JP2529473B2 - Heating device - Google Patents

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention can be applied to plate type cookers, warmers, milk heaters, portable water heaters, irons, hair dryers, coffee makers, foot warmers, sesame roasters, sake canisters, etc. The present invention relates to a heat generating device using a heat of combustion as a heat source.

[0002]

2. Description of the Related Art A stove in which fuel gas packed in a liquefied gas cylinder is burned by a burner with flame is widely used and is used for cooking outdoors. Further, such a burner is also used for soldering in piping work. As a portable device that uses catalytic combustion, there is a pocket furnace that uses a platinum catalyst. This is to bring benzine into contact with a catalyst to cause a catalytic reaction, and to put it in clothes to obtain warmth.

[0003]

The equipment using flame combustion that has been conventionally used has a large flame and was suitable for the purpose of directly heating an object with the flame. Since the temperature of the combustion flame is usually 1200 ° C. to 1800 ° C., it was suitable for rapidly heating the object at a high temperature. In spite of these advantages, the flame temperature is high, so that it has a drawback of high fire risk. In order to avoid this danger, it is conceivable to form a combustion chamber in the equipment and burn it in the equipment, but this makes the equipment large and is a problem in practical use.

On the other hand, in the equipment using the conventional catalytic combustion, since the catalyst enables combustion at a low temperature, it is possible to produce a safe equipment. However, when a large amount of combustion is generated, the catalyst becomes too hot and is thermally deteriorated, so that only a device having an extremely small calorific value can be produced.

[0005]

The present invention has the following structure in order to solve such problems. Fuel gas and sky
A mixing part forming an air-fuel mixture, and the flow direction of the mixing part
Metal heating plate installed downstream of the
The passing part of the burned mixture and the flow direction of the passing part
Cerami formed parallel to the flow direction along the inner wall of the flow section
Layered catalyst part in which a platinum group metal catalyst is supported on the carrier.
It is formed on the downstream side in the flow direction of the passage part and the inner surface is
It has an exhaust path that is a part of the plate,
After combustion on the surface of the layered catalyst layer, the exhaust gas is
It is characterized by being cooled.

[0006] Further , as described in claim 2, the exhaust path
The second catalyst body is inserted in the
Supported by a support part of which protrudes from the inner wall surface of the exhaust path
And the second catalyst body and the inner wall surface of the exhaust path are
It is characterized by a structure that faces each other through a space.

[0007]

In the above structure, the reaction in the passage hole is almost completed in the upstream catalyst layer, and the exhaust gas is discharged downstream of the passage hole without the catalyst layer. Here, the reason why a large amount of heat can be generated is that the temperature of the catalyst layer is kept below the heat resistant temperature. When the air-fuel mixture is supplied, the reaction amount of the catalyst layer becomes large and the temperature becomes high. Further, the gas reacts violently upstream of the passage hole, but as it goes downstream, the exhaust gas increases and the fuel concentration decreases, so the reaction gradually ends. When the reaction is completed, the temperature of the exhaust gas is still high. Therefore, after the reaction is completed, the hot plate must receive the heat of the exhaust gas, not the heat of reaction. The downstream side of the passage hole is unnecessary because the catalyst layer hinders heat transfer of exhaust heat. That is, in the upstream where the temperature of the catalyst layer becomes high, the heat plate is heated directly by heat conduction from the catalyst layer, and in the downstream where the reaction is completed, the heat plate is heated by heat transfer between the exhaust gas and the metal wall surface in the passage hole.

Further, when a catalyst body is provided downstream of the passage hole in order to increase the combustion amount, the exhaust gas containing unburned gas that has not been separated by the reaction in the catalyst layer upstream of the passage hole reacts on the surface of the downstream catalyst body. To do. Since the catalyst body is almost separated from the hot plate, it is difficult to cool even in the downstream side, the reaction activation temperature is sufficiently maintained, and the surface becomes hot due to unburned gas. That is, the inner wall surface of the passage hole on the downstream side receives the heat of the exhaust gas on the upstream side by convective heat transfer, while receiving the heat generation of the unburned component as radiation from the high temperature surface of the catalyst body. Therefore, the heat exchange efficiency in the downstream is extremely high, and the apparatus does not become large even with a large combustion amount.

[0009]

1 is a vertical sectional view (a sectional view taken along the line BB 'in FIG. 2) of a heat generating device according to an embodiment of the present invention. FIG. 2 is a horizontal sectional view (sectional view taken along the line AA ′ of FIG. 1). In FIG. 1, reference numeral 1 is a liquefied gas cylinder such as propane or butane. A valve 3 is provided between the cylinder 1 and the nozzle 2. Air is drawn into the mixing chamber 4 by the attraction of the gas flow blown out from the nozzle 2 and mixed uniformly. A hot plate 5 made of aluminum is provided downstream of the mixing chamber 4. The hot plate 5 is provided with five air-fuel mixture passage holes 6. The mixed gas enters the passage holes 6 evenly.

