JP2000246062A - Apparatus for catalyst for cleaning of exhaust gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heat an odor decomposition catalyst with a small electric power and in a short time by taking an enough measure for electric insulation. SOLUTION: This apparatus is provided with a box body 5 with a cavity for gas passage, a water-repellent heat-resistant insulating film 6 provided on the surface of the inlet side of this box body and thin metal sheets 8 arranged approximately at right angles in the cavity for gas passage on the downstream side thereof and each with an odor decomposition catalyst 10 formed through a heat-resistant insulating layer 9 on the surface. In addition, by water repellent action and insulating action of the water-repellent heat-resistant insulating film, electrically conductive communication with an exhaust gas generating instrument generated by water content stuck on the thin metal sheet when exhaust gas passes through the cavity for gas passage is intercepted. It is possible thereby to prevent electric current passing through the thin metal sheet from passing through to the exhaust gas generating instrument side. In addition, as the odor decomposition catalyst is directly provided on the thin metal sheet through the heat-resistant insulating layer, it is possible to heat the catalyst with a small electric power and in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying catalyst device equipped with a heater for purifying harmful components in exhaust gas, and more particularly to an exhaust gas purifying catalyst device which can be used in exhaust gas having a high moisture content.

[0002]

2. Description of the Related Art In general, various exhaust gas purifying catalyst devices having a catalyst for purifying exhaust gas have been proposed.

FIG. 4 shows a conventional exhaust gas purifying catalyst device described in Japanese Patent Application Laid-Open No. Hei 5-301048.
1b is used as a carrier of a catalyst, and an energizing portion 3 in which an insulating inorganic material (not shown) is coated on an expanded stainless steel plate 2 (also referred to as lath netting) which is capable of conducting electricity by connecting the catalyst component is used as a catalyst component. (Not shown) is described.

[0004] A conventional exhaust gas purifying catalyst device is employed in the heating cooker described in JP-A-4-29722. This exhaust gas purifying catalyst device is sandwiched between a first oxidation catalyst and a second oxidation catalyst of a honeycomb formed body having a large number of small holes through which cooking gas passes, and heats these catalysts. For this purpose, an electric heater having a round bar formed in a meandering shape, and a stainless steel exhaust passage in which the catalyst and the electric heater are arranged in the internal space thereof are provided. The first oxidation catalyst and the second oxidation catalyst are compositions in which platinum and palladium are supported on a carrier layer of a honeycomb formed body containing aluminum oxide as a main component. The electric heater is an electrical insulation measure in which a heater wire is housed inside a meandering metal tube, and generates heat when energized to heat the surrounding first and second oxidation catalysts.

[0005]

However, in a conventional exhaust gas purifying catalyst apparatus in which a catalyst component is supported on an expanded stainless steel sheet with an insulating inorganic substance interposed,
Since no electrical insulation measures are taken against moisture, when installed in an exhaust gas generator, the moisture contained in the exhaust gas adheres to the surface of a stainless steel plate that can conduct electricity. The generator is electrically conductive. Therefore, there is a problem that the stainless steel plate cannot be used unless measures are taken to prevent electrical conduction between the stainless steel plate and the exhaust gas generator.

On the other hand, an exhaust gas purifying catalyst device used in a conventional heating cooker has a structure in which a large-volume first oxidation catalyst and a second oxidation catalyst sandwich a small electric heater. There is a problem that a large electric power and a long heating time are required for heating the oxidation catalyst and the second oxidation catalyst.

The present invention solves the above-mentioned problems of the prior art, and provides an exhaust gas purifying catalyst device which performs electrical insulation and raises the temperature of the catalyst in a short time with small electric power.

[0008]

According to the present invention, in order to solve the above-mentioned problems, a water-repellent heat-resistant insulating film is formed on the inlet-side surface of a gas-passing cavity of a heat-resistant insulating casing, and this repellent film is formed. This is an exhaust gas purifying catalyst device provided with an odor decomposition catalyst formed in a gas passage cavity downstream of a water-resistant heat-resistant coating in a surface of a thin metal plate that generates heat by energization via a heat-resistant insulating layer.

According to the above configuration, the exhaust gas purifying catalyst device used by being attached to the exhaust passage of an exhaust gas generating device or the like is provided with a water repellent and insulating action of the water repellent heat-resistant insulating film on the inlet side in the gas passage cavity. In addition, the electrical continuity with an exhaust gas generating device or the like caused by moisture adhering to the metal sheet is cut off. Therefore, the current flowing through the thin metal plate is prevented from flowing through the device. Further, since the heat generated by the thin metal plate is directly transmitted to the odor decomposition catalyst via the heat-resistant insulating layer, the heating of the catalyst requires only a small amount of power, and the temperature rises in a short time.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention can be embodied in the embodiments described in the claims.

That is, according to the first aspect of the present invention, there is provided a heat-resistant insulating casing having a gas passage cavity therein, and a water-repellent heat-resistant insulation film provided on an inlet side surface of the gas passage cavity. A metal sheet provided in a gas passage cavity downstream of the water-repellent heat-resistant insulating film and having a plurality of holes and generating heat by energization; a heat-resistant insulating layer formed on the surface of the metal sheet; And the odor decomposition catalyst formed on the surface.

In the above structure, the water-repellent heat-resistant insulating film is provided on the inlet side surface of the gas passage cavity of the housing, and the odor decomposition catalyst is provided in the gas passage cavity downstream of the water-repellent heat-resistant insulating film. The water-repellent heat-resistant insulating film on the inlet side in the gas passage cavity,
The electrical continuity with the equipment to which the exhaust gas purifying catalyst device is attached, which is caused by the moisture adhering to the metal sheet, is cut off.
Therefore, the current flowing through the metal sheet is prevented from flowing through the equipment due to the heating of the odor decomposition catalyst. Further, since the heat generated by the thin metal plate is directly transmitted to the odor decomposition catalyst via the heat-resistant insulating layer, the heating of the catalyst requires only a small amount of power, and the temperature rises in a short time.

According to a second aspect of the present invention, a housing is formed by joining a plurality of divided housings having heat and heat insulation.
Further, a groove may be provided on the inner surface of the divided housing, a metal sheet having an odor decomposition catalyst on the surface may be fitted into the groove, and the groove may be disposed substantially perpendicular to the gas passage direction.

In the above configuration, since the thin metal plate is fitted in the groove and disposed substantially vertically in the gas passage cavity of the housing, the exhaust gas flowing in the gas passage cavity passes through the thin metal plate without leaking. The decomposition rate of odor components is increased by contact with the odor decomposition catalyst. Also, it is assembled by fitting a metal sheet into the groove of the divided housing and joining the divided housings together,
It becomes easy to work. In addition, if the housing is made of a heat-resistant heat-insulating material such as ceramics, the heat-insulating effect is enhanced, and as a result, the temperature of the odor decomposition catalyst is also increased, and the decomposition rate of odor components is further increased. Furthermore, since the metal sheet is disposed substantially perpendicular to the gas passage direction in the gas passage cavity, the exhaust gas can effectively pass through the holes of the metal sheet to reduce pressure loss and contact with the odor decomposition catalyst. And improve the decomposition rate of odor components.

The invention according to claim 3 is the same as the invention according to claim 2.
In the description, it can be implemented by providing a water-repellent heat-resistant insulating film on the inlet-side joining surface and the inlet-side front end face of the divided casings constituting the gas passage cavity.

In the above configuration, the housing is divided into a plurality of parts,
When the divided housings are joined to each other to form a housing,
There is a minute gap in the joint surface of the split housing, and the electrical conduction through the dew condensation water leaking from this causes the repellency of the water-repellent heat-resistant insulating coating on the joint surface with the device to install the exhaust gas purification catalyst device and the front end surface. The current flowing through the sheet metal, which is interrupted by the water action and the insulating action, is prevented from flowing to the equipment.

The invention described in claim 4 is the same as the claim 2.
In the description, it can be carried out by providing a water-repellent heat-resistant insulating film on the outer peripheral surface on the entrance side of the divided casing constituting the gas passage cavity.

In the above configuration, when the exhaust gas generator is used in a high-temperature and high-humidity environment, moisture also adheres to the outer peripheral surface of the casing constituting the exhaust gas purifying catalyst device. Due to the insulating action, conduction between the metal sheet and the device via the moisture is blocked, and the current flowing through the metal sheet is prevented from flowing to the device.

According to a fifth aspect of the present invention, the water-repellent heat-resistant insulating film is a film containing a fluororesin as a main component. This can be implemented by using the exhaust gas purifying catalyst device described above.

