KR101493645B1 - Optical dissolved oxygen sensor for safeguarding sensor membrane - Google Patents

Abstract

A sensor membrane is provided to prevent the sensor membrane from being damaged or adhered by external impacts. The sensor includes a sensor body including a first light emitting portion for generating violet and blue light, a second light emitting portion for generating red light, and a light receiving portion for receiving the fluorescent signal light, and a support frame for receiving the sensor film formed of the fluorescent dye, And a sensor cap into which the sensor film portion is inserted.

Description

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

The present invention relates to an optical dissolved oxygen measurement sensor, and more particularly, to an optical measurement sensor for protecting a sensor film made of a fluorescent dye applied to a sensor for optically measuring dissolved oxygen.

Generally, in order to measure water pollution degree, the degree of pollution is measured based on the amount of oxygen dissolved in water. Also, the biological oxygen demand is the amount of dissolved oxygen that is consumed when the microorganism that grows in water undergoes oxidation and decomposition of organic matter for a certain period under certain conditions, and is usually used to express water contamination. The method for measuring the dissolved oxygen and the biological oxygen demand includes a winkler-azide oxidation method using the oxidation property of dissolved oxygen and an electric measurement method for checking 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 measurement sensors are disclosed in U.S. Patent No. 5,039,491, U.S. Patent No. 5,098,547, U.S. Patent No. 5,681,532, and the like. 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. For example, a PtTFPP fluorescent dye has a maximum intensity of red fluorescence (650 nm) at purple light (405 nm), and the intensity ratio (I ₀ / I) of fluorescence reacting with such oxygen follows the well-known Stern-Volmer equation. There are various methods for accurately and stably measuring the intensity of fluorescence. Among them, the most commonly used methods are phase shift method using phase difference of fluorescence and phase of light irradiated to the sensor film and method of measuring fluorescence decay time by irradiating pulsed light to the sensor film, And a comparative detection method comparing with the life-time.

However, the sensor film of the conventional optical measuring sensor is very weak to the external impact, and foreign substances such as algae and water are adhered to deteriorate the function of the sensor. Specifically, a fluorescent dye film such as a platinum-porphyrin complex (PtTFPP) used as a sensor film is easily broken even when rubbed with a slight force. In particular, measuring sensors that operate in water collide with substances in the water and break easily. In addition, conventional measurement sensors can not prevent fine algae and water marks in the water from adhering to the sensor film. Accordingly, it is necessary to protect the sensor film from an external impact or foreign matter. However, the conventional optical measurement sensor is not well protected.

Disclosure of Invention Technical Problem [8] The present invention has been made in view of the above problems, and it is an object of the present invention to provide an optical dissolved oxygen measurement sensor with a sensor membrane that can prevent the sensor membrane from being damaged or adhered by an external impact.

An optical dissolved oxygen measurement sensor protected with a sensor film for solving the problems of the present invention includes a sensor body including a first light emitting portion generating purple and blue, a second light emitting portion generating red light, and a light receiving portion receiving the fluorescent signal, And a sensor frame portion including a support frame for generating the fluorescence signal light and accommodating a sensor membrane made of a fluorescent dye. And a sensor cap into which the sensor film portion is inserted.

At this time, the fluorescent dye is preferably any one of a ruthenium complex (Rudpp) or a platinum porphyrin complex (PtTFPP).

In the measurement sensor of the present invention, the sensor film portion may be sequentially accommodated in the support frame in the direction of the sensor body, the black film, the sensor film, and the light transmitting plate. A cushioning film may be disposed between the sensor film and the transparent plate. The black film may be a black silicon film. The supporting frame may have a window formed to expose the black film.

In the measurement sensor according to the preferred embodiment of the present invention, the sensor cap may be connected to a cleaning part for cleaning the sensor film part. In this case, the cleaner includes a motor for supplying power built in the sensor body, a shaft reciprocating and rotating by the motor, a bearing fixed to the shaft, and a cleaning cloth support formed on one side of the bearing . On the other hand, the cleaning cloth support base may be provided with a cleaning cloth on the surface in the direction of the sensor film portion, and the position of the cleaning cloth supporting frame may be detected by the magnetic sensor.

