JP2002214140A - Oil film detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescence detection type oil film detection device capable of discriminating an oil film which is a measuring object from a solid material emitting fluorescence, and detecting only the oil film selectively with high sensitivity. SOLUTION: This oil film detection device by fluorescence spectrometry is equipped with an excitation light irradiation means 1 for irradiating the water surface W with excitation light, a fluorescence reception means 2 for measuring the fluorescence intensity of the fluorescence emitted from the water surface W, a reflected light reception means 3 for measuring the reflected light intensity reflected by the water surface W, and an operation means 4 for determining existence of the oil film M from the fluorescence intensity and the reflected light intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil film detecting device for detecting an oil component on a water surface such as a river, a lake or a dam.

[0002]

2. Description of the Related Art Water supplies use water from rivers, lakes, marshes, dams, and the like. However, contamination of water sources is a problem because it leads to accidents. In particular, contamination of water sources by oil spills accounts for the majority of actual water accidents. If oil is mixed into the water supply, oil odor damage will occur first, and the facilities in the water treatment plant will be contaminated with oil, and the treatment will require a lot of cost and time. Therefore, we will detect in advance the contamination of the water source with oil,
It is important to prevent oil from flowing into the water treatment plant.

Since the spilled oil exists on the water surface as an oil film, the presence of the oil can be confirmed by detecting the oil film. Conventionally, personnel are placed at the water intake to visually monitor the water surface, or an image of the water surface captured by a TV camera is transmitted to the monitoring room of the water purification plant, and the staff observes and monitors the image. Had gone. Observation of the inflow of oil requires constant observation for 24 hours. Therefore, human observation imposes a heavy burden on the observer, and increasing the number of personnel increases labor costs.

[0004] Therefore, a device for continuously detecting an oil film is required. As a detection method capable of continuous monitoring, application of an optical method for detecting oil by measuring the difference between the optical properties of the water surface and oil has been studied, and some of them have been put to practical use. The optical technique currently in practical use is mainly a method of measuring the reflectance of the water surface. This method detects an oil film by using the fact that the reflectance of oil is higher than that of water.

Although the apparatus can be constructed relatively easily in the reflectivity measurement, the intensity of the reflected light entering the light receiver is affected by the waving of the water surface, so that the applicable place is limited to the still water surface. Therefore, the present invention is applied to a water surface having a constant water level with little ripple, such as a landing well or a water channel in a water purification plant or an intake plant. In this case, the entry of oil can be detected after the oil has entered the water supply facility, which is disadvantageous in performing a prompt response after the oil entry.

[0006]

Oil has the property of absorbing light in the ultraviolet range and emitting fluorescence. Therefore, the oil can be detected by irradiating the water surface with ultraviolet light as excitation light and measuring the light intensity of a fluorescence wavelength unique to the oil. In the fluorescence measurement, the oil can be detected with higher sensitivity than in the reflected light measurement. In addition, since the fluorescence emission depends on the physical properties of the material on the water surface and is not affected by the physical shape of the water surface, it can be applied to a wavy water surface. Therefore, it can be applied to environments such as rivers and lakes. By installing an oil detector using fluorescence in a river or lake that serves as a water source for water supply, oil can be detected before flowing into a water supply facility, and more effective measures can be taken more quickly.

[0007] One problem with applying fluorescence spectroscopy to rivers and lakes is that when solids having the same fluorescent properties as oil float on the water surface and enter the measuring range of the detector, the solids are converted to oil. That is, there is a possibility of erroneous recognition. In particular, petrochemical products such as plastics use crude oil as a raw material, and therefore have a similar molecular structure to liquid oil.
This is problematic because the fluorescent properties have a similar tendency.

As a countermeasure against erroneous recognition, it is conceivable to install a fence-shaped or net-shaped trap to prevent solids from entering the measurement range of the detector. In that case, if a trap with a fine eye is installed, clogging may occur due to suspended matter or contamination, and oil may also be captured by the trap, making detection impossible. However, it is impossible to completely remove suspended matter with an open trap, and inflow of suspended matter that may cause false recognition is inevitable.

In view of the above, when applying fluorescence spectroscopy to oil detection in rivers and lakes, it is necessary to distinguish solids from oils by some method in order to prevent erroneous detection due to solids.

[0010] In order to solve the above-mentioned problems, the present invention provides a fluorescence detection type oil film detection device that discriminates an oil film to be measured from a solid substance that emits fluorescence and selectively detects only the oil film with high sensitivity. The purpose is to do.

