Patent Publication Number: US-9410699-B2

Title: Combustion heater

Description:
Priority is claimed on Japanese Patent Application No. 2011-163867, filed Jul. 27, 2011, the content of which is incorporated herein by reference. 
     This application is a Continuation of International Application No. PCT/JP2012/068826, filed on Jul. 25, 2012, claiming priority based on Japanese Patent Application No. 2011-163867, filed Jul. 27, 2011, the content of which is incorporated herein by reference in their entity. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a combustion heater that heats an object to be fired by burning fuel. 
     BACKGROUND ART 
     Gas heaters that heat a radiating body with combustion heat produced by the burning of fuel gas and that heat industrial materials and food and the like with radiating heat from the radiation surface of a radiating body are widely gaining popularity. 
     Also, technology has been proposed that increases the thermal efficiency by preheating the fuel gas prior to combustion with the heat of exhaust gas (For example, Patent Document 1). In Patent Document 1, a constitution is disclosed that is provided with a combustion chamber that comes into contact with the outer wall that is disposed around the outer circumference of the main body, a lead-in portion that guides fuel gas from the center of the main body to the combustion chamber, and a lead-out portion that concentrates post-combustion exhaust gas at the center of the main body and guides it to outside the body, with the lead-in portion and the lead-out portion made adjacent to each other by having a partitioning plate serve as a boundary. 
     PRIOR ART DOCUMENT 
     Patent Document 
     
         
         [PATENT DOCUMENT 1] Japanese Patent No. 4494346 
       
    
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     For example, in the combustion heater such as that of the constitution of Patent Document 1 given above, in the combustion chamber, by causing the fuel gas that flows in from the lead-in portion to collide with the outer wall and to be retained, the flame is stabilized. In this case, the combustion chamber must be brought close to the outer wall. 
     Also, for example, if the combustion chamber can be spaced apart from the outer wall, it is possible to inhibit heat dissipation from the combustion chamber to outside the combustion heater via the outer wall, and so it is possible to expect a further improvement in the thermal efficiency. 
     In this way, if the degree of freedom in the arrangement of the combustion chamber increases, since the possibility of a further increase in efficiency broadens, an improvement in the design freedom is sought in the arrangement of the combustion chamber of the combustion heater. 
     The present invention has as its object to provide a combustion heater that enables an increase in the freedom of arrangement of the combustion chamber. 
     Means for Solving the Problems 
     The combustion heater according to the first aspect of the present invention is provided with a heating plate; a placement plate disposed opposite the heating plate; an outer wall provided around the outer circumference of the heating plate and the placement plate; a partitioning plate disposed so as to face the heating plate and the placement plate inside a space enclosed by the heating plate, the placement plate, and the outer wall, that forms a lead-in portion by a gap with the placement plate, and that forms a lead-out portion by a gap with the heating plate; a linking portion that links the lead-in portion and the lead-out portion; a combustion chamber that combusts fuel gas at the lead-out portion near the linking portion; and a flame-stabilization portion that is provided in the combustion chamber and that maintains the combustion of the fuel gas in the combustion chamber. 
     In the combustion heater according to the second aspect of the present invention, the linking portion in the aforementioned first aspect may be one or a plurality of through-holes provided in the partitioning plate. 
     In the combustion heater according to the third aspect of the present invention, the flame-stabilization portion in the aforementioned first aspect or second aspect may include a concavity that is provided at a position of the heating plate opposite the linking portion. 
     In the combustion heater according to the fourth aspect of the present invention, the flame-stabilization portion in any one of the aforementioned first to third aspects may include a catalyst. 
     In the combustion heater according to the fifth aspect of the present invention, the flame-stabilization portion in any one of the aforementioned first to fourth aspects may include a porous body. 
     Effects of the Invention 
     According to the present invention, increasing the degree of freedom of arrangement of the combustion chamber becomes possible. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view that shows an example of the external appearance of the combustion heating system in the first embodiment of the present invention. 
         FIG. 2  is a drawing for describing the structure of the combustion heating system in the first embodiment of the present invention. 
