KR102334359B1 - Double walled gas pipes - Google Patents

Abstract

The present invention provides a double walled pipe for fuel supply, comprising: a plurality of main modules installed in a form of being side by side connected to each other; a supply side module coupled to an end in a fuel supply side direction in the double walled pipe formed by allowing the main modules to be side by side connected to each other; a discharge side module coupled to an end in a fuel discharge side direction in the double walled pipe formed by allowing the main modules to be side by side connected to each other; and a cylinder distribution module, which is a tube coupled one by one to each distribution side flange formed in the main module, wherein the cylinder distribution module and the main module are provided at each one cylinder one by one such that parts can be supplied in perfect order without difficulty due to supply of parts from production to installation and maintenance of the double walled pipe for fuel supply, and the airtight structure of an internal tube, hard to be properly implemented because of extreme complication, can be very conveniently implemented rather than in conventional welding.

Description

Double walled gas pipes for fuel supply

The present invention relates to a double pipe for fuel supply.

Conventional ships are powered by diesel engines, which are more thermally efficient than gasoline. However, unlike ordinary ships, LNG carriers have a natural gas evaporation problem (Boil Off Gas, BOG). is mostly

The evaporated natural gas undergoes any one of reliquefaction, consumption as fuel, or combustion. In the early stages of LNG carriers, a steam turbine engine was adopted, and the evaporated natural gas was used as fuel for the steam turbine. Later, a dual fuel diesel electric engine system (DFDE), which is more efficient than a steam turbine engine, was used. , a dual fuel diesel engine is operated with evaporated natural gas, and the propeller motor is driven with the generated power. As a compressor for fuel processing, it is possible to re-liquefy surplus natural gas, making it possible to operate an LNG carrier with higher efficiency than before.

A dual fuel engine used in an LNG carrier has a plurality of cylinders arranged in a line as shown in FIG. 1, and one double pipe for fuel supply is disposed along the arrangement direction of the plurality of cylinders, and from one double pipe for fuel supply Connecting pipes as many as the number of cylinders are installed for each cylinder to connect the cylinder and the double pipe for fuel supply.

The double pipe for fuel supply consists of an inner tube through which natural gas fuel flows, and an outer tube surrounding the inner tube, as shown in FIG. 3b . When natural gas is used as fuel, the double pipe structure prevents the diffusion of natural gas by double guaranteeing the airtightness of natural gas when a portion where natural gas leaks from the inner pipe occurs.

However, since the double pipe for fuel supply has a double pipe structure in which an inner pipe and an outer pipe are combined, it is not easy to weld the inner pipe when welding is required at the middle joint part, so the intermediate joint process can be quite difficult, and the airtightness as possible as possible To ensure that, when the intermediate joint is closely adhered, precise surface grinding must be made on the flange end surface formed at the joint. Also, when a defect in the welded part occurs in the inner pipe and maintenance is required, only the defective part is It is difficult to manufacture replacement pipes designed to be replaceable in advance, which may cause significant disruption in the supply of parts for maintenance.

In addition, when performing welding for sealing inside the double pipe, there is a risk of safety accidents such as suffocation of workers, and the work is difficult because the work must be done in a narrow and dark space.

Therefore, there is a need to develop a technology for a double pipe for fuel supply that can solve the problem of supply and demand of parts, the need to prevent fuel leakage at the joint of the inner pipe, and the risk and difficulty of work.

Laid-Open Patent Publication No. 10-2016-0026413 (published date: March 09, 2016)

Accordingly, the present invention prevents a situation in which difficulties arise because specific parts are not supplied from manufacturing to installation and maintenance of a double pipe for fuel supply, and unnecessary inventory due to supply and demand imbalance is not accumulated, and also, the internal pipe is manufactured by conventional welding. An object of the present invention is to provide a double pipe for fuel supply having a structure in which the airtight structure of the connection part capable of preventing leakage, which is significantly more reliable than the connected structure, can be made in a much simpler and safer process than welding.

