JPH0528714Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a heater connected to a blower to generate hot air, and an electric heating element installed in the heater. The heater can also be incorporated into a hot air generator that integrates a blower and a heater. Furthermore, although the present invention was devised to generate hot air at a high temperature of approximately 1000℃,
Naturally, it can also be used when generating hot air at a temperature lower than this.

<Conventional technology> Conventionally, in order to generate hot air at a high temperature of about 1000°C, a large electric furnace was used, the required type of gas was fed into the electric furnace, and the gas was was circulated and heated to generate hot air. There are various types of electric furnaces, but basically they are equipped with heating wires such as nichrome wires inside the furnace. Figure 3 is a diagram of a conventional electric furnace, showing a heating chamber 2 lined with heat insulating material 1.
A heating wire 3 is installed inside the chamber, gas is supplied from a gas supply port 4, the gas is circulated and heated within the heating chamber, and hot air is discharged from a discharge port 5.

Heating with such an electric furnace has the following drawbacks.

The electric furnace is large and requires a large installation area.

The heat transfer efficiency from the heating wire to the gas is poor. That is, to obtain hot air of about 1000°C, the heating wire must be heated to about 1200°C, close to its melting temperature.

In addition, the thermal efficiency also deteriorates because the total volume of the heating section increases.

When high-pressure hot air is required, the intervention of a large heating chamber is very inconvenient to meet the requirement.

The installation cost is very high, and there are many inconveniences regarding equipment maintenance. For example, when a heating wire breaks, the workability of replacing it is poor.

On the other hand, as a heater for generating hot air up to about 600°C to 700°C, a heat insulating block is provided with several insertion holes for passing the gas to be heated.
There is one in which a heating wire is wired inside the insertion hole (No. 4).
(See figure, see Utility Model Application Publication No. 142493/1983). In FIG. 4, reference numeral 6 denotes a heat insulating block. Several through holes 7 for the gas to be heated are provided in the insulating block 6, and one heating wire 8 is wired through the through holes 7 in a zigzag pattern. The gas to be heated passes in the direction of the arrow in the figure and is heated.

In this conventional example, a problem occurs when hot air of 800° C. or higher is generated. That is, when hot air of 800° C. or higher is generated, the internal center and surface temperatures of the heating wire become extremely high, and the thermal conductivity decreases. To this end, one possibility is to increase the wire diameter of the heating wire to reduce the surface load (W/cm ² ) of the heating wire, but the heating wire material is already melted in the center of the heating wire. There is a drawback that the melted heating wire material flows out from pinholes etc. on the surface of the heating wire. Furthermore, although the life of the heating wire is naturally shortened, it is very troublesome to replace the heating wire when the wire breaks or the like, and maintenance is poor. Furthermore, since the heating wires are used at high temperatures, steam generated from the heating wires adheres to the inner wall of the heating gas insertion hole, which causes the lifespan of the heating wires after replacement to extend beyond the lifespan of the heating wires that were originally installed. It has been empirically proven that the heating time is shorter than that of the heater itself, and eventually the lifespan of the heater itself is exhausted, which poses a problem in terms of durability.

<Problems to be solved by the invention> In order to solve the problems existing in the conventional heaters described above, the problems to be solved by the present invention are as follows.

Generate high-temperature hot air of approximately 1000℃ using a small device rather than a large one such as an electric furnace.

To most efficiently exchange heat from an electric heating wire to a gas to be heated while minimizing heat loss to the outside, etc.

Since high-temperature hot air is generated, the heating wire itself has a limited lifespan, and the heating wire should be constructed so that it can be easily replaced in the event of a breakage. This improves maintainability.

Furthermore, the durability of the heater itself can be improved by simply replacing heating wires, etc.

It is an object of the present invention to provide a heater and an electric heating element for realizing the above-mentioned problems.

<Means for Solving the Problems> In order to solve the above problems, the present invention covers the outer periphery of the conductive support rod 10 with a heat-resistant insulator 11,
A heating wire 12 such as a nichrome wire connected to one end of the conductive support rod 10 is wound around the heat-resistant insulator 11, and a terminal 13 is connected to the other end of the conductive support rod 10.
An electric heating element having a terminal 14 of a heating wire 12 disposed on the side thereof is connected to one or more insertion holes 1 provided in the heat insulating block 17 for passing the gas to be heated.
The conductive support rod 10 and the heating wire 12 are connected at both ends. Child 13,1
4 is arranged on the gas supply port side of the through hole 18 for the heated gas, and the electric heating element and the heat-resistant insulating tube 19
can be installed and removed from the gas supply port side.

<Function> By supporting the spirally wound heating wire 12 at its center by the conductive support rod 10, the blown gas absorbs heat from inside and outside of the spiral heating wire 12.

In the event of a break in the heating wire, the entire heating element can be easily removed from the heater and replaced. At this time, the electric heating element and the heat-resistant insulating tube 19 interposed on the inner surface of the insertion hole 18 can also be easily replaced from one side at the same time.

<Example> An example will be described below based on the attached drawings. FIG. 1 is a partially omitted explanatory diagram illustrating the structure of an embodiment of the present invention.

First, the structure of the electric heating element will be explained. Reference numeral 10 denotes a conductive support rod made of a nickel rod, and the entire outer circumference of the conductive support rod 10 except for both ends is coated with a heat-resistant insulator 11. As the heat-resistant insulator 11, a cylindrical tube made of alumina, mullite, or the like is used, and the conductive support rod 10 is inserted into the tube. A heating wire 12 made of nichrome wire or the like is connected to the right end of the conductive support rod 10 in the figure, and the heating wire 12 is wrapped around the heat-resistant insulator 11 toward the left in the figure. Wind. Then, the terminal 13 of the conductive support rod 10 and the terminal of the heating wire 12 are arranged on the same side.
The heating wire 12 is supported by a conductive support rod 10 and the heating element is attached to the cover 15 of the heater. The total length of the electric heating element is approximately 1100 mm in this example.