In the above construction, since the water-repellent heat-resistant insulating film uses a fluororesin system having excellent water repellency, the current flowing through the thin metal plate is further prevented from flowing into the exhaust gas generating equipment and the like. Moreover, the fluororesin has excellent heat resistance, and does not deteriorate even when exposed to high-temperature exhaust gas.

According to a sixth aspect of the present invention, there is provided the exhaust gas purifying catalyst apparatus according to the second aspect, wherein the fixing member sandwiches and fixes a joint portion of the plurality of divided housings constituting the housing from outside. Can be implemented.

In the above configuration, the casing of the exhaust gas purifying catalyst device is assembled by joining a plurality of divided casings to each other and sandwiching and fixing the joined portion from the outside with a fixing member, thereby simplifying the operation. Done and securely fixed.

Further, the invention according to claim 7 can be implemented by processing a stainless steel sheet into a lath net shape and processing it into a corrugated shape to form a metal thin plate.

In the above structure, the heat capacity and weight percentage of the metal sheet are small and the hole opening ratio is large due to the lath mesh and corrugated shape of the stainless steel sheet. At the same time, the stainless steel sheet has excellent corrosion resistance, and the lath-like and corrugated processing increases the heat generation area per unit volume, resulting in a high heat generation temperature.

The invention according to claim 8 can be carried out by forming a heat-resistant insulating layer from an enamel containing at least 10 to 45% by weight of aluminum in a stainless steel sheet obtained by processing a thin metal sheet into a lath net shape. In the above structure, at least aluminum in the enamel is 10 to 45% by weight.
When it is contained, the aluminum expands in volume when baked, and forms a coating of aluminum oxide on its surface to become an electric non-conductor. Therefore, the enamel becomes a porous heat-resistant insulating layer,
No thermal deformation of the thin metal plate or peeling of the enamel occurs when the enamel is baked.

According to a ninth aspect of the present invention, there is provided a stainless steel sheet obtained by processing a thin metal sheet into a lath net, wherein the heat-resistant insulating layer is 10 to 45% by weight of aluminum and 10 to 45% by weight of titanium oxide.
It can be implemented by forming each with an enamel containing at least 25% by weight.

In the above construction, if aluminum is contained in the enamel at 10 to 45% by weight, the enamel becomes a porous heat-resistant insulating layer by baking, and the enamel becomes 10 to 25% by weight of titanium oxide.
Further becomes a heat-resistant insulating layer having excellent water resistance. Accordingly, the metal sheet does not undergo thermal deformation when the enamel is baked, and the enamel does not peel off even when exposed to steam for a long time.

[0028] The invention according to claim 10 provides a carrier layer obtained by attaching and firing a sol containing aluminum hydroxide as a main component, and at least one of platinum and palladium carried on the carrier layer, or It can be carried out by forming an odor decomposition catalyst formed of a noble metal having both of them on the surface of the heat-resistant insulating layer according to the eighth or ninth aspect.

In the above structure, aluminum is added in 10 to
The enamel mixed with 45% by weight becomes a porous heat-resistant insulating layer and adheres to the surface of the stainless steel sheet as described above. Accordingly, when the sol of aluminum hydroxide is adhered to the enamel, the sol penetrates into the voids of the porous enamel and becomes firmly adhered to the porous alumina by firing. In addition, one or more noble metals of platinum or palladium having high activity are firmly adhered to the porous carrier layer because they are supported on the porous carrier layer. Therefore, the odor decomposition catalyst exhibits excellent purification characteristics and adhesion.

The invention according to claim 11 is characterized in that a non-energized ventilation plate made of stainless steel having a plurality of holes is provided substantially vertically in the gas passage cavity of the housing downstream of the thin metal plate, An oxide film formed by heat treatment on the surface of the carrier layer, a carrier layer obtained by adhering a sol containing aluminum hydroxide as a main component to the oxide film and firing, and at least one of platinum and palladium supported on the carrier layer, Alternatively, it can be carried out by forming an odor decomposition catalyst provided with a noble metal having both.

In the above configuration, if the ventilation plate is disposed downstream of the metal sheet, the ventilation plate reduces the speed of passing the exhaust gas in the gas passage cavity, and the reaction time of the surface of the metal sheet with the odor decomposition catalyst is prolonged. As the odor decomposition rate increases, the odor decomposition catalyst is also formed on the surface of the downstream ventilation plate, so that the number of times of reaction with the catalyst increases and the odor component decomposition rate further increases.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a longitudinal sectional view of an exhaust gas purifying catalyst apparatus according to Embodiment 1 of the present invention. This exhaust gas purifying catalyst device has a heat-resistant and insulating cylindrical housing 5 having a gas passage cavity 4 therein through which cooking gas or the like passes, and a gas passage cavity 4 of the housing 5 on the inlet side surface. Water-repellent heat-resistant insulating film 6 formed by applying a coating of fluoroethylene resin
And a metal sheet 8 disposed in the gas passage cavity 4 on the downstream side of the water-repellent heat-resistant insulating film 6 in a direction substantially perpendicular to the exhaust gas passage direction and having a plurality of small holes 7 and generating heat when energized.
And a heat-resistant insulating layer 9 formed on the surface of the metal sheet 8;
An odor decomposition catalyst 10 formed on the surface of the heat-resistant insulating layer 9 and operated by being heated by the heat generated by the thin metal plate 8.

The housing 5 is formed of a silica-alumina ceramic, for example, is molded as a plurality of divided housings having a bottom portion and a cover portion, and the bottom portion and the cover portion are fitted to each other to form a gas passage cavity 4 therein. The shape is devised so that is formed. After the casing 5 is molded, a coating of tetrafluoroethylene resin is applied to the inlet side surface of the gas passage cavity 4 to form a water-repellent heat-resistant insulating film 6. Subsequently, a thin metal plate 8 is disposed substantially vertically in the gas passage cavity 4 on the downstream side of the water-repellent heat-resistant insulating film 6 of the housing 5, and a fine metal sheet 8 is formed between the lid and the bottom constituting the housing 5. It is completed by sealing hermetically with an inorganic adhesive so that no gap is generated.

The metal thin plate 8 is a stainless steel thin plate processed into a lath net shape and further processed into a corrugated shape, and has a heat-resistant insulating layer 9 made of an enamel and a sol containing aluminum hydroxide as a main component. And a calcined alumina-based carrier layer, and an odor decomposition catalyst 10 composed of a noble metal of platinum and palladium carried on the carrier layer.
The thin metal plate 8 is a 65 μm-thick ferrite stainless steel foil body containing at least 18% by weight of chromium and 3.5% by weight of aluminum. Was about 85%, and even when the heat-resistant insulating layer 9 was provided on the surface and the odor decomposition catalyst 10 was further formed on the surface, the hole opening ratio was about 75%.

In the first embodiment, the exhaust gas purifying catalyst device is provided at the exhaust port of a heating cooker of an electric oven.
Attach the entrance side of and use. Then, the metal sheet 8 is energized in advance, and the exhaust gas enters the gas passage cavity 4 from the inlet side of the housing 5 as shown by the arrow, passes through the portion having the water-repellent heat-resistant insulating film 6, and further passes through the hole 7. Odor decomposition catalyst 1
When it comes into contact with zero, the odor component is decomposed and discharged outside as shown by the arrow.

With respect to a prototype in which such an exhaust gas purifying catalyst device according to the first embodiment is attached to an electric oven, the result of an experiment to determine the operation and effect will be described below. The metal sheet 8 for heating the odor decomposition catalyst 10 of the exhaust gas purifying catalyst device is energized at the same time as the energization of the heating heat source of the electric oven, unless otherwise specified.
The measurement items for determining the effect are five items: insulation resistance, power consumption and temperature arrival time, cooking gas leak status, and hydrocarbon removal rate.

The insulation resistance was determined by adding 300 cc of water in the cooking chamber to 3
Evaporate in advance for 0 minutes to keep the cooking chamber moist, and then measure the insulation resistance between the thin metal plate 8 and the electric oven when two pieces of 500 g were cooked for 30 minutes. It represents the lowest value. The insulation resistance was measured using a measuring instrument whose maximum value was 300 MΩ.

The power consumption and the time required to reach the predetermined temperature are the power consumption of the exhaust gas purifying catalyst device required to reach 400 ° C., which is the temperature at which the odor decomposition catalyst 10 works effectively, and the time required until the temperature reaches 400 ° C. It is the required time.

