A dual-channel orthogonal phase-locked dissolved oxygen sensor device, system and method

Abstract

The present invention provides a dual-channel orthogonal phase-locked dissolved oxygen sensor device, system and method, wherein a fluorescent sensing film is installed at the first end of the device body; a fluorescent sensing film assembly is arranged near the fluorescent sensing film; a temperature sensor and an internal circuit main board are also installed on the device body; an excitation light source, a reference light source, a filter, a photodetector and a signal processing assembly are arranged on the internal circuit main board; the signal processing assembly is used to control the excitation light source to emit light, and the fluorescence signal and the reference light signal generated by the excitation are detected by the photodetector and converted into an electrical signal, the electrical signal is processed and phase-locked amplified to obtain phase information, the phase information and the temperature detection information are quantitatively analyzed, and the dissolved oxygen concentration data is calculated. The device comprehensively uses optical and electrical principles, greatly improves the signal-to-noise ratio of weak signals in circuit processing, has a short response time, high sensitivity, high precision, stable communication data, and can be remotely monitored online in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of dissolved oxygen sensors, and in particular to a dual-channel orthogonal phase-locked dissolved oxygen sensing device based on fluorescence method, a sensing system and a sensing method. Background Art

[0002] With the rapid development of industrialization, a large amount of pollutants are generated every day. Industrial wastewater and farmland irrigation water are often discharged into rivers, lakes and seas before they meet the discharge standards, causing huge pollution to various water bodies. In addition, the exhaust gas from industrial production is discharged into the atmosphere, which will indirectly lead to water pollution and aggravate the problem of water resource pollution. Therefore, it is very important to monitor and treat water quality in a timely and effective manner.

[0003] Dissolved oxygen is a very important routine parameter in water quality monitoring. Whether it is water quality monitoring in rivers, lakes, and seas or water quality monitoring in marine ranches in large-scale aquaculture industries, it is necessary to accurately monitor and measure dissolved oxygen values.

[0004] The mainstream electrode and spectrophotometric methods for testing dissolved oxygen in industrial applications currently have disadvantages such as insufficient sampling, inability to conduct long-term real-time detection, low accuracy, long response time, poor stability, and poor operability. Summary of the invention

[0005] The present invention provides a dual-channel orthogonal phase-locked dissolved oxygen sensor device based on fluorescence method. The sensor device can reduce light environment interference and reduce interference and scattering of stray light, can largely ensure the consistency of light intensity of each device, and improve the precision and accuracy of measurement.

[0006] Specifically comprising: a device body, a fluorescent sensing film is installed at the first end of the device body, and a four-wire twisted pair connector is installed at the second end of the device body; a fluorescent sensing film assembly is arranged near the fluorescent sensing film; a temperature sensor and an internal circuit mainboard are also installed on the device body;

[0007] The internal circuit main board is provided with an excitation light source, a reference light source, an optical filter, a photodetector and a signal processing component;

[0008] The filter is arranged at the rear end of the fluorescence sensing film, and the photodetector is arranged at the rear end of the filter; the temperature sensor is arranged between the filter and the fluorescence sensing film;

[0009] The excitation light source and the reference light source are installed at the first end of the device body, and the excitation light source and the reference light source are respectively in the same horizontal plane as the photodetector; the excitation light source irradiates the fluorescent sensing film, so that the wavelength of the red light emitted by the excited fluorescent sensing film and the wavelength of the red light excited by the reference light source are within a preset range;

[0010] The signal processing component is used to control the emission of the excitation light source. The fluorescence signal and reference light signal generated by the excitation are detected by the photodetector and converted into electrical signals. The electrical signals are processed and phase-locked amplified to obtain phase information. The phase information and temperature detection information are quantitatively analyzed to calculate the dissolved oxygen concentration data.

[0011] It should be further explained that a power module for supplying power to the electrical components inside the device is installed inside the device body;

[0012] The signal processing components include: I / V conversion module, signal amplification filter, dual-channel orthogonal phase-locked module, AD converter, MCU module, power management module, communication module and temperature compensation module of temperature sensor;

[0013] The photodetector is connected to the MCU module through the I / V conversion module, the signal amplification filter, the dual-channel orthogonal phase-locked module and the AD converter in sequence;

[0014] The MCU module controls the blue light LED to emit light, which generates a fluorescent signal. The blue light signal is delayed by 90° and then excites the red light LED to operate.

