JP2000019103A - Oil film detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably protect a light projecting means and a light receiving means from water splash and dust for a long period of time so as to make stable, continuous measurement possible by arranging optical windows and water barrier plates respectively between the light projecting means and the water surface and between the light receiving means and the water surface. SOLUTION: The general function of this device is the same as a conventional oil film detecting device. In the conventional function, however, in the case of being installed in a place with large waves or continuously operated for a long period of time, light projecting and receiving means are exposed to splashed water and polluted with water scale and dust to cause an error in polarization ratio measurement. In order to protect a laser beam source 1 and a light receiving means 6 in this device, an optical window 15 and a water barrier plate 15 are therefore installed between the laser beam source 1 and the water surface 4, and an optical window 17 and a water barrier plate 18 are installed between the light receiving means 6 and the water surface 18. The material of the optical windows 15, 17 is optical glass, and the water barrier plates 16, 18 are of double structure with small holes opened in the center of conical shape to make optical beams pass through. These water barrier plates 16, 18 shut out most of water splash and suppress the entry of dust.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus for detecting an oil film on a water surface. More specifically, the present invention relates to an oil film detecting device that automatically detects an oil component flowing into a water purification plant, a farm, or the like, or an oil component flowing out of a factory drainage facility or the like as an oil film on the water surface.

[0002]

2. Description of the Related Art In a water purification plant, oil pollution of raw water accounts for about half of water quality accidents, which is a serious accident that requires the suspension of water intake and cleaning of the water purification plant. Due to the risk of product contamination or death, there is a need for a method and apparatus for constantly monitoring the flow of oil into these water intakes. On the other hand, in factory wastewater,
Draining oil-laden wastewater into public waters is a social problem as water pollution, and it is necessary to meet wastewater standards.Consecutively monitor whether oil is left in treated wastewater. There is a need for a method and apparatus for doing so.

[0003] As a method of automatically detecting the inflow of oil into the water intake at a water purification plant, there have been conventionally used (1) a reflectance measurement method,
(2) An image monitoring method using a TV camera is known. In addition, as a method for detecting oil in factory wastewater, for example,
(3) Hexane extraction / gravimetric method (JIS K0101, J
IS K0102), (4) Extraction and infrared absorption measurement method (JIS K0101, JIS K0102), (5)
Emulsification and turbidity measurement methods and (6) fluorescence measurement methods are known.

However, it has been pointed out that these oil detecting devices have problems such as difficulty in continuous automatic measurement, difficulty in detecting a trace amount of oil, and many malfunctions.
In order to solve these problems, (7) an oil film detecting device based on ellipsometry has been filed by the present applicant as Japanese Patent Application No. 9-90453. FIG. 6 shows an example of the configuration of this conventional oil film detecting device based on (7) ellipsometry, and the outline of the measurement principle will be described below.

In this figure, a light beam 2 from a laser light source 1 is applied obliquely to a wavy water surface 4 on which an oil film 3 floats. The reflected light 5 from the water surface 4 is scattered in various directions due to the waving of the water surface, and the reflected light reflected at a certain angle is received by the pinhole-shaped light receiving means 6. The received light is split by a polarization beam splitter 7 into a P-polarized component 8 and an S-polarized component 9. Separated P-polarized component 8
And the S-polarized component 9 are photoelectrically converted by the photodiode 10 and the photodiode 11, respectively, and each light amount is converted into an electric signal. After each electric signal is amplified by the amplifier 12 and the amplifier 13, it is input to the arithmetic circuit 14. The arithmetic circuit 14 calculates the light amount ratio of the P-polarized light component and the S-polarized light component (hereinafter referred to as a polarization ratio), and compares the polarization ratio with a reference value in a normal state where there is no oil film on the water surface to determine the presence or absence of an oil film. I do. The definition of the P-polarized light component and the S-polarized light component in the above description is parallel to the plane including the normal line of the water surface and the incident light axis set at the point where the incident optical axis of the light beam 2 intersects the flat water surface without waves. The polarized light component is a P-polarized light component, and the perpendicular polarized light component is an S-polarized light component.

In the above-described apparatus, the oil film is detected by utilizing the difference between the P-polarized light component and the S-polarized light component of the reflected light between the water surface having an oil film and the water surface having no oil film. Light, which is an electromagnetic wave, is a transverse wave that oscillates in a plane perpendicular to the propagation direction. From its characteristics, it can be considered that the P-polarized light component and the S-polarized light component are independently reflected on the water surface. The intensity of the reflected light is defined by the reflection coefficient of Fresnel, and varies independently depending on the angle of incidence of the light beam and the refractive index (or dielectric constant) of the medium. Therefore, when an oil film is present on the water surface, the reflected light intensities of the P-polarized light component and the S-polarized light component change independently of each other due to the difference in the refractive index between oil and water. Therefore, the P-polarized light component and the S-polarized light component of the reflected light are separated, and the respective reflected light intensities are measured. When the ratio is taken, the value changes depending on the presence of the oil film, so that the oil film can be detected. it can.