The cooking gas leakage condition is a cooking gas leakage condition from a place other than the exhaust gas purifying catalyst device when two young children are cooked, and is obtained as a clue to know the pressure loss of the exhaust gas purifying catalyst device. It is a thing.

The hydrocarbon removal rate was calculated from the concentration in the cooking chamber and the concentration at the outlet of the exhaust gas purifying catalyst device as the hydrocarbon concentration when two young routs were cooked.

The results measured under the above conditions are shown in Table 1.

In the conventional product, the catalyst device is constituted by a first oxidation catalyst and a second oxidation catalyst having a large number of small holes through which cooking gas passes, and an electric heater sandwiched between the first oxidation catalyst and the second oxidation catalyst. , Which are directly mounted inside a stainless steel exhaust passage. The first oxidation catalyst and the second oxidation catalyst are formed by honeycomb having a large number of small pores, and have a composition in which platinum and palladium are supported on a carrier layer containing aluminum oxide as a main component. The upper limit of the hole opening ratio was 45%. The electric heater is an electrical insulation measure in which a heater wire is housed inside a meandering metal tube, and generates heat when energized to heat the surrounding first and second oxidation catalysts. The apparent dimensions of the catalyst layer and the amounts of platinum and palladium were the same as those of the inventive product of Example 1.

The reference product is an exhaust gas purifying catalyst device in which the water-repellent heat-resistant insulating film 6 is omitted from the product of the present invention.

[0045]

[Table 1]

The product of the present invention consumes less power in the exhaust gas purifying catalyst device as compared with the conventional product, rises to a predetermined temperature in a short time, and does not leak cooking gas from anything other than the exhaust gas purifying catalyst device. It is clear that it has the advantage of high hydrocarbon removal rates. Further, it is clear that the product of the present invention has a higher insulation resistance than the reference product and is electrically insulated.

The excellent advantages of the product of the present invention are as follows.

The reason for the high insulation resistance is that a water-repellent heat-resistant insulating film 6 made of tetrafluoroethylene resin having excellent water-repellent action and electrical insulating action is formed on the inlet side surface of the gas passage cavity 4 of the housing 5. As a result, the electric continuity between the exhaust gas purifying catalyst device and the electric oven through the moisture attached to the gas passing cavity 4 from the electric oven and condensed due to dew condensation is caused by the water-repellent heat-resistant insulating film. 6 because it is cut off.
In addition, since the conventional product used the electric heater which was previously electrically insulated, it was excellent in insulation resistance. On the other hand, the reference product has a period until the metal thin plate 8 is maintained at about 150 ° C. or higher by energization (approximately 10 seconds after energization) through electrical conduction through moisture previously evaporated in the cooking chamber. . for that reason,
During this time, the insulation resistance value was small, for example, 1 MΩ immediately after energizing the thin metal plate 8 and 5 MΩ after 10 seconds. When the time exceeded 10 seconds, the insulation resistance increased, and after 1 minute, it reached 300 MΩ.

The reason why the power consumption is low and the temperature rises to the predetermined temperature in a short time is that the thin metal plate 8 is processed into a lath net having a high hole opening ratio and has a corrugated shape. This is because the heat capacity is reduced, and the heat generation area per unit volume is also increased.

The reason why the cooking gas does not leak is that even if the thin metal plate 8 is formed in a lath net shape and the heat-resistant insulating layer 9 and the odor decomposition catalyst 10 are formed on the surface thereof, the hole opening ratio is as large as 75%, and the pressure is high. This is because the loss is small. In this regard, the conventional product has a problem that the cooking gas leaks from the front door of the electric oven due to a large pressure loss due to the small hole opening ratio of 45%.

The reason why the hydrocarbon removal rate is high is that the surface area is increased due to the high hole opening ratio of 75%.

The material of the thin metal plate 8 is suitably nickel-chromium alloy, iron-nickel-chromium alloy, iron-nickel alloy, iron-chromium-aluminum alloy. This is because the heat resistance is excellent because of high specific resistance, and the workability is excellent, so that it is easy to form a plurality of holes through which gas is passed by making holes in the thin plate. is there.

On the other hand, the material of the heat-resistant insulating layer 9 formed on the surface of the thin metal plate 8 is appropriate because glass, enamel, alumina sol, silica sol, polysiloxane and polyphosphoric acid have excellent adhesion. A heat-resistant insulating layer was formed by attaching a viscous aqueous solution to the metal surface and firing it.
In these combined products, an enamel heat-resistant insulating layer 9 is formed on a stainless steel thin plate 8 made of an iron-nickel-chromium alloy, an iron-nickel alloy, or an iron-chromium-aluminum alloy.
The product of the present invention formed with is particularly excellent in adhesion. The reason for this is that the iron component contained in the thin metal plate 8 and the glass component contained in the enamel react and fix the enamel during firing. Particularly, among these, an iron-chromium-aluminum alloy is strongly fixed because the aluminum component contained in the metal sheet 8 reacts with the glass component contained in the enamel,
The adhesion was the best. As the iron-chromium-aluminum alloy, a composition containing at least 13 to 33% by weight of chromium and 3 to 8% by weight of aluminum is commercially available, and the composition is not particularly limited within this composition range. The product had advantages over other metal heating materials in heat resistance, corrosion resistance, mechanical strength, and non-resistance.

On the other hand, the more porous the enamel, the better the deformation of the thin metal plate 8 when baked. The composition of the porous enamel used in the experiment is shown below. Enamel is glass component 15
% By weight, 30% by weight of a metal oxide pigment, 35% by weight of aluminum, and 20% by weight of titanium oxide. Each of the compositions is allowed to fluctuate up to ± 5% by weight. Used what is.

The odor decomposition catalyst 10 comprises platinum, palladium,
Oxidation reaction catalytically active substances such as manganese oxide, cobalt oxide, copper oxide, and iron oxide are suitable.
Or a method in which an alumina or silica-based carrier is formed on the surface of the heat-resistant insulating layer 9 and supported on this carrier.

The housing 5 is suitably made of mica (also called mica) or ceramic. The water-repellent heat-resistant insulating film 6
Fluororesin, silicone resin and polysiloxane resin are suitable.

(Embodiment 2) FIGS. 2 and 3 show Embodiment 2 of the present invention. FIG. 2 is an exploded perspective view of an exhaust gas purifying catalyst device, and FIG. 3 is a longitudinal sectional view of the device. The second embodiment is different from the first embodiment only in that the casing of the exhaust gas purifying catalyst device is specifically described. Other parts having the same functions and functions and effects are the same as the first embodiment. The detailed description is omitted by attaching the reference numerals, and different points are mainly described.

The housing 5 has a ceramic concave housing bottom 11 serving as two vertically divided housings, and a ceramic inverted concave housing lid for closing the housing bottom 11. The joint surface of the two is hermetically sealed with an inorganic adhesive to form a gas passage cavity 4 inside. The water-repellent and heat-resistant insulating films 6a and 6b are formed by applying a tetrafluoroethylene resin on the inlet-side surfaces of the gas passage cavities 4 of the housing bottom 11 and the housing lid 12. On the other hand, grooves 13a and 13b are provided on the inner peripheral surface of the gas passage cavity 4 on the downstream side of the water-repellent heat-resistant insulating coatings 6a and 6b of the housing bottom 11 and the housing lid 12. The outer periphery of the thin metal plate 8 that generates heat by being energized is fitted so as to be substantially perpendicular to the exhaust gas passage direction. Reference numerals 14a and 14b denote electrodes provided at both ends of the thin metal plate 8, from which an alternating current power is applied to cause the thin metal plate 8 to generate heat. Reference numerals 15a, 15b, and 15c denote the electrodes 14 on the surfaces of the housing bottom 11 and the housing lid 12 that are joined to each other.
a, 14b are recesses provided to pass through.

In the second embodiment, the gas passage cavity 4
Exhaust gas flowing through the inside is such that the outer periphery of the thin metal plate 8 is
3b, it does not flow (leak) without passing through the hole 7 of the sheet metal 8, and effectively contacts the odor decomposition catalyst 10 of the sheet metal 8, and does not have the grooves 13a, 13b. The decomposition rate of the odor component can be further increased. In addition, since the housing 5 is formed of ceramic, the heat insulating effect is enhanced, and the temperature of the odor decomposition catalyst 10 is higher than in the case where mica is used, so that the decomposition rate of odor components can be improved. Furthermore, the surfaces of the housing bottom 11 and the housing lid 12 that are bonded to each other are hermetically sealed with an inorganic adhesive so as not to have minute gaps, and the fluororesin-based water-repellent heat-resistant insulating films 6a and 6b are formed. Due to the water-repellent action, it is possible to significantly reduce leaked dew condensation water. Further, since the thin metal plate 8 is disposed substantially perpendicular to the gas passage direction in the gas passage cavity 4, the exhaust gas can effectively pass through the holes 7 of the thin metal plate 8, reducing the pressure loss, and decomposing the odor. The contact with the catalyst 10 is improved, and the decomposition rate of the odor component is increased.