In the measurement sensor of the present invention, the measurement sensor may further include a temperature sensing circuit capable of sensing the temperature of the sensor film. At this time, the temperature sensing may be performed by a thermoelectric element incorporated in the optical cable into which the fluorescent signal light emitted from the sensor film is input.

According to the optical dissolved oxygen sensor of the present invention, the sensor membrane can be prevented from being damaged by an external impact by providing a support for covering the sensor membrane. In addition, by using the cleaning section that cleans the sensor film, it is possible to remove foreign matter adhering to the sensor film portion. The sensor film can be protected from external impacts and the foreign matter adhering to the sensor film can be removed at any time, so that the measurement sensor can be used for a long period of time. Furthermore, a temperature sensing circuit for correcting the temperature of the sensor film may be added to perform signal correction according to the temperature of the sensor film by the controller.

1 is a perspective view showing an optical dissolved oxygen measurement sensor in which a sensor film according to the present invention is protected.
2 is a schematic cross-sectional view for explaining a measurement sensor of the present invention including the cleaning section of FIG.
FIG. 3 is an exploded perspective view illustrating a sensor film portion inserted into the sensor cap of FIG. 1. FIG.
4 is an exploded perspective view for explaining a method of measuring dissolved oxygen using the sensor membrane according to the present invention.
5 is a block diagram illustrating a circuit in which an optical dissolved oxygen measurement sensor according to the present invention operates.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention.

The embodiment of the present invention uses a cleaning section that wraps a sensor membrane of an optical measuring sensor and further cleans the sensor membrane so that a sensor membrane that can prevent the sensor membrane from being damaged by an external impact or adhering foreign matter is protected An optical dissolved oxygen measurement sensor is presented. To this end, the optical measuring sensor of the present invention will be described in detail, and the process of protecting the sensor film of the present invention by the supporting part and the cleaning part will be described in detail. Here, the protection of the sensor film means preventing the foreign substance from adhering to the sensor film without damaging the sensor film. The measurement sensor of the present invention can be used for the measurement of dissolved oxygen in streams and lakes, the management of dissolved oxygen concentration in sewage and wastewater treatment plants, and the portable optical dissolved oxygen detector. In other words, the measurement sensor of the present invention can be used not only in water but also in air.

1 is a perspective view showing an optical dissolved oxygen measurement sensor in which a sensor film is protected according to an embodiment of the present invention.

1, the measurement sensor of the embodiment of the present invention includes a cleaner 10, a sensor film portion 20, a sensor cap 30, a sensor shell 40, a sensor body 42 and a matching connector 44 . The sensor cap 30 may be secured to the sensor body 42 by a plurality of fastening portions 34. Although not shown, the sensor shell 40 can be packaged with the cleaning portion 10 and the sensor film portion 20 while extending in the direction of the cleaning portion 10 to accommodate a portion necessary for the operation of the sensor. The sensor enclosure 40 and the sensor cap 30 may be made of various materials depending on the environment in which they are used, and stainless steels resistant to corrosion are preferred when used in water. The matching connector 44 supplies power to the circuit disposed inside the sensor body 42 and outputs the received signal.

The shapes of the sensor body 42 and the sensor cap 30 may vary depending on the portion to which the measurement sensor of the present invention is applied. For example, a rectangular parallelepiped shape can be used if a plurality of measurement sensors are bundled together, or a cylindrical shape if a single measurement sensor is used. Inside the sensor body 42, a circuit for controlling the operation of the measurement sensor and detecting and correcting the dissolved oxygen amount, and an independent power source as required are incorporated. This will be described later in detail. The matching connector 44 is connected to an auxiliary means such as a monitor and can process the information detected by the measuring sensor in accordance with the situation.

2 is a schematic cross-sectional view for explaining a measurement sensor of the present invention including the cleaning portion 10 of FIG. For convenience of explanation, the sensor body 40 is partially shown.