The feature of this means is that since it is an optical measurement, the oil film can be easily and continuously detected without a complicated operation, and it is hardly affected by ripples on the water surface and floating foreign substances. To detect the oil film with high sensitivity. If the water surface is wavy or foreign matter floats, irregularly reflected light is generated. Therefore, if the intensity of the reflected light is simply monitored, the intensity changes and stable measurement cannot be performed, resulting in a decrease in sensitivity. On the other hand, if the ratio between the P-polarized component and the S-polarized component is monitored, the ratio of the polarized component is maintained as long as light is received at a constant reflection angle, even if the surface of the water ripples and the intensity of the reflected light changes. Since it is hard to change, stable and highly sensitive measurement can be performed. Also, when there is a foreign substance floating on the water surface, the ratio of the S-polarized component divided by the P-polarized component is larger than that of water due to the presence of the oil film. In this case, since the polarized light is eliminated and the ratio becomes smaller, the difference between the oil film and the foreign matter can be determined.

[0008]

The oil film detecting device based on the above-mentioned ellipsometry is hardly affected by the ripples on the water surface.
Oil film can be monitored continuously with high sensitivity. However, in the case of installation in a place where the waves are large, water splashes on the light projecting part and the light receiving part, so that it was necessary to install an optical window. However, when the optical window is operated continuously for a long period of time, there is a problem that the optical window is contaminated with scale and dust, and the scale and dust depolarize the light beam, thereby causing an error in the measurement of the polarization ratio. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve this problem, and an object of the present invention is to provide an oil film detecting device using an ellipsometry, which is provided with a light projecting unit which is capable of detecting water droplets and dust generated by waving of the water surface. An object of the present invention is to provide an oil film detection device that stably protects a light receiving unit for a long period of time and enables stable continuous measurement.

[0010]

According to a first aspect of the present invention, there is provided an oil film detecting apparatus based on an ellipsometry, which protects a light projecting portion and a light receiving portion from water splashes caused by waving of the water surface. As a method, a light projecting unit and a light receiving unit provided with an optical window, and one or more stages of water blocking plates disposed between the optical window and the water surface are employed as technical means.

[0011] In the first device, since the water shield plate is provided together with the optical window, most of the water splash is blocked by the water shield plate, and it becomes difficult for dust to enter. Long term stable protection and stable continuous measurement of oil film. In a second device of the present invention, in an oil film detection device based on ellipsometry, as a method of protecting the light projecting portion and the light receiving portion from water splashes caused by the waving of the water surface, an optical window and an air blower device for blowing air to the optical window are provided. The light-emitting unit and the light-receiving unit provided with are adopted as technical means.

In the second device, since the air blower device is provided together with the optical window, water splash and dust attached to the optical window can be blown off by the air blow, so that the light projecting portion and the light receiving portion can be stably protected for a long period of time. And stable continuous measurement of the oil film can be performed. According to a third device of the present invention, in an oil film detecting device based on ellipsometry, as a method of protecting the light projecting portion and the light receiving portion from water splashes caused by the waving of the water surface, an air window is provided between the optical window, the optical window and the water surface. A light projecting unit and a light receiving unit provided with an air blower device for forming a curtain are employed as technical means.

In the third device, since an air blower device for forming an air curtain together with the optical window is provided, water splashes and dust flying toward the optical window can be blocked by the air curtain. The unit and the light receiving unit can be protected stably for a long time, and stable continuous measurement of the oil film can be performed. In a fourth device of the present invention, in an oil film detection device based on ellipsometry, as a method of protecting the light projecting portion and the light receiving portion from water splashes caused by the waving of the water surface, an ultrasonic window for vibrating the optical window and the optical window is used. The light-emitting unit and the light-receiving unit provided with the device are adopted as technical means.

In the fourth device, since the ultrasonic transmitter is provided together with the optical window, water splashes and dust attached to the optical window can be removed by ultrasonic vibration. Stable protection and stable continuous measurement of oil film. In a fifth embodiment of the present invention, in an oil film detecting device based on ellipsometry, as a method for protecting the light projecting portion and the light receiving portion from water splashes caused by the waving of the water surface, an optical window coated with a titanium oxide film and its optical window are used. A light projecting unit and a light receiving unit provided with a light irradiation device for irradiating the window with ultraviolet light are employed as technical means.

