JPH0961042A - Deodorizing heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectually adsorb, decompose, and deodrize all odor components by covering a heat production part of a glass pipe or a metal pipe heater with a catalyst layer having a specific composition. SOLUTION: This deodorizing heater 33 having a catalyst covering layer 37 on an effective heat production part surface of a glass pipe heater 36 is disposed below a condenser of a refrigerator. The catalyst covering layer 37 is constructed by forming a metal oxide or copper oxide such as manganese dioxide, a perovskite type metal oxide, hexaaluminate, a catalyst material such as alumina carrying platinum metal, and an adsorbent such as zeolite using a coupler such as aluminum hydroxide, alumina zol, and silica gel. In a cooling operation, air containing odor components passing through the inside of a condenser chamber touches the deodrizing heater 33 to permit the odor components to be adsorbed into the catalyst covering layer 37 and be removed. The construction is simple, an instlalation space is reduced, and all odor components including neutral odor components such as acetaldehyde are effectually adsorbed, decomposed, and deodrized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing heater, and more particularly to a deodorizing heater having a function of removing malodorous components.

[0002]

2. Description of the Related Art In the case of refrigerators, for example, various foods such as vegetables, meat, fish, etc. generate odors in the refrigerator, and the odors are circulated in a closed system in the refrigerator, so that the odor is muffled. This smell was attached to the food, thus deteriorating the quality of the food.

In order to solve these problems, for example, there is a deodorizing heater for a refrigerator as described in Japanese Patent Laid-Open No. 2-194816.

Hereinafter, a conventional heater for deodorizing a refrigerator will be described. 9 is a vertical cross-sectional view of the upper part of the refrigerator showing a state in which a conventional deodorizing heater is arranged in the refrigerator, FIG. 10 is an enlarged vertical cross-sectional view of a main part, and FIG. 11 is an enlarged cut-away front view.

First, in FIG. 9, 1 is a refrigerator main body, 2 and 3 are freezer compartments and refrigerating compartments formed therein, and 4 and 5 are doors, respectively. Reference numeral 6 denotes a cooler provided in a cooler room 7 at the back of the freezing room 2, and reference numeral 8 denotes a fan provided above the cooler 6.

When the fan is driven, a part of the air cooled by the cooler 6 is supplied into the freezer compartment 2 from the supply port 9, and the air in the freezer compartment 2 is cooled by the return duct 10. The freezing chamber 2 is cooled by being circulated so as to be returned to the inside of the chamber 7.

A part of the air cooled by the cooler 6 is supplied into the refrigerating compartment 3 via the supply duct 11, and the air in the refrigerating compartment 3 is supplied into the cooler compartment 7 via the return duct 12. It is circulated so that it is returned to the refrigerator room 3
The inside is cooled. In this case, the cooler chamber 7, the freezing chamber 2 and the return duct 10 form a circulation path through which the air in the freezing chamber 2 circulates.

[0008] The cooler room 7, the supply duct 11, the refrigerating room 3, and the return duct 12 constitute a circulation path through which the air in the refrigerating room 3 circulates.

Reference numeral 13 denotes a cooler 6 at the lower part of the cooler room 7.
The defrost heater disposed below the
A glass tube heater having a heater wire 13b provided in a glass tube 13a as shown in FIG. 7 is energized only when the cooler 6 is defrosted, and the rest is cut off. .

Reference numeral 14 denotes a water drop prevention member provided on the defrosting heater 13 so as to cover the defrosting heater 13 from above, which is made of a metal plate such as aluminum having heat resistance and water resistance, as shown in FIG. It is formed in the shape of a shallow container with an open lower side, and prevents defrost water from splashing on the defrost heater 13 during defrosting of the cooler 6.

Reference numeral 15 is a deodorant, which is an adsorbent layer 15 made of an adsorbent such as activated carbon or silica (silicon dioxide).
and a catalyst layer 15b made of platinum or nickel provided on the surface of the adsorbent layer 15a has a two-layer structure.

Here, the deodorant body 15 forms a plate-shaped adsorbent layer 15a by sintering an adsorbent, and after the adsorbent layer 15a is immersed in a catalyst solution to adhere the catalyst to the surface. The catalyst layer 15b is formed on the surface of the adsorbent layer 15a by heat treatment.