The double pipe for fuel supply according to the present invention for achieving this object is a double pipe for fuel supply consisting of an external pipe and a fuel supply pipe built into the external pipe. A plurality of radially symmetrical bolt holes are formed in one to form a bolt body fastening flange to which the bolt body is fastened, and a plurality of radially symmetrical bolt holes are formed in the other one of both ends in the longitudinal direction to fasten the bolt head. A head fastening flange is formed, and a distribution-side flange is formed in a predetermined portion between both ends in the longitudinal direction so that a pipe for supplying fuel to the cylinder is coupled, and a plurality of main modules are installed in parallel to each other, and the main module; When a plurality of modules are connected in parallel, they are coupled to either end of one of the outermost main modules on both sides, and a flange of a shape corresponding to any one of the bolt body fastening flange or the bolt head fastening flange is attached to the part in contact with the main module. is coupled to the end of the fuel discharge side in the double pipe formed by connecting the supply-side module and the plurality of main modules in parallel, and in a portion in contact with the main module, either the bolt head fastening flange or the bolt body fastening flange It consists of a discharge-side module having a flange corresponding to one formed therein, and a cylinder distribution module that is coupled to each of the distribution-side flanges formed on the plurality of main modules, and is a double pipe connecting the distribution-side flange and the engine cylinder, wherein the One cylinder distribution module and one main module are provided for each cylinder.

Here, the main module, the supply-side module, the discharge-side module, and the cylinder distribution module are preferably manufactured by 3D printing.

In addition, the main module preferably has an internal fuel supply pipe and an external pipe constituting the main module connected to each other at the bolt body fastening flange and the bolt head fastening flange formed at both ends of the main module to fix the position of the internal fuel supply pipe, and the fuel supply pipe A sleeve having a predetermined thickness is formed in a further extending form on either side of both ends, and the outer diameter of the sleeve corresponds to the inner diameter of the adjacent fuel supply pipe.

In this case, an expansion curved surface is formed on the surface of the sleeve or an inner surface of the fuel supply pipe of the adjacent main module that is in close contact with the surface of the sleeve, and an expansion curved surface that is preferably expanded toward the other one is formed on the other one, and the other has the same curvature as the expansion curved surface. A curved surface formed by

In this case, the length of the section in which the expansion curved surface is formed is preferably equal to or greater than the length of the section in which the curved surface is formed.

In addition, a groove is formed on the expansion curved surface along the circumferential direction of the sleeve at a predetermined position. Preferably, the side cross-sectional shape of the groove is formed in an obtuse shape at a point close to the sleeve side among the two points where the groove ends, and at the sleeve side The distant point can be formed in the form of an acute angle or a wedge shape.

And a straight section is preferably formed by a certain interval between the starting point of the sleeve and the starting point of the expansion curve, a buffer member is installed in the straight section, and the length of the section in which the expansion curve is formed is a curved surface It is formed larger than the length of the formed section.

The double pipe for fuel supply according to the present invention prevents a situation in which difficulties occur because specific parts are not supplied until manufacturing, installation, and maintenance of the double pipe for fuel supply, and unnecessary inventory due to supply and demand imbalance is not accumulated, and also There is an effect that the airtight structure of the connection part that can prevent leakage, which is significantly more reliable than the structure in which the inner pipe is connected by welding, can be made in a much simpler and safer process than welding.

1 is a perspective view of a dual fuel diesel engine installed with a double pipe for fuel supply;
2a is a perspective view of a double pipe for fuel supply according to the present invention;
Fig. 2b is a plan view of Fig. 2a;
Fig. 2c is a side view of Fig. 2b;
Fig. 2d is a cross-sectional view of Fig. 2b;
Fig. 3a is an enlarged view simplified to Fig. 2b;
Fig. 3b is a cross-sectional view of Fig. 3a;
Figures 4a and 4b are cross-sectional views showing a modified embodiment of Figure 3b;
5 is a partially enlarged view of FIG. 4b;

Specific structural or functional descriptions presented in the embodiments of the present invention are only exemplified for the purpose of describing embodiments according to the concept of the present invention, and the embodiments according to the concept of the present invention may be implemented in various forms. In addition, it should not be construed as being limited to the embodiments described herein, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The double pipe 100 for fuel supply according to the present invention has an external pipe 11 and an internal pipe 12, which is a fuel supply pipe formed long along the longitudinal direction of the external pipe 11, as described in the background art section above. As fuel flows through the inner tube 12 and air flows between the outer tube 11 and the inner tube 12, the inner tube 12 distributes fuel to each cylinder for each of the plurality of engine cylinders shown in FIG. A pipe formed to prevent fuel leaking in the process of supplying from leaking to the outside by being trapped between the inner pipe 12 and the outer pipe 11, a plurality of main modules connected in parallel with each other; A plurality of supply-side modules 30 coupled to one end of the plurality of main modules 10, a plurality of main modules 10, a plurality of discharge-side modules 20 coupled to the other end, and a plurality of main modules 10 coupled one by one It is composed of a cylinder distribution module (40).

