Patent Number: 
Section: claims

1. A steam generator, comprising:a heat transfer tube assembly having a plurality of spiral heat transfer tubes arranged on a concentric circle; anda header formed to connect the heat transfer tube assembly and a nozzle,wherein one end of each of the plurality of spiral heat transfer tubes is extended in a vertical direction to form one end of the heat transfer tube assembly, andthe header is disposed on an upper or lower side of the heat transfer tube assembly to be connected to one end of the heat transfer tube assembly along a vertical direction, andthe header is connected along a horizontal direction to the nozzle disposed at one side of the header, andthe header has an L-shape to switch the flow direction of fluid flowing in a vertical direction through one end of the heat transfer tube assembly to a horizontal direction so as to flow to the nozzle,wherein the header comprises:a tube plate member coupled to one end of the heat transfer tube assembly;a cover member fixed to an opposite side to a side to which one end of the heat transfer tube assembly is coupled in the tube plate member, and connected to an edge of the tube plate member to form a fluid flow space between the tube plate member and the cover member; anda nozzle connection member coupled to a side portion of the tube plate member and a side portion of the cover member to communicate with the flow space formed by the tube plate member and the cover member, and connected to the nozzle. 2. The steam generator of claim 1, wherein one end of the heat transfer tube assembly is inserted into the header along a vertical direction and connected to the header. 3. The steam generator of claim 1, wherein the tube plate member comprises:a tube portion formed in a cylindrical shape to surround one end of the heat transfer tube assembly;a plate portion having a plurality of insertion holes formed to block an upper portion of the tube portion, and formed to be forcibly inserted and coupled to one end of each of the plurality of spiral heat transfer tubes; anda flange portion protruded upward from an edge of the plate portion and coupled to the cover member to form the flow space above the plate portion. 4. The steam generator of claim 3, wherein at least one of the tube plate member, the cover member, and the nozzle connection member has a fitting protrusion protruded from one surface thereof, anda counterpart coupled to at least one of the tube plate member, the cover member, and the nozzle connection member has a fitting groove portion formed to accommodate the fitting protrusion, andthe fitting protrusion is inserted into the fitting groove portion to fix a relative position between the at least one and the counterpart. 5. The steam generator of claim 3, wherein the cover member is fixed to an upper end of the flange portion, andone side of the cover member and one side of the flange portion are open to form a fluid access port for allowing the flow space to communicate with an inner space of the nozzle connection member. 6. The steam generator of claim 3, wherein the plurality of insertion holes are formed at positions spaced apart from each other along a plurality of concentric circles around the center of the tube portion. 7. The steam generator of claim 6, wherein a plurality of spiral heat transfer tubes being forcibly inserted and coupled to a plurality of insertion holes formed along any one of the plurality of concentric circles are formed in the same shape as each other. 8. The steam generator of claim 1, wherein the nozzle connection member is welded and coupled to a circumference of a fluid access port formed by coupling between the tube plate member and the cover member, andthe nozzle connection member comprises:a first portion coupled to a circumference of the access port; anda second portion connected to the nozzle, anda diameter of the first portion is greater than that of the second portion. 9. The steam generator of claim 1, wherein:one side of the tube plate member and one side of the cover member form the nozzle connection portion connected to the nozzle. 10. The steam generator of claim 9, wherein the tube plate member comprises:a tube portion formed in a cylindrical shape to surround one end of the heat transfer tube assembly;a plate portion having a plurality of insertion holes formed to block an upper portion of the tube portion, and formed to be forcibly inserted and coupled to one end of each of the plurality of spiral heat transfer tubes;a flange portion protruded upward from an edge of the plate portion and coupled to the cover member to form the flow space above the plate portion; anda first extension portion protruded from one side of the plate portion and one side of the flange portion to form a lower portion of the nozzle connection portion. 11. The steam generator of claim 10, wherein the cover member comprises:a dome portion fixed to an upper end of the flange portion to form the flow space; anda second extension portion protruded from one side of the dome portion to form an upper portion of the nozzle connection portion, andthe first extension portion and the second extension portion are coupled to each other to form an inner space communicating with the flow space. 12. The steam generator of claim 1, wherein the header comprises:the tube plate member having an open upper portion; andthe cover member formed to cover the open upper portion of the tube plate member, andone end of each of the plurality of spiral heat transfer tubes is inserted and coupled to a lower portion of the tube plate member, andthe fluid flow space is formed inside the tube plate member, andone side of the tube plate member is connected to the nozzle. 13. The steam generator of claim 12, wherein the tube plate member comprises:a tube portion formed in a cylindrical shape to surround one end of the heat transfer tube assembly;a plate portion having a plurality of insertion holes formed to block an upper portion of the tube portion, and formed to be forcibly inserted and coupled to one end of each of the plurality of spiral heat transfer tubes;a flange portion protruded in a dome shape from an edge of the plate portion to form the flow space above the plate portion, and form an opening portion at an upper portion thereof; andthe nozzle connection portion protruded in a pipe shape from one side of the plate portion and one side of the flange portion and connected to the nozzle.