The adsorbent layer 15a and the catalyst layer 15b are each porous so that air can flow inside. The deodorizing body 15 is supported and fixed to the inner surface of the water drop prevention member 14 by a supporting member 17 via a heat insulating material 16 made of glass fiber or the like, and is provided near the defrosting heater 13.

Reference numeral 18 denotes a cover member, for example, a wire mesh, which is formed of a material having a high thermal conductivity and has a large number of through holes.
It is provided so as to cover the surface of the deodorant body 15.

The operation of the deodorizing heater of the refrigerator constructed as described above will be described below.

In the above-mentioned structure, during the cooling operation, the air in the refrigerator is blown by the air blowing action of the fan 8 to cool the cooler chamber 7 and the freezer chamber 2.
And is circulated through the cooler room 7, the supply duct 11, the refrigeration room 3 and the return duct 12. At this time, the air passing through the cooler chamber 7 comes into contact with the deodorant body 15 through the through holes of the wire net 18, and the odorous component contained in the air is adsorbent layer 15 of the deodorant body 15.
Adsorbed by a and removed.

On the other hand, when the defrosting operation is started, the cooler 6
And the operation of the fan 8 is stopped, while the defrost heater 13
Is energized and generates heat. Due to the heat generated by the defrosting heater 13, the cooler 6 is heated to perform defrosting, and the deodorant body 15 is also heated. At this time, since the surface of the deodorizer 15 is covered with the wire net 18, the heat transfer of the wire net 18 allows the deodorizer 15 to be heated as uniformly as possible. In the heated deodorizer 15, the odor component adsorbed by the adsorbent of the adsorbent layer 15a is desorbed, and at the same time, the odor component is oxidatively decomposed and removed in the catalyst layer 15b.

Then, the deodorizing body 15 is heated in this way, so that the adsorption function, that is, the deodorizing function is reproduced. At this time, the water drop prevention member 14 plays a role of efficiently confining the heat from the defrosting heater 13 to heat the deodorizing body 15 efficiently, and at the same time, deodorizing body 15 and the defrosting heater 1
It is prevented that the defrosting water from the cooler 6 is applied to the water cooler 3.

The heat insulating material 16 suppresses the heat of the deodorizing body 15 from being radiated from the water drop prevention member 14, and deodorization is caused by defrosting water falling on the water drop prevention member 14 and the water drop prevention member 14 being rapidly cooled. The heat shock of the body 15 is prevented.

Further, the wire netting 18 prevents the deodorizing body 15 from dropping and scattering if the deodorizing body 15 is damaged.

When the defrosting operation is finished and the cooling operation is restarted, and the temperature of the deodorizing body 15 is lowered, the odorous components contained in the air in the refrigerator are adsorbed and removed by the deodorizing body 15 as described above. Will be done.

[0022]

However, in the above-mentioned constitution, it is possible to absorb and decompose acidic odors and basic odors such as trimethylamine generated from meat and fish, and methyl mercaptan generated from vegetables, from grains. It is impossible to adsorb and decompose a neutral odor component such as acetaldehyde that is generated, and as an intervening substance other than the water drop prevention member 14 between the defrost heater 13 and the cooler 6, the deodorizing body 15, the heat insulating material 16, The support 17 and the wire mesh 18 are present, which makes the structure complicated.

Further, as a result, it is necessary to increase the plate thickness of the water drop prevention member 14 in order to hold the deodorant body 15, and to increase the temperature of the deodorant body 15, the defrost heater 13 and the water drop prevention member. It is necessary to make the distances 14 closer to each other.
It will be in the state of entering the shallow bottom part of. For these reasons, there is a drawback in that the rise of convective heat to the cooler 6 of the defrost heater 13 is hindered, the defrost time becomes longer, and the defrost performance of the refrigerator deteriorates.

In order to prevent the defrosting performance of the refrigerator from deteriorating, if the temperature of the defrosting heater 13 is raised to shorten the defrosting time, the temperature of the deodorizing body 15 becomes excessive, so that the deodorizing effect of the deodorizing body 15 is improved. It has the drawback of becoming low.

