JPS6288932A - Detecting device for liquid leak in container - Google Patents

Abstract

PURPOSE:To compare the quantities of passed light of both filters with each other and to detecting a liquid leak in a container from the comparison result by providing an infrared detecting element array with the 1st and the 2nd filters for light in a wavelength band which is hardly absorbed by specific liquid and light in a wavelength band which is easily absorbed. CONSTITUTION:The weld zone 11 of the container 10 is irradiated with rays of light from a light source 20, rays of light reflected by the weld zone 11 are received by the photodetection end surface 31 of an optical fiber array 30, and rays of light passed through the array 30 rare projected from a projection end surface 32. This projected rays of light are made incident on a visible light sensor array 70 through an image forming lens 41 and a dichroic mirror 42. A rotary disk 50 is provided on the optical path between the dichroic mirror 42 and the memory 61 of the photodetecting element array. This rotary disk 50 is provided with the 1st filter 51 for the wavelength band which is easily absorbed by the specific liquid and the 2nd filter 52 for the wavelength band which is hardly absorbed. The quantities of rays of light passed through the filters 51 and 52 are compared with each other by a comparing circuit connected to the memory 61 to detect a liquid leak in the container 10 from the weld zone 11.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a container liquid leak detection device.

[Prior Art] Currently, a CCD camera is used to detect a liquid leakage in a long (e.g., 30 mm width) weld of a large tank (e.g., 25 m diameter).
About 00 images were created and analyzed. However, this method requires a human to directly view and analyze all 1,000 images with their eyes, so there is a problem in that the analysis takes a very long time.

[Object of the Invention] The present invention has been made by focusing on the above-mentioned prior art, and an object of the present invention is to provide a liquid leakage detection device for a container that can automatically detect liquid leakage from a container. It is.

[Embodiment of the Invention] FIG. 1 is an explanatory diagram showing an embodiment of the present invention.
The figure is a perspective view showing the container 10 and the welded portion where liquid leakage is to be detected.

A light source 20 is provided at a position to irradiate light onto the welded part 11 of the container 10 shown in FIG. 3, and an optical fiber array 30 is provided at a position to receive the light reflected by this light source 20. -30 is a small diameter (for example, 1 diameter
A large number of optical fibers (of TARs) are arranged, and the light-receiving end face 31 of the array 30 is
The light received by

It comes out from the injection end face 32.

The imaging lens 41 forms an image of the light that has passed through the optical fiber array 30 on the light receiving element array 60. The guichroic mirror 42 reflects only infrared rays and sends the reflected light to the light receiving element array 60.

The rotating plate 50 includes a first filter 51 and a second filter 52.
and rotates them. The first filter 51 is a filter that passes infrared rays in a wavelength band that is easily absorbed by a predetermined liquid (for example, water), and the second filter 52 is a filter that passes infrared rays in a wavelength band that is difficult to be absorbed by the liquid. be. In other words, the first filter 51
．． The second filters 52 are each a type of bandpass filter.

The rotating plate 50 reflects the light from the light source 20 on the predetermined container 10, and the reflected light travels along the optical path toward the light receiving element array 60.
This is one of the chopping means that chops light by crossing the first filter 51 and the second filter 52 alternately.

Note that the visible light sensor array 70 is a sensor that detects an image of the welding part 11.

In addition, in FIG. 1, the welding part 11 is moved (
Although the container 10 is depicted as rotating), in reality, if the container 10 is large, the light source 20 and the optical fiber array 30 will simultaneously move relative to the container 10. . However, the light source 20, the optical fiber array 30, and the container 10 only need to be moved relative to each other.

FIG. 2 is a block diagram showing an example of signal processing in the first embodiment.

The memory 61 temporarily stores the signal from the light receiving element array 60, and when the first filter 51 crosses the optical path between the gicroic mirror 42 and the light receiving element array 60, It stores the output signal of the light receiving element array 60. That is, the memory 61 stores the amount of infrared light in a wavelength band that is easily absorbed by a predetermined liquid.

The comparison circuit 62 compares the output signal from the memory 61 and the light receiving element array when the rotating plate 50 rotates 180 degrees from the position shown in FIG. 1 (that is, when the second filter 52 crosses the optical path). 60, and the output signals of each optical fiber constituting the optical fiber array 30 are compared.

The bar separation circuit 63 is a circuit that determines whether or not liquid is leaking from the container rS11 based on the results of individual comparisons in the comparison circuit 62.

The alarm means 64 is a means for warning of liquid leakage through a bell, lamp, etc. when liquid is leaking according to the determination result of the 1-discrimination circuit 63.

Next, the operation of the above embodiment will be explained.

