Patent Publication Number: US-10308326-B2

Title: LNG tank container transport ship, and transport method using same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Korean Patent Application 10-2015-0029870, filed on Mar. 3, 2015, the entire disclosure of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to an LNG tank container transport ship and a transportation method using the same. 
     BACKGROUND ART 
     Natural gas is usually supplied to consumers by the following two methods: a method in which natural gas is directly supplied to consumers through natural gas pipelines and a method in which liquefied natural gas (LNG) is supplied to consumers by a tanker truck. The latter is commonly employed to supply natural gas to a remote site where natural gas pipelines are not installed. 
     However, this method has a problem in that it is necessary to install a separate stationary storage tank at the remote site and to periodically charge the stationary storage tank with LNG. 
     At present, the only way to supply LNG to an island area is to use an LNG bunker shuttle or LNG tank container. However, this method has a problem in that there is no ship dedicated to transporting LNG tank containers, and in that installation of dedicated cargo handling facilities in a dock and port maintenance are required, making the transportation process complicated and causing cost increase and deterioration in transport reliability. 
     DISCLOSURE 
     Technical Problem 
     It is an aspect of the present invention to provide an LNG tank container transport ship which includes an internal cargo compartment for loading LNG tank containers and equipment for conveying the LNG tank containers to a loading/unloading position in the cargo compartment and loading the LNG tank containers onto an external vehicle in the loading/unloading position and thus can transport the LNG tank containers using existing port facilities without a need to construct separate cargo handling facilities at the port, thereby enabling economical and efficient supply of LNG to an island area or the like, and a method for transporting LNG tank containers by sea using the same. 
     Technical Solution 
     In accordance with one aspect of the present invention, an LNG tank container transport ship includes: an internal cargo compartment for loading LNG tank containers containing LNG; a crane holding the container and moving the container upward or downward to transfer the container to a loading/unloading position in the cargo compartment; at least one primary conveying frame guiding the crane to move in a first direction on a horizontal plane; and at least one secondary conveying frame connected to the primary conveying frame and guiding the crane to move in a second direction on the horizontal plane, intersecting the first direction. 
     The crane may include: a holding unit holding the container; and a vertical drive unit coupled to the holding unit and vertically moving the held container. 
     The primary conveying frame may include a first primary conveying frame formed at one side of the cargo compartment and a second primary conveying frame formed at the other side of the cargo compartment to be spaced apart from and parallel to the first primary conveying frame, and the secondary conveying frame may include a first secondary conveying frame and a second secondary conveying frame spaced parallel to each other between the first primary conveying frame and the second primary conveying frame. 
     The crane may include a vertical drive unit coupled to the first secondary conveying frame and the second secondary conveying frame and vertically driving the crane. In addition, the crane may be moved in the second direction along the first secondary conveying frame and the second secondary conveying frame, and the first secondary conveying frame and the second secondary conveying frame may be moved in the first direction, intersecting the second direction, along the first primary conveying frame and the second primary conveying frame. 
     Each of the first primary conveying frame and the second primary conveying frame may include a protrusion plate inwardly protruding therefrom and a conveying rail formed on an upper surface of the protrusion plate, and each of the first secondary conveying frame and the second secondary conveying frame may include a roller formed at both ends thereof, wherein the roller may be seated on the conveying rail to be movable in the first direction along the first and second primary conveying frames. 
