed around the riser pipe body, The total weight of the riser pipe can be reduced, but when a buoyant body is installed, the mass of the buoyant body itself is also added, Since the total mass of the riser pipe and the buoyant body becomes large, the tensile load acting on the riser pipe is larger than that of the buoyant body. This cannot be mitigated due to the inertial force caused by the motion. It becomes difficult to suspend the riser pipe from a force body, ship, etc.

[0007] Therefore, the present invention is a method for connecting a plurality of pipes to the bottom of the water or the ground below the bottom of the water, The mechanical strength of the piping can be secured against the tensile load of the long pipe extending between the water surface and the piping. The present invention aims to provide a pipe connection mechanism, a pipe connection method, and a pipe connection device for connecting pipes. The target. [Means for solving the problem]

[0008] In one aspect of the present invention, a plurality of pipes are connected to the bottom of the water or the ground below the bottom of the water, This is a piping connection mechanism for a long pipe that is extended between the water surface and the water. Multiple pipes and Each pipe is provided with a pipe cover on its outer surface including one end thereof and extending from said end. and a connecting pipe having a minimum inner diameter portion fixed to the outer surface of the piping. The minimum inner diameter portion of the connecting pipe is designed to be connected at a temperature range of -80°C to 50°C. The inside diameter is smaller than the outside diameter of the pipe to be used, and the temperature range is 50°C to 450°C. The inside diameter of the connecting pipe is increased by heating the smallest inside diameter portion of the connecting pipe in the vicinity of the connecting pipe and thermally expanding the smallest inside diameter portion of the connecting pipe. The outer diameter of the pipe to be connected is larger than that of the pipe to be connected. The inner diameter is set so as to be able to fit onto the connecting pipe. The connecting pipe is made of tempered martensitic steel, austenitic stainless steel, or Austenitic and ferritic stainless steels are used.

[0009] In another embodiment of the present invention, a plurality of pipes are connected to each other to connect the water bottom or the underground below the water bottom. and a piping connection mechanism for a long pipe that extends between the water surface and the water tank. Multiple pipes and Each pipe is provided with a pipe cover on its outer surface including one end thereof and extending from said end. and a connecting pipe having a minimum inner diameter portion fixed to the outer surface of the piping. The minimum inner diameter portion of the connecting pipe is designed to be connected at a temperature range of -80°C to 50°C. The inside diameter is smaller than the outside diameter of the pipe to be used, and the temperature range is 50°C to 450°C. The inside diameter of the connecting pipe is increased by heating the smallest inside diameter portion of the connecting pipe in the vicinity of the connecting pipe and thermally expanding the smallest inside diameter portion of the connecting pipe. The outer diameter of the pipe to be connected is larger than that of the pipe to be connected. The inner diameter is set so as to be able to fit onto the connecting pipe. The length in the tube axis direction of the connecting pipe farthest from the water surface is the same as that of the connecting pipe closest to the water surface. It is short compared to the length of the direction.

[0010] The length of the connecting pipe in the axial direction is increased continuously or stepwise as it moves away from the water surface. It is preferable that the length of the slit is shortened substantially.

[0011] The outer surface of the pipe to be connected is in contact with the end of the pipe that is to be fitted into the connecting pipe. It is preferable that the outer diameter of the cylindrical member has a tapered surface in which the outer diameter of the cylindrical member is continuously reduced.

[0012] The inner surface of the connecting pipe is inclined from the minimum inner diameter portion toward the pipe to be connected. It is preferable that the connecting pipe has a tapered surface in which the inner diameter increases continuously.

[0013] The ratio of the length of the tapered surface along the axial direction of the connecting pipe to the thickness of the pipe is preferably 1 to 20.

[0014] The outer diameter of at least a part of the tapered surface is in the temperature range of -80°C to 50°C. , which is larger than the inner diameter of the connecting pipe at the opposing position, and the remaining part of the tapered surface The outer diameter is equal to or smaller than the inner diameter of the connecting pipe in a temperature range of -80°C to 50°C, and the connecting pipe By heating, the inner diameter of the connecting pipe at the opposing position becomes smaller than the inner diameter of the tapered surface. It is preferable that the outer diameter of the first portion is larger than the outer diameter of the second portion at least in part.

[0015] The inner diameter of at least a part of the tapered surface is in the temperature range of -80°C to 50°C. , the outer diameter of the pipe to be connected at the opposing position is smaller than the outer diameter of the pipe, and the tapered surface The inner diameter of the remaining portion is in the range of temperatures from -80°C to 50°C. The connecting pipe is heated to a temperature of at least one of the tapered surfaces. The inner diameter at the portion is larger than the outer diameter at the opposing position of the pipe to be connected. It is preferable that the

[0016] The carbon equivalent of the piping and the connecting pipe is preferably 0.43 mass % or more.

[0017] The tensile yield strength of the piping and the connecting pipe is 555 [N / mm] or more. preferable.

[0018] The long pipe is a pipe that is connected to at least 10 or more of the pipes by the connecting pipes and is vertically Extending in the direction The mass of each of the pipes is 100 kg to 10,000 kg, and each of the pipes The pipe thickness is preferably 5 mm to 100 mm.

[0019] The linear expansion coefficient of the connecting pipe between 50°C and 450°C is It is preferable that the elastic modulus is at least 20% larger than the elastic modulus.

[0020] In addition to heating the smallest inner diameter portion of the connecting pipe, the end of the pipe to be connected is heated. The inner diameter dimension is reduced by cooling the part to a temperature below 0° C. to shrink the outer diameter of the part. The outer diameter of the pipe to be connected becomes larger than the outer diameter of the pipe to be connected. The inner diameter is set so that the connecting pipe can be fitted thereto, and the heating temperature of the smallest inner diameter portion and the The temperature difference of the cooling temperature of the part including the end of the pipe to be connected is 50℃ to 400℃. It is preferable.

[0021] The cross-sectional shape of the inner surface of the connecting pipe is elliptical, and the cross-sectional shape of the outer surface of the pipe to be connected is elliptical. The cross section is also preferably elliptical.

[0022] It is preferable that the ratio of the minor axis to the major axis of the ellipse is 0.9 or more and less than 1.0. .

[0023] Another aspect of the present invention is to connect a plurality of pipes to the bottom of the water or to the underground below the bottom of the water. The present invention relates to a method for connecting a long pipe between a water surface and a water pipe. A pipe is provided that covers the outer surface of a portion including one end of the pipe and extends from at least one end of the pipe. a portion of the connecting pipe having a smallest inner diameter portion fixed to the outer surface of the piping is heated so as to The minimum inner diameter portion is connected at a temperature in the range of -80°C to 50°C. The inside diameter is smaller than the outside diameter of the pipe to be circulated, and the minimum inside diameter portion is kept at a temperature of 50° C. or less. By heating in a temperature range of up to 450°C and thermally expanding the front of the minimum inner diameter portion, making the inner diameter dimension larger than the outer diameter of the pipe to be connected; inserting the pipe to be connected into the thermally expanded connecting pipe; After inserting the pipe to be connected, the temperature of the connecting pipe is set to a temperature of -80℃ to 50℃. and returning the image to the optical axis range. The connecting pipe is made of tempered martensitic steel, austenitic stainless steel, or Austenitic and ferritic stainless steels are used.

[0024] The inner diameter of the minimum inner diameter portion is made larger than the outer diameter of the pipe to be connected. the step of heating the connecting pipe from an outer surface side, The step of returning the temperature of the connecting pipe to a temperature range of -80°C to 50°C includes removing the connecting pipe from the outside. It is preferable that the cooling method includes cooling from the face side.

[0025] Before inserting the pipe to be connected into the thermally expanded connecting pipe, A step of shrinking the outer diameter of the portion including the end of the pipe to be cut by cooling it to a temperature of less than -80°C. , preferably including.

[0026] In another embodiment of the present invention, a plurality of pipes are connected to each other to connect the water bottom or the underground below the water bottom. The present invention relates to a method for connecting a long pipe between a water surface and a water pipe. A pipe is provided that covers the outer surface of a portion including one end of the pipe and extends from at least one end of the pipe. The pipe is connected to the outside of the pipe via a connecting pipe having a minimum inner diameter portion fixed to the outside of the pipe. a step of cooling a portion including an end of a pipe to be connected to said smallest inner diameter portion is smaller than the outer diameter of the pipe to be connected in the temperature range of -80℃ to 50℃. The pipe has an inner diameter and is heated to a temperature of less than -80°C. By cooling and shrinking the pipe, the outer diameter of the pipe to be connected is reduced to the minimum inner diameter portion. making the inner diameter smaller than the inner diameter of the inserting the shrunk pipe to be connected into the connecting pipe; A portion including the end of the pipe to be connected after the pipe to be connected is inserted and returning the temperature to the temperature range of -80°C to 50°C. The connecting pipe is made of tempered martensitic steel, austenitic stainless steel, or Austenitic and ferritic stainless steels are used.

[0027] The outer diameter of the pipe to be connected is made smaller than the inner diameter dimension of the minimum inner diameter portion. The step of inserting the pipe to be connected into the pipe to be connected The cooling medium pipe is guided along the inner surface to the end of the pipe to be connected, and the cooling medium The end of the pipe to be connected is cooled by supplying a cooling medium from the pipe to the inner surface of the end. from the inner surface side of the pipe.

[0028] The outer diameter of the pipe to be connected is made smaller than the inner diameter dimension of the minimum inner diameter portion. The step of attaching a pipe to the end of the pipe to be connected includes attaching a pipe to the outer surface of the pipe to be connected. Preferably, the cooling medium is supplied from the side.

