Patent Publication Number: US-9895709-B2

Title: Thermal spraying system

Description:
RELATED APPLICATIONS 
     This application claims is a divisional application of U.S. application Ser. No. 14/737,415 filed on Jun. 11, 2015, which was based on, and claimed priority to Taiwan Application Serial Number 103121185, filed Jun. 19, 2014, and Taiwan Application Serial Number 104115623, filed May 15, 2015, which are herein incorporated by reference. 
    
    
     BACKGROUND 
     Technical Field 
     Embodiments of the present invention relate to a thermal spraying system and apparatus thereof. 
     Description of Related Art 
     Traditional fusion spraying apparatus generally utilizes a guide screw as an extrusion system, which renders the overall apparatus too bulky. Hence, the fusion spraying apparatus can only be fixed during a fusion spraying operation. As a result, the operator has a limited flexibility when operating the fusion spraying apparatus, thus affecting the textile design flexibility. 
     In addition, although there are manufacturers who have developed a blow gun using solvent, adhesive, and short fiber as raw materials. Such kind of blow gun is convenient to operate, but however, the blow gun nozzle is easily blocked and the solvent can easily cause a fire and is harmful to health. At the same time, because the raw materials of the blow gun need to be specially prepared, they are not compatible with the prior art raw material, which in turn limits the commercial value. 
     For the forgoing reasons, there is a need to solve the above-mentioned problem by providing a thermal spraying apparatus. 
     SUMMARY 
     An embodiment of the invention provides a thermal spraying system. The thermal spraying system includes a fixing device, a thermal spraying apparatus, and a motion module. The fixing device is configured for fixing an object to be thermally sprayed. The thermal spraying apparatus is configured for performing a thermal spraying operation to the object to be thermally sprayed. The motion module is configured for driving a relative motion between the thermal spraying apparatus and the fixing device. The thermal spraying apparatus includes a hollow pipe, an extrusion die, a transporting device, a helical pipe, a fluid supplying device, and a heater. The hollow pipe defines an accommodating space in the hollow pipe. The accommodating space is configured to accommodate a raw material. The extrusion die is connected with the hollow pipe. The extrusion die has a nozzle. The nozzle is in spatial communication with the accommodating space. The transporting device is used for moving the raw material to pass through the nozzle. The helical pipe surrounds the hollow pipe. An end of the helical pipe is connected to the nozzle. The fluid supplying device is connected to another end of the helical pipe. The heater encloses the helical pipe and the hollow pipe for heating the helical pipe and the accommodating space. 
     An embodiment of the invention provides a thermal spraying system. The thermal spraying system includes a fixing device, at least one raw material supplying device, a fluid supplying device, a thermal spraying apparatus, and a motion module. The fixing device is configured for fixing an object to be thermally sprayed. The raw material supplying device is configured for supplying a raw material. The fluid supplying device is configured for supplying a fluid. The thermal spraying apparatus is configured for performing a thermal spraying operation to the object to be thermally sprayed. The motion module is configured for driving a relative motion between the thermal spraying apparatus and the fixing device. The thermal spraying apparatus includes an extrusion die, a helical pipe, and a heater. The extrusion die is connected to the raw material supplying device. The extrusion die has a nozzle in spatial communication with the raw material supplying device and the fluid supplying device so that the fluid is able to carry the raw material to be sprayed from the nozzle. The helical pipe surrounds the heater and is in spatial communication with the nozzle and the fluid supplying device so that the fluid from the fluid supplying device flows to the nozzle via the helical pipe and the fluid is heated by utilizing the heater. 
     According to the above embodiments, the thermal spraying apparatus can be operated with three-dimensional thermal spraying technology to form a thermal spraying system. The thermal spraying system utilizing the thermal spraying apparatus has the advantage of lightweight, which does not result in an excessive burden of the thermal spraying motion device so as to effectively extend the service life of the thermal spraying motion device. The present invention thermal spraying apparatus utilizes the piston instead of the prior art screw guide to push the raw material. In addition, since the present invention can utilize the prior art raw material without the necessity of preparing solvent, occupational accidents therefore do not happen to designers and the raw material cost is cheaper. In summary, the present invention thermal spraying apparatus is very light, which allows designers to flexibly design the products in the handheld manner for an extended period of time. 
