Fluorescence method dissolved oxygen sensor

Abstract

The utility model discloses a fluorescence method dissolved oxygen sensor which comprises a shell, an LED support and a lens support, and a circuit board and a photoelectric receiving tube located at the lower end of the circuit board are arranged in the shell. The LED support is fixed in the shell, two excitation light sources are fixed on the LED support, and a collimating lens fixed with the LED support is arranged at the light emitting position of each excitation light source. The lens support is arranged in the LED support in a penetrating mode, part of the photoelectric receiving tube is inserted into the lens support, and a lens and an optical filter which are sequentially arranged below the photoelectric receiving tube are fixed in the lens support. The dissolved oxygen sensor optimizes an optical system and improves the detection precision.

Description

TECHNICAL FIELD

[0001] The utility model relates to water quality detection equipment technical field especially relates to a fluorescence method dissolved oxygen sensor. BACKGROUND

[0002] Dissolved oxygen sensor is generally divided into two types of electrochemical method and fluorescence method according to the different measurement principles.

[0003] Electrochemical method includes polarographic method and primary cell method, wherein the electrode of polarographic method dissolved oxygen sensor needs a certain time polarization, after using for a period of time, the anode will form silver oxide layer, and the electrode service life is limited, and the probe needs to be cleaned and replaced frequently. And primary cell method dissolved oxygen sensor is susceptible to the influence of hydrogen sulfide in water, thereby interfering with the measurement accuracy, and the electrode service life is limited, and the probe needs to be cleaned and replaced frequently. And fluorescence method dissolved oxygen sensor is based on fluorescence quenching effect, and the fluorescence material emits fluorescence when being excited by light of a specific wavelength, and dissolved oxygen and fluorescence material occur oxidation-reduction reaction, resulting in the weakening of fluorescence intensity or the shortening of fluorescence lifetime, and the dissolved oxygen content is indirectly calculated by detecting the change of fluorescence intensity or fluorescence lifetime, and is widely applied in water quality detection. But the existing fluorescence method dissolved oxygen sensor is insufficient in optical system design, and the scattered light generated by excitation light source influences the measurement accuracy. SUMMARY

[0004] In order to overcome the above-mentioned shortcomings, the purpose of the utility model is to provide a fluorescence method dissolved oxygen sensor, which optimizes the optical system and improves the detection accuracy.

[0005] In order to achieve the above purpose, the utility model adopts the technical scheme of a fluorescence method dissolved oxygen sensor, which comprises:

[0006] A shell is provided with a circuit board and a photoelectric receiving tube at the lower end of the circuit board;

[0007] An LED support is fixed in the shell, and two excitation light sources are fixed on the LED support, and a collimating lens fixed with the LED support is arranged at the light outlet of each excitation light source;

[0008] A lens support is arranged in the LED support, part of the photoelectric receiving tube is inserted into the lens support, and a lens and a filter are sequentially arranged below the photoelectric receiving tube and fixed in the lens support.

[0009] The utility model has the advantages that corresponding collimating lenses are added at the excitation light sources, the scattered light generated by the excitation light sources is reduced, the scattered light emitted by the excitation light sources becomes parallel light after passing through the collimating lenses, and can uniformly irradiate the fluorescence film, thereby improving the measurement accuracy.

[0010] Further, the two excitation light sources are a red LED and a blue LED respectively, the light emitting direction of the excitation light source forms an angle with the axis of the lens holder, the collimating lens is perpendicular to the light emitting direction of the excitation light source, so that the scattered light emitted by the excitation light source becomes parallel light.

[0011] Further, the shell comprises an upper shell and a lower shell fixed at the bottom of the upper shell, the LED holder is compressed between the upper shell and the lower shell, a limiting groove is formed between the upper shell and the lower shell, and the LED holder comprises a plug-in boss inserted into the limiting groove.

[0012] Further, the lower shell is provided with a fluorescent film below the LED holder.

[0013] Further, the LED holder is fixedly connected with the circuit board through a locking member, the locking member is a locking bolt fixedly connected with the circuit board, and the wiring end of the excitation light source is welded with the circuit board.

[0014] Further, the LED holder is provided with a slot, part of the lens holder is inserted into the slot, the bottom of the slot is provided with a limiting boss abutting against the lens holder, and the circuit board abuts against the upper end of the lens holder to compress the lens holder on the limiting boss.

[0015] The LED holder provided with the collimating lens is first fixed with the lens holder, then the LED holder is fixed with the circuit board provided with the excitation light source, and finally fixed into the shell.

[0016] Further, the circuit board is fixed with a temperature sensor, because the water temperature also affects the dissolved oxygen concentration, temperature compensation is performed in combination with the temperature collected by the temperature sensor, and therefore the calculated dissolved oxygen concentration in the water quality is more accurate.