As shown in FIGS. 2A to 2C and 3A , the main module 10 is formed to have a constant length, and a plurality of radially symmetrical bolt holes are formed at either one of both ends in the longitudinal direction, to which the bolt body is fastened. A body fastening flange 14 is formed, and a plurality of radially symmetrical bolt holes are formed on the other one of both ends in the longitudinal direction to form a bolt head fastening flange 13 to which the bolt head is fastened, and between both ends in the longitudinal direction. A distribution-side flange 15 is formed at a predetermined portion so that the cylinder distribution module 40, which is a pipe for supplying fuel to the cylinder, is coupled, and a plurality of them are installed in parallel with each other.

The supply-side module 30 is coupled to an end in the fuel supply-side direction in a double pipe in which a plurality of main modules 10 are connected in parallel as shown in FIG. 3A , and is in contact with the main module 10 by a bolt. It is a pipe in which a flange of a shape corresponding to any one of the body fastening flange 14 or the bolt head fastening flange 13 is formed.

The discharge-side module 20 is coupled to an end in the fuel discharge-side direction in a double pipe formed by connecting a plurality of main modules 10 in parallel as shown in FIG. 3A, and in a portion in contact with the main module 10 It is a pipe in which a flange of a shape corresponding to any one of the bolt head fastening flange 13 or the bolt body fastening flange 14 is formed.

The cylinder distribution module 40 is coupled to each of the distribution side flanges 15 formed in the plurality of main modules 10 as shown in FIG. 3A , and connects the distribution side flange 15 and the engine cylinder shown in FIG. 1 . This is a double pipe, which corresponds to a pipe that supplies fuel to the cylinder.

As shown in FIGS. 2A to 2D , a plurality of main modules 10 are connected in parallel between the supply-side module 30 and the discharge-side module 20 . At this time, in the present invention, the main module 10 is manufactured to have a size corresponding to the distance between the cylinders so that they are arranged one for each cylinder. Accordingly, one main module 10 and one cylinder distribution module 40 are allocated to one cylinder.

As a result, the main module 10 and the cylinder distribution module 40 of exactly the same shape and size are allocated to each cylinder, unlike the conventional modular double tube, so that the main module 10 or the cylinder distribution module 40 of one cylinder side ), only the defective part can be replaced. In this case, the new parts to be replaced are all the same product with the same standard, size, and shape, so there is no need to supply and secure separate materials and stock for each part. Inventory costs for maintenance and process delays for material supply can be resolved.

Since the double pipe 100 for fuel supply also consists of an inner tube 12 and an outer tube 11, the outer tube 11 in the process of connecting the two main modules 10 can be connected by normal butt welding, The inner tube 12 may have a very difficult welding process or may be almost impossible depending on its size. In addition, even when the diameter of the inner tube 12 is large, it can be quite difficult and dangerous for an operator to perform welding directly, and as the work is difficult and difficult, the welding quality may also be problematic, so there is a risk of leakage of natural gas fuel can occur

In addition, in the conventional joint work of the double pipe for fuel supply, precise grinding of the end face was required in order for the weld face to be exactly abutted to each other while minimizing the error.

In order to solve this problem, in the double pipe 100 for fuel supply according to the present invention, at least a main module among the main module 10 , the supply-side module 30 , the discharge-side module 20 , and the cylinder distribution module 40 . (10) and the cylinder distribution module 40 are manufactured by 3D printing. Of course, more preferably, the supply-side module 30 and the discharge-side module 20 may also be manufactured by 3D printing.

When each module (10, 20, 30, 40) is all manufactured by 3D printing, due to the dimensional error that has occurred in the connection portion between each module (10, 20, 30, 40) and the connection portion between the main module (10) The problem of poor airtightness in the local area, which may occur after butt welding, can be significantly reduced. In addition, as a result of remarkably reducing the problem of dimensional defects, the process of surface polishing of the end surface, which should be preceded in the conventional seam welding process, can be omitted, and the process is greatly reduced, so that the effort and cost can be drastically reduced. In addition, when the main module 10, the supply-side module 30, the discharge-side module 20, and the cylinder distribution module 40 are manufactured by 3D technique, even if the surface is not polished, it is more Since the end face has the correct shape and dimensions, the leak prevention problem can be solved even if the inner tubes 12 , 22 , and 32 do not have to undergo welding.

However, in the present invention, a joint structure as shown in FIGS. 4A to 5 is proposed in order to fundamentally solve the leakage problem that may occur even if the end surfaces are precisely joined in this way.

In particular, the joint structure proposed in FIGS. 4A to 5 is designed so that the airtightness of the inner tubes 12 , 22 , and 32 can be thoroughly maintained without welding the inner tubes 12 , 22 , and 32 .

