JPH04169716A - Heating cooker - Google Patents

Abstract

PURPOSE:To improve the efficiency of deodorization markedly by attaching a barrier plate for blocking a flow of air to the peripheral part of an oxidation- deodorization catalyst having a three-dimentional porous material as a carrier. CONSTITUTION:In an exhaust duct 12 forming a flue, heaters 9 and a catalyst 11 are set in a setup to draw air from the cooking chamber into the exhaust duct 12 through an exhaust opening 13 and heat the air by the heaters 9 and send it to the catalyst 11. In the view of the catalyst 11 in place as seen from a lower inside part of the exhaust duct, dotted lines represent the positions of the heaters 9 in place; a barrier plate 10 is set in place in such a manner as to enclose the catalyst 11 at all points of its periphery. The attachment of the barrier plate 10 around the catalyst 11 brings about a considerable decrease in the amount of air (air velocity) passing along the periphery and such a reduction in the leakage per unit area of acetaldehyde at the periphery that an improvement in the overall efficiency of deodorization results.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a heating cooking apparatus such as a household oven grill range for cooking food, and particularly relates to its deodorizing function.

(Prior Art) Generally, oven grill ranges and the like generate odor and smoke during cooking. Modern homes are often airtight, and the odors and smoke generated during cooking are extremely unpleasant for the occupants, and can sometimes stick to the walls and furniture of the room. . As a method to remove this odor, the air fan of the oven grill range is used to force the odor out of the exhaust duct, bringing in fresh air into the cooking chamber and eliminating the odor inside the oven. There is a way. The odor is oxidized and decomposed by a heated deodorizing catalyst placed in the exhaust duct, and the odorless odor is released to the outside.

The source of the odor is gas and mist components generated from the food being heated inside the oven and oil and meat juices adhering to the inner walls, but by introducing fresh air, the odor concentration decreases exponentially. I will do it.

Is this deodorizing catalyst made by supporting noble metals such as platinum or palladium on ceramic honeycomb or silica paper corrugate? Generally, it is made by depositing metals such as nickel, chromium, aluminum, etc. on the cell walls of an organic foam, such as urethane foam, and burning off the organic part in an oxygen-free condition.Created using the second support. The characteristics of this catalyst are that it has high strength, and that turbulence is easy to occur, so the contact between the catalyst and gas can be made efficiently and the catalyst can be made thin.Because it is a metal form,
This method is advantageous in terms of cost, as it can first create a large catalyst and then cut it to the required size. In particular, plate-shaped catalysts (about 10 mm thick) can be cut by press cutting.
It has the advantage of being able to be shaped into any size. This was advantageous because it was suitable for mass production and could provide a low-cost catalyst.

In this way, in a method in which a catalyst is placed in a duct and air is passed through the catalyst to deodorize, the catalyst as a whole does not perform the deodorizing function in the same way in all respects. For example, when looking at the gas throughput of a catalyst, the amount of air passing through the catalyst in a plane perpendicular to the axis of flow varies depending on the location. Generally, there is more in the center, and the amount decreases towards the periphery. In addition, in methods other than methods in which the catalyst is heated from outside around the catalyst, the temperature of the catalyst generally decreases toward the surroundings. Therefore, the deodorizing efficiency in the surrounding area is inferior to that in the center. When measured using an actual catalyst, the deodorizing efficiency was sometimes about 100 times worse than the median. Especially,
When the peripheral part of a catalyst with such metal foam as a support is machined, the catalyst is not attached to the outer peripheral part of the catalyst and the support is exposed, which causes odor leakage from the surrounding area. There was something quite large.

In addition, when such a catalyst is heated with multiple lot-shaped heaters, such as a heater, a ceramic heater, or a glass tube heater, the part closest to the heater becomes linear;
This is where the temperature is the highest, and the farther you go from there, the lower the temperature.

The temperature of the area on the center line of the two parallel heater shafts, which corresponds to the periphery of the catalyst, is low, and the odor decomposition efficiency here is poor, causing odor leakage.