[0029] The part including the end of the pipe to be connected is brought to a temperature range of -80℃ to 50℃. The step is inserted into the inside of the pipe to be connected to The heating medium pipe is guided along the pipe to the end of the pipe to be connected, and the heating medium pipe is The end of the pipe to be connected is heated by supplying a heating medium to the inner surface of the end. It is preferable that the heating method includes heating the pipe from its inner surface side.

[0030] In another embodiment of the present invention, a plurality of pipes are connected to each other to connect the water bottom or the underground below the water bottom. The present invention relates to a method for connecting a long pipe between a water surface and a water pipe. A pipe is provided that covers the outer surface of a portion including one end of the pipe and extends from at least one end of the pipe. a portion of the connecting pipe having a smallest inner diameter portion fixed to the outer surface of the piping is heated so as to The minimum inner diameter portion is connected at a temperature in the range of -80°C to 50°C. The inside diameter is smaller than the outside diameter of the pipe to be circulated, and the minimum inside diameter portion is kept at a temperature of 50° C. or less. By heating in a temperature range of up to 450°C and thermally expanding the front of the minimum inner diameter portion, making the inner diameter dimension larger than the outer diameter of the pipe to be connected; inserting the pipe to be connected into the thermally expanded connecting pipe; After inserting the pipe to be connected, the temperature of the connecting pipe is set to -80℃~50℃. and c) returning the range. The step of inserting into the connecting pipe is repeated; The length of the connecting pipe in the tube axial direction used in the step of inserting the connecting pipe is As the number of repetitions of the insertion step increases, the length increases continuously or in stages. do.

[0031] When the pipe to be connected is inserted into the thermally expanded connecting pipe, The outer surface of the pipe has a tapered surface in which the outer diameter continuously decreases to the end of the pipe. It is preferable to insert the connecting pipe.

[0032] The inner surface of the connecting pipe is inclined from the minimum inner diameter portion toward the pipe to be connected. It is preferable that the connecting pipe has a tapered surface in which the inner diameter increases continuously.

[0033] The heating temperature of the connecting pipe and the temperature after cooling of the part including the end of the pipe to be connected It is preferable that the temperature difference is set to 50°C to 400°C.

[0034] The cross-sectional shape of the inner surface of the connecting pipe is elliptical, and the cross-sectional shape of the outer surface of the pipe to be connected is elliptical. The cross-sectional shape is also elliptical. When the pipe to be connected is inserted into the thermally expanded connecting pipe, The direction of the minor axis of the ellipse of the pipe to be inserted is aligned with the direction of the minor axis of the ellipse of the connecting pipe. It is preferable to include

[0035] A cross-sectional shape of the inner surface of the connecting pipe before the pipe to be connected is inserted into the connecting pipe. is a perfect circle, and the cross section of the outer surface of the pipe to be connected is also a perfect circle, After the pipe to be connected is inserted into the connecting pipe, the connecting pipe and the connected pipe are A step of applying compressive stress from the outside of the tube in a direction perpendicular to the tube axial direction to make the tube elliptical. Yes, it is preferable.

[0036] Another aspect of the present invention is to connect a plurality of pipes to the bottom of the water or to the underground below the bottom of the water. The pipe connection device connects a long pipe that extends between the water surface and the pipe. The device is A pipe that receives a connecting pipe, and covers the outer surface of a portion including the end of the connected pipe. A connecting pipe is fixed to the outer surface of the connecting pipe so as to extend from the end of the connecting pipe. a connected pipe gripping portion that grips the pipe in an upright position; The connecting pipe is held in an upright position by a connecting pipe gripping portion. A connection pipe gripping portion; In order to bring the end of the connecting pipe closer to the connecting pipe, the connecting pipe gripping portion is A moving mechanism for moving the tube gripping portion relative to the tube gripping portion; In order to connect the connecting pipe and the connected pipe, the smallest inner diameter portion of the connecting pipe is heated. A process of thermally expanding the end of the connecting pipe and cooling the end of the connecting pipe to reduce the outer diameter of the end of the connecting pipe. and a heat treatment apparatus for performing at least one of the processes of:

[0037] The gripping contact area of ​​the connection pipe gripping portion that contacts and grips the connection pipe is It is preferable that the pipe gripping portion has a gripping contact area larger than the gripping contact area of ​​the pipe to be connected. It is.

[0038] The connecting pipe gripping portion is provided on the opposing surfaces of the connecting gripping portion and the connected gripped portion. A measurement unit that measures the presence or absence of a misalignment in the direction or position between the connecting pipe gripping portion and the connecting pipe gripping portion. It is preferred that a slot is provided.

[0039] A pipe that is arranged to cover the outer periphery of the connection pipe and has a diameter that expands toward the connection pipe gripping portion. It is preferable that the nozzle further comprises a tubular expanding member.

[0040] In order to connect and fix the connecting pipe to the connected pipe, a cover is provided to cover the outer periphery of the connecting pipe. a connecting pipe gripping portion for gripping the connecting pipe and connecting the connecting pipe to the connecting pipe; The connecting pipe gripping portion is moved to the uppermost end of the connected pipe to hold the connecting pipe in the connected pipe. When connecting to a pipe, the outer circumference of the connecting pipe rotates in the circumferential direction at a speed of 0 to 1 revolution per second. It is preferable to provide a rotation mechanism for imparting the following rotation speed to the connecting pipe.

[0041] The connection pipe gripping portion grips the outer periphery of the connection pipe before connection so as to cover the outer periphery of the connection pipe. The connecting pipe gripping portion is configured such that the moving mechanism moves the connecting pipe gripping portion closer to the connected pipe gripping portion. When the connecting pipe is connected to the connecting tube, the outer periphery of the connecting pipe rotates in the circumferential direction. A rotation mechanism is provided to impart a rotation speed of more than 0 and not more than 1 rotation / second to the connecting pipe so as to rotate the connecting pipe. , is preferred. Effect of the Invention

[0042] According to the above-mentioned pipe connection mechanism, pipe connection method, and pipe connection device, the tensile load of the long pipe can be reduced. On the other hand, the mechanical strength of the piping can be ensured. [Brief description of the drawings]

[0043] [Figure 1] 1 is a schematic diagram of a resource recovery system to which a piping connection mechanism and a piping connection method for a riser pipe according to an embodiment are applied. [Diagram 2] 1 is a diagram for explaining an example of a connection form of a pipe connection mechanism according to an embodiment; [Diagram 3] 4A and 4B are diagrams illustrating in detail an example of a connecting pipe and an end of a pipe used in the pipe connection mechanism of the embodiment. [Figure 4] 13 is a detailed diagram illustrating another example of a connecting pipe and an end of a pipe used in the pipe connection mechanism of the embodiment. FIG. [Diagram 5] FIG. 5 is a detailed view of a modification of the example of the connecting pipe and the end of the pipe shown in FIGS. 3 and 4. [Figure 6] 4A to 4C are diagrams illustrating an example of a cross-sectional shape of a pipe and a connecting pipe used in the pipe connection mechanism of the embodiment. [Figure 7] 1A and 1B are diagrams illustrating an example of a pipe connecting method according to an embodiment. [Figure 8] 13(a) and 13(b) are diagrams illustrating an example of a pipe connecting method according to another embodiment. [Figure 9] 1A and 1B are diagrams illustrating an overview of a pipe connecting device that performs a pipe connecting method according to one embodiment. [Figure 10] 1 is a diagram showing an example of a pipe connection device according to an embodiment; [Figure 11] 1 is a diagram showing an example of a pipe connection device according to an embodiment; [Figure 12] 1 is a diagram showing an example of a pipe connection device according to an embodiment; [Figure 13] 1 is a diagram showing an example of a pipe connection device according to an embodiment; [Figure 14] 1 is a diagram showing an example of a pipe connection device according to an embodiment; [Figure 15] 1 is a diagram showing an example of a pipe connection device according to an embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] The following describes in detail the piping connection mechanism and the piping connection method for the long pipe of this embodiment. A long pipe is a pipe that is at least 400m long and is made up of multiple connected pipes. The long pipe is used, for example, with the pipe extending in a substantially vertical direction. As a means of lifting solid or liquid substances that are on or below the bottom of the water to the surface In addition to the riser pipe, liquid or solid materials on the water surface are transported to or near the bottom of the water. This can also be applied to the supply pipe. FIG. 1 shows a riser pipe connection mechanism and a riser pipe connection method according to an embodiment of the present invention. FIG. 1 is a schematic diagram of a resource recovery system. In the embodiment described below, an example is taken in which resources on the ocean floor are pulled up using a drilling ship. However, the applicable locations are not limited to oceans, but can also be applied to lakes and rivers. do.

[0045] The lift system 10 shown in FIG. 1 is a drilling vessel 12 that floats on the water surface (ocean surface) and is used to drill the ocean floor or the ocean floor. The lift system 10 is used to raise resources below the bottom. The system mainly comprises a lift device 22, a collection device 26, and a processing device 28.