Further, since one surface of the deodorizing body 15 is in contact with the heat insulating material 16, the surface of the deodorizing body 15 is covered with the metal net 18, and the water drop prevention member 14 needs to be large, However, it has a drawback that the air circulated in the storage is bad and the deodorizing effect is low.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a deodorizing heater which efficiently adsorbs all odorous components and decomposes and deodorizes them.

[0027]

To achieve this object, the deodorizing heater of the present invention comprises a catalyst coating layer containing at least an oxide of a transition metal element, zeolite, activated alumina and a platinum group metal, and an electric resistor. The entire or a part of the effective heat generating portion on the surface of the glass tube heater or the metal tube heater containing the is covered.

Further, a glassy film is formed on the surface of the metal tube heater or a fin provided on the outer periphery of the metal tube heater and made of a material having a relatively high thermal conductivity, and the catalyst coating layer is formed on the glassy film. .

[0029]

According to this structure, since there are no components other than the water drop prevention member and the deodorizing heater, and the structure is simple because the deodorizing body is the catalyst coating layer, the circulating air in the chamber containing the odorous component is The water drop prevention member and the catalyst coating layer of the deodorizing heater are well exposed to the wind, and the odor is efficiently adsorbed.

Further, the catalyst coating layer on the surface of the deodorizing heater is capable of deodorizing by adsorbing and decomposing a neutral odor component such as acetaldehyde which could not be adsorbed by the conventional method. Covered so as to cover, the heat of the electric resistance wire is transmitted to all the catalyst coating layers to decompose and deodorize the adsorbed odorous components.

Since the water drop prevention member and its catalyst coating layer have no inclusions between the deodorizing heater and the heat of the metal tube heater, they reach the catalytic activation temperature in a short time and decompose the adsorbed odorous components. Deodorize.

As a result, the size of the water drop prevention member can be made small and the distance between the deodorization heater and the water drop prevention member can be increased, and the inhibition of the rise of convective heat to the cooler of the deodorization heater is reduced and the defrosting performance is improved. There is no drop.

Further, even if the temperature of the deodorizing heater is raised to further improve the defrosting performance, the deodorizing performance is not deteriorated.

Further, the size of the water drop prevention member can be reduced and the distance between the deodorization heater and the water drop prevention member can be increased, so that the air circulation of the circulating air in the refrigerator to the deodorization heater is improved and the deodorization effect is enhanced.

[0035]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of the upper part of the refrigerator showing a state in which the deodorizing heater according to the first embodiment of the present invention is installed in a refrigerator, FIG. 2 is an enlarged vertical cross-sectional view of a main portion, and FIG. It is a front view.

In FIG. 1, 21 is a refrigerator body,
Reference numerals 22 and 23 denote freezer compartments and refrigerating compartments formed therein, and 24 and 25 doors, respectively. Reference numeral 26 is a cooler installed in the cooler room 27 at the back of the freezing room 22, and 28 is a fan installed above the cooler 26. When the fan 28 is driven, a part of the air cooled by the cooler 26 is supplied from the supply port 29 into the freezing room 22, and the air in the freezing room 22 is returned to the cooler room 27 via the return duct 30. The freezing compartment 22 is cooled by the circulation.

Part of the air cooled by the cooler 26 is supplied to the refrigerating compartment 23 via the supply duct 31, and the air in the refrigerating compartment 23 is returned to the cooler compartment 27 via the return duct 32. The inside of the refrigerator compartment 23 is cooled by the circulation. In this case, the cooler room 27, the freezing room 22, and the return duct 30 constitute a circulation path through which air in the freezing room 22 circulates, and the cooler room 27, the supply duct 31,
The refrigerating room 23 and the return duct 32 constitute a circulation path through which the air in the refrigerating room 23 circulates.

Reference numeral 33 is a deodorizing heater disposed below the cooler 26. This is a glass tube heater 36 in which an electric resistance wire 35 is provided in a glass tube 34 as shown in FIGS.
The catalyst coating layer 37 is provided on the surface of the effective heat generating portion. The catalyst coating layer 37 adsorbs a catalyst substance such as manganese dioxide, a perovskite type metal oxide, a metal oxide such as hexaaluminate or copper oxide (an oxide of a transition metal element), an alumina-supported platinum metal, and zeolite. The agent is formed using a suitable binder such as alumina hydroxide, alumina sol, silica gel and the like.