     The vertical drive unit may include a pulley to vertically drive the holding unit. 
     In accordance with another aspect of the present invention, a method for transporting LNG tank containers includes: moving a crane along a primary conveying frame formed in a first direction on a horizontal plane or a secondary conveying frame formed in a second direction intersecting the first direction to transfer the LNG tank containers in a cargo compartment for loading the LNG tank containers containing LNG; holding, by a holding unit of the crane, at least one LNG tank container in the cargo compartment; moving the held LNG tank container to a bed of an external vehicle placed in a loading/unloading position in the cargo compartment; and loading the held LNG tank container onto the bed of the external vehicle to be transported to the outside of a ship by the external vehicle. 
     The primary conveying frame may include a first primary conveying frame formed at one side of the cargo compartment and a second primary conveying frame formed at the other side of the cargo compartment to be spaced apart from and parallel to the first primary conveying frame, and the secondary conveying frame may include a first secondary conveying frame and a second secondary conveying frame spaced parallel to each other between the first primary conveying frame and the second primary conveying frame. 
     The crane may include a vertical drive unit coupled to the first secondary conveying frame and the second secondary conveying frame and vertically driving the crane. The crane may be moved in the second direction on a horizontal plane along the first secondary conveying frame and the second secondary conveying frame, and moved in the first direction on the same horizontal plane, intersecting the second direction, along the first primary conveying frame and the second primary conveying frame. 
     In the method, holding, by the holding unit of the crane, at least one LNG tank container in the cargo compartment may include: moving, by the vertical drive unit, the crane downward to hold the LNG tank container through the holding unit; and lifting up, by the vertical drive unit, the held container. 
     The vertical drive unit may include a pulley to vertically drive the holding unit. 
     The above and other aspects, features, and advantages of the present invention will become apparent from the detailed description of the following embodiments in conjunction with the accompanying drawings. 
     It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Advantageous Effects 
     The present invention provides a ship dedicated to transportation of LNG tank containers which includes a separate internal cargo compartment for loading the LNG tank containers. 
     In addition, the invention provides an LNG tank container transport ship which includes an internal cargo compartment for LNG tank containers and an LNG tank container handling system for loading/unloading the LNG tank containers onto/from an external vehicle in the cargo compartment to allow transportation of LNG tank containers using existing port facilities without a need to construct separate cargo handling facilities at a port or to perform port maintenance, thereby reducing the economic burden of transporting LNG tank containers to an island or the like, while providing ease of loading/unloading to simplify a process of transferring LNG tank containers to the outside of the ship, thereby effectively reducing risk during transportation. 
     Further, the LNG tank containers are loaded onto or unloaded from an external vehicle put into the transport ship, thereby improving transportation reliability and effectively preventing accidents during transportation. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic side view of an LNG tank container transport ship according to one embodiment of the present invention 
         FIG. 2  is a schematic view of an internal cargo compartment system of the LNG tank container transport ship according to the embodiment of the present invention. 
         FIG. 3  is a plan view of the internal cargo compartment system of the LNG tank container transport ship according to the embodiment of the present invention. 
         FIG. 4  is a front view of the internal cargo compartment system of the LNG tank container transport ship according to the present invention. 
         FIGS. 5 to 11  are views sequentially illustrating a transportation method using an LNG tank container transport ship according to one embodiment of the present invention. 
     