(Problem to be solved by the invention) In this way, in conventional oven grill ranges in which a deodorizing catalyst is installed in the exhaust duct, the odor leaks from the peripheral part of the installed deodorizing catalyst, and the overall deodorizing and decomposition efficiency is poor. It goes down. Therefore, to improve deodorizing performance,
There was a limit. This not only causes the odor to be emitted into the room, causing discomfort to the user, but also causes the odor to stick to the walls and furniture of the room.

Therefore, an object of the present invention is to provide a cooking device that can reduce the amount of odor leaking from the peripheral portion of the oxidation deodorization catalyst and improve the deodorization efficiency.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention installs a heater that heats the food to be cooked in the cooking chamber, and installs a heater in the exhaust path that exhausts the air in the cooking chamber. The gist is that an oxidative deodorizing catalyst using a three-dimensional porous body as a carrier is installed, and a barrier body for blocking air flow is attached to the peripheral portion of the oxidizing deodorizing catalyst.

(Function) Due to the processing and manufacturing process, the oxidation deodorizing catalyst that uses a three-dimensional porous material as a support tends to have a structure in which the support is exposed at the peripheral part and no catalyst is attached, and the peripheral part tends to be in the exhaust passage. Due to the design, a clearance is likely to occur between it and the wall surface, etc. Furthermore, during use, the heating temperature of the peripheral portion tends to be low. For these reasons, the deodorizing and decomposing performance of the peripheral portion deteriorates and odor tends to leak. In contrast, in this invention,
By attaching a barrier body that blocks the flow of air to the peripheral portion of the oxidation deodorizing catalyst, this can be suppressed and the deodorizing efficiency can be improved.

(Example) Hereinafter, two embodiments of the present invention will be explained based on the drawings. This embodiment is applied to a microwave oven.

1 to 6 are diagrams showing a first embodiment of the present invention.

In Figures 1 and 2, 1 is the main cabinet, 2
is the oven inner box that constitutes the cooking chamber, 3 is the door of the cooking chamber, 4
is a glass barrier, and 5 is a handle.

On the back side of the cooking chamber, there is a sirocco fan 6 that circulates hot air in the cooking chamber (inside the oven) when the oven function is activated.
, a motor 7 for driving a sirocco fan, and an oven heater 8 are provided. Reference numeral 9 denotes a heater for heating the catalyst, which is made of a spiral nichrome wire placed in a ceramic tube, and has a capacity of about 1.2 kW.

The oxidation deodorizing catalyst (hereinafter simply referred to as catalyst) 11 is formed by adhering PT onto a three-dimensional porous carrier made of Ni--Cr foam with a thickness of about 10 mm.

Reference numeral 12 denotes an exhaust duct serving as an exhaust path, in which a heater 9 and a catalyst 11 are incorporated. Air inside the refrigerator is taken into the exhaust duct 12 through the exhaust port 13, heated by the heater 9, and guided to the catalyst 11. Reference numeral 14 represents the food to be cooked, and reference numeral 15 represents an air blowing fan, which blows air into the refrigerator from an air intake duct 16. The air supply fan 15 also has a function of cooling a magnetron (not shown) located at the entrance of the air intake duct 16. The exhaust port 13 is made of metal mesh or punched metal that does not leak microwaves to the outside.

FIG. 3 shows the structure of the attachment of the exhaust duct 2 to the oven inner box 2. That is, a metal plate bent into a U-shaped cross section is fixed to the outer wall of the oven inner box 2 so as to be pressed against it from the left side in the figure. The catalyst 1] and the heater 9 are installed at a position that corresponds to the back side of the oven inner box 2. The air coming out of the exhaust port 13 is transferred to this exhaust duct 12.
and is guided to the catalyst 11.

FIG. 4 shows the mounting structure of the catalyst 11 in the exhaust duct 12 together with a comparative example. Figure (A) shows the mounting structure of this embodiment, and Figure (B) shows the mounting structure of the comparative example.

The catalyst 1 is positioned and fixed by a fixing claw 17 made by cutting out a part of the exhaust duct 12.

