Combustion heater

A combustion heater (110) that is provided with a heating plate (126); a placement plate (120) disposed opposite the heating plate; an outer wall (122) provided around the outer circumference of the heating plate and the placement plate; a partitioning plate (124) that is disposed opposite 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 (134) by a gap with the placement plate, and that forms a lead-out portion (142) by a gap with the heating plate; a linking portion (136) that links the lead-in portion and the lead-out portion; a combustion chamber (138) that combusts fuel gas at the lead-out portion near the linking portion; and a flame-stabilization portion (140) that is provided in the combustion chamber and that maintains the combustion of the fuel gas in the combustion chamber.

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

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.

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

FIG. 1is a perspective view that shows an external appearance of the combustion heating system100in the first embodiment. The combustion heating system100in 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 system100is not limited to a certain case, and may also be a diffusion-type that performs so-called diffusion combustion.

As shown inFIG. 1, in the combustion heating system100, a plurality (two inFIG. 1) of combustion heaters110are 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 heaters110, whereby they are heated. In the combustion heating system100, the exhaust gas that is produced by that combustion is collected.

FIG. 2is a drawing for describing the structure of the combustion heating system100in the first embodiment of the present invention. As shown inFIG. 2, the combustion heating system100is provided with a placement plate120, an outer wall122, a partitioning plate124, and a heating plate126.

The placement plate120is 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 wall122is 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 plate120, and is laminated on the placement plate120as illustrated. In this outer wall122, two holes122a(through-holes) that penetrate in the thickness direction (the lamination direction of the outer wall122and the placement plate120) 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 plate120, the partitioning plate124is 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 plate124is a thin plate-shaped member that has an outer shape that fits in the inner circumferential surface of the hole122aof the outer wall122. Accordingly, the partitioning plate124is arranged in an approximately parallel manner with the placement plate120on the inner side of the outer wall122by being fitted in the hole122aof the outer wall122.

The heating plate126, similarly to the placement plate120, 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 plate126has an outer shape such that the outer circumferential surface thereof and the outer circumferential surface of the placement plate120and the outer wall122become flush, and is laminated on the outer wall122and the partitioning plates124. At this time, the heating plate126and the placement plate120are oppositely arranged in a substantially mutually parallel manner (virtually parallel in order to cause super-enthalpy combustion in the present embodiment). Also, the outer wall122is disposed following the outer circumference of the heating plate126and the placement plate120, and the partitioning plates124are disposed opposite the heating plate126and the placement plate120inside the space enclosed by the heating plate126, the placement plate120, and the outer wall122.

If gaps are formed between the placement plate120, the partitioning plates124and the heating plate126, they may be oppositely arranged in an inclined manner. Also, there is no restriction on the thickness of the placement plate120, the partitioning plates124and the heating plate126, 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 system100is constituted by blocking the top and bottom of the outer wall122with the heating plate126and the placement plate120. Moreover, the combined surface area of the top and bottom wall surfaces (the outer surfaces of the heating plate126and the placement plate120) is greater than the surface area of the outer surface of the outer wall122. 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 system100is constituted by connecting two combustion heaters110that are arranged side by side, and at the connection region between both combustion heaters110, a flame transfer portion128that is continuous with a sealed space in the connected combustion heaters110is 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 system100of the present embodiment, due to a single ignition by an ignition device such as an igniter (not illustrated), a flame spreads to the combustion heaters110that are connected through the flame transfer portion128and is ignited. As described above, two combustion heaters110are provided in the combustion heating system100, but since the two combustion heaters110have the same constitution, hereinbelow one combustion heater110shall be described.

FIG. 3is a cross-sectional view along the line ofFIG. 1. As shown inFIG. 3, in the placement plate120, a in-flow hole132that penetrates in the thickness direction is provided at the center portion of the combustion heater110. A first pipe portion130through which fuel gas flows is connected to this in-flow hole132, and fuel gas is guided into the body container of the combustion heater110via the in-flow hole132.

Within the body container, a lead-in portion134and a lead-out portion142are adjacently formed by being partitioned by the partitioning plate124. The positional relation of the partitioning plate124, the lead-in portion134, and the lead-out portion142shall be described below.

The lead-in portion134is formed by the gap between the placement plate120and the partitioning plate124, and guides the fuel gas that has flowed in from the in-flow hole132in a radial manner to a combustion chamber138.

