Patent Publication Number: US-11027459-B2

Title: Fuel tank producing apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from Japanese patent application JP2017-070086 filed on Mar. 31, 2017, the content of which is hereby incorporated by reference into this application. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a fuel tank producing apparatus. 
     Background Art 
     Fuel tanks, such as a hydrogen tank, mounted on fuel-cell and hydrogen vehicles and the like are required to have enough strength to resist a high pressure and to be lightweight. As a method for producing such fuel tanks, there is known a method that includes preparing a tank container by repeatedly winding carbon fibers impregnated with a thermosetting resin such as an epoxy resin around the surface of a cylindrical liner while rotating the cylindrical liner and then thermally curing the thermosetting resin (that is, a filament winding method). 
     Examples of a fuel tank producing apparatus suitable for performing the aforementioned producing method include such an apparatus as the one described in JP 2010-264718 A that includes a rotating portion for rotating a tank container about the central axis thereof, a heat curing furnace for heating the entire tank container, and an air bubble removing portion for removing air bubbles generated on the surface of the tank container due to local heating. According to the fuel tank producing apparatus with such a configuration, removal of air bubbles through blowing of hot air by means of the air bubble removing portion can prevent the dimensions and design of the tank from being affected by the air bubbles. 
     SUMMARY 
     However, in the aforementioned fuel tank producing apparatus, there has been a problem in that it takes time to heat the tank container because the heating on the tank container is performed by the surrounding ambient temperature of the tank container. Further, there has been another problem in that only through local heating with the use of a nozzle, the tank container cannot be uniformly heated. 
     The present disclosure has been made in view of such technical problems, and provides a fuel tank producing apparatus capable of uniformly heating a tank container in a short period of time. 
     The fuel tank producing apparatus according to the present disclosure includes a rotating portion for rotating a tank container about the central axis thereof and a nozzle for blowing gas onto the surface of the tank container, the rotating portion being adapted to rotate the tank container in the reverse direction of a direction in which the gas is blown from the nozzle, the nozzle being located at a position displaced relative to the vertical direction to the central axis of the tank container as viewed from the central axis direction of the tank container. 
     In the fuel tank producing apparatus according to the present disclosure, since the rotating portion is adapted to rotate the tank container in the reverse direction of a direction in which gas is blown from the nozzle, the tank container maintains its contact with the gas blown from the nozzle for a long period of time, so that the thermal efficiency can be improved. In addition, since the nozzle is located at a position displaced relative to the vertical direction to the central axis of the tank container as viewed from the central axis direction of the tank container, the gas blown from the nozzle is allowed to flow in one direction along the tank perimeter, so that the thermal efficiency can be improved. As a result, the tank container can be uniformly heated in a short period of time. 
     Further, in the fuel tank producing apparatus according to the present disclosure, the nozzle extends along the central axis direction of the tank container, and an injection port thereof is preferably seamlessly formed along the central axis direction of the tank container. With such a configuration, the tank container can be uniformly heated. 
     Furthermore, in the fuel tank producing apparatus according to the present disclosure, it is preferable to further include a heating portion for heating a mouthpiece portion provided at an end in the central axis direction of the tank container. With such a configuration, using the thermal conductivity of the mouthpiece portion, the tank container can also be heated from the inside thereof, so that the time needed for the heating can be further reduced. 
     According to the present disclosure, a tank container can be uniformly heated in a short period of time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a fuel tank producing apparatus according to a first embodiment; 
         FIG. 2  is a front schematic view of the internal structure of a heat curing furnace; 
         FIG. 3  is a cross-sectional view of the heat curing furnace taken along line A-A of  FIG. 2 ; 
         FIG. 4  is a schematic cross-sectional view of the structure of a tank container; 
         FIG. 5  is a front schematic view of the heat curing furnace of the fuel tank producing apparatus according to a second embodiment; 
         FIG. 6  is a front schematic view of the heat curing furnace of the fuel tank producing apparatus according to a third embodiment; and 
         FIG. 7  is a schematic cross-sectional view showing a route of heat transmission inside the tank container. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the fuel tank producing apparatus according to the present disclosure will be described below with reference to the drawings. In the illustration of the drawings, the same elements are denoted by the same reference numerals and overlapping descriptions are omitted. 