[0017] Further, the upper shell and the lower shell are screw-connected, facilitating assembly. DETAILED DESCRIPTION

[0018] Figure 1 is a sectional view of the embodiment of the utility model;

[0019] Figure 2 is Figure 1 is an enlarged view of A in figure 2;

[0020] Figure 3 is a schematic view of the connection of the LED holder, the circuit board and the lens holder in the embodiment of the utility model;

[0021] Figure 4 is a schematic view of the lens holder structure in the embodiment of the utility model.

[0022] In the drawings:

[0023] 1, housing; 11, upper shell; 12, lower shell; 13, fluorescent film;

[0024] 2, circuit board; 21, temperature sensor;

[0025] 3, LED support; 31, slot; 32, plug boss; 33, connecting part;

[0026] 4, excitation light source;

[0027] 5, collimating lens;

[0028] 6, lens support;

[0029] 71, lens; 72, filter. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application.

[0031] It should be noted that in the description of the present application, the terms "upper", "lower", "left", "right", "front", "back" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings, which is only for the convenience of description, and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0032] In addition, it should also be noted that in the description of the present application, unless otherwise explicitly specified and limited, the terms "provided", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] A fluorescent method dissolved oxygen sensor of the present application, as shown in the accompanying Figure 1 and the accompanying Figure 2 It comprises a housing 1, an LED support 3 and a lens support 6.

[0034] The shell 1 is provided with a circuit board 2 and a photoelectric receiving tube at the lower end of the circuit board 2, the photoelectric receiving tube is welded and fixed on the circuit board 2 and is in communication connection with the circuit board 2, the circuit board 2 is used for signal processing and control of exciting light sources 4. The LED support 3 is fixed in the shell 1, two exciting light sources 4 are fixed on the LED support 3. The lens support 6 is arranged in the LED support 3, part of the photoelectric receiving tube is inserted into the lens support 6, and a lens 71 and a filter 72 are fixed in the lens support 6 in sequence below the photoelectric receiving tube.

[0035] In the embodiment, the single-chip microcomputer module above the circuit board 2 controls two exciting light sources 4 to respectively emit a beam of light source with a specific wavelength in the form of a high-frequency square wave, irradiates on the fluorescent film 13 on the shell 1, passes through the filter 72 and the lens 71 after reflection, and irradiates on the photoelectric receiving tube, so that the photoelectric signal is recorded by the phase detection module on the circuit board 2, and the detection is completed.

[0036] In one embodiment, referring to FIG. 1, Figure 2 As shown in the figure, a collimating lens 5 fixed with the LED support 3 is arranged at the light-emitting position of each exciting light source 4, and the collimating lens 5 can optimize the light rays of the exciting light source 4. The collimating lens 5 and the LED support 3 are assembled in advance to form a fixed part.

[0037] In the embodiment, corresponding collimating lenses 5 are added at the exciting light sources 4, so that the scattered light generated by the exciting light sources 4 is reduced, the scattered light rays emitted by the exciting light sources 4 become parallel light after passing through the collimating lenses 5, and the fluorescent film 13 can be uniformly irradiated, thereby improving the measurement accuracy.

[0038] The two exciting light sources 4 are red LEDs and blue LEDs respectively, the light-emitting direction of the exciting light source 4 forms an angle with the axis of the lens support 6. The collimating lens 5 is perpendicular to the light-emitting direction of the exciting light source 4, so that the scattered light rays emitted by the exciting light source 4 become parallel light, and the light rays emitted by the exciting light source 4 can irradiate more on the surface of the fluorescent film 13.

[0039] The blue light emitted by the blue LED passes through the corresponding collimating lens 5 light source optimization and irradiates on the fluorescent film 13. The fluorescent substance in the fluorescent film 13 is excited after absorbing light energy and generates fluorescence. The dissolved oxygen in water penetrates the fluorescent film 13 and contacts the fluorescent substance, generates fluorescence quenching effect, and causes the fluorescence intensity to weaken or the fluorescence lifetime to shorten. The quenched fluorescence passes through the filter 72 and the lens 71 after reflection and irradiates on the photoelectric receiving tube, and the photoelectric signal is recorded by the phase detection module. The red light emitted by the red LED has the same principle, and the relationship curve of different dissolved oxygen concentrations is established through the phase difference of two phases, so as to calculate the dissolved oxygen concentration in the water quality.