     It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, 
         FIG. 1  is a side view of a thermal spraying apparatus according to a first embodiment of this invention; 
         FIG. 2  is a perspective view of the thermal spraying apparatus in  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the thermal spraying apparatus in  FIG. 1 ; 
         FIG. 4  is a cross-sectional view of a thermal spraying apparatus according to a second embodiment of this invention; 
         FIG. 5  is a perspective view of a thermal spraying apparatus according to a third embodiment of this invention; 
         FIG. 6  is a cross-sectional view of the thermal spraying apparatus in  FIG. 5 ; 
         FIG. 7  is a cross-sectional view of a thermal spraying apparatus according to a fourth embodiment of this invention; 
         FIG. 8A  is a schematic diagram of a thermal spraying system according to a fifth embodiment of this invention; 
         FIG. 8B  is a schematic diagram of another thermal spraying system according to the fifth embodiment of this invention; 
         FIG. 8C  is a schematic diagram of still another thermal spraying system according to the fifth embodiment of this invention; 
         FIG. 9  is a cross-sectional view of the thermal spraying apparatus in  FIG. 8A ; 
         FIG. 10A  is a schematic diagram of a thermal spraying system according to a sixth embodiment of this invention; 
         FIG. 10B  is a schematic diagram of another thermal spraying system according to the sixth embodiment of this invention; 
         FIG. 10C  is a schematic diagram of still another thermal spraying system according to the sixth embodiment of this invention; 
         FIG. 11  is a cross-sectional view of the thermal spraying apparatus in  FIG. 10A ; 
         FIG. 12  is an enlarged view of an extrusion die of a thermal spraying system according to a seven embodiment of this invention; 
         FIG. 13  is a cross-sectional view of a thermal spraying apparatus according to some embodiments of this invention; and 
         FIG. 14  is a top view during an operation of the thermal spraying apparatus of  FIG. 13 . 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically depicted in order to simplify the drawings. 
     First Embodiment 
     In order to solve the problem that the prior art fusion spraying apparatus is too bulky, which in turn limits the location where the fusion spraying apparatus can be used and makes the fusion spraying apparatus not portable, and also eliminate the health concern and safety concern of the blow gun, a thermal spraying apparatus is provided according to a first embodiment of the present invention.  FIG. 1  is a side view of a thermal spraying apparatus  100  according to a first embodiment of this invention.  FIG. 2  is a perspective view of the thermal spraying apparatus  100  in  FIG. 1 .  FIG. 3  is a cross-sectional view of the thermal spraying apparatus  100  in  FIG. 1 . As shown in  FIG. 1  to  FIG. 3 , the thermal spraying apparatus  100  includes a hollow pipe  110 , an extrusion die  120 , a piston  130 , a helical pipe  140 , a heater  150 , and a fluid supplying device  500 . The hollow pipe  110  defines an accommodating space  112  therein. The accommodating space  112  is configured to accommodate a raw material. The extrusion die  120  is connected with the hollow pipe  110 . The extrusion die  120  has a nozzle  122 . The nozzle  122  is in spatial communication with the accommodating space  112 . The piston  130  is movably accommodated in the accommodating space  112  to push the raw material to pass through the nozzle  122 . The piston  130  can therefore be referred to as a transporting device for moving the raw material to pass through the nozzle  122  in some embodiments. Stated differently, the thermal spraying apparatus  100  includes a transporting device for moving the raw material, and such a transporting device includes the piston  130  that transports the raw material in a pushing manner. The hollow pipe  110  is surrounded by the helical pipe  140 . An end of the helical pipe  140  is connected to the nozzle  122  via auxiliary airflow passages  124 . The fluid supplying device  500  is connected with another end of the helical pipe  140  via a pipe  510 . The heater  150  encloses the helical pipe  140  and the hollow pipe  110  and is configured to heat the helical pipe  140  and the accommodating space  112 . 
     According to the present embodiment, the thermal spraying apparatus  100  includes a propulsion passage  160 . The accommodating space  112  is divided into a front part  116  closer to the nozzle  122  and a back part  118  farther from the nozzle  122  by the piston  130 . An end of the propulsion passage  160  is connected to the fluid supplying device  500  via the pipe  510 . Another end of the propulsion passage  160  is in spatial communication with the back part  118  so that fluid provided by the fluid supplying device  500  is able to push the piston  130  to move toward the nozzle  122 . 
     In the present embodiment, the thermal spraying apparatus  100  is connected to the fluid supplying device  500  via the single pipe  510 , and the fluid is then separately guided into the propulsion passage  160  and the helical pipe  140  in the thermal spraying apparatus  100 . In this manner, inconvenience of using the thermal spraying apparatus  100  because of complexity caused by multiple pipes is avoided. However, the present invention is not limited in this regard. In some embodiments of the present invention, one pair of pipes may be utilized to respectively connect the propulsion passage  160  and the helical pipe  140  to the fluid supplying device  500 . 