The heater 9 is fixed through the exhaust duct from the upper part to the lower part,
This is to heat the catalyst 11. In addition to such a structure, in this embodiment shown in FIG.
A barrier plate 10 as a barrier made of metal is attached to the peripheral edge of the exhaust duct 12 so as to block the flow of air (from left to right in the figure). In contrast, Fig. 4 (
In the comparative example shown in B), no barrier plate was attached.

Next, the operation of the heating cooking device configured as described above will be explained.
This will be explained in comparison with the effect of a comparative example.

FIG. 5 shows the results of measuring the deodorizing effect. Same figure (A)
shows this example, and FIG. 3B shows a comparative example. The measurement method is to first make the inside of the oven almost airtight, and then add zero acetaldehyde 1% aqueous solution to the inside of the oven.
．． Exhaust duct 12 when 5ml/min continuous injection
The concentration of acetaldehyde and air flow rate at each part of the catalyst inside were measured, and the leakage amount of acetaldehyde per unit area was calculated from these two values.

(a) in FIGS. 5A and 5B is a front view seen from inside the exhaust duct where the catalyst 11 is installed, and the dotted line indicates the installation position of the heater 9. The barrier plate 10 is attached so as to surround the entire periphery of the catalyst 11. Lower (b)
, (C) The two figures show the concentration of acetaldehyde, the air flow rate, and
and the amount of leakage of acetaldehyde per unit area calculated from these two values.

First, in the comparative example shown in FIG. 1(B), a clearance of approximately 0.5+n+a is required around the catalyst 11 due to design and assembly.
Therefore, the amount of air flowing from here is large. Outside this perspective, the wind speed has a peak in the center. Also heater 9
At the position, the airflow is obstructed and the wind speed is reduced. In addition, the concentration of acetaldehyde at each position is as follows:
1. Low temperature and catalyst] 1. Platinum is attached to a metallic three-dimensional porous support and cut and shaped, so there is no catalyst attached to the outer peripheral surface, and the support is Because the body is exposed, the decomposition efficiency of acetaldehyde from the surrounding area is low, and the concentration is high. The decomposition efficiency of acetaldehyde is the best immediately below the heaters 9 because the temperature is high, and the decomposition efficiency is slightly lower between the two heaters 9 because the temperature of the catalyst 11 is slightly lower. The product of these two values is the amount of acetaldehyde leakage per unit area. As a result, it can be seen that in the comparative example, the amount of leakage from the periphery is extremely large.

On the other hand, in the second embodiment shown in FIG. 3A, a barrier plate 10 is attached around the catalyst 11. Therefore, it can be seen that the amount of air flowing (wind speed) in the surrounding area is significantly lower than that of the comparative example. Therefore, by reducing the amount of acetaldehyde leaked per unit area at the peripheral edge, it is possible to increase the deodorizing efficiency as a whole. That is, the overall deodorizing efficiency was 58% in the comparative example, but it was able to be increased to 88% in this example.

FIG. 6 shows the temperature distribution of the catalyst. The same figure (A) shows the thing of this example, and the same figure (B) shows the thing of a comparative example. According to this, as mentioned above, the temperature is highest near the heater of the catalyst 11, and it can be seen that the temperature is lowest in the vicinity, especially near the middle of the heater. Further, it can be seen that in this example, another effect of the barrier plate 10 is the heating effect of the catalyst 11. In other words, a metallic barrier plate 1 with high thermal conductivity
It can be seen that by using 0, there is an effect of heating the catalyst 11 by heat transfer from the surroundings.

Next, FIG. 7 shows a structure for mounting a barrier plate, etc. in a second embodiment of the present invention. In this embodiment, the barrier plate 20 has a central portion between the center lines of the two rod-shaped heaters that heat the catalyst 11, and the peripheral portion of the catalyst is larger than the other portions. As mentioned above, the temperature in this area is low, and the decomposition efficiency here is somewhat low. Therefore, by providing the barrier plate 20 having such a structure, the deodorizing efficiency can be further improved. In this example, it was found that the deodorizing efficiency of the catalyst 11 as a whole was improved to 95%.

