Abstract:
Hot gas torches include a nozzle that includes an internal conduit that extends between an inlet end and an outlet end and a heating unit disposed external the internal conduit, wherein the heating unit heats the internal conduit such that a gas that enters the internal conduit at the inlet end is heated before it exits the internal conduit at the outlet end.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The subject matter disclosed herein relates to heating materials and, more specifically, to heating materials using a hot gas torch. 
         [0002]    Materials are often heated to adjust their performance for a given application. For example, metals and alloys can be heated (e.g., heat treated, annealed, tempered, etc.) to adjust their microstructure so that they become harder, softer, more durable or achieve a variety of other properties specific to that material. Likewise, weld material, braze material and the like can be heated until they become molten so that they can subsequently cool and bond with a substrate component. Such materials can be used to repair cracks, join multiple parts, build up voids in the material or otherwise add new material to a substrate. Non-metals such as ceramic, polymeric, organic or composite materials may also be heated in a variety of applications. 
         [0003]    One way to apply heat to a material is through the use of a flame. Blow torches, for example, can burn combustible fuel (e.g., oxyacetylene, acetylene, propane, etc.) proximate to a material to increase its temperature. However, some materials such as various metals and alloys can become oxidized on their surfaces as a result of the combusting fuel. The oxidization can potentially decrease physical or visual performance and/or require subsequent processing to remove oxidized portion. Other materials may degrade combust or otherwise deteriorate when a flame is present. Other heating methods such as arc welding may not be suitable for certain components (e.g., parts with nearby electrical circuits) due to potential arcing to neighboring areas that would damage part of the component. Even other processes may require any heating to occur in an inert atmosphere to limit any contamination of the heating site; however, it may be difficult to contain an entire component in an inert atmosphere due to the component&#39;s overall size or shape. 
         [0004]    Accordingly, alternative hot gas torches, hot gas torch systems and methods for using the same would be welcome in the art. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    In one embodiment, a hot gas torch is provided. The hot gas torch includes a nozzle that includes an internal conduit that extends between an inlet end and an outlet end. The hot gas torch further includes a heating unit disposed external the internal conduit, wherein the heating unit heats the internal conduit such that a gas that enters the internal conduit at the inlet end is heated before it exits the internal conduit at the outlet end. 
         [0006]    In another embodiment, a hot gas torch system is provided. The hot gas torch system includes a nozzle that includes an internal conduit that extends between an inlet end and an outlet end and a heating unit disposed external the internal conduit that heats the internal conduit. The hot gas torch system further includes a gas supply connected to the inlet end of the internal conduit such that a gas that enters the inlet end of the internal conduit from the gas supply becomes heated before it exits the outlet end of the internal conduit. 
         [0007]    In yet another embodiment, a hot gas heating method is provided. The hot gas heating method includes heating an internal conduit of a nozzle using a heating unit, wherein the internal conduit extends from an inlet end to an outlet end, and wherein the heating unit is disposed external the internal conduit, and passing a gas through the internal conduit such that the gas is heated without combusting as it travels from the inlet end to the outlet end. The hot gas heating method further includes heating a target site of a substrate using the gas that exits the outlet end of the internal conduit. 
         [0008]    These and additional features provided by the embodiments discussed herein will be more fully understood in view of the following detailed description, in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the inventions defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which: 
           [0010]      FIG. 1  is an exemplary hot gas torch according to one or more embodiments shown or described herein; 
           [0011]      FIG. 2  is an exemplary nozzle for a hot gas torch according to one or more embodiments shown or described herein; 
           [0012]      FIG. 3  is another exemplary nozzle for a hot gas torch according to one or more embodiments shown or described herein; 
           [0013]      FIG. 4  is an exemplary hot gas torch system according to one or more embodiments shown or described herein; and 
           [0014]      FIG. 4  is an exemplary hot gas heating method according to one or more embodiments shown or described herein. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
         [0016]    When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
         [0017]    Hot gas torch systems disclosed herein generally comprise a hot gas torch connected to a gas supply. The hot gas torch comprises a nozzle that has an internal conduit for a gas, such as an inert gas, to pass there through. The hot gas torch further comprises a heating unit, such as an induction coil, that heats the internal conduit to an elevated temperature. By heating the internal conduit using the heating unit, gas can become heated as it passes through the nozzle&#39;s internal conduit so that it exits at an elevated temperature without the use of combustion. The exiting hot gas may then be directed to heat a variety of different materials for numerous applications. 