In the second embodiment, the housing 5 is connected to the housing bottom 1.
1 and the housing lid 12 are vertically divided into two parts.
The shape is not limited to two, and may be divided in the left-right direction. The shape is not limited to a rectangular cross section, but may be any shape such as an ellipse or a circle as long as it can fulfill the initial purpose. Either the housing bottom part 11 or the housing lid part 12 may be combined as a simple flat plate lid or bottom.

(Embodiment 3) Embodiment 3 of the present invention relates to an arrangement structure of a water-repellent heat-resistant insulating film in a casing of an exhaust gas purifying catalyst device. And the third embodiment is the second embodiment.
Example 1 using FIGS. 2 and 3 used in the description of FIG.
Parts having the same functions and effects as those of the second embodiment are denoted by the same reference numerals, detailed description thereof will be omitted, and different points will be mainly described.

The housing bottom 11 and the housing lid 12 of the housing 5
In addition to the inlet-side surface of the gas passage cavity 4, the housing bottom 1
1 and the inlet-side joining surfaces 16a and 16b of the housing lid portion 12 and the inlet-side front end surfaces 17a and 17b facing the mounting side to the device.
Also, a fluororesin-based water-repellent heat-resistant insulating film is formed.

In the third embodiment, the gas passage cavity 4
Exhaust gas flowing through the inside is condensed on the inlet side of the housing bottom 11 and the housing lid 12. In general, a large gap is formed between the joining surface of the housing bottom portion 11 and the housing lid portion 12, and if there is no water-repellent heat-resistant insulating coating on the joining surface, electric conduction occurs via a large amount of dew condensation water, and the metal sheet The current flowing in 8 flows into the electric oven.

In the present invention, however, the water-repellent and heat-insulating films of the water-repellent and heat-resistant insulating films on the inlet-side joining surfaces 16a and 16b and the inlet-side front end surfaces 17a and 17b of the housing 5 provide
Inlet-side joining surfaces 16a, 16b and inlet-side front end face 17
The water leaking from the a and 17b is greatly reduced, and the electric current flowing through the thin metal plate 8 can be prevented from flowing into the electric oven by interrupting the electrical conduction through the leaking water. Further, by forming a water-repellent heat-resistant insulating film on the entrance-side joining surfaces 16a, 16b and the entrance-side front end surfaces 17a, 17b of the casing 5, the joining between the two is performed by the casing bottom 11 and the casing lid 12. It can be realized by a simple method such as tying the outer periphery with a fixing member such as a band, and the housing 5 can be manufactured in a short time using simple manufacturing equipment.

(Embodiment 4) Embodiment 4 of the present invention relates to an arrangement structure of a water-repellent heat-resistant insulating film in a casing of an exhaust gas purifying catalyst device. And the fourth embodiment is the second embodiment.
2 and 3 used in the description of the first embodiment, portions having the same functions and effects as those in the first, second, and third embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted. The explanation will be focused on the process.

The housing bottom 11 and the housing lid 12 of the housing 5
Inlet side surface and inlet side joining surface 1 of gas passage cavity 4
6a, 16b, the entrance-side front end faces 17a, 17b, as well as the entrance-side outer peripheral surface 18 of the casing bottom 11 and the casing lid 12.
A water-repellent heat-resistant insulating film of a fluororesin type is also formed on a and 18b.

In the fourth embodiment, when the electric oven is generally used in a high-temperature and high-humidity environment, dew condensation adheres to the outer peripheral surface of the ceramic housing 5 constituting the exhaust gas purifying catalyst device. Certain entrance-side outer peripheral surfaces 18a, 18
If there is no water-repellent heat-resistant insulating film in b, the current flowing through the thin metal plate 8 via the attached moisture flows toward the electric oven.

However, in the present invention, conduction is interrupted by the water repellent action and the insulating action of the water-repellent heat-resistant insulating films provided on the outer peripheral surfaces 18a and 18b on the entrance side of the housing 5, and the current flowing through the thin metal plate 8 is reduced. It can be prevented from flowing to the electric oven side.

(Embodiment 5) Embodiment 5 of the present invention relates to the material of the water-repellent heat-resistant insulating film in the casing of the exhaust gas purifying catalyst device.
-Portions having the same function and operation and effect as those of the fourth embodiment are denoted by the same reference numerals, detailed description thereof will be omitted, and different portions will be mainly described. The water-repellent heat-resistant insulating coatings 6a, 6b face the inlet-side surface of the gas passage cavity 4 of the housing 5, the inlet-side joining surfaces 16a, 16b of the housing bottom 11 and the housing lid 12, and the mounting equipment. Entrance-side front end surfaces 17a, 17b, and entrance-side outer peripheral surfaces 18a, 18 of the housing bottom 11 and the housing lid 12.
b. The material of the water-repellent heat-resistant insulating film 6, 6a, 6b is made of a resin containing 100% by weight of a fluorine resin, a resin containing 80% by weight of a fluorine resin, a resin containing 60% by weight of a fluorine resin, a resin containing 50% by weight of a fluorine resin,
An experiment was conducted to confirm the effect of a resin containing 40% by weight of a fluorine resin, a silicone resin, and a polysiloxane resin.

The results of the determination of the operation and effect of the prototype in which the exhaust gas purifying catalyst device according to the fifth embodiment is attached to an electric oven will be described below.

In the experiment, the insulation resistance was measured in the cooking chamber 10 with water 3
00cc was evaporated in advance for 30 minutes to keep the cooking chamber moist, and then the insulation resistance between the thin metal plate 8 and the electric oven when two pieces of 500g were cooked for 30 minutes. The measurement was performed every time, and the judgment was made based on the magnitude of the minimum insulation resistance value. The results of measuring the minimum insulation resistance value during operation of the electric oven by changing the material of the water-repellent heat-resistant insulating film are shown in Table 2.

[0072]

[Table 2]

As is clear from the results, it is understood that the water-repellent heat-resistant insulating film is excellent in insulation resistance when it is made of a fluororesin. Further, it is understood that when the resin contains 60% by weight or more of the fluorine resin, the insulation resistance is sufficiently secured. Furthermore, since it is a heat-resistant fluororesin, especially if it is a tetrafluoroethylene resin having excellent heat resistance, excellent durability can be maintained for a long time even at a cooking temperature of around 250 ° C.

(Embodiment 6) Embodiment 6 of the present invention relates to a structure for fixing a casing of an exhaust gas purifying catalyst device, using FIGS. 2 and 3 used in the description of Embodiment 2. Portions having the same functions and effects as those of the first to fourth embodiments are denoted by the same reference numerals, detailed description thereof will be omitted, and different portions will be mainly described.

The housing 5 is composed of a concave housing bottom 11 as two divided housings divided vertically and an inverted-concave housing lid 12 for closing the housing bottom 11. I have. The upper and lower housing bottoms 11 and the housing lid 12 are integrally joined by fitting metal fixing members 24a and 24b formed in a U-shape from the left and right. The right and left one fixing members 24a include a base 19a, an upper side 20a and a lower side 2
1a, and the other fixing member 24b also has a base 19
b, an upper side 20b and a lower side 21b.
Also, upper sides 20a and 20b of fixing members 24a and 24b
Upper and lower tongue portions 22a and 22b and lower tongue portions 23a and 23b are provided on the lower side portions 21a and 21b, respectively. Reference numerals 25a and 25b denote upper recesses provided on the left and right upper surfaces on the outer side of the entrance side of the housing lid portion 12, and the upper tongue portions 22a and 22b of the fixing members 24a and 24b are engaged with each other. Also, 26
a and 26b (not shown) are also fixed members 24a and 2b.
4b is a lower depression provided on the left and right sides of the outer bottom surface on the entrance side of the housing bottom 11 where the lower tongue portions 23a and 23b are engaged. 27a and 2
7b are bases 19a and 19b of the fixing members 24a and 24b.
The casing 5 is attached to the exhaust port of the electric oven at a front end of the electric oven and bent outward at a right angle.