FIG. 2 is a perspective view of the electric heating element, in which the conductive support rod 10 is connected to a cylindrical heat-resistant insulator 11.
the heating wire 1 at one end of the support rod 10.
2, and the heating wire 12 is wound spirally around the heat-resistant insulator 11 from the upper right to the lower left in the figure. The conductive support rod 10 and the terminals 13 and 14 of the heating wire 12 are arranged on the same side. The winding density and helical diameter of the heating wire 12 can be set arbitrarily, and can be determined to match the desired hot air generation temperature.

Next, returning to FIG. 1 and explaining the heater, reference numeral 16 is a cylindrical heater case, and the heater case 16 has an insertion hole in the center through which the gas to be heated passes. A heat insulating block 17 is constructed by stacking the provided cylindrical heat insulating insulators (not shown). Therefore, insulation block 1
7 has an insertion hole 18 through which the heated gas can pass.
is formed. A cylindrical heat-resistant insulating tube 19 is inserted into the insertion hole 18 so as to be in contact with the inner surface of the insertion hole 18, and fixed to the heat insulation block receiver 20. The heat-resistant insulating tube 19 is made of the same material as the heat-resistant insulator 11 of the conductive support rod 10. Then, the electric heating element is inserted into the heat-resistant insulating tube 19 from the heating gas supply port 21 side and fixed to the cover 15. With this configuration, the heat-resistant insulating tube 19 and the electric heating element can be easily replaced from the side of the supply port 21 for the gas to be heated.

In the heater configured as described above, gas blown from a blower or the like is sent from the supply port 21 into the heat-resistant insulating tube 19 fitted into the insertion hole 18, heated by the heating wire 12, and discharged. Exit 22
High-temperature hot air can be discharged from.

23 is a temperature sensor that senses the temperature of the discharged gas, and although not shown, the heat-resistant insulator 11
Temperature sensors are also installed at appropriate positions so that the surface temperature of the heating wire 12 can also be sensed.

The total length of the heater in this example is approximately 1200 mm.

Although one embodiment has been described above, the material, dimensions, etc. of each component can be determined as appropriate, and the number of insertion holes 18 provided in the heat insulation block 17 can also be set arbitrarily. It is possible to manufacture heaters with large capacities.

<Effects of the invention> The present invention having the above configuration has many effects as follows.

Compared to an electric furnace, it is very small and only about
It can generate high-temperature hot air of 1000℃, does not require a special installation location, and can reduce equipment costs.

By placing an electric heating element in the insertion hole, the blowing gas is forced to pass over the entire surface of the heating wire, maximizing thermal efficiency and reducing the surface temperature of the heating wire and the heated gas. It was possible to reduce the difference between the temperature of Also,
Heat loss could also be reduced by downsizing the heater.

In conventional heaters, the heating wire was directly supported in the insertion hole provided in the insulation block, but in the present invention, the heating wire is supported on the conductive support rod, so the heating element can be integrated into one unit. It became possible to make the electric heating element into parts, which made it possible to easily attach and remove the electric heating element from the heater body, making it easy to replace it and improving maintenance of the device. This ensures the durability of the heater itself.

A heat-resistant insulating tube is inserted into the insertion hole provided in the insulation block, and the steam generated from the heating wire due to high-temperature heating adheres to the inner surface of the tube, adversely affecting the durability of the heating wire. However, since the heat-resistant insulating tube can be easily replaced, its adverse effects can also be eliminated as appropriate. This further improves the durability of the heater.

Both the electric heating element and the heat-resistant insulation tube can be easily installed and removed from the same direction on the supply port side of the heater. This improves maintainability. This effect occurs in heaters that generate high-temperature hot air of around 1000℃.
Considering that heating wires have a limited lifespan and must be replaced, this is a very significant effect.

As described above, the present invention has a simple structure and exhibits great effects.

[Brief explanation of the drawing]

Fig. 1 is a partially omitted structural explanatory diagram showing a heater that is an embodiment of the present invention, Fig. 2 is a perspective view similarly showing an electric heating element, and Fig. 3 is an explanatory diagram of a conventional electric furnace. , FIG. 4 is a perspective view of a conventional heater. Codes in the figure: 10... Conductive support rod, 11... Heat resistant insulator, 12... Heating wire, 13, 14... Terminal, 17... Heat insulation block, 18... Insertion hole, 1
9...Heat-resistant insulation tube.

Claims (1)

[Scope of utility model registration request] The outer periphery of the conductive support rod 10 is covered with a heat-resistant insulator 11, and a heating wire 12 such as a nichrome wire connected to one end of the conductive support rod 10 is covered with the heat-resistant insulator 11.
An electric heating element, in which the terminal 14 of the heating wire 12 is arranged on the side of the terminal 13 at the other end of the conductive support rod 10, is connected to an electric heating element provided in the heat insulating block 17 for passing the gas to be heated. Or each is provided in two or more insertion holes 18, and furthermore, the insertion holes 1
The conductive support rod 10 and both terminals 13 and 14 of the heating wire 12 are inserted into the heating gas insertion hole. A heater for generating hot air, characterized in that the electric heating element and the heat-resistant insulating tube 19 are arranged on the gas supply port side of the gas supply port 18 and can be attached and detached from the gas supply port side.