KR20160093771A - optical dissolved oxygen sensor - Google Patents

Abstract

The present invention relates to an optical sensor device to detect dissolved oxygen. The optical sensor device to detect dissolved oxygen comprises: a first light source installed in a housing to emit light of 460-480 nm towards the outside of the housing; a second light source installed in the housing to emit light of 600-620 nm towards the outside of the housing; a sensor film made of fluorescent dye excited by the light emitted by the first light source, and mounted on the housing to allow one side thereof to be exposed to the outside of the housing corresponding to light emission paths of the first and the second light source; a light detector installed to face the sensor film to detect the light of 600-620 nm received from the sensor film; and a control unit to control drive of the first and the second light source, and measure dissolved oxygen of water coming in contact therewith through the sensor film from a signal received from the light detector. The control unit performs a calibration mode to drive the second light source to determine whether the signal received from the light detector corresponds to a prescribed normal range to determine whether the sensor film is normal, and a measurement mode to drive the first light source to measure dissolved oxygen from the signal received from the light detector. According to the optical sensor device to detect dissolved oxygen, a state of the sensor film is diagnosed to reduce a measurement error.

Description

[0001] The present invention relates to an optical dissolved oxygen sensor,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sensor device for detecting dissolved oxygen, and more particularly, to an optical sensor device for dissolved oxygen detection capable of diagnosing a state of a sensor film to reduce measurement errors.

In general, there is a method for measuring the amount of oxygen dissolved in water, that is, dissolved oxygen, as a method for measuring the degree of contamination of water.

In addition, the biological oxygen demand is the amount of dissolved oxygen consumed by the microorganism that grows in the water when the organic matter is oxidized and decomposed for a certain period under a certain condition, and is usually used to express the degree of contamination of water. Methods for measuring dissolved oxygen and biological oxygen demand include the winkler-azide method using dissolved oxygen's oxidizing properties, and an electrical measurement method to determine the diffusion rate of oxygen across the electrode membrane. Although the Winkler-Azide conversion method is widely used, measurement and measurement methods using optical measuring instruments are now preferred because of quick and easy use of the reagent because the preparation and titration of the reagents are troublesome and difficult.

Optical measuring sensors are variously disclosed in U.S. Patent No. 5,039,491.

Fluorescence spectroscopy using fluorescent dyes among optical measurement sensors has been developed in various forms and methods. At this time, a ruthenium complex (Rudpp) and a platinum porphyrin complex (PtTFPP) are generally used as fluorescent dyes.

In the case of the optical measuring method using the sensor film made of such a fluorescent dye, foreign substances such as algae and water are adhered to deteriorate the function of the sensor, and a structure capable of suppressing such measurement errors is required.

It is an object of the present invention to provide an optical sensor device for dissolved oxygen detection, which is developed to solve the above-mentioned problems, and which can reduce the measurement error by diagnosing the performance of the sensor membrane.

According to an aspect of the present invention, there is provided an optical sensor device for detecting dissolved oxygen, comprising: a housing; A first light source installed in the housing and emitting light of 460 to 480 nm in a direction toward the outside of the housing; A second light source installed in the housing and emitting light having a wavelength of 600 to 620 nm toward the outside of the housing; A sensor film formed of a fluorescent dye that is excited by light emitted from the first light source and mounted on the housing so as to expose one side to the outside of the housing corresponding to a light emission path of the first and second light sources; A photodetector disposed opposite to the sensor film and detecting 600 to 620 nm light received from the sensor film; And a control unit for controlling the driving of the first and second light sources and measuring the dissolved oxygen of water in contact with the sensor film from the signal received from the photodetector, A calibration mode for driving the second light source to determine whether a signal received from the photodetector corresponds to a set normal range; and a controller for driving the first light source to measure dissolved oxygen from a signal received from the photodetector As shown in FIG.

Preferably, the control unit further comprises a cleaning unit capable of mechanically cleaning the sensor film, and the control unit drives the second light source in the calibration mode to judge that the signal received from the photodetector is out of the set normal range It is structured so as to operate the taxing section.

The control unit drives the second light source when the calibration mode is performed and if the signal received from the photodetector is determined to be out of the set normal range, the control unit drives the first light source in the measurement mode, And the dissolved oxygen is calculated by reflecting the correction value for the signal.

According to the optical sensor device for detecting dissolved oxygen according to the present invention, it is possible to diagnose the state of the sensor film and to reduce measurement errors.

1 is a cross-sectional view showing an optical sensor device for detecting dissolved oxygen according to the present invention,
2 is a block diagram showing the control system of the optical sensor device for dissolved oxygen detection of FIG.

Hereinafter, an optical sensor device for detecting dissolved oxygen according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an optical sensor device for detecting dissolved oxygen according to the present invention, and FIG. 2 is a block diagram showing a control system of the optical sensor device for detecting dissolved oxygen according to FIG.

1 and 2, an optical sensor device 100 for detecting dissolved oxygen according to the present invention includes a housing 110, first and second light sources 121 and 122, a sensor film 140, (150).

The first light source 121 emits light of 460 to 480 nm toward the front of the housing 110 in which the sensor film 140 is mounted.

The first light source 121 may be a light emitting diode that emits light of 470 nm.

The second light source 122 is installed in the housing 110 to emit light having a wavelength of 600 to 620 nm toward the front surface of the housing 140 in which the sensor film 140 is mounted.

And the second light source 122 emits light of 610 nm.

Since the second light source 122 does not excite the sensor film 140, which will be described later, the second light source 122 can be used to grasp the state of transmissivity conversion due to damage of the foreign substance or the film quality of the sensor film 140.

