JP2009139290A - Pin hole detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pin hole detector capable of properly preventing intrusion of light leaking from a plate material width end into a light reception part with a simple structure, and accurately detecting a pin hole, as a pin hole detector for detecting a pin hole occurring on an opaque plate material such as a steel plate. <P>SOLUTION: An edge mask 14 includes a cutout part 21 positioning a width end of a steel plate 16 to surround it by a predetermined length δ in the width direction; the cross-sectional shape of the cutout part 21 is a parallelogram having an opening 21k as one side; the upper inner surface 21a and the lower inner surface 21b of the cutout part 21 are each used as a light reflecting surface; and a part 14a located behind the cutout part 21 is formed of a member high in optical transparency. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pinhole detector that detects a pinhole of an opaque plate material such as a steel plate, and more particularly to a pinhole detector that can detect a pinhole up to an end in the width direction of a plate to be detected.

  Cold rolled steel sheets, such as stainless steel sheets and plated steel sheets, have severe restrictions on the existence of pinholes for applications, so pinholes are detected, quality guaranteed, and shipped.

  The pinhole detector used at that time is usually disposed above the traveling strip-shaped steel plate (test plate material), and is disposed below the steel plate, a light source unit that emits light over the entire width of the steel plate, The light receiving part that detects the irradiation light from the light source part that has passed through the pinhole, and arranged so as to face both ends in the width direction of the steel plate, move in the width direction according to the width of the steel plate, It consists of a pair of edge masks for preventing leaked light from entering the light receiving part.

  FIG. 4 shows an example of a conventionally used pinhole detector. In this pinhole detector 60, the irradiation light 67 emitted from the light source unit 61 passes through the pinhole 70 of the steel plate 66 and is captured by the optical fiber 62 a of the light receiving unit 62 below the steel plate 66, and is a photomultiplier tube. Amplified at 62b. The received light signal is compared with the reference signal and output as a pinhole detection signal. At this time, when the irradiation light 67 hits the plate width end portion, the irradiation light 67 is refracted at the steel plate width end portion by the diffraction action, and enters the light receiving portion 62 as leakage light. Therefore, there is a possibility that the light reception signal of the leaked light is overdetected as the presence of a pinhole. Further, if this light leakage signal is removed by filtering, the light reception signal of the true pinhole is also removed, and there is a possibility that the true pinhole cannot be detected. In particular, detection is impossible in the case of a minute pinhole. Therefore, in order to prevent this, in this pinhole detector 60, a U-shaped edge mask 64 is provided at both width end portions of the steel plate 66 (in FIG. 4, only one width end portion is shown), and the edge The position of the edge mask 64 is moved and adjusted in accordance with the width of the steel plate 66 so that the mask 64 and the steel plate width end overlap each other by about 50 mm. In addition, 65 in FIG. 4 is a shutter.

  However, in the above-described pinhole detector 60, the edge mask 64 overlaps with the steel plate width end portion by about 50 mm. Therefore, the pinhole 70e at the steel plate width end portion cannot be detected. Moreover, in order to guarantee quality, truncating the width end of the steel sheet causes a decrease in yield.

In order to solve this problem, in Patent Document 1, as shown in FIGS. 5A and 5B, the pinhole detector 80 includes an edge mask 85 to which a porous member 88 having a light-absorbing color is attached. As a result, the leaked light 95 irradiated from the light source unit 81 and reflected by the surface of the steel plate 84 is attenuated by the porous member 88, so that the leaked light 95 goes around the steel plate width end and enters the light receiving unit 82. As shown in FIG. 5 (c), in order to detect the pinhole 90 at the steel plate width end, a window 91 is provided in the edge mask 85 as a light path dedicated to the steel plate width end. Yes.
Japanese Utility Model Publication No. 6-51863

  However, in the pinhole detector described in Patent Document 1, it is difficult to prevent light that has passed through the window provided in the edge mask from being diffracted at the width end of the steel plate and entering the light receiving unit. In addition, the edge mask is structurally complicated, and equipment costs are increased.

  The present invention has been made in view of the above circumstances, and as a pinhole detector for detecting a pinhole generated in an opaque plate material such as a steel plate, light leaked from the end of the plate width is received. An object of the present invention is to provide a pinhole detector capable of accurately detecting pinholes with a simple structure and accurately preventing entry into a portion.

  In order to solve the above problems, the present invention has the following features.

