JPS6042406B2 - thermography equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermography device suitable for use when observing the inside of a furnace through a window provided in the side wall of the furnace, for example.

Recently, a window has been installed on the top or wall of a steelmaking blast furnace, and a thermography device is used to photograph the surface temperature distribution image inside the furnace through the window. Control is being done.

Ru. The inside of a furnace is generally high temperature and pressure, and there is dust floating around inside the furnace, making the windows extremely dirty.

Therefore, we use high-pressure gas to blow away the dust that has adhered to the windows.
It is necessary to attach a cleaning device to the window that can be washed away with a cleaning solution. If the window is small, the cleaning device can be small, but in reality it was necessary to secure a field of view inside the furnace for controlling the furnace, so the window had to be sufficiently large. The expensive infrared transmitting window material (silicon Q + day,...)
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, −−゛, the size had to be increased, which was disadvantageous in terms of price. Furthermore, if the entire window is not cleaned uniformly, the transmittance will decrease in certain areas of the field of view, resulting in uneven images, so cleaning becomes technically more difficult as the size of the window increases. The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a thermography device that can observe a large field of view with a small window area, and can therefore miniaturize the cleaning device. It is.

The present invention will be explained in detail below using the drawings. FIG. 1 shows the structure of an embodiment of the present invention, in which 1 is a furnace wall, 2 is an infrared transmitting window provided on the furnace wall, and 3 is an optical scanning mechanism.

For example, as shown in FIG. 2, the scanning mechanism 3 is composed of a truncated pyramid-shaped x-direction scanning mirror M that rotates around an axis J, and a Y-direction scanning mirror M2 disposed above it. Two lenses 4 and 5 forming an afocal system are arranged between the scanning mechanism 3 and the window 2. The infrared rays are extracted from the window 2 through the transmission lenses 4 and 5, scanned and focused by the scanning mechanism 3, and sent to the detector 7 through the lens 6, where they are detected. In the above-described configuration, the x-direction deflection points of the scanning mechanism 3 substantially coincide with each other.

That is, since the corner of the scanning mirror is rotated back and forth about the axis o as appropriate, the deflection point in the Y direction is aligned with the point P near the mirror surface of the scanning mirror M, which is the deflection point in the X direction, as shown in FIG. We are doing so. The lenses 4 and 5 constituting the afocal system are
, the Y-direction deflection point P is placed at or very close to the focal position of the lens 4, and the window 2 is placed at or very close to the focal position of the lens 5. Therefore, X, Y
An image P'' of the direction deflection point P is formed at the center of the window 2, and it can be considered that the X and Y direction deflection points have substantially moved to P''. In this way, the window area required for the X and Y direction deflection points to be at the positions of the windows 2 is extremely small, making it possible to reduce the amount of expensive silicon windows used and also requiring a small cleaning device. Furthermore, if a large window cannot be provided due to strength issues, a wider field of view than before can be secured even with a small window. In the above-described embodiment, a scanning mechanism in which the X and Y direction deflection points coincide is used, but the invention is not limited to this, and even if the X and Y direction deflection points are different, one of the deflection points, for example, the X direction deflection point, is set to the lens 4. The present invention can be carried out by placing the focal point at the focal position.

However, in that case, since the Y-direction deflection point does not move to the window position, it is not possible to expect the window width to decrease in the Y-direction. It is also possible to configure each of the lenses 4 and 5 by combining a plurality of lenses.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of one embodiment of the present invention.
The figure is a diagram showing an example of an optical scanning mechanism. 1: Furnace wall, 2: Infrared transmission window, 3: Optical scanning mechanism, 4
, 5, 6: Lens, 7: Infrared detector.

Claims (1)

[Claims] 1. A thermography apparatus comprising a detector for detecting infrared rays extracted through an infrared transmitting window and an optical scanning means for scanning the infrared flux incident on the detector, wherein the optical scanning means and a window, at least two lenses constituting an afocal system are arranged, and the focal position of one lens is made to substantially coincide with the deflection point in the X direction and/or the deflection point in the Y direction of the optical scanning means, and the other lens A thermography apparatus characterized in that the window is arranged at or near a focal point position.