         [0018]    Referring now to  FIG. 1 , a hot gas torch  10  is illustrated. As discussed above, the hot gas torch  10  comprises a nozzle  20  and a heating unit  30 . The nozzle  20  comprises an internal conduit  25  surrounded by a wall  26 . The internal conduit  25  extends from an inlet end  21  of the nozzle  20  all the way to an outlet end  22  of the nozzle  20 . 
         [0019]    The nozzle  20  may comprise any size and shape that allows for the internal conduit  25  to pass there through as will become appreciated herein. For example, in some embodiments, such as that illustrated in  FIG. 1 , the nozzle  20  may comprise an extended cylinder and the internal conduit  25  may comprise a linear tube passing directly through the nozzle  20 . In some embodiments, such as that illustrated in  FIG. 2 , the nozzle  20  may comprise a non-linear configuration such as a serpentine configuration and the internal conduit  25  may comprise an open tube passing directly through the nozzle  20 . Such a configuration may allow for a longer internal conduit  25  for the gas to pass through thereby increasing the dwell time of the gas in the internal conduit  25 . In even other embodiments, the nozzle  20  may comprise any other linear or non-linear configuration such as straight, curved, spiraled, switchbacked, or any other geometric or non-geometric configuration or combinations thereof. 
         [0020]    Moreover, the internal conduit  25  may also comprise any size and shape within the nozzle  20 . For example, in some embodiments, such as that illustrated in  FIGS. 1 and 2 , the internal conduit  25  may comprise a direct passageway that is centered within the nozzle  20  for the entire length of the nozzle  20 . However, in some embodiments, the internal conduit  25  may alternatively or additionally take on other configurations throughout the nozzle  20  besides a direct passageway through its center. For example, as illustrated in  FIG. 3 , the internal conduit  25  itself may comprise a non-linear path such as serpentine configuration through the nozzle  20 . Such a configuration may allow for a longer internal conduit  25  for the gas to pass through while still using a nozzle  20  with a relatively basic external shape (e.g., cylinder, cube, etc.). In even some embodiments, the internal conduit  25  may comprise any other linear or non-linear configuration such as straight, curved, spiraled, switchbacked, or any other geometric or non-geometric configuration or combinations thereof. The internal conduit  25  and the nozzle  20  may therefore comprise a variety of combinations of size, shapes and configurations to manipulate the dwell time of the gas  55  in the internal conduit  25  (and thus the amount of heat applied to the gas  55  as will become appreciated herein). 
         [0021]    Furthermore, the internal conduit  25  may comprise a variety of configurations to manipulate the gas  55  as it exits the outlet end  22 . For example, in some embodiments the internal conduit  25  may comprise a tapered configuration for either converging or diverging the gas  55  as it exits. In some embodiments the internal conduit  25  may comprise a plurality of gas outlets (such as in a showerhead configuration) so that the gas  55  exits in a plurality of locations. 
         [0022]    Referring to  FIGS. 1-3 , the nozzle  20  can comprise a variety of wall  26  configurations that allow for an external energy (e.g., heat) to be transferred from the heating unit  30  to the internal conduit  25  of the nozzle  20 . For example, the nozzle  20  can comprise a single wall  26  that comprises an outer surface  28  and an inner surface  29  such that the inner surface  29  defines the internal conduit  25  (as illustrated in  FIGS. 1-3 ). Alternatively or additionally, in some embodiments, the nozzle  20  may comprise a plurality of walls  26  that combine to make up the outer surface  28  and the inner surface  29  of the nozzle  20 . For example, in some embodiments, the nozzle  20  may comprise an inner wall that makes up the inner surface  29  of the nozzle  20  and an outer wall that surrounds the inner wall and makes up the outer surface  28  of the nozzle  20 . In such embodiments, the inner wall and the outer wall may be touching or may be separated from one another (such as by a gap of air). The nozzle  20  may comprise a single wall  26  for its entire length, multiple walls  26  for its entire length or combinations of a single wall  26  and multiple walls  26 . 