     When a designer uses the thermal spraying apparatus  100  in a handheld manner, the raw material can be placed into the front part  116 . At this time, the fluid provided by the fluid supplying device  500  pushes the piston  130  to move toward the nozzle  122  so that the piston  130  pushes the raw material to move toward the nozzle  122 . The raw material in the hollow pipe  110  is heated by the heater  150 . Hence, the raw material will gradually melt. In addition to that, a temperature of the fluid in the helical pipe  140  is increased because the fluid in the helical pipe  140  is also heated by the heater  150 . When the heated fluid is sprayed from the nozzle  122 , the molten raw material will be carried and sprayed out with the heated fluid so as to form a thermal spraying textile. According to the present embodiment, the fluid in the helical pipe  140  is heated to raise the temperature of the fluid. Thus, blockage to the nozzle  122  resulting from solidification of the raw material due to cooling when the raw material is sprayed out is avoided. 
     When the heater  150  performs heating, the fluid in the helical pipe  140  carries thermal energy to a position of the hollow pipe  110  close to the extrusion die  120 , such that a temperature inside the hollow pipe  110  gradually increases from a position far from the extrusion die  120  to a position close to the extrusion die  120 . Such a configuration allows a user&#39;s handheld position and an inlet of the hollow pipe  110  away from the extrusion die  120  to be maintained at relative low temperatures, which facilitates users to operate or fill the raw material. 
     According to one embodiment of the present invention, a total length of the hollow pipe  110  is 233 millimeters (mms). A temperature of the heater  150  is set to be 200° C. A material of the raw material is polypropylene (PP). At a position 78-233 millimeters from the extrusion die  120 , a temperature of the raw material is only 75° C. and the raw material has not yet melted. At a position 39-78 millimeters from the extrusion die  120 , the temperature of the raw material is increased to 160° C. and the raw material has melted to become a fluid having a viscosity higher than 100 poise. At a position 0-39 millimeters from the extrusion die  120 , the temperature of the raw material is further increased to 200° C. and the raw material has melted to become a fluid having a viscosity ranging from 10 poise to 21 poise. 
     According to another embodiment of the present invention, the total length of the hollow pipe  110  is 233 millimeters. The temperature of the heater  150  is set to be 230° C. The material of the raw material is thermoplastic polyurethane (TPU). At the position 78-233 millimeters from the extrusion die  120 , the temperature of the raw material is only 100° C. and the raw material has not yet melted. At the position 39-78 millimeters from the extrusion die  120 , the temperature of the raw material is increased to 180° C. and the raw material has melted to become a fluid having a viscosity higher than 100 poise. At the position 0-39 millimeters from the extrusion die  120 , the temperature of the raw material is further increased to 230° C. and the raw material has melted to become a fluid having a viscosity ranging from 10 poise to 21 poise. 
     In the present embodiment, the fluid supplying device  500  may be an air compressor. Airflow provided by the air compressor can pass through the pipe  510  and the propulsion passage  160  to push the piston  130  to move toward the nozzle  122 . In addition, the airflow provided by the air compressor can pass through the pipe  510 , the helical pipe  140 , and the auxiliary airflow passages  124 , thereby reaching the nozzle  122  to carry the molten raw material to be sprayed out. 
     It is noted that the above-mentioned fluid supplying device  500  is not limited to the air compressor. An air package or other device being able to provide fluid with a thrust force can also serve as the fluid supplying device  500 . Those of ordinary skill of the art may flexibly select the adequate fluid supplying device  500  depending on practical needs. 
     In order to control the spraying action of the raw material, the present invention thermal spraying apparatus  100  further includes a switching valve  165 . The switching valve  165  is connected between the accommodating space  112  and the nozzle  122 . When the switching valve  165  is turned on, the raw material can be transported from the accommodating space  112  to the nozzle  122  via the switching valve  165 . When the switching valve  165  is turned off, the raw material can not be transported to the nozzle  122  via the switching valve  165 . As such, users can control whether the nozzle  122  sprays the raw material by controlling the switching valve  165 . In practical applications, the above switching valve  165  may be an electric control switching valve and/or a pneumatic switching valve. 
     According to the present embodiment, the thermal spraying apparatus  100  includes a housing  170  and a handheld grip  180 . The housing  170  at least encloses the hollow pipe  110 , the helical pipe  140 , and the heater  150 . The handheld grip  180  is connected to the housing  170 . The housing  170  is configured to protect interior devices. The handheld grip  180  is convenient for a designer to hold. 
