Patent Publication Number: US-11041618-B2

Title: Infrared radiation heater

Description:
TECHNICAL FIELD 
     The present invention relates to an infrared radiation heater. 
     BACKGROUND ART 
     There has been known an infrared radiation heater including a burner as a combustion device for combusting air-fuel mixture made by mixing fuel with air in the combustion chamber, and a radiator for emitting infrared radiation provided in either of the combustion chambers (see, for example, Patent Literature 1). 
     The infrared radiation heater disclosed in Patent Literature 1 emits infrared radiation by burning the air-fuel mixture from the burner in the combustion chamber to shoot flames at the radiator so that the radiator turns red. The burner used here is a gun type burner configured to shoot flames at the radiator in front of the burner. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL1: Japanese Patent Application Laid-Open No. 2004-270956 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     Conventional infrared radiation heaters, such as the infrared radiation heater disclosed in Patent Literature 1 cannot evenly heat the whole radiator because the burner is configured to shoot flames at the radiator in front of the burner, and therefore it is not possible to improve the infrared radiation efficiency. In addition, a conventional infrared radiation heater has a problem of so-called “backfire” where the flames produced by the burner returns to the burner to burn the fuel, which causes a malfunction. 
     It is therefore an object of the present invention to provide an infrared radiation heater capable of improving the infrared radiation efficiency while preventing a malfunction due to the flame produced by a combustion device. 
     Solution to Problem 
     An aspect of the present invention provides an infrared radiation heater including: a combustion chamber having a combustion space that is open on one side; a combustion device provided in the combustion chamber and configured to combust air-fuel mixture made by mixing fuel with air; and a radiator configured to be heated by heat generated from the combustion device and including a radiation plane configured to emit infrared radiation. The combustion device includes: a nozzle provided in a flow path of the air, and configured to inject the fuel; a tubular body including a side surface that faces a direction with a predetermined angle with respect to the radiation plane, and a plurality of voids being formed on the side surface; and an ignition device provided outside of the tubular body and configured to ignite the air-fuel mixture. The air-fuel mixture flows into the tubular body from a first end of the tubular body in the nozzle side, and the tubular body releases the air-fuel mixture from the voids into the combustion chamber. 
     In the infrared radiation heater, the voids may be formed on a side surface of the tubular body in a circumferential direction. 
     In the infrared radiation heater, the voids may be formed in a mesh pattern. 
     In the infrared radiation heater, the combustion device may include a heat insulator provided at a second end of the tubular body, and configured to insulate between the tubular body and the radiator, and the radiator may be located to face the heat insulator. 
     In the infrared radiation heater, an impeller may be provided in the flow path of the air to generate a swirl flow in the air-fuel mixture flowing through the tubular body. 
     In the infrared radiation heater, the impeller may be a fixed type impeller made of a plate material. 
     According to the present invention, it is possible to improve the infrared radiation efficiency of the infrared radiation heater while preventing a malfunction due to the flame projected from the combustion device. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic view illustrating an infrared radiation heater according to an embodiment of the present invention; 
         FIG. 2  is a front view illustrating the infrared radiation heater illustrated in  FIG. 1 ; 
         FIG. 3  is a side cross-sectional view illustrating the infrared radiation heater illustrated in  FIG. 1 ; 
         FIG. 4  is a side view illustrating a combustion device of the infrared radiation heater illustrated in  FIG. 1 ; 
         FIG. 5  is a side view illustrating a burner head of the combustion device illustrated in  FIG. 4 ; 
         FIG. 6  is a front view illustrating the burner head illustrated in  FIG. 5 ; 
         FIG. 7  is a rear view illustrating the burner head illustrated in  FIG. 5 ; 
         FIG. 8  is a plan view illustrating the burner head illustrated in  FIG. 5 ; and 
         FIG. 9  is a side cross-sectional view illustrating the burner head illustrated in  FIG. 5 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 
     &lt;Configuration of Infrared Radiation Heater&gt; 
       FIG. 1  is a schematic view illustrating an infrared radiation heater  1  according to an embodiment of the present invention. As illustrated in  FIG. 1 , the infrared radiation heater  1  includes a radiator  2  configured to emit radiant heat; a louver  3  configured to control the direction of the radiant heat or warm air from the radiator  2 ; a casing  4  configured to accommodate a combustion chamber  21  and a combustion device  6  described later; and a frame  5  configured to support the casing  4 . Here, the infrared radiation heater  1 , the combustion chamber  21 , and the combustion device  6  correspond to “infrared radiation heater”, “combustion chamber”, and “combustion device” recited in the claims, respectively. 
     The frame  5  includes a side support  51  configured to support each side surface of the casing  4 , and a pair of wheels  53  provided on the bottom of the frame  5  to help carry the infrared radiation heater  1 . 