[0046] The lift system 10 is adapted to lift the bottom of a body of water, such as a seabed, lake bed, or river bed, or the sand or sediment below the bottom of the body of water. A slurry containing solid substances such as minerals or liquid substances is passed through a riser pipe 20 and fed to the water. A lifting device 22 is provided on the riser pipe 20 to lift it to the surface. 0 is a pressure reduction effect in the riser pipe 20 due to the function of the lift device 22. The sediments collected by the collector 26 are collected from the lower end of the riser pipe 20 together with the surrounding water. The lift device 2 can be used to suck the water into the water and pull it up to the water surface together with water or gas. 2 may be a jet pump that discharges high-pressure jet water toward the sea surface, Gas is supplied to the inside of the pumping pipe 20 to form bubbles, and the slurry is then pulled into the sea by utilizing the rising force of the bubbles. The bubble lift device may be a bubble lift device that lifts the liquid to the surface, and may also be a jet pump and a bubble lift device. A combination of a jet pump and a bubble lift device may also be used. In this case, the bubble lift device is provided in the middle of the riser pipe 20 and is extended from the lower end of the riser pipe 20. The lift force of a jet pump provided near the lower end of the riser pipe 20 is applied from the riser pipe 20 to the bubble lift device. It is preferable that the slurry is fried by means of a stirrer.

[0047] The drillship 12 is a vessel equipped with a drilling mechanism equipped with a dynamic positioning system. The riser pipe 20 of the system 10 is the riser pipe used by the drilling ship 12. The riser pipe of the drillship 12 is used to collect drilling mud during drilling. The riser pipe 20 is used to collect slurry containing solid or liquid materials from the bottom of the water. A pipe for raising the vessel above the water surface. A riser pipe, for example, has an inner diameter of 50 cm and a length of 27 m. The riser pipe 20 is made up of a number of pipes connected together in a manner described below. A collector 26 is connected to the side.

[0048] The collector 26 is a device that collects material on or below the ocean floor. The configuration of 26 is not particularly limited, but for example, a caisson having suction capacity is placed in contact with the seabed. The device pushes the magnet into the seabed or inside the seabed, sucking up the sediments on the seabed or inside the seabed. The inner space of the caisson has nozzles that spray high-pressure water, and the water that is drawn into this inner space The collected sediment is converted into fine particles or liquid (fluidized) by high-pressure water, and the solid or liquid material is The sucked solid or liquid material is collected and collected as a slurry. The riser pipe 20 is connected to the lower end of the device 26. A conventional suction head can also be used. An example of such a caisson or suction head is disclosed in Japanese Patent Application Laid-Open No. 2018-532918. Examples of such caissons include those described in the report.

[0049] The riser pipe 20 includes a plurality of pipes and a connecting pipe. It is composed of the following: FIG. 2 shows a connection form of the multiple pipes constituting the riser pipe 20, in which the pipes 30 and 34 are connected to each other. FIG. 13 is a diagram for explaining an example of a continuation mode. The pipe 30 is provided with a portion including one end 30a of the pipe 30, which covers the outer surface of this portion and has a A connecting pipe having a minimum inner diameter portion is fixed to the outer surface of the pipe 30 so as to extend from the connecting pipe 30a. 32 will be provided. A pipe 34 to be connected to this pipe 30 is inserted into the connecting pipe 32 and connected. Here, the length of the connecting pipe 32 is more than 0% and not more than 50% of the length of the pipe 30 in the axial direction, for example. The length of the connecting pipe 32 is 1% or more and 20% or less, and the portion in the range of more than 1% and 80% or less of the length of the connecting pipe 32 is The connecting pipe 32 is fixed to the pipe 30 by welding. Alternatively, they may be joined by fitting.

[0050] In this manner, the pipe 30 and the pipe 34 to be connected are connected via the connecting pipe 32. Therefore, although not shown, the end of the pipe 34 opposite to the end connected to the pipe 30 is also included. A connecting pipe similar to the connecting pipe 32 is provided at the portion where the pipe is to be connected to other pipes. The pipes 30, 34 and the connecting pipe 32 are made of a metal material.

[0051] The pipe 34 is configured to be connected to the pipe 30 via the connecting pipe 32. Specifically, The smallest inner diameter portion of the connecting pipe 32 is designed to be connected in a temperature range of -80°C to 50°C. The inner diameter is smaller than the outer diameter of the pipe 34. The inner diameter is at least 50° C. The smallest inner diameter portion of the connecting pipe 32 is heated to a temperature range of 450° C. or higher to cause thermal expansion. As a result, the outer diameter of the connecting pipe 30 becomes larger than the outer diameter of the pipe 34 to be connected, and the connecting pipe 30 can be fitted thereto. In other words, the shrink fitting technique is used. The minimum inner diameter portion of the connecting pipe 32 has an inner diameter smaller than the inner diameter of any other portion of the inner surface of the connecting pipe 32. In addition to the smaller part, the entire inner surface of the connecting pipe 32 when the inner diameter of the inner surface is constant is also included. The upper limit of the heating temperature of the smallest inner diameter portion of the connecting pipe 32 is set to 450° C. The upper limit of the temperature difference between the heat temperature and the temperature of the pipe 34 to be connected is set to 400°C. If the heating temperature exceeds 450° C., the strength of the connecting pipe 32 is reduced. arises.

[0052] The heating of the smallest inner diameter portion of the connecting pipe 32 is performed by passing electricity through the connecting pipe 32 itself. Heating may be performed by electrical heating, high-frequency induction heating, or infrared heating. Heating may be performed using an apparatus.

[0053] The metal material of the connecting pipe 32 is austenitic stainless steel (e.g., S US304) or austenitic-ferritic stainless steel is used. Tennitic-ferritic stainless steels are duplex stainless steels (e.g., SUS329J 4L), a stainless steel consisting of austenite and ferrite phases. Ferritic stainless steels are austenitic stainless steels such as SUS304. It has a lower Ni content than stainless steel. These metal materials are high-strength steels with high tensile yield strength, and are used to connect multiple pipes. It extends between the bottom of the water or the ground below the bottom of the water and the water surface, and the part closer to the water surface is This is suitable for long pipes that are greatly affected by tensile loads due to their own weight. The closer to the surface, the greater the downward tensile load, so the connecting pipe will not plastically deform or break. A high tensile yield strength is required to prevent cracks.

[0054] In this manner, the connecting pipe 32 is used to connect the pipe 30 and the pipe 34, and the connecting pipe 32 By connecting the two parts using shrink fitting technology, the weight is reduced compared to conventional flange joints. Furthermore, since the riser pipe 20 itself is joined using a welded joint, the conventional It is possible to use materials with higher strength than the riser pipe material, and the pipe thickness can be made thinner. Therefore, the total weight of the riser pipe 20 can be reduced, and further, the occurrence of fatigue cracks can be reduced. Since there are no easily welded parts, the mechanical properties of the connection part of the pipe 34 against the tensile load of the riser pipe 20 are The required strength can be ensured.

[0055] According to one embodiment, the connecting pipe 32 that is the furthest from the water surface in the pipe axial direction is The length is preferably shorter than the length in the tube axis direction of the connecting tube closest to the water surface. The direction refers to the longitudinal direction of the connecting pipe. Therefore, in the case of the configuration shown in Figures 3 and 4, , the pipe longitudinal direction of the pipes 30 and 34. In particular, the length of the connecting pipe 32 in the pipe axial direction is It is preferable that the length of the line be shortened continuously or stepwise as the line moves away from the target. The tensile load applied to the connecting pipe 32 is smaller for each connecting pipe 32. The length of the riser can be shortened to weaken the strength of the piping connection. The total weight of the pipe 20 can be reduced, so that the load on the connecting pipe 32 located at a shallow depth can be reduced. The tension load can be reduced, and the increase in the axial length of the connecting pipe 32 located at a shallow water depth is suppressed. It can be controlled.

[0056] FIG. 3 is a detailed view of an example of the ends of the connecting pipe 32 and the pipes 30 and 34. As shown, the inner diameter of the connecting pipe 32 is constant, whereas the inner diameter of the pipe 34 to be connected is constant. The outer surface of the pipe 34 is such that the outer diameter of the pipe 34 is increased toward the end 34a on the side where the pipe 34 is fitted into the connecting pipe 32. The outer diameter of the pipe 34 is tapered continuously. The inner diameter of the pipe 34 at the part surface 34b does not change. When the tapered surface 34b is not present, the heated and expanded connecting pipe 32 is inserted into the connecting pipe 32. The inner diameter of the pipe 32 is only slightly larger than the outer diameter of the pipe 34. It is difficult to smoothly and quickly insert the area including the end 34a of the tape into the connecting tube 32. When the piping surface 34b is not provided, the outer diameter of the piping to be connected and the connecting pipe 32 are The ratio of the difference from the maximum inner diameter to the maximum inner diameter of the connecting pipe 32 is preferably more than 0% and less than 10%. In most cases, the difference is very small, between 0.001% and 8%, making smooth and quick insertion difficult. In particular, since the connection work is carried out on the ocean, for example on a ship, where there is a lot of rocking, the connection between the pipes 34 must be 3 2. By providing the pierced surface 34b, the insertion of the piping 34 into the connecting pipe 32 can be performed smoothly and quickly. Moreover, the tapered surface 34b allows the connection pipe 32 to be inserted into the depth of the connection pipe 32. The pipes 34 can be accurately positioned in a direction perpendicular to the row direction.

[0057] FIG. 4 is a detailed view of another example of the ends of the connecting pipe 32 and the pipes 30 and 34. As shown in FIG. 1, the outer diameter of the pipe 34 is constant, while the inner surface of the connecting pipe 32 is The inner diameter of the connecting pipe 32 is extended from the connecting pipe 32 toward the side of the pipe 34 to be connected to the connecting pipe 32 until the opening end of the connecting pipe 32 It has a tapered surface 32a that expands continuously. When the pipe 34 is inserted into the connecting pipe 32 using a shrink fitting technique, the tapered surface 32a If there is no heat, the inner diameter of the connecting pipe 32 that is heated and expanded will be much larger than the outer diameter of the pipe 34. Since the area including the end 34a of the pipe 34 is only slightly larger than the connecting pipe 32, the area including the end 34a of the pipe 34 can be smoothly and quickly connected to the connecting pipe 32. It is difficult to insert the wires quickly. Especially when joining is done on the ocean, for example on a ship, where there is a lot of rocking. It becomes even more difficult to insert the piping 34 smoothly and quickly. By providing a tapered surface 32a on the inner surface from the region including the pipe 34, it is possible to insert the pipe 34 into the connecting pipe 32. Moreover, the taper surface 32a of the connecting pipe 3 Since the inner diameter becomes smaller as it advances in the depth direction of 2, The pipe 34 can be accurately positioned in the direction.