     Additionally, the housing  170  according to the present embodiment may further extend to surround the nozzle  122  so as to serve as a shield. The impact of splash on surroundings is thus avoided. In the present embodiment, the shield is one part of the housing  170 . However, in other embodiments, the shield may be an element independent of the housing  170 , and the housing  170  and the shield are detachably connected. Those of ordinary skill of the art may flexibly select a configuration depending on practical needs. 
     In the present embodiment, the thermal spraying apparatus  100  may further include a temperature controller. For example, the temperature controller may a built-in temperature controller  172 . The built-in temperature controller  172  is electrically connected to the heater  150  for controlling a temperature of the heater  150 . In greater detail, the built-in temperature controller  172  according to the present embodiment may be located on the housing  170  or inside the handheld grip  180 . When the built-in temperature controller  172  detects that the temperature will soon be unduly high, it will actively control the heater  150  to stop raising temperature. When the built-in temperature controller  172  detects that the temperature will soon be unduly low, it will actively control the heater  150  to raise temperature. 
     According to the present embodiment, the raw material may be a rod-shaped raw material matching with a size of the accommodating space  112 . Since no air exists in the rod-shaped raw material, the intermittent and unsmooth spraying because of the presence of air can be prevented when the raw material is sprayed from the nozzle  122 . 
     As shown in  FIG. 3 , the thermal spraying apparatus  100  may further include a heat-insulating element  176  in the present embodiment. The heat-insulating element  176  encloses the heater  150 , the helical pipe  140 , and the hollow pipe  110 . By enclosing the heater  150  with the heat-insulating element  176 , not only the heat energy leakage does not occur, but the designer also does not get burned due to high temperature. 
     Second Embodiment 
       FIG. 4  is a cross-sectional view of a thermal spraying apparatus  100  according to a second embodiment of this invention. The major difference between the present embodiment and the first embodiment is that the thermal spraying apparatus  100  according to the present embodiment further includes a pressure controller  600 . The pressure controller  600  is connected to the fluid supplying device  500  for controlling a pressure of the fluid supplied by the fluid supplying device  500 . Hence, the closer the piston  130  is to the nozzle  122 , the lower pressure the fluid has. As a result, even though the closer the piston  130  is to the nozzle  122 , the less amount of the raw material is in the front part  116 , which possibly causes a moving speed of the piston  130  to increase, however, the tendency of increasing moving speed of the piston  130  is effectively suppressed because the piston  130  is pushed by a reduced fluid pressure. The uneven extrusion speed of the raw material caused by the increasing moving speed of the piston  130 , which in turn impacts the thermal spraying effect, is prevented. For example, the pressure controller  600  may be a pressure valve. The pressure valve is disposed on the fluid supplying device  500  or the pipe  510  to control the fluid pressure. 
     Since other relevant structures and operation details are the same as those of the first embodiment, a description in this regard is not provided. 
     Third Embodiment 
       FIG. 5  is a perspective view of a thermal spraying apparatus  100  according to a third embodiment of this invention.  FIG. 6  is a cross-sectional view of the thermal spraying apparatus  100  in  FIG. 5 . The major difference between the present embodiment and the first embodiment is that the thermal spraying apparatus  100  according to the present embodiment further includes a pushrod  134 . The pushrod  134  is connected to the piston  130  and extends outside the accommodating space  112 . In practical applications, the pushrod  134  moves with the piston  130 . Hence, the designer can be informed of the residual amount of the raw material, so as to replenish the raw material timely. 
     In addition, except for the rod-shaped raw material, powder row material or particle raw material may be adopted in the present embodiment. In greater detail, since air is in between the powder or particle raw material, the thermal spraying apparatus  100  may include an air passage  132  in some embodiments, as shown in  FIG. 5  and  FIG. 6 . The air passage  132  passes through the piston  130  and the pushrod  134  and is in spatial communication with the front part  116  and an outside of the thermal spraying apparatus  100  to expel the air in between the raw material to the outside of the thermal spraying apparatus  100 , so as to avoid intermittent spraying operations caused by the air in between the raw material. In greater detail, when the piston  130  pushes the raw material, the piston  130  will extrude the raw material located in the front part  116 . The air in the raw material will be expelled to the outside of the thermal spraying apparatus  100  via the air passage  132  after the air in the raw material is extruded, so the unsmooth spraying operation will not occur. 
     According to the present embodiment, the temperature controller of the thermal spraying apparatus  100  may be an external temperature controller  174 . The external temperature controller  174  is detachably and electrically connected to the heater  150  for controlling the temperature of the heater  150 . In greater detail, the external temperature controller  174  according to the present embodiment may be located outside the housing  170  and the handheld grip  180 . When the external temperature controller  174  detects that the temperature will soon be unduly high, it will actively control the heater  150  to stop raising temperature. When the external temperature controller  174  detects that the temperature will soon be unduly low, it will actively control the heater  150  to raise temperature. 
