JPH0616829U - Optical detector - Google Patents

Abstract

(57) [Summary] [Purpose] A device that accurately detects a detection target in the detection space with an optical detector without being affected by airborne dust, vapor, etc. in the detection space. [Structure] Optical detector (1a) in which a light projector (13) and a light receiver (14) are arranged on both sides of a detection space (m) to be detected.
The nozzle (4) of the penetration type air gun (3) is arranged coaxially with the optical axis (2a). The nozzle (4) is arranged between the light projector (13) and the detection space (m) with its air discharge port (8) facing the detection space (m). Compressed air (9) is sent to the nozzle (4) to eject air from the air discharge port (8) to the detection space (m) to form a clean air jet flow path (10) in the detection space (m). By passing the light of the light projector (13) through the air jet flow path (10), the light reaches the light receiver (14) without being attenuated by the suspended dust and vapor in the detection space (m).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an optical detection device that optically detects various situations such as the presence or absence of an object.

[0002]

[Prior art]

 Optical detection devices used for detecting the presence or absence of steel in a steel production line are generally transmission type or reflection type optical detectors equipped with a pair of projector and receiver, and radiation type optical detectors.

FIG. 4 shows the above-mentioned transmission type optical detector, in which a light transmitter (13) and a light receiver (14) are arranged on both sides of a detection space (m 2) to be detected with their optical axes aligned. ing. The light (laser light, infrared light, etc.) emitted from the light emitter (13) passes through the detection space (m) and is received by the light receiver (14). When a detection target such as steel is present in the detection space (m), the light of the projector (13) is blocked by the detection target and does not enter the light receiver (14). Whether or not there is a detection target in the detection space (m) is detected by determining the output level of the light receiver (14).

[0004]

[Problems to be solved by the device]

 The performance of the optical detection device as described above may be affected by the environment in which it is used.

That is, for example, dust or the like may float or steam generated when cooling high-temperature steel flows into the space to be detected in the steel manufacturing line. The light emitted from the projector projected onto the detection target space may be refracted by floating dust particles or vapor in the detection target space, and the amount of light incident on the photodetector may decrease, causing the photodetector to malfunction.

The object of the present invention is to provide a high-performance, high-reliability optical detection that detects a detection target without being affected by dust or steam that is inadvertently suspended in the detection target space. To provide a device.

[0007]

[Means for Solving the Problems]

 The present invention provides an optical detector that optically detects a detection target by directing the optical axis to the detection target and a nozzle having a linear through hole that has an air suction port at one end and an air discharge port at the other end. It is equipped with a through-type air gun that sends compressed air and ejects air from the air outlet in the direction of the center line of the through hole.Make the nozzle of the air gun match the center line of the through hole with the optical axis of the optical detector. By arranging it between the optical detector and the object to be detected, the above object is achieved.

[0008]

[Action]

 The air sprayed from the nozzle of the air gun, which is located between the optical detector and the object to be detected, flows through the space between the optical detector and the object to be inspected, and blows away dust and vapors floating in this space. To form a clean air jet flow path. The optical axis of the optical detector is located in this air jet flow path, and the optical detector always detects the detection target through a clean space.

[0009]

【Example】

 The first to third embodiments shown in FIGS. 1 to 3 will be described below in order.

The optical detection device shown in the first embodiment of FIG. 1 comprises a transmission type optical detector (1a) and a through type air gun (3). The optical detector (1a) has the same structure and function as the optical detector shown in FIG. 4, and has a pair of light emitter (13) and light receiver (14) on both sides of the detection space (m) to be detected. They are placed facing each other.

The penetrating air gun (3) includes a cylindrical nozzle (4) and a pipe (6) for sending a compressed air (9) into the nozzle (4). A linear through hole (5) is formed in the nozzle (4) in the axial direction. The opening at one end of the through hole (5) is the air suction port (7), and the opening at the other end is the air discharge port (8). When compressed air (9) from the pipe (6) is jetted in a spiral shape approximately in the center of the through hole (5), outside air is sucked into the through hole (5) from the air suction port (7). , Which is confused with the compressed air (9) and is ejected as an air jet from the air discharge port (8).

In the embodiment shown in FIG. 1, the nozzle (4) of the air gun (3) is arranged between the light projector (13) and the detection space (m) to be detected with the following position regulation. The center line of the through hole (5) of the nozzle (4) is substantially aligned with the optical axis (2a) of the light emitter (13) and the light receiver (14), and the nozzle (4) is arranged in front of the light emitter (13). . At the same time, the air suction port (7) of the nozzle (4) is directed toward the projector (13), and the air discharge port (8) is directed toward the detection space (m).

When the optical detector (1a) is operated in the state shown in FIG. 1, the light from the light projector (13) passes through the through hole (5) of the nozzle (4) and goes from the detection space (m) to the light receiver (14). And the presence or absence of a detection target in the detection space (m) is detected. In parallel with this optical detection operation, compressed air (9) is supplied to the nozzle (4) of the air gun (3).