A linking portion136is one or a plurality of through-holes provided in the partitioning plate124in the present embodiment. The linking portion136links the lead-in portion134and the lead-out portion142.

The combustion chamber138is arranged in a space that is enclosed by the placement plate120, the heating plate126, and the outer wall122. Also, the combustion chamber138is arranged on the lead-out portion142in the vicinity of the linking portion136. The ignition device (not illustrated) is provided at an arbitrary position of the combustion chamber138. Also, in the combustion chamber138, fuel gas that is introduced from the lead-in portion134combusts, and the exhaust gas that is produced by this combustion is led out toward the lead-out portion142.

A flame-stabilization portion140is provided in the combustion chamber138, and maintains the combustion of the fuel gas in the combustion chamber138. In the present embodiment, the flame-stabilization portion140is a concavity that is provided at a position in the heating plate126facing the linking portion136.

FIG. 4AandFIG. 4Bare drawings for describing the linking portion136and the flame-stabilization portion140.FIG. 4AandFIG. 4Bshow front views of the heating plate126and the partitioning plate124, with the respective opposing surfaces of the heating plate126and the partitioning plate124facing the front. The flame-stabilization portion140that is a concavity (shown by the hatching) provided in the heating plate126is for example formed in a track shape that resembles the outer shape of the partitioning plate124as shown inFIG. 4A. Also, the linking portions136are also disposed in a track shape (inFIG. 4A, virtual lines that connect the centers of the linking portions136are shown by broken lines) so as to face the flame-stabilization portions140.

Moreover, the positions at which the linking portions136are disposed are not limited to a track shape, and as shown inFIG. 4B, they may also be arranged so as to form a row in the partitioning plate124. In this case, the flame-stabilization portion140may be a plurality of circular concavities that are provided at positions facing the linking portions136. Also, the linking portions136and the flame-stabilization portions140may be disposed in concentric circles, or at arbitrary positions.

Also, as shown inFIG. 3, the lead-out portion142is formed by a gap between the heating plate126and the partitioning plate124, and gathers the exhaust gas that is produced by the combustion in the combustion chamber138at the center portion of the combustion heater110.

As described above, in the body container, since the lead-in portion134and the lead-out portion142are adjacently formed, it is possible to transfer the heat of the exhaust gas to the fuel gas through the partitioning plate124, and thereby preheat the fuel gas.

A radiation surface144is a surface on the external side of the heating plate126, and is heated by the exhaust gas that flows through the lead-out portion142and the combustion in the combustion chamber138, and transmits the radiation heat to an object to be fired.

An exhaust hole146that penetrates the center of the combustion heater110in the thickness direction is provided in the partitioning plate124. A second pipe portion148is fitted in the inner circumferential portion of this exhaust hole146. The exhaust gas, after heating the radiation surface144, is lead out to the outside of the combustion heater110via the exhaust hole146.

The second pipe portion148is arranged inside of the first pipe portion130. That is to say, the first pipe portion130and the second pipe portion148form a double pipe. Also, the second pipe portion148has a function of transmitting the heat of the exhaust gas to the fuel gas that flows through the first pipe portion130.

Here, the region (edge portion) of the placement plate120where the in-flow hole132is formed is fixed to the end portion of the first pipe portion130, and the exhaust hole146of the partitioning plate124is fixed to the distal end of the second pipe portion148that protrudes out farther than the first pipe portion130, and the placement plate120and the partitioning plate124are separated by the difference between the distal end of the first pipe portion130and the distal end of the second pipe portion148.

Note that in the present embodiment, the in-flow hole132is provided in the placement plate120, and the exhaust hole146is provided in the partitioning plate124, but the in-flow hole132may be provided in the partitioning plate124, and the exhaust hole146may be provided in the heating plate126. In this case, the first pipe portion130and the second pipe portion148are inserted from the heating plate126into the lead-in portion134and the lead-out portion142, and the first pipe portion130may be arranged within the second pipe portion148. Also, the first pipe portion130and the second pipe portion148may be individually provided, and in this case, the in-flow hole132may be arranged at either the placement plate120or the partitioning plate124, and the exhaust hole146may be arranged at either the heating plate126or the partitioning plate124.