In the sixth embodiment, the upper sides 20a and 20b of the fixing members 24a and 24b are provided on the upper and lower surfaces of the upper and lower case bottoms 11 and the case lid 12 joined to each other.
And the lower sides 21a and 21b are tightly fitted. And
Upper tongue portions 22a and 22 fitted with fixed members 24a and 24b
b and lower tongues 23a and 23b are formed in upper recesses 25a and 25b of the housing lid 12 and lower recesses 26 of the housing bottom 11 respectively.
a and 26b are strongly engaged by the elasticity of the metal.

As described above, the left and right fixing members 24a and 24b
Bottom 11 and housing lid 12 fixed together by
Are firmly fixed by the upper tongue portions 22a and 22b and the lower tongue portions 23a and 23b of the upper sides 20a and 20b and the lower sides 21a and 21b of the fixing members 24a and 24b so as not to move in the vertical direction. Fixing members 24a and 24
b are firmly fixed by the bases 19a and 19b so as not to move in the left-right direction.

In the sixth embodiment, the fixing members 24a and 24b are formed in a right and left U-shape. It is needless to say that the shape may be any shape as long as the fixing force can be exerted along the shape of the housing bottom portion 11 and the housing lid portion 12 joined together.

(Embodiment 7) Embodiment 7 of the present invention relates to the shape and arrangement of a thin metal plate of an exhaust gas purifying catalyst device, using FIGS. 2 and 3 used in the description of Embodiment 2. Portions having the same function and effect as those of the first to sixth embodiments are denoted by the same reference numerals, detailed description thereof will be omitted, and different portions will be mainly described.

The metal thin plate 8 is a thin stainless steel foil formed by forming a plurality of small holes 7 by processing it into a lath mesh as described in the first embodiment, and further processing it into a corrugated shape. An insulating layer 9 and an odor decomposition catalyst 10 are formed on the surface thereof. And the metal sheet 8 is as shown in FIG.
As shown in the figure, it is arranged substantially perpendicular to the gas passage direction in the gas passage cavity 4 of the housing 5.

In Example 7, in order to determine the effect of the metal sheet 8, various metal sheets having different shapes and arrangements were trial-produced, and the maximum temperature at 50 W power consumption and the cooking gas Table 3 shows the results of an experiment conducted on three items, ie, the leakage state and the hydrocarbon removal rate (also referred to as the HC removal rate).

Prototype No. 1 is the present embodiment shown in FIG. 3, in which a stainless steel foil processed into a lath net shape and further processed into a corrugated shape is arranged substantially perpendicular to the gas passing direction. It is. Prototype No. 2 is a stainless steel foil body that has been punched by a press and then further processed into a corrugated shape, and is arranged substantially perpendicular to the gas passage direction. Prototype No. 3 is a flat plate shape processed into a lath net shape. The stainless steel foil is arranged substantially perpendicularly to the gas passing direction, and the prototype No. 4 is further processed into a lath net shape, and then the corrugated stainless steel foil is further processed in the gas passing direction. Are arranged substantially in parallel.

In each of the prototypes, the surface of the stainless steel foil body was composed of a heat-resistant insulating layer 9 made of enamel, a carrier layer mainly composed of aluminum oxide, and platinum and palladium noble metals supported on the carrier layer. The odor decomposition catalysts 10 are sequentially formed, and are confirmed by being attached to an exhaust port of an electric oven as an exhaust gas purifying catalyst device.

[0084]

[Table 3]

In the prototype No. 1 of this embodiment, since a plurality of holes 7 are formed by processing a stainless steel foil body into a lath mesh, a thin metal plate having a small heat capacity and a small weight% and a large hole opening ratio can be obtained. Thus, there was no problem that the pressure loss was reduced and the cooking gas leaked from the front door of the electric oven. In addition, since the lath net-shaped stainless steel foil is further processed into a corrugated shape, the heat generation area per unit volume is increased, a high temperature is obtained, and the decomposition of the hydrocarbon removal rate is increased. Further, since the thin metal plate 8 is arranged in a direction substantially perpendicular to the gas passage direction, the gas can effectively pass through the holes 7 of the lath net and the contact with the odor cracking catalyst 10 can be improved, and the hydrocarbon can be removed. The rate is even higher.

The prototype No. 2 had a hole opening ratio of 50% at the maximum because the hole was formed by pressing. As a result, the resistance decreased, the temperature reached slightly decreased, the hydrocarbon removal rate decreased, and conversely, the hole opening ratio could not be increased, resulting in a large pressure loss and the problem that cooking gas leaked from the front door of the electric oven. I am ineligible.

It is understood that the prototype No. 3 is a thin metal plate without any corrugated processing, so that the heat generation area per unit volume is small, the temperature is low, and the hydrocarbon removal rate is also low.

In Prototype No. 4, since the processed thin metal plate is disposed substantially parallel to the gas passage direction, a considerable amount of gas passes between the thin metal plates and the contact with the odor decomposition catalyst becomes poor. It can be seen that the hydrocarbon removal rate also decreases.

From the above (Table 3), it can be clarified that the prototype No. 1 of the present embodiment has the optimum configuration and the optimal arrangement of the metal thin plate 8.

(Eighth Embodiment) An eighth embodiment of the present invention relates to a heat-resistant insulating layer 9 provided on the surface of a thin metal plate 8 of an exhaust gas purifying catalyst device.
The present invention relates to the materials to be mixed with the enamel to make it porous and the amount of the materials to be mixed.

In the experiment, a 65 μm thick ferrite stainless steel sheet containing at least 20% by weight of chromium, 5% by weight of aluminum and 0.5% by weight of lanthanum was prepared using a 10 mm Lw, 2 mm Sw, 0.2 mm width. Into a lath net. Then, an enamel containing at least 30% by weight of a porous forming material was baked at 850 ° C. on this lath net processed product (this processed product is used unless otherwise specified).
The physical properties of the film were evaluated in terms of electrical insulation, porosity of the enamel, thermal deformation of the metal sheet when the enamel was baked, and steam resistance (exposure to an atmosphere at a temperature of 80 ° C. and a relative humidity of 95% for 100 hours). . Table 4 shows the types of porous forming materials used for the trial production and the evaluation results.

[0092]

[Table 4]

The enamel layer of prototype No. 1 in which aluminum was mixed as a porous forming material had no problem in electrical insulation, and because of its excellent porosity, there was no thermal deformation of the metal sheet when the enamel was baked, and it was peeled off. Therefore, it was optimal as a porous forming material.

Since aluminum has a melting point of 660 ° C., it is completely melted at an enamel firing temperature of 850 ° C. After the melting, a film of alumina oxide is formed on the surface. Due to the alumina oxide film formed on the surface, the enamel layer of prototype No. 1 was able to sufficiently secure electrical insulation. On the other hand, for aluminum, the value of the coefficient of thermal expansion (the value obtained by multiplying this value by 10 −6, the true value, and the unit is 1 / deg) is 24;
Its value is much larger than 11 of ferritic stainless steel and 7 to 12 of glass component contained in enamel. The magnitude of this coefficient of thermal expansion is a source for forming an enamel having excellent porosity. Since the enamel is porous, the metal sheet is prevented from being thermally deformed. In addition, despite having excellent porosity, the enamel is not separated from the metal sheet. This is because aluminum is melted at a melting point of 660 ° C. to help the enamel adhere to the metal sheet.

Next, an enamel having a different amount of aluminum as a porous forming material was experimentally manufactured, and the physical properties of the film were confirmed.
The experiment was the same as described above, except that enamels with varying amounts of aluminum were used, and the results are shown in (Table 5).

[0096]

[Table 5]

The enamel layers of prototypes Nos. 3 to 7 in which aluminum was mixed in an amount of 10 to 45% by weight and whose film properties were porous,
Since there was no problem in electrical insulation and the porosity was excellent, there was no thermal deformation of the metal sheet when the enamel was baked, and the enamel was not peeled off in appearance. Furthermore, the change in resistance was extremely small and was at a level that would not pose a problem in practical use. Also, in particular, aluminum
The above-mentioned features were extremely excellent in the enamel layer mixed with 極 め て 40% by weight. On the other hand, in the enamel layer containing less than 10% by weight of aluminum, the metal sheet was thermally deformed when enamel was baked due to poor porosity. On the other hand, if the enamel layer contains more than 45% by weight of aluminum, it is too porous and the adhesion to the metal sheet cannot be secured.