    
    
     BEST MODE 
     The above and other aspects, features, and advantages of the present invention will become apparent from the detailed description of the following embodiments in conjunction with the accompanying drawings. It should be noted that like components will be denoted by like reference numerals throughout the specification and the accompanying drawings. In addition, it will be understood that, although the terms “first”, “second”, “one”, “the other”, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. In addition, descriptions of details apparent to those skilled in the art will be omitted for clarity. 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a schematic side view of an LNG tank container T transport ship  1  according to one embodiment of the present invention,  FIG. 2  is a schematic view of an internal cargo compartment S system of the LNG tank container T transport ship  1  according to the embodiment of the present invention,  FIG. 3  is a plan view of the internal cargo compartment S system of the LNG tank container T transport ship  1  according to the embodiment of the present invention, and  FIG. 4  is a front view of the internal cargo compartment S system of the LNG tank container T transport ship  1  according to the present invention. 
     A liquefied natural gas (LNG) tank container T transport ship  1  according to one embodiment of the present invention includes: an internal cargo compartment for loading LNG tank containers containing LNG; a cargo door la coupled to a stem of the ship to open/close the cargo compartment; a crane  10  disposed in the cargo compartment and holding the containers to move the containers upward or downward and transfer the containers to a loading/unloading position in the cargo compartment; at least one primary conveying frame  20  formed at both sides of the top of the cargo compartment and guiding the crane  10  to move in a first direction, which is a direction of the stem of the ship on a horizontal plane; and at least one secondary conveying frame  30  connected to the primary conveying frame  20  and guiding the crane  10  to move in a second direction on the horizontal plane, intersecting the first direction. 
     The transport ship  1  according to this embodiment of the invention includes a separate cargo compartment S to allow the LNG tank containers T to be loaded in the cargo compartment S. That is, the cargo compartment S serves to carry the LNG tank containers T containing LNG. Although the LNG tank container T is described as an example herein, it should be understood that the present invention may be applied to the same or similar types of containers T. 
     Conventionally, in order to efficiently transport containers T loaded in a cargo compartment S of a transport ship  1  to an island or the like, dedicated cargo handling facilities at the dock and port equipment are required. However, this requirement causes problems of cost increase due to port maintenance, construction of the facilities, and the like, and deterioration in transportation reliability. 
     In this embodiment, the separate cargo compartment S is provided to the transport ship  1  and the containers T in the cargo compartment S are directly loaded onto a bed of an external vehicle V, such as a tractor, put into a loading/unloading area of the ship through the opened cargo door la and then transported to the outside, thereby eliminating the need for a complex cargo handling system. Further, using the system of the transport ship  1 , the containers T can be efficiently loaded onto the vehicle or unloaded from the vehicle to be shipped even at a site where a space for installation of related facilities for transporting the containers T is limited, such as an island. 
     The crane  10  may include a vertical drive unit  11  configured to drive the crane in a vertical direction and a holding unit  12  coupled to the vertical drive unit  11  and holding the container. As the holding unit  12 , a container spreader may be used. However, it should be understood that the present invention is not limited thereto and the holding unit may be any suitable device or means for holding containers. 
     The holding unit  12  approaches a target container T through operation of the vertical drive unit  11  and then stably holds the container T. After the holding unit  12  with the container held thereby is moved up by the vertical drive unit  11 , the crane  10  is moved to an external vehicle V having been placed in a desired loading/unloading area to load the container onto the vehicle. The vertical drive unit  11  may include the holding unit  12  holding the container and a movement guide unit connected to the holding unit  12  and guiding vertical movement of the holding unit. Although the vertical drive unit  11  is shown as including a pulley  11  a and a chain-type movement guide unit herein, it should be understood that the present invention is not limited thereto and the vertical drive unit  11  may be configured in various ways. 
     As described above, the transport ship according to this embodiment includes at least one primary conveying frame  20  guiding the crane  10  to move in a first direction on a horizontal plane and at least one secondary conveying frame  30  coupled to the primary conveying frame  20  and guiding the crane to move in a second direction intersecting the first direction on the same horizontal plane. Herein, the first direction and the second direction may refer to any directions intersecting each other on the horizontal plane and may be respectively defined as an x-axis direction and a y-axis direction on a general two-dimensional plane. However, it is obvious to those skilled in the art that the first direction and the second direction may be designed in various ways in view of the movement radius and movement path of the crane  10 . 
