CN113063467A - Sensor-based oxygen concentration and effective flow measuring method and storage medium - Google Patents
Sensor-based oxygen concentration and effective flow measuring method and storage medium Download PDFInfo
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- CN113063467A CN113063467A CN202110468846.8A CN202110468846A CN113063467A CN 113063467 A CN113063467 A CN 113063467A CN 202110468846 A CN202110468846 A CN 202110468846A CN 113063467 A CN113063467 A CN 113063467A
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Abstract
The invention relates to the technical field of sensors, in particular to a sensor-based oxygen concentration and effective flow measurement method and a storage medium, wherein the oxygen concentration measurement method comprises the following steps: acquiring the time t1 taken by the second ultrasonic sensor to receive the signal sent by the first ultrasonic sensor and acquiring the time t2 taken by the first ultrasonic sensor to receive the signal sent by the second ultrasonic sensor; calculating the ultrasonic wave speed v under the current concentration according to the time t1, the time t2 and the hardware parameters of the sensor; acquiring the current temperature T in the sensor cavity, and calculating the oxygen concentration n according to the formula of the application, the ultrasonic wave velocity v, the current temperature T and a preset velocity correction parameter; based on the sensor structure designed by the application, the oxygen concentration measurement formula is provided in multiple experiments and tests, and the accuracy of the oxygen concentration value measured by the sensor and the measurement method is higher than that of the prior art.
Description
Technical Field
The invention relates to the technical field of sensors, in particular to a sensor-based oxygen concentration and effective flow measuring method and a storage medium.
Background
With the continuous improvement and improvement of living standard of people and the gradual enhancement of health requirements, oxygen inhalation becomes an important means in family and community rehabilitation. Oxygen inhalation is sometimes called as oxygen therapy, has obvious effect on partial diseases, can supply oxygen to anoxic tissues, and has use value on dissolving bubbles in blood, stimulating wound healing, and diseases such as bubble embolism, carbon monoxide poisoning, cyanide poisoning, unhealed wound, bone injury necrosis, soft tissue infection, cerebral edema and the like. Oxygen supply to premature infants, as well as those with serious disease or trauma, at ambient pressure is also an important life saving measure. Not only the oxygen-deficient patient needs to absorb oxygen, but also the normal people need to supplement certain oxygen in the natural environment. However, since many patients and oxygen users do not know the oxygen inhalation knowledge and the oxygen therapy is not standardized, what people need to inhale oxygen, how to inhale oxygen, and the concentration and flow rate of the inhaled oxygen are problems that each patient and oxygen user must know.
Various household oxygenerators are available in the market, and due to different oxygen generation principles, the use characteristics of the household oxygenerators are different. The oxygen generation principle of the household oxygen generator can be mainly divided into the following categories: molecular sieve principle, high molecular oxygen-enriched membrane principle, water electrolysis principle and chemical reaction oxygen production principle. Wherein the molecular sieve oxygen generator is the only mature oxygen generator with international standard and national standard. The molecular sieve type oxygen generator is an advanced gas separation technology, and a physical method (PSA method) directly extracts oxygen from air, namely the oxygen is used as it is, fresh and natural, the maximum oxygen generation pressure is 0.2-0.3 MPa, and the danger of high pressure, explosion and the like does not exist. The working principle of the method is mainly to utilize the physical adsorption and desorption technology of the molecular sieve. The oxygen generator is filled with molecular sieve, nitrogen in air can be adsorbed during pressurization, and the residual unabsorbed oxygen is collected and purified to obtain high-purity oxygen. The molecular sieve discharges the adsorbed nitrogen back to the ambient air during decompression, and can adsorb the nitrogen and prepare oxygen during next pressurization, and the whole process is a periodic dynamic circulation process without consumption of the molecular sieve.
Compared with hospitals with strong professional standardization degree, the reliability and effectiveness of oxygen inhalation at home by using the household oxygen generator are difficult to be ensured, so the requirement on the oxygen generator is relatively high. Not only is it required to be convenient for users to use, but also the accuracy in the aspects of oxygen concentration, flow rate and the like is guaranteed so as to be safe for users to use.
The ultrasonic oxygen concentration detection sensor carried by the household oxygenerator on the market at present has low accuracy of measuring the oxygen concentration.
Disclosure of Invention
The invention mainly solves the technical problem that the accuracy of measuring the oxygen concentration in the prior art is low.