In FIG. 2, a catalyst layer 7 is provided upstream of the passage hole 6.
Are formed. The catalyst layer 7 is formed by adhering a fiber mat of a metal oxide such as alumina and silica with a colloidal metal oxide or water glass, and adhering γ-alumina to the surface of the fiber to increase the surface area. It is formed by supporting a platinum group metal catalyst . In order to increase the adhesive strength, it is also preferable to perform sandblasting or to form a ceramic spray coating on the adhesive surface of aluminum. The thickness of the catalyst layer 7 is in the range of 0.5 mm to 3 mm. Such a catalyst layer 7 is formed upstream of the passage hole 6, but the inner wall of the hot plate 5 is exposed downstream.

A catalyst layer 7 is also formed on the inner wall of the mixing chamber 4, and the catalyst layer 7 is substantially continuous with the catalyst layers 7 of the five passage holes 6. An electric heater 8 heated by a dry cell is provided near the catalyst layer 7 of the mixing chamber 4. The operation state of the present invention in such a configuration will be described below.

[0012] The heater 8 is heated by the dry battery, and the temperature of the catalyst layer 7 which is further adjacent thereto is raised. When the catalyst layer 7 is heated to the catalyst activation temperature of 500 ° C., the valve 3 is opened and gas is supplied from the nozzle 1. At this timing, a thermostat such as bimetal may be provided in the mixing chamber 4 to open / close the valve 3 by this operation, or the user may count the time and manually open the valve 3. The air-fuel mixture starts to react in the catalyst layer 7 of the preheated mixing chamber 4. The reaction surface becomes hot and gradually spreads throughout the mixing chamber 4, and the reaction starts in the catalyst layer 7 of the downstream passage hole 6. The reaction in the passage hole 6 is almost finished in the upstream catalyst layer 7, and the exhaust gas is discharged downstream of the passage hole 6 where the catalyst layer 7 is not present. The catalytic combustion in the catalyst layer 7 has no flame and reacts on the surface of the catalyst, so it is also called flameless combustion.

The reason why a large amount of heat can be generated in such an operation is that the temperature of the catalyst layer 7 is maintained at 900 ° C. or lower which is the heat resistant temperature of the catalyst metal. When a large amount of air-fuel mixture is supplied, the reaction amount of the catalyst layer 7 becomes large and the temperature becomes high. However, since the heat plate 5 removes the reaction heat of the catalyst through the thin catalyst layer 7, the temperature does not rise. If the catalyst layer 7 is too thin, the temperature of the catalyst will be supercooled by the hot plate 5 and the reaction will stop.
This catalyst temperature mainly depends on the amount of combustion per unit area and the thickness of the catalyst layer 7.

The fiber-like porous material is made of aluminum 3
As a result of experimenting by adhering to the passage hole 6 of the hot plate 5 adjusted to 00 ° C., even with the adhering means having the lowest adhesion, if the thickness is 0.5 mm or less, the amount of heat conduction is large and the temperature of the catalyst layer 7 becomes low, making it difficult to continue combustion. Is. In addition, the thickness is 3 mm even in the best contact state.
When it becomes above, it becomes adiabatic and a part of the surface of the catalyst layer 7 becomes too hot, which causes a problem in heat resistance. The thickness of the catalyst layer 7 is preferably in this range, but the optimum thickness varies depending on the operating temperature of the hot plate 5 and therefore must be selected according to the purpose.

The gas reacts violently upstream of the passage hole 6, but as it goes downstream, the exhaust gas increases and the fuel concentration decreases, so the reaction gradually ends. When the reaction is completed, the temperature of the exhaust gas is as high as 500 ° C or higher. Therefore, after completion of the reaction, the hot plate 5 must receive the heat of the exhaust gas, not the reaction heat. Therefore, the catalyst layer 7 downstream of the passage hole 6 obstructs the heat transfer of the exhaust heat and is not necessary. That is, in the upstream where the temperature of the catalyst layer 7 becomes high, the heat plate 5 is heated by direct heat conduction from the catalyst layer 7, and in the downstream where the reaction is completed, the heat plate 5 is heated by heat transfer from the exhaust gas and the inner wall surface of the passage hole 6. is there.

Aluminum can be used at a maximum temperature of about 350 ° C. because of its heat resistance, but when it is used as an iron for generating steam, the temperature is about 120 ° C., and when the hot plate 5 is used as a cooker, it is about 200 ° C. Such temperature adjustment can be performed by opening and closing the valve 3 in accordance with a signal from the temperature detecting unit 9.