Then, an air jet is ejected from the air discharge port (8) of the nozzle (4) toward the detection space (m 2) and the light receiver (14), and between the nozzle (4) and the light receiver (14). An air jet channel (10) is formed. If the air sucked into the air suction port (7) of the nozzle (4) and the compressed air (9) of the pipe (6) are clean air, the air jet flow path (10) will be clean. It becomes a tunnel, and this air jet flow path (10) crosses the detection space (m) to be detected and reaches the light receiver (14). For example, if dust is floating in the detection space (m), the air dust that blows away by the air jet that crosses the detection space (m) cleans the air jet channel (10) in the detection space (m). It will be an air tunnel.

Therefore, the light from the projector (13) always reaches the light receiver (14) through the clean air jet flow path (10) without being affected by the suspended dust and vapor in the detection space (m). Therefore, there is no concern that the light receiver (14) will malfunction.

The operation of the air gun (3) is set only when the amount of suspended dust and vapor in the detection space (m) exceeds a certain reference value that deteriorates the performance of the optical detector (1a). Good too. For example, if compressed air (9) is supplied to the air gun (3) by a light reduction signal to the light receiver (14) and the air gun (3) is operated intermittently, there is no unnecessary movement, and energy saving type Will be the one.

Although not shown, the nozzle (4) of the air gun (3) is provided between the light receiver (14) and the detection space (m), and the air discharge port (8) is provided in the detection space (m). You may arrange it in the direction. In addition, you may arrange | position in both a light projector and a light receiver.

The optical detector of the second embodiment shown in FIG. 2 comprises a reflection type optical detector (1b) and an air gun (3) similar to the above. The reflective optical detector (1b) has a built-in light transmitter and light receiver, projects light to the detection space (m) of the detection target, and receives reflected light from the detection target (11) of the detection space (m). .

In the case of the device shown in FIG. 2, the nozzle (4) of the air gun (3) is coaxially arranged in front of the reflective optical detector (1b), and an air jet is ejected from the nozzle (4) into the detection space (m). The optical axis (2b) of the reflection type optical detector (1b) is positioned in the air jet flow path (10) formed by jetting. By doing so, the light projection path and the reflection light path of the reflection type optical detector (1b) are formed in the clean air jet flow path (10), and are affected by suspended dust and vapor in the detection space (m). Optical detection is performed without any.

The optical detection device of the third embodiment shown in FIG. 3 comprises a radiation type optical detector (1c) and an air gun (3) similar to the above. The radiation type optical detector (1c) receives light (such as infrared rays) from the detection target (12) in the detection space (m) of the detection target.

Also in the case of the apparatus shown in FIG. 3, the nozzle (4) of the air gun (3) is coaxially arranged in front of the radiation type optical detector (c), and the air jet is discharged from the nozzle (4) into the detection space (m). Squirt out. Then, the light from the detection target () passes through the clean air jet flow path (10) and the nozzle (4) and reaches the optical detector (1c), so that the optical detector (1c) detects the detection space (m). Accurate optical detection operation without being affected by airborne dust and vapor.

[0022]

[Effect of device]

 According to the present invention, even if the space between the optical detector and the inspection object is in a non-clean state due to suspended dust and steam, the air jet from the nozzle of the air gun produces a clean air jet. Since the optical detector operates by forming a passage and passing light through this air jet flow path, high-reliability optics that does not deteriorate performance even in a non-clean environment where dust and debris floats or in a harsh environment where steam flows in A detection device can be provided.

[Brief description of drawings]

FIG. 1 is a side view of a main part including a partial cross section of an optical detection device according to a first embodiment of the present invention.

FIG. 2 is a side view of a main part including a partial cross section of an optical detection device according to a second embodiment of the present invention.

FIG. 3 is a side view of a main part including a partial cross section of an optical detection device according to a third embodiment of the present invention.

FIG. 4 is a side view of a main part of a conventional optical detection device.

[Explanation of symbols]

 1a Optical detector 1b Optical detector 1c Optical detector 2a Optical axis 2b Optical axis 3 Air gun 4 Nozzle 5 Through hole 7 Air suction port 8 Air discharge port 9 Compressed air 10 Air jet flow path

Continued Front Page (72) Inventor Satoru Miyashita 2-1-1 Sonezaki, Kita-ku, Osaka City, Osaka Prefecture Hokuyo Electric Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. An optical detector for optically detecting a detection target by directing an optical axis to the detection target, and a nozzle having a linear through hole having an air suction port at one end and an air discharge port at the other end. A through-type air gun that sends compressed air to the center of the through hole from the air discharge port, and the center line of the through hole is the optical axis of the optical detector. The optical detection device is arranged between the optical detector and the detection target so that the optical axis of the optical detector is located in the air jet passage of the air jetted from the air gun.