JPH02143093A - High temperature section monitoring device - Google Patents

Abstract

PURPOSE:To make a scanning device unnecessary and improve the reliability of a facility by a method wherein a means, reflecting and collecting infrared rays radiated from the element of a heat exchanger by a reflecting plate opposing to the end face of the element and detecting them at the outside of a side surface, is provided in the title monitoring device. CONSTITUTION:A belt type concave reflecting plate 3 is provided along a place including the rotary shaft 16 of the reflecting plate 3 so that the reflecting surface thereof is opposed to the end face of a metallic fin 15. Further, the configuration of the reflecting plate 3 is formed so that infrared rays, coming from the fin 15 in parallel to the shaft 16, are collected at the upper part of the outside surface of the fin 15. An infrared rays sensor 4 is provided at the outside of a duct near the focus of the infrared rays sensor 4. The infrared rays, advancing straightly through the gap of the fin 15, are collected at the focus by the reflecting plate 3. The sensor 4 detects the infrared rays and can know the temperature of which fin 15 is abnormally high. According to this method, mechanical scanning becomes unnecessary and movable parts are eliminated whereby the reliability of a facility may be improved.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a high temperature part monitoring device such as an air preheater.

[Prior Art] A conventional device will be explained with reference to FIGS. 3 to 6. FIG. 3 is a perspective view of the configuration of a radial, rotary heat exchange element type air preheater, and FIG. 4 is a plan view of an infrared sensor section. FIG. 5 is a side view of the infrared sensor section, and FIG. 6 is a perspective view of the infrared sensor section.

In FIG. 3, there are many metal fins inside, namely:
The cylinder 11 in which the heat exchange elements 15 are arranged radially is
The drive electric motor 12 rotates at a low speed (Irρn
degree). Further, on both end faces of the cylinder 11, there are provided first system ducts 7, 18 and second system ducts H9, 20 which face each other and divide the end face into two.

With the above configuration, for example, high-temperature gas (for example, exhaust gas in a thermal power boiler) is flowed in the directions of arrows A and A' using the duct [9 of the second system] as the inlet and the duct 20 as the outlet. As a result, the metal fins that come into contact with this gas are heated. As the cylinder 11 rotates, the heated fins are transferred from the middle of the ducts H9 and 20 to the first system of ducts [7, 1].
It comes in the middle part of 8. Arrows B and B' on this duct
When the air to be heated flows in the direction, the air comes into contact with the metal fins 15 heated by the high-temperature gas, and the air is heated. This is the principle of the Ljungström type air heater. In the air heater having this configuration, for example, if the exhaust gas contains unburned matter, it will accumulate in the gaps between the metal flasks, sometimes leading to rapid combustion. In order to prevent this from happening, it is necessary to discover abnormally high temperature areas.

In Figures 4 and 5, a method of detecting infrared rays generated from this high temperature area and emitted from the gaps between the metal fins 15 to discover the high temperature area has been conventionally used as one of the high temperature area monitoring methods. There is. The infrared sensor 21 has a metal fin 15
and is attached to the rotating arm 22. This rotary arm swings left and right along the end face by the drive unit 23, and covers the metal fin 15 in the radial direction.

Further, these are housed in a duct 19.

FIG. 6 shows the relationship between the infrared sensor 21 and the metal fin 15, and the infrared rays seen between the metal fins 15 as indicated by arrow d are transmitted through the lens 2 attached to the front of the infrared sensor 21.
4 and enters the sensor element 25.

[Problem to be solved by the invention]

As explained above, the conventional device has the following problems.

(1) Infrared rays from the high-temperature part of the air preheater come out through the narrow gaps between the metal fins, so if there is no sensor directly above the metal fins, that is, above the end surface, the sensitivity will be extremely low. Therefore, in order to monitor each metal fin in its entirety, it is necessary to scan in the radial direction even with the aid of the rotating metal fins. .