The enamel layer used in the present embodiment is composed of a glass component (silica containing approximately 9
And a small amount of sodium oxide, potassium oxide, calcium oxide, etc.) and a metal oxide pigment obtained by mixing substantially equal amounts of manganese oxide and iron oxide are mixed as the remaining components. The remaining component is a composition in which a metal oxide pigment is mixed at a ratio of 3 to 4 parts with respect to 1 part of the glass component, and this composition is generally called an enamel and has an adhesive property to stainless steel. Has the effect of increasing.

On the other hand, in the range where aluminum is changed to 10 to 45% by weight, the remaining component of the enamel layer is changed, and the metal oxide pigment is changed to 2 to 5 parts with respect to 1 part of the glass component. The same experiment was performed by changing the silica composition to 90 to 60%, changing the composition of manganese oxide in the metal oxide pigment to 80 to 30%, and further mixing zinc oxide or cobalt oxide in substantially equal amounts. However, the above features were similarly obtained. From the above, it is considered that the fact that aluminum is mixed in the enamel layer in an amount of 10 to 45% by weight is the main cause of this excellent feature.

The material of the thin metal plate is not particularly limited as long as stainless steel is used. Needless to say, the same effect can be obtained with stainless steel.

(Embodiment 9) Embodiment 9 of the present invention is directed to a heat-resistant insulating layer 9 provided on the surface of a thin metal plate 8 of an exhaust gas purifying catalyst device.
It relates to the amount of titanium oxide mixed with the enamel to improve the steam resistance.

The experiment was the same as in Example 8 except that enamels were used in which the mixing amount of aluminum and titanium oxide was changed. The physical properties of the film were evaluated in terms of the porosity of the enamel, the degree of thermal deformation of the metal sheet when the enamel was baked, and the steam resistance (exposure to an atmosphere at a temperature of 80 ° C. and a relative humidity of 95% for 100 hours). Table 6 shows the kinds of mixed amounts of aluminum and titanium oxide used in the trial production and the evaluation results.

[0103]

[Table 6]

The enamel layer in which 10 to 25% by weight of titanium oxide is further mixed with a mixture of 10 to 45% by weight of aluminum has excellent porosity, has no thermal deformation of the metal sheet when the enamel is baked, and has a high vapor density. It has the characteristic that the adhesiveness when it is exposed for a long time is extremely excellent. Further, the change in the resistance was extremely small and was at a level that would not cause a problem in practical use. In particular, 30 to 40% by weight of aluminum
And the enamel layer containing 15 to 20% by weight of titanium oxide are particularly excellent in the above characteristics. On the other hand, if the titanium oxide is less than 15% by weight of an enamel, the steam resistance is not improved as expected, and if the titanium oxide is more than 25% by weight, the thermal deformation of the metal sheet tends to decrease. The amount of titanium oxide to be produced was not preferable.

The enamel used in this example is composed of a composition obtained by mixing a metal oxide pigment at a ratio of 2 to 3 parts with respect to 1 part of a glass component, in addition to the above amounts of aluminum and titanium oxide. As a mixture to help weld the enamel. The glass component is 90% silica and the remainder is oxides of sodium, potassium, calcium and magnesium. The metal oxide-based pigment is obtained by mixing substantially equal amounts of manganese oxide and iron oxide.

On the other hand, in the range of 10 to 45% by weight of aluminum and 10 to 25% by weight of titanium oxide, the remaining component of the enamel layer was added, and 1 to 4 parts of the metal oxide pigment was added to 1 part of the glass component. Or the composition of silica in the glass component is changed to 90 to 60%, the composition of manganese oxide in the metal oxide pigment is changed to 80 to 30%, and zinc oxide and cobalt oxide are added in approximately equal amounts. Even when the same experiment was performed with further mixing, excellent adhesion was similarly obtained.

As is apparent from the above, 10 to 45% by weight of aluminum and 10 to 2% of titanium oxide were contained in the enamel.
5% by weight is considered to be the main cause of this excellent adhesion.

The material of the metal thin plate is not particularly limited as long as stainless steel is used. Needless to say, the same effect can be obtained with stainless steel.

(Embodiment 10) Embodiment 10 of the present invention relates to the material composition of the odor decomposition catalyst 10 of the exhaust gas purifying catalyst device, using FIGS. 2 and 3 used in the description of Embodiment 2. Portions having the same function and effect as those of the first to sixth embodiments are denoted by the same reference numerals, detailed description thereof will be omitted, and different portions will be mainly described.

The odor decomposition catalyst 10 is processed into a lath network,
On the surface of a stainless steel thin plate 8 processed into a corrugated shape, enamel with a mixed amount of aluminum was changed at 850 ° C.
Baking to form a heat-resistant insulating layer 9, and then a sol of aluminum hydroxide is adhered to the surface of the heat-resistant insulating layer 9 to form
Calcination at 0 ° C. to form an alumina carrier layer. Finally, noble metals such as platinum and palladium are supported on this carrier layer and
Baking to obtain an odor decomposition catalyst. And
The metal sheet 8 provided with the odor decomposition catalyst 10 is housed in the gas passage cavity 4 of the housing 5 in a two-layer structure substantially perpendicularly to the gas passage direction to form an exhaust gas purifying catalyst device. Attached to evaluate hydrocarbon removal rate. In addition, in a high-temperature and high-humidity environment (temperature 80% and relative humidity 95%)
The adhesion of the heat-resistant insulating layer and the odor decomposition catalyst to the metal sheet when left for 00 hours was evaluated by a tape peeling method. The results are shown in Table 7.

[0111]

[Table 7]

An odor decomposition catalyst in which a sol of aluminum hydroxide is adhered to an enamel layer in which aluminum is mixed in an amount of 10 to 45% by weight and calcined to form an alumina carrier layer and carry a noble metal such as platinum or palladium has excellent purification characteristics. It shows adhesion. In addition, it exhibited particularly excellent adhesion to an enamel layer containing 20 to 40% by weight of aluminum. Aluminum has a melting point of 660 ° C. and melts when the enamel is fired, and its surface changes to alumina having a large specific surface,
Thermal expansion coefficient is other enamel component or stainless steel sheet,
Furthermore, it has a remarkably large property with respect to the alumina carrier layer. Therefore, the enamel in which aluminum is mixed in an amount of 10 to 45% by weight becomes a porous body having alumina exposed on the surface and is firmly adhered to the metal sheet, and the sol of aluminum hydroxide adheres to the surface-exposed alumina. The alumina carrier layer obtained by sintering is also firmly adhered to because it is easy to perform.
On the other hand, in the case of an enamel layer containing less than 10% by weight of aluminum, the adhesion to the carrier layer could not be ensured because the enamel layer had a small amount of exposed alumina. On the other hand, if the enamel layer contained more than 45% by weight of aluminum, the layer was too porous and the adhesion to the metal sheet was not ensured.

The enamel used in the above examples was prepared by adding, in addition to the above amount of aluminum, one part of a glass component (about 90% of silica and the remaining oxides of sodium, potassium, calcium and magnesium). A composition in which 3 to 4 parts of a metal oxide pigment (manganese oxide and iron oxide are mixed in substantially equal amounts) is mixed as the remaining component. Therefore,
As described above, experiments were performed by changing the mixing ratio of the glass component and the metal oxide pigment and the composition thereof, but the above effects were similarly obtained.

Next, the same experiment was performed using an enamel further mixed with titanium oxide, and the results are shown in (Table 8).

[0115]

[Table 8]

In this experiment, aluminum was added to a composition obtained by mixing 2 to 3 parts of a metal oxide pigment obtained by mixing substantially equal amounts of manganese oxide and iron oxide and 1 part of a glass component.
5% by weight and titanium oxide were mixed at 10 to 25% by weight and mixed to produce an enamel, which was subjected to the same experiment as described above.

It can be seen that an enamel obtained by mixing 10 to 45% by weight of titanium oxide with a mixture of 10 to 45% by weight of aluminum exhibits excellent purification characteristics and more excellent adhesion. Further, as described above, the experiment was conducted by changing the mixing ratio of the glass component and the metal oxide pigment and the composition thereof, and the above effects were similarly obtained.

As described above, even if the material composition and the composition of the metal oxide pigment and the glass component are changed, aluminum remains 1%.
If the enamel is mixed at 0 to 45% by weight, there is no problem in the adhesiveness to the metal sheet and the odor decomposition catalyst. Probable cause.

