JP2864786B2 - Hot air heater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot air heater such as an oil fan heater.

[0002]

2. Description of the Related Art First, a description will be given of a hot air passage forming member (hereinafter referred to as a duct) of a conventional oil fan heater with reference to FIG.

[0003] As shown in FIG. 3 , the combustion gas burned in the burner section 5 passes through a combustion tube 9, passes through a catalyst 6, and is guided to a lower duct 7. On the other hand, the indoor air taken in by the rotation of the blower fan 8 exchanges heat with the combustion tube 9 to become hot air,
The gas passes between the upper duct 10 and the lower duct 7 and is discharged from the outlet 11 together with the combustion gas. Since the high-temperature combustion gas passes through the lower duct 7, the lower duct 7 is generally made of a hot-dip aluminum-plated steel plate or a stainless steel plate. On the other hand, since the upper duct 10 does not exceed 100 ° C. at the highest, it is coated with a metal oxide or the like on a galvanized steel sheet or a galvanized steel sheet or a zinc-iron alloy plated steel sheet alloyed by heat treatment after galvanizing. Steel plates and the like are used. A temperature detecting element 12 for preventing abnormal heating of the hot air heater main body (hereinafter referred to as main body) is mounted on one of the upper surface, the front surface, and the side surface of the upper duct 10.

[0004]

However, in the above configuration of the conventional oil fan heater, since the upper duct 10 on which the temperature detecting element 12 is mounted uses a galvanized steel plate or the like, the upper duct 10 is heated by hot air. The surface may have turned gray-black over time. In addition, indoors with warm air fan 8
When the small dust and the like taken in when the air is taken in adhere, they may be burned and further promote discoloration of the surface. In the duct 10 top portion for mounting the temperature sensing element 12 on the duct 10 when the color change as described above progresses
The emissivity of the constituent materials increases. That is, upper duct 1
0 itself will increase in temperature. Abnormal pressure in order that
The temperature of the mounting surface of the temperature detecting element 12 for detecting heat
Therefore, there is a problem that the heating prevention device operates and stops the operation despite the normal combustion state. Further, there has been a problem that the temperature change of the upper duct 10 also causes a temperature change of peripheral parts, which adversely affects the durability and reliability of the parts.

[0005] Discoloration is a phenomenon that occurs because the galvanized layer of a galvanized steel sheet inter-diffuses with the iron component in the steel sheet, which is a material, and alloys with the passage of time at a hot air temperature. As the alloying proceeds, the amount of discoloration increases, and the emissivity also increases. On the other hand, the zinc-iron alloyed plated steel sheet which has been alloyed in advance to suppress the secular discoloration, the discoloration degree does not change, but the emissivity is high, so the temperature of the upper duct 10 itself is high, and the peripheral parts in the main body are In an atmosphere containing a large amount of moisture such as combustion exhaust gas due to problems such as a rise in temperature or the diffusion of iron atoms to the surface
There is a problem that red rust is formed in an atmosphere containing corrosive gas in combustion exhaust gas and the corrosion resistance is poor.

The present invention has the order to solve the above problems, prevents the occurrence of discoloration and rust due to the temperature rise of the upper duct 10 surface, malfunction or of the temperature detecting element 12 provided in the upper duct 10, the peripheral parts It is an object of the present invention to provide a hot air heater that does not cause abnormal temperature.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, a hot air heater according to the present invention vaporizes kerosene and mixes it with combustion air.
Burner that burns together and is generated at this burner
A combustion tube for exchanging heat of the combustion gas, and an outlet for the combustion gas
Upper duct and lower duct that constitute a hot air passage for guiding
And the temperature at which the heater is placed
The hot-air passage forming member comprises a steel plate electroplated with a zinc-nickel alloy containing at least 10% or more and at most 15% nickel as a main component.

According to the present invention, the zinc-nickel plating layer having a high melting point reduces discoloration on the surface of the steel sheet,
In addition, the emissivity is reduced, and the change over time is suppressed.
For this reason , the upper duct which is a component of the hot air passage of the hot air heater
Even when used for emissivity, changes in emissivity over time due to discoloration, etc.
Very rarely installed on the upper duct surface to detect abnormal heating
Temperature fluctuations and temperature rise of the malfunction or surrounding components of the heating prevention by temperature rise of the temperature detecting element portion for output can be eliminated. Further, since it is hardly affected by the combustion gas component, the problem of promoting discoloration and a decrease in emissivity due to the combustion gas can be solved.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. Note the same thing only the upper duct Unlike other from the conventional example, the description thereof is omitted by assigning the same numbers.

First, nickel 11% -zinc.
The remaining alloy is electroplated and chemically treated (chromate treatment)
A hot air heater incorporating the upper duct 10a shown in FIG. Table 1 shows the emissivity of the upper duct 10a after the hot-air heater shown in FIG. 2 was subjected to a strong combustion operation for a maximum of 5000 hours, and the emissivity was a value measured at 85 ° C. It is.

[0011]

[Table 1]

The above table also shows the results of the emissivity of the upper duct 10 similarly prepared for conventionally used galvanized steel sheets, zinc-iron alloyed coated steel sheets, and metal oxide-coated steel sheets.