The sensor-based oxygen concentration and effective flow measuring method is characterized in that the sensor comprises a cavity for ultrasonic transmission, a first ultrasonic sensor, a second ultrasonic sensor and a circuit unit for processing sensor signals;
the cavity is a cylindrical cavity, the first end and the second end of the cavity are sealed, and the first ultrasonic sensor and the second ultrasonic sensor are respectively arranged on the inner walls of the first end and the second end of the cavity; the side wall of the cavity is provided with an air inlet and an air outlet at positions close to the first end and the second end respectively, and the distance from the air inlet to the first end is equal to the distance from the air outlet to the second end; the circuit unit is used for driving one of the first ultrasonic sensor and the second ultrasonic sensor to transmit ultrasonic waves, receiving ultrasonic signals by the other one of the first ultrasonic sensor and the second ultrasonic sensor, and processing the received ultrasonic signals to obtain analog signals for time difference sampling;
the oxygen concentration measurement method includes:
acquiring a time difference t1 taken by the second ultrasonic sensor to receive a signal sent by the first ultrasonic sensor and acquiring a time difference t2 taken by the first ultrasonic sensor to receive a signal sent by the second ultrasonic sensor;
calculating the ultrasonic wave speed v under the current concentration according to the time t1, the time t2 and the hardware parameters of the sensor;
acquiring the current temperature T in a sensor cavity, and calculating the oxygen concentration n according to the ultrasonic wave velocity v, the current temperature T and a preset velocity correction parameter according to the following formula;
wherein Calibrap is a speed correction parameter with a value range of (-2, + 2).
In one embodiment, further comprising: the analog signal used for time difference sampling is amplified, so that the analog signal is in a saturated state, and phase difference can be eliminated to improve the precision of time difference sampling.
The analog signal for time difference sampling is saturated, so that the phase difference can be eliminated, and the time difference sampling precision can be improved.
In one embodiment, further comprising:
calculating to obtain the average gas linear flow velocity c according to the ultrasonic wave velocity v, the length L of the cavity, t1 and t 2;
obtaining the average flow velocity C of the gas surface according to the average flow velocity C of the gas line and a preset flow correction coefficient KA；
According to the average flow velocity C of the gas surfaceAAnd calculating the gas flow Q according to the hardware parameter information of the sensor cavity;
and calculating the effective flow of the oxygen according to the oxygen concentration n and the gas flow Q.
In one embodiment, the calculating the ultrasonic wave velocity v at the current concentration according to the time t1 and the time t2 and the hardware parameters of the sensor comprises:
calculating and calculating the ultrasonic wave velocity v under the current concentration according to the following formula;
wherein L is the length of the cavity of the sensor, and s is the distance from the air inlet to the first end of the cavity or the distance from the air outlet to the second end of the cavity.
In one embodiment, the calculating the gas line average flow velocity c according to the ultrasonic wave velocity v, the length L of the cavity and t1 and t2 comprises: calculating the linear average gas flow rate c by using the following formula;
in one embodiment, the average flow velocity C of the gas surface is obtained according to the average flow velocity C of the gas line and a preset flow correction coefficient KAThe method comprises the following steps: the average gas surface flow velocity C was calculated by the following formulaA；
Wherein K is a flow correction coefficient.
In one embodiment, said average flow velocity according to said gas surface CAAnd hardware parameter information of the sensor cavity calculates the gas flow Q, and the method comprises the following steps: calculating the gas flow Q according to the following formula;
wherein d is the diameter of the cylindrical cavity, CAThe average flow rate of the gas surface is indicated.
In one embodiment, the calculating the effective flow rate of oxygen according to the oxygen concentration n and the gas flow rate Q includes: the effective flow rate Q of oxygen is calculated by the following formulaIs effective；
QIs effective＝Q*n
Wherein Q represents a gas flow rate, and n represents an oxygen concentration.
In one embodiment, the sensor further comprises a temperature sensor disposed on the gas passage of the chamber for measuring a temperature value within the chamber, the temperature value being used for calculating the correction;
the circuit unit of the sensor comprises a processor module, an analog switch circuit and a power supply module;
the power module and the analog switch circuit are electrically connected with the processor module, and the power module is used for supplying power to the circuit unit; the analog switch circuit is respectively electrically connected with the first ultrasonic sensor and the second ultrasonic sensor, is used for controlling the switching of the working states of the first ultrasonic sensor and the second ultrasonic sensor, is also used for receiving the acquisition signals of the first ultrasonic sensor and the second ultrasonic sensor and sending the acquisition signals to the processor module, and the processor module is used for processing the acquisition signals and then outputting an oxygen concentration value and an effective flow value.