     Since other relevant structures and operation details are the same as those of the first embodiment, a description in this regard is not provided. 
     Fourth Embodiment 
       FIG. 7  is a cross-sectional view of a thermal spraying apparatus  100  according to a fourth embodiment of this invention. The major difference between the present embodiment and the third embodiment is that the thermal spraying apparatus  100  includes a piston control device  800 . The piston control device  800  is configured to control the piston  130  to push the raw material at a constant speed so that the uneven spraying speed of the raw material, which in turn impacts the thermal spraying effect, is prevented. In greater detail, the piston control device  800  controls the piston  130  to move toward the nozzle  122  at a constant speed by the pushrod  134  so that the piston  130  is able to push the raw material in the front part  116  at a constant speed. 
     In some embodiments, the piston control device  800  includes a stepper motor  810 . The stepper motor  810  has an output shaft  812 . The output shaft  812  is connected to the pushrod  134  and the pushrod  134  is configured to control the piston  130  to move in the accommodating space  112  at a constant speed. For example, the pushrod  134  may be a guide screw. The output shaft  812  of the stepper motor  810  can be engaged with the guide screw. The guide screw can be driven to rotate when the output shaft  812  rotates, so as to push the piston  130 . 
     Since other relevant structures and operation details are the same as those of the first embodiment, a description in this regard is not provided. 
     Fifth Embodiment 
     The thermal spraying apparatus  100  may also cooperate with the thermal spraying technology to form a thermal spraying system. A description is provided with reference to  FIG. 8A  and  FIG. 9 .  FIG. 8A  is a schematic diagram of a thermal spraying system  200  according to a fifth embodiment of this invention.  FIG. 9  is a cross-sectional view of the thermal spraying apparatus  100  in  FIG. 8A . The thermal spraying system  200  includes a fixing device  210 , the thermal spraying apparatus  100 , and a motion module. The fixing device  210  is configured to fix an object to be thermally sprayed  700 . The thermal spraying apparatus  100  is configured to perform a thermal spraying operation to the object to be thermally sprayed  700 . The motion module is configured to drive a relative motion between the thermal spraying apparatus  100  and the fixing device  210 . For example, the motion module may include a thermal spraying motion device  220 . The thermal spraying motion device  220  is connected to the thermal spraying apparatus  100  to allow the thermal spraying apparatus  100  to move in three dimensions relative to the motionless object to be thermally sprayed  700 , such as dimension X, dimension Y, dimension Z, the rotation direction C, the reverse rotation direction C′, the pitch direction A, or combinations of the three dimensions and the rotation directions, as shown in  FIG. 8A .  FIG. 8B  is a schematic diagram of another thermal spraying system according to the fifth embodiment of this invention. In another embodiment, the thermal spraying apparatus  100  may be maintained static and the object to be thermally sprayed  700  moves in dimension X, dimension Y, dimension Z, the rotation direction C, the reverse rotation direction C′, the pitch direction A, or combinations of the three dimensions and the rotation directions, as shown in  FIG. 8B . A description is provided with reference to  FIG. 8C .  FIG. 8C  is a schematic diagram of still another thermal spraying system according to the fifth embodiment of this invention. In still another embodiment, each of the thermal spraying apparatus  100  and the object to be thermally sprayed  700  can, as shown in  FIG. 8C , move in dimension X, dimension Y, dimension Z, the rotation direction C, the reverse rotation direction C′, the pitch direction A, or combinations of the three dimensions and the rotation directions so as to achieve a three-dimensional motion independent of each other to perform the thermal spraying operation. Three-dimensional motion methods can be based on designs of various mechanisms of the thermal spraying apparatus  100  and the object to be thermally sprayed  700  of the thermal spraying system  200 . The motion methods provided by the above embodiment only serve as examples and are not intended for limiting the present invention. Those of ordinary skill in the art may flexibly select the motion methods of the thermal spraying apparatus  100  and the object to be thermally sprayed  700  as required by practical needs, so as to achieve reciprocal three-dimensional motion methods relative to each other, which are not limited to the embodiments of the present invention. 
     In other words, the motion module of the thermal spraying system  200  can further includes an object motion device  212 . The object motion device  212  is connected to the fixing device  210  to allow the object to be thermally sprayed  700  to move in at least a second dimension relative to the thermal spraying apparatus  100 . A first dimension and the second dimension are linearly independent of each other. Since the first dimension is linearly independent of the second dimension, the thermal spraying apparatus  100  is able to spay various positions on the object to be thermally sprayed  700  by the cooperation of the object motion device  212  and the thermal spraying motion device  220 . 