Next, the flow of the fuel gas and the exhaust gas shall be described in concrete terms.FIG. 5is a partially enlarged view ofFIG. 3.FIG. 5shows a partial enlargement of the left side ofFIG. 3. InFIG. 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 portion130, the fuel gas flows in from the in-flow hole132to the lead-in portion134, and flows toward the linking portions136while spreading out in a radial pattern in the horizontal direction. Then, the fuel gas, by passing through the linking portions136, collides with the flame-stabilization portion140of the combustion chamber138, and the flow rate decreases (is retained).

The fuel gas, after combustion by the flame that is ignited in the combustion chamber138, becomes high-temperature exhaust gas, and the exhaust gas, after transmitting its heat to the radiation surface144of the heating plate126byin-flowg through the lead-out portion142, passes through the exhaust hole146to be led out from the second pipe portion148to the outside.

The partitioning plate124is formed by a material that conducts heat comparatively easily, and the heat of the exhaust gas that passes through the lead-out portion142is conveyed to the fuel gas that passes through the lead-in portion134via the partitioning plate124. That is to say, the exhaust gas that flows through the lead-out portion142and the fuel gas that flows through the lead-in portion134become counter flows sandwiching the partitioning plate124. 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 heater110of the present embodiment is provided with the flame-stabilization portion140that consists of a concavity in the heating plate126, 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 chamber138is provided offset from the outer wall122, it is possible to stabilize the flame, and the degree of freedom of placement of the combustion chamber138, that is to say, the degree of freedom of the design of the combustion heater110, is high. Then, as in the present embodiment, if the position of the linking portion136and the combustion chamber138are moved away from the outer wall122, heat dissipation from the outer wall122is suppressed, and so it is possible to raise the thermal efficiency.

Also, according to the combustion heater110of the present embodiment, since it is possible to perform flame stabilization with the simple constitution of providing a concavity in the heating plate126, there is no requirement for a particular manufacturing cost for the sake of flame stabilization. Moreover, the combustion heater110is 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 plate126improves, and it is possible to raise the radiant efficiency.

Also, by making the linking portions136of the combustion heater110be through-holes, it is possible to create the linking portions136with the simple process of punching holes in the partitioning plate124, and so it is possible to lower the manufacturing cost. Moreover, by adopting a constitution that provides a plurality of the linking portions136, a plurality of the flames that heat the radiation surface144are formed. For that reason, the combustion heater110can make the heating of the radiation surface144uniform.

Second Embodiment

Next, a flame-stabilization portion240in a second embodiment shall be described. In the second embodiment, since the flame-stabilization portion240differs 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 portion240with the differing constitution shall be described.

FIG. 6is a drawing for describing a combustion heater210in the second embodiment. As shown inFIG. 6, the flame-stabilization portion240of 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 chamber138, combustion in the combustion heater210stabilizes, 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 heater210is provided with the flame-stabilization portion240, and the degree of freedom of placement of the combustion chamber138is high. For that reason, for example, it is possible to arrange the positions of the linking portions136and the combustion chamber138spaced apart from the outer wall122, and it is possible to inhibit heat dissipation from the outer wall122, and thereby raise the thermal efficiency.

Third Embodiment

Next, a flame-stabilization portion340in the third embodiment shall be described. In the third embodiment, since the flame-stabilization portion340differs 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 portion340with the differing constitution shall be described.

FIG. 7is a drawing for describing a combustion heater310in the third embodiment. As shown inFIG. 7, the flame-stabilization portion340of 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 chamber138, the flame stability of the combustion heater110increases, 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 portion436in the fourth embodiment shall be described. In the fourth embodiment, since the linking portion436differs 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 portion436with the differing constitution shall be described.

FIG. 8is a drawing for describing the combustion heater410in the fourth embodiment. As shown inFIG. 8, in the present embodiment, a gap is provided between the partitioning plate124and the outer wall122, and is made to serve as the linking portion436. In this case, by providing a catalyst or by providing a porous body as the flame-stabilization portion240in the manner of the present embodiment, it is possible to move the arrangement of the combustion chamber138away from the outer wall122, and toward the exhaust hole146. In this case, since backfiring is inhibited by the flame-stabilization portion240, 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 portion142may be provided at the outer wall122side of the partitioning plate124, beyond combustion chamber138. With this constitution, retention occurs on the combustion chamber138side 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 system100in which two combustion heaters110are provided side by side was given as an example, but the combustion heater110may also be used alone without the combustion heating system100.

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