         [0023]    Moreover, in some embodiments, the wall  26  of the nozzle  20  can comprise one or more materials that can be externally heated (i.e., on the outer surface  28  of the nozzle  20 ) and at least partially transfer some of that heat (or other energy) to the inner surface  29  (and thus the internal conduit  25 ) of the nozzle  20 . For example, in some embodiments, the wall  26  can comprise graphite. In some embodiments, the wall  26  can comprise tungsten. In some embodiments, the wall can comprise different materials or different combinations of materials at different locations. While specific materials have been presented herein, it should be appreciated that these are exemplary only and other materials that allow for the passage of energy (e.g., heat) to the internal conduit may additionally or alternatively be incorporated. 
         [0024]    Referring still to  FIGS. 1-3 , the hot gas torch  10  further comprises a heating unit  30 . The heating unit  30  provides energy (e.g., heat) to the nozzle  20  so that the internal conduit  25  becomes heated. The heating unit  30  can comprise a variety of different types of heating systems that can heat the internal conduit  25 . For example, in some embodiments, such as that illustrated in  FIGS. 1-3 , the heating unit  30  can comprise an induction heating unit. In such embodiments the heating unit  30  can comprise an induction coil  32  connected to a power supply  34  by an electrical connection  36 . The induction coil  32  can then be positioned proximate the nozzle  20  in a variety of configurations. For example, where the nozzle  20  comprises a straight cylinder, the induction coil  32  can be wrapped around the exterior of the nozzle  20  (as illustrated in  FIGS. 1 and 4 ). Alternatively or additionally, where the nozzle  20  comprises a straight cylinder, the induction coil  32  may not surround the entire circumference of the nozzle  20 , but be placed along to just one side of the nozzle  20 . Where the nozzle  20  comprises a different non-linear configuration, such as the serpentine configuration illustrated in  FIG. 2 , the induction coil  32  may be wrapped around the outer perimeter of the entire nozzle  20 , or may be wrapped around the length of the nozzle  20  such that the induction coil  32  also follows the serpentine pattern. 
         [0025]    In some embodiments, the heating unit  30  can comprise any other device or system that can heat the internal conduit  25 . For example, in some embodiments the heating unit  30  can comprise a resistance heating unit. In such embodiments the heating unit  30  can connect to at least part of the nozzle  20  and pass a current there through such that the internal conduit  25  is heated. In other embodiments, the heating unit  30  can comprise a combustible heat source such as a blowtorch. In such embodiments the heat may be applied external the nozzle  20  and transferred from the outer surface  28  to the inner surface  29  in order to heat the internal conduit  25 . While specific heating sources have been disclosed herein, it should be appreciated that these are exemplary only and any other heating source may additionally or alternatively be employed to heat the internal conduit  25  and any gas  55  that passes there through. 
         [0026]    Referring now to  FIGS. 1 and 4 , the heating unit  30  may be disposed in a variety of locations external the internal conduit  25 . For example, in some embodiments the heating unit  30  can be disposed external the nozzle  20 . Such embodiments may be realized when the heating unit  30  comprises an induction coil  32  that is wrapped around the outer surface  28  of the nozzle  20 . The induction coil  32  may then radiate heat through the wall  26  to heat the internal conduit  25  such that gas  55  passing through the internal conduit  25  becomes heated. In some embodiments, the heating unit  30  may be integrated with the nozzle  20 . Such embodiments may be realized, for example, when the heating unit  30  comprises a resistance heating such that a current is applied directly to the wall  26  of the nozzle. The heating unit  30  may further be disposed across the entire length of the nozzle  20  or across one or more portions of the length of the nozzle  20 . Furthermore, the hot gas torch  10  can comprise a single heating unit  30  or a plurality or heating units  30 . 