     It should be understood that the above motion methods only serve as examples and are not intended for limiting the present invention. Those of ordinary skill in the art may flexibly select the motion methods of the thermal spraying apparatus  100  and the object to be thermally sprayed  700  as required by practical needs. For example, in some embodiments of the present invention, the object motion device  212  may be omitted, and the motions in various dimensions are independently achieved by the thermal spraying motion device  220 . 
     As shown in  FIG. 9 , in the present embodiment, since the thermal spraying apparatus  100  is connected to the thermal spraying motion device  220  (see  FIG. 8C ), there is no necessity to operate in a handheld manner. Under such situations, the handheld grip  180  may be omitted. Of course, if in some situations, the handheld operation is expected to be retained, the handheld grip  180  can be included. 
     The present invention thermal spraying system  200  can be used to manufacture a variety of industrial products. For example, when the present invention thermal spraying system  200  is configured to manufacture vehicle seats, the object to be thermally sprayed  700  may be a seat body or a seat mold. The thermal spraying system  200  can thermally spray a cousin on the seat body or the seat mold. In addition, when the present invention thermal spraying system  200  is configured to manufacture uppers, the object to be thermally sprayed  700  may be a shoe last. The thermal spraying system  200  can thermally spray an upper on the shoe last. 
     Since other relevant structures and operation details are the same as those of the first embodiment, a description in this regard is not provided. 
     Sixth Embodiment 
     The present invention further provides another thermal spraying system. Similarly, the thermal spraying system also can move relative to the object to be thermally sprayed and perform a thermal spraying operation. A description is provided with reference to  FIG. 10A  and  FIG. 11 .  FIG. 10A  is a schematic diagram of a thermal spraying system  200  according to a sixth embodiment of this invention.  FIG. 11  is a cross-sectional view of the thermal spraying apparatus  100  in  FIG. 10A . As shown in  FIG. 10A  and  FIG. 11 , the major difference between the present embodiment and the fifth embodiment is that the thermal spraying system  200  according to the present embodiment can further include a raw material supplying device  240 . The raw material supplying device  240  is configured to supply the raw material to the thermal spraying apparatus  100 . The extrusion die  120  of the thermal spraying apparatus  100  is connected to the raw material supplying device  240 . The nozzle  122  of the extrusion die  120  is in spatial communication with the raw material and the fluid, such that the fluid can carry the raw material to be sprayed out of the nozzle  122 . 
     As compared with the third embodiment, the raw material supplying device  240  according to the present embodiment can continuously supply the raw material to the nozzle  122  without the necessity of manually replenishing the raw material to the thermal spraying apparatus  100 . In the present embodiment, the foregoing raw material supplying device  240  may be an extruder. In addition, the raw material supplying device  240  has a raw material supplying pipe  242 . The raw material supplying pipe  242  is connected to the thermal spraying apparatus  100 . The raw material supplying pipe  242  is a flexible pipe. In such configuration, the thermal spraying apparatus  100  is able to move relative to the raw material supplying device  240 . In other words, when the thermal spraying motion device  220  drives the thermal spraying apparatus  100  to move, the raw material supplying device  240  does not need to move together, thus reducing the load of the thermal spraying motion device  220 . 
     The thermal spraying apparatus  100  can further include a switching valve  260 . The switching valve  260  is connected between the raw material supplying device  240  and the nozzle  122 . When the switching valve  260  is turned on, the raw material can be transported from the raw material supplying pipe  242  to the nozzle  122  via the switching valve  260  and a raw material passage  126 . When the switching valve  260  is turned off, the raw material can not be transported to the nozzle  122  via the switching valve  260 . As such, users can control whether the nozzle  122  sprays the raw material by controlling the switching valve  260 . In practical applications, the foregoing switching valve  260  may be an electric control switching valve and/or a pneumatic switching valve. 
     In addition, the thermal spraying apparatus  100  may further include a synchronous device  270  according to the present embodiment. The synchronous device  270  is configured to control the switching valve  260  and the raw material supplying device  240  to operate simultaneously. That is, when the switching valve  260  is turned on, the raw material supplying device  240  is activated. When the switching valve  260  is turned off, the raw material supplying device  240  is deactivated. 
     Additionally, in the present embodiment, the helical pipe  140  surrounds the heater  150  so that the heater  150  can be configured to heat the fluid in the helical pipe  140 . In greater detail, as compared with the previous embodiments, since the accommodating space  112  in the hollow pipe  110  no longer needs to accommodate the raw material, the manufacturer can selectively install the heater  115  in the accommodating space  112  in the hollow pipe  110  to further decrease the volume of the thermal spraying apparatus  100 . 
