JPH07320850A - Ptc pipe heater - Google Patents

Abstract

PURPOSE:To easily exchange materials to be heated in PTC pipe heater. CONSTITUTION:PTC elements 2 are thermally joined to more than n/2 outer faces of an n-sided polygonal metal (stainless steel, etc.) or ceramic (main components are alumina, etc.) pipe 3. The PTC elements 2 and the metal pipe 3 are electrically insulated at least one face of the PTC elements 2. The PTC elements 2 or electrode layers of the PTC elements and junction parts of electrode plates 1 are joined by conductive adhesive and their circumference can be fixed by heat-resisting resin 4. An elastic body can be intervened between an in-pipe insertion material and the pipe. Respective PTC elements can be thermally joined on opposed two faces of a U-shaped sectional metal base body whose one face is cut out among polygonal pipes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a positive temperature coefficient thermistor (P
The present invention relates to a device for heating a gas, a fluid, and particularly a solid body by using a TC element).

[0002]

2. Description of the Related Art Conventionally, since a PTC heater has a self-temperature control function, it has been used for various purposes as a safe heating source. Also, as the applications have expanded, various shaped units have been developed. Among these,
As a simplification, as disclosed in Japanese Patent Laid-Open No. 54-115446, the PTC element 2 is provided in the porcelain case 7.
Is incorporated (see FIG. 18).

On the other hand, in order to apply the above-mentioned PTC heater unit to a solid material in the form of a prism, which is an object to be heated, such as a honeycomb catalyst, a sensor element, and heating, as shown in FIG. In addition, the PTC heater unit 9 is directly fixed to the object to be heated 8 by using the heat resistant adhesive 10 and used.

[0004]

In this case, since the objects to be heated are easily damaged by ceramics, it is difficult to fix them mechanically, and it is necessary to firmly bond them by using a heat resistant adhesive. In the case of a honeycomb structure, it was technically difficult. In addition, if the honeycomb catalyst is clogged or mechanically damaged, the heater section must be replaced, which causes a problem of high operating cost.

The problem to be solved by the present invention is to provide a pipe-shaped heater in which an object to be heated can be easily replaced.

[0006]

In order to solve the above problems, in the PTC pipe heater of the present invention, PTC elements are thermally joined to the outer surface of n / 2 or more of an n-gonal metal or ceramic pipe. It is characterized by being

The embodiment of this PTC pipe heater is as follows. The material of the metal pipe is stainless steel, and the material of the ceramic pipe is mainly alumina. At least one surface of the PTC element is electrically insulated from the PTC element and the metal pipe. The PTC element or the electrode layer of the PTC element and the joint portion of the electrode plate are joined by a conductive adhesive, and the periphery thereof is fixed by a heat resistant resin. An elastic body is interposed between the pipe insert and the pipe. The end portion of the electrode plate for applying a voltage formed on the PTC element has a tab structure. A hole is formed in the terminal lead-out portion of the electrode plate, and a heat resistant resin is poured into the hole to fix the electrode plate and the PTC element.

In the polygonal pipe, P is provided on each of two opposing surfaces of a metal base having a U-shaped cross section, one surface of which is cut off.
The TC element may be thermally bonded.

[0009]

In the present invention, PT is formed on the outer surface of the square metal pipe.
The C element is joined, and the object inside is indirectly heated from the metal pipe. PT on n / 2 or more of the n pipe surfaces
By joining the C elements and generating heat, the temperature unevenness of the heating object inside is reduced.

[0010]

EXAMPLES The present invention will be specifically described below based on examples.

Example 1 An electrode layer 6 was formed on the maximum surface at a Curie point of 100 ° C. and a room temperature resistance value of 70 to 80 Ω was 25 ×.
Install a 15 × 3 mm flat PTC element 2 (see Fig. 3)
I prepared one. Further, as shown in FIGS. 1, 2 and 4,
The pipe 3 made of metal (stainless steel) having a quadrangular cross section was bonded with the heat resistant resin 4 via the insulating plate 14. Further, the electrode layer 6 and the electrode plate 1 were bonded to each other using a conductive adhesive 5. After inserting the ceramic honeycomb article 8 to be heated into the pipe 3, as shown in FIG.
100V was electrically heated for 1 hour. After about 30 minutes, the temperature of the insert was measured and the core was heated to 100 ° C. The temperature distribution was 105 ° C. at maximum and 95 ° C. at minimum, which was within ± 5 ° C. which was the target.