The glass tube heater 36 also serves as a defrosting heater for the refrigerator, and is energized only when the cooler 26 is defrosted, and the rest is cut off. Reference numeral 38 is a water drop prevention member provided so as to cover the deodorization heater 33 from above in order to prevent defrost water from splashing on the deodorization heater 33, and is made of, for example, aluminum or stainless steel having heat resistance and water resistance. Made of metal.

The operation of the deodorizing heater of the refrigerator configured as described above will be described below.

During the cooling operation, the air in the refrigerator is circulated through the cooler chamber 27, the freezing chamber 22 and the return duct 30 by the blowing action of the fan 28, and the cooler chamber 27, the supply duct 31, the refrigerating chamber 23 and the return are performed. It is circulated through the duct 32. At this time, the air containing the odorous component passing through the inside of the cooler chamber 27 comes into contact with the deodorizing heater 33, and the odorous component is adsorbed by the catalyst coating layer 37 and removed.

Next, when the defrosting operation is started, the cooler 2
While the operation of the fan 6 and the fan 28 is stopped, the deodorizing heater 33 is energized to generate heat. Since the catalyst coating layer 37 of the deodorizing heater 33 is installed so as to cover the outer periphery of the glass tube 34, the heater is heated in the entire circumferential direction from the electric resistance wire 35, and the deodorizing heater 33 is heated to the activation temperature in a short time. Can be

At this time, the catalyst coating layer 37 of the deodorizing heater 33
The odorous components adsorbed on the catalyst are released when the catalyst coating layer 37 is heated to the activation temperature, and at the same time, they are oxidatively decomposed by the chemical action of the catalyst substance to become odorless. Then, the adsorption ability of the catalyst coating layer 37 is regenerated.

On the other hand, the water drop prevention member 38 and the deodorizing heater 33
Since there is no inclusion between them and the water drop prevention member 38 does not need to hold the inclusion, the size can be reduced. Further, since there is no inclusion between the deodorizing heater 33 and the water drop prevention member 38, the catalyst coating layer 37 of the circulating air in the chamber containing the odorous component is present.
The odor component is efficiently adsorbed because the wind contact with the air is improved.

In addition, the catalyst coating layer 37 is a thin porous coating layer applied by, for example, a spray method, and can be easily raised to the activation temperature.

Next, a second embodiment of the present invention will be described with reference to the drawings. 4 and 5 show a second embodiment of the present invention.
FIG. 3 is an explanatory diagram of a deodorizing heater in the example of FIG. Since the operation when installed in the refrigerator is similar to that of the first embodiment,
1 and 3 are assigned the same reference numerals and detailed description thereof is omitted.

Reference numeral 43 denotes a deodorizing heater fitted in the horizontal type cooler 26, and transmits the temperature rise of the defrost heater due to heat generation during the defrosting operation to the cooler 26 by heat conduction. This deodorizing heater 43 has a catalyst coating layer 37 on the surface of the effective heat generating portion of a metal tube heater 46 having an electric resistor provided in the metal tube.

Regarding the operation of the deodorizing heater 43 configured as described above, the differences from the first embodiment will be mainly described, and other details will be omitted because they are the same.

During the cooling operation, the air in the refrigerator is circulated by the blowing action of the fan 28, and the air containing the odorous component contacts the deodorizing heater 43, and the odorous component is adsorbed on the catalyst coating layer 37 and removed.

Next, when the defrosting operation is started, the cooler 2
6 and the fan 28 are stopped, the deodorizing heater 43 is energized to generate heat. At this time, the odorous components adsorbed on the catalyst coating layer 37 of the deodorizing heater 43 are released by heating the catalyst coating layer 37 to the activation temperature, and at the same time, they are oxidatively decomposed by the chemical action of the catalyst substance and become odorless. Turn into. Then, the adsorption ability of the catalyst coating layer 37 is regenerated.

Since the metal tube heater 46 defrosts by heat conduction as described above, it can be applied to a cooler having a large area, and a large surface area can be taken, so that the deodorizing ability can be improved. Further, since it is the metal tube heater 46, it is strong against shock and vibration, excellent in safety, and expanded in usage.

FIG. 6 is a perspective view of a deodorizing heater according to the third embodiment, and FIG. 7 is a cross-sectional view of the main part thereof.