[0011]

According to one aspect of the present invention, there is provided an oil film detecting apparatus for irradiating excitation light onto a water surface, and measuring an intensity of fluorescence emitted from the water surface. A reflected light receiving means for measuring the intensity of the reflected light reflected from the water surface, and a calculating means for determining the presence or absence of an oil film from the fluorescence intensity and the reflected light intensity.

According to a second aspect of the present invention, in the oil film detecting device according to the first aspect, the excitation light irradiating means is 200 to 30.
Irradiation with excitation light having a wavelength of 0 nm is performed, and
The reflected light receiving means selectively receives light having a wavelength of 400 to 400 nm, and the reflected light receiving means selectively receives reflected light having a wavelength of 200 to 300 nm, which is the same as the excitation light.

The invention according to claim 3 is the invention according to claim 1 or 2
And a beam splitter for separating light from the water surface in two directions, and a first light guide for guiding one of the lights separated by the beam splitter to the fluorescence receiving means.
And a second optical path for guiding the other light separated by the beam splitter to the reflected light receiving means.

According to a fourth aspect of the present invention, there is provided an oil film detecting device for irradiating an excitation light onto a water surface, a beam splitter for separating light from the water surface into two directions, and one optical path of the separated light. A fluorescent filter that selectively transmits light having a fluorescent wavelength of oil, a fluorescent light path shutter that blocks an optical path of light transmitted through the fluorescent filter, and an excitation light that is disposed in the other light path of the separated light. A reflected light filter that selectively transmits light of the same wavelength, a reflected light path shutter that operates reciprocally to the fluorescent light path shutter to block the light path of light transmitted through the reflected light filter, and light separated by the beam splitter , Which guides the light again to the same optical path, photoelectric conversion means for measuring the intensity of light passing through the light collection part, and the presence or absence of an oil film from the fluorescence intensity and reflected light intensity obtained by the photoelectric conversion means. Characterized by comprising a calculating means for.

According to a fifth aspect of the present invention, there is provided an oil film detecting device for irradiating an excitation light to a water surface, an excitation light irradiating means, a fluorescent filter for selectively transmitting light having a fluorescence wavelength of oil emitted from the water surface, Reflected light filter for selectively transmitting light having the same wavelength as the excitation light of the reflected light, filter switching means for selectively positioning the fluorescent filter or the reflected light filter in the reflected light path, the fluorescent filter and the reflected light filter And photoelectric conversion means for photoelectrically converting light transmitted through the light-transmitting device, and calculating means for determining the presence or absence of an oil film from the fluorescence intensity and reflected light intensity obtained by the photoelectric conversion means.

[0016]

Embodiments of the present invention will be described below with reference to tables and figures.

<Embodiment 1> FIG. 1 shows an example of an oil film detecting apparatus according to the present invention. Excitation light is irradiated onto the water surface W from the excitation light irradiation means 1 installed above the water surface W. The excitation light irradiating means 1 includes a light emitting element serving as a light source and an optical filter for selectively transmitting light of a specific wavelength. The optical filter transmits light having a wavelength that can excite the oil, and selectively excites the oil present on the water surface W.
The fluorescent light receiving means 2 also includes an optical filter for selectively transmitting light of a specific wavelength among the light arriving from the water surface W, and a light receiving element. The optical filter on the light receiving side transmits the wavelength of the fluorescence emitted from the oil and cuts the other wavelengths, thereby obtaining the fluorescence emitted from the oil excited by the excitation light.

In fluorescence measurement, it is important to select a wavelength range of an optical filter. Hereinafter, an example of the selection of the wavelength range will be described. Oils are generally known to fluoresce in the ultraviolet range. 260n as excitation light
FIG. 2 shows a fluorescence spectrum of a mineral oil-based mechanical oil when irradiated with light of m.

In FIG. 2, the fluorescence spectrum is observed at 300 to 400 nm, and particularly, there is a strong fluorescence peak near 320 nm. Therefore, oil can be detected by using light in the ultraviolet region of 300 nm or less as excitation light and receiving fluorescence of 300 to 400 nm.

However, a problem is that some solid substances other than oil emit fluorescence at the wavelengths of excitation light and fluorescence for detecting oil. FIG.
Although styrene foam was extracted in hexane solvent,
3 shows a fluorescence spectrum when excited by light of 260 nm.

[0021] The peak of the fluorescence intensity is also observed at around 320 nm for styrofoam, and emits fluorescence similarly to oil. To distinguish these solids from oil slicks,
The reflected light receiving means 3 is installed, receives the reflected light of the excitation light on the water surface W, and measures the reflected light intensity.

Table 1 shows the results for oil slicks and various solids.
The change of the fluorescence intensity and the reflected light intensity with respect to water is shown.