       FIG. 2  is a front view illustrating the infrared radiation heater  1  illustrated in  FIG. 1 .  FIG. 3  is a side cross-sectional view illustrating the infrared radiation heater  1 . As illustrated in  FIGS. 2 and 3 , the infrared radiation heater  1  includes the combustion chamber  21  provided in the casing  4 , and the combustion device  6  configured to combust fuel in the center of a combustion space  22  in the combustion chamber  21 . 
     The combustion chamber  21  is made of a material with high heat insulating properties, for example, a heat insulating material. The combustion chamber  21  includes a bottom, and an opening on the opposite side of the bottom. The combustion chamber  21  includes the combustion space  22  as space in which the combustion device  6  combusts fuel. With the present embodiment, the combustion chamber  21  has a truncated cone shape where the side surface inclines from the approximately circular bottom to the opening. Here, with the present embodiment, the shape of the combustion chamber  21  of the infrared radiation heater  1  is not limited to the truncated cone as long as the combustion chamber includes the bottom, the side surface and the opening. 
     The radiator  2  is provided on (or in) the opening of the combustion chamber  21 . The radiator  2  is a dome-like member as a convex in the direction in which the infrared radiation is emitted, opposite to the combustion device  6 . The radiator  2  is made of a material with a high emissivity of infrared radiation, for example, heat-resistant stainless steel. The radiator  2  has a radiation plane to emit heat. The radiation plane of the radiator  2  is shaped to fit the opening of the combustion chamber  21 . The radiator  2  turns red by the heat of the flame generated by the combustion device  6 , so that infrared radiation is emitted from the radiation plane to the outside. Here, for the infrared radiation heater  1  according to the present embodiment, the shape of the radiation plane is not limited to the dome shape. 
     &lt;Configuration of Combustion Device&gt; 
     Next, the configuration of the combustion device  6  of the infrared radiation heater  1  will be described.  FIG. 4  is a side view illustrating the combustion device  6  of the infrared radiation heater  1 . As illustrated in  FIG. 4 , the combustion device  6  includes a burner head  60 , a fan  7 , a gas pipe connector  8 . 
     The burner head  60  combusts air-fuel mixture made by mixing propane gas introduced from the gas pipe connector  8  with the air supplied from the fan  7  in the combustion space  22  located outside the burner head  60 . 
     An air outlet of the fan  7  is connected to one end of the burner head  60  to supply the air required to combust the fuel in the combustion device  6 . 
       FIG. 5  is a side view illustrating the burner head  60  of the combustion device  6 .  FIG. 6  is a front view illustrating the burner head  60 ,  FIG. 7  is a rear view illustrating the burner head  60 , and  FIG. 8  is a plan view illustrating the burner head  60 . 
     As illustrated in  FIGS. 5 to 8 , the burner head  60  includes a tubular body  61 , voids  62 , an ignition device  63 , a mixer  64 , a nozzle  65 , a heat insulator  66 , a swirl flow generator  67 , an impeller  68 , and a flame rod  69 . 
     The tubular body  61  is made of, for example, heat-resistant metal. The tubular body  61  having a pillar shape is constituted by basal planes which are a base  612  provided at one end (first end) in the nozzle  65  side and the heat insulator  66  at the other end (second end) opposite to the nozzle  65  side; and a side surface connecting to the basal planes. The interior of the tubular body  61  forms space enclosed by the basal planes and the side surface. The basal planes of the tubular body  61  are approximately parallel to the radiation plane of the radiator  2 . The side surface of the tubular body  61  is approximately perpendicular to the radiation plane of the radiator  2 . Here, the side surface of the tubular body  61  is not necessarily be approximately perpendicular to the radiation plane of the radiator  2  as long as the side surface of the tubular body  61  has a predetermined angle with respect to the radiation plane so as to be able to spread the flame on the radiation plane of the radiator  2 . 
     The voids  62  are formed on the side surface of the tubular body  61 . As illustrated in  FIG. 5 , the voids  62  are microscopic round holes evenly formed in a range from the center of the side surface of the tubular body  61  to the second end of the tubular body  61  near the heat insulator  66 . The shape of the voids  62  may not be limited to circle as illustrated in  FIG. 5 , but may be, for example, square, or a slit-like pore. In addition, the size of the voids  62 , and the interval between the voids  62  may not be even. Moreover, the voids  62  may not be necessarily perforated on the side surface of the tubular body  61  made of a metal plate as illustrated in  FIG. 5 , but may be realized by forming the side surface of the tubular body  61  by a material having microscopic apertures such as metal knit or a sintered article. 