[0015] The MCU module is connected to the excitation light source and the reference light source respectively to control the operation of the excitation light source and the reference light source respectively;

[0016] The temperature sensor is connected to the MCU module through an AD converter; the MCU module is connected to the host computer through a communication module, and the calculated dissolved oxygen concentration data is uploaded to the host computer;

[0017] The temperature compensation module of the temperature measuring sensor is connected to the MCU module to provide a temperature compensation coefficient to the MCU module.

[0018] It should be further explained that the film layer of the fluorescent sensing film is a platinum porphyrin complex coated with an oxygen-sensitive fluorescent material.

[0019] It should be further explained that the excitation light source is an excitation blue light LED light source, and the reference light source is an excitation red light LED light source.

[0020] It should be further explained that an outer protective shell is arranged outside the device body, and the outer protective shell is made of POM material with a waterproof grade of IP68.

[0021] It should be further explained that the four-wire twisted pair connector is connected with a data transmission line and a power line.

[0022] It should be further explained that the filter is selected for light with a central wavelength of 610nm, the filter bandpass is 25nm, and the wavelength range is between 595nm and 645nm;

[0023] The temperature sensor uses metal platinum resistor PT100;

[0024] The four-wire twisted-pair connector uses a vulcanized sealed waterproof aviation plug.

[0025] The present invention also provides a dual-channel orthogonal phase-locked dissolved oxygen sensing system, comprising: a plurality of dual-channel orthogonal phase-locked dissolved oxygen sensing devices and a host computer;

[0026] The signal processing components of each dual-channel orthogonal phase-locked dissolved oxygen sensor device are respectively connected to the host computer for communication, and the calculated dissolved oxygen concentration data is uploaded to the host computer.

[0027] The present invention also provides a dual-channel orthogonal phase-locked dissolved oxygen sensing method based on fluorescence method, the method comprising:

[0028] When the device is powered on, the signal processing component controls the operation of the excitation light source and the reference light source respectively;

[0029] The excitation light source emits light, and the fluorescence signal and reference light signal generated by the excitation are detected by the photodetector and converted into electrical signals;

[0030] The signal processing component processes the electrical signal and performs phase-locked amplification to obtain phase information, quantitatively analyzes the phase information and temperature detection information, and calculates the dissolved oxygen concentration data;

[0031] The signal processing component sends the analyzed dissolved oxygen concentration data to the host computer through the communication module;

[0032] The host computer transmits data with the dual-channel orthogonal phase-locked dissolved oxygen sensor device through a communication protocol to display and store the dissolved oxygen concentration data.

[0033] It should be further explained that the method also includes:

[0034] The MCU module controls the operation of the excitation light source and the reference light source respectively;

[0035] The excitation light source generates an excitation light signal and irradiates the fluorescence sensing film, so that the wavelength of the red light emitted by the excited fluorescence sensing film and the wavelength of the red light excited by the reference light source are within a preset range;

[0036] The photodetector detects and receives the fluorescence signal and converts the fluorescence signal into an electrical signal;

[0037] The signal processing component converts the current signal into a voltage signal, and the signal amplification filter amplifies and filters the voltage signal;

[0038] The signal processing component modulates the excitation light and uses it as a reference signal for the phase-locked amplifier; the reference signal is adjusted to have the same frequency as the measured signal, and the phase information lags by 90°, so that the reference signal is correlated with the measured signal;

[0039] The signal processing component uses the reference signal to perform phase-sensitive detection on the fluorescence signal, obtains the intensity and phase information of the fluorescence signal, collects the phase information of the fluorescence signal and calculates the dissolved oxygen content;

[0040] The signal processing component processes the relationship between the phase difference and the dissolved oxygen concentration, and realizes the dissolved oxygen measurement in combination with the temperature compensation coefficient.

[0041] It can be seen from the above technical solutions that the present invention has the following advantages:

[0042] The dual-channel orthogonal phase-locked dissolved oxygen sensor device involved in the present invention comprehensively uses optical and electrical principles, greatly improves the signal-to-noise ratio of weak small signals in circuit processing, has a short response time, high sensitivity, high accuracy, stable communication data, and can be remotely monitored online in real time.

