JPS63255650A - Apparatus for detecting abnormality of inner wall part of high temperature container - Google Patents

Abstract

PURPOSE:To reduce the effect of wind and to enhance the detection accuracy of abnormality, by providing an infrared camera, a filter device and a memory device. CONSTITUTION:An infrared camera 1 is driven by a camera controller 2 to pick up the image of the outer surface of a high temp. container. The infrared image signal is subjected to addition averaging processing by an image smoothing device 3 to synthesize one digital image data. Further, the image data is passed through a filter device 10 to analyze frequency and, after low frequency component is cut by said device, said image data is inversely converted to re-synthesize the image. By this processing, the effect of wind is reduced. At the rising time of a plant, a reference signal preliminarily synthesized by the same processing is recorded on an image memory apparatus 7. A comparator 4 operates the difference between the reference image recorded on the apparatus 7 and the image data from the filter device 10. At this time, since the direction of a wind is irregular, this processing is repeated several times to synthesize a plurality of the image data of the difference with the reference image and said image data are subjected to additional averaging processing by a image smoothing processor 11. Further, the image data are differentially operated by a differentiation operator 5 and a flaw is judged by a flaw judge processor 6 to judge the kind, position and degree of abnormality to display the same.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting an abnormality on the inner wall of a high-temperature reaction vessel in major plants such as oil refining and chemical manufacturing, cement and steel manufacturing plants, and the like.

[Conventional technology]

Conventionally, abnormalities in the inner wall of a high-temperature container are inspected by completely stopping the operation of the high-temperature container during periodic maintenance, and having an inspector enter the container and visually inspect the container or perform a hammer test. However, since production is zero while the plant is out of service, the longer the regular maintenance period is, the greater the economic burden and losses will be.

Therefore, in application No. 11-21751, we proposed an abnormality detection device that can detect abnormalities in high-temperature containers during plant operation. This device is based on the phenomenon that when castable VC abnormalities (abrasion, peeling, cracks, etc.) occur on the inner wall of a high-temperature container, the heat transfer characteristics from the inside to the outer wall of the container change. Monitors the entire temperature distribution of the outer wall, detects temperature changes, and diagnoses abnormalities on the inner wall.

The outline will be explained below based on FIG. 2. A camera controller 2 drives an infrared camera 1 to photograph the entire outer wall of a high-temperature container, and an image smoother 6 performs averaging processing on a plurality of image data.

On the other hand, when the plant is started up in advance (when the inner walls are normal), similar image data is combined to form a reference image and recorded in the image memory device 7.

Therefore, the comparator 4 calculates the difference between the reference image recorded in the image memory device 7 and the average image of the FfB image smoother 3, and detects temperature distribution points different from the reference image. Furthermore, the differential calculator 5 emphasizes points where there is a local temperature difference, and the defect determination processor 6 displays the abnormality after determining the type and degree of the abnormality.

When this device is applied, all abnormal points on the inner wall of a high-temperature container can be identified during plant operation, so periodic repairs can be carried out efficiently and the repair period can be shortened.

[Problem that the invention seeks to solve]

The surface temperature distribution of the outer wall of a high-temperature container obtained with an infrared camera does not change only due to the occurrence of defects, but also due to disturbances such as weather conditions (wind, rain, temperature, etc.) and dirt on the outer surface of the container. also changes. On the other hand, the temperature change on the outer wall surface caused by an abnormality in the inner wall generally correlates with the degree of the abnormality. Therefore, if the degree of abnormality is small, the temperature change on the outer wall surface may be hidden by the temperature change due to disturbance and cannot be detected.

The present invention aims to provide an abnormality detection device for the inner wall of a high-temperature container, which reduces the influence of wind, which has the most negative effect on the temperature distribution on the outer wall surface among disturbances, and improves abnormality detection accuracy compared to conventional methods. That is.

[Means for solving the problem] The present invention consists of an infrared camera that two-dimensionally grasps the temperature distribution t on the outer wall of a high-temperature container, a smoother that smoothes the image signal of the camera, and a skeleton smoother. a filter device that removes a specific spatial frequency component of the image data; a memory device that stores all the image data when the V3 wall of the high temperature container is normal; a comparison device that compares the two image data; and an addition of the image data. This is an abnormality detection device for an inner wall of a high-temperature container, characterized by having an arithmetic device that performs differentiation and/or differentiation, and a defect determination processing device that identifies and displays all types and degrees of abnormalities.