In the fifth device, since the titanium oxide film-coated optical window and the ultraviolet irradiation device are provided, the titanium oxide film decomposes organic substances which cause fixation of dirt by irradiation of ultraviolet rays, and fixes dust and scale. prevent. Further, since the contact angle with water is small, the splashed water does not become a water droplet but a thin film on the optical window, so that the influence of depolarization of the light beam can be reduced. Therefore, the light projecting unit and the light receiving unit can be stably protected for a long time, and stable continuous measurement of the oil film can be performed.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on five embodiments. Embodiment 1 FIG. 1 shows an oil film detecting device as a first embodiment of the present invention. In this figure, the same components as those shown in FIG. 6 indicate the same components.

The embodiment of the present invention is different from the conventional oil film detecting apparatus shown in FIG. 6 in that an optical window 15 and a water blocking plate 16 are provided between the laser light source 1 and the water surface 4, and the light receiving means 6 and the water surface 4 are provided. An optical window 17 and a water shield plate 18 have been added between them. Optical window 1
The materials 5 and 17 are optical glass (BK7). The water blocking plates 16 and 18 are doubled and have a structure in which a small hole for passing a light beam is formed at the center of the cone. The water shield plate blocks most of the water splashes and makes it difficult for dust to enter, so that the light emitting unit and the light receiving unit can be protected stably for a long period of time, and stable continuous measurement of the oil film can be performed. [Embodiment 2] Fig. 2 shows an oil film detecting apparatus according to a second embodiment of the present invention. In this figure, the same components as those shown in FIG. 6 indicate the same components.

The embodiment of the present invention is different from the conventional oil film detecting apparatus shown in FIG. 6 in that an optical window 15 and an air blower 19 are provided between the laser light source 1 and the water surface 4, and an optical window 15 is provided between the light receiving means 6 and the water surface 4. The optical window 17 and the air blower 20 have been added.
The air blowers 19 and 20 have built-in air pumps, and blow air vigorously onto the optical windows 15 and 17 from finely squeezed air outlets. As a result, water droplets and dust attached to the optical window can be blown off, so that the light emitting unit and the light receiving unit can be stably protected for a long period of time, and stable continuous measurement of the oil film can be performed. [Embodiment 3] FIG. 3 shows an oil film detecting apparatus according to a third embodiment of the present invention. In this figure, the same components as those shown in FIG. 6 indicate the same components.

The embodiment of the present invention is different from the conventional oil film detecting device shown in FIG. 6 in that an optical window 15 and an air blower 21 are provided between the laser light source 1 and the water surface 4, and an optical window 15 is provided between the light receiving means 6 and the water surface 4. The optical window 17 and the air blower 22 have been added.
The air blowers 21 and 22 have a plurality of minute air outlets arranged in series, and the air outlets discharge air in a direction perpendicular to the optical axis, forming an air curtain for the optical window. Since the water curtain and dust flying toward the optical window can be blocked by the air curtain, the light emitting unit and the light receiving unit can be stably protected for a long period of time, and stable continuous measurement of the oil film can be performed. Fourth Embodiment FIG. 4 shows an oil film detecting device according to a fourth embodiment of the present invention. In this figure, the same components as those shown in FIG. 6 indicate the same components.

The embodiment of the present invention is different from the conventional oil film detecting apparatus shown in FIG. 6 in that the optical window 15 and the small ultrasonic transmitter 23 are provided between the laser light source 1 and the water surface 4, and the light receiving means 6 and the water surface are provided. 4, an optical window 17 and a small ultrasonic transmitter 24 have been added. The ultrasonic transmitters 23 and 24 are in contact with the optical windows 15 and 17, respectively, apply high-speed micro vibration to the optical windows, and remove water splashes and dust attached to the optical windows. As a result, the light emitting unit and the light receiving unit can be stably protected for a long period of time, and stable continuous measurement of the oil film can be performed. [Embodiment 5] FIG. 5 shows an oil film detecting apparatus according to a fifth embodiment of the present invention. In this figure, the same components as those shown in FIG. 6 indicate the same components.

The embodiment of the present invention differs from the conventional oil film detecting device shown in FIG. 6 in that the optical window 25 and the optical window 2 coated with a titanium oxide film between the laser light source 1 and the water surface 4 are different.
A light irradiation device 26 for irradiating ultraviolet rays to the optical window 2, and an optical window 2 coated with a titanium oxide film between the light receiving means 6 and the water surface 4.
7 and a light irradiation device 28 for irradiating the optical window 27 with ultraviolet light. The titanium oxide coating is applied by a sol-gel method to maintain surface accuracy. The titanium oxide film decomposes organic substances that cause dirt to be fixed by irradiation with ultraviolet rays and prevents dust from being fixed. Further, since the contact angle with water is small, the splashed water does not become a water droplet but a thin film on the optical window, so that the influence on the polarization characteristics of the light beam can be reduced. Therefore, the light projecting unit and the light receiving unit can be stably protected for a long time, and stable continuous measurement of the oil film can be performed.