[0043] The dual-channel orthogonal phase-locked dissolved oxygen sensor device involved in the present invention has a constant current source of LED, a light guide column is placed on the excitation light source, and a special shielding material cover is used on the excitation light source and the photodetector receiving part, which greatly reduces the interference of the light environment and reduces the interference and scattering of stray light, can largely ensure the consistency of the light intensity of each device, and improve the precision and accuracy of measurement.

[0044] The present invention adopts phase-locked technology and dual-channel orthogonality, which can effectively detect the required fluorescence from a large number of light signals, and accurately obtain the phase difference information between the fluorescence and the reference light through phase-locked orthogonality. It solves the problem that it is difficult to detect weak fluorescence signals under the interference of strong background light in the marine ranch.

[0045] The I / V conversion module, signal amplification filter and dual-channel orthogonal phase-locked module of the present invention adopt an operational amplifier with dual input channels, one input channel is used as the input of the operational amplifier, and the other input channel adopts a voltage follower mode to reduce voltage jitter and greatly improve the stability of the output voltage.

[0046] A high-transmittance glass lens is added between the fluorescent sensing film and the photodetector, and then a narrow-band filter is added to the receiving window of the photodetector to greatly filter out the passage and interference of unnecessary light. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0048] Figure 1 It is a schematic diagram of a dual-channel orthogonal phase-locked dissolved oxygen sensor device;

[0049] Figure 2 It is the internal schematic diagram of the dual-channel orthogonal phase-locked dissolved oxygen sensor device;

[0050] Figure 3 It is a schematic diagram of an embodiment of a dual-channel orthogonal phase-locked dissolved oxygen sensor device;

[0051] Figure 4 This is the basic principle diagram of the lock-in amplifier;

[0052] Figure 5 is a schematic diagram of dissolved oxygen sensing;

[0053] Figure 6 is a schematic diagram of the signal processing components;

[0054] Figure 7 Schematic diagram of the oxygen-sensitive fluorescent film structure. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The present invention is based on detecting weak fluorescence signals under the interference of strong ambient background light at the marine ranch site, and adopts phase-locked amplification detection technology. In view of this, the present invention provides a dual-channel orthogonal phase-locked dissolved oxygen sensor device. Figures 1 to 6 As shown, a constant current processing module 23 is adopted and an LED light guide column is added to solve the problem of inconsistent luminous flux caused by process installation errors, and the measurement optical path is shielded to greatly reduce external environmental interference. Through orthogonal phase-locking technology and temperature compensation, real-time online in-situ detection is achieved with high accuracy, short response time, easy and reliable installation.

[0057] Specifically, the device includes: a device body 3, an outer protective shell is arranged outside the device body, and the outer protective shell is made of POM material with a waterproof grade of IP68. The internal components of the device body can be screwed with threads, which is convenient for disassembly, installation and use.

[0058] A fluorescent sensing film 5 is installed at the first end of the device body 3, and a four-wire twisted pair connector 4 is installed at the second end of the device body 3; the four-wire twisted pair connector 4 is connected to a data transmission line 21 and a power line 17 to realize data transmission and power supply to the device.

[0059] A fluorescence sensing film assembly 1 is arranged near the fluorescence sensing film 5; a temperature sensor 2 and an internal circuit main board are also installed on the device body 3; an excitation light source 9, a reference light source 8, a filter 6, a photodetector 10 and a signal processing assembly are arranged on the internal circuit main board;

[0060] The temperature sensor 2 includes a temperature compensation circuit, and the temperature sensor has an accuracy of up to 0.3%, stable testing, and high accuracy. Specifically, the temperature sensor uses a metal platinum resistor PT100, which has good detection accuracy and stability, and is small in size and easy to fix in the stainless steel ring of the dissolved oxygen sensor body. It is used to measure temperature and compensate for the temperature error of dissolved oxygen content measurement. With high-precision AD sampling, the temperature sensor has an accuracy of 0.3%, which greatly improves the accuracy and precision of dissolved oxygen measurement.

[0061] The filter 6 is arranged at the rear end of the fluorescence sensing film 5, and the photodetector 10 is arranged at the rear end of the filter 6; the temperature sensor 2 is arranged between the filter 6 and the fluorescence sensing film 5; here, the fluorescence sensing film 5 is arranged at the outermost end, and the filter 6 is arranged between the fluorescence sensing film 5 and the photodetector 10.