Specifically, as shown in Fig. 4a, between the main module 10 and the main module 10, or between the main module 10 and the remaining modules, the supply-side module 30, the discharge-side module 20, the cylinder distribution module ( When any one of 40) is joined, a sleeve 17 of a certain thickness is formed at one end in a form in which the end protrudes in a further extending direction. At this time, the outer diameter of the sleeve 17 corresponds to the inner diameter of the inner tube (12, 22, 32) of the adjacent module coupled to the portion where the sleeve 17 is formed.

Therefore, the outer diameter of the sleeve 17 is preferably the same as the inner diameter of the inner tube (12, 22, 32) of the end of the sleeve 17 is formed. This is because the diameters and shapes of the inner tubes 12, 22 and 32 in all the modules 10, 20, 30, and 40 must be the same. Therefore, as shown in Fig. 4a, the sleeve 17 is formed to have a reduced diameter compared to the inner tube 12, 22, 32. However, the outer diameter of the sleeve 17 may be formed larger than the inner diameter of the inner tube (12, 22, 32) at the end of the sleeve 17 is formed by a fine size. This is to further enhance the confidentiality effect, which will be described later. In particular, since the end of the sleeve 17 has a reduced thickness for ease of insertion as shown in FIG. 4A , the sleeve 17 is slightly larger than the inner diameter of the inner tube 12, 22, and 32. Although it can be easily inserted, the airtight effect can be further increased.

On the other hand, as shown in Fig. 4a, any one of the inner surface of the inner tube 12 of the main module 10 adjacent to the surface of the sleeve 17 or the surface of the sleeve 17 is expanded toward the other one as shown in Fig. 4A. An expansion curved surface 171 of is formed, and a curved surface 18 formed with the same curvature as the expansion curved surface 171 is formed on the other one.

As such, an expansion curved surface having the same curvature ( 171) and the curved surface 18 are formed, the area in close contact with each other is increased compared to the length of the sleeve 17 or in the circumferential direction at a certain depth, that is, linear contact in the form of a circle can occur reliably as well as mutually The problem of leakage can be significantly reduced by making the shape of the facing part curved rather than straight.

In this case, the length of the section in which the expansion curved surface 171 is formed may be equal to or greater than the length of the section in which the curved surface 18 is formed. This is because if the length of the section in which the expansion curved surface 171 is formed is smaller than the length of the section in which the curved surface 18 is formed, the contact itself between the expansion curved surface 171 and the curved surface 18 cannot be made.

In particular, in this case, when the length of the section in which the curved surface 18 is formed is shorter than the length of the section in which the expansion curved surface 171 is formed, the expansion curved surface 171 is completely on the curved surface 18 when viewed based on FIG. 4B . Since there is inevitably a portion where both sides remain even after being in close contact, the sleeve 17 inevitably receives a force in the direction of contraction toward the center, and as a reaction against this, the sleeve 17 exerts an elastic force in the direction to expand radially. have.

Therefore, since the length of the section of the expansion curved surface 171 is formed to be larger, the force for adhering the expansion curved surface 171 and the curved surface 18 is dramatically increased, so that the inner tube 12 is connected by welding even without a welding process. The leakage problem can be prevented as much as possible while maintaining more structural soundness compared to the case where it is used.

In addition, as shown in FIG. 5 , a groove 172 is formed on the expansion curved surface 171 along the circumferential direction of the sleeve 17 at a predetermined position, and the cross-sectional shape of the side surface of the groove 172 is where the groove 172 ends. Among the two points, a point close to the sleeve 17 side may be formed in an obtuse angle shape, and a point farther from the sleeve 17 side may be formed in an acute angle shape or a wedge shape.

The groove 172 is formed in a wedge shape as shown in FIG. 5, so that the wedge shape is a curved surface in the process of the expansion curved surface 171 of the sleeve 17 being pushed into the curved surface 18 of the inner tube 12 inner surface. The plastic deformation portion 181 in the form of stopping the wedge due to friction with the surface of the curved surface 18 may be generated until it is finally settled on the (18). The plastic deformation part 181 is similar to the principle that the fork crane is formed in the form of a lump at the lower shovel end of the fork crane as the soil gradually accumulates as it passes by scraping the soil floor.

Of course, since the plastic deformation that can occur on the surface of the curved surface 18 occurs with an extremely fine thickness, the plastic deformation portion 181 shown in FIG. 5 is quite exaggerated, but in particular, the expansion curved surface 171 section Since the curved surface 18 is formed to be larger than the section, when the expansion curved surface 171 is in close contact with the curved surface 18 and is pressed by a large force, the plastic deformation portion 181 may be minutely generated. .