         FIG. 3  is a cross-sectional view along the line of  FIG. 1 . 
         FIG. 4A  is a drawing for describing the linking portion and the flame-stabilization portion. 
         FIG. 4B  is a drawing for describing the linking portion and the flame-stabilization portion. 
         FIG. 5  is a partially enlarged view of  FIG. 3 . 
         FIG. 6  is a drawing for describing a combustion heater in the second embodiment. 
         FIG. 7  is a drawing for describing a combustion heater in the third embodiment of the present invention. 
         FIG. 8  is a drawing for describing a combustion heater in the fourth embodiment of the present invention. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Hereinbelow, the preferred embodiments of the present invention shall be described with reference to the appended drawings. Note that in the following drawings, the scale of each member shall be suitably changed in order to make each member a recognizable size. Also, in the description and the drawings, by giving the same reference numerals to those elements having essentially the same function and constitution, overlapping explanations shall be omitted, and the illustration of elements with no direct connection to the present invention shall be omitted. 
     First Embodiment 
     Combustion Heating System  100   
       FIG. 1  is a perspective view that shows an external appearance of the combustion heating system  100  in the first embodiment. The combustion heating system  100  in the first embodiment is a premixed-type in which town gas or the like and air that serves as the oxidant gas for combustion are mixed prior to being supplied to the body container. However, the combustion heating system  100  is not limited to a certain case, and may also be a diffusion-type that performs so-called diffusion combustion. 
     As shown in  FIG. 1 , in the combustion heating system  100 , a plurality (two in  FIG. 1 ) of combustion heaters  110  are arranged side by side and connected, and upon receiving a supply of a mixed gas (hereinbelow called “fuel gas”) consisting of town gas or the like and air, the fuel gas combusts at the respective combustion heaters  110 , whereby they are heated. In the combustion heating system  100 , the exhaust gas that is produced by that combustion is collected. 
       FIG. 2  is a drawing for describing the structure of the combustion heating system  100  in the first embodiment of the present invention. As shown in  FIG. 2 , the combustion heating system  100  is provided with a placement plate  120 , an outer wall  122 , a partitioning plate  124 , and a heating plate  126 . 
     The placement plate  120  is a plate-shaped member that is formed by a material with high thermal resistance and oxidation resistance, for example, stainless steel (SUS: Stainless Used Steel) or a material with low thermal conductivity. 
     The outer wall  122  is constituted by a thin plate-shaped member that has an outer shape in which the outer circumferential surface thereof is flush with the outer circumferential surface of the placement plate  120 , and is laminated on the placement plate  120  as illustrated. In this outer wall  122 , two holes  122   a  (through-holes) that penetrate in the thickness direction (the lamination direction of the outer wall  122  and the placement plate  120 ) and whose inner circumference has a track shape (a shape consisting of two approximately parallel linear portions and two curves (semicircles) that connect the end portions of the two linear portions) are provided. 
     Similarly to the placement plate  120 , the partitioning plate  124  is formed by a material with high thermal resistance and oxidation resistance, for example, stainless steel, or a material with high thermal conductivity, such as brass or the like. The partitioning plate  124  is a thin plate-shaped member that has an outer shape that fits in the inner circumferential surface of the hole  122   a  of the outer wall  122 . Accordingly, the partitioning plate  124  is arranged in an approximately parallel manner with the placement plate  120  on the inner side of the outer wall  122  by being fitted in the hole  122   a  of the outer wall  122 . 
     The heating plate  126 , similarly to the placement plate  120 , is a thin plate-shaped member that is formed by a material with high thermal resistance and oxidation resistance, for example, stainless steel, or a material with high thermal conductivity, such as brass or the like. 
     The heating plate  126  has an outer shape such that the outer circumferential surface thereof and the outer circumferential surface of the placement plate  120  and the outer wall  122  become flush, and is laminated on the outer wall  122  and the partitioning plates  124 . At this time, the heating plate  126  and the placement plate  120  are oppositely arranged in a substantially mutually parallel manner (virtually parallel in order to cause super-enthalpy combustion in the present embodiment). Also, the outer wall  122  is disposed following the outer circumference of the heating plate  126  and the placement plate  120 , and the partitioning plates  124  are disposed opposite the heating plate  126  and the placement plate  120  inside the space enclosed by the heating plate  126 , the placement plate  120 , and the outer wall  122 . 