         [0027]    Referring now to  FIG. 4 , the hot gas torch system  1  comprises a gas supply  50  connected to the hot gas torch  10  via a connection  60 . The gas supply  50  provides gas  55  to the internal conduit  25  of the nozzle  20 . For example, in some embodiments the gas supply  50  can comprise a gas tank  51  and a gas line  52 . The gas line  52  can extend from the gas tank  51  to the internal conduit  25  of the hot gas torch  10  and be connected thereto by a connection  60 . The connection  60  can comprise any type of connection that allows the gas  55  to flow from the gas line  52  to the internal conduit  25  with no or minimal leakage. For example, the connection  60  can comprise a flange, hose and/or fitting that connects the gas line  52  to the internal conduit  25 . Moreover, the gas  55  can comprise any type of gas that can be heated and applied to a target site  71  of a substrate  70 . For example, in some embodiments the gas  55  can comprise an inert gas such as nitrogen. In some embodiments the gas  55  may comprise a mixture of different gases. 
         [0028]    The gas  55  may thus travel through the internal conduit  25  and become heated prior to exiting the nozzle  20  at the outlet end  22 . The temperature of the gas  55  will depend at least in part on the temperature the internal conduit  25  is heated to and the dwell time of the gas  55  in the internal conduit. Thus, to produce a hotter gas, the internal conduit  25  may be heated to a higher temperature, the length of the internal conduit  25  may be increased and/or the flow rate of the gas  55  may be decreased (such as by decreasing the pressure). 
         [0029]    Still referring to  FIG. 4 , the hot gas torch system  1  can comprise a variety of additional equipment to assist in the application of heated gas  55  to the target site  71  of the substrate  70 . For example, in some embodiments the hot gas torch system  1  can comprise one or more temperature sensors  40  (e.g., thermocouples, thermometers, pyrometers, etc.) disposed at one or more locations around the hot gas torch  10 . The one or more temperature sensors  40  can measure the temperature of the gas  55  proximate the outlet end  22  (e.g., as it passes through and/or exits the internal conduit  25 ) so that the temperature of the gas  55  applied to the substrate  70  can be monitored. In some embodiments, the one or more temperature sensors  40  may send temperature feedback to a controller  45  that controls the heating unit  30 . In such embodiments the controller  45  can adjust the amount of energy (e.g., heat) applied to the internal conduit  25  so that the temperature of the gas  55  leaving the outlet end  22  of the nozzle  20  can be raised or lowered as needed. 
         [0030]    In some embodiments the hot gas torch system  1  can comprise other equipment such as one or more shields, grips or other insulating elements to assist in the handling and manipulation of the hot gas torch  10  when applying heated gas  55  to the target site  71  of the substrate  70 . 
         [0031]    The hot gas torch system  1  comprising the hot gas torch  10  and the gas supply  50  can thus be utilized to apply heated gas  55  to a target site  71  of a substrate  70 . The substrate  70  can comprise any metal, alloy, ceramic, polymer, organic or composite material or combinations thereof. In some embodiments the substrate  70  may comprise a worn metal part that has one or more cracks, holes or other sites with missing material that is to be repaired. The target site  71  can comprise any location or locations on the substrate  70  for which heat is to be applied. For example, the target site  71  can comprise a localized area of a substrate  70 , or may comprise an entire surface of the substrate  70 . The hot gas  55  may then be applied to the target site  71  as it exits the internal conduit  25  of the nozzle  20 . Depending on the configuration of the nozzle  20  (e.g., whether the hot gas exits in a single stream or in a variety of streams) and the size and location(s) of the target site  71 , the entire target site  71  can be heated simultaneously, or different parts of the target site  71  can be heated at different intervals. 
         [0032]    In some embodiments a supplemental material  72  may be disposed at the target site  71  of the substrate  70  such that the supplemental material  72  is heated by the hot gas  55 . For example the supplemental material  72  can comprise a filler material (e.g., weld material or braze material) that is disposed at a crack, hole, joint or other location that is to have filler material added. The hot gas  55  can then melt the filler material so that it can subsequently cool and bond with the substrate  70 . When the gas  55  comprises an inert gas, such filler material may be melted and bonded with the substrate  70  without oxidizing either the substrate  70  in a localized inert atmosphere or the filler material to provide a strong, clean joint. 