[0058] In the example shown in FIG. 4, the inner surface of the connecting pipe 32 on the side of the piping 30 also has a tapered surface 32a. However, the connecting pipe 32 is fixed to the piping 30 in advance by welding or shrink fitting on land. Therefore, the tapered surface 32a does not necessarily have to be provided on the pipe 30 side.

[0059] FIG. 5 shows in detail a modification of the example of the connecting pipe 32 and the ends of the pipes 30, 34 shown in FIGS. This is a diagram. As shown in FIG. 5, the pipe 34 is provided with a tapered surface 34b, similar to the example shown in FIG. Furthermore, the inner surface of the connecting pipe 32 is provided with a smallest inner diameter portion of the connecting pipe 32 and a smallest inner diameter portion of the piping 34. A tapered surface 32a is provided so that the inner diameter of the connecting pipe 32 increases continuously toward the side. This allows the region including the end 34a of the pipe 34 to be inserted smoothly and quickly into the connecting pipe 32. It is possible. The tapered surface 32a and the tapered surface 34b are mutually insulated in a temperature range of -80°C to 50°C. The inclination of the tapered surface 32a and the tapered surface 34b with respect to the tube axis direction X is set so that the tapered surface 32a and the tapered surface 34b come into contact with each other. Preferably, the angle is set. Furthermore, the tapered surface 32a and the tapered surface 34b cause the suction pipe 32 to advance in the depth direction of the connecting pipe 32. Since the inner diameter of the connecting pipe 34 is smaller, the inner diameter of the pipe 3 is smaller in the direction perpendicular to the depth direction. 4 can be accurately positioned, and the pipe 34 can also be accurately positioned in the depth direction. It can be positioned.

[0060] At this time, the tapered surface 32a and the tapered surface 34b are joined to each other. The inclination angles of the tapered surface 32a and the tapered surface 34b with respect to the tube axis direction X are the same, It is also preferable that the lengths of 2a and tapered surface 34b in the tube axial direction are the same. The inner diameter of the tapered surface 32a is set to a value in the range of temperatures from -80°C to 50°C. The inner diameter is smaller than the outer diameter of the corresponding portion of the tapered surface 34b of the tube 34, This inner diameter dimension must be at least 3 mm thick at a temperature range of 50°C to 450°C. By heating and thermally expanding 2a, the outer diameter becomes larger than the above-mentioned dimension, and the temperature of the connecting pipe 32 The tapered surface 34b of the pipe 34 is designed so that it can fit into the tapered surface 34b of the pipe 34. It is preferable that the above-mentioned range is set. As a result, the tapered surfaces 32a and 34b are fitted together by shrink fitting, so that the connecting pipe 3 The connection between the pipe 30 and the pipe 34 via 2 can be made stronger.

[0061] In the example shown in FIG. 5, a tapered surface 32a is also provided on the inner surface of the connecting pipe 32 on the side of the pipe 30. However, the inner surface of the connecting pipe 32 on the pipe 30 side is not necessarily provided with a tapered surface 32a. It's not necessary.

[0062] According to one embodiment, the junction of the tapered surface 34b shown in FIG. 3 and the tapered surface 32a shown in FIG. The ratio of the length l [mm] of the connecting pipe 32 along the pipe axis to the pipe thickness t [mm] of the pipe 34 The fact that the number of the pipes 34 is 1 to 20 enables the pipe 34 to be inserted into the connecting pipe 32 smoothly and in a short time. The thickness t [mm] of the pipe 34 is preferably set to a value that is smaller than the taper surface 34 of the pipe 34. b is the thickness of the portion where no material is provided.

[0063] According to one embodiment, the linear expansion coefficient (linear expansion coefficient between 50° C. and 450° C.) of the material of the connection pipe 32 is The linear expansion coefficient (linear expansion coefficient between -80℃ and 50℃) of the material of the pipe 34 to be connected is The above shrink fitting technique is used appropriately to ensure that the riser The resultant vertical force acting on the pipe 20 is the tensile load (total weight of the riser pipe 20 - the total weight of the riser pipe The material of the connecting pipe 32 is preferable for realizing a connection between the pipes that can withstand the buoyancy of the connecting pipe 32. The linear expansion coefficient (linear expansion coefficient between 50°C and 450°C) is determined by the material of the pipe 34 to be connected. It is more preferable that the linear expansion coefficient is 20% or more higher than that of the It is preferable that the riser pipe 20 is welded to the conventional joint. When connecting, if the carbon equivalent is high, it is likely to cause a decrease in the toughness of the base material and the circumferential weld. Therefore, it is necessary to suppress the carbon equivalent in order to improve the strength. Since no welded joints are used for the pipes 30 and 34, the carbon equivalent of the pipes 30 and 34 can be reduced. It is possible to make the amount of Cr content at 0.43 mass % or more without increasing the amount of Cr, and it is possible to easily achieve high strength. In order to increase the strength of the connecting pipe 32, the carbon equivalent is preferably 0.43 mass % or more. It is. The carbon equivalent Ceq (mass%) is Ceq = C + Mn / 6 + Si / 24 + Ni / 40 +Cr / 5+Mo / 4+V / 14 (C, Mn, Si, Ni, Cr, Mo, V are respectively , the mass percent of carbon, manganese, nickel, chromium, molybdenum, and vanadium contained ) can be expressed as The pipes 30, 34 of the riser pipe 20 and the connecting pipe 32 are each provided with a brazing material to ensure mechanical strength. Tensile yield strength is 555 [N / mm 2 At this time, it is preferable that the pipe 30 ,34, for example, the linear expansion coefficient is 12×10 -6 [ / ℃] For example, when using SCM440H QT material, the connecting pipe 32 has a linear expansion coefficient of, for example, 16×10 -6[ / ℃] Austenitic stainless steel (e.g. SUS304) It is recommended to use:

[0064] The riser pipe 20 (long pipe) is connected to at least 10 pipes 30, 34, for example. The pipes 30 and 34 are connected by a pipe 32 and extend vertically. The mass of each of the pipes 30 and 34 is 10 The load is 0kg to 10,000kg, and the thickness of each pipe is 5mm to 100mm. In this case, more than 10 large mass pipes are connected, and the pipes located near the water surface are relatively thin. Even if the piping is subjected to a large tensile load caused by the mass of the piping, the material has a high tensile yield strength. Since the pipes 30 and 34 are made of a material that is not easily deformed plastically, the connecting pipe 32 does not have a flange portion as in the conventional art. Since the mass of the connecting mechanism is smaller than that of the connecting mechanism having a tensile load, the tensile load can be suppressed. The length of each of the pipes 30 and 34 is, for example, 3000 mm to 30,000 mm. .

[0065] According to one embodiment, in addition to heating the smallest inner diameter portion of the connecting tube 32, the pipe to be connected is heated. The portion including the end 34a of the tube 34 is cooled to a temperature of less than -80°C to shrink the outer diameter of the portion. By this, the inner diameter dimension of the smallest inner diameter portion is made larger than the outer diameter dimension of the pipe 34. The inside diameter of the smallest inside diameter portion of the connecting pipe 32 is set so that the connecting pipe 32 can be fitted with the The heating temperature of the smallest inner diameter part of the connecting pipe 32 and the cooling temperature of the part including the end of the pipe 34 are set. It is preferable that the temperature difference is set to 50° C. to 400° C. A relatively large gap can be provided between the inner surface of the portion and the outer surface of the portion including the end of the pipe 34. Therefore, the pipe 34 can be smoothly and quickly inserted into the connecting pipe 32.

[0066] The portion of the pipe 34 including the end 34a can be cooled by immersing it in liquid nitrogen or by A cooling medium such as liquid nitrogen is sprayed onto the end 34a of the pipe 34 to cool it. Alternatively, cooling may be performed using a Peltier element, or by magnetic cooling (magnetic refrigeration). Cooling may be performed.

[0067] In addition, the surface of the joint portion of the outer surface including the end of the pipe 34 that is joined to the inner surface of the connecting pipe 32 and the pipe 34 are The surface of the inner surface of the connecting pipe 32 that joins with the joint of the pipe 34 improves friction. For this reason, the surface is preferably roughened.

[0068] According to one embodiment, the outer diameter of at least a portion of the tapered surface 34b shown in FIG. In the temperature range of -80°C to 50°C, the inner diameter is larger than the inner diameter of the connecting pipe 32 at the opposing position, and the temperature The outer diameter of the remaining part of the surface is 32 mm. The inner diameter of the connecting pipe 32 is equal to or smaller than the opposing inner diameter of the connecting pipe 32, and when the connecting pipe 32 is heated, The inner diameter at this point is larger than the outer diameter at least at the portion of the tapered surface 34b. is preferred. According to one embodiment, the inner surface of at least a part of the tapered surface 32a shown in FIG. The diameter is determined by the temperature range of -80°C to 50°C. The inner diameter of the remaining portion of the tapered surface 32a is smaller than the outer diameter. ℃ range, the outer diameter of the pipe 34 to be connected is larger than that, and by heating the connecting pipe 32 The inner diameter of at least the part of the tapered surface 32a is It is preferable that the outer diameter of at least one of the tapered surfaces 34b and 32a is larger than the outer diameter of the tapered surface 34b. By applying shrink fitting technology to the fitting area, the fitting area can be expanded, reducing friction. As a result, the piping connections can be sufficiently maintained even with respect to the total weight of the riser pipe 20.