[1] A light source unit that is disposed on one surface side of the traveling test plate material, irradiates light over the entire width of the test plate material, and is disposed to face the light source unit across the test plate material. The light receiving unit that detects the irradiation light from the light source unit that has passed through the pinhole and the width of the test plate material are arranged so as to be movable in the width direction. In the pinhole detector provided with an edge mask for preventing the light from entering the light-receiving part around the part,
The edge mask includes a notch portion that opens to the test plate material side and is positioned so as to surround the width end portion of the test plate material by a predetermined length in the width direction, and the notch portion travels the test plate material. The shape seen in the direction is a parallelogram with the opening as one side, and the inner surface on the light source side and the inner surface on the light receiving side are each a light reflecting surface and located behind the notch. The pinhole detector is characterized in that the portion to be formed is formed of a member having high light transmittance.

  [2] The inner surface on the light source unit side and the inner surface on the light receiving unit side of the test plate material are light reflecting surfaces by applying a reflective agent, as described in [1] above Pinhole detector.

  [3] The pinhole detector according to [1] or [2], wherein the portion located behind the notch is formed of glass.

  [4] The parallelogram, which is the cross-sectional shape of the notch, is inclined such that the inner surface on the light source unit side and the inner surface on the light receiving unit side move away from the light source unit as they move away from the opening. The pinhole detector according to any one of [1] to [3], wherein the angle is 30 ° to 40 °.

  [5] The pinhole detector according to any one of [1] to [4], wherein the width direction length of the width of the test plate material surrounded by the notch is 1 mm to 3 mm.

  [6] A guide roll fixed to the edge mask is provided, and by pressing the guide roll against the width end portion of the test plate material, the width direction length of the test plate material width end portion surrounded by the notch portion is a predetermined value. The pinhole detector according to any one of [1] to [5] above, wherein

  In the present invention, it is possible to accurately prevent the leaked light from the edge portion of the test plate material from entering the light receiving portion with a simple structure and to detect the pinhole with high accuracy.

  An embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall schematic diagram of a pinhole detector according to an embodiment of the present invention, FIG. 2 is an enlarged view of a main part thereof, and FIG. 3 is a partial plan view thereof.

  As shown in FIG. 1, the pinhole detector 10 according to this embodiment is disposed on the upper surface side of a steel plate (test plate material) 16 that runs in a horizontal direction perpendicular to the paper surface, and light 17 over the entire width of the steel plate 16. And a light receiving portion 12 (optical fiber 12a and photomultiplier tube) that is disposed on the lower surface side of the steel plate 16 so as to face the light source portion 11 and detects the irradiation light 17a that has passed through the pinhole 20 of the steel plate 16. b) and at both width end portions of the steel plate 16 movably arranged in the width direction (in FIG. 1, only one width end portion is shown), and the irradiation light 17 from the light source unit 11 is the width end portion of the steel plate 16. Are provided with an edge mask 14 and a shutter 15 for preventing the light from entering the light receiving unit 12.

  In addition, in this embodiment, the edge mask 14 is a member having a rectangular cross section, and is opened to the steel plate 16 side at the height position of the pass line on which the steel plate 16 travels as shown in FIG. A cutout portion 21 is provided for positioning the 16 width end portions so as to surround a predetermined length δ (for example, δ = 1 to 3 mm) in the width direction. The notch 21 penetrates in the traveling direction of the steel plate 16, has a hollow inside, and has a parallelogram shape when viewed in the traveling direction of the steel plate. The parallelogram is formed by four sides of the opening 21k, the inner surface (upper inner surface) 21a on the light source unit 11 side, the inner surface (lower inner surface) 21b on the light receiving unit 12 side, and the inner surface 21c. The upper inner surface 21a and the lower inner surface 21b are inclined downward at a predetermined inclination angle θ (for example, θ = 30 ° to 40 °).

  A portion (notch portion forming member) 14p positioned above and below the notch 21 including the front surface 14a of the edge mask 14 is formed of a light-impermeable material, while the rear surface of the edge mask 14 is provided. 14b and the part (notch part back member) 14s located behind the notch part 21 including the back inner surface 21c of the notch part 21 are formed of a member (for example, glass) with high light transmittance. . Further, the upper inner surface 21a and the lower inner surface 21b are coated with a reflective agent so that light is reflected.

  Further, as shown in the plan view of FIG. 3, the guide rolls 26 attached to both ends of the connecting rod 25 mechanically connected to the edge mask 14 are pressed against the width end of the steel plate 16 with a predetermined pressure. Thus, even if there is a width variation or meandering of the steel plate 16, the length δ surrounded by the notch 21 is always maintained at a predetermined value.

  The opening amount of the opening 21k is several times the thickness of the steel plate 16 in consideration of the thickness of the steel plate 16 and slight sagging, and is about 5 to 10 mm.

  In the pinhole detector 10 configured as described above, the irradiation light 17 a that has passed through the pinhole 20 of the steel plate 16 out of the irradiation light 17 emitted from the light source unit 11 is captured by the optical fiber 12 a of the light receiving unit 12. And amplified by the photomultiplier tube 12b. The received light signal is compared with the reference signal and output as a pinhole detection signal.