     Other relevant structures and operation details of the thermal spraying apparatus according to the present embodiment are similar to those of the fifth embodiment. In greater detail, the thermal spraying system  200  includes the fixing device  210 , the thermal spraying apparatus  100 , and the thermal spraying motion device  220 . The fixing device  210  is configured to fix the object to be thermally sprayed  700 . The thermal spraying apparatus  100  is configured to perform the thermal spraying operation to the object to be thermally sprayed. The thermal spraying motion device  220  is connected to the thermal spraying apparatus  100  and configured for allowing the thermal spraying apparatus  100  to move in three dimensions relative to the motionless object to be thermally sprayed  700 , such as dimension X, dimension Y, dimension Z, the rotation direction C, the reverse rotation direction C′, the pitch direction A, or combinations of the three dimensions and the rotation directions, as shown in  FIG. 10A . A description is provided with reference to  FIG. 10B .  FIG. 10B  is a schematic diagram of another thermal spraying system according to the sixth embodiment of this invention. In another embodiment, the thermal spraying apparatus  100  may be maintained static and the object to be thermally sprayed  700  moves in dimension X, dimension Y, dimension Z, the rotation direction C, the reverse rotation direction C′, the pitch direction A, or combinations of the three dimensions and the rotation directions, as shown in  FIG. 10B , to perform the thermal spraying operation. A description is provided with reference to  FIG. 10C .  FIG. 10C  is a schematic diagram of still another thermal spraying system according to the sixth embodiment of this invention. In still another embodiment, each of the thermal spraying apparatus  100  and the object to be thermally sprayed  700  can, as shown in  FIG. 10C , moves in dimension X, dimension Y, dimension Z, the rotation direction C, the reverse rotation direction C′, the pitch direction A, or combinations of the three dimensions and the rotation directions so as to achieve a three-dimensional motion independent or each other to perform the thermal spraying operation. Three-dimensional motion methods can be based on designs of various mechanisms of the thermal spraying apparatus  100  and the object to be thermally sprayed  700  of the thermal spraying system  200 . The motion methods provided by the foregoing embodiment only serve as examples and are not intended for limiting the present invention. Those of ordinary skill in the art may flexibly select the motion methods of the thermal spraying apparatus  100  and the object to be thermally sprayed  700  as required by practical needs to achieve reciprocal three-dimensional motion methods relative to each other, which are not limited to the embodiments of the present invention. 
     Seventh Embodiment 
     The present invention still provides another thermal spraying system.  FIG. 12  is an enlarged view of the extrusion die  120  of a thermal spraying system. As shown in  FIG. 12 , the major difference between the present embodiment and the sixth embodiment is that a number of the raw material supplying devices  240  is plural and a plurality of raw material supplying devices  240  are respectively configured to supply different raw materials to the nozzle  122 . In this manner, spraying a multi-constituent raw material can be realized. 
     In greater detail, as shown in  FIG. 12 , the number of the raw material supplying devices  240  is two. Each of the two raw material supplying devices  240  includes the raw material supplying pipe  242 . The nozzle  122  includes a first discharge port  122   a  and a second discharge port  122   b  being respectively in spatial communication with the raw material supplying pipes  242  of the two raw material supplying devices  240 . Hence, the raw materials provided by the two raw material supplying devices  240  can be sprayed out respectively via the first discharge port  122   a  and the second discharge port  122   b  so as to realize multi-constituent raw material spraying. 
     In some embodiments, as shown in  FIG. 12 , the first discharge port  122   a  surrounds the second discharge port  122   b . One of the raw material supplying devices  240  further includes a connecting pipe  244 . The connecting pipe  244  is connected to the second discharge port  122   b , so as to guide the raw material provided by the one of the raw material supplying devices  240  to be directly sprayed out from the second discharge port  122   b  without passing through the first discharge port  122   a . Another one of the raw material supplying devices  240  does not include any connecting pipe and the raw material supplying pipe  242  of the another one of the raw material supplying devices  240  is in spatial communication with the first discharge port  122   a , so as to directly spray the raw material from the first discharge port  122   a.    
     In some embodiments, it is not necessary to adopt the plurality of raw material supplying devices  240  to realize the multi-constituent thermal spraying operation by using a multi-constituent raw material. Rather, a multi-constituent rod-shaped raw material can be placed in the front part  116  as shown in  FIG. 9  to allow the multi-constituent rod-shaped raw material to melt into a molten state by the heater  150 , and the molten multi-constituent rod-shaped raw material can be sprayed from the nozzle  120  when the piston  130  pushes the molten multi-constituent rod-shaped raw material. 