     First Embodiment 
       FIG. 1  is a perspective view of a fuel tank producing apparatus according to a first embodiment. A fuel tank producing apparatus  1  of the present embodiment is used for producing a fuel tank by heating a tank container  10  that includes a fiber-reinforced resin layer containing a thermosetting resin so as to thermally cure the fiber-reinforced resin layer. The fuel tank producing apparatus  1  is securely supported on a mount  6  and includes a heat curing furnace  2  for heating the tank container  10 , a hot air generator  3  for generating hot air that is disposed outside the heat curing furnace  2 , an intake duct  4  for supplying the heat curing furnace  2  with the hot air generated by the hot air generator  3 , and an exhaust duct  5  for returning an exhaust air from the heat curing furnace  2  to the hot air generator  3 . 
     Herein, the structure of the tank container  10  will be described with reference to  FIG. 2  and  FIG. 4 . The tank container  10  is a hollow container that includes a cylindrical body portion  11  with a substantially uniform radius and convex curved dome portions  12  provided at opposite ends of the body portion  11 . A metal supported shaft  13  is detachably attached to each of the opposite ends (left and right opposite ends in  FIG. 2 ) in the central axis L direction of the tank container  10 . The tank container  10  is driven to rotate about the central axis L thereof by a rotating motor  211  while being rotatably supported, via the supported shafts  13 , by bearing members  210  of a rotating portion  21  that will be described later. 
     The tank container  10  includes a liner  10   a  that has a storage space for storing fuel therein, a fiber-reinforced resin layer  10   b  tightly attached to the outer wall of the liner  10   a , a valve-side mouthpiece portion  10   c , and an end-side mouthpiece portion  10   d . The liner  10   a  is made of a resin material or a light metal material, such as aluminum. The fiber-reinforced resin layer  10   b  is a reinforcing layer that covers the outer surface of the liner  10   a , and is made of reinforcing fibers of a carbon fiber reinforced plastic (CFRP) and the like, to be wound around the outer surface of the liner  10   a , and a thermosetting resin for binding the reinforcing fibers together. 
     The left and right opposite ends in the central axis L direction of the liner  10   a  and fiber-reinforced resin layer  10   b  are open, and the valve-side mouthpiece portion  10   c  and the end-side mouthpiece portion  10   d  are inserted into one (left side in  FIG. 2 ) and the other (right side in  FIG. 2 ) of the ends, respectively. Further, the valve-side mouthpiece portion  10   c  and the end-side mouthpiece portion  10   d  are each detachably coupled to each of the aforementioned supported shafts  13 . The valve-side mouthpiece portion  10   c  and the end-side mouthpiece portion  10   d  are each made of, for example, a thermally conductive metal member, such as stainless steel and aluminum, or a resin material with a high strength. 
       FIG. 2  is a front schematic view of the internal structure of the heat curing furnace.  FIG. 3  is a cross-sectional view of the heat curing furnace taken along line A-A of  FIG. 2 . In  FIG. 2 , for easy understanding of the internal structure, the front side of an furnace wall  24  is omitted. 
     The heat curing furnace  2  has a space for accommodating the tank container  10  therein and is generally substantially in a box shape. The heat curing furnace  2  is formed such that the furnace wall  24  with heat resistance and a heat retaining property is attached to, for example, a metal frame body so as to surround it from the four sides. The furnace wall  24  is provided with a through hole  23  passing therethrough on each of the left and right sides of the heat curing furnace  2 . Further, tip ends of the supported shafts  13  attached to the left and right ends of the tank container  10  are each inserted through the through hole  23  and also securely inserted into the bearing member  210  of the rotating portion  21 . 
     The heat curing furnace  2  is externally provided with the rotating portion  21  for rotating the tank container  10  about the central axis thereof. The rotating portion  21  includes a pair of bearing members  210  that are fixed to the outside of the furnace wall  24  of the heat curing furnace  2  and that support the aforementioned supported shafts  13 , and the rotating motor  211  provided to one side of the pair of bearing members  210 . With the rotating portion  21  externally provided to the heat curing furnace  2  in such a manner, the internal space of the heat curing furnace  2  can be reduced, so that the overall size of the heat curing furnace  2  can be reduced. In addition, as compared to a heat curing furnace with a rotating portion internally provided, no heat is absorbed by the rotating portion. Therefore, energy saving can also be achieved. 
     A heat intake and exhaust box  26  is attached to the ceiling of the heat curing furnace  2 . The heat intake and exhaust box  26  is internally provided with an intake passage  261  that allows the intake duct  4  to communicate with a hot air blowing portion  22  that will be described later and an exhaust passage  262  that allows the exhaust duct  5  to communicate with the inside of the heat curing furnace  2  (see  FIG. 3 ). 
