JPH04198703A - Optical fiber sensor - Google Patents

Abstract

PURPOSE:To blow away floating dust and scattering water drops in the vicinity of a detection face of a sesor head by generating an air current which fast flows to the outside from the inside of a housing body in the vicinity of the detection face. CONSTITUTION:Compressed air is fed to a space, which is formed in a sensor head housing body 10, by connecting to a joint 18 a house whose on end is connected to a compressor. This compressed air is converged in front of a detection face 3a of a sensor head 3 and its stream is gathered up by a tapered face and discharged outside from a discharge outlet 13. The vicinity of the detection face of the sensor head 3 thus generates an air current, which flows fast to the outside from the inside of the housing body 10 and blows away floating dust and scattering water drops in the vicinity of the detection face 3a of the sensor head 3 to prevent them from sticking to the detection face 3a.

Description

Detailed Description of the Invention [Objective of the Invention] [Industrial Application Field] The present invention is an optical fiber sensor that detects an object by projecting light onto the object or receiving reflected light from the object using an optical fiber. Regarding.

[Conventional technology]

In the conventional optical fiber sensor, as shown in FIG. 3, the base end of an optical fiber 2 is connected to a controller 1, and a sensor head 3 is provided at the tip of the optical fiber 2.

Note that the reference numeral 4 is a cable that connects the controller 1 to a power source and an external device. The sensor head 3 is a metal tube in which the vicinity of the tip of an optical fiber is inserted into a metal tube, and the metal tube is filled with a resin or the like to harden it.The end surface 3a of the sensor head, which serves as a detection surface, is polished to prevent light from traveling straight. Improving sexuality.

In such an optical fiber sensor, a sensor head 3 is fixedly arranged near an object to be detected, and light transmitted from a controller 1 via an optical fiber 2 is projected from a detection surface 3a onto the object to be detected. Then, the reflected light from the object to be detected is received by the detection surface 3a of the sensor head 3, and the optical fiber 2
The presence of the object to be detected is determined based on the amount of reflected light.

However, the above-mentioned optical fiber sensor may be used in places with a lot of dust or water droplets, and when used in such environments, dust may adhere to the detection surface 3a of the sensor head 3. There is an extremely high possibility that water droplets will adhere to the sensor, and in such cases, detection accuracy will drop significantly.

[Problem to be solved by the invention]

Therefore, depending on the environment in which conventional optical fiber sensors are used, there is a possibility that dust or water droplets may adhere to the detection surface, resulting in a significant decrease in detection accuracy.

The present invention has been made in view of the above-mentioned circumstances, and provides an optical fiber sensor that can reliably prevent dust or water droplets from adhering to the detection surface of a sensor head, and can always maintain high detection accuracy. The purpose is to

[Structure of the Invention] [Means for Solving the Problem] In order to achieve the above object, an optical fiber sensor according to the present invention projects light onto an object from a sensor head formed at the tip of an optical fiber, and/or In an optical fiber sensor that detects information about the object by receiving reflected light from an object with the sensor head, the sensor head is housed to form a space between the sensor head and the sensor head, and a compressor is supplied from the outside. A sensor head housing is provided with a supply port for allowing air to flow into the space, and a discharge port for discharging the compressed air from the end surface of the sensor head to the outside on a surface facing the end surface of the sensor head. It has been decided that this will be established.

[Effect]

By taking the above measures, the present invention supplies compressed air supplied from the outside from the supply port of the sensor head housing into the space formed between the sensor head and the sensor head housing, Compressed air is vigorously released from the outlet formed on the surface facing the end surface of the sensor head, and dust and water droplets existing near the end surface of the sensor head are blown away to the outside. adhesion is prevented.

〔Example〕

Examples of the present invention will be described below.

FIG. 1 is a diagram showing an embodiment of the present invention, and shows a cross-sectional structure of a sensor head housing which is a main part of the embodiment. In this embodiment, the sensor head 3 is inserted through an opening at one end of a holder 11 having a cross-sectional shape shown in FIG. 2, and a block 12 is screwed into the opening at one end of the holder 11.