       FIG. 13  is a cross-sectional view of a thermal spraying apparatus according to some embodiments of this invention.  FIG. 14  is a top view during an operation of the thermal spraying apparatus of  FIG. 13 . As shown in  FIGS. 13 and 14 , a transporting device  900  can be included to move a raw material F toward the extrusion die  120  to pass through the nozzle  122  in a roll-to-roll manner. For example, the transporting device  900  includes motors  910  and rollers  914 . The motors  910  have parallel output shafts  912 . The rollers  914  are axially connected to respective output shafts  912  and hold the raw material F therebetween. The motors  910  actuate the output shafts  912  to rotate in opposite directions D 1  and D 2 , as shown in  FIG. 14 , so that the rollers  914  can rotate in the opposite directions D 1  and D 2  as well. By using such actuation, the raw material F can be moved toward the extrusion die  120  in a roll-to-roll manner. The raw material F can be, for example, plastic fibers, which are advantageous to be moved in a roll-to-roll manner. In some embodiments, these plastic fibers can be formed by an external extruder in advance, so an extruder for forming the plastic fibers can be absent in this thermal spraying apparatus. Further, since the extruder for forming the plastic fibers can be absent in this thermal spraying apparatus, a heat source for this extruder can be absent as well. Therefore, temperature in a rolling entrance of the rollers  914  can remain not elevated, or remain low relative to that in the extrusion die  120 . Such stable temperature is advantageous to protect the motors  910 . Moreover, the plastic fibers are beneficial to be controlled to move toward the extrusion die  120  due to their fiber shape. In some embodiments, the motors  910  can be, for example, stepper motors, and the rollers  914  can be, for example, gears. 
     Embodiments 
     In the following, several embodiments according to the present invention are described for illustrating that the thermal spraying apparatus  100  according to the above embodiments of the present invention can certainly configured to thermally spray fibers. 
     In the first embodiment, the employed thermal spraying apparatus  100  is the thermal spraying apparatus  100  shown in  FIG. 2 . The raw material is thermoplastic polyurethane (TPU), which has a brand name of Kutane 300 and is produced by Kuo Ching Chemical Co., Ltd. The temperature of the heater  150  is set to be 230° C. A pressure of the fluid supplying device  500  (in greater detail, air compressor) is set to be 5 kg/cm 2 . Under such conditions, fibers thermally sprayed by the thermal spraying apparatus  100  have a fineness ranging from 2 μm to 5 μm. 
     In the second embodiment, the employed thermal spraying apparatus  100  is the thermal spraying apparatus  100  shown in  FIG. 5 . The raw material is polypropylene (PP), which has a melt flow index (MFI) of 1500 and is produced by Exxon Mobile Corp. The temperature of the heater  150  is set to be 200° C. The pressure of the fluid supplying device  500  (in greater detail, air compressor) is set to be 3 kg/cm 2 . Under such conditions, fibers thermally sprayed by the thermal spraying apparatus  100  have the fineness ranging from 5 μm to 10 μm. 
     In the third embodiment, the employed thermal spraying apparatus  100  is the thermal spraying apparatus  100  shown in  FIG. 5 . The raw material is a mixture of polypropylene (PP) and polyolefin elastomer, which is produced by Idemitsu Kosan Co., Ltd and has a brand name of L-MODU. A mixing ratio is 50:50. Polypropylene has the melt flow index of 1500 and is produced by Exxon Mobile Corp. The temperature of the heater  150  is set to be 200° C. The pressure of the fluid supplying device  500  (in greater detail, air compressor) is set to be 4 kg/cm 2 . Under such conditions, fibers thermally sprayed by the thermal spraying apparatus  100  have the fineness ranging from 10 μm to 15 μm. 
     In summary, the thermal spraying apparatus  100  according to the foregoing embodiments of the present invention can be operated independently in the handheld manner, or can cooperate with three-dimensional thermal spraying technology to form a thermal spraying system  200 . The thermal spraying apparatus  100  can thermally spray fibers on any object. It is characterized by having no trace of sewing, process reduction, recyclable waste material, no solvent, and the products being lightweight, soft, comfortable, and breathable. Both the manufacturing and utilization satisfy eco-friendly principles and can be applied to fashion garments, UV protection, reflective material, fabric bonding, medical plaster and bandages, medical patches, medical supplies, packaging cushion materials, stage design, and heat-insulating acoustic wall. 
     Although the present invention has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.