Example 2 An electrode was formed on the maximum surface at a Curie point of 100 ° C. and a room temperature resistance value of 70 to 80 Ω was 25 × 15.
Six flat PTC elements 2 (see FIG. 3) having a size of 3 mm were prepared. Further, as shown in FIG. 6, these elements are fixed on both sides with electrode plates 1 by a conductive adhesive 5, and then heat-resistant resin 1 is applied to a metal pipe 3 having a hexagonal cross section through an insulating plate 14.
4 was used for adhesion. After inserting the ceramic object 8 to be heated in the pipe 3, the difference between the maximum temperature and the minimum temperature was measured by changing the number of energized elements using a switch 11 as shown in FIG. 6 at 100V. As a result, as shown in Table 1, the temperature unevenness did not occur with three or more and the temperature increased sufficiently, but the temperature did not rise with two and the temperature unevenness was large.
From the above, it became clear that it is necessary to have a configuration capable of raising the temperature of more than half of the number of heating surfaces.

[0013]

[Table 1]

Example 3 A pipe 3 having a quadrangular cross section and made of aluminum, brass or stainless steel was prepared, and a heater having the same structure as that of Example 1 was prepared. This pipe heater was placed at 40 ° C. and 90% R. It was left under the condition of H. 100
When the room temperature resistance value was measured after 0 hours, the aluminum and brass products showed an increase in resistance value of +100 to + 200%, but the stainless steel product showed about + 10%.

[Embodiment 4] When a heater having the same structure as that of Embodiment 1 is used and a ceramic object 8 to be heated is inserted into the pipe 3, as shown in FIG. 9, the silicone resin 4 is applied to the inner wall of the pipe. It was applied and heat-cured. As a result of further heating by applying 100 V, the temperature distribution of the object to be heated after about 30 minutes was 110 ° C. at the highest and 105 ° C. at the lowest, and both the temperature and the temperature distribution were improved.

[Embodiment 5] A heater having the same structure as that of Embodiment 1 and a heater in which the periphery of the element was surrounded by silicon resin were used and left at room temperature in an environment of O ₃ and 1000 ppm. As a result, after 100 hours, the one surrounded by the silicone resin had a room temperature resistance value of + 20%, but the one not surrounded by the resin showed an increase of + 300% in resistance value.

Example 6 The electrode layer 6 was formed on the maximum surface at a Curie point of 100 ° C. and a room temperature resistance value of 70 to 80 Ω was 25 ×.
Four 15 × 3 mm flat PTC elements 2 (see FIG. 3) were prepared. Further, as shown in FIGS. 7 and 8, the heat-resistant adhesive 10 was used to come into contact with the ceramic pipe 15 having a quadrangular cross section and a different alumina content, and then lowered. In addition, the electrode layer 6
The electrode plate 1 and the electrode plate 1 were bonded to each other using a conductive adhesive 5.
After inserting the ceramic article 8 to be heated having a honeycomb structure into the pipe 15, as shown in FIG.
The V was electrically heated. Regarding the temperature of the insert after about 30 minutes, as shown in Table 2, it was revealed that the temperature difference was remarkably reduced when a pipe having 50% by volume or more of alumina was used.

[0018]

[Table 2]

Similar results could be obtained by using an element having a shape as shown in FIGS. 10 and 11 and using it as shown in FIG.

As shown in FIG. 13, a PTC element may be thermally joined to two opposing surfaces of a metal base having a U-shaped cross section, one side of which is cut out of a polygonal pipe.