In this embodiment, the laser light source 1 is used as the light projecting means for irradiating the water surface with a light beam. However, when an ultraviolet lamp is used as the light projecting means, the optical window 2 is used.
The light irradiation devices 26 and 28 for irradiating the ultraviolet rays 5 and 27 with ultraviolet rays can be omitted. The installation method of the oil film detecting device is not shown in the drawings of the first to fifth embodiments, but is fixed around the water tank in which the water level does not change, and is mounted on a floating float in a river or ocean where the water level changes. It is possible to adopt a method of floating and setting.

When there is an influence of disturbance light such as sunlight, an interference filter for passing only the wavelength of the projected beam is provided in front of the photoelectric converter of the light receiving section, or the modulated beam is modulated by modulating the projected beam. Only the signal processing section
The effect of disturbance light can be eliminated. In the embodiment, a light beam containing both a P-polarized component and an S-polarized component is used. However, a light beam having a P-polarized characteristic and a light beam having an S-polarized characteristic are alternately irradiated using two laser light sources. hand,
Even if the polarization beam splitter 12 is omitted and the intensity of the P-polarized light component and the S-polarized light component of the reflected light is measured by one photoelectric converter 15, the same performance as that of the embodiment can be obtained.

[0024]

According to the oil film detecting device of the present invention, the light projecting portion and the light receiving portion are contaminated by water droplets and dust generated by the waving of the water surface, which is a problem of the conventional device, and stable continuous measurement can be performed for a long time. In order to solve the problem of not having, an optical window is provided, and an air blower device that blows air to one or more stages of a water shielding plate or an optical window disposed between the optical window and the water surface, Using an air blower that forms an air curtain between the optical window and the water surface, an ultrasonic transmitter that vibrates the optical window, and an optical window coated with a titanium oxide film, The light section and the light receiving section can be stably protected for a long time. As a result, stable continuous measurement of the oil film became possible.

[Brief description of the drawings]

FIG. 1 is a schematic view of a first invention example of an oil film detection device.

FIG. 2 is a schematic view of a second invention example of an oil film detection device.

FIG. 3 is a schematic view of a third invention example of an oil film detection device.

FIG. 4 is a schematic view of a fourth invention example of an oil film detection device.

FIG. 5 is a schematic view of a fifth invention example of an oil film detection device.

FIG. 6 is a schematic diagram of a conventional oil film detection device.

[Explanation of symbols]

 1: laser light source 2: light beam 3: oil film 4: water surface 5: reflected light 6: light receiving means 7: polarization beam splitter 8: P-polarization component 9: S-polarization component 10, 11: photodiode 12, 13: amplifier 14: Arithmetic circuit 15, 17: Optical window 16, 18: Water barrier 19, 20: Air blower 21, 22: Air blower 23, 24: Ultrasonic transmitter 25, 27: Titanium oxide coating optical window 26, 28: Light irradiation device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Inui Takashi 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-city, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Masakatsu Fukuda 1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-ku, Kanagawa Prefecture No. 1 Fuji Electric Co., Ltd. (72) Inventor Hiroshi Tada 1-1-1 Tanabe Shinda, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture F-term in Fuji Electric Co., Ltd. (reference) NN07 PP01

Claims (5)

[Claims] 1. A light projecting means for irradiating a light beam to a water surface on which an oil film floats, a light receiving means for receiving light reflected from the water surface at a specified reflection angle, and an incident optical axis for receiving the reflected light. A polarization component parallel to a plane including the normal line of the water surface and an incident optical axis (hereinafter referred to as a P-polarization component) and a polarization component perpendicular to the plane (hereinafter referred to as an S-polarization component)
Oil film detection, comprising: a polarization separation means for dividing the light into light and a measuring means for measuring the light amounts of the separated P-polarized light component and the S-polarized light component. In the apparatus, the light projecting means and the light receiving means include an optical window, and one or more stages of water blocking plates arranged between the optical window and the water surface. 2. An oil film detecting apparatus according to claim 1, wherein said light projecting means, said polarization separating means, and said measuring means comprise: an optical window; An oil film detection device comprising an air blower for blowing. 3. An oil film detecting apparatus according to claim 1, comprising: a light projecting means, a polarization separating means, and a measuring means, wherein said light projecting means and said light receiving means are formed of an optical window, an optical window and a water surface. An oil film detecting device comprising an air blower means for forming an air curtain therebetween. 4. An oil film detecting apparatus comprising: the light projecting means, the polarization splitting means, and the measuring means according to claim 1, wherein the light projecting means and the light receiving means vibrate an optical window and an optical window. An oil film detection device comprising an ultrasonic transmitter. 5. An oil film detecting apparatus comprising: a light projecting device according to claim 1; a polarization separating device; and a measuring device, wherein the light projecting device and the light receiving device have an optical window coated with a titanium oxide film. An oil film detecting device, comprising: a light irradiation means for irradiating the optical window with ultraviolet light.