[Effect]

The effect of wind on heat transfer on the wall surface is explained in full (see Figure 6).

According to heat transfer analysis calculations, when wind hits a certain plane 8 perpendicularly (FIG. 3(a)), the temperature of the plane decreases as the wind speed increases (FIG. 3(b)).

Furthermore, assuming that the temperature distribution on the side surface of the cylindrical object 9 is uniform in a windless state (Fig. 3 (C)), when the wind blows, the temperature on the parallel surface decreases more than on the perpendicular surface (Fig. 3 (C)). 3
For this reason, if the wind direction is constant, the influence of the wind (wind direction in percent) can be reduced by performing a spatial frequency analysis of the temperature distribution and removing the low frequency components.

By the way, the direction of the natural wind is often stable for a period of several minutes to several hours. However, the strength of the wind is constantly changing. On the other hand, in the long term, the wind direction changes depending on the weather (air pressure distribution), so for short-term data (several minutes to hours), it is necessary to obtain the spatial frequency spectrum of the temperature image and cut the low frequency components. It is possible to reduce the influence of wind (wind direction and speed) on the temperature distribution on the outer wall surface. Furthermore, in the long term, the effects of irregular winds can be further reduced by averaging the data obtained through multiple short-term processes.

〔Example〕

The present invention will be described in detail below with reference to FIG.

The infrared camera controller 2 controls the infrared camera 1.
is driven to photograph the outer surface Wi of the high-temperature container. Infrared image signal for about 3 to 5 minutes with image smoother 3? Addition and averaging processing is performed to synthesize one digital image data. A filter device 10 performs frequency separation on the image data, cuts low frequency components, and performs inverse transformation to recombine the image. This process can reduce the influence of wind. On the other hand, the image memory device 7 is stored in advance when the plant is started up (if the inner walls are normal).
A reference image processed and synthesized in the same manner as above is recorded.

Therefore, the comparator 4 calculates the difference between the reference image recorded in the mi image memory device 7 and the image data from the filter device &10. Since the wind direction is irregular from a long-term perspective,
By repeating the above process multiple times (over several days), multiple images of difference image data from the reference image are combined, and the image smoother 1
1 performs additive averaging processing.

This is because a temperature difference in the reference image caused by an abnormality on the inner wall of the high-temperature container always appears at a specific point, whereas a temperature difference caused by the influence of wind appears at irregular points.

Further, when processed by the differential calculator 5, abnormal points can be emphasized. The defect determination processor 6 determines and displays the type, position, and degree of abnormality based on the above results.

〔Effect of the invention〕

By adopting the above configuration, the present invention makes it possible to remove temperature change components due to the influence of wind and accurately detect temperature changes caused by abnormalities on the inner wall of a high temperature container.
This has a great effect on shortening the period of plant downtime for regular repairs.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an abnormality detection device for the inner wall of a high temperature container according to the present invention, Fig. 2 is a block diagram of a conventional device, and Fig. 3 is a diagram for explaining the influence of wind on heat transfer on the wall surface. Aya in the diagram,
In Figure 5, (a) is a diagram of the relationship between the wind and the plane, and (b) is (a)
(C) is a temperature distribution diagram of the A A' coating surface of the cylinder in a windless state, and (d) is a diagram of the B B' coating surface temperature distribution diagram of the cylinder when there is K.

Claims (1)

[Claims] an infrared camera that two-dimensionally grasps the temperature distribution on the outer wall of the high-temperature container; a smoother that smoothes the image signal of the camera;
a filter device that removes a specific spatial frequency component of the image data from the smoother; a memory device that stores image data when the inner wall of the high temperature container is normal; and a comparison device that compares the two image data; 1. An abnormality detection device for an inner wall of a high-temperature container, comprising an arithmetic unit that adds and/or differentiates image data, and a defect determination processing device that identifies and displays the type and degree of an abnormality.