The end portion of the electrode plate 1 can be a tab terminal 12 as shown in FIG. Further, as shown in FIG. 15, a hole 13 is provided in the lead-out portion of the electrode terminal, a heat-resistant resin is poured in, and the periphery is fixed with a heat-resistant adhesive 10 as shown in FIGS. Even if a force is applied to the electrode plate 1, the electrode plate 1 is not easily peeled off and is stable.

[0022]

As described above, the present invention has the following effects.

Since the object to be heated is mounted inside the metal or ceramic pipe, even when the object to be heated is replaced due to clogging or the like, only the object to be heated inside is replaced. Is economical because it can be used as is.

By joining the element to the n / 2 surface or more of the n surfaces of the pipe surface to generate heat, it is possible to reduce the temperature unevenness of the heating object inside.

By electrically insulating the PTC element and the electrode plate with respect to the metal pipe, there is no fear of electric leakage and safety is improved.

By hardening the periphery of the conductive resin with a heat resistant resin, it is possible to protect an important conductive portion where an epoxy resin is frequently used.

By forming a hole in the lead-out portion of the electrode terminal and fixing the periphery of the hole with a heat resistant resin, the stability of the charging portion can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is a sectional view of the first embodiment of the present invention.

FIG. 3 is a perspective view of a PTC element.

FIG. 4 is a cross-sectional view of a joint portion between a PTC element and a metal pipe.

5 is a structural cross-sectional view of Example 1. FIG.

FIG. 6 is a structural cross-sectional view of a second embodiment.

FIG. 7 is a structural cross-sectional view of Example 6.

FIG. 8 is a cross-sectional view of a joint portion between a PTC element and a ceramic pipe in Example 6.

FIG. 9 is a structural cross-sectional view of Example 4.

FIG. 10 is a perspective view showing another example of the PTC element.

FIG. 11 is a perspective view showing still another example of the PTC element.

FIG. 12 is a perspective view of a heater when the element shown in FIGS. 10 and 11 is used.

FIG. 13 is a structural cross-sectional view of an example in which a metal base having a U-shaped cross section is used.

FIG. 14 is an enlarged perspective view of a tab structure terminal portion.

FIG. 15 is an enlarged perspective view around the lead-out portion of the terminal.

16 is a perspective view after a heat-resistant adhesive is attached in FIG.

17 is a sectional view taken along the line AA of FIG.

FIG. 18 is a structural cross-sectional view of a conventional heater.

FIG. 19 is a perspective view showing a conventional heating method.

[Explanation of symbols]

1 electrode plate, 2 PTC element, 3 metal pipe, 4
Heat resistant resin (silicone resin), 5 conductive adhesive, 6
Electrode layer, 7 Porcelain case, 8 Heated object, 9 Heater unit, 10 Heat resistant adhesive, 11 Switch, 12
Tab terminal, 13 holes, 14 insulating plate, 15 ceramic pipe

Claims (9)

[Claims] 1. A PTC pipe heater, wherein PTC elements are thermally bonded to n / 2 or more outer surfaces of an n-gonal metal or ceramic pipe, respectively. 2. The PTC pipe heater according to claim 1, wherein the material of the metal pipe is stainless steel. 3. The material of the ceramic pipe contains 50% by volume or more of alumina.
The PTC pipe heater described. 4. The PTC pipe heater according to claim 1, wherein at least one surface of the PTC element and the metal pipe are electrically insulated. 5. The PTC element or the joining portion between the electrode layer of the PTC element and the electrode plate is joined by a conductive adhesive, and the periphery thereof is fixed by a heat resistant resin. The PTC pipe heater according to 4. 6. The PTC pipe heater according to claim 1, wherein an elastic body is interposed between the in-pipe insert and the pipe. 7. The end portion of the electrode plate for applying a voltage formed on the PTC element has a tab structure.
7. The PTC pipe heater according to any one of to 6. 8. The electrode plate and the PTC element are fixed to each other by providing at least one hole around the terminal lead-out portion of the electrode plate and pouring a heat resistant resin into the hole. The PTC pipe heater according to any of the above. 9. A PTC pipe heater, wherein PTC elements are thermally bonded respectively to two opposing surfaces of a metal base having a U-shaped cross section.