     The hot air blowing portion  22  for blowing hot air onto the surface of the tank container  10  is hung below the heat intake and exhaust box  26 . The hot air blowing portion  22  has a flat box shaped hot air rectifying chamber  220  that extends along the central axis L direction of the tank container  10 , two connecting tubes  221  provided above the hot air rectifying chamber  220  and connecting the hot air rectifying chamber  220  and the heat intake and exhaust box  26 , and an integrally-formed nozzle  222  provided below the hot air rectifying chamber  220  to blow hot air onto the surface of the tank container  10 . 
     The two connecting tubes  221  are disposed at the same intervals from each other along the longitudinal direction (that is, the central axis L direction of the tank container  10 ) of the hot air rectifying chamber  220 . Meanwhile, the integrally-formed nozzle  222  in a slit form extends along the central axis L direction of the tank container  10 . The integrally-formed nozzle  222 , for example, extends from one end to the other of the body portion  11  and has a structure with a unit injection port as a whole instead of a plurality of separate nozzles connected. Further, the injection port of the nozzle  222  is seamlessly formed along the longitudinal direction (that is, the central axis L direction of the tank container  10 ) of the body portion  11  of the tank container  10 , and blows hot air onto the surface of the body portion  11 . With the use of the integrally-formed nozzle  222  as described above, the surface of the body portion  11  can be evenly and uniformly heated. It should be noted that the number of the connecting tubes  221  is not limited to that in the aforementioned description and drawings, but may be changed as appropriate. Further, the nozzle  222  may be provided such that, for example, a plurality of separate nozzles are linearly disposed at the same intervals from each other. 
     In the present embodiment, the nozzle  222  is located at a position displaced relative to the vertical direction to the central axis L of the tank container  10  as viewed from the central axis L direction of the tank container  10 . Specifically, as shown in  FIG. 3 , the nozzle  222  is located at a position displaced to the left relative to the vertical direction to the central axis L of the tank container  10 . In other words, the nozzle  222  is eccentrically positioned to the left side relative to the center of the tank container  10  in the horizontal direction. 
     Further, in the present embodiment, the rotating portion  21  is configured to rotate the tank container  10  in the reverse direction of the direction in which hot air is blown from the nozzle  222 . Specifically, as shown in  FIG. 3 , since the nozzle  222  is located at a position displaced to the left side relative to the vertical direction to the central axis L of the tank container  10 , the hot air blown from the nozzle  222  flows counterclockwise (see an arrow F 1 ) along the surface of the tank container  10 . Meanwhile, the tank container  10  is rotated clockwise (see an outline arrow F 2 ) by the rotating portion  21 . 
     In the fuel tank producing apparatus  1  with the aforementioned configuration, since hot air is blown from the nozzle  222  directly onto the surface of the tank container  10  so as to heat the fiber-reinforced resin layer of the tank container  10 , the tank container  10  can be heated in a short period of time. Further, since the rotating portion  21  is configured to rotate the tank container  10  in the reverse direction of the direction in which the hot air is blown from the nozzle  222 , the hot air blown from the nozzle  222  is dispersed around the tank container  10  so that the tank container  10  maintains its contact with the hot air for a long period of time, thereby improving the thermal efficiency. 
     Moreover, with the nozzle  222  located at a position displaced to the left side relative to the vertical direction to the central axis L of the tank container  10  as viewed from the central axis L direction of the tank container  10 , the hot air blown from the nozzle  222  is allowed to flow in one direction counterclockwise along the tank perimeter, so that the thermal efficiency can be further improved. As a result, the tank container  10  can be uniformly heated in a short period of time and a stable quality in rigidity of the tank container  10  can be obtained. 
     Further, as compared to conventional fuel tank producing apparatuses that perform heating by the surrounding ambient temperature of the tank container, with such improved thermal efficiency, a high-capacity hot air circulator and rectifying space can be omitted, so that the compact apparatus as a whole can be achieved and the cost can be reduced. Furthermore, through direct heating of the tank container  10  by means of the nozzle  222 , the surrounding space of the tank container  10  can be saved, and thus the inside of the heat curing furnace  2  can be downsized. 
     In addition, according to the heat curing furnace  2  with the aforementioned configuration, a rapid increase in temperature can be addressed, and therefore, in accordance with the resin viscosity that depends on the curing reaction state of the thermosetting resin, such as an epoxy resin with which carbon fibers are impregnated, for example, the temperature profile is minutely set while the speed of rotating the tank container  10  is changed so as to perform temperature control, so that reduction in the time of performing thermal curing and quality in rigidity can be both realized. 
     Second Embodiment 
       FIG. 5  is a front schematic view of the heat curing furnace of the fuel tank producing apparatus according to a second embodiment. The structure of a heat curing furnace  2 A of the present embodiment is the same as that of the aforementioned first embodiment, except that the heat curing furnace  2 A is further provided with a hot air blowing portion  29  for the dome portion that blows hot air onto the dome portion  12  of the tank container  10 . Herein, only such a difference therebetween will be described. 