         [0033]    The supplemental material  72  may also comprise a variety of other materials depending on the heating application. For example the supplemental material  72  can comprise one or more plastics (such as for shrink wrapping around a substrate  70 ), paints or coatings (such as for curing the paint or coating on the substrate  70 ), or other material. 
         [0034]    Referring to  FIG. 5 , a hot gas heating method  100  is illustrated for heating a target site  71  of a substrate  70  such as by using the hot gas torch system  1  discussed above and illustrated in  FIGS. 1-5 . The hot gas heating method  100  first comprises heating the internal conduit  25  using the heating unit  30  in step  110 . As discussed above, a variety of different heating units  30  at a variety of different locations external the internal conduit  25  can be utilized such that the heating unit provides energy (e.g., heat) to the internal conduit  25 . The heating of the internal conduit  25  in step  110  may be continuous or be accomplished in one or more intervals of applying energy. Moreover, as also discussed above, the internal conduit  25  may be heated to any temperature necessary to subsequently heat the gas  55  that will pass through the internal conduit  25 . 
         [0035]    The hot gas heating method  100  further comprises passing gas through the internal conduit  25  such that the gas  55  is heated in step  120 . Specifically, the gas  55  is heated as it travels through the internal conduit  25  from the inlet end  21  to the outlet end  22 . In some embodiments, passing the gas  55  through the internal conduit  25  occurs after the internal conduit  25  is heated in step  110 . In some embodiments, passing the gas  55  through the internal conduit  25  occurs while the internal conduit  25  is being heated in step  110 . Moreover, as discussed above, the gas  55  will become heated based at least in part on the temperature of the internal conduit  25  and the dwell time of the gas  55  as it passes through the internal conduit  25 . Thus, to increase the temperature of the gas  55  when it exits the outlet end  22  of the internal conduit  25 , the internal conduit  25  can be heated to a higher temperature by the heating unit  30  and/or the gas  55  can have a longer dwell time in the internal conduit  25  (such as by increasing the overall length of the internal conduit  25  or decreasing the flow rate of the gas). 
         [0036]    In some embodiments, the hot gas heating method  100  may further comprise measuring the temperature of the gas  55  in step  125 . The temperature of the gas  55  may be measured proximate the outlet end  22  of the internal conduit  25  to understand the relative amount of heat being applied to the target site  71  of the substrate  70 . As illustrated in  FIG. 5 , the heating of the internal conduit  25  in step  110  may then be controlled based at least in part on the temperature of the gas  55  proximate the outlet end  22  of the internal conduit  25 . The heating unit  30  can thereby provide additional energy to the internal conduit  25  if the temperature of the gas  55  is lower than needed and provide less energy to the internal conduit  25  if the temperature of the gas  55  is higher than needed. 
         [0037]    Referring to  FIGS. 1-5 , the hot gas heating method  100  finally comprises heating the target site  71  of the substrate  70  using the gas  55  that exits the outlet end  22  of the internal conduit  25  in step  130 . As discussed above, the target site  71  of the substrate can be heated to any necessary temperature and can depend on, among other things, on the type of substrate  70  and/or the presence of any supplemental material  72  at the target site  71 . For example, when the substrate  70  comprises an alloy substrate that is being repaired with a weld material or a braze material, the weld material or braze material can be heated above its melting temperature so that it can melt and bond with the substrate  70  at the target site  71 . 
         [0038]    It should now be appreciated that a hot gas torch may be combined with a gas supply  50  to form a hot gas torch system that can heat a gas  55  without the use of combustion. By passing the gas through the internal conduit of a nozzle that is heated by a heating unit, the gas can become heated during its dwell time in the internal conduit. The heated gas can then exit the outlet end of the nozzle and be directed to a target site of a substrate to heat the part without combusting. Depending on the type of gas used, the hot gas torch system can locally heat a part of substrate with a local inert atmosphere without the need for placing the entire substrate in a vacuum or chamber. 
         [0039]    While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.