[0069] FIG. 6 is a diagram illustrating an example of a cross-sectional shape of a pipe and a connecting pipe according to an embodiment. As shown in FIG. 1, according to one embodiment, the cross-sectional shape of the inner surface of the connecting pipe 32 is an ellipse. The outer pipe cross section of the pipe 34 to be connected is also elliptical. This is preferable because it can suppress the occurrence of rotational deviation caused by the rotation of the pipe 34 around the central axis of the pipe 34. Similarly, the cross section of the outer surface of the piping 30 is preferably elliptical. In addition, if the cross-sectional shape of the outer surface of the pipe 34 is a perfect circle, when the pipe 34 rotates, Rotational misalignment occurs between the pipe 34 and the connecting pipe 32, and the frictional force in the pipe axis direction X decreases, causing the riser pipe The resultant vertical force of the riser pipe 20 is the tensile load (total weight of the riser pipe 20 - buoyancy of the riser pipe 20) ) may make it difficult for the connecting pipe 32 to be removed from the piping 34. The ratio of the minor axis of the ellipse to the major axis is 0.9 or more and less than 1.0 to suppress rotational deviation. When the ratio of the minor axis to the major axis is less than 0.9, the distribution The radius of curvature of the outer surface of the pipe 34 varies greatly, so that the high pressure The compressive pressure that the pipes are subjected to in the environment also varies from place to place, which results in the maximum compressive stress and In some cases, the compressive stress exceeds the mechanical strength of the pipe 34, causing damage to the pipe 34. It becomes easier. The elliptical cross section is obtained by, for example, replacing the pipe 34 having a circular cross section with a pipe having a circular cross section. In a state where the pipe 34 is fitted into the connecting pipe 32, the pipe 34 and the connecting pipe 32 are in a direction perpendicular to the pipe axis direction. It may be obtained by applying compressive stress from the side to cause plastic deformation, or by applying compressive stress to the pipe 34 before fitting. And the cross section of the connecting pipe 32 may already be elliptical.

[0070] The connection mechanism for such a long pipe such as the riser pipe 20 is based on the following long pipe connection method. It can be obtained. (1) Covering the outer surface of the portion including one end 30a of the pipe 30 and at least one A joint having a minimum inner diameter portion is fixed to the outer surface of the pipe 30 so as to extend from the end 30a of the pipe 30. A part of the connecting tube 32 is heated. The part with the smallest inner diameter to be heated is heated at a temperature of -80°C to 50°C. Within the range of the minimum inner diameter, the inner diameter is smaller than the outer diameter of the pipe 34 to be connected. The diameter part is heated to a temperature range of 50°C to 450°C to cause thermal expansion. Therefore, the inside diameter of the smallest inside diameter portion is made larger than the outside diameter of the pipe 34 to be connected. (2) Next, the pipe 34 to be connected is inserted into the thermally expanded connecting pipe 32. (3) The temperature of the connecting pipe 32 into which the piping 34 is inserted is returned to the temperature range of -80°C to 50°C. The method of returning the temperature of the connecting pipe 30 to the temperature range of -80°C to 50°C is air cooling, water cooling, air cooling and water cooling. In the case of water cooling, for example, the pipes 30 and 34 are connected to each other. The connection portion of the pipe 32 is restrained using a fixing jig, and in this restrained state, it is immersed in seawater or in seawater. After cooling by spraying water or a cooling medium, the fixture is removed. The connecting pipe 32 is made of tempered martensitic steel, austenitic stainless steel, or Austenitic and ferritic stainless steels are used.

[0071] In the above (1), the inner diameter is made larger than the outer diameter of the pipe 34 to be connected. At this time, the connecting pipe 32 is heated from the outer surface side, and the temperature of the connecting pipe 32 is reduced to -8 When returning the temperature to the range of 0° C. to 50° C., it is preferable to cool the connecting pipe 32 from the outer surface side.

[0072] In addition, the connection mechanism for long pipes such as the riser pipe 20 is different from the above-mentioned piping connection method in the following length: This can be achieved by using a long pipe piping connection method. (4) Covering the outer surface of the portion including one end 30a of the pipe 30 and at least one A joint having a minimum inner diameter portion is fixed to the outer surface of the pipe 30 so as to extend from the end 30a of the pipe 30. The portion including the end of the pipe 34 to be connected to the pipe 30 through the connecting pipe 32 is cooled. The minimum inner diameter of the pipe 34 to be connected is in the temperature range of -80°C to 50°C. The inside diameter of the pipe 34 is smaller than the diameter of the pipe 34. The pipe 34 is heated to a temperature of -8 By cooling the pipe 34 to a temperature below 0° C., the outer diameter of the pipe 34 to be connected is reduced to the minimum inner diameter of Make it smaller than the inside diameter. (5) Next, the contracted pipe 34 to be connected is inserted into the connecting pipe 32. (6) A part including the end of the pipe 34 to be connected after the pipe 34 to be connected is inserted Return the temperature to the -80℃ to 50℃ range. The connecting pipe 32 is made of tempered martensitic steel, austenitic stainless steel, or Austenitic and ferritic stainless steels are used.

[0073] 7(a) and (b) are diagrams showing an example of a pipe connecting method according to an embodiment. 3 is a cross-section of the pipe 34 and the cooling medium pipe 35 taken along a plane perpendicular to the longitudinal direction of the pipe 34. 7(b) shows a cross section of the pipe 34 along a plane including the center of the pipe 34 and parallel to the longitudinal direction of the pipe 34. 4 shows cross sections of the connected pipe 34 and the cooling medium pipe 35. The outer diameter of the pipe 34 to be connected is made smaller than the inner diameter of the smallest inner diameter portion of the connecting pipe 32. When connecting the pipe 34, as shown in Figs. 7(a) and (b), the pipe 34 is inserted into the pipe 34 to be connected. The pipe 34 is inserted along the inner surface of the pipe 34 to be connected, and the pipe 35 is connected to the pipe 34. The cooling medium C is supplied to the inner surface of the end of the pipe 34 from the cooling medium pipe 35. It is preferable to cool the end of the pipe 34 to be connected from the inner surface side of the pipe 34. The cooling medium pipe 35 is provided with a diameter of 1.0 mm on the outside of the pipe 34 so that the cooling medium pipe 35 is positioned at the center of the pipe 34. A plurality of arms 35a extending in the direction of the arrow and a plurality of rotors 35 provided at the tip of each of the arms 35a. The arms 35a and the rotors 35b are arranged at a plurality of positions in the longitudinal direction of the cooling medium pipe 35. The rotors 35b are provided at three locations in the example shown in FIG. 7(b). The cooling medium pipe 35 has a length long enough to contact the inner surface of the pipe 34. The cooling medium C is guided to the end of the pipe 34 while passing through the approximate center. The cooling medium C is cooled to a temperature of less than -80°C. Therefore, for example, liquid nitrogen is preferably used.

[0074] In the example shown in FIGS. 7(a) and 7(b), the outer diameter of the pipe 34 to be connected is set to the When the inner diameter of the pipe 34 is smaller than the minimum inner diameter of the pipe 32, the cooling medium is applied to the inner surface of the end of the pipe 34. The cooling medium is supplied to the end of the pipe 34 from the outer surface side of the pipe 34 to cool it from the inner surface side. It is also preferable to cool the material from the outside by supplying the material with water.

[0075] 8(a) and (b) are diagrams showing an example of a pipe connecting method according to another embodiment. 3A) is a diagram of the pipe 34 and the heating medium pipe 36 cut along a plane perpendicular to the longitudinal direction of the pipe 34. FIG. 8(b) shows a cross section of the pipe 34, taken along a plane including the center of the pipe 34 and parallel to the longitudinal direction of the pipe 34. A cross section of the cut pipe 34 and the heating medium pipe 36 is shown. When the part including the end of the cooled pipe 34 is returned to the temperature range of -80°C to 50°C, the pipe 34 The heating medium pipe 36 is inserted into the inside of the pipe 34 along the inner surface of the pipe 34 and guided to the end of the pipe 34. By supplying the heating medium H from the heat medium pipe 36 to the inner surface of the end, the end of the pipe 34 is heated to the temperature of 1000° C. It is preferable to heat the inside surface of the container. The heating medium pipe 36 is provided with a diameter 20 mm around the outside of the heating medium pipe 36 so that the heating medium pipe 36 is positioned at the center of the pipe 34. A plurality of arms 36a extending in the direction of the arrow and a plurality of rotors 36 provided at the tip of each of the arms 36a. The arms 36a and the rotors 36b are arranged at a plurality of positions in the longitudinal direction of the heating medium pipe 36. The rotors 36b are provided at three locations in the example shown in FIG. The heating medium pipe 36 has a length long enough to contact the inner surface of the pipe 34. The heating medium H is guided to the end of the pipe 34 while passing through the center. Since heating is required, for example, water or seawater is preferably used.

[0076] The above method is a method for connecting pipes. However, the separation and recovery of pipes is done when connecting pipes. The areas that are heated for expansion may be cooled, and the areas that are cooled for contraction may be heated.