     If gaps are formed between the placement plate  120 , the partitioning plates  124  and the heating plate  126 , they may be oppositely arranged in an inclined manner. Also, there is no restriction on the thickness of the placement plate  120 , the partitioning plates  124  and the heating plate  126 , and moreover they are not limited to flat plates, and may also be formed so that the thickness varies. 
     In this way, the body container of the combustion heating system  100  is constituted by blocking the top and bottom of the outer wall  122  with the heating plate  126  and the placement plate  120 . Moreover, the combined surface area of the top and bottom wall surfaces (the outer surfaces of the heating plate  126  and the placement plate  120 ) is greater than the surface area of the outer surface of the outer wall  122 . That is to say, the top and bottom wall surfaces occupy the majority of the outer surface of the body container. 
     Also, the combustion heating system  100  is constituted by connecting two combustion heaters  110  that are arranged side by side, and at the connection region between both combustion heaters  110 , a flame transfer portion  128  that is continuous with a sealed space in the connected combustion heaters  110  is formed. However, although referred to as a sealed space, when used in a gas, it is not always necessary to completely seal it. In the combustion heating system  100  of the present embodiment, due to a single ignition by an ignition device such as an igniter (not illustrated), a flame spreads to the combustion heaters  110  that are connected through the flame transfer portion  128  and is ignited. As described above, two combustion heaters  110  are provided in the combustion heating system  100 , but since the two combustion heaters  110  have the same constitution, hereinbelow one combustion heater  110  shall be described. 
       FIG. 3  is a cross-sectional view along the line of  FIG. 1 . As shown in  FIG. 3 , in the placement plate  120 , a in-flow hole  132  that penetrates in the thickness direction is provided at the center portion of the combustion heater  110 . A first pipe portion  130  through which fuel gas flows is connected to this in-flow hole  132 , and fuel gas is guided into the body container of the combustion heater  110  via the in-flow hole  132 . 
     Within the body container, a lead-in portion  134  and a lead-out portion  142  are adjacently formed by being partitioned by the partitioning plate  124 . The positional relation of the partitioning plate  124 , the lead-in portion  134 , and the lead-out portion  142  shall be described below. 
     The lead-in portion  134  is formed by the gap between the placement plate  120  and the partitioning plate  124 , and guides the fuel gas that has flowed in from the in-flow hole  132  in a radial manner to a combustion chamber  138 . 
     A linking portion  136  is one or a plurality of through-holes provided in the partitioning plate  124  in the present embodiment. The linking portion  136  links the lead-in portion  134  and the lead-out portion  142 . 
     The combustion chamber  138  is arranged in a space that is enclosed by the placement plate  120 , the heating plate  126 , and the outer wall  122 . Also, the combustion chamber  138  is arranged on the lead-out portion  142  in the vicinity of the linking portion  136 . The ignition device (not illustrated) is provided at an arbitrary position of the combustion chamber  138 . Also, in the combustion chamber  138 , fuel gas that is introduced from the lead-in portion  134  combusts, and the exhaust gas that is produced by this combustion is led out toward the lead-out portion  142 . 
     A flame-stabilization portion  140  is provided in the combustion chamber  138 , and maintains the combustion of the fuel gas in the combustion chamber  138 . In the present embodiment, the flame-stabilization portion  140  is a concavity that is provided at a position in the heating plate  126  facing the linking portion  136 . 
       FIG. 4A  and  FIG. 4B  are drawings for describing the linking portion  136  and the flame-stabilization portion  140 .  FIG. 4A  and  FIG. 4B  show front views of the heating plate  126  and the partitioning plate  124 , with the respective opposing surfaces of the heating plate  126  and the partitioning plate  124  facing the front. The flame-stabilization portion  140  that is a concavity (shown by the hatching) provided in the heating plate  126  is for example formed in a track shape that resembles the outer shape of the partitioning plate  124  as shown in  FIG. 4A . Also, the linking portions  136  are also disposed in a track shape (in  FIG. 4A , virtual lines that connect the centers of the linking portions  136  are shown by broken lines) so as to face the flame-stabilization portions  140 . 