[0040] Because water temperature also affects dissolved oxygen concentration, in one embodiment, see Appendix Figure 3 As shown, a temperature sensor 21 is fixed on the circuit board 2. The temperature sensor 21 is used to detect the temperature of the entire dissolved oxygen sensor, which is approximately the temperature of the water body. Temperature compensation is performed by combining the temperature collected by the temperature sensor 21, and the dissolved oxygen concentration in the water is calculated more accurately at this time.

[0041] See appendix Figure 1 and attached Figure 2 As shown, the housing 1 includes an upper shell 11 and a lower shell 12 fixed to the bottom of the upper shell 11. The upper shell 11 and the lower shell 12 are threaded together, and a sealing ring is provided between them to improve the sealing performance of the connection. The LED bracket 3 is pressed between the upper shell 11 and the lower shell 12. At this time, the LED bracket 3 does not require additional fasteners and is directly fixed to the housing 1. When the upper shell 11 and the lower shell 12 are mated, a limiting groove is formed between them. The LED bracket 3 includes an insertion boss 32 that inserts into the limiting groove.

[0042] A fluorescent film 13 is provided on the lower shell 12, located below the LED bracket 3.

[0043] In one embodiment, the LED bracket 3 is fixedly connected to the circuit board 2 by a locking member, see Appendix Figure 4 As shown, the LED bracket 3 includes a connecting part 33, which abuts against the side of the circuit board 2. The locking component is a locking bolt that fixes the connecting part 33 and the circuit board 2. The terminals of the excitation light source 4 are soldered to the circuit board 2, and the circuit board 2 controls the excitation light source 4 to emit light.

[0044] The LED bracket 3 has a slot 31, and part of the lens bracket 6 is inserted into the slot 31. The bottom of the slot 31 is provided with a limiting boss that abuts against the lens bracket 6. The limiting boss is used to limit the position of the lens bracket 6. The circuit board 2 abuts against the upper end of the lens bracket 6 to press the lens bracket 6 tightly against the limiting boss.

[0045] At this point, the LED bracket 3 equipped with the collimating lens 5 is first fixed to the lens bracket 6, then the LED bracket 3 is fixed to the circuit board 2 equipped with the excitation light source 4, and finally fixed into the housing 1.

[0046] Circuit board 2 can be connected to an external controller wirelessly or via cable, and transmits the acquired signals to the controller wirelessly or via cable. In this embodiment, because a collimating lens 5 is added at the excitation source 4, the scattered light generated by the excitation source 4 is reduced and made into parallel light, thus improving the measurement accuracy. At the same time, a high-precision temperature sensor 21 is added for real-time temperature compensation, reducing the impact of temperature on fluorescence intensity or fluorescence lifetime.

[0047] The above embodiments only illustrate the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A fluorescence-based dissolved oxygen sensor, characterized in that: include: A housing, wherein a circuit board and a photoelectric receiver tube located at the lower end of the circuit board are disposed inside the housing; An LED bracket is fixed inside the housing. Two excitation light sources are fixed on the LED bracket, and a collimating lens fixed to the LED bracket is provided at the light emission point of each excitation light source. A lens holder is inserted into the LED holder, and a portion of the photoelectric receiving tube is inserted into the lens holder. A lens and a filter are fixed inside the lens holder and arranged sequentially below the photoelectric receiving tube.

2. The fluorescence dissolved oxygen sensor according to claim 1, characterized in that: The two excitation light sources are a red LED and a blue LED, respectively. The light emission direction of the excitation light source forms an angle with the axis of the lens bracket, and the collimating lens is perpendicular to the light emission direction of the excitation light source.

3. The fluorescence dissolved oxygen sensor according to claim 1, characterized in that: The housing includes an upper shell and a lower shell fixed to the bottom of the upper shell. The LED bracket is pressed between the upper shell and the lower shell, and a limiting groove is formed between the upper shell and the lower shell. The LED bracket includes a plug-in boss that is inserted into the limiting groove.

4. The fluorescence dissolved oxygen sensor according to claim 3, characterized in that: A fluorescent film is provided on the lower shell below the LED bracket.

5. The fluorescence dissolved oxygen sensor according to claim 1, characterized in that: The LED bracket is fixedly connected to the circuit board by a locking device, and the terminals of the excitation light source are soldered to the circuit board.

6. The fluorescence dissolved oxygen sensor according to claim 1, characterized in that: The LED bracket has a slot, a portion of the lens bracket is inserted into the slot, and a limiting boss is provided at the bottom of the slot to abut against the lens bracket. The circuit board abuts against the upper end of the lens bracket to press the lens bracket tightly against the limiting boss.

7. The fluorescence dissolved oxygen sensor according to any one of claims 1-6, characterized in that: A temperature sensor is fixed on the circuit board.

8. The fluorescence dissolved oxygen sensor according to claim 3, characterized in that: The upper shell and the lower shell are threaded together.

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