[Table 1]

Table 2 shows the results for oil slicks and various solids.
It is a summary of the responsivity of the fluorescence intensity and the reflected light intensity.

[Table 2]

Here, a mineral oil-based mechanical oil is used as the oil. In the oil film, both fluorescence and reflected light are increasing, but in the case of styrene foam and PE (polyethylene) sheet,
As in the case of the oil, the fluorescence intensity is increased, but the reflected light intensity is decreased. In the case of an oil film, the reflectance is higher than that of water, so that the intensity of reflected light increases. On the other hand, the reflectance of solid solids is lower than that of water, so that the intensity of reflected light decreases. Utilizing the above properties, when the fluorescence intensity increases and the reflected light intensity does not decrease, it is determined that an oil film exists. The above series of measurement and calculation of the measurement result are performed in the light emission control measurement circuit 4.

In oil film detection by fluorescence spectroscopy, light in a wavelength range that excites oil is radiated from the excitation light irradiating means 1 to the water surface W, and fluorescence emitted from the oil is detected by the fluorescent light receiving means. At this time, if the oil film M exists on the water surface W, the fluorescence intensity increases. Therefore, when the fluorescence intensity becomes equal to or more than a predetermined value, it is determined that the oil film M exists. When the oil film M does not exist on the water surface W, no fluorescence is emitted.
Is very small. Therefore, S /
There is a feature that the N ratio is high. On the other hand, in the reflected light measurement method, the constant reflected light intensity due to the water surface W becomes the background, and the increase in the reflected light intensity increased by the oil film M is detected.
Therefore, by applying the fluorescence spectroscopy, it is possible to detect the oil film M with higher sensitivity than the conventional method.
Since it is hardly affected by ripples, it can be installed in rivers and lakes.

When the above-described fluorescence spectroscopy is applied to a river or the like, a solid substance floating on the water surface W may flow into a measurement range of the oil film M detection device. Some of these solids have fluorescent properties similar to oils. Since the fluorescence intensity also increases due to such a fluorescent solid, if the oil film M is detected using only the increase in the fluorescence intensity as an index, the oil film M and the solid may be erroneously recognized.

In order to distinguish these fluorescent solids from the oil film, the reflected light of the water surface W to be measured is measured at the same time. Solid matter that is assumed to float on the water surface W generally has a lower reflectance than water, regardless of the presence or absence of fluorescence. Therefore, when a solid is present, the reflected light intensity is lower than when no solid is present. On the other hand, when the oil film M exists, the reflected light tends to increase.

By utilizing the characteristics of the fluorescent light and the reflected light as described above, it is possible to selectively detect only the oil film M. In the oil film M, both the intensity of the fluorescent light and the reflected light increase, but the intensity of the fluorescent light increases, while the intensity of the reflected light decreases. Therefore,
When the fluorescence intensity increases and the reflected light intensity does not decrease, it is determined that the oil film M exists. By using this method, it is possible to improve the selectivity for the oil film M while maintaining the high sensitivity of the fluorescence spectroscopy.

In fluorescence spectroscopy, the range of the excitation wavelength to be irradiated and the fluorescence wavelength to be received are important. The oil is excited by light in the ultraviolet region of 200 to 300 nm,
It emits fluorescence in the wavelength region of 0 nm. Therefore, the oil can be selectively detected by using the excitation light irradiating means 1 for irradiating the excitation light in the above-mentioned wavelength region and the fluorescence receiving means 2 for receiving the fluorescence. Regarding the reflected light, it is sufficient to receive the same light in the wavelength region of 200 to 300 nm as the excitation light.

<Embodiment 2> FIG. 4 shows an example of the device configuration in the case where the number of light receiving units is one. In this device configuration, fluorescence and reflected light emitted from the water surface W irradiated with the excitation light are received by the same light receiving unit 5, and the light is split by the beam splitter 6 in two directions of a first optical path 10a and a second optical path 10b. Separately, a fluorescent filter 7 and a reflected light filter 8 are provided in each optical path, respectively, to selectively transmit light in a predetermined wavelength region and guide the light to photoelectric conversion means 9a, 9b, where the fluorescent light and the reflected light are respectively transmitted. Measure strength. In the apparatus configuration of FIG. 1, it is difficult to measure the completely same water surface W because the light receiving portions of the fluorescent light and the reflected light are located at different positions, but by using the apparatus configuration of FIG. Of water surface W can be a measurement target.