First, it is assumed that the positional relationship between the light source 20 and the optical fiber array 30 is fixed, and the light source 20 and the optical fiber array 30 are moving relative to the welded part 11 of the container 10. It is also assumed that water is leaking from the welded portion 11 as well.

In this case, the light from the light source 20 is reflected by the welding part 11,
The light is sent to the light receiving end face 31 of the optical fiber array 30. This light forms an image on the light receiving element array 60 via the optical fiber array 30 and the imaging lens 41. In this case, the first
As shown in the figure, when the first filter 51 crosses the optical path between the guichroic mirror 42 and the light receiving element array 60, the first filter 51 passes infrared rays in a wavelength band that is easily absorbed by water. At this time, the level of the output signal in the light receiving element array 60 becomes low.

This low level signal is then stored in the memory 61.

On the other hand, after the rotary plate 50 rotates 180 degrees, the light receiving element array 60 receives infrared rays that have passed through the second filter 52 that passes infrared rays in a wavelength band that is difficult to be absorbed by water. The level of the output signal at is not lowered.

Then, the output of the memory 61 is 1, and the second filter 5 is
Since the output signal - when the light receiving element f array 60 receives the light that has passed through the light receiving element f array 60 is different from the output signal -, the output of the comparison circuit 62 becomes larger. Therefore, the determination circuit 63 determines that a liquid leak has occurred.

・Power, melting Jti! ! 'If water is not leaking from B 11, the amount of light that passes through the optical fiber array 30 and is reflected by the microchroic mirror 42 is the same as the amount of light that passes through the first filter 51 and the amount of light that passes through the second filter 52. Since the amounts of light at the time are the same, the levels of the two input signals of the comparing circuit 62 are the same, and the determining circuit 63 determines that no water is leaking.

In the example h, even if the welded part 11 has some unevenness,
If liquid is leaking, the leak can be reliably detected.

In the embodiment L, the memory 61 stores the first filter 5
1 is a gicroic mirror 42 and a light receiving element array 60
When the light receiving element array 6 is crossing the optical path between
The second filter 5 stores an output signal of 0.
2 is a gicroic mirror 42 and a light receiving element array 60
The memory 61 may store the output signal of the light receiving element array 60 while crossing the optical path between the light receiving element array 60 and the light receiving element array 60.

Further, in the above embodiment, a chopping means is used in which the first filter 51 and the second filter 52 are arranged alternately by using the rotary plate 50.
The light that has passed through the optical fiber 50 is divided into two by other means (for example, branching the optical fiber array 30/r stage), and each of the two divided lights is passed through the first filter 51 and the second filter. By allowing the light to pass through two filters and providing two light receiving element arrays corresponding to the light receiving element array 60, rotating parts such as the rotating plate 60 can be omitted.

Furthermore, although water has been described as an example of the liquid leaking from the container 10, leakage of other liquids may also be detected, and the wavelength characteristics of the first filter 51 may be changed depending on the liquid. In the above embodiment, the gicroic mirror 42 was used, but a total reflection mirror may be used instead. In this case, the visible light sensor 70 is not required.

[Effects of the Invention] According to the present invention, there is an effect that liquid leakage from a container can be automatically detected.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the present invention. FIG. 2 is a block diagram showing an example of signal processing in the embodiment described above. FIG. 3 is a perspective view showing the container and its welded portion. 10... Container, 11... Welding part. 20... Light source, 30... Optical fiber array, 42... Guicroic mirror, 50... Rotating plate as a chopping stage. 51...first filter, 52...second filter. 60...Photodetector T array, 61...Memory. 62... Comparison circuit, 63... PaI separate means. Patent applicant: Japan Sensor Association Corporation Figure 2

Claims (4)

[Claims] (1) A light source that illuminates the wall surface of the container; An infrared detection element array; A first filter that passes infrared rays in a wavelength band that is easily absorbed by a predetermined liquid; A first filter that passes infrared rays in a wavelength band that is difficult to be absorbed by the liquid. a second filter; a comparison unit that compares the amount of light that has passed through the first filter and the amount of light that has passed through the second filter; and a determination unit that determines the presence of liquid according to the comparison result. A liquid leakage detection device for a container, characterized in that: (2) A liquid leak detection device for a container according to claim 1, wherein the liquid is water. (3) In claim 1, a visible light detection array is provided, and a dichroic mirror is provided that separates light into infrared light directed toward the infrared detection array and visible light directed toward the visible light sensor. A container liquid leak detection device characterized by: (4) In claim 1, the first filter and the second filter are arranged alternately in an optical path in which reflected light from the light source is reflected by the container toward the infrared detection element array. A liquid leak detection device for a container, comprising a chopping means for disposing.