     Moreover, the positions at which the linking portions  136  are disposed are not limited to a track shape, and as shown in  FIG. 4B , they may also be arranged so as to form a row in the partitioning plate  124 . In this case, the flame-stabilization portion  140  may be a plurality of circular concavities that are provided at positions facing the linking portions  136 . Also, the linking portions  136  and the flame-stabilization portions  140  may be disposed in concentric circles, or at arbitrary positions. 
     Also, as shown in  FIG. 3 , the lead-out portion  142  is formed by a gap between the heating plate  126  and the partitioning plate  124 , and gathers the exhaust gas that is produced by the combustion in the combustion chamber  138  at the center portion of the combustion heater  110 . 
     As described above, in the body container, since the lead-in portion  134  and the lead-out portion  142  are adjacently formed, it is possible to transfer the heat of the exhaust gas to the fuel gas through the partitioning plate  124 , and thereby preheat the fuel gas. 
     A radiation surface  144  is a surface on the external side of the heating plate  126 , and is heated by the exhaust gas that flows through the lead-out portion  142  and the combustion in the combustion chamber  138 , and transmits the radiation heat to an object to be fired. 
     An exhaust hole  146  that penetrates the center of the combustion heater  110  in the thickness direction is provided in the partitioning plate  124 . A second pipe portion  148  is fitted in the inner circumferential portion of this exhaust hole  146 . The exhaust gas, after heating the radiation surface  144 , is lead out to the outside of the combustion heater  110  via the exhaust hole  146 . 
     The second pipe portion  148  is arranged inside of the first pipe portion  130 . That is to say, the first pipe portion  130  and the second pipe portion  148  form a double pipe. Also, the second pipe portion  148  has a function of transmitting the heat of the exhaust gas to the fuel gas that flows through the first pipe portion  130 . 
     Here, the region (edge portion) of the placement plate  120  where the in-flow hole  132  is formed is fixed to the end portion of the first pipe portion  130 , and the exhaust hole  146  of the partitioning plate  124  is fixed to the distal end of the second pipe portion  148  that protrudes out farther than the first pipe portion  130 , and the placement plate  120  and the partitioning plate  124  are separated by the difference between the distal end of the first pipe portion  130  and the distal end of the second pipe portion  148 . 
     Note that in the present embodiment, the in-flow hole  132  is provided in the placement plate  120 , and the exhaust hole  146  is provided in the partitioning plate  124 , but the in-flow hole  132  may be provided in the partitioning plate  124 , and the exhaust hole  146  may be provided in the heating plate  126 . In this case, the first pipe portion  130  and the second pipe portion  148  are inserted from the heating plate  126  into the lead-in portion  134  and the lead-out portion  142 , and the first pipe portion  130  may be arranged within the second pipe portion  148 . Also, the first pipe portion  130  and the second pipe portion  148  may be individually provided, and in this case, the in-flow hole  132  may be arranged at either the placement plate  120  or the partitioning plate  124 , and the exhaust hole  146  may be arranged at either the heating plate  126  or the partitioning plate  124 . 
     Next, the flow of the fuel gas and the exhaust gas shall be described in concrete terms.  FIG. 5  is a partially enlarged view of  FIG. 3 .  FIG. 5  shows a partial enlargement of the left side of  FIG. 3 . In  FIG. 5 , the outlined arrows show the flow of the fuel gas, the arrows filled in with gray show the flow of the exhaust gas, and the arrows filled in with black show the movement of heat. When the fuel gas is introduced to the first pipe portion  130 , the fuel gas flows in from the in-flow hole  132  to the lead-in portion  134 , and flows toward the linking portions  136  while spreading out in a radial pattern in the horizontal direction. Then, the fuel gas, by passing through the linking portions  136 , collides with the flame-stabilization portion  140  of the combustion chamber  138 , and the flow rate decreases (is retained). 