When detecting the oil by simultaneously measuring the fluorescence and the reflected light, both measurements need to be performed on the same water surface W. When the fluorescent light receiving means 2 and the reflected light receiving means 3 are separately installed, it is difficult to completely match the target water surfaces. Therefore, the fluorescent light and reflected light emitted from the water surface W irradiated with the excitation light are once guided to the same optical path, separated into two directions by a beam splitter, and one of the light is received by the fluorescent light receiving means, and the other light is received by the reflected light receiving means , It is possible to measure the fluorescence and reflected light of the completely same water surface W.

<Embodiment 3> FIG. 5 shows an example of a device configuration in the case of using one photoelectric conversion means. In the device configuration of FIG. 4, fluorescence and reflected light are measured by separate photoelectric conversion units 9a and 9b, whereas in the device configuration of FIG. 5, fluorescence and reflected light are measured by one photoelectric conversion unit 9. In this configuration, in order to measure either the fluorescence or the reflected light, it is necessary to shut off the other.
In addition, the reflected light path shutter 12 allows only one of the light beams to pass therethrough while blocking the other light beam, and guides the light beam to the condensing unit 13 and the photoelectric conversion unit 9. Switching of the optical path shutters 11 and 12 is performed by a control signal from the light emission control measurement circuit 4,
The measurement of the fluorescence and reflected light intensity in the photoelectric conversion means 9 is performed in synchronization with the switching of the optical path shutters 11 and 12.
With this configuration, it is sufficient to provide only one photoelectric conversion unit 9, and it is possible to reduce the size and cost of the entire device.

For example, in the apparatus at the time 1, the fluorescent light receiving means 2 and the reflected light receiving means 3 both use photoelectric conversion means for converting incident light into an electric signal. This function
The reflected light is common, and both measurements can be performed by one photoelectric conversion unit. One of the lights separated in two directions by the beam splitter 6 is a fluorescent filter 7 for selectively transmitting light in a wavelength range for fluorescence measurement, and the other is a reflected light filter for selectively transmitting light in a wavelength range for reflected light measurement. 8
After passing through the filters 7 and 8, the two lights are again transmitted through the same optical path, that is, the condensing unit 13, and the common photoelectric conversion unit 9.
, Fluorescence and reflected light can be measured by one photoelectric conversion unit 9. In this case, the combined light of the fluorescent light and the reflected light is incident on the photoelectric conversion means 9. In order to separate and measure each light, the light is branched by the beam splitter 6, and then separated by the fluorescent light path shutter 11 and the reflected light path. One optical path is blocked by the shutter 12.
At this time, the optical path is alternately blocked to switch the measurement of the fluorescence and the reflected light. By performing the switching at a high speed, the measurement of the fluorescence and the reflected light of the same water surface W at almost the same time can be performed. With this configuration, since only one photoelectric conversion unit is required, reduction in size and cost can be expected.

<Embodiment 4> FIG. 6 shows an example of an apparatus configuration provided with a filter switching mechanism. In the apparatus configuration of FIG. 6, the fluorescence measurement and the reflected light measurement are alternately performed by switching the fluorescent filter 7 and the reflected light filter 8 so as to be alternately arranged on the optical path by the filter switching means 14. The switching of the filter is performed by a control signal from the light emission control and measurement circuit 4, and the measurement of the fluorescence and reflected light intensity by the photoelectric conversion unit 9 is performed in synchronization with the switching of the filters 7 and 8. Even with this configuration, it is sufficient to provide only one photoelectric conversion means 9, and the size and cost of the device can be reduced. Further, the structure of the optical path is simplified, and further downsizing can be expected.

The fluorescent light receiving means is constituted by an optical filter for selectively transmitting the fluorescence of oil and a photoelectric conversion means. The fluorescent filter 7 for measuring the fluorescence is alternately provided with the reflected light filter 8 for measuring the reflected light. By switching, fluorescence and reflected light can be measured by the same photoelectric conversion means 9 without separately providing a reflected light measurement means. Measurement of fluorescence and reflected light is performed in synchronization with the switching of the optical filters 7 and 8. Also in this case, by switching the filters at high speed, it is possible to measure the fluorescence and the reflected light of the same water surface W at almost the same time.

[0036]

As described above, according to the present invention, by combining the fluorescence measurement and the reflected light measurement, it is possible to distinguish the oil film from the solid matter while maintaining the high sensitivity of the fluorescence measurement. . Further, by measuring the light in which the fluorescence and the reflected light are introduced from one light receiving unit, it is possible to expect an improvement in accuracy. Further, by improving the structure of the optical path, miniaturization and cost reduction can be expected.

[Brief description of the drawings]

FIG. 1 is a layout view of an oil film detection device according to an embodiment of the present invention.