     The ignition device  63  is provided outside the tubular body  61 , for example, along the side surface of the tubular body  61 . For example, the ignition device  63  is provided on the base  612  located in the first end side of the tubular body  61 . The ignition device  63  is, for example, an ignition plug with an electrode to generate an electric spark. 
     The mixer  64  is a hollow pillar body connecting the tubular body  61  to the fan  7  to allow communication between the tubular body  61  and the fan  7 . The mixer  64  allows the air from the fun  7  to flow into the space of the tubular body  61 . As illustrated in  FIG. 8 , the mixer  64  is provided with the nozzle  65 . In addition, as illustrated in  FIG. 5 , the mixer  64  is provided with an overheat protector  641  to detect a flame when the fuel in the tubular body  61  or the mixer  64  ignites and catches fire. 
     The nozzle  65  is provided in the mixer  64 . The nozzle  65  is inserted into the mixer  64  from the side surface of the mixer  64 . Holes are formed in the nozzle  65  to inject the fuel into the mixer  64 . With the present embodiment, propane gas is used as the fuel as described above, and therefore the shape of the nozzle  65  is suitable to inject the propane gas. When another type of fuel, for example, kerosene is used, it is preferred that the shape of the nozzle  65  is suitable to inject the kerosene. 
     The heat insulator  66  is provided on the basal plane of the tubular body  61  in the second end side. As illustrated in  FIG. 3 , the heat insulator  66  is provided in the combustion space  22  to face the inner surface of the radiator  2 . The heat insulator  66  is made of a material with high heat insulating properties, for example, rock wool, alumina fibers or a ceramic. The heat insulator  66  insulates between the tubular body  61  and the radiator  2  to prevent the heat from the radiator  2  from transferring to the tubular body  61 . 
     The swirl flow generator  67  is made of, for example, a metal plate material. For example, the swirl flow generator  67  is provided on the mixer  64  near the fan  7 , to be more specific, provided in an airflow path closer to the fan  7  than the nozzle  65 . The swirl flow generator  67  has the impeller  68  provided in the airflow path to generate a swirl flow in the air-fuel mixture flowing through the tubular body  61 . 
     As illustrated in  FIG. 7 , the swirl flow generator  67  as a plate is cut into an approximate rectangle, leaving uncut four corners, and each side of the rectangle separated from the swirl flow generator  67  is cut at an approximate middle point to form four approximate rectangular blades. Then, the separated portions are turned to form the impeller  68 . Here, in the swirl flow generator  67 , the corners of the four rectangular blades at the center of the impeller  68  are not separated from each other. The air flows through the gap created between each of the four corners of the impeller  68  which are not separated from the swirl flow generator  67  and the center of the swirl flow generator  67  where the four rectangular blades are not separated from each other. 
     The number of blades, the shape of the impeller  68 , and the shape of the airflow path may not be limited to the present embodiment as long as the swirl flow generator  67  and the impeller  68  can generate a swirl flow in the air-fuel mixture flowing through the tubular body  61 . In addition, the impeller  68  is not limited to the fixed type impeller made of a plate material as described in the present embodiment, but may be, for example, rotor blades rotating about a rotating shaft. Moreover, the impeller  68  is not necessarily located between the fan  7  and the nozzle  65  in the airflow path as the present embodiment. For example, the impeller  68  may be disposed in the airflow path behind the nozzle  65 . 
     The flame rod  69  is provided outside the tubular body  61 , for example, along the side surface of the tubular body  61 . For example, the flame rod  69  is provided on the base  612  to which the first end of the tubular body  61  is attached. The flame rod  69  is made of a steel material with heat resistance. The flame rod  69  detects the presence or absence of a flame, based on a change in current flowing through the steel material. 
       FIG. 9  is a side cross-sectional view illustrating the burner head  60 . As illustrated in  FIG. 9 , mesh  613  is provided in the tubular body  61  of the burner head  60  along the inner wall of the tubular body  61 . For example, the mesh  613  is metal mesh with heat resistance, and is configured to prevent a flame from entering the tubular body  61  from the voids  62 . In addition, the mesh  613  can prevent exterior dirt from entering the combustion device  6 . Moreover, the mesh  613  can control an appropriate amount of air-fuel mixture exiting the tubular body  61  from the voids  62 . 
     &lt;Operation of Infrared Radiation Heater&gt; 
     Next, the operation of the infrared radiation heater  1  will be described. In the infrared radiation heater  1 , the gas supplied from the gas pipe connector  8  is jetted from the nozzle  65 , and air is supplied from the fan  7  to the mixer  64 . A swirl flow is formed in the air supplied from the fan  7  by the impeller  68  of the swirl flow generator  67  to mix the air with the gas from the nozzle  65  well, so that air-fuel mixture is generated. Therefore, the infrared radiation heater  1  can restrain the unevenness of the flame, so that it is possible to restrain the unevenness of the heat transferring to the radiator  2 . 