When this plastic deformation part 181 is generated even slightly, residual stress RF to return to the shape before deformation is generated. As a result of the residual stress (RF) generated as shown in FIG. 5, the wedge shape of the plastically deformed portion 181 and the groove 172 is in close contact with each other, and the inner tubes 12, 22, 32 are connected by conventional welding. A more robustly leak-proof connection structure is made.

On the other hand, as shown in FIG. 5, a straight section is formed by a predetermined interval between the starting point of the sleeve 17 and the starting point of the expansion curved surface 171, and a compression sealing material 173 is installed in the straight section, The length of the section in which the expansion curved surface 171 is formed may be formed to be larger than the length of the section in which the curved surface 18 is formed.

When the section of the expansion curved surface 171 is formed to be longer than the section of the curved surface 18 , as described above, the areas before and after the expansion curved surface 171 are not in contact with each other may occur. At this time, when the compression sealing material 173 is installed at the portion where the sleeve 171 starts as shown in FIG. 5 , a close leakage preventing structure may be formed even in a portion not in contact with each other. In this case, the compression sealing material 173 may be a material having good corrosion resistance and heat resistance and constant elasticity, such as silicon.

The present invention described above is not limited by the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes can be made within the scope without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

RF : Residual stress 1 : Dual fuel diesel engine
10: main module 11,21,31: outer tube
12,22,32: inner tube 13,23: bolt head fastening flange
14,34: bolt body fastening flange 15: distribution side flange
16: air passage 17: sleeve
18: curved surface 20: discharge side module
30: supply side module 40: cylinder distribution module
100: double pipe for fuel supply 171: expansion curved surface
172: groove 173: compression sealing material
181: plastic deformation part

Claims (7)

A double pipe for fuel supply comprising an external pipe and a fuel supply pipe built into the external pipe,
A member in the form of a double tube having a certain length, a plurality of radially symmetrical bolt holes are formed at either end in the longitudinal direction to form a bolt body fastening flange to which the bolt body is fastened, and at the other one of both ends in the longitudinal direction A plurality of radially symmetrical bolt holes are formed to form a bolt head fastening flange to which the bolt head is fastened, and a distribution-side flange is formed at a predetermined portion between both ends in the longitudinal direction so that a pipe for supplying fuel to the cylinder is coupled, and a plurality of a main module installed in a form connected to each other in parallel;
When a plurality of the main modules are connected in parallel, they are coupled to one end of one of the outermost main modules on both sides, and a portion in contact with the main module corresponds to either the bolt body fastening flange or the bolt head fastening flange. a supply-side module on which a flange is formed;
A plurality of main modules are coupled to an end in a fuel discharge side direction in a double pipe formed by being connected in parallel, and a flange of a shape corresponding to any one of the bolt head fastening flange or the bolt body fastening flange at a portion in contact with the main module The discharge-side module is formed; and,
A cylinder distribution module coupled to each of the plurality of distribution side flanges formed on the main module, a double pipe connecting the distribution side flange and the cylinder, which is a tube for supplying fuel to the cylinder;
The cylinder distribution module and the main module are provided one for each cylinder,
The main module, the supply-side module, the discharge-side module, and the cylinder distribution module are manufactured by 3D printing,
In the main module, the internal fuel supply pipe and the external pipe constituting the main module are integrally connected to each other at the bolt body fastening flange and the bolt head fastening flange formed at both ends of the main module, so that the position of the internal fuel supply pipe is fixed,
At either end of the fuel supply pipe, a sleeve of a certain thickness is formed in a further extended form,
The outer diameter of the sleeve corresponds to the inner diameter of the adjacent fuel supply pipe,
On either one of the inner surfaces of the fuel supply pipe of the adjacent main module that is in close contact with the surface of the sleeve or the sleeve, an expansion curved surface is formed that expands toward the other one, and the other is curved formed to have the same curvature as the expansion curved surface. face is formed
A groove is formed at a predetermined position along the circumferential direction of the sleeve on the expansion curved surface, and the side cross-sectional shape of the groove is formed in an obtuse shape at a point close to the sleeve side among the two points where the groove ends, and an acute angle at a point far from the sleeve side A double pipe for fuel supply for each cylinder, characterized in that it is formed in a shape or wedge shape. delete delete delete According to claim 1,
A double pipe for fuel supply for each cylinder, characterized in that the length of the section in which the expansion curved surface is formed is equal to or greater than the length of the section in which the curved surface is formed. delete According to claim 1,
A straight section is formed by a predetermined interval between the starting point of the sleeve and the starting point of the expansion curve, a compression sealing material is installed in the straight section, and the length of the section in which the expansion curve is formed is the length of the section in which the curved surface is formed A double pipe for fuel supply for each cylinder, characterized in that it is formed larger than that.

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