The sensor film 140 is formed of a fluorescent dye that is excited by the light emitted from the first light source 121 and corresponds to the light output path of the first and second light sources 121 and 122, Is mounted on the front surface of the housing 110 so as to be exposed.

The sensor film 140 is a film made of a fluorescent dye that emits fluorescence when it receives light. The fluorescent dye is a metal such as a stilbene derivative, an imidazole derivative, or a coumarin derivative bonded to a metal such as platinum or ruthenium.

The ruthenium complex (Rudpp) and the platinum phophillin complex (PtTFPP) may be applied as the fluorescent dye to the sensor film 140, and the ruthenium complex is used in this embodiment.

When the first light source 121 emits light of 470 n, the sensor film 140 emits red fluorescence of 600 to 620 nm according to the concentration of dissolved oxygen in the water to which the sensor film 140 is exposed.

The photodetector 130 is disposed opposite to the sensor film 140 to detect the light of 600 to 620 nm received from the sensor film 140. Reference numeral 131 denotes a filter which is provided at the front end of the photodetector 130 and which transmits only light in the 600 to 620 nm band.

The cleaning part is capable of mechanically cleaning the foreign substance adhering to the sensor film 140. [

The cleaning section includes a motor (M) 165 and a brush 167 for mechanically cleaning the sensor film 140 while being rotated by driving of the motor 165.

The control unit 150 controls the driving of the first and second light sources 121 and 122 and measures the dissolved oxygen of the water that is contacted through the sensor film 140 from the signal received from the photodetector 130. [

The control unit 150 includes a control unit 151, a storage unit 153, an interface unit 157, an operation unit 155, and a motor driving unit 161.

The storage unit 153 stores a normal range value for determining a normal range in the calibration mode, a first lookup table for calculating dissolved oxygen in a measurement mode when the calibration range corresponds to a normal range through a calibration process, And a second look-up table for calculating dissolved oxygen in the measurement mode when it is out of the normal range.

The controller 151 controls the second light source 122 to determine whether the sensor film 140 is abnormal and determines whether the signal received from the photodetector 130 corresponds to a predetermined normal range. One light source is driven to perform a measurement mode for measuring dissolved oxygen from the signal received from the photodetector 130.

The calibration mode may be constructed so as to be performed every set period or when the calibration mode execution setting signal is received from the operation unit 155.

The control unit 151 drives the second light source 122 in the calibration mode to compare the signal received from the photodetector 130 with the normal range value recorded in the storage unit 153. If the comparison result indicates that the signal is within the normal range Then, dissolved oxygen is calculated based on the first lookup table recorded in the storage unit 153 in the measurement mode.

Alternatively, when the control unit 151 determines that the signal received from the photodetector 130 is out of the predetermined normal range when the calibration mode is performed, the control unit 151 determines the abnormality of the sensor film 140 first, The controller 160 controls the motor 161 to rotate the sensor film 140 by the rotation of the motor 165 and then drives the second light source 122 again to determine whether the signal of the normal range set through the photodetector 130 is received And performs a judgment process. The calibration process for determining the cleaning and normal range reception is repeated a predetermined number of times. If the calibration range is out of the normal range after the predetermined number of times, the correction value is reflected in the signal detected by the photodetector 130 in the measurement mode, .

That is, as described above, the control unit 151 drives the second light source in the calibration mode, and if the signal received from the photodetector 130 is determined to be out of the set normal range, The dissolved oxygen in the subsequent measurement mode is calculated using the second look-up table of the recorded storage unit 153. [

Alternatively, when the calibration mode is performed, when the calibration mode is performed, an error message may be displayed to notify the user of the error message.

The interface unit 157 is configured to transmit the calculated dissolved oxygen to an output device, for example, an indicator or a server, and it is of course possible to construct the calculated value to be directly displayed through the display unit, unlike the illustrated example.

According to the optical sensor device 100 for detecting dissolved oxygen described above, it is possible to diagnose the state of the sensor film 140 and to reduce measurement errors.

110: housing 121: first light source
122: second light source 140: sensor film
150: control unit

Claims (3)

A housing;
A first light source installed in the housing and emitting light of 460 to 480 nm in a direction toward the outside of the housing;
A second light source installed in the housing and emitting light having a wavelength of 600 to 620 nm toward the outside of the housing;
A sensor film formed of a fluorescent dye that is excited by light emitted from the first light source and mounted on the housing so as to expose one side to the outside of the housing corresponding to a light emission path of the first and second light sources;
A photodetector disposed opposite to the sensor film and detecting 600 to 620 nm light received from the sensor film;
And a control unit for controlling the driving of the first and second light sources and for measuring dissolved oxygen in the water coming in contact with the sensor film from the signal received from the photodetector,
Wherein the control unit controls the first light source to drive the second light source to determine whether the signal received from the photodetector falls within a predetermined normal range to determine whether the sensor film is abnormal, And to perform a measurement mode for measuring dissolved oxygen from the signal received from the detector. The apparatus according to claim 1, further comprising a cleaning unit capable of mechanically cleaning the sensor film, wherein the control unit drives the second light source when the calibration mode is performed so that the signal received from the photodetector is in a set normal range And the cleaning unit is operated when it is judged that the sensor is off. The apparatus of claim 1, wherein the control unit drives the second light source when performing the calibration mode and drives the first light source in the measurement mode if the signal received from the photodetector is determined to be out of a set normal range, And the dissolved oxygen is calculated by reflecting the correction value on the signal received from the photodetector.

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