     Specifically, as shown in  FIGS. 2 and 3 , the transport ship  1  is provided at the top of the cargo compartment S with a system for moving and loading the containers T onto the external vehicle V. The crane  10  approaches a target container T based on a two-dimensional position of the container in the cargo compartment S, sensed or detected with a camera or the naked eye. Here, the crane  10  is moved to a desired position along the primary conveying frame  20  and secondary conveying frame  30 . As described above, the at least one primary conveying frame  20  may be connected/coupled to the at least one secondary conveying frame  30  to control a wide range of movement of the crane  10  for holding the container in the cargo compartment. Although the structure and arrangement of the primary conveying frame  20  and secondary conveying frame  30  are shown in  FIGS. 2 and 3 , it should be understood that the present invention is not limited thereto. 
     Referring to  FIG. 3 , the crane  10  including the holding unit  12  holding the container T is formed at the top of the cargo compartment S, and the primary conveying frame  20  and the secondary conveying frame  30  are provided to guide the crane  10  to move in the first direction and the second direction on a horizontal plane, respectively. 
     That is, the at least one primary conveying frame  20  serves to guide the crane  10  to move in the first direction on a horizontal plane, and the at least one secondary conveying frame  30  is connected to the primary conveying frame  20  to guide the crane  10  to move in the second direction on the horizontal plane, intersecting the first direction. 
     Specifically, the primary conveying frame  20  may include a first primary conveying frame  21  and a second primary conveying frame  22  respectively formed at right and left ends of the cargo compartment to be spaced parallel to each other. Since both the first primary conveying frame  21  and the second primary conveying frame  22  serve to guide the crane to move in the first direction, the first primary conveying frame  21  and the second primary conveying frame  22  are arranged parallel to each other. 
     Referring to  FIG. 4 , the crane  10  may be coupled to a first secondary conveying frame  31  and a second secondary conveying frame  32 . Specifically, the crane  10  is not fixedly coupled to the first and second secondary conveying frames  31 ,  32 , and is connected to the first and second secondary conveying frames  31 ,  32  to be movable in the second direction, that is, in longitudinal directions of the first and second secondary conveying frames  31 ,  32 . 
     In addition, as shown in  FIG. 3 , the crane  10  connected to the first and second secondary conveying frames is movable in longitudinal directions of the first and second primary conveying frames  21 ,  22  through a movable member  30   a  formed at both ends of each of the first and second secondary conveying frames  31 ,  32 , such that movement of the crane  10  in the first direction can be guided. 
     Here, each of the first and second primary conveying frames  21 ,  22  includes a protrusion plate  20   a  inwardly protruding therefrom and a conveying rail  20   b  formed on the protrusion plate  20   a  to guide movement of the first and second secondary conveying frames  31 ,  32 , such that the movable member  30   a  of each of the first and second secondary conveying frames  31 ,  32  can be moved forward or backward in the first direction along the conveying rail  20   b . The movable member  30   a  may include a roller configured to be seated on the conveying rail  20   b . Although the conveying rail  20   b  and the roller are used to guide movement of the movable member herein, it should be understood that any other suitable component or member may be used to allow the first and second secondary conveying frames  31 ,  32  to be movable forward or backward along the first and second primary conveying frames  21 ,  22 . 
     The crane  10  is moved in the first and second directions on the horizontal plane along the primary conveying frame  20  and the secondary conveying frame  30 , whereby the container held by the crane can be moved to a desired loading/unloading position and then stably placed on the external vehicle V waiting at the loading/unloading position, thereby facilitating transportation of the container. 
     Similarly, the LNG tank container can be transferred to the transport ship by the external vehicle V and then properly loaded in the cargo compartment in the transport ship to be shipped. 
       FIGS. 5 to 11  are views sequentially illustrating a transportation method using an LNG tank container T transport ship  1  according to one embodiment of the present invention. 
     Next, a method of transporting LNG tank containers according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
     The method of transporting LNG tank containers T according to this embodiment includes: opening a cargo door la coupled to a stem of the ship to open/close an internal cargo compartment for loading the LNG tank containers containing LNG; putting an external vehicle into the cargo compartment of the ship through the opened cargo door; moving a crane  10  in a first direction on a horizontal plane, which is a direction of the stem of the ship, or a second direction on the horizontal plane, intersecting the first direction, along a primary conveying frame  20  formed in the first direction at both sides of an upper portion of the cargo compartment and a secondary conveying frame  30  formed in the second direction to hold at least one LNG tank container using a holding unit  12 ; moving the held LNG tank container to a bed of the external vehicle V in the cargo compartment; transporting the LNG tank container loaded onto the external vehicle V to the outside of the ship; and closing the cargo door la. 