Since the state of being installed in the refrigerator is the same as that of the second embodiment, the drawing is omitted. 53 is a deodorizing heater in which a metal tube 54 with fins is fitted on the surface of a metal tube heater 46 in which an electric resistor 45 is provided in the metal tube 44. The metal tube 54 is formed by coating a glassy film 57 on the surface of a base material 55 made of a material having a relatively high thermal conductivity such as aluminum by, for example, enamel processing, and further coating the surface by a dip coating method or the like. It has a catalyst coating layer 37.

With respect to the operation of the deodorizing heater configured as described above, the difference from the first embodiment will be mainly described, and the other details will be omitted because they are the same.

During the cooling operation, the air in the refrigerator is circulated by the blowing action of the fan 28, and the air containing the odorous component comes into contact with the deodorizing heater 53, and the odorous component is adsorbed on the catalyst coating layer 37 and removed.

Next, when the defrosting operation is started, the cooler 26
While the operation of the fan 28 is stopped, the metal tube heater 46 is energized to generate heat and the temperature of the metal tube 54 rises. As a result, the odorous components adsorbed on the catalyst coating layer 37 of the metal tube 54 are released by heating the catalyst coating layer 37 to the activation temperature and, at the same time, are oxidized and decomposed by the chemical action of the catalyst substance and are odorless. Turn into. Then, the adsorption capacity of the catalyst coating layer 37 is regenerated.

At this time, since the metal tube 54 is in contact with the metal tube heater 46, heat transfer from the metal tube heater 46 can be performed by convection as well as conduction, so that the catalyst coating layer 37 is heated very much. Can be effective. As a result, the volume of the catalyst coating layer 37 can be increased, and the deodorizing effect can be further enhanced.

Further, since the surface of the metal tube 54 is coated with the vitreous coating 57 by the enamel process or the like, the surface of the metal tube is completely covered with the moisture of the air, so that the corrosion due to the potential difference with the catalyst material is caused. Can be prevented. Further, since a uniform film having a good affinity with the liquid containing the catalyst at the time of coating can be formed, a catalyst layer of stable quality can be obtained.

FIG. 8 is a sectional view of the essential parts of a deodorizing heater according to the fourth embodiment. Example 2 when installed in a refrigerator
Since it is similar to the above, the drawing is omitted.

Reference numeral 63 is a deodorizing heater, and a glass coating 57 is applied to the surface of the metal tube heater 46 having the electric resistor 45 in the metal tube 44 by, for example, enamel treatment, and the surface is further dip coated. It has a catalyst coating layer 37 coated by a method or the like.

With respect to the operation of the deodorizing heater configured as described above, the difference from the first embodiment will be mainly described, and the other details will be omitted because they are the same.

During the cooling operation, the air in the refrigerator is circulated by the blowing action of the fan 28, the air containing the odorous component comes into contact with the deodorizing heater 63, and the odorous component is adsorbed on the catalyst coating layer 37 and removed.

Next, when the defrosting operation is started, the cooler 2
6 and the fan 28 are stopped, the deodorizing heater 63 is energized to generate heat. At this time, the deodorizing heater 63
The odorous components adsorbed on the catalyst coating layer 37 are released by heating the catalyst coating layer 37 to the activation temperature, and at the same time, they are oxidatively decomposed and deodorized by the chemical action of the catalyst substance. Then, the adsorption ability of the catalyst coating layer 37 is regenerated.

Since the metal tube heater 46 defrosts by heat conduction as described above, it can be applied to a cooler having a large area, and a large surface area can be taken, so that the deodorizing ability can be improved. Further, since it is the metal tube heater 46, it is resistant to shock and vibration, has excellent safety, and its usage is expanded.

Further, since the vitreous coating 57 is applied to the surface of the metal tube heater 46 by the enamel treatment or the like, the surface of the metal tube heater 46 is completely covered with the moisture of the air, and therefore, the catalyst material is used. Corrosion can be prevented by the potential difference. Further, since the affinity for the liquid containing the catalyst at the time of coating is good and a uniform film can be formed, a catalyst layer of stable quality can be obtained.