A sensor head storage body 10 is constituted by the holder 11 and the block 12.

The holder 11 has a discharge port 13 formed on a surface facing the end surface of the sensor head, which serves as a detection surface. This discharge port 13 is formed with a tapered surface that converges from the inside of the holder 11 to the outside. Further, semicircular grooves 14a to 14d are formed in the inner wall of the holder 11 in the longitudinal direction, and a space 15 connected to the discharge port 13 is formed between the plurality of grooves and the outer circumferential surface of the sensor head. The outer circumferential surface of the sensor head 3 is held by the convex shape formed by the adjacent grooves.

Further, the block 12 is penetrated by the optical fiber 2, and an O-ring 16 is fitted between the block 12 and the tip fiber 2 to isolate it from the outside. Furthermore, a hole 17 is formed in the block 12 to communicate the space inside the block with the outside. A joint 1 is inserted into this hole 17 from the outside of the block 12.
8 is installed. This joint 18 is connected to a compressor (not shown) via a hose.

The base end of the optical fiber 2 is connected to the controller 1 as shown in FIG.
Connected to power supply and external equipment via. Note that the controller 1 has basic functions as an optical sensor, such as inputting measurement light into the optical fiber 2 and detecting information regarding the object to be detected from the light received by the sensor head 3.

Next, the operation of this embodiment configured as above will be explained.

A hose whose one end is connected to a compressor is connected to the joint 18 to send compressed air into the space formed between the outer periphery of the sensor head 3 and the sensor head housing 10. The compressed air sent through the hole 17 is directed to the sensor head 3 along the arrow.
The detection surface 3a of the sensor head 3 passes through the grooves 14a to 14d of the holder 11 that accommodates the
focused in front. The flow path of the focused compressed air is constricted by the tapered surface and is discharged to the outside from the discharge port 13, so a fast-flowing air current flows from inside the storage body 10 to the outside near the detection surface of the sensor head 3. As a result, dust and water droplets floating near the detection surface 3a of the sensor head 3 are blown away to the outside, and are prevented from adhering to the detection surface 3a.

Therefore, according to this embodiment, compressed air is flowed from the outer periphery of the sensor head 3 to blow off dust and water droplets near the detection surface to the outside from the discharge port 13, so that it can be used in an environment where dust and water droplets fly. However, it is possible to reliably prevent them from adhering to the detection surface 3a of the sensor head 3, and maintain high detection accuracy. In addition, dust etc. may be removed from the detection surface 3a.
This has the advantage that maintenance of the sensor head 3 becomes unnecessary because it can prevent the particles from adhering to the sensor head 3.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to reliably prevent dust or water droplets from adhering to the detection surface of the sensor head.
It is possible to provide an optical fiber sensor that can always maintain high detection accuracy and improve reliability as a sensor.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a sensor head storage body used in an embodiment of the present invention, Fig. 2 is a sectional view of a holder used in the same embodiment, and Fig. 3 is the overall configuration of an optical fiber sensor. FIG. 2... Optical fiber, 3... Sensor head, 10.
...Sensor head storage body, 11...Holder, 12.
...Block, 13...Discharge port, 14...Groove, 16
...O-ring, 17...hole, 18...fitting. Applicant's agent Patent attorney Takehiko Suzue ML Figure 2 Figure 3

Claims (1)

[Claims] An optical fiber sensor that detects information about an object by projecting light onto an object from a sensor head formed at the tip of an optical fiber and/or receiving reflected light from the object with the sensor head. A supply port is formed to accommodate the sensor head and form a space between the sensor head and the sensor head, and to allow compressed air supplied from the outside to flow into the space. An optical fiber sensor comprising: a sensor head housing having a discharge port for discharging the compressed air from an end surface of the sensor head to the outside.