     Specifically, first, the cargo door la at the stem of the ship is opened and then the external vehicle V is put into a loading/unloading position in the cargo compartment of the ship through the opened cargo door, as shown in  FIG. 5 . Then, the crane is moved along the primary conveying frame  20  formed in the first direction on the horizontal plane or the secondary conveying frame  30  formed in the second direction, intersecting the first direction, to transfer the LNG tank container within the cargo compartment. Since the first direction and the second direction have already been described in the LNG tank container transport ship according to the present invention, detailed description thereof will be omitted. 
     Then, the crane  10  above the container is moved toward a target container by a vertical drive unit  11  to allow the container to be held by the holding unit  12 , as shown in  FIG. 6 . After the holding unit  12  stably holds the container, and a movement guide unit connected to the holding unit  12  lifts the container. As shown in the drawings, the movement guide unit includes a pulley  11   a  and a chain to move the container upward. Here, the container is preferably lifted up to the top of the cargo compartment to facilitate movement of the crane  10  with the container held thereby. 
     Then, the held LNG tank container is moved to the bed of the external vehicle V in the loading/unloading position in the cargo compartment, as shown in  FIG. 7 . Since the cargo compartment is provided therein with a separate loading/unloading position accommodating the external vehicle V, the external vehicle V can efficiently enter or exit the ship. 
     As shown in  FIGS. 8 and 9 , the crane  10  may be moved to the external vehicle V in the loading/unloading position in the ship along the primary conveying frame and the secondary-conveying frame and put down the container on the bed of the external vehicle V. 
     Conventionally, for external transfer of containers, separate cargo handling equipment, such as a reach stacker, is required or cargo handling facilities need to be provided at the port. However, according to the present invention, transportation of containers T can be easily achieved only with the unloading system of the transport ship  1  without using such separate cargo handling equipment or facilities. 
     Then, as shown in  FIG. 10 , after the container is stably seated on the external vehicle V, the holding unit  12  of the crane  10  is separated from the container and lifted up to an upper end of the crane  10  to be returned to an initial position. 
     Then, as shown in  FIG. 11 , the container is transferred by the external vehicle V, and the crane  10  is moved to a next target container. Then, the external vehicle V exits the ship, and the cargo door la at the stem of the ship is closed, thereby completing the container unloading procedure. 
     Through repetition of this procedure, the containers T can be transported from the cargo compartment S of the ship  1  to demand areas such as an island or the like by the external vehicle V. 
     Similarly, the LNG tank containers can be transported to the transport ship by the external vehicle V and properly loaded in the cargo compartment in the transport ship to be shipped to other areas. 
     Here, the LNG tank container T transportation method as shown in  FIGS. 5 to 11  is performed using the LNG tank container T transport ship  1  as shown in  FIGS. 1 to 4 . Thus, detailed description of corresponding components will be omitted for clarity. 
     Although some embodiments have been described herein, it should be understood that these embodiments are provided for illustration only and are not to be construed in any way as limiting the present invention, and that various modifications, changes, alterations, and equivalent embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention. 
     Therefore, the scope of the present invention should be defined by the appended claims and equivalents thereof. 
     
       
         
           
               
             
               
                   
               
               
                 [List of Reference Numerals] 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 1:  
                 Transport ship 
                 10: 
                 Crane 
               
               
                 11:  
                 Vertical drive unit 
                 11a: 
                 Pulley 
               
               
                 12:  
                 Holding unit 
                 20:  
                 Primary conveying frame 
               
               
                 20a: 
                 Protrusion plate 
                 20b:  
                 Conveying rail 
               
               
                 21:  
                 First primary  
                 22:  
                 Second primary  
               
               
                   
                 conveying frame 
                   
                 conveying frame 
               
               
                 30:  
                 Secondary conveying frame 
                 30a: 
                 Movable member 
               
               
                 31: 
                 First secondary  
                 32: 
                 Second secondary  
               
               
                   
                 conveying frame 
                   
                 conveying frame 
               
               
                 S:  
                 Internal cargo compartment 
                 T:  
                 LNG tank container 
               
               
                 V:  
                 External vehicle 
                 1a:  
                 Cargo door