Next , the second claim will be described with reference to FIGS. In the configurations shown in FIGS. 1 and 2 described above, when the opening degree of the valve 3 is increased to further increase the combustion amount, the flow velocity of the gas passing through the passage hole 6 is increased. As a result, the amount of fuel gas that cannot complete the reaction in the catalyst layer 7 increases. In addition, the heat exchange efficiency is also reduced in the exhaust heat recovery section downstream. Therefore, both the catalyst layer 7 and the downstream exhaust heat recovery section must be lengthened in proportion to the flow velocity.

The present embodiment aims at increasing the amount of combustion without increasing the length of the passage hole 6 and not decreasing the heat exchange efficiency. The catalyst body 10 is provided downstream of the passage hole 6. The catalyst body 10 is provided in the center of the passage hole 6 opposite to the upstream catalyst layer 7, and the exhaust gas is exhausted between the catalyst body 10 and the hot plate 5. Pass between the walls. The catalyst body 10 is partially supported by a support 11 which is separated from the hot plate 5 but does not obstruct the flow. The effects of such means are as follows. Exhaust gas containing unburned gas that has not been completely partitioned by the catalyst layer 7 upstream of the passage hole 6 reacts on the surface of the downstream catalyst body 10. Since the catalyst body 10 is almost separated from the hot plate 5, it is difficult to be cooled even in the downstream side, the reaction activation temperature is maintained, and the surface is heated by unburned gas and becomes high temperature. That is, the inner wall surface of the passage hole 6 on the downstream side receives the heat of the exhaust gas on the upstream side by convective heat transfer, while receiving the heat generation of the unburned component from the high temperature surface of the catalyst body 10 as radiation. Therefore, the heat exchange efficiency in the downstream is high and the device does not become large even with a large combustion amount.

Further, if the cross-sectional area of the flow path formed by the hot plate 5 and the catalyst body 10 on the downstream side is smaller than that of the flow path formed by the catalyst layer 7 on the upstream side of the passage hole 6, the catalyst body 10 is formed. Radiation is easily transmitted to the hot plate, and the heat transfer of exhaust gas is also improved. Since the gas temperature in the downstream is low and the flow rate is smaller than that in the upstream, the passage resistance is small and therefore the resistance does not increase.

When an infrared absorbing film, for example, a ceramic film having a thickness of about 10 to 50 μm, is formed on the inner wall surface on the downstream side which is heated by the radiation, the radiation heat transfer is further improved. Further, the support 11 may be one protruding from the inner wall surface. In this case, since the protruding portion plays the role of a fin, the recovery of exhaust heat is further promoted, and the heat of the catalyst body 10 can be recovered even by heat conduction at this protruding portion, resulting in higher efficiency.

In the above embodiment, the aluminum heating plate 5 and the mixing chamber 4 are divided into appropriate blocks so that they can be easily manufactured. Alternatively, a heat radiating plate is attached to the outer periphery of the heat plate 5 depending on the application. Alternatively, by providing a catalyst for re-combustion downstream of the outlet of the passage hole 6 and adding a function of purifying the discharged CO when the air ratio becomes equal to or less than the equivalence point, a safer and more efficient compact is achieved. It becomes a heating device.

[0022]

As described above, in the present invention, it is possible to react a large amount of fuel gas in a very small hot plate without producing a flame. Therefore, it can be applied to a portable heating device, and a small and safe heat generating device having high heat efficiency can be provided.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of a heat generating device according to an embodiment of the present invention (BB ′ in FIG. 2).

FIG. 2 is a horizontal sectional view of the device (A-A ′ in FIG. 1).

FIG. 3 is a vertical sectional view showing a heat generating device according to another embodiment of the present invention (BB ′ in FIG. 4).

FIG. 4 is a horizontal sectional view of the device (A-A ′ in FIG. 3).

[Explanation of symbols]

 1 cylinder 4 mixing chamber 5 hot plate 6 through hole 7 catalyst layer 10 catalyst body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Norayoshi Ono, 1006 Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd. (56) References Japanese Patent Publication Sho 60-47485 (JP, B2)

Claims (2)

(57) [Claims] 1. A mixing section for forming a mixture of fuel gas and air.
And made of metal provided downstream in the flow direction of the mixing section.
A hot plate, and a passage portion of the air-fuel mixture provided inside the hot plate,
Flow direction along the inner wall of the upstream part of the flow direction of the passage part
Platinum group metal catalyst on ceramic support formed in parallel with
The supported layered catalyst part and the downstream part in the flow direction of the passage part
Has an exhaust path that is formed and whose inner surface is part of the hot plate
The air-fuel mixture burned on the surface of the layered catalyst layer.
A heat generating device in which the exhaust gas is later cooled in the exhaust path . 2. A second catalyst body is inserted in the exhaust passage.
Therefore, a part of the second catalytic body is an inner wall surface of the exhaust path.
The second catalyst body is supported by a more projecting support portion.
The heat generating device according to claim 1 , wherein an inner wall surface of the exhaust path faces the space through a space .