[0077] According to one embodiment, the piping 34 is repeatedly inserted into the connecting pipe 32 to create a long pipe. When manufacturing the pipe 34, the length of the pipe 34 inserted into the connecting pipe 32 in the pipe axial direction is As the number of repetitions increases, the length is increased continuously or in stages. When preparing a long pipe (e.g., riser pipe 20) to extend between The connecting pipe 32 is inserted and connected while being submerged under the water surface. On the other hand, the last connected connecting pipe 32 is located near the water surface. The connecting pipe 32 located near the water surface is subject to a large tension caused by the total weight of the long pipe. Since the connecting pipe 32 is subjected to a load, in order to increase the strength of the connection of the connecting pipe 32, the length in the pipe axial direction is On the other hand, the connecting pipe 32 located near the bottom of the water is almost the total weight of the long pipe. Since only a small tensile load is applied from a certain portion, the length of the connecting pipe 32 in the axial direction is shortened. The strength of the connection can be weakened without affecting the connection. By shortening the length of the pipe, the total weight of the long pipe can be reduced, so it can be positioned near the water surface. Therefore, the tensile load applied to the connecting pipe 32 can be reduced. The length of the connecting pipe 32 in the axial direction increases as the number of times the connecting pipe 32 is repeatedly inserted increases. Therefore, it is preferable to lengthen the length continuously or stepwise.

[0078] At this time, the inner surface of the connecting pipe 32 is designed to be connected from the smallest inner diameter portion as shown in FIG. The connecting pipe 32 has a tapered surface 32a in which the inner diameter of the connecting pipe 32 continuously increases toward the pipe 34. It is preferable that

[0079] The following method can also be used to connect long pipes. (1) Covering the outer surface of the portion including one end 30a of the pipe 30 and at least one A joint having a minimum inner diameter portion is fixed to the outer surface of the pipe 30 so as to extend from the end 30a of the pipe 30. A part of the connecting tube 32 is heated. The part with the smallest inner diameter to be heated is heated at a temperature of -80°C to 50°C. Within the range of the minimum inner diameter, the inner diameter is smaller than the outer diameter of the pipe 34 to be connected. The diameter part is heated to a temperature range of 50°C to 450°C to cause thermal expansion. Therefore, the inside diameter of the smallest inside diameter portion is made larger than the outside diameter of the pipe 34 to be connected. (2) Next, the pipe 34 to be connected is inserted into the thermally expanded connecting pipe 32. (3) The temperature of the connecting pipe 32 into which the piping 34 is inserted is returned to the temperature range of -80°C to 50°C. The method of returning the temperature of the connecting pipe 32 to the temperature range of -80°C to 50°C is air cooling, water cooling, air cooling and water cooling. In the case of water cooling, for example, the pipes 30 and 34 are connected to each other. The connection part of the pipe 32 is fixed with a fixing jig, and in this state, it is immersed in seawater or cooled. After cooling by spraying a cooling medium, the fixture is removed. The inner surface of the connecting pipe 32 is oriented from the smallest inner diameter portion toward the side of the pipe 34 to be connected. The inner diameter of the tube 32 has a tapered surface 32a that continuously expands to the open end of the connecting tube 32.

[0080] Furthermore, in the above-mentioned pipe connecting method, the pipe 34 to be connected is a connecting pipe that has been thermally expanded. Before being inserted into the pipe 32, the outer diameter of the pipe 34 including the end is cooled to a temperature of less than -80°C. At this time, it is preferable to heat the connecting pipe 32 and the pipe 34 to be connected. It is preferable that the temperature difference after cooling of the portion including the end is set to 50°C to 400°C.

[0081] As shown in FIG. 8, the inner cross-sectional shape of the connecting pipe 32 is elliptical. The cross section of the outer surface of the pipe is also an ellipse. When inserting the pipe 34 into the expanded connecting pipe 32, the minor axis of the ellipse of the pipe 34 is oriented in the same direction as the minor axis of the ellipse of the connecting pipe 32. It is preferable to insert the pipe 34 in the direction of the minor axis of the circle. Therefore, the rotational deviation about the tube axis direction X with respect to the light emitting element 32 can be suppressed.

[0082] In addition, before the pipe 34 to be connected is inserted into the connecting pipe 32, the inner surface of the connecting pipe 32 is cut. The surface shape is a perfect circle, and the cross section of the outer surface of the pipe 34 to be connected is also a perfect circle. After the pipe 34 to be connected is inserted into the connecting pipe 30, the connecting pipe 34 and the pipe 34 are aligned perpendicular to the pipe axis direction X. Alternatively, a compressive stress may be applied from the outside in the direction of the connection of the pipe 34 to form an ellipse. Rotational deviation around the tube axis with respect to the tube 32 can be suppressed.

[0083] 9(a) and (b) are diagrams for explaining an outline of a pipe connecting device for carrying out a pipe connecting method according to one embodiment. This is a diagram. In the example shown in FIGS. 9(a) and 9(b), the connecting pipe 32 is heated by a heat treatment device 52. The portion including the end of the pipe 34 is cooled using a heat treatment device 54, and then the heat treatment device 56 is used to This is an example of cooling the connecting pipe 32 after the pipe 30 and the pipe 34 are connected. The pipe 34 is called the connecting pipe 34, and the pipe 30 to which the pipe 34 is connected is called the connected pipe 30. cormorant. The heat treatment device 56 is, for example, a device for spraying a heating medium or a device for irradiating heat rays such as infrared rays. It is.

[0084] The pipe connection device 40 is grounded, for example, on the ocean where there is a lot of rolling, for example, on a ship. The connecting device 40 includes a connecting pipe gripping portion 46, a connecting pipe gripping portion 50, a moving mechanism 42, and a heat The moving mechanism 42 is controlled by a control device (not shown). The connected pipe gripping portion 46 is configured to move along the support 42a by the control. The connecting pipe gripping portion 46 is connected to the pillar 42a via an arm 44. The connection pipe gripping portion 50 is configured so that it can be freely controlled to grip or not grip the support 42a. The connection pipe gripping portion 50 is connected to the outer surface of the pipe 34 via the arm 48. The connected pipe gripping portion 46 and the connecting pipe gripping portion 50 are configured so that gripping and non-gripping can be freely controlled. For example, a hydraulic gripping mechanism or a pneumatic gripping mechanism is used.

[0085] The connected pipe gripping portion 46 is configured to grip the connected pipe 30 in an upright position. do. The connecting pipe gripping portion 50 is provided above the connected pipe gripping portion 46 and has the connecting pipe 34 vertically connected thereto. The connection pipe gripping portion 50 is configured to grip, for example, one of the connection pipes 34. While one end is suspended in mid-air by a crane or the like, the vicinity of the other end (the lower end) is grasped. The moving mechanism 42 moves the connection pipe gripping part 5 so as to bring the end of the connection pipe 34 closer to the connection pipe 32. 0 is configured to move relative to the connected pipe gripping portion 46. The heat treatment devices 52, 54, and 56 are connected to each other by a connecting pipe 34 and a connected pipe 30. A process of heating the smallest inner diameter portion of the tube 32 to thermally expand it, and cooling the end of the connecting pipe 34 to The connecting pipe 34 is configured to perform at least one of the processes of reducing the outer diameter of the end of the connecting pipe 34.

[0086] The heat treatment device 52 heats the minimum inner diameter portion of the connecting pipe 32 at a temperature higher than 50° C., for example, 450° C. The heat treatment device 54 is configured to heat the end of the connecting pipe 34 to a temperature of, for example, 1000° C. The heat treatment device 56 is configured to cool the connecting pipe 32 to a temperature of, for example, less than -80°C. It is configured to return the temperature of the inner diameter portion to a temperature of, for example, -80°C to 50°C.

[0087] As shown in FIG. 9(a), the connecting pipe 32 is heated by a heat treatment device 52, and the end of the connecting pipe 34 is From the state where the part including the above is cooled by the heat treatment device 54, as shown in FIG. 9(b), 42, the connecting pipe gripping portion 50 descends to the connected pipe gripping portion 46, The portion including the end of the pipe 34 is inserted into the connecting pipe 32. Then, the heat treatment device 56 By cooling the connecting pipe 32, the inner diameter of the connecting pipe 32 shrinks, and the connecting pipe 32 tightens the connecting pipe 34. As a result, the connected pipe 30 and the connecting pipe 34 are connected via the connecting pipe 32. It is possible. In this manner, in a state where the connecting pipe 30 and the connected pipe 34 are installed upright, Since the pipe 34 can be connected, the piping can be easily connected even on the ocean where there is a lot of rolling, for example, on a ship. The riser pipe can be easily extended toward the seabed while the work is being performed.

