JP2572182B2 - Far infrared heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a far-infrared heating apparatus, and is applied to, for example, a drying apparatus for removing water from raw materials and molded articles.

[0002]

2. Description of the Related Art In general, a radiant heating type drying apparatus using far infrared rays is known as a drying apparatus for raw materials such as ceramics and molded articles. This type of drying apparatus has a ceramic heating element at a predetermined position in a drying chamber, and heats the object to be heated by far infrared rays emitted from the ceramic heating element. Conventionally, as a ceramic heating element, a kind of ceramic heating element having a radiation region at a predetermined wavelength has been used.

[0003]

However, when the object to be heated is dried by such a conventional far-infrared heating device, if the temperature of the object to be heated and the amount of water retention change during the heating process, the infrared ray of the object to be heated is changed. Absorption intensity characteristics change every moment.
For this reason, when the difference between the infrared radiation wavelength region of the ceramic heating element and the infrared absorption wavelength region of the object to be heated is relatively small, the object to be heated is efficiently heated. When the difference from the above is large, there is a problem that the heating efficiency of the object to be heated is reduced and power consumption is likely to be large.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a far-infrared heating apparatus which can efficiently and quickly dry an object to be heated with low power consumption. I do.

[0005]

A far-infrared heating apparatus according to the present invention for solving the above-mentioned problems is provided with a plurality of ceramic heating elements which are arranged so as to irradiate far-infrared rays to an object to be heated and which have different emission wavelength ranges from each other. A detecting device for detecting a wavelength indicating a predetermined infrared absorption intensity of the object to be heated, and at least one ceramic of the plurality of ceramic heating elements so as to have a maximum thermal efficiency based on an output signal of the detecting device. And a control device for selectively energizing the heating element.

[0006]

According to the far-infrared heating device of the present invention,
With the change of the infrared absorption characteristic of the object to be heated, the detection device detects the wavelength indicating the maximum infrared radiation intensity of the object to be heated as needed. Next, the control device selects a ceramic heating element that emits a wavelength having a relatively high infrared absorption efficiency. Therefore, the object to be heated dries efficiently and in a short time.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a far-infrared heating device 1 dries a heated object 2 made of a ceramic molded body or the like.
Ceramic heater 3 for irradiating the object to be heated 2 with far infrared rays
a, 3b, 3c, a detection device 4 for measuring a wavelength indicating the maximum infrared absorption intensity of the object 2 to be heated, and ceramic heaters 3a, 3
b, 3c and a control device 5 for selectively outputting an energization signal. When the object to be heated 2 is arranged at a predetermined position in the drying chamber and, for example, a timer or the like is set, the ceramic heater 3a,
The object to be heated 2 by far infrared rays emitted by 3b and 3c
Is heated until a predetermined amount of water is retained.

The ceramic heaters 3a, 3b, 3c
i quality, MoSi ₂ quality, LaCrO ₃ quality, ZrO ₂ quality, T
hO ₂ , BaTiO _3, and other semiconductive ceramics. As shown in FIG. 2, far-infrared wavelengths λ _a , λ _b , λ showing the maximum infrared radiation intensity at the same temperature T ° C.
_c is gradually different. That is, the ceramic heaters 3a, 3b, and 3c each have a relatively short wavelength range,
The infrared radiation intensity is set to be large in a medium wavelength region and a relatively long wavelength region.

The detecting device 4 detects the infrared absorption characteristic of the object 2 at predetermined time intervals. Specifically, a dispersion type spectrophotometer, a Fourier transform infrared spectrophotometer, a filter type spectrophotometer, or the like can be used. In this case, for example, far-infrared rays having a wavelength of 1 μm to 1000 μm are radiated to the object to be heated 2 instantaneously, and the absorptance of each wavelength is measured. Then, a wavelength indicating the maximum infrared absorption intensity of the object to be heated 2 is detected, and this detection signal is transmitted to the control device 5.

A control device 5 electrically connected to each of the ceramic heaters 3a, 3b, 3c performs an arithmetic process on a detection signal from the detection device 4, and the ceramic heater 3a, which has a relatively large heating efficiency with respect to the object 2 to be heated. 3b and 3c are selected. At the time of heating, as shown in FIG. 2, when the infrared absorption wavelength region of the object 2 changes in the direction of arrow d in FIG. 2, the ceramic heaters 3a, 3b, and 3c are sequentially energized. in this case,
For example, a wavelength λ indicating the maximum infrared absorption intensity of the heating target 2
_{When d} exceeds the wavelength λ _{e at} which the infrared radiation intensities of the ceramic heaters 3a and 3b become equal, the ceramic heater 3a is switched to the ceramic heater 3b. Also, when more than a wavelength lambda _f of the wavelength lambda _d infrared radiation intensity of the ceramic heater 3b and 3c are equal, it switched from the ceramic heater 3b to the ceramic heater 3c.

As described above, according to the infrared heating apparatus 1 of the embodiment, the ceramic heaters 3a, 3b, and 3c that heat the object to be heated 2 most efficiently according to the change in the infrared absorption characteristics of the object to be heated. Selected. For this reason, while the drying time of the to-be-heated body 2 is shortened, the power consumption of the ceramic heaters 3a, 3b, 3c can be reduced significantly.

In the above embodiment, the ceramic heater 3a,
Although the configuration is such that 3b and 3c are sequentially switched, according to the present invention, a plurality of ceramic heaters may be energized at the same time in order to prevent a reduction in the amount of infrared radiation absorbed by the object to be heated.
In addition, when a ceramic heater is selected, the relationship between the weight change due to the evaporation of water in the object to be heated and the maximum infrared absorption wavelength is measured in advance by an experiment, so that the infrared ray can be calculated from the weight change value measured by the detection device. It is also possible to estimate the absorption characteristics and select a ceramic heater so that the infrared absorption amount is maximized.

[0013]

As described above, according to the far-infrared heating apparatus of the present invention, the ceramic heater for heating the object to be heated with relatively high efficiency in accordance with the change in the infrared absorption characteristics of the object to be heated is selectively used. Therefore, the object to be heated can be quickly dried with low power consumption, and there is an effect that energy saving of the drying device can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a far-infrared heating device according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a wavelength of far infrared rays, an infrared radiation intensity, and an infrared absorption intensity according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Far-infrared heating device 2 Heated body 3a, 3b, 3c Ceramic heater (ceramic heating element) 4 Detector 5 Controller

Claims (1)

(57) [Claims] 1. A plurality of ceramic heating elements which are arranged so as to be able to irradiate far-infrared rays to an object to be heated, and which emit different far-infrared wavelengths from each other;
A detection device that detects the maximum infrared absorption wavelength at any time by measuring the long absorption rate , based on the output signal of the detection device, the maximum red of the object to be heated
At maximum infrared radiation intensity at external absorption wavelength
And a control device for selectively energizing at least one or more of the plurality of ceramic heating elements.