  On the other hand, in the irradiation light 17 emitted from the light source unit 11, the light 17b diffracted by the opening 21k of the notch 21 is reflected by the lower inner surface 21b of the notch 21 and is cut from the inner surface 21c. It passes through the notch rear member 14s and exits from the rear surface 14b.

  In addition, in the irradiation light 17 emitted from the light source unit 11, the light 21c reflected upward at the width end of the steel plate 16 is reflected by the upper inner surface 21a of the notch 21, and from the inner surface 21c. It passes through the notch rear member 14s and exits from the rear surface 14b. Alternatively, the light is reflected by the lower inner surface 21b, passes through the notch rear member 14s from the inner surface 21c, and exits from the rear surface 14b.

  Incidentally, since the pinhole detector 10 is installed in a place with a good atmosphere, dust such as dust that prevents reflection of light or the like does not accumulate in the notch 21.

  In this way, in this embodiment, it is possible to accurately prevent the irradiation light 17 emitted from the light source unit 11 from entering the light receiving unit 12 by going around the width end of the steel plate 16. Accordingly, pinholes in the vicinity of the width end of the steel plate 16 can be detected with high accuracy. As a result, it is possible to solve the problem of quality assurance due to the detection failure of the pinhole and the problem of yield reduction due to the cutting off of the width end of the steel plate.

  In this embodiment, the steel plate travels in the horizontal direction, but the present invention is not limited to this, and can be applied even when the steel plate travels in another direction (for example, the vertical direction). it can.

1 is an overall schematic diagram of an embodiment of the present invention. It is a principal part enlarged view of one Embodiment of this invention. It is a fragmentary top view of one embodiment of the present invention. It is a whole schematic diagram of a prior art. It is explanatory drawing of a prior art (patent document 1).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pinhole detector 11 Light source part 12 Light receiving part 12a Optical fiber 12b Photomultiplier tube 14 Edge mask 14a Front surface of edge mask 14b Rear surface of edge mask 14p Notch part formation member 14s Notch part rear member 15 Shutter 16 Steel plate 17 Irradiated light 17a Irradiated light that has passed through the pinhole 17b Diffracted light at the notch 17c Reflected light at the end of the plate width 20 Pinhole 21 Notch 21k Notch opening 21a Notch upper upper surface 21b Lower inner surface of notch 21c Inner inner surface of notch 25 Connecting rod 26 Guide roller 60 Pinhole detector 61 Light source 62 Light receiver 62a Optical fiber 62b Photomultiplier tube 64 Edge mask 65 Shutter 66 Steel plate 67 Direct light 70 Pinhole 80 Pinhole inspection Vessel 81 light source unit 82 receiving unit 84 steel 85 edge mask 88 porous member 90 pinhole 91 window portion 95 leaks light

Claims (6)

It is arranged on one surface side of the traveling test plate material, and it is arranged to face the light source unit with the test plate material sandwiched between the light source unit that irradiates light over the entire width of the test plate material, and the pinhole of the test plate material A light-receiving unit that detects the light emitted from the light source unit that has passed through, and a width-movable part at both width ends of the test plate material, and the light emitted from the light source unit travels around the width end of the test plate material In the pinhole detector with an edge mask for preventing the light from entering the light receiving part,
The edge mask includes a notch portion that opens to the test plate material side and is positioned so as to surround the width end portion of the test plate material by a predetermined length in the width direction, and the notch portion travels the test plate material. The shape seen in the direction is a parallelogram with the opening as one side, and the inner surface on the light source side and the inner surface on the light receiving side are each a light reflecting surface and located behind the notch. The pinhole detector is characterized in that the portion to be formed is formed of a member having high light transmittance.   2. The pinhole detector according to claim 1, wherein an inner surface on the light source unit side and an inner surface on the light receiving unit side of the test plate material are light reflecting surfaces by applying a reflective agent. .   The pinhole detector according to claim 1 or 2, wherein a portion located behind the notch is made of glass.   The parallelogram, which is the cross-sectional shape of the notch, is inclined so that the inner surface on the light source unit side and the inner surface on the light receiving unit side move away from the light source unit as the distance from the opening increases. The pinhole detector according to claim 1, wherein the pinhole detector has an angle of ˜40 °.   The pinhole detector according to any one of claims 1 to 4, wherein a width direction length of the test plate material width end portion surrounded by the notch portion is 1 mm to 3 mm.   A guide roll fixed to the edge mask is provided, and by pressing the guide roll against the width end portion of the test plate material, the width direction length of the test plate material width end portion surrounded by the notch portion is maintained at a predetermined value. The pinhole detector according to claim 1, wherein the pinhole detector is configured as described above.

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