     As shown in  FIG. 5 , the left and right opposite sides of the hot air blowing portion  22 , which corresponds to the body portion  11  of the tank container  10 , are provided with the hot air blowing portions  29  for the dome portions that correspond to the left and right dome portions  12  of the tank container  10 . Each of the hot air blowing portions  29  for the dome portions is hung below the heat intake and exhaust box  26  and includes a connecting tube  291  connected to the intake passage  261  of the heat intake and exhaust box  26 , a hot air rectifying chamber  290  for rectifying the hot air supplied via the connecting tube  291 , and an integrally-formed nozzle  292  that blows the hot air rectified in the hot air rectifying chamber  290  onto the dome portion  12 . 
     The hot air blowing portion  29  for the dome portion is disposed so as to follow the shape of the dome portion  12 . More specifically, the integrally-formed nozzle  292  is disposed such that the height from the dome portion  12  and blowing angle thereof are changed so as to follow the convex curved shape of the dome portion  12 , so that the hot air is orthogonally blown onto the convex curved surface of the dome portion  12 . An injection port of the nozzle  292  is seamlessly formed while it curves along the convex curved shape of the dome portion  12 . With the use of the integrally-formed nozzle  292  in this manner, the surface of the dome portion  12  can be evenly and uniformly heated. Further, the hot air rectifying chamber  290  of the hot air blowing portion  29  for the dome portion is formed such that it curves along the convex curved shape of the dome portion  12 . 
     Herein, the temperature or blowing speed of the hot air blown from the nozzle  292  of the hot air blowing portion  29  for the dome portion may be set to be either the same as or different from the temperature or blowing speed of the hot air blown from the nozzle  222  that corresponds to the body portion  11 . As shown in  FIG. 4 , when the fiber-reinforced resin layer  10   b  of the dome portion  12  is thicker than that of the body portion  11 , with the temperature or blowing speed of the hot air blown from the nozzle  292  set higher than the temperature or blowing speed of the hot air blown from the nozzle  222 , for example, variation in the thermal curing time due to the difference in thickness is reduced, thereby more easily reducing the time of entirely heating the tank container  10 . 
     With the fuel tank producing apparatus  1 A with the aforementioned configuration, the same function and effects as those of the aforementioned first embodiment can be obtained. In addition, since the fuel tank producing apparatus  1 A further includes the hot air blowing portions  29  for the dome portions that correspond to the left and right dome portions  12  of the tank container  10 , the hot air can also be directly blown onto the surfaces of the dome portions  12  so as to heat them (see arrows F 3  in  FIG. 5 ). Through directly heating the dome portions  12  as well as the body portion  11  of the tank container  10  in the aforementioned manner, the tank container  10  can be uniformly heated and the heating time can be further reduced. 
     Third Embodiment 
       FIG. 6  is a front schematic view of the heat curing furnace of the fuel tank producing apparatus according to a third embodiment. The structure of a heat curing furnace  2 B of the present embodiment is the same as that of the aforementioned first embodiment, except that the heat curing furnace  2 B is further provided with a mouthpiece heating portion  28  to heat the mouthpiece portion of the tank container  10 . Herein, only such a difference therebetween will be described. 
     As shown in  FIG. 6 , the left and right opposite sides of the hot air blowing portion  22  are provided with the mouthpiece heating portions  28  to heat the valve-side mouthpiece portion  10   c  or end-side mouthpiece portion  10   d  of the tank container  10  via the supported shafts  13 . Each of the mouthpiece heating portions  28  is hung below the heat intake and exhaust box  26  and has a connecting tube  281  connected to the intake passage  261  of the heat intake and exhaust box  26 , a hot air rectifying chamber  280  for rectifying the hot air supplied via the connecting tube  281 , and a nozzle  282  for blowing the hot air rectified in the hot air rectifying chamber  280  onto the supported shaft  13 . 
     In  FIG. 6 , the mouthpiece heating portion  28  disposed on the left side of the hot air blowing portion  22  (hereinafter referred to as a left-side mouthpiece heating portion  28 ) is positioned vertically above the supported shaft  13  attached to the left end of the tank container  10 , and heats the valve-side mouthpiece portion  10   c  via the supported shaft  13 . It should be noted that in the present embodiment, the supported shaft  13  is made of a thermally conductive metal member such as stainless steel, and the valve-side mouthpiece portion  10   c  and end-side mouthpiece portion  10   d  are both made of aluminum. 