[0062] The excitation light source 9 and the reference light source 8 are installed at the first end of the device body 3, and the excitation light source 9 and the reference light source 8 are respectively in the same horizontal plane with the photodetector 10; the center of the excitation light source 9, the center of the reference light source 8 and the center of the photodetector 10 may be collinear. The excitation light source 9 irradiates the fluorescent sensing film so that the wavelength of the red light emitted by the exciting fluorescent sensing film and the wavelength of the red light excited by the reference light source 8 are within a preset range; wherein the excitation light source 9 is an exciting blue light LED light source, and the reference light source 8 is an exciting red light LED light source. The reference signal of the present invention is red light, which is triggered by blue light, the shifter is moved back 90°, and the reference light and the reference light are orthogonal. In order to reduce external interference, the excitation light and the photoelectric reception of the device are both treated with a shielding film to shield environmental interference.

[0063] The signal processing component is used to control the excitation light source 9 to emit light. The fluorescence signal and reference light signal generated by the excitation are detected by the photodetector 10 and converted into electrical signals. The electrical signals are processed and phase-locked amplified to obtain phase information. The phase information and temperature detection information are quantitatively analyzed to calculate the dissolved oxygen concentration data.

[0064] Exemplarily, the dual-channel orthogonal phase-locked dissolved oxygen sensor device includes a fluorescent sensing membrane, an outer protective shell, an inner circuit main board, a vulcanized sealed waterproof aviation plug kit, an outlet cable and a temperature sensor; the film layer of the fluorescent sensing membrane is a platinum porphyrin complex coated with an oxygen-sensitive fluorescent material, and the inner circuit main board is provided with an excitation light source 9, a reference light source 8, a filter 6, a photodetector 10 and a signal processing component; the filter is selected for light with a central wavelength of 610nm, the filter bandpass is 25nm, and can pass a wavelength range between 595nm-645nm, the photodetector 10 is a photodiode, which can convert the optical signal into an electrical signal and connect the signal processing circuit; the excitation light source 9 is an excitation blue light LED, and the reference light source 8 is an excitation red light LED, the excitation light source 9 irradiates the fluorescent film, and the wavelength of the red light emitted by the excitation fluorescent film is close to the wavelength of the red light excited by the reference light source 8; the temperature sensor 2 is arranged on the inner wall of the device body and fixed between the filter and the fluorescent sensing membrane to accurately measure the water temperature; the outlet cable is located outside the outer protective shell. The outer protective shell is a POM tube made of pressure-resistant and corrosion-resistant material.

[0065] Further speaking, if Figure 7 As shown, the fluorescent sensing film is a special molecule called platinum porphyrin, and the fluorescent substance is embedded and fixed into the polymer layer for fluorescence quenching. In order to maintain the oxygen sensitivity of the fluorescent indicator and prevent it from leaching into the water environment, it is coated on a polyester film carrier layer as the sensing membrane of the detector. In order to avoid the potential influence of fluorescent materials around the detector and the interference of external light, a black gas permeable coating is provided on the outside of the sensing layer. The coating provides optical isolation between the sensing layer and the surrounding environment. The fluorescent substance has a fluorescent property. When irradiated by blue light, the fluorescent indicator absorbs energy and the sensing layer will excite the red fluorescence. If there is dissolved oxygen around, the fluorescence will be quenched, reducing the lifetime and intensity of the fluorescence. Therefore, the amount of reflected red fluorescence will depend on the oxygen concentration in the oxygen sensitive membrane, and the fluorescence lifetime will decrease with the increase of oxygen concentration.

[0066] For the present invention, the signal processing components include: I / V conversion module 22, signal amplification filter 23, dual-channel orthogonal phase-locked module 11, AD converter 14, MCU module 15, power management module, communication module 13 and temperature compensation module of temperature sensor

[0067] It also includes: a power supply module 16 for supplying power to the electrical components inside the device; the photodetector 10 is connected to the MCU module 15 through the I / V conversion module 22, the signal amplification filter, the dual-channel orthogonal phase-locked module 11 and the AD converter 14 in sequence;

[0068] The MCU module controls the blue light LED to emit light, which generates a fluorescent signal. The blue light signal is delayed by 90° and then excites the red light LED to operate.

[0069] The temperature sensor 2 is connected to the MCU module 15 through the AD converter 14; the MCU module 15 is connected to the host computer through the communication module 13, and the calculated dissolved oxygen concentration data is uploaded to the host computer. The temperature compensation module of the temperature sensor is connected to the MCU module 15 to provide the MCU module 15 with a temperature compensation coefficient.

[0070] The signal amplifier filter pre-amplifies and filters the input signal. The reference channel of the signal amplifier filter adjusts the amplitude and phase of the reference input to meet the detection requirements of the subsequent circuit. The dual-channel orthogonal phase-locked module 11 is a phase-sensitive detector. Its working principle is to multiply the reference signal Vr(t) and the signal to be measured Vs(t) of the same frequency to generate a DC signal and a harmonic signal, and then filter out the harmonics through a low-pass filter, and finally output a DC signal, whose amplitude is related to the amplitude of the input signal and the reference signal and the phase difference between them.

[0071] The basic working principle of the fluorescence phase-locked amplification technology of the dual-channel orthogonal phase-locked module is:

[0072] The excitation light source 9 and the reference light source 8 emit light, and the photodetector is used to collect fluorescence.

[0073] The signal processing component generates a sinusoidal signal, which excites light modulation and serves as a reference signal for the phase-locked amplifier. The reference signal is adjusted to have the same frequency as the measured signal, and its phase information lags by 90°, so that it is correlated with the measured signal, while the possibility of being correlated with the noise signal is extremely small, thereby achieving effective extraction of weak signals.

[0074] The dual-channel orthogonal phase-locked module is a phase-sensitive detector. It generally uses a phase-sensitive detector and a low-pass filter to perform phase-sensitive synchronous detection to achieve frequency conversion, and uses a reference signal to perform phase-sensitive detection on the fluorescence signal to obtain the intensity and phase information of the fluorescence signal. The signal processing component collects the phase information of the fluorescence signal and calculates the dissolved oxygen content.

[0075] The MCU module processes the relationship between the phase difference and the dissolved oxygen concentration, and realizes the dissolved oxygen measurement of the entire sensor by adding a temperature compensation coefficient to the MCU module. The MCU module sends the analyzed dissolved oxygen concentration data to the host computer through the RS485 serial port. The host computer transmits data with the underwater detection unit through a custom communication protocol, and the design realizes the detection data collection, display and automatic storage.

[0076] The MCU module can control the LED to illuminate the sensitive film to stimulate fluorescence, and the generated fluorescence signal and reference light signal are detected by the photodetector 10 and converted into electrical signals.

[0077] The electrical signal detected by the photodetector 10 is transmitted to the dual-channel orthogonal phase-locked module after signal preprocessing such as conversion, amplification, and filtering. The phase information is obtained after the signal is modulated and demodulated, and the phase information and temperature detection information are quantitatively analyzed to calculate the dissolved oxygen concentration data. The quantitative analysis process requires the use of a calibration algorithm model established by quantitative analysis of temperature, phase, and dissolved oxygen concentration. The present invention comprehensively utilizes optical and electrical principles, greatly improves the signal-to-noise ratio of weak signals in circuit processing, has a short response time, high sensitivity, high precision, stable communication data, and can be remotely monitored online in real time.

[0078] The present invention also provides a dual-channel orthogonal phase-locked dissolved oxygen sensing system, comprising: a plurality of dual-channel orthogonal phase-locked dissolved oxygen sensing devices and a host computer;

[0079] The system architecture may include a plurality of dual-channel orthogonal phase-locked dissolved oxygen sensor devices, a network and a host computer. The network is a medium for providing a communication link between the dual-channel orthogonal phase-locked dissolved oxygen sensor device and the host computer. The network may include various connection types, such as wired, wireless communication links or optical fiber cables, etc.

[0080] It should be understood that, according to the implementation requirements, there may be any number of dual-channel orthogonal phase-locked dissolved oxygen sensor devices, networks and host computers. For example, the host computer may be a server cluster composed of multiple servers.

[0081] Users can use the dual-channel orthogonal phase-locked dissolved oxygen sensor device to interact with the host computer through the network to receive or send dissolved oxygen concentration data.

[0082] The signal processing components of each dual-channel orthogonal phase-locked dissolved oxygen sensor device are respectively connected to the host computer for communication, and the calculated dissolved oxygen concentration data is uploaded to the host computer.

[0083] The dual-channel orthogonal phase-locked dissolved oxygen sensing system provided by the present invention is a unit and algorithm step of each example described in combination with the embodiments disclosed herein, which can be implemented by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to the function. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0084] In one embodiment of the present invention, based on a dual-channel orthogonal phase-locked dissolved oxygen sensor device, a possible embodiment is given below to illustrate its specific implementation scheme in a non-limiting manner.

[0085] Among them, the dual-channel orthogonal phase-locked dissolved oxygen sensing method based on fluorescence method includes:

[0086] When the device is powered on, the signal processing component controls the operation of the excitation light source 9 and the reference light source 8 respectively;

[0087] The excitation light source 9 emits light, and the fluorescence signal and reference light signal generated by the excitation are detected by the photodetector 10 and converted into electrical signals;

[0088] The signal processing component processes the electrical signal and performs phase-locked amplification to obtain phase information, quantitatively analyzes the phase information and temperature detection information, and calculates the dissolved oxygen concentration data;

[0089] The signal processing component sends the analyzed dissolved oxygen concentration data to the host computer through the communication module;

[0090] The host computer transmits data with the dual-channel orthogonal phase-locked dissolved oxygen sensor device through a communication protocol to display and store the dissolved oxygen concentration data.

[0091] Furthermore, the method further includes: the MCU module 15 excites the blue light LED to emit light, excites and generates a fluorescent signal, and the blue light signal excites the red light LED to operate after a phase delay of 90°;

[0092] The excitation light source 9 generates an excitation light signal, which is irradiated onto the fluorescent sensing film, so that the wavelength of the red light emitted by the excited fluorescent sensing film is within a preset range with the wavelength of the red light excited by the reference light source 8;

[0093] The photodetector 10 detects and receives the fluorescent signal and converts the fluorescent signal into an electrical signal;

[0094] The signal processing component converts the current signal into a voltage signal, and the signal amplification filter amplifies and filters the voltage signal; the signal processing component modulates the excitation light and uses it as a reference signal for the phase-locked amplifier; the reference signal is adjusted to have the same frequency as the measured signal, and the phase information lags by 90°, so that the reference signal is correlated with the measured signal;

[0095] The signal processing component uses the reference signal to perform phase-sensitive detection on the fluorescence signal, obtains the intensity and phase information of the fluorescence signal, collects the phase information of the fluorescence signal and calculates the dissolved oxygen content; the signal processing component processes the relationship between the phase difference and the dissolved oxygen concentration, and realizes the dissolved oxygen measurement in combination with the temperature compensation coefficient.

[0096] The present invention combines the local atmospheric pressure value, salinity, and the measured temperature value to calculate the concentration of dissolved oxygen through a formula. The present invention comprehensively uses optical and electrical principles to greatly improve the signal-to-noise ratio of weak signals in circuit processing, with short response time, high sensitivity, high precision, stable communication data, and remote online real-time in-situ monitoring.

[0097] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-channel orthogonal phase-locked dissolved oxygen sensor device, characterized in that: include: A device body (3), a fluorescent sensing film (5) is installed at the first end of the device body (3), and a four-wire twisted pair connector (4) is installed at the second end of the device body (3); a fluorescent sensing film assembly (1) is arranged near the fluorescent sensing film (5); and a temperature sensor (2) and an internal circuit main board are also installed on the device body (3); An excitation light source (9), a reference light source (8), an optical filter (6), a photodetector (10), and a signal processing component are provided on the internal circuit main board; The filter (6) is arranged at the rear end of the fluorescent sensing film (5), and the photodetector (10) is arranged at the rear end of the filter (6); the temperature sensor (2) is arranged between the filter (6) and the fluorescent sensing film (5); The excitation light source (9) and the reference light source (8) are mounted on the first end of the device body (3), and the excitation light source (9) and the reference light source (8) are respectively located at the same horizontal plane as the photoelectric detector (10); the excitation light source (9) irradiates the fluorescent sensing film, so that the wavelength of the red light emitted by the excited fluorescent sensing film and the wavelength of the red light excited by the reference light source (8) are within a preset range; The signal processing component is used to control the excitation light source (9) to emit light, and the fluorescence signal and the reference light signal generated by the excitation are detected by the photoelectric detector (10) and converted into electrical signals, the electrical signals are processed and phase-locked amplified to obtain phase information, the phase information and the temperature detection information are quantitatively analyzed, and the dissolved oxygen concentration data are calculated; The signal processing component includes: an I / V conversion module (22), a signal amplification filter, a dual-channel orthogonal phase-locked module (11), an AD converter (14), an MCU module (15), a power management module, a communication module (13) and a temperature compensation module of a temperature measuring sensor; The photodetector (10) is connected to the MCU module (15) in sequence through the I / V conversion module (22), the signal amplification filter, the dual-channel orthogonal phase-locked module (11) and the AD converter (14); The MCU module controls the blue light LED to emit light, which generates a fluorescent signal. The blue light signal is delayed by 90° and then excites the red light LED to operate. The temperature sensor (2) is connected to the MCU module (15) via an AD converter (14); the MCU module (15) is connected to the host computer via a communication module (13) for communication, and the calculated dissolved oxygen concentration data is uploaded to the host computer; The temperature compensation module of the temperature measuring sensor is connected to the MCU module (15) and is used to provide a temperature compensation coefficient to the MCU module (15); The film layer of the fluorescent sensing film (5) is a platinum porphyrin complex coated with an oxygen-sensitive fluorescent material; The excitation light source (9) is an excitation blue light LED light source, and the reference light source (8) is an excitation red light LED light source; The filter (6) is selected for light with a central wavelength of 610 nm, and the filter (6) has a bandpass of 25 nm and passes a wavelength range of 595 nm to 645 nm; The temperature sensor (2) uses a metal platinum resistor PT100; The four-wire twisted pair connector (4) adopts a vulcanized sealed waterproof aviation plug.

2. The dual-channel orthogonal phase-locked dissolved oxygen sensor device according to claim 1, characterized in that: An outer protective shell is arranged outside the device body, and the outer protective shell is made of POM material with a waterproof grade of IP68.

3. The dual-channel orthogonal phase-locked dissolved oxygen sensor device according to claim 1, characterized in that: The four-wire twisted pair connector (4) is connected to a data transmission line (21) and a power line (17).

4. A dual-channel orthogonal phase-locked dissolved oxygen sensing system, characterized in that: include: A plurality of dual-channel orthogonal phase-locked dissolved oxygen sensor devices and a host computer as described in any one of claims 1 to 3; The signal processing components of each dual-channel orthogonal phase-locked dissolved oxygen sensor device are respectively connected to the host computer for communication, and the calculated dissolved oxygen concentration data is uploaded to the host computer.

5. A dual-channel orthogonal phase-locked dissolved oxygen sensing method based on fluorescence method, characterized in that: The method adopts the dual-channel orthogonal phase-locked dissolved oxygen sensor device as described in any one of claims 1 to 3; Methods include: When the device is powered on, the signal processing component controls the operation of the excitation light source (9) and the reference light source (8) respectively; The excitation light source (9) emits light, and the fluorescence signal and the reference light signal generated by the excitation are detected by the photodetector (10) and converted into electrical signals; The signal processing component processes the electrical signal and performs phase-locked amplification to obtain phase information, quantitatively analyzes the phase information and temperature detection information, and calculates the dissolved oxygen concentration data; The signal processing component sends the analyzed dissolved oxygen concentration data to the host computer through the communication module; The host computer transmits data with the dual-channel orthogonal phase-locked dissolved oxygen sensor device through the communication protocol to display and store the dissolved oxygen concentration data; The method also includes: The MCU module (15) excites the blue light LED to emit light, thereby generating a fluorescent signal. The blue light signal is delayed by 90° in phase and then excites the red light LED to operate. The excitation light source (9) generates an excitation light signal and irradiates the fluorescence sensing film, so that the wavelength of the red light emitted by the excited fluorescence sensing film is within a preset range with the wavelength of the red light excited by the reference light source (8); The photodetector (10) detects and receives the fluorescence signal and converts the fluorescence signal into an electrical signal; The signal processing component converts the current signal into a voltage signal, and the signal amplification filter amplifies and filters the voltage signal; The signal processing component modulates the excitation light and uses it as a reference signal for the phase-locked amplifier; the reference signal is adjusted to have the same frequency as the measured signal, and the phase information lags by 90°, so that the reference signal is correlated with the measured signal; The signal processing component uses the reference signal to perform phase-sensitive detection on the fluorescence signal, obtains the intensity and phase information of the fluorescence signal, collects the phase information of the fluorescence signal and calculates the dissolved oxygen content; The signal processing component processes the relationship between the phase difference and the dissolved oxygen concentration, and realizes the dissolved oxygen measurement in combination with the temperature compensation coefficient.

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