In one embodiment, the circuit unit further comprises a signal processing circuit, an input end of the signal processing circuit is connected with an output end of the analog switch circuit, and an output end of the signal processing circuit is connected with the processor module;
the signal processing circuit comprises a filter circuit used for filtering the acquired signal; the signal processing circuit further comprises an amplifying circuit for amplifying the acquired signal.
According to the method for measuring oxygen concentration and effective flow based on the sensor of the above embodiment, the sensor includes a cavity for ultrasonic transmission, a first ultrasonic sensor and a second ultrasonic sensor, and a circuit unit for processing sensor signals. The cavity is a cylindrical cavity, a first end and a second end of the cavity are sealed, and the first ultrasonic sensor and the second ultrasonic sensor are respectively arranged on the inner walls of the first end and the second end of the cavity; the side wall of the cavity is provided with an air inlet and an air outlet at positions close to the first end and the second end respectively, the distance from the air inlet to the first end is equal to the distance from the air outlet to the second end, and the circuit unit is used for driving the first sensor to emit ultrasonic waves and driving the second ultrasonic sensor to receive ultrasonic signals and processing the received ultrasonic signals to obtain analog signals for time difference sampling. The oxygen concentration measurement method of the present application includes: acquiring the time t1 taken by the second ultrasonic sensor to receive the signal sent by the first ultrasonic sensor and acquiring the time t2 taken by the first ultrasonic sensor to receive the signal sent by the second ultrasonic sensor; calculating the ultrasonic wave speed v under the current concentration according to the time t1, the time t2 and the hardware parameters of the sensor; acquiring the current temperature T in the sensor cavity, and calculating the oxygen concentration n according to the formula of the application, the ultrasonic wave velocity v, the current temperature T and a preset velocity correction parameter; based on the sensor structure designed by the application, the oxygen concentration measurement formula is provided in multiple experiments and tests, and the accuracy of the oxygen concentration value measured by the sensor and the measurement method is higher than that of the prior art.
Drawings
FIG. 1 is a schematic diagram of the overall structure of a sensor according to the present application;
FIG. 2 is a schematic diagram of a sensor circuit unit according to the present application;
FIG. 3 is a flow chart of an oxygen concentration measurement method of the present application;
fig. 4 is a flow chart of an effective flow measuring method according to the present application.
Detailed Description
The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in detail in order to avoid obscuring the core of the present application from excessive description, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.
Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where such sequence must be followed.
In the embodiment of the invention, the applicant designs a new sensor structure, and provides a measuring method for measuring oxygen concentration and effective flow based on the sensor structure through multiple experiments, wherein a formula in the measuring method and parameters in the formula are obtained through multiple experiments of the applicant, and the oxygen concentration and the effective flow measured by adopting the sensor and the method of the application are more accurate after experimental verification.
The first embodiment is as follows:
referring to fig. 1, the present embodiment provides an oxygen concentration and effective flow measurement sensor, which includes: a cavity 7 for ultrasonic transmission, a first ultrasonic sensor 1 and a second ultrasonic sensor 4. The cavity 7 is a cavity with a regular shape, so that the resistance of oxygen circulation is reduced, and the measurement result is more accurate. The first end and the second end of the cavity 7 are sealed, and the first ultrasonic sensor 1 and the second ultrasonic sensor 4 are respectively arranged on the inner walls of the first end and the second end of the cavity 7, and are specifically arranged at the center position of the inner walls; the side wall of the cavity 7 is provided with an air inlet 2 and an air outlet 3 at positions close to the first end and the second end respectively, and the distance from the air inlet 2 to the first end is equal to the distance from the air outlet to the second end. The two ultrasonic sensors of the embodiment acquire the oxygen concentration after the measurement data is processed by controlling the transceiving conversion of the two ultrasonic sensors, and the measurement precision is high and the stability is high through multiple experiments.
Specifically, the cavity 7 of the present embodiment is a cylindrical cavity, and the resistance of the cylindrical cavity to the flow of oxygen is the minimum, so that the measurement accuracy is higher. In other embodiments, the cavity 7 may be a rectangular or other regular cavity, such as a regular hexagon or an elliptic cylinder.