2, the cleaner 10 includes a motor 11 disposed inside a sensor body 42, a bearing 13 positioned outside the sensor body 42, and a motor 13 connected to the bearing 11 And a shaft 12 that reciprocates and rotates. The shaft 12 is inserted into the shaft hole 35 formed in the sensor cap 30. [ At this time, the sensor cap 30 is fixed to the sensor body 42 by a fastening part 34 composed of a fastening hole 34a and a fastening part 34b fastened by a bolt and nut method, 10). The sensor film portion 20 may be formed of a metal such as aluminum. A cleaning cloth 15 and a cleaning cloth support base 14 are attached to one side of the bearing 13. The cleaning cloth 15 may be formed of a fabric having a good cleaning effect, for example, a cloth added with a small amount of a polyacrylic resin mainly composed of 100% pure cotton.

On the other hand, when the sensor membrane portion 20 is used in water, fine algae adhere to the water film, and when the sensor membrane portion 20 is used in the air, floating dust adheres to the sensor membrane portion 20. It is possible to clean the sensor film portion 20 by rotating the cleaning portion 10 in close contact with the sensor film portion 20 by using the reciprocating motion of the motor 11. [ In other words, foreign matter such as fine algae, water mist, dust, etc. can be removed regularly or irregularly by the cleaning part 10. The sensor film made of the conventional fluorescent dye is difficult to remove the contamination of the foreign matter, and the function of the sensor is deteriorated over time.

3 is an exploded perspective view for explaining the sensor film portion 20 inserted into the sensor cap 30 of FIG. Here, the sensor cap 30 and the fastening portion 34 will be described in detail with reference to FIG.

3, the sensor cap 30 is provided with a sensor film portion insertion hole 31 into which the sensor film portion 20 is inserted, and the sensor film portion insertion hole 31 is provided with a locking protrusion 32 and a light transmitting body insertion hole 33 Is formed. The sensor film portion 20 includes a support frame 21 in which a plurality of windows 21a are opened, a black film 22 accommodated in the support frame 21, a sensor film 23, a buffer film 24, 25). The sensor film portion 20 preferably has a rectangular shape with rounded corners. This is because the consumption of the black film 22, the sensor film 23, and the buffer film 24 inserted into the support frame 21 can be reduced to the utmost when they are formed into a rectangular shape. Some conventional measurement sensors have a sensor film in a circular shape, so that a sensor film is unnecessarily consumed.

The support frame 21 has a plurality of windows 21a, and the black film 22 is exposed to the outside. The window 21a is preferably in the form of a rectangle so that the black film 22 can be exposed as much as possible and the number of the windows 21a is set in advance in consideration of the size of the support frame 21 and the stability of the sensor film portion 20. [ Can be set. The supporting frame 21 may adopt various materials depending on the environment in which it is used, and stainless steel which is resistant to corrosion is preferable when used in water. The side wall portion 21b of the support frame 21 stops at the engagement protrusion 32 of the sensor membrane insert hole 31 and can have the same profile as the surface of the sensor cap 30 or slightly protrude. The bent portion 21c is connected to the end portion of the side wall portion 21b so that the black film 22, the sensor film 23, the buffer film 24 and the translucent body 25 are embedded and fixed.

The black film 22 is provided so as not to deteriorate the sensitivity of the measurement sensor of the present invention by incoming light or the like coming from the outside. That is, the black film 22 prevents light, such as visible light incident from the outside, from being absorbed by the sensor film 23 and affecting the sensitivity of the sensor film 23. The black film 22 is preferably a polymer film in which a black pigment is mixed with a hydrophobic film and has ductility enough not to damage the sensor film 23 due to its strong rigidity. In addition, since the black film 22 prevents the sensor film 23 from directly being exposed to the outside, the sensor film 23 can be protected from external impacts or foreign substances, thereby making it possible to use the measurement sensor of the present invention for a long period of time .

The black film 22 can be variously selected within the scope of the present invention, but a silicon film or a Teflon film is more preferable. The black silicone film is more suitable for the black film 22 of the present invention because it has good gas permeability, excellent mechanical strength and excellent ability to block external light.