FIG. 2 is a graph showing a change in fluorescence intensity depending on a fluorescence wavelength when a machine oil is excited at 260 nm.

FIG. 3 shows a hexane extract of polystyrene foam at 260 nm.
6 is a graph showing a change in fluorescence intensity depending on a fluorescence wavelength when excited by.

FIG. 4 is a layout diagram illustrating an example of a device configuration when a single light receiving unit is provided.

FIG. 5 is a layout diagram showing an example of a device configuration when one photoelectric conversion unit is used.

FIG. 6 is a layout diagram illustrating an example of a device configuration when a filter switching mechanism is provided.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 excitation light irradiating means 2 fluorescent light receiving means 3 reflected light receiving means 4 light emission control and measurement circuit 5 light receiving unit 6 beam splitter 7 fluorescent filter 8 reflected light filter 9 photoelectric conversion means 9a photoelectric conversion means 9b photoelectric conversion means 10a first optical path 10b Second light path 11 Fluorescent light path shutter 12 Reflected light path shutter 13 Condenser 14 Filter switching means W Water surface M Oil film

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tadanori Moka 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu Plant, Toshiba Corporation (72) Inventor Minoru Fujisawa 1-1-1, Shibaura, Minato-ku, Tokyo Shares (72) Inventor Akira Hiramoto 1 Toshiba-cho, Fuchu-shi, Tokyo Tokyo, Japan Inside Fuchu Plant, Toshiba Corporation (72) Inventor Teruyuki Shimazaki 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Fuchu Plant, Inc. (72) Inventor Akihiko Shiroda 1 Toshiba-cho, Fuchu-shi, Tokyo F-term in Fuchu Works, Toshiba Corporation (reference) 2G043 AA04 BA15 EA01 EA15 FA05 GA04 GB18 HA09 HA11 JA02 KA03 LA01 MA01 2G059 AA05 BB04 BB20 CC12 EE02 EE07 FF06 HH03 JJ02 JJ22 JJ23 KK01 KK03 NN01

Claims (5)

[Claims] An excitation light irradiating means for irradiating the water surface with excitation light; a fluorescent light receiving means for measuring a fluorescence intensity of fluorescence emitted from the water surface; and a reflected light receiving means for measuring an intensity of reflected light reflected on the water surface. Calculating means for determining the presence or absence of an oil film from the fluorescence intensity and the reflected light intensity. 2. The oil film detecting device according to claim 1, wherein
The excitation light irradiating means irradiates excitation light having a wavelength of 200 to 300 nm, the fluorescence receiving means selectively receives light having a wavelength of 300 to 400 nm, and the reflected light receiving means has the same 200 to 300 nm as the excitation light. An oil film detecting device for selectively receiving reflected light having a wavelength of 300 nm. 3. The oil film detecting apparatus according to claim 1, wherein a beam splitter for separating light from the water surface in two directions, and one of the lights separated by the beam splitter is guided to the fluorescence receiving means. An oil film detection device comprising: a first optical path; and a second optical path for guiding the other light separated by the beam splitter to the reflected light receiving unit. 4. An excitation light irradiating means for irradiating the water surface with excitation light, a beam splitter for separating light from the water surface in two directions, and a light having a fluorescence wavelength of oil disposed on one optical path of the separated light. A fluorescent filter that selectively transmits, a fluorescent light path shutter that blocks an optical path of light transmitted through the fluorescent filter, and a light that is disposed in the other optical path of the separated light and selectively transmits light having the same wavelength as the excitation light. A reflected light filter, a reflected light path shutter that operates reciprocally to the fluorescent light path shutter and cuts off the light path of the light transmitted through the reflected light filter, and returns the light separated by the beam splitter to the same light path again. A light collecting unit for guiding, a photoelectric conversion unit for measuring the intensity of light passing through the light collecting unit, and an arithmetic unit for determining the presence or absence of an oil film from the fluorescence intensity and the reflected light intensity obtained by the photoelectric conversion unit are provided. Oil film detection device, characterized in that the. 5. An excitation light irradiating means for irradiating the water surface with excitation light, a fluorescent filter for selectively transmitting light having a fluorescence wavelength of oil emitted from the water surface, and said excitation light of reflected light reflected on said water surface. A reflected light filter that selectively transmits light of the same wavelength; a filter switching unit that selectively positions the fluorescent filter or the reflected light filter in the reflected light path; and a photoelectric switch that transmits the light transmitted through the fluorescent filter and the reflected light filter. An oil film detection device comprising: a photoelectric conversion means for converting; and an arithmetic means for determining the presence or absence of an oil film from the fluorescence intensity and the reflected light intensity obtained by the photoelectric conversion means.