On the other hand, when the sol composition of aluminum hydroxide used as the carrier layer was tested, the adhesion between the enamel and the carrier layer was not particularly changed if the content of the other compound was within 30% by weight, preferably within 15% by weight. . Therefore, when 2 to 30% by weight, preferably 2 to 15% by weight, of cerium oxide having excellent oxygen adsorbing ability is mixed with the sol, a characteristic in which the purification property is improved while maintaining the adhesion to the enamel was obtained.
When barium oxide, calcium oxide, and magnesium oxide, which have excellent gasification ability for cooking oil smoke, are mixed with the sol in an amount of 1 to 30% by weight, preferably 1 to 10% by weight, it is difficult to maintain the adhesion to the enamel and the purification properties. There was a characteristic that the odor could be reduced. In particular, barium oxide was excellent in this characteristic.

The material of the thin metal plate is not particularly limited as long as stainless steel is used. Needless to say, the same effect can be obtained with stainless steel.

As described above, the carrier layer obtained by adhering the sol containing aluminum hydroxide as a main component to the surface of the heat-resistant insulating layer and calcining it, and at least one of platinum and palladium carried on the carrier layer, or It forms an odor decomposition catalyst composed of a noble metal having both of them, and can exhibit excellent purification characteristics and adhesion. This is because the carrier layer penetrates into the voids of the enamel layer that has become porous due to the mixing of aluminum and adheres firmly, and at least one of the highly active platinum and palladium, or both noble metals, form this porous material. This is because it is firmly attached to a suitable carrier layer.

The sol of aluminum hydroxide may be referred to as a sol of aluminum oxide hydrate or an alumina sol, but the name is not particularly limited.

(Embodiment 11) In Embodiment 11 of the present invention, a non-energized ventilation plate having an odor decomposition catalyst provided substantially vertically in a gas passage cavity of a housing downstream of a metal sheet with an odor decomposition catalyst is provided. 2 and 3 used in the description of the second embodiment, the same reference numerals are given to portions having the same functions and effects as those of the first to sixth embodiments. Therefore, detailed description is omitted, and different points will be mainly described.

Reference numeral 28 denotes a non-conductive ventilation plate having a plurality of holes 29 formed by lath netting a stainless steel plate and having an odor decomposition catalyst attached to the surface thereof. 12 grooves 30a provided on the gas passage cavity 4 side
And the groove 30b is fitted so as not to leak gas, and is arranged substantially perpendicular to the gas passage direction.

In the above example, the exhaust gas purifying catalyst device was attached to the exhaust port of an electric oven, and the effect of the experiment was carried out on two items, ie, the leakage of cooking gas and the hydrocarbon removal rate (Table 9). ).

[0126]

[Table 9]

The prototype No. 1 is an exhaust gas purifying catalyst device without the ventilation plate 28, in which only the metal sheet 8 with the odor decomposition catalyst 10 is provided in a one-layer structure at the inlet side in the gas passage cavity of the housing 5. I have. The prototype No. 2 is an exhaust gas purifying catalyst device in which the ventilation plate 28 of this embodiment is provided substantially vertically in the gas passage cavity 4 of the housing 5 on the downstream side of the thin metal plate 8 with the odor decomposition catalyst 10. . In each of the prototypes, the metal sheet 8 with an odor decomposition catalyst which generates heat when energized is disposed on the upstream side of the ventilation plate. The thin metal plate 8 with the odor decomposition catalyst 10 is formed by laminating a heat-resistant insulating layer made of an enamel and a sol of aluminum hydroxide on the surface of a stainless steel foil processed into a lath net shape and further processed into a corrugated shape, followed by firing. And an odor decomposition catalyst composed of a support layer of alumina and a noble metal of platinum and palladium supported on the support layer. And 50W
Is maintained at 400.degree.

It can be seen that, when the ventilation plate 28 is disposed on the downstream side of the thin metal plate 8, the decomposition rate of the odor component is further increased. This is because the passage speed of the cooking gas was reduced by the ventilation plate 28, and the reaction time of the thin metal plate 8 with the odor decomposition catalyst 10 was prolonged, and there was no leakage of the cooking gas.

Further, regarding the effect of the odor decomposition catalyst of the ventilation plate 28, an experiment was carried out in the same manner as described above, with the exhaust gas purifying catalyst device attached to an electric oven, and the leakage of the cooking gas and the second hydrocarbon removal rate. The results are shown in (Table 10).

[0130]

[Table 10]

The prototype No. 1 is an exhaust gas purifying catalyst device having only a stainless steel ventilation plate which has been processed into a lath net shape and has a wavy shape without an odor decomposition catalyst provided on the surface thereof. At the entrance side in the passage cavity, only the metal sheet 8 with the odor decomposition catalyst 10 is provided in a one-layer structure. The prototype No. 2 is such that the ventilation plate 28 of this embodiment is provided substantially vertically in the gas passage cavity 4 of the housing 5 downstream of the thin metal plate 8 with the odor decomposition catalyst 10. Then, the ventilation plate 28 with the odor decomposition catalyst is attached with an oxide film formed by heat treatment and a sol of aluminum hydroxide on the surface of a stainless steel foil processed into a lath net shape and further processed into a corrugated shape, and baked. And an odor decomposition catalyst composed of a support layer of alumina and a noble metal of platinum and palladium supported on the support layer. In each of the prototypes, the metal thin plate 8 is arranged on the upstream side of the ventilation plate, and electricity is supplied to the prototype, and no electricity is supplied to the ventilation plate.

It can be seen that the formation of the odor decomposition catalyst on the ventilation plate 28 further increases the decomposition rate of the odor components. This is because the metal sheet 8 with the odor decomposition catalyst 10 arranged on the upstream side in the gas passage cavity 4 of the housing 5 is energized by electricity.
The temperature is raised to 0 ° C., and this heat is applied to the ventilation plate 28 disposed on the downstream side.
And the temperature of the ventilation plate 28 rises to 380 ° C., and the effect of the catalyst is exhibited. In addition, the odor decomposition catalyst is formed by applying a sol of aluminum hydroxide to the surface of an oxide film formed by heat-treating a stainless steel foil and baking to form a carrier layer of alumina, and further forming a carrier layer of platinum and palladium on the carrier layer. Since it is obtained by a manufacturing method supporting a noble metal, it has excellent adhesion.

On the other hand, since the ventilation plate 28 is not energized, electric power is concentrated only on the metal sheet 8, and as a result, the metal sheet 8 is maintained at a high temperature, and the decomposition characteristics of the odor decomposition catalyst formed on the surface thereof are further improved.

[0134]

As is apparent from the above description, the heating cooker according to the present invention has the following effects.

According to the first aspect of the present invention, there is provided a heat-resistant insulating casing having a gas passage cavity therein, and a water-repellent heat-resistant insulating film provided on the inlet side surface of the gas passage cavity. A metal sheet provided in the gas passage cavity downstream of the water-repellent heat-resistant insulating film and having a plurality of holes and generating heat by energization; a heat-resistant insulating layer formed on the surface of the metal sheet; With a odor decomposition catalyst formed on the surface of the layer, a water-repellent heat-resistant insulating film is provided on the inlet side surface in the gas passage cavity of the housing, and the odor decomposition catalyst is formed from the water-repellent heat-resistant insulating film. Since it is provided in the downstream gas passage cavity, the water repellent and heat-insulating coating of the water-repellent and heat-insulating coating on the inlet side in the gas passage cavity allows the exhaust gas generation device to be caused by the moisture attached to the metal sheet. Electrical continuity is interrupted and metal Current flowing in the plate can be prevented from flowing to the exhaust gas generator device. Further, since the odor decomposition catalyst is provided on the heat-generating thin metal plate via the heat-resistant insulating layer, the heating of the catalyst can be performed with low power and the temperature can be raised in a short time.

According to a second aspect of the present invention, a casing having a gas passage cavity is formed by joining a plurality of divided casings having heat insulation and heat resistance, and is provided on an inner surface of the divided casing. A groove is provided, and a metal sheet having an odor decomposition catalyst on its surface is fitted into the groove, and the metal sheet is disposed substantially perpendicular to the gas passage direction. Since it is provided substantially vertically inside, the exhaust gas flowing in the gas passage cavity can be efficiently brought into contact with the odor decomposition catalyst without leaking to increase the odor component decomposition rate. Also, the housing can be assembled simply by fitting a thin metal plate into the groove of the divided housing and joining the divided housings, so that the housing can be easily assembled. In addition, if the housing is formed of a heat-resistant heat insulating material such as ceramic, the heat insulating effect can be enhanced, the temperature of the odor decomposition catalyst can be increased, and the decomposition rate of odor components can be further increased. further,
Since the metal sheet is disposed substantially perpendicular to the gas passage direction in the gas passage cavity, exhaust gas can effectively pass through the holes of the metal sheet to reduce pressure loss, and contact with the odor decomposition catalyst can be prevented. As a result, the decomposition rate of the odor component can be increased.