     The fuel gas, after combustion by the flame that is ignited in the combustion chamber  138 , becomes high-temperature exhaust gas, and the exhaust gas, after transmitting its heat to the radiation surface  144  of the heating plate  126  byin-flowg through the lead-out portion  142 , passes through the exhaust hole  146  to be led out from the second pipe portion  148  to the outside. 
     The partitioning plate  124  is formed by a material that conducts heat comparatively easily, and the heat of the exhaust gas that passes through the lead-out portion  142  is conveyed to the fuel gas that passes through the lead-in portion  134  via the partitioning plate  124 . That is to say, the exhaust gas that flows through the lead-out portion  142  and the fuel gas that flows through the lead-in portion  134  become counter flows sandwiching the partitioning plate  124 . Accordingly, it becomes possible to effectively preheat the fuel gas with the heat of the exhaust gas, and it is possible to obtain a high thermal efficiency. Due to the so-called super-enthalpy combustion that combusts the fuel gas after preheating it in this way, it is possible to stabilize the combustion of fuel gas, and suppress to an extremely low concentration the concentration of CO (carbon monoxide) that is generated by incomplete combustion. 
     Also, the combustion heater  110  of the present embodiment is provided with the flame-stabilization portion  140  that consists of a concavity in the heating plate  126 , and when the fuel gas is made to collide with this concavity, the fuel gas is hindered from diffusing compared to the case of colliding with a flat surface. Accordingly, it is possible to generate retention in the fuel gas, and so stabilizing the flame becomes possible. Accordingly, even if the combustion chamber  138  is provided offset from the outer wall  122 , it is possible to stabilize the flame, and the degree of freedom of placement of the combustion chamber  138 , that is to say, the degree of freedom of the design of the combustion heater  110 , is high. Then, as in the present embodiment, if the position of the linking portion  136  and the combustion chamber  138  are moved away from the outer wall  122 , heat dissipation from the outer wall  122  is suppressed, and so it is possible to raise the thermal efficiency. 
     Also, according to the combustion heater  110  of the present embodiment, since it is possible to perform flame stabilization with the simple constitution of providing a concavity in the heating plate  126 , there is no requirement for a particular manufacturing cost for the sake of flame stabilization. Moreover, the combustion heater  110  is able to absorb thermal expansion with the concavity, and the radiation surface area increases. Accordingly, the contact surface area with the exhaust gas increases, the efficiency of heat transfer from the exhaust gas to the heating plate  126  improves, and it is possible to raise the radiant efficiency. 
     Also, by making the linking portions  136  of the combustion heater  110  be through-holes, it is possible to create the linking portions  136  with the simple process of punching holes in the partitioning plate  124 , and so it is possible to lower the manufacturing cost. Moreover, by adopting a constitution that provides a plurality of the linking portions  136 , a plurality of the flames that heat the radiation surface  144  are formed. For that reason, the combustion heater  110  can make the heating of the radiation surface  144  uniform. 
     Second Embodiment 
     Next, a flame-stabilization portion  240  in a second embodiment shall be described. In the second embodiment, since the flame-stabilization portion  240  differs from that of the aforementioned first embodiment, here descriptions of the constitutions that are the same as the aforementioned first embodiment shall be omitted, and only the flame-stabilization portion  240  with the differing constitution shall be described. 
       FIG. 6  is a drawing for describing a combustion heater  210  in the second embodiment. As shown in  FIG. 6 , the flame-stabilization portion  240  of the present embodiment is constituted by including a catalyst such as platinum or vanadium. In this way, with a constitution that disposes a catalyst in the combustion chamber  138 , combustion in the combustion heater  210  stabilizes, and it is possible to expand the density and temperature range of the fuel gas that can be combusted. 
     Also, in the present embodiment, it is possible to realize the same operation and effect as the abovementioned first embodiment. That is to say, the combustion heater  210  is provided with the flame-stabilization portion  240 , and the degree of freedom of placement of the combustion chamber  138  is high. For that reason, for example, it is possible to arrange the positions of the linking portions  136  and the combustion chamber  138  spaced apart from the outer wall  122 , and it is possible to inhibit heat dissipation from the outer wall  122 , and thereby raise the thermal efficiency. 