Note that if the area of the barrier plate 20 that covers the catalyst 11 is made larger than necessary, the effectively used area of the catalyst 11 will be reduced, and the amount of ventilation in the open portion of the catalyst 11 will be increased, which will reduce the deodorizing efficiency. This is not desirable as it may lead to a decrease in The area covering the catalyst 11 needs to be determined by looking at the actual amount of air flow and temperature distribution.

FIG. 8 shows a structure for mounting barrier plates, etc. in a third embodiment of the present invention. In this embodiment, the barrier plate 30 wraps the entire catalyst 11, and the barrier plate 30 has a border 31 on its entire surface.

By doing so, the barrier plate 30 can be easily attached.

FIG. 9 shows a structure for mounting barrier plates, etc. in a fourth embodiment of the present invention. In this embodiment, L of the barrier plate 40 is
A self-tapping screw hole is made in the curved part of the mold, and the catalyst is fixed by screws 18 between this and the wall of the exhaust duct 12, and the barrier plate 40 also serves to fix the position of the catalyst 11. .

FIG. 10 shows the structure of a barrier plate in a fifth embodiment of the present invention. This is a portion of the L-shaped bent portion of the barrier plate 50 in which a notch 19 is provided so that part of the two upper and lower sides are aligned with the peripheral wall surface of the heater 9. By doing so, the distance between the catalyst 11 and the heater 9 can be shortened or they can be brought into contact with each other, and the catalyst 11 can be heated efficiently.

FIG. 11 shows a structure for mounting barrier plates, etc. in a sixth embodiment of the present invention. In this embodiment, the installation is a structure when the area of the catalyst 11 is smaller than the cross-sectional area of the exhaust duct 12. The catalyst 11 is fixed to the barrier plate 60 by a fixing fitting 21. In this case as well, the airflow flowing through the peripheral portion of the catalyst 11 where the deodorizing efficiency is poor can be blocked by the barrier plate 60, and the deodorizing performance can be improved.

[Effects of the Invention] As explained above, according to the present invention, a barrier plate for blocking air flow is attached to the peripheral portion of the oxidation deodorization catalyst using a three-dimensional porous body as a carrier, so that the deodorization and decomposition performance is improved. It is possible to suppress the leakage of odor from the peripheral portion, which is prone to deterioration, and it is possible to significantly improve the deodorizing efficiency.

[Brief explanation of the drawing]

Figures 1 to 6 show the first heating cooking device according to the present invention.
Fig. 1 is a perspective view showing the external appearance, and Fig. 2 is a perspective view showing an example.
The figure is a sectional view taken along the line ■-■ in Figure 1, Figure 3 is an exploded perspective view showing the structure of the installation of exhaust ducts, etc., and Figure 4 is the structure of the installation of catalysts etc. in the exhaust duct, along with a comparative example. A perspective view, FIG. 5 is a diagram showing the measurement results of deodorizing performance along with a comparative example, FIG. 6 is a diagram showing the temperature distribution on the catalyst surface along with a comparative example, and FIG. 7 is a diagram showing the barrier plate etc. in the second embodiment of the present invention. 8 is a side sectional view showing the structure of the mounting of the barrier plate in the third embodiment of the present invention, and FIG. 9 is a front view showing the structure of the barrier plate in the fourth embodiment of the present invention. 10 is a perspective view showing the structure of the barrier plate in the fifth embodiment of the present invention, and FIG. 11 is a side sectional view showing the structure of the barrier plate in the sixth embodiment of the present invention. FIG. 2. Oven inner box constituting the cooking chamber, 8: Oven heater, 9: Heater for catalyst heating, 10.20.30.40.50.6o, barrier plate (barrier body), 1. Oxidation deodorizing catalyst, 12. : Exhaust duct (exhaust path), 14: Food to be cooked.

Claims (1)

[Claims] A heater that heats the food to be cooked in the cooking chamber is installed, an oxidation deodorization catalyst having a three-dimensional porous material as a support is installed in the exhaust path that exhausts the air in the cooking chamber, and a A heating cooking device characterized by being equipped with a barrier body that blocks air flow.