     Further, as indicated by an arrow F 4  in  FIG. 6  and  FIG. 7 , some of the heat from the left-side mouthpiece heating portion  28  is transmitted to the fiber-reinforced resin layer  10   b  on the dome portion  12  side via the supported shaft  13  and valve-side mouthpiece portion  10   c , and some to the fiber-reinforced resin layer  10   b  on the body portion  11  side via the supported shaft  13 , valve-side mouthpiece portion  10   c , and liner  10   a.    
     Meanwhile, in  FIG. 6 , the mouthpiece heating portion  28  disposed on the right side of the hot air blowing portion  22  (hereinafter referred to as a right-side mouthpiece heating portion  28 ) is positioned vertically above the supported shaft  13  attached to the right end of the tank container  10 , and heats the end-side mouthpiece portion  10   d  via the supported shaft  13 . As indicated by the arrow F 4  in  FIG. 6  and  FIG. 7 , some of the heat from the right-side mouthpiece heating portion  28  is transmitted to the fiber-reinforced resin layer  10   b  on the dome portion  12  side via the supported shaft  13  and end-side mouthpiece portion  10   d , and some to the fiber-reinforced resin layer  10   b  on the body portion  11  side via the supported shaft  13 , end-side mouthpiece portion  10   d , and liner  10   a.    
     Herein, the temperature or blowing speed of the hot air blown from the nozzle  282  of the mouthpiece heating portion  28  may be set to be either the same as or different from the temperature or blowing speed of the hot air blown from the nozzle  222  of the hot air blowing portion  22 . As shown in  FIG. 4  and  FIG. 7 , when the fiber-reinforced resin layer  10   b  of the dome portion  12  is thicker than that of the body portion  11 , with the temperature or blowing speed of the hot air blown from the nozzle  282  set higher than the temperature or blowing speed of the hot air blown from the nozzle  222 , for example, variation in the thermal curing time due to the difference in thickness is reduced, thereby more easily reducing the time of entirely heating the tank container  10 . 
     With the fuel tank producing apparatus  1 B with the aforementioned configuration, the same function and effects as those of the aforementioned first embodiment can be obtained. In addition, since the fuel tank producing apparatus  1 B further includes the mouthpiece heating portion  28  to heat the mouthpiece portion of the tank container  10 , the tank container  10  can also be heated from the inside thereof via the supported shafts  13  and the valve-side mouthpiece portion  10   c  or the end-side mouthpiece portion  10   d . As a result, the time required for heating the tank container  10  can be further reduced. 
     It should be noted that the mouthpiece heating portion is not limited to the aforementioned one including a nozzle, but may be any heating portion that performs infrared or induction heating or that uses a non-contact heat source, as appropriate. 
     Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited thereto, and any design changes are possible without departing from the spirit and scope of the present disclosure described in the claims. For example, in the aforementioned embodiments, the heat curing furnace  2  externally provided with the rotating portion  21  for rotating the tank container  10  has been described as an example, but the rotating portion  21  may be disposed inside the heat curing furnace  2 , as appropriate. 
     Further, in the aforementioned embodiments, the description has been made of an example of the apparatus with the nozzle  222  located at a position displaced to the left side relative to the vertical direction to the central axis L of the tank container  10  as viewed from the central axis L direction of the tank container  10 , but the nozzle  222  may be displaced to the right side relative to the vertical direction to the central axis L of the tank container  10 . In this case, the hot air blown from the nozzle  222  flows clockwise along the perimeter of the tank container  10 , and the rotating portion  21  is thus configured to rotate the tank container  10  counterclockwise. 
     DESCRIPTION OF SYMBOLS 
     
         
           1 ,  1 A,  1 B Fuel tank producing apparatus 
           2 ,  2 A,  2 B Heat curing furnace 
           3  Hot air generator 
           4  Intake duct 
           5  Exhaust duct 
           10  Tank container 
           10   a  Liner 
           10   b  Fiber-reinforced resin layer 
           10   c  Valve-side mouthpiece portion 
           10   d  End-side mouthpiece portion 
           11  Body portion 
           12  Dome portion 
           13  Supported shaft 
           21  Rotating portion 
           22  Hot air blowing portion 
           23  Through hole 
           24  Furnace wall 
           26  Heat intake and exhaust box 
           28  Mouthpiece heating portion 
           29  Hot air blowing portion for dome portion 
           210  Bearing member 
           211  Rotating motor 
           220 ,  280 ,  290  Hot air rectifying chamber 
           221 ,  281 ,  291  Connecting tube 
           222 ,  282 ,  292  Nozzle 
         L Central axis