     Third Embodiment 
     Next, a flame-stabilization portion  340  in the third embodiment shall be described. In the third embodiment, since the flame-stabilization portion  340  differs from that of the aforementioned first embodiment, here descriptions of the constitutions that are the same as the aforementioned first embodiment shall be omitted, and only the flame-stabilization portion  340  with the differing constitution shall be described. 
       FIG. 7  is a drawing for describing a combustion heater  310  in the third embodiment. As shown in  FIG. 7 , the flame-stabilization portion  340  of the present embodiment is constituted by including a porous body. The porous body consists of a combination of, for example, metal knit, sintered metal, ceramic, wire netting, punching metal, corrugated plate or the like. With a constitution that disposes the porous body in the combustion chamber  138 , the flame stability of the combustion heater  110  increases, and so the combustion stabilizes. 
     Also, in the present embodiment, it is possible to realize the same operation and effect as the aforementioned first embodiment. 
     Fourth Embodiment 
     Next, a linking portion  436  in the fourth embodiment shall be described. In the fourth embodiment, since the linking portion  436  differs from that of the aforementioned first embodiment, descriptions of the constitutions that are the same as the aforementioned first embodiment shall be omitted here, and only the linking portion  436  with the differing constitution shall be described. 
       FIG. 8  is a drawing for describing the combustion heater  410  in the fourth embodiment. As shown in  FIG. 8 , in the present embodiment, a gap is provided between the partitioning plate  124  and the outer wall  122 , and is made to serve as the linking portion  436 . In this case, by providing a catalyst or by providing a porous body as the flame-stabilization portion  240  in the manner of the present embodiment, it is possible to move the arrangement of the combustion chamber  138  away from the outer wall  122 , and toward the exhaust hole  146 . In this case, since backfiring is inhibited by the flame-stabilization portion  240 , there is no need for a constitution such as a throttle for backfire prevention. 
     Also, for example a projection portion that narrows the flow passage of the lead-out portion  142  may be provided at the outer wall  122  side of the partitioning plate  124 , beyond combustion chamber  138 . With this constitution, retention occurs on the combustion chamber  138  side of the projection portion due to the fuel gas going around the projection portion and the flame stability further increases. 
     Also, in the present embodiment, it is possible to realize the same operation and effect as the aforementioned first embodiment. 
     Hereinabove, preferred embodiments of the present invention were described while referring to the attached drawings, but it goes without saying that the present invention is not limited to the embodiments. It is clear that a person skilled in the art could conceive various modifications and amendments within the scope disclosed in the claims, and they are understood to naturally belong to the technical scope of the present invention. 
     For example, in the aforementioned embodiments, the descriptions were given for the case of constituting the flame-stabilization portions with any of a concavity, a porous body, and a catalyst, but the flame-stabilization portions may also include a plurality among a concavity, a porous body, and a catalyst. Also, the constitution of the flame-stabilization portion is not limited to a concavity, a porous body, and a catalyst. In any case, the flame-stabilization portion should be a constitution that enables flame-stabilization by causing the flow of fuel gas in the combustion chamber to stagnate. 
     Also, in the aforementioned embodiments, the combustion heating system  100  in which two combustion heaters  110  are provided side by side was given as an example, but the combustion heater  110  may also be used alone without the combustion heating system  100 . 
     INDUSTRIAL APPLICABILITY 
     The present invention can be utilized in a combustion heater that heats an object to be fired by burning fuel. 
     DESCRIPTION OF THE REFERENCE NUMERALS 
     
         
         
           
               110 : combustion heater 
               120 : placement plate 
               122 : outer wall 
               124 : partitioning plate 
               126 : heating plate 
               134 : lead-in portion 
               136 ,  436 : linking portion 
               138 : combustion chamber 
               140 ,  240 ,  340 : flame-stabilization portion 
               142 : lead-out portion