JPH0712959U - Electrical noise eliminator for steel sheet surface defect inspection equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an electrical noise removing device for a steel strip surface defect inspection device. An electrical noise removing device for inspecting a surface defect of a steel strip 1 conveyed through a continuous processing line by using a surface defect inspection device 10, wherein the surface is oriented in the traveling direction of the steel strip 1. Disposing the iron rolls 11 and 12 which are grounded on the upstream side and the downstream side across the defect inspection device 10 to ground the steel strip 1 and to release the electrical noise caused by the steel strip 1 to the ground. Thereby, the detection performance of the surface defect inspection apparatus 10 can be sufficiently enhanced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an electrical noise eliminator for a steel strip surface defect inspection apparatus.

[0002]

[Prior art]

 Normally, a surface defect inspection device (hereinafter simply referred to as an inspection device) is used to inspect the surface quality of a steel strip that is a product or a semi-finished product in a refinement line that continuously processes steel strips. The equipment is generally installed at a position close to the final stage just before winding the steel strip on the target line (for example, Tanaka et al., "Practical use of automatic surface flaw inspection device in continuous annealing line"). (See The Iron and Steel Institute of Japan, "Materials and Processes", CAMP-ISIJ Vol.6 (1993) -336).

As such an inspection device, a device using an optical means such as a laser beam is often adopted, and in that case, a light-shielding process is performed to prevent malfunction due to ambient light. There are many cases. Further, since the inspection apparatus itself handles extremely weak signals, it is also sensitive to electrical noise, and various measures have been taken against electrical noise (for example, Japanese Patent Laid-Open No. 53-116889). (See Japanese Laid-Open Patent Publication No. 58-75050). The main sources of this electrical noise are spark discharges of static electricity caused by friction when a sheet-shaped steel strip is conveyed by a conveyor that is an insulator.

[0004]

[Problems to be solved by the device]

 However, there is a limit to the countermeasures that can be adopted by the inspection equipment when electrical noise sources such as those mentioned above come from the steel strip itself and random noise occurs. However, the reality is that the usage of the inspection device must be restricted, such as reducing the sensitivity of use. Therefore, the original performance of the inspection equipment cannot be exhibited 100%, and the inspection equipment must be used with its performance lowered, which makes it impossible to make full use of the originally intended defect detection capability. It was

The present invention has been made in order to solve the above-mentioned problems of the conventional technology, and suppresses the electrical noise caused by the steel strip itself by improving the installation conditions of the inspection device. It is an object of the present invention to provide an electrical noise eliminator for a steel strip surface defect inspection device.

[0006]

[Means for Solving the Problems]

 The present invention is an electrical noise eliminator for inspecting a surface defect of a steel strip conveyed through a continuous processing line using a surface defect inspection device, wherein the surface defect inspection is performed in the traveling direction of the steel strip. An electrical noise eliminator for a surface defect inspection device for a steel strip, characterized in that a jig for grounding the steel strip is provided on the upstream side and the downstream side of the device. As the grounding jig, it is preferable to ground an iron roll.

[0007]

[Work]

 According to the present invention, the iron rolls are arranged on the upstream side and the downstream side of the surface defect inspection apparatus and are grounded respectively, so that static electricity or the like, which is a source of electrical noise caused by the steel strip, is released to the ground. be able to. In other words, by grounding the iron roll arranged on the upstream side of the surface defect inspection device, the electrical noise transmitted through the steel strip from various equipment installed on the upstream side and the steel strip itself will be affected. It can play a role of letting energy such as static electricity, which is a source of electrical noise such as accumulated discharge, escape to the ground, while the iron roll arranged downstream of the surface defect inspection device is grounded to the downstream side. It can play the role of escaping the electrical noise that is transmitted through the steel strip and is affected by various equipment installed in the ground.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of an embodiment of the present invention, showing an example of application to a skin pass mill line. In the figure, a steel strip 1 tempered by a skin pass mill 2 is first sheared by a side trimmer 4 after passing through a first bridle roll 3, then a second bridle roll 5, a third bridle roll 6 , The shear 7, the deflector roll 8 and the tension reel 9, and the inspection device 10 is installed between the second bridle roll 5 and the third bridle roll 6, and the upstream side and the downstream side thereof. An input side iron roll 11 and an output side iron roll 12 which are grounded to each other are arranged in contact with the surface of the steel strip 1.

As shown in FIGS. 2 (a) and 2 (b), a brush 13 is brought into contact with the roll surface, and the brush 13 is connected to the wiring 14 by connecting the brush 13 to the wiring 14 It should be grounded via. 3 (a) is shows the original waveform and differential waveform of the defect detection signal when the both grounded entry side steel roll 11 and the exit-side iron roll 12, S ₁ is larger defect signal in a differential waveform, S ₂ is a small defect signal and N is a noise signal. For comparison, Fig. 3 (b) shows the case where only the iron roll 11 on the input side is grounded, and Fig. 3 (c) shows the case where both are not grounded.

It can be seen that the output values of the defect signals S ₁ and S ₂ are at the same level in both cases, whereas the output value of the noise signal N changes greatly. In particular, when the noise signal N is not used, the level of the noise signal N is almost equal to the level of the small defect signal S ₂ , and it is difficult to separate only the defect signal S, but in the case of the present invention, the noise signal N is Since it is the lowest level compared to other cases, it is easy to separate the small defect signal S ₂ and 100% of the performance of the inspection device can be exhibited.

Here, as shown in FIG. 4, when the bridle rolls 11 ′ and 12 ′ are iron rolls, it is not necessary to separately prepare an iron roll, and the bridle rolls 11 ′ and 12 ′ are grounded. You can do it like this. In the above embodiment, the brush 13 is used for grounding the entrance side iron roll 11 and the exit side iron roll 12, but the present invention is not limited to this. For example, a metallic blade (doctor blade) ( Similar effects can be obtained by pressing the blades against the iron rolls 11 and 12 to contact them, or by filling the roll bearings with conductive grease.

[0012]

[Effect of device]

 According to the present invention, the steel strip is grounded on the upstream side and the downstream side of the surface defect inspection apparatus, so that the influence of electrical noise on the surface defect inspection apparatus can be suppressed, and thus the surface defect can be suppressed. Since the detection performance of the inspection device can be sufficiently enhanced, it greatly contributes to product quality assurance.

[Brief description of drawings]

FIG. 1 is a side view of an embodiment of the present invention.

FIG. 2A is a plan view showing an iron roll, and FIG.

3 (a), (b) and (c) are characteristic diagrams showing the output value of a defect signal.

FIG. 4 is a side view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Steel strip 10 Inspection device (Surface defect inspection device) 11 Inlet iron roll 12 Outlet iron roll 13 Brush (Grounding jig)

Claims (2)

[Scope of utility model registration request] 1. An electrical noise eliminator for inspecting a surface defect of a steel strip conveyed in a continuous processing line by using a surface defect inspection device, wherein the surface defect is in the traveling direction of the steel strip. An electrical noise eliminator for a surface defect inspection device for a steel strip, characterized in that a jig for grounding the steel strip is provided upstream and downstream of the inspection device. 2. The electrical noise eliminator for a steel strip surface defect inspection apparatus according to claim 1, wherein the grounding jig is a grounded iron roll.