[0088] At this time, the gripping contact area of ​​the connection pipe gripping portion 50 that contacts and grips the connection pipe 34 is The connecting pipe gripping portion 46 has a gripping contact area larger than the gripping contact area of ​​the connecting pipe 30 that contacts and grips the connecting pipe 30. is preferred. FIG. 10 is a diagram showing an example of a pipe connection device 40 according to an embodiment. The connecting pipe gripping portion 50a contacts and grips the connecting pipe 34. The gripping portion 46 is larger than the gripping portion that contacts and grips the connected pipe 30. The gripping contact area of ​​the pipe gripping portion 50a is larger than the gripping contact area of ​​the connected pipe gripping portion 46. The arm 48a that connects the connection pipe gripping portion 50a and the moving mechanism 42 has a connection pipe (not shown). An orientation adjustment mechanism is provided for adjusting the orientation of the pipe gripping portion 50a with respect to the pipe axis direction of the connected pipe 30. The orientation of the connection pipe gripping portion 50a can be adjusted by the orientation adjustment mechanism. The pipe axis direction of the connecting pipe 34 can be made to coincide with the pipe axis direction of the connected pipe 30. This allows the connection pipe 34 to be smoothly inserted into the connection pipe 32. However, even if the orientation of the connection pipe gripping portion 50 shown in FIG. 9(a) is appropriate, The gripping portion 50 does not grip the connection pipe 34 properly, and the axial direction of the connection pipe 34 is When the connecting pipe 34 is held in a state where it is slightly inclined with respect to the axial direction of the pipe 30, For this reason, the gripping contact area of ​​the connecting pipe gripping portion 50a is set to be larger than that of the connected pipe gripping portion 46. By making it larger than the gripping contact area, it is possible to prevent the connection pipe 34 from being gripped at an angle. Therefore, the orientation of the connection pipe gripping portion 50a, which has a large gripping contact area, can be appropriately adjusted. As a result, the axial direction of the connected pipe 34 can be aligned with the axial direction of the connected pipe 30. do.

[0089] FIG. 11 is a diagram showing an example of a pipe connection device according to an embodiment. The device 40 includes a tubular diameter expanding member 60. The tubular diameter expanding member 60 is extended toward the connection pipe gripping portion 50. The tubular expanded portion 60 is arranged to cover the outer periphery of the connecting pipe 32. By providing the connecting pipe 34 with the connecting pipe 32, the tubular expanding member 60 The connection pipe 34 can be smoothly guided to the connection pipe 32. Since the pipe 34 is held in an upright position, the opening of the connection pipe 34 is aligned with the opening of the connection pipe 32. Therefore, when the connection pipe gripping portion 50 is lowered, the tubular It can reach the opening of the connecting pipe 32 by being guided by the diameter expanding member 60 .

[0090] FIG. 12 is a diagram showing an example of a pipe connection device 40 according to an embodiment. In the example shown in FIG. The connection pipe gripping parts 50b, 50c are connected to the moving mechanism 42 via the arms 48b, 48c. The total area of ​​the gripping portion of the connecting pipe 34 that is gripped by the connecting pipe gripping portion 46 is The area of ​​the gripping portion that contacts and grips the connected pipe 30 is larger than that of the gripping portion. The connection pipe 3 is connected to the connection pipe 3 by adjusting the orientation of the connection pipe gripping parts 50b and 50c using the adjustment mechanism. The pipe axis direction of the connecting pipe 30 can be aligned with the pipe axis direction of the connecting pipe 30. The connecting pipe 34 can be smoothly inserted into the connecting pipe 32.

[0091] FIG. 13 is a diagram showing an example of a pipe connecting device according to an embodiment. In the example shown in FIG. The connecting pipe gripping portion 50 and the connected pipe gripping portion 46 are provided on the opposing surfaces of the connecting pipe gripping portion 50 and the connected pipe gripping portion 46. A measurement unit that measures the presence or absence of a misalignment in the direction or position between the connecting pipe gripping portion 46 and the connecting pipe gripping portion 46. The connecting pipe gripping portion 50 and the connected pipe gripping portion 46 are provided with a mating member 62. The misalignment means that the openings of the gripping parts are not aligned in the same direction. The measurement unit 62 is a laser that irradiates the laser light L. The laser beam L is received by a photodiode 62b. Information on the position of the laser light L received by the electrode 62b on the opposing surface of the connected pipe gripping portion 46 A processing device (not shown) receives the output signal and controls the laser light L It is determined whether the irradiation position of the target is in the target position. It is possible to determine whether or not there is any positional deviation. In FIG. 13, the measurement units 62 are provided at two locations, but they may be provided at three or more locations. Thus, the presence or absence of the above-mentioned deviation in direction or position can be accurately checked.

[0092] If there is a deviation in the direction or position, the above-mentioned direction adjustment mechanism can be used to adjust the direction of the connecting pipe. The orientation of the gripping portion 50 is adjusted, or a position adjustment mechanism (not shown) provided on the arm 48 is used. The connection pipe gripping portion 50 is driven to adjust the position of the connection pipe gripping portion 50. The opening of the connecting pipe 34 is aligned with the axial direction of the connected pipe 30, and the opening of the connecting pipe 34 is aligned with the axial direction of the connected pipe 30. It can be positioned in the correct position relative to the 0 opening. Instead of the photodiode 62b, it is possible to determine whether the irradiation position of the laser light L is at the target position. A target marker can be used to visually judge the position of the laser beam L. If the marker position is not aligned, the orientation adjustment function can be manually adjusted as described above. The mechanism or position adjustment mechanism can be adjusted.

[0093] The inner diameter surface of the connecting pipe 32 and the outer diameter surface of the upper end of the connected pipe 30 are machined to a certain tolerance. However, the inner diameter of the connecting pipe 32 and the outer diameter of the connected pipe 30 are within the tolerance. Fluctuations in the diameter are inevitable. Also, due to the rolling and pitching of the ship, The geometric center of the lower end surface of the connecting pipe 32 to be connected and the geometric center of the uppermost end surface of the connected pipe 30 A slight misalignment of the geometric center is inevitable. The geometric center of the lower end surface of the connecting pipe 34 and the geometric center of the uppermost end surface of the connecting pipe 32 are slightly different from each other. Misalignment is unavoidable.

[0094] Even in a situation where such a positional deviation is unavoidable, the connecting pipe 32 and the connected pipe 30 can be Alternatively, as a preferred embodiment for smoothly connecting the connection pipe 34 and the connection pipe 30, 14 or 15. In these configurations, the connecting pipe 32 is connected When connecting the pipe 30 or when connecting the connecting pipe 34 to the connecting pipe 32, Rotation is applied to the connecting pipe 32 or the connecting pipe 34 along the circumferential direction. The continuation can be carried out smoothly.

[0095] FIG. 14 is a diagram showing an example of a pipe connection device according to an embodiment. As shown in FIG. The pipe gripping portion 70 grips the outer periphery of the connecting pipe 32 before connection so as to cover it, and rotates at a rate of more than 0 to 1 revolution per second. The connecting pipe 32 is rotated at the following speed while being held by the connected pipe holding portion 46. It is preferable to provide the pipe connecting device 40 with a mechanism for moving the pipe connecting device 40 to the uppermost end of the connected pipe 30. That is, the pipe connection device 40 connects and fixes the connecting pipe 32 to the connected pipe 30. In order to do so, a connecting pipe gripping portion is provided which grips the outer periphery of the connecting pipe 32 so as to cover it and connect it to the connected pipe 30. The connecting pipe gripper 70 moves to the top end of the connected pipe 30 and grips the connecting pipe 32. When connecting to the connected pipe 30, the outer periphery of the connecting pipe 32 is rotated in the circumferential direction. It is preferable to provide a rotation mechanism that imparts a rotation speed of more than 1 rotation / second to the connecting pipe 32. The rotation mechanism may be, for example, a rotating mechanism in which the portion of the connecting pipe gripping portion 70 that comes into contact with and grips the connecting pipe 32 is rotated. The roller surface of the roller is rotated by a driving mechanism (not shown).

[0096] 15 is a diagram showing an example of a pipe connection device according to an embodiment. The connection pipe gripping portion 71 is provided on the moving mechanism 42 shown in FIG. The pipe 34 is gripped so as to cover the outer periphery thereof, and the moving mechanism 42 shown in FIG. When the connecting pipe 34 is moved to the top end of the connecting pipe 32 and connected to the connecting pipe 32, the connecting pipe 34 rotates by more than 0 to 1. It is preferable to provide a rotation mechanism that imparts a rotation speed of 1 / sec or less to the connection pipe 34. That is, the connection pipe gripping portion 71 grips the outer periphery of the connection pipe 34 before connection so as to cover it, and further The connecting pipe gripping portion 71 is moved by the moving mechanism 42 shown in FIG. When the connecting pipe 34 is connected to the connecting pipe 32 by bringing it close to the holding portion 46, the outer circumference of the connecting pipe 34 A rotation speed of more than 0 and not more than 1 rotation / second is applied to the connecting pipe 34 so as to rotate in the circumferential direction. It is preferable that the connecting pipe gripping portion 71 is provided with a rotation mechanism. The portion that comes into contact with and grips the connecting pipe 34 is the roller surface of the rotating roller. It is rotated by a drive mechanism not shown.

[0097] As described above, the pipe connection device 40 is configured to erect the connecting pipe 30 and the connected pipe 34. Since the connecting pipe 30 and the connected pipe 34 can be connected in this state, it is possible to For example, the process of extending the riser pipe toward the seabed can be easily performed while connecting the pipes on board the ship. It can be done easily.