Further, the catalyst coating layer 37 of the present invention is made of manganese dioxide, perovskite type metal oxide, metal oxide such as hexaaluminate or copper oxide (oxide of transition metal element), alumina-supported platinum group metal and the like. A suitable binder such as a catalytic material and an adsorbent such as zeolite, for example, alumina hydroxide,
It is formed by using together with alumina sol, silica gel and the like. Of these, copper oxide and alumina platinum group metals are most preferably used as the catalyst coating material from the viewpoint of heat resistance and poisoning resistance. Furthermore, the catalyst coating layer 37 of the present invention
It is desirable to include silica in. By containing silica, the adhesion of the catalyst coating layer 37 to the exterior of the heating element such as a glass tube can be strengthened.

[0068]

As described above, according to the present invention, at least the oxide of the transition metal element, the zeolite, and the activated alumina are provided in the whole or a part of the effective heating portion on the surface of the glass tube or metal tube heater containing the electric resistor. By covering with a catalyst coating layer containing silica and platinum group metal, the structure is simple, the space required for installation is small, and all odors including neutral odor components such as acetaldehyde that could not be adsorbed in the past can be absorbed. It is possible to provide a heat-resistant deodorizing heater that efficiently adsorbs components to decompose and deodorize them, and that does not deteriorate the deodorizing performance even when the temperature of the heat generating part is raised.

Since the metal tube heater can be used for defrosting by heat conduction, it can be applied to a cooler having a large area. In addition, the metal tube heater has a relatively high thermal conductivity on the outer circumference. By providing the fins made of a material, the surface area can be further increased, so that the deodorizing ability can be further improved. Moreover, it is possible to provide a deodorizing heater that is resistant to shock and vibration and is excellent in safety.

Furthermore, the surface of the metal tube or fins is protected by forming a glassy film on the surface of the metal tube or the fins provided on the outer periphery of the metal tube, so that the surface of the metal tube or fins is not easily affected by moisture in the air and the catalyst is Corrosion due to the potential difference with the material can be prevented. In addition, since it has a good affinity with the liquid containing the catalyst at the time of coating and can form a uniform film, a catalyst layer of stable quality can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an upper portion of a refrigerator showing a state in which a deodorizing heater according to a first embodiment of the present invention is installed in a refrigerator.

FIG. 2 is an enlarged vertical cross-sectional view of a main part of the deodorizing heater shown in FIG.

FIG. 3 is an enlarged cutaway front view of a main part of the deodorizing heater shown in FIG.

FIG. 4 is a vertical cross-sectional view of the upper part of the refrigerator showing a state where the deodorizing heater according to the second embodiment of the present invention is installed in the refrigerator.

FIG. 5 is a perspective view of a deodorizing heater according to second and fourth embodiments.

FIG. 6 is a perspective view of a deodorizing heater according to a third embodiment.

7 is a cross-sectional view of a main part of the deodorizing heater shown in FIG.

FIG. 8 is a sectional view of a main part of a deodorizing heater according to a fourth embodiment.

FIG. 9 is a vertical cross-sectional view of the upper part of the refrigerator showing a state in which a conventional deodorizing heater is installed in the refrigerator.

FIG. 10 is an enlarged vertical cross-sectional view of a main part of the deodorizing heater shown in FIG.

FIG. 11 is an enlarged cutaway front view of a main part of the deodorizing heater shown in FIG.

[Explanation of symbols]

 33, 43, 53, 63 Deodorizing heater 36 Glass tube heater 37 Catalyst coating layer 46 Metal tube heater 57 Glass film

Claims (4)

[Claims] 1. A catalyst coating having at least an oxide of a transition metal element, zeolite, activated alumina, silica, and a platinum group metal on the whole or a part of the surface of an effective heat generating portion of a glass tube heater containing an electric resistor. Deodorizing heater coated with layers. 2. An oxide of a transition metal element, zeolite, activated alumina, silica, and a platinum group metal are formed on all or part of the surface of an effective heat generating portion of a metal tube heater such as a sheathed heater having an electric resistor built therein. A deodorizing heater coated with a catalyst coating layer having. 3. The metal tube heater has fins made of a material having a relatively high thermal conductivity, such as aluminum, on the outer periphery thereof, and the surface of the fins is coated with a glassy film. Deodorizing heater. 4. The deodorizing heater according to claim 2, wherein the metal tube heater has a vitreous coating on the outer periphery thereof.