The invention according to claim 3 is the same as the invention according to claim 2.
In the above description, a water-repellent heat-resistant insulating film is provided on an inlet-side joining surface and an inlet-side front end surface of the divided housings forming the gas passage cavity, and the water-repellent action of the water-repellent heat-resistant insulating film is provided. In addition, even when a minute gap is formed on the joint surface of the divided housing due to the insulating action, the electrical conduction through the dew condensation water leaking therefrom is cut off, and the current of the thin metal plate can be prevented from flowing to the exhaust gas generation device side.

The invention described in claim 4 is the same as the claim 2
In the description, a water-repellent heat-resistant insulating film is provided on the outer peripheral surface on the entrance side of the divided housing forming the gas passage cavity. Thus, even when moisture adheres to the outer peripheral surface of the housing, the electrical continuity between the thin metal plate and the exhaust gas generator via the moisture can be cut off, and the current of the thin metal plate can be prevented from flowing to the exhaust gas generator.

Further, in the invention according to claim 5, the water-repellent heat-resistant insulating film is formed of a film mainly composed of a fluorine resin. It is possible to further prevent the gas from flowing to the exhaust gas generator and to maintain the performance for a long time without deterioration even when exposed to high temperature exhaust gas.

Further, the invention according to claim 6 is one in which the joint portion of the plurality of divided casings constituting the casing is fixed by sandwiching from outside from the outside by the fixing member, so that the casing of the exhaust gas purifying catalyst device can be simplified. Can be assembled and securely fixed.

Further, in the invention according to claim 7, the metal thin plate is formed by processing a stainless thin plate into a lath net shape and further processing it into a corrugated shape. Since the heat capacity and weight% can be reduced, and the hole opening ratio can be increased, the temperature can be raised quickly with less power consumption, the corrosion resistance is excellent, and the heat generation area per unit volume can be increased, resulting in high heat generation. Temperature.

The invention according to claim 8 is the invention in which the metal sheet is a stainless steel sheet processed into a lath mesh, and the heat-resistant insulating layer is formed of an enamel containing at least 10 to 45% by weight of aluminum. Becomes a porous heat-resistant insulating layer, which can prevent heat deformation and peeling of the enamel when the enamel is baked.

The invention according to claim 9 is a stainless steel sheet obtained by processing a thin metal sheet into a lath mesh, wherein the heat-resistant insulating layer is 10 to 45% by weight of aluminum and 10% by weight of titanium oxide.
The enamel is a porous heat-resistant insulating layer having excellent heat- and water-resistance, and the heat-deformation of the metal sheet when the enamel is baked even when exposed to exhaust gas for a long time. An enamel can be prevented from peeling.

Further, according to the present invention, there is provided a carrier layer obtained by adhering a sol containing aluminum hydroxide as a main component to the surface of the heat-resistant insulating layer according to claim 8 or 9, and firing the carrier layer. An odor decomposition catalyst comprising a noble metal having at least one or both of platinum and palladium supported on the layer is formed, and can exhibit excellent purification characteristics and adhesion. Further, the invention according to claim 11 is characterized in that a non-energized ventilation plate made of stainless steel having a plurality of holes is provided substantially perpendicular to the gas passage direction in the gas passage cavity of the casing downstream of the thin metal plate, An oxide film formed by heat treatment on the surface of the ventilation plate, a carrier layer obtained by attaching a sol containing aluminum hydroxide as a main component to the oxide film, and at least one of platinum and palladium supported on the carrier layer. Or a odor decomposition catalyst comprising a noble metal having both or
The ventilation plate reduces the speed at which exhaust gas passes through the gas passage cavity, increasing the reaction time of the metal sheet with the odor decomposition catalyst, increasing the odor decomposition rate, and reacting with the catalyst by the odor decomposition catalyst of the ventilation plate. The number of times increases and the decomposition rate of the odorous component can be further increased, and the adhesiveness is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an exhaust gas purifying catalyst device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a main part in Examples 2 to 11 of the apparatus.

FIG. 3 is a longitudinal sectional view of the apparatus in Examples 2 to 11;

FIG. 4 is a perspective view of a main part of a conventional exhaust gas purifying catalyst device.

[Description of Signs] 4 Cavity for gas passage 5 Housing 6, 6a, 6b Water-repellent heat-resistant insulating film 7, 29 holes 8 Metal thin plate 9 Heat-resistant insulating layer 10 Odor decomposition catalyst 11 Housing bottom (divided housing) 12 Housing Body cover (divided housing) 13a, 13b Groove 16a, 16b Inlet-side joining surface 17a, 17b Inlet-side front end surface 18a, 18b Inlet-side outer peripheral surface 24a, 24b Fixing member 28 Ventilation plate

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Tadashi Suzuki 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 4D048 AA17 AA18 AA22 AB01 AB03 BA03X BA07X BA30X BA31X BB02 CC32 CC38 CC43 4G069 AA01 AA03 AA08 BA01A BA01B BA01C BA04A BA04B BA04C BB02A BB02B BC72A BC72B BC75A BC75 CA18 CA17 CA15 CA17 CA17

Claims (11)

[Claims] 1. A heat-resistant insulating housing having a gas passage cavity therein, a water-repellent heat-resistant insulating film provided on an inlet side surface in the gas passage cavity, and the water-repellent heat-resistant insulating film. A metal thin plate which is provided in the gas passage cavity downstream and has a plurality of holes and generates heat by energization, a heat-resistant insulating layer formed on the surface of the metal thin plate, and an odor decomposition catalyst formed on the surface of the heat-resistant insulating layer. Exhaust gas purification catalyst device equipped. 2. A housing is formed by joining a plurality of divided housings having heat and heat insulation, and a groove is provided on an inner surface of the divided housing, and a metal sheet is fitted into the groove to allow gas to pass therethrough. The exhaust gas purifying catalyst device according to claim 1, wherein the catalytic converter is disposed substantially perpendicular to the direction. 3. The exhaust gas purifying catalyst device according to claim 2, wherein a water-repellent heat-resistant insulating film is provided on an inlet-side joining surface and an inlet-side front end surface of the divided casings forming the gas passage cavity. 4. The exhaust gas purifying catalyst device according to claim 2, wherein a water-repellent heat-resistant insulating film is provided on the outer peripheral surface on the inlet side of the divided housing forming the gas passage cavity. 5. The exhaust gas purifying catalyst device according to claim 1, wherein the water-repellent heat-resistant insulating film is formed of a film containing a fluorine resin as a main component. 6. The exhaust gas purifying catalyst device according to claim 2, wherein the fixing member sandwiches and fixes a joint portion of the plurality of divided housings forming the housing from outside. 7. The exhaust gas purifying catalyst device according to claim 1, wherein the metal sheet is formed by processing a stainless steel sheet into a lath net shape and also into a corrugated shape. 8. The thin metal plate is a stainless steel plate processed into a lath mesh, and the heat-resistant insulating layer is made of aluminum at least 10 times.
The exhaust gas purifying catalyst device according to claim 1, wherein each of the catalyst devices is formed of an enamel containing up to 45% by weight. 9. The thin metal plate is a stainless steel plate processed into a lath mesh, and the heat-resistant insulating layer is formed of an enamel containing at least 10 to 45% by weight of aluminum and 10 to 25% by weight of titanium oxide. Exhaust gas purification catalyst device. 10. The odor decomposition catalyst includes a carrier layer to which a sol containing aluminum hydroxide as a main component is adhered and calcined, and at least one or both of platinum and palladium carried on the carrier layer. The exhaust gas purifying catalyst device according to claim 8, wherein the catalytic converter is formed of a noble metal. 11. A non-conducting ventilation plate made of stainless steel having a plurality of holes and provided substantially perpendicular to the gas passage direction in the gas passage cavity of the housing downstream of the thin metal plate, and heat-treating the surface of the ventilation plate. An oxide film formed by the above, a carrier layer obtained by attaching a sol containing aluminum hydroxide as a main component to the oxide film, and at least one of platinum and palladium supported on the carrier layer, or both. The exhaust gas purifying catalyst device according to claim 1, wherein an odor decomposition catalyst composed of a noble metal is formed.