The sensor film 23 is a film made of a dye that emits fluorescence when receiving light, and the fluorescent dye is a metal such as a stilbene derivative, an imidazole derivative, a coumarin derivative, or the like bonded to platinum or ruthenium. As an example of the present invention, a ruthenium complex (Rudpp) and a platinum porphyrin complex (PtTFPP) were used as fluorescent dyes. The fluorescent dye emits red fluorescence in accordance with the concentration of dissolved oxygen in the sensor film 23. However, other types of fluorescent dyes can be applied within the scope of the technical idea of the present invention. The cushioning film 24 serves to buffer the stress that may occur between the sensor film 23 and the light transmitting body 25, and is preferably a transparent polymer film having high ductility so that the fluorescent light can pass therethrough. The buffer film 24 may be a thermoplastic resin film, a thermosetting resin film, for example, a polyester film, an OPP film, or the like.

The light transmitting member 25 is made of a transparent material, and any one selected from glass, PMMA, PC, PE, and PET can be used. Of these, PMMA is preferable. The translucent body 25 is constituted by a translucent plate 25a to which the fold 21c of the support frame 21 is fixed and a translucent rod 25b to be inserted into the translucent body insertion hole 33. [ In other words, the support frame 21 is fixed with the black film 22, the sensor film 23, the cushioning film 24, and the translucent plate 25a, and the translucent rod 25b is fixed to the support frame 21 It is located outside. For this purpose, a space is provided between the latching jaw 32 and the light-transming body inserting hole 33 so that the bent portion 21c can be disposed. The light projecting rod 25b has an area and a shape such that the light emitted from the light emitting portion to be described later can pass through.

4 is an exploded perspective view for explaining a method of measuring dissolved oxygen using the sensor film 23 according to the embodiment of the present invention. 5 is a block diagram illustrating a circuit in which an optical dissolved oxygen measurement sensor according to an embodiment of the present invention operates. Here, the structure of the measurement sensor will be described with reference to FIG. 1 to FIG. Also, for convenience of explanation, the sensor enclosure 40 and the sensor body 42 are only partially represented.

4 and 5, the sensor body 42 includes a first light emitting portion 50 for generating purple or blue (hereinafter referred to as purple), a second light emitting portion 52 for generating red light, and a light receiving portion 54). The first and second light emitting portions 50 and 52 are preferably LEDs and light of a purple color (about 405 nm) or red (about 650 nm) is transmitted through the light transmitting body 25 and the buffer film 24 to the sensor film 23, . When the light receiving unit 54 is formed of a photodiode, the light receiving unit 54 may be connected to a conventional optical cable (not shown) to receive signal light including fluorescence. The light receiving unit 54 outputs the red fluorescent signal light emitted from the sensor film 23 according to the concentration of dissolved oxygen as electrical energy by the optical cable. The optical cable is provided at a position where the first and second light emitting portions (50, 52) and the sensor film (23) intersect to receive the fluorescent signal light output from the sensor film (23). The light receiving unit 54 includes an OP amplifier and an amplifier and may include a color filter (650 nm to 700 nm) for separating fluorescence from the signal light on the front surface of the light receiving unit 54.

The operation of each of the first and second light emitting units 50 and 52 is performed by the first light emitting unit driving circuit 102 and the second light emitting unit driving circuit 104. The optical signal detection by the light receiving unit 54 And is performed by the optical signal detecting circuit 106. The second light emitting portion driving circuit 104 may include a correction circuit for correcting a decrease in the fluorescent light signal due to yellowing of the optical cable due to ultraviolet rays of the first light emitting portion 50. The control unit 110 appropriately controls the operations of the first and second driving circuits 102 and 104 and the optical signal detecting circuit 106. [ 2 receives the drive command for cleaning the surface of the sensor film portion 20 from the controller 110, the operation of the motor 11 is performed through the cleaning drive circuit 112. [ More specifically, when the cleaning cloth 15 is brought into close contact with a predetermined position through a magnetic sensor or the like that senses the position of the cleaning cloth 15 of the cleaning section, The reciprocating motion of the rotor 10 is stopped and rotational motion is performed as necessary.