[0098] The pipe connection mechanism, the pipe connection method, and the pipe connection device of the present invention have been described in detail above. However, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. Of course, various improvements and modifications may be made. [Explanation of symbols]

[0099] 10. Lift System 12. Drilling Ship 20 Riser Pipe 22 Lifting device 26 Collection device 28 Processing Equipment 30,34 Piping 30a,34a edge 30b, 32a, 34b Tapered surface 32 Connecting pipe 35 Coolant piping 35a, 36a Arms 35b, 36b Rotating body 36 Heating medium piping 40 Pipe connection device 42 Moving mechanism 42a post 44, 48, 48a, 48b, 48c Arms 46 Connected pipe grip part 50 Connected pipe grip part 50a Connection pipe gripping part 52 Heat treatment equipment (heating between 50℃ and 450℃) 54 Heat treatment equipment (cooled to below -80℃) 56 Heat treatment equipment (heating temperature between 50℃ and 450℃ is returned to -80℃~50℃) 60 Tubular expanding member 62 Measurement Unit 62a Laser irradiation device 62b Photodiode 70 Connection pipe grip 71 Connection pipe gripping part

Claims

1. A piping connection mechanism for a long pipe, comprising: A plurality of pipes, A first pipe; a second pipe connected to the first pipe; A plurality of pipes having the a connecting pipe having a minimum inner diameter portion, the connecting pipe covering an outer surface of a portion including an end of the first pipe on a side connected to the second pipe, and fixed to an outer surface of a connecting portion between the first pipe and the second pipe so as to extend from the end of the first pipe toward the second pipe; the minimum inner diameter portion of the connecting pipe has an inner diameter dimension smaller than the outer diameter of the second pipe in a temperature range of -80°C to 50°C, and the inner diameter dimension is set so that by heating the minimum inner diameter portion of the connecting pipe to thermally expand it in a temperature range of more than 50°C and not more than 450°C, the inner diameter dimension becomes larger than the outer diameter of the second pipe so that the second pipe can be fitted into the connecting pipe; A pipe connection mechanism characterized in that the connecting pipe reinforces the multiple pipes against large lateral forces, and the weight of the entire multiple pipes is adjusted by adjusting the length of the connecting pipe depending on the magnitude of the lateral force.

2. 2. The pipe connection mechanism according to claim 1, wherein the connecting pipe is made of a tempered martensitic steel, an austenitic stainless steel, or an austenitic-ferritic stainless steel.

3. 3. The pipe connection mechanism according to claim 1, wherein the outer surface of the second pipe has a tapered surface whose outer diameter continuously decreases toward an end on a side that fits into the connecting pipe.

4. The piping connection mechanism according to any one of claims 1 to 3, wherein the inner surface of the connecting pipe has a tapered surface in which the inner diameter of the connecting pipe continuously increases from the minimum inner diameter portion toward the second piping side.

5. 5. The pipe connection mechanism according to claim 3, wherein a ratio of the length of the tapered surface along the pipe axis direction of the connecting pipe to the pipe thicknesses of the first pipe and the second pipe is 1 to 20.

6. The piping connection mechanism of claim 3, wherein an outer diameter of at least a portion of the tapered surface is larger than an inner diameter of the connecting pipe at an opposing position in a temperature range of -80°C to 50°C, and an outer diameter of the remaining portion of the tapered surface is equal to or smaller than the inner diameter of the connecting pipe at a temperature range of -80°C to 50°C, and wherein heating of the connecting pipe causes the inner diameter of the connecting pipe at the opposing position to be larger than the outer diameter of the at least a portion of the tapered surface.

7. The pipe connection mechanism of claim 4, wherein an inner diameter of at least a portion of the tapered surface is smaller than an outer diameter of the second pipe at the opposing position in a temperature range of -80°C to 50°C, and an inner diameter of the remaining portion of the tapered surface is equal to or larger than the outer diameter of the second pipe at a temperature range of -80°C to 50°C, and wherein heating of the connecting pipe causes the inner diameter of at least a portion of the tapered surface to become larger than the outer diameter of the second pipe at the opposing position.

8. The pipe connection mechanism according to any one of claims 1 to 7, wherein the carbon equivalent of the first pipe and the second pipe is 0.43 mass% or more.

9. The tensile yield strength of the first pipe and the second pipe is 555 [N / mm ２ 9. The pipe connection mechanism according to claim 1, wherein the number of the connecting members is equal to or larger than the number of the connecting members.

10. The long pipe is configured to connect at least ten or more of the first pipes and the second pipes by the connecting pipes, The piping connection mechanism according to any one of claims 1 to 9, wherein the mass of each of the first piping and the second piping is 100 kg to 10,000 kg, and the pipe thickness of each of the first piping and the second piping is 5 mm to 100 mm.

11. The pipe connection mechanism according to any one of claims 1 to 10, wherein the linear expansion coefficient of the connecting pipe between 50°C and 450°C is 20% or more higher than the linear expansion coefficient of the pipe between -80°C and 50°C.

12. The pipe connection mechanism according to any one of claims 1 to 11, wherein in addition to heating the minimum inner diameter portion of the connecting pipe, a portion including the end of the second pipe is cooled to a temperature of less than 0°C to shrink the outer diameter of the portion, so that the inner diameter dimension is set to be larger than the outer diameter of the second pipe so that the second pipe can be fitted into the connecting pipe, and a temperature difference between the heating temperature of the minimum inner diameter portion and the cooling temperature of the portion including the end of the second pipe is set to be 50°C to 400°C.

13. 13. The pipe connection mechanism according to claim 1, wherein the pipe cross-sectional shape of the inner surface of the connecting pipe is an ellipse, and the pipe cross-sectional shape of the outer surface of the second pipe is also an ellipse.

14. The pipe connection mechanism according to claim 13 , wherein a ratio of a minor axis of the ellipse to a major axis of the ellipse is equal to or greater than 0.9 and less than 1.

0.

15. A method for connecting long pipes, comprising the steps of: a step of heating a part of a connecting pipe having a minimum inner diameter portion, the connecting pipe having a minimum inner diameter portion fixed to an outer surface of the first pipe in advance so as to cover an outer surface of a portion including one end of the first pipe and extend from at least one end of the first pipe, the minimum inner diameter portion having an inner diameter dimension smaller than an outer diameter of a second pipe connected to the first pipe in a temperature range of -80°C to 50°C, and heating the minimum inner diameter portion in a temperature range of more than 50°C to 450°C to thermally expand the minimum inner diameter portion, thereby making the inner diameter dimension of the minimum inner diameter portion larger than the outer diameter of the second pipe; inserting the second pipe into the thermally expanded connecting pipe; and returning the temperature of the connecting pipe to a temperature range of −80° C. to 50° C. after the second pipe is inserted. The step of inserting into the connecting pipe is repeated; A pipe connection method characterized in that the connecting pipe reinforces the multiple pipes against large lateral forces, and the weight of the entire long pipe is adjusted by adjusting the length of the connecting pipe depending on the magnitude of the lateral force.

16. 16. The pipe connecting method according to claim 15, wherein the connecting pipe is made of tempered martensitic steel, austenitic stainless steel, or austenitic-ferritic stainless steel.

17. the step of making the inner diameter dimension of the minimum inner diameter portion larger than the outer diameter of the second pipe includes heating the connecting pipe from an outer surface side; 17. The pipe connecting method according to claim 15, wherein the step of returning the temperature of the connecting pipe to the temperature range of -80°C to 50°C includes cooling the connecting pipe from an outer surface side.

18. The pipe connecting method according to any one of claims 15 to 17, further comprising a step of cooling the second pipe to a temperature of less than -80°C to shrink an outer diameter of a portion including an end of the second pipe before inserting the second pipe into the thermally expanded connecting pipe.

19. 19. The piping connection method according to claim 18, wherein the step of making the outer diameter of the second pipe smaller than the inner diameter dimension of the minimum inner diameter portion includes: inserting a cooling medium pipe into the inside of the second pipe, guiding a cooling medium pipe along an inner surface of the second pipe to the end of the second pipe, and supplying cooling medium from the cooling medium pipe to the inner surface of the end, thereby cooling the end of the second pipe from the inner surface side of the pipe.

20. 19. The piping connection method according to claim 18, wherein the step of making the outer diameter of the second pipe smaller than the inner diameter dimension of the minimum inner diameter portion includes supplying a cooling medium to the end of the second pipe from an outer surface side of the second pipe.

21. The piping connection method according to any one of claims 18 to 20, wherein the step of returning the portion including the end of the second piping to a temperature range of -80 °C to 50 °C includes heating the end of the second piping from the inner surface side of the second piping by inserting a heating medium piping into the inside of the second piping and guiding the heating medium piping along the inner surface of the second piping to the end of the second piping and supplying the heating medium from the heating medium piping to the inner surface of the end.

22. The pipe connecting method according to any one of claims 15 to 21, wherein when the second pipe is inserted into the thermally expanded connecting pipe, one end of the second pipe having a tapered surface on its outer surface, the outer diameter of which is continuously reduced up to the end of the second pipe, is inserted into the connecting pipe.

23. The pipe connecting method according to any one of claims 15 to 21, wherein the inner surface of the connecting pipe has a tapered surface in which the inner diameter of the connecting pipe continuously increases from the minimum inner diameter portion toward the second pipe side.

24. The pipe connecting method according to any one of claims 15 to 23, wherein a temperature difference between a heating temperature of the connecting pipe and a temperature after cooling of a portion including the end of the second pipe is set to 50°C to 400°C.

25. The cross-sectional shape of the inner surface of the connecting pipe is an ellipse, and the cross-sectional shape of the outer surface of the second pipe is also an ellipse, The pipe connecting method according to any one of claims 15 to 24, wherein when the second pipe is inserted into the thermally expanded connecting pipe, the second pipe is inserted such that the orientation of the minor axis of the ellipse of the second pipe is aligned with the orientation of the minor axis of the ellipse of the connecting pipe.

26. A pipe cross-sectional shape of an inner surface of the connecting pipe before the second pipe is inserted into the connecting pipe is a perfect circle, and a pipe cross-sectional shape of an outer surface of the second pipe is also a perfect circle; The pipe connecting method according to any one of claims 15 to 25, further comprising a step of: after inserting the second pipe into the connecting pipe, applying compressive stress from the outside of the connecting pipe and the connected second pipe in a direction perpendicular to the pipe axial direction to form an ellipse.

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