     The air-fuel mixture made in the mixer  64  flows into the tubular body  61  from the first end of the tubular body  61 . The air-fuel mixture supplied into the tubular body  61  is spread in a predetermined direction along the radiation plane of the radiator  2 , via the plurality of microscopic voids  62  formed on the side surface of the tubular body  61 , and then is released to the outside of the tubular body  61 , that is, released into the combustion space  22  of the combustion chamber  21 . 
     The air-fuel mixture released into the combustion space  22  is ignited by a spark generated by the ignition device  63  provided outside the tubular body  61 . Ignited air-fuel mixture spreads and burns in a direction with a predetermined angle, for example, a direction along the radiation plane of the radiator  2  to form a flame. 
     The mesh  613  provided in the tubular body  61  and the voids  62  prevent the flame from entering the tubular body  61 . Therefore, the infrared radiation heater  1  can prevent the gas from burning in the tubular body  61  with the flame entering the tubular body  61 , that is, prevent so-called “backfire.” 
     The whole radiator  2  is evenly heated by the flame spreading in the direction along the radiation plane of the radiator  2  and turns red. Infrared radiation is emitted from the whole radiation plane of the radiator  2  to the outside. 
     Effect of Embodiment 
     In the infrared radiation heater  1  according to the present embodiment, the air-fuel mixture enters the tubular body  61  from the first end of the tubular body  61  located in the nozzle  65  side. In the infrared radiation heater  1 , the side surface of the tubular body  61  faces the direction with a predetermined angle with respect to the radiation plane of the radiator  2 . In addition, in the infrared radiation heater  1 , the air-fuel mixture is released into the combustion chamber  21  from the plurality of microscopic voids  62  formed on the side surface of the tubular body  61 . Therefore, the infrared radiation heater  1  can generate a flame in the direction along the radiation plane of the radiator  2 . Consequently, it is possible to evenly heat the whole radiation plane of the radiator  2  to improve the infrared radiation efficiency. In addition, the infrared radiation heater  1  can prevent the flame from returning to the inside of the tubular body  61  by the plurality of microscopic voids  62 . 
     The infrared radiation heater  1  includes the heat insulator  66  disposed in the second end of the tubular body  61  of the combustion device  6  to insulate between the tubular body  61  and the radiator  2 . Therefore, the infrared radiation heater  1  can prevent the heat emitted from the radiator  2  from transferring to the tubular body  61 , and consequently it is possible to prevent the air-fuel mixture in the tubular body  61  from being heated, and therefore prevent the backfire. In addition, the infrared radiation heater  1  includes the heat insulator  66 , and therefore it is possible to prevent deterioration of the front end of the tubular body  61  due to the heat from the radiator  2 . 
     In the infrared radiation heater  1 , the impeller  68  is provided in the airflow to generate a swirl flow in the air-fuel mixture flowing through the tubular body  61 . By this means, the infrared radiation heater  1  can mix the gas with the air well to make the air-fuel mixture, and therefore it is possible to improve the combustion state of the gas. 
     The infrared radiation heater  1  includes the fixed type impeller  68  made of a plate material, and therefore it is possible to improve the combustion state of the gas without any movable part. 
     The infrared radiation heater  1  includes the voids  62  formed on a side surface of the tubular body  61  in the circumferential direction, and therefore it is possible to generate a flame in the direction along the radiation plane of the radiator  2 , and consequently to evenly heat the whole radiation plane of the radiator  2 . 
     The infrared radiation heater  1  includes the mesh  613  formed in the tubular body  61 , which is provided for the voids  62 . Consequently, it is possible to prevent the flame from returning to the inside of the tubular body  61 . Moreover, the mesh  613  can prevent exterior dirt from entering the combustion device  6  which causes a malfunction of the infrared radiation heater  1 . 
     The infrared radiation heater  1  according to the present embodiment is applicable to a heater configured to combust fuel other than the above-described propane gas and kerosene, for example, natural gas. 
     REFERENCE SIGNS LIST 
     
         
           1  infrared radiation heater 
           2  radiator 
           3  louver 
           4  casing 
           5  frame 
           6  combustion device 
           7  fan 
           8  gas pipe connector 
           21  combustion chamber 
           22  combustion space 
           51  side surface support 
           53  wheel 
           60  burner head 
           61  tubular body 
           62  void 
           63  ignition device 
           64  mixer 
           65  nozzle 
           66  heat insulator 
           67  swirl flow generator 
           68  impeller 
           69  flame rod 
           612  base 
           613  mesh 
           641  overheat protector