Meanwhile, the measurement sensor according to the embodiment of the present invention may further include a temperature sensing circuit 108 capable of sensing the temperature of the sensor. This is because the fluorescence amount of the fluorescent dye varies depending on the temperature. Specifically, the temperature measured from a thermoelectric element, for example, an NTC element incorporated in the optical cable is read in the controller 110 to correct the temperature of the fluorescent dye of the sensor film 23. The controller 110 may include a filter algorithm that removes noise included in the circuit and noise included in fluorescence from the sensor film 23 in the received signal light. Further, when the user inputs the control signal, it may further include a separate algorithm capable of processing the control signal. In the figure, the UART matching circuit 116 causes the control unit 110 to process commands such as temperature correction of the user and pulse period of the purple light. The measured fluorescence value is sent to the user through the UART matching circuit 116 as a digital signal, and various commands are received from the user.

In addition, it may include an encoder 114 and other output circuit 118 for processing the data of the measurement sensor. And a user interface circuit for allowing a user to directly input the data for correcting the change in the content of water in the water and the change in oxygen concentration in the water (oxygen vapor pressure) in accordance with the change in the atmospheric pressure, which can affect the dissolved oxygen concentration.

According to the optical dissolved oxygen measurement sensor according to the embodiment of the present invention, the support for covering the sensor membrane can be provided to prevent the sensor membrane from being damaged by an external impact. In addition, by using the cleaning section that cleans the sensor film, it is possible to remove foreign matter adhering to the sensor film portion. Further, a temperature sensing circuit for correcting the temperature of the sensor film may be added, and the signal may be corrected by the controller according to the temperature of the sensor film.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the spirit and scope of the invention. It is possible.

10; The government 11; motor
12; Shaft 13; bearing
14; A cleaning cloth support 15; Cleaning cloth
20; A support 21; Support frame
22; Black film 23; Sensor membrane
24; Buffer film 25; Transparent body
30; Sensor cap 31; Sensor membrane insert hole
32; A latching jaw 33; Transparent body insertion hole
34; Fastening portion 40; Sensor sheath
42; A sensor body 44; Matching connector
50; A first light emitting portion 52; The second light-
54; A light receiving unit 102; The first light-
104; A second light emitting portion drive circuit 106; The optical signal detection circuit
108; Temperature sensing circuit 110; The control unit
112; A taxi drive circuit 116; URT matching circuit

Claims (12)

A sensor body including a first light emitting portion generating violet and blue, a second light emitting portion generating red light, and a light receiving portion receiving the fluorescent signal light;
A sensor film portion which generates the fluorescent signal light and accommodates a sensor film made of a fluorescent dye and includes a support frame in which a black film, a sensor film, a buffer film, and a transparent plate are sequentially received in the sensor body direction;
A sensor cap into which the sensor film portion is inserted; And
And a temperature sensing circuit for sensing the temperature of the sensor film and correcting the temperature of the fluorescent dye by a control unit,
Wherein the buffer film passes the fluorescence signal light and buffers stress between the sensor film and the transparent plate, wherein the sensor film is protected. The sensor according to claim 1, wherein the fluorescent dye is any one of a ruthenium complex (Rudpp) or a platinum porphyrin complex (PtTFPP). delete delete The sensor membrane protected optical dissolved oxygen measurement sensor according to claim 1, wherein the black film is a black silicon film. [2] The sensor according to claim 1, wherein the supporting frame has a window for exposing the black film. 2. The sensor according to claim 1, wherein the sensor cap is connected to a cleaning part for cleaning the sensor film part. 8. The apparatus of claim 7,
A motor for supplying power to the sensor body;
A shaft reciprocating and rotating by the motor;
A bearing fixed to the shaft; And
And a cleansing foil support base formed on one side of the bearing. The sensor according to claim 8, wherein a cleaning cloth is attached to a surface of the cleaning cloth supporting base in the direction of the sensor film. The sensor membrane protected optical dissolved oxygen measurement sensor according to claim 8, wherein the position of the cleaning cloth support is sensed by a magnetic sensor. delete The sensor according to claim 1, wherein the temperature sensing is performed by a thermoelectric element incorporated in an optical cable into which the fluorescent signal light emitted from the sensor film is input.

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