(2) Therefore, a scanning device is required, and the scanning device is installed inside the duct.

(3) Also, in the scanning device method, detection is delayed by the time it takes to scan.

(4) Maintenance of sensors and scanning devices is difficult inside the duct.

(5) Although not shown or explained, movable piping and wiring for sensor cooling etc. are required, which poses a problem in durability.

(Means for solving problems) The present invention takes the following measures to solve the above problems.

In other words, in an air preheater having a rotating heat exchange element arranged in a radial shape, a strip-shaped concave reflector is provided along a plane containing the rotation axis of the heat exchange element and facing the end face of the heat exchange element. a plate, and a means for sensing infrared rays reflected and condensed by the reflecting plate, and the reflecting plate detects the infrared rays radiated from the heat exchange element section in parallel to the rotation axis to the outside of the side surface of the heat exchange element. I tried to gather them in the same direction.

(Function) With the above means, when an abnormally high temperature occurs in the air preheater, infrared rays from the gap along the radial direction of the heat exchange element are collected by the reflection plate to the outside of the side surface of the heat exchanger element 1a, and the detection means In this way,
By installing infrared detection means outside the duct, abnormal high temperatures can be easily detected in real time without mechanical scanning.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

Note that the description of the portions described in the conventional example will be omitted to avoid redundancy, and the description will mainly focus on the portions related to the present invention.

In FIGS. 1 and 2, the strip-shaped concave reflecting plate 3 is provided along a plane including the rotating shaft 16, with its reflecting surface facing the end face of the metal fin 15. Further, the shape of the reflector 3 is formed so that the infrared rays emitted from the metal fin 15 in parallel to the rotation axis 16 are collected above (outside) the outer surface of the metal fin 15. duct] - provided outside the duct.

In the above configuration, as shown by the dotted line, the metal fin 15
The infrared rays that go straight through the gap are reflected by the reflector 3,
be focused on that focus. The infrared sensor 4 detects the infrared rays and can know which metal fin 15 is experiencing an abnormally high temperature. Therefore, it is possible to take measures such as cooling the abnormally high temperature area by pouring water on it.

In the above, an infrared camera may be arranged instead of the infrared sensor 4. At this time, an image of the metal swing 15 is captured by an infrared camera, and the intensity distribution of the infrared rays can be displayed on a TV or the like. metal fin 15
Since the length is 5 to 6 meters, if an abnormal temperature in a part is found, that part can be cooled by pouring water on it to prevent the unburned matter attached to it from burning.

〔Effect of the invention〕

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

(1) Since the infrared sensor or infrared camera is fixed and installed outside the duct, maintenance is easier.

(2) Mechanical scanning is not required and there are no moving parts, improving reliability.

(3) High-temperature areas in radial rows can be monitored simultaneously in real time. Further, if a fire extinguishing means is provided, combustion after detection can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is a plan view of the same embodiment, Fig. 3 is a perspective configuration diagram of an air preheater of a conventional device, and Fig. 4 is an infrared ray of the same conventional device. FIG. 5 is a plan view of the sensor section, FIG. 5 is a longitudinal sectional view of the infrared sensor section of the conventional device, and FIG. 6 is a perspective view of the infrared sensor section of the conventional device. 3 reflector, 4 red line sensor or infrared camera, 11 cylinder, 15 heat exchange element (metal fin). Agent: Patent Attorney Akigai Sakama (2 people) Figure 2 Figure 4 Figure 6

Claims (1)

[Claims] In an air preheater having heat exchange elements arranged radially and rotating, a band-shaped concave reflector plate provided along a plane including the rotation axis of the heat exchange element and facing the end face of the heat exchange element; means for sensing infrared rays reflected and focused by a reflector, the reflector concentrating infrared rays emitted from the heat exchange element section in parallel to the rotation axis to the outside of a side surface of the heat exchange element. A high temperature part monitoring device featuring: