JP2019074491A - Detector and hood - Google Patents

Abstract

To provide a detector and a hood with which it is possible to suppress an effect on detection results attributable to an obstructing substance while reducing costs under an environment where the obstructing substance that affects light exists.SOLUTION: An oil film detector 1 includes a hood 3 for enclosing the optical path of a laser beam and provided at an underside of oil film detector bodies 2A, 2B. The hood 3 includes a partition 32 located in an internal space A, and an aspirator 33 for supplying air to the internal space A. The aspirator 33 forms a pressure reduced state utilizing the air supplied from a support port 33a and thereby takes in outside air from an intake port 33b, guiding the outside air together with the air from an introduction port 33c into the internal space A. Even when an amount of air supplied from the supply port 33a is small, it is possible to guide a large flow of air into the internal space A and reduce an amount of air consumed. It is possible to reduce vapor existing between the oil film detector bodies 2A, 2B and a liquid surface W by a smaller amount of air than that of conventional one.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a detector used for an oil film detector or the like and a hood used for the detector, for example, which detects an oil film by reflecting detection light on the water surface of a water purification plant, a river, or a lake.

  Focusing on the fact that the reflectance of light by the oil film is higher than the reflectance of light by the water surface, the light is irradiated to the water surface and the reflectance is measured by measuring the intensity of the reflected light, thereby detecting the water surface condition There is a detection method to

The reflectance is determined by measuring the intensity of the reflected light of the light irradiated to the water surface, and when detecting the presence or absence of the oil film on the water surface, it corresponds to the situation that dew condensation occurs in the device and the accuracy of oil film detection decreases. Various configurations have been proposed conventionally.
For example, Patent Document 1 includes a detection unit that receives radiant energy from a measurement target in a heating atmosphere, a purification unit that purifies air in the measurement atmosphere, and a purification unit provided in the measurement target direction of the detection unit. An arrangement is disclosed comprising an air purge pipe for injecting hot air from the air.

Japanese Examined Patent Publication No. 3-37135

  Here, when there is an obstacle that affects the light in the space through which light passes between the detector and the detection surface, air having a predetermined pressure reduces the obstacle in the space and results from the obstacle. In the case of suppressing the influence, it is assumed that the cost increases if a large amount of air supply is required.

  The present invention has been made to solve the technical problems as described above, and the object of the present invention is to reduce the cost while reducing the cost in the environment where the obstacle substance affecting light is present. An object of the present invention is to provide a detector and a hood capable of suppressing the influence of a detection result caused.

To this end, a detector to which the present invention is applied includes: an output means for outputting detection light; a light receiving means for receiving light reflected by the detection surface of the detection light of the output means; Acquiring means for acquiring information on the detected surface based on information of the reflected light received by the means, an enclosing member extending in the optical path direction of the reflected light and surrounding the optical path of the reflected light, and An air supply means for supplying air to the inside, wherein the air is supplied toward the direction of the detection surface inside the enclosure member, and the air outside the enclosure member is generated by the pressure action associated with the air supply. And supply means for supplying air together with air to the inside of the surrounding member.
Here, the enclosure member is configured such that the air and the air supplied to the inside of the enclosure member by the supply means are directed in the direction opposite to the detection surface and then in the direction of the detection surface. It can be characterized by having a partition member which divides an inner space of a member.
Further, a hood to which the present invention is applied is a hood used together with a detector for detecting information related to the detected surface based on information of reflected light from the detected surface, wherein the hood is the reflected light When the air is supplied to the inside of the hood so that the air is directed to the direction of the detection surface inside the hood, the hood is operated by the pressure action associated with the supply. It is characterized in that it is possible to supply the air outside with the air together with the air.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to suppress the influence of the detection result resulting from a disordering substance, reducing cost in the environment where the disordering substance which affects light exists.

It is a block diagram showing an example of composition of an oil film detector main part of an oil film detector. It is a block diagram showing an example of composition of another oil film detector main part of an oil film detector. It is a schematic diagram explaining an oil film detector concerning a 1st embodiment. It is the schematic explaining the oil film detector which concerns on 2nd Embodiment. It is a figure explaining experiment which confirms the effect by this Embodiment, (a) is a figure explaining an experiment apparatus, (b) is a table | surface which shows an experimental result.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.
In the present embodiment, an oil film detector 1 having a function of detecting an oil film by reflecting detection light on a detection target surface (detection target surface) will be described. This function utilizes the property that the reflectance of light when the oil film is present on the liquid surface as the detected surface is different from the reflectance of light when the oil film is not present. The liquid level refers to, for example, the level of a water purification plant, a river, a lake or the like, and the position of the liquid level is high or low, and the liquid level is wavy.
The oil film detector 1 is classified into a fixed type that is used by being placed on a structure near a detected surface that detects the presence or absence of an oil film, and a movable type that moves relative to the detected surface.

[Oil Film Detector Main Body 2A, 2B of Oil Film Detector 1]
The configuration of the oil film detector 1 according to the present embodiment will be described. First, an oil film detector main body 2A and an oil film detector main body 2B will be described as the oil film detector 1 main body. The oil film detector main body 2A will be described with reference to FIG. 1, and the oil film detector main body 2B will be described with reference to FIG. In addition, the oil film detector main body 2A and the oil film detector main body 2B adopt a laser scanning type to reduce the influence of the liquid level change.
FIG. 1 is a block diagram showing a configuration example of an oil film detector main body 2A of the oil film detector 1.
The oil film detector main body 2A of the oil film detector 1 has a laser light source 100 as an example of an output unit that emits a laser light L1 as detection light, and a laser light L1 emitted by the laser light source 100 in parallel with an irradiation range. And a radiation unit 200 for outputting light. To explain further, the irradiation unit 200 outputs the laser light L2 irradiating the irradiation range by scanning the laser light L1. The laser beam L2 has a difference in size between the irradiation range (crossing area of the beam group) on the upstream side of the light path of the laser light L2 and the irradiation range (crossing area of the beam group) on the downstream side of the light path It is parallel light.
The term "parallel light" as used herein refers to a laser beam in which the irradiation area (crossing area) of the light formed in the beam group by scanning one laser beam does not substantially change depending on the position on the optical path. I assume.

Further, the oil film detector main body 2A is a laser beam so that the optical axis of the laser beam L3 irradiated to the liquid surface W as an example of the detected surface and the optical axis of the laser beam L4 reflected by the liquid surface W become coaxial. A coaxial incident unit 300 for guiding L3 and L4 and a light receiving unit 400 as an example of a light receiving unit for receiving the laser beam L5 from the coaxial incident unit 300 are provided. The coaxial incident portion 300 has a half mirror 310 that reflects part of the incident light and transmits the remaining part. The half mirror 310 is a plate-like member formed so that the intensities of the reflected light and the transmitted light are substantially equal.
To explain further, the coaxial light emitting unit 300 reflects the laser light L2 from the irradiating unit 200 to the half mirror 310, guides the laser light L3 which is the reflected light to the liquid surface W so as to be totally reflected, and The laser beam L4 totally reflected by W is transmitted to the half mirror 310, and the transmitted laser beam L5 is guided to be received by the light receiving unit 400. The laser beam L4 is reflected from the liquid surface W at an angle equal to the incident angle of the laser beam L3. That is, the incident angle of the laser beam L3 and the reflection angle of the laser beam L4 are equal to each other.
The emission of the laser beam L3 and the incidence of the laser beam L4 are performed through the window portion 800 which is a transparent member. The window portion 800 is made of, for example, glass.

As described above, the irradiation unit 200 is configured to output the detection light used to detect the oil film on the liquid level W as parallel light that irradiates a predetermined range. The coaxial light incidence unit 300 is configured to cause the detection light to be totally reflected to the liquid surface W by the half mirror 310, and to make the reflected light (detection light) totally reflected toward the light reception unit 400 by the half mirror 310. .
For this reason, it is possible to irradiate detection light in a wide range, and even if the height of the liquid surface W fluctuates and the distance to the oil film detector main body 2A changes, the detection light necessary for oil film detection by the light receiver 400 In addition, even if the liquid level W is wavy, it is not affected by the reception of the detection light necessary for oil film detection.

  Further, the oil film detector main body 2A obtains the intensity information of the laser beam L5 by converting the laser beam L5 received by the light receiving unit 400 into a predetermined signal, and calculates the reflectance of the liquid surface W; A judgment unit 600 as an example of an acquisition means for acquiring the presence of an oil film on the liquid surface W based on the calculation result by the calculation unit 500 or the intensity information of the laser light L5, and the oil film on the liquid surface W by the judgment unit 600 And a notification unit 700 configured to notify the user when it is determined that there is a presence.

Here, as the laser light source 100, an example configured by a laser diode (not shown) and a drive circuit (not shown) that controls so that a predetermined voltage is applied to the laser diode can be considered.
The configurations of the irradiation unit 200 and the coaxial incident unit 300 are as described above.
As the light receiving unit 400, an example may be considered in which the light receiving unit 400 is configured by a light collecting lens (not shown) for collecting the laser light L5, and a photo diode (not shown) converting the electric light according to the intensity of the collected light.

Further, the arithmetic unit 500 and the determination unit 600 are not illustrated, which are used as a central processing unit (CPU) (not shown) that executes digital arithmetic processing according to a predetermined operation control program (firmware) and a working memory of the CPU. An example may be considered that is configured by a RAM (Random Access Memory) and a ROM (Read Only Memory) (not shown) in which various types of data used in a processing program and a processing program executed by the CPU are stored.
The notification unit 700 may be configured as a display screen (not shown) for visually notifying the user visually, and may be configured as a communication interface for notifying a remote user by a general-purpose communication means. An example is conceivable.

FIG. 2 is a block diagram showing a configuration example of another oil film detector main body 2B of the oil film detector 1. The basic configuration of the oil film detector main body 2B is the same as that of the oil film detector main body 2A (see FIG. 1) described above, so the same reference numerals may be used for the same configuration, and the description may be omitted. .
An oil film detector main body 2B of the oil film detector 1 shown in FIG. 2 includes a laser light source 100, an irradiation unit 200, a coaxial incident light unit 300, a light reception unit 400, a calculation unit 500, a judgment unit 600, and a notification unit 700. The coaxial incident unit 300 has a half mirror 310. The configuration of such an oil film detector main body 2B is common to that of the oil film detector main body 2A.

  Here, a configuration in which the oil film detector main body 2B is different from the oil film detector main body 2A will be specifically described. The coaxial incident portion 300 provided in the oil film detector main body 2B transmits the half mirror 310 and irradiates the detection light to the liquid surface W, and at the same time the half mirror 310 reflects it and the detection light enters the light receiving portion 400. It is different from the coaxial light emitting part 300 provided in the oil film detector main body 2A which reflects the light by the mirror 310 and irradiates the detection light to the liquid surface W and transmits the half mirror 310 and makes the detection light enter the light receiving part 400.

  That is, in the coaxial incident portion 300 included in the oil film detector main body 2B, the laser beam L3 irradiating the liquid surface W is transmitted through the half mirror 310, and the laser beam L5 received by the light receiving unit 400 is the half mirror 310. It is a reflection. In other words, in the coaxial incident unit 300 included in the oil film detector main body 2B, the laser beam L2 from the irradiating unit 200 is transmitted to the half mirror 310, and the transmitted laser beam L3 is totally reflected to the liquid surface W The laser beam L4 that has been guided and totally reflected by the liquid surface W is reflected by the half mirror 310, and the reflected laser beam L5 is guided to be received by the light receiving unit 400.

[Significance of this embodiment]
Here, for example, when the condensate pit is at a relatively high temperature of about 70 or 80 degrees Celsius, steam rises from the liquid level W, and when the condensate pit is semi-sealed, the pit is steamed. May fill up. In such a case, when the laser light from the oil film detector 1 reciprocates between the liquid surface W and the liquid surface W, the laser light is irregularly reflected and the laser light is attenuated, so that the detection result by the oil film detector 1 becomes unstable. . It is conceivable to use air (compressed air) for removing the obstacle substance in order to stabilize the detection result even in the environment where the obstacle substance such as steam or the like adversely affects the detection result. That is, it is a method of reducing the harmful substance floating in the space between the oil film detector 1 and the liquid surface W with air of a predetermined pressure, and suppressing an adverse effect caused by the harmful substance.
However, if it is necessary to supply an amount of air to remove obstacles in the space including the optical path of the laser light, and the oil film detector 1 is not provided with such an air supply device, the detection result is It becomes difficult to stabilize. In addition, although it is conceivable to add an air supply device to the oil film detector 1, the air supply device is enlarged, a large installation space is required, and further, the unit is increased in size and price by integration of the device (high It is assumed that the initial cost). In addition, it is also assumed that a large running cost is required to operate the air supply device because the air consumption is increased.
Therefore, in the present embodiment, a configuration is provided that can reduce the amount of obstacles between the oil film detector 1 and the liquid surface W to reduce the amount of air required to reduce the influence on the detection result.
Hereinafter, as a specific configuration in the present embodiment, the first embodiment and the second embodiment will be described.

First Embodiment
FIG. 3 is a schematic view for explaining the oil film detector 1 according to the first embodiment, and is partially broken. The oil film detector 1 according to the present embodiment includes any one of the above-described oil film detector main bodies 2A and 2B.
As shown to the same figure, the oil film detector 1 is equipped with the food | hood 3 as an example of the surrounding member provided below oil film detector main body 2A, 2B. The hood 3 surrounds the optical path of the laser beams L3 and L4 (see FIG. 1 or FIG. 2) traveling between the oil film detector bodies 2A and 2B and the liquid surface W.
The hood 3 of the oil film detector 1 may be attached to the oil film detector bodies 2A and 2B, and the hood 3 may be attached to another member to determine the position relative to the oil film detector bodies 2A and 2B. Also, a configuration in which the hood 3 is attached to the attached side so as to be removable may be adopted so that the user can attach or detach according to the situation. That is, the oil film detector 1 may be configured to include the hood 3 or may not include the hood 3.

The hood 3 includes a tubular hood body 31, and one end 31 a and the other end 31 b of the hood body 31 are open. An internal space A is formed on the inner peripheral surface side of the hood main body 31 by the cylindrical shape of the hood main body 31.
The hood 3 extends vertically in the attached state. Then, one end 31a of the hood main body 31 is located on the oil film detector main body 2A, 2B side, and the window part 800 where the emission of the laser light L3 and the incidence of the laser light L4 are performed in the oil film detector main 2A, 2B (FIG. Or see Figure 2). In the attached state of the hood 3, the open end 31a is closed by the oil film detector main bodies 2A and 2B. Further, the other end 31 b of the hood body 31 is located on the liquid level W side. Hereinafter, the one end 31a may be referred to as the upper end 31a, and the other end 31b may be referred to as the lower end 31b.

If it explains further, hood 3 is provided with partition part 32 located in interior space A of hood main part 31. As shown in FIG. The partition portion 32 has an inner cylindrical portion 32a having a cylindrical shape smaller than the hood main body 31 and open at both ends, and a connection portion 32b connecting the inner cylindrical portion 32a and the inner peripheral surface of the hood main body 31 to each other. (Double cylinder structure).
The connection portion 32 b is located between the inner cylindrical portion 32 a and the hood main body 31 and is connected to the lower end of the inner cylindrical portion 32 a, and is formed over the entire circumference of the cylindrical shape. For this reason, in the internal space A of the hood main body 31, the upper space and the lower space of the partition part 32 are connected by the opening of the inner cylinder part 32a. The partition part 32 is an example of a partition member.
In the present embodiment, both the hood main body 31 and the inner cylindrical portion 32a have a cylindrical shape with a circular cross section, but the present invention is not limited to this, and a cylindrical example with a cross section other than a circular shape is also possible. Conceivable.

The hood 3 includes an aspirator (intake device) 33 for supplying air (compressed air) compressed by a compressor or the like to the internal space A of the hood main body 31. The aspirator 33 has a supply port 33a to which an air supply pipe (not shown) from a compressor or the like is connected, an intake port 33b for taking in external air (air, air), and an inlet 33c located in the internal space A; Have. Then, the aspirator 33 takes in the outside air from the intake port 33b by forming a pressure-reduced state using the air supplied from the supply port 33a, and guides the outside air to the internal space A from the inlet 33c together with the air. That is, the air-fuel mixture in which the air and the outside air are mixed is led to the internal space A from the inlet 33 c.
By using such an aspirator 33, even if the amount of air supplied from the supply port 33a is small, a large amount of air can be introduced to the internal space A, and a reduction in air consumption can be realized. is there. The aspirator 33 is an example of a supply means.

  The air-fuel mixture (air and outside air) introduced to the internal space A is required to remove various particulates in the air, to be free from rust and the like in the pipe, and the like. High cleanliness may be required. Therefore, in such a case, for example, it is conceivable to provide an air filter at the intake 33 b of the aspirator 33.

The inlet 33 c of the aspirator 33 is located near the upper end 31 a of the hood 3 and the lower end 31 b is open, so that the air-fuel mixture introduced to the internal space A by the aspirator 33 is from the lower end 31 b of the hood 3 Exhausted. That is, in the internal space A of the hood 3, a flow of air-fuel mixture going from the top to the bottom is formed. For this reason, the steam from the liquid surface W is suppressed from entering the internal space A of the hood 3.
Further, since the mixture of air and outside air is blown out relatively vigorously from the lower end 31 b of the hood 3, the mixture between the lower end 31 b of the hood 3 and the liquid level W can reach the liquid level W. Drive away. For this reason, the amount of air present between the oil film detector main bodies 2A and 2B and the liquid surface W can be reduced with a smaller amount of air than in the conventional case, and it is possible to reduce the adverse effect of the light on the detection result.

  Here, the air or the like guided from the inlet 33 c of the aspirator 33 is directed to the inner cylindrical portion 32 a of the partition 32. Since the connection portion 32b is provided at the lower end of the inner cylindrical portion 32a, air and the like can not go downward, and for example, a flow of moving upward in the circumferential direction of the inner cylindrical portion 32a is formed. That is, air or the like from the introduction port 33c of the aspirator 33 can rise in the internal space A to reduce the fogging of the windows 800 of the oil film detector main bodies 2A and 2B.

More specifically, the windows 800 of the oil film detector main bodies 2A and 2B located above the liquid surface W from which steam is released are prone to dew condensation, which adversely affects the detection result. For example, condensation is prevented by heating the window portion 800 with a heater. However, in the case of heater heating, the consumption of electricity increases, which is not preferable. Therefore, in the present embodiment, before discharging the mixture of air and the outside air from the lower end 31 b of the hood 3, the mixture is directed to the window 800 to thereby eliminate condensation on the window 800, and heater heating is performed. Even without it, the adverse effect of the detection result due to condensation is prevented.
As a matter of course, it is also conceivable to use the heater heating in combination with the prevention of condensation by air-fuel mixture, in which case the heater heating may be reduced, and power consumption can be suppressed.
In addition, although a configuration in which the upper end 31a of the hood 3 is opened is adopted in the present embodiment, it is conceivable to suppress condensation by two sheets of glass by providing a transparent member such as glass at the upper end 31a.

Second Embodiment
Next, an oil film detector 1 according to a second embodiment will be described. The oil film detector 1 according to the second embodiment has the same configuration as the first embodiment described above, so the same configuration may be used with the same reference numerals, and the description thereof May be omitted.
FIG. 4 is a schematic view for explaining the oil film detector 1 according to the second embodiment, and is partially broken away as in the case of FIG.
As shown in FIG. 4, the oil film detector 1 according to the second embodiment includes the hood 3 in addition to any one of the oil film detector main bodies 2A and 2B as in the case of the first embodiment. .
The hood 3 includes the cylindrical hood body 31 described above, and an inner space A is formed on the inner peripheral surface side.
Unlike the first embodiment, the hood 3 does not include the partition 32 and the aspirator 33.

  To explain further, the hood 3 is provided with an L-shaped connector 34 to which an air supply pipe (not shown) for supplying air compressed by a compressor or the like is connected. The connector 34 has a supply port 34 a to which an air supply pipe is connected, and an introduction port 34 b located in the internal space A. The inlet 34 b is directed downward toward the lower end 31 b of the hood body 31. For this reason, the air of the supply port 34a is discharged downward from the inlet 34b. In the internal space A, air flowing downward is formed by the air, whereby the steam existing between the lower space 31 b of the internal space A and the hood 3 and the liquid surface W is pushed, and the adverse effect due to the steam can be reduced.

  More specifically, the hood 3 is provided with a vent 35 formed at a position closer to the upper end 31 a than the connector 34 in the hood body 31. A plurality of such vents 35 are formed at intervals along the circumferential direction of the hood body 31. The downward air flow in the internal space A causes the ejector effect to draw in the outside air from the air vent 35. For example, assuming that the air is 1, the outside air becomes about 6, and the amount of air discharged from the lower end 31b of the hood main body 31 increases, and steam is efficiently used without using the aspirator 33 in the first embodiment. Can be eliminated. The connector 34 and the vent 35 of the hood body 31 are an example of a supply means.

  Further, since the vent 35 of the hood 3 is at a position close to the window 800 of the oil film detector main bodies 2A and 2B, the outside air from the vent 35 acts to suppress condensation on the window 800. For this reason, even in the case of the second embodiment, it is possible to prevent an adverse effect associated with dew condensation on the window portion 800.

As described above, although the oil film detector 1 has been described as the present embodiment, the present invention is not limited thereto, and can be applied to other detectors, for example, a water level gauge that detects the height of the liquid surface W . Moreover, the present invention can be applied to optical analysis devices other than the oil film detector 1.
In addition to operating the compressor or the like that supplies air to the hood 3 at all times, and also when controlling the operation of the compressor in accordance with the operation timing of the detector when it is not necessary to always operate the detector. Conceivable. That is, this is a modification in which the operation of the compressor or the like starts before the measurement, and the operation of the compressor or the like is stopped after the measurement.

[Confirmation experiment]
FIG. 5 is a diagram for explaining an experiment for confirming the effect according to the present embodiment, in which (a) is a diagram for explaining an experimental apparatus, and (b) is a table showing experimental results.
As shown in FIG. 5A, the oil film detector main body 2A to the oil film detector main body 2B are disposed on the upper side of the hot plate 42. The water is heated to about 100 degrees by the hot plate 42 and steam rises from the hot plate 42.
The cylindrical hood 41 is disposed under the window 800 (see FIG. 3 or 4) of the oil film detector main bodies 2A and 2B. Also, downward air supply (purge) was performed from between the oil film detector main bodies 2A and 2B and the hood 41. The downward air flow of the purge removes the steam of the hot plate 42 from the internal space A of the hood 3 and the space between the hood 3 and the hot plate 42.
In this experimental device, the diameter of the hood 3 was 125 mm, and the distance L between the hood 3 and the liquid surface of the hot plate 42 was in the range of 500 mm to 1100 mm.

As shown in FIG. 5 (b), the detection level (DETECT LEVEL) at a distance L of 500 mm and the detection level (DETECT LEVEL) at a distance L of 110 mm, without purge / condensation in the case of ordinary temperature water, which is reflection intensity at normal times. It measured separately in the case without purge (immediately after the start of measurement), with purge / with condensation, and with purge / without condensation.
In the case of normal temperature water, there is almost no difference between the case where the distance L is 500 mm and the case where the distance L is 1100 mm. And although there is no detection immediately after the start of measurement / no condensation, the detection level is lower than that of normal temperature water, the difference between the case where the distance L is 500 mm and the case where the distance L is 1100 mm is slightly to some extent. In the case of no purge / condensation, the detection level decreased significantly. And, in the case of with purge / without condensation, it recovered almost to the detection level immediately after the start of measurement.
As described above, without the purge, dew condensation occurs in the window 800 (see FIG. 3 or FIG. 4), and the detection level decreases. On the other hand, when the purge occurs, the dew condensation disappears and the detection level returns. Experiments have shown that air supply suppresses the decrease in detection level.

  And, in the present embodiment, as described above, by utilizing the pressure reducing action by the aspirator 33 (first embodiment) or the ejector effect by the air and the vent 35 (second embodiment), the hood The outside air is taken into the internal space A in 3. As a result, it is possible to secure a larger flow rate in the internal space A with a small amount of air supply, and suppress the adverse effect of steam on the detection results of the oil film detector main bodies 2A and 2B while suppressing the air consumption. It becomes possible.

DESCRIPTION OF SYMBOLS 1 ... oil film detector, 3 ... hood, 32 ... partition part, 33 ... aspirator, 34 ... connection tool, 35 ... vent, 100 ... laser light source, 400 ... light receiving part, 600 ... judgment part, W ... liquid surface

Claims (3)

An output means for outputting a detection light;
A light receiving means for receiving the light reflected by the detection surface of the detection light of the output means;
Acquisition means for acquiring information on the detected surface based on information of the reflected light received by the light receiving means;
An enclosing member extending in a direction of an optical path of the reflected light and surrounding the optical path of the reflected light;
It is a supply means which supplies air inside the said enclosure member, Comprising: While supplying air toward the direction of the said to-be-detected surface inside the said enclosure member, the pressure action accompanying supply of air supplies the air of the said enclosure member Supply means for supplying the outside air with the air to the inside of the enclosing member;
A detector comprising:   The surrounding member is an inner side of the surrounding member such that air and air supplied to the inside of the surrounding member by the supply means are directed in the direction opposite to the detection surface and then in the direction of the detection surface The detector according to claim 1, further comprising a partition member that divides a space. A hood used together with a detector for detecting information related to the detected surface based on information of reflected light from the detected surface, comprising:
The hood is
Extending in the optical path direction of the reflected light to surround the optical path of the reflected light;
When air is supplied to the inside of the hood so that the air is directed toward the detection surface, air outside the hood can be supplied to the inside together with the air by the pressure action accompanying the supply. Food characterized by

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