As can be seen from Table 1, the emissivity of the upper duct 10a of the present invention has a low absolute value and 5000
It was low and stable after burning for hours. On the other hand, the conventional emissivity of the upper duct 10 made of galvanized steel sheet is lower than that of the upper duct 10a of the present invention, but gradually increases to 5000.
After the time combustion, it fluctuated greatly. When the emissivity increases, the temperature inside the main body outside the upper ducts 10 and 10a increases. In the conventional upper duct 10 made of galvanized steel sheet, the temperature inside the main body outside the upper duct 10 increased after burning for 5000 hours, but in the upper tart 10a of the present invention, the temperature inside the main body outside the upper duct 10a almost changed. Did not. On the other hand, the emissivity of the upper duct 10 made of a zinc-iron alloyed plated steel sheet or the upper duct 10 made of a metal oxide-coated steel sheet did not change so much before and after combustion, but the emissivity was high due to the high emissivity. The temperature inside the body was high. Also shows a comparison of the red rust occurrence on the duct 10,10a after each operation time below (Table 2).

[0014]

[Table 2]

As is clear from Table 2, the conventional upper duct 10 made of a hot-dip galvanized steel sheet was good, but other electro-galvanized steel sheets and zinc-iron alloyed coated steel sheets had corrosion resistance. Was inferior. On the other hand, the upper duct 10a adopting the present invention exhibited the same or higher corrosion resistance as the hot-dip plating having a large basis weight while being an electroplating with a small basis weight.

FIG. 1A is a schematic diagram of an initial section of a zinc-nickel alloy-plated steel sheet used in the hot air heater of the present invention, and FIG. 1B is an enlarged cross-sectional view after 5000 hours of burning. Figure 1
As shown in (a) , a zinc-nickel alloy plating layer 2 is formed on a cold rolled steel sheet 1 and a chemical conversion (chromate) layer 3 is formed on the surface. After burning for 5000 hours,
As shown in FIG. 1B, the zinc-nickel alloy plating layer 2
A slightly zinc-nickel alloy plating layer 2 and a layer 4 in which iron in the cold-rolled steel sheet 1 was alloyed were observed between the steel sheet 1 and the cold-rolled steel sheet 1. However, this was a very thin layer. This shows that the alloy plating layer 2 and the cold-rolled steel sheet 1 are hardly alloyed. The temperature of the upper duct 10a is sufficiently low for the progress of alloying. This is because the addition of nickel to zinc increases the melting point of plating.

The alloying of zinc in the zinc-nickel alloy plating layer 2 with iron in the cold-rolled steel sheet 1 is suppressed by the addition of nickel, but the effect of suppressing nickel at a high temperature (for example, 300 ° C.) is as follows. It becomes remarkable over almost 10%. That is, if it is 10% or less, the effect on heat resistance is small. However, nickel is expensive and the production of plated steel sheet becomes difficult when the addition amount is increased, and the nickel component amount is 10 to 15% from the viewpoint of increasing the production cost.
The degree is considered to be the best.

Although not shown in the embodiment of the present invention, if the properties of the zinc-nickel alloy-plated steel sheet of the upper duct 10a used in the hot air heater of the present invention are maintained, the plated steel sheet may be used. In order to improve the performance, a minute amount of a component element such as cobalt or titanium may be added to the zinc-nickel alloy.

As is apparent from the above description, the hot air heater of the present invention has an increased heat resistance and a low initial emissivity because the upper duct is made of a zinc-nickel alloy electroplated steel sheet. The surface discoloration over a long period of time
Variation of emissivity is reduced, aging of the temperature detecting element mounting surface
This has the effect of preventing a malfunction during normal combustion due to an excessive temperature rise. In addition, since the temperature fluctuation and rise of the parts around the upper duct in the hot air heater main body are reduced, the reliability of those parts is increased and a safe product can be provided. Furthermore, the upper duct
Because of its excellent corrosion resistance against combustion gases and the like, the product life is prolonged. Since the zinc-nickel alloy electroplated steel sheet is used, the dimensional stability of the thickness of the upper duct is excellent, and the effect on production is great.

[Brief description of the drawings]

FIG. 1A is an enlarged schematic cross-sectional view of a zinc-nickel alloy-plated steel sheet constituting an upper duct of a hot air heater according to one embodiment of the present invention. FIG. Schematic enlarged cross-sectional view after 5000 hours of combustion

FIG. 2 is a cross-sectional view of the hot air heater.

FIG. 3 is a cross-sectional view of a conventional hot air heater.

[Description of Signs] 1 Steel plate 2 Zinc-nickel alloy plating layer 10a Upper duct (hot air passage constituent member) 12 Temperature detection element

Continuation of front page (72) Inventor Kunio Kanda 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-2-43040 (JP, A) (58) Fields investigated (Int .Cl. ⁶ , DB name) F24H 9/02 302 F24H 3/04 301

Claims (1)

(57) [Claims] (1) kerosene is vaporized and mixed with combustion air to be burned.
And the combustion gas generated in the burner
A combustion cylinder to be exchanged and a pipe for guiding the combustion gas to an air outlet.
The upper and lower ducts that make up the hot air passage
A temperature detecting element disposed at an appropriate position in the air passage to detect abnormal heating , wherein the hot air passage constituting member is zinc-nickel containing at least 10% or more and at most 15% nickel as a main component. Hot air heater made of steel plate electroplated with alloy.