Wherein, the air inlet 2 and the air outlet 3 of this embodiment are located same water flat line, make the whole shape of sensor more regular like this, also conveniently let in gas, in other embodiments, air inlet 2 and air outlet 3 also can not set up on same water flat line. In the embodiment, the extending lines of the uniform cavities 7 of the air inlet 2 and the air outlet 3 are vertical, and the air inlet 2 and the air outlet 3 are both provided with small cylindrical air holes.
In this embodiment, the first ultrasonic sensor 1 and the second ultrasonic sensor 4 are both ultrasonic sensors with a transceiving function, the eigen frequencies of the first ultrasonic sensor 1 and the second ultrasonic sensor 4 can be selected or adjusted as required, the selected frequency in this embodiment is 40KHz, and in other embodiments, the sensors can be replaced by 400KHz, 3MHz, and the like. The transmission/reception conversion between the first ultrasonic sensor 1 and the second ultrasonic sensor 4 can be realized by controlling the first ultrasonic sensor 1 and the second ultrasonic sensor 4, for example, the first ultrasonic sensor 1 is controlled to transmit and the second ultrasonic sensor 4 is controlled to receive, and the second ultrasonic sensor 4 is controlled to transmit and the first ultrasonic sensor 1 receives after the control is switched.
Further, as shown in fig. 2, the sensor of this embodiment further comprises a temperature sensor 83, and the temperature sensor 83 is generally disposed on the gas passage of the chamber, for example, the temperature sensor 83 is disposed on the inner wall of the chamber 7 for measuring the temperature value in the chamber 7, preferably on the inner wall at the middle position of the chamber, and the measured temperature is more representative of the temperature in the chamber 7. The temperature sensor 83 of the present embodiment is made of a thermistor material having a negative temperature coefficient, and can accurately measure the temperature value in the cavity 7.
As shown in fig. 2, the sensor of the present embodiment further includes a circuit unit, and the circuit unit is configured to drive one of the first ultrasonic sensor and the second ultrasonic sensor to emit ultrasonic waves, receive ultrasonic signals, and process the received ultrasonic signals to obtain analog signals for time difference sampling. Specifically, the circuit unit includes a processor module 84, an analog switch circuit 81, and a power supply module 86. A power module 86 and an analog switch circuit 81 are electrically connected to the processor module 84, the power module 86 being used to supply power to the entire circuit unit. The power module 86 includes a power management circuit and a power conversion circuit, which can provide 5-12V dc power for the circuit unit, for example, generate different voltages, such as 3.3V and 5V, respectively, to power the modules. The analog switch circuit 81 is electrically connected to the first ultrasonic sensor 1 and the second ultrasonic sensor 4, and is configured to control the switching of the working states of the first ultrasonic sensor 1 and the second ultrasonic sensor 4, and the analog switch circuit 81 is further configured to receive the collected signals of the first ultrasonic sensor 1 and the second ultrasonic sensor 4 and send the signals to the processor module 84, where the processor module 84 is configured to process the collected signals and output an oxygen concentration value and an effective flow value.
The processor module 84 of the present embodiment employs an STM32 series chip, which captures the acquisition signal through the IO port. In other embodiments, the processor module 84 may be replaced with a 51-series, ARM-series, or Arduino, Raspy, or like microprocessor.
The circuit unit of this embodiment further includes a signal processing circuit 82, an input end of the signal processing circuit 82 is connected to an output end of the analog switch circuit 81, an output end of the signal processing circuit 82 is connected to the processor module 84, and the signal processing circuit 82 is configured to perform denoising processing on the acquired signal.
Specifically, the signal processing circuit 82 includes a filter circuit 821, where the filter circuit 821 is used to perform filtering processing on the collected signal, for example, performing filtering processing using a band-pass filter circuit to reduce the measurement error; the signal processing circuit comprises an amplifying circuit 822, wherein the amplifying circuit 822 is used for amplifying the collected signals, putting the signals into a saturated state, and reducing the measurement error by means of high-performance band-pass filtering. In addition, a signal conversion circuit is included for converting the collected analog signals into digital signals to be sent to the processor module 84.
Further, the circuit unit of this embodiment further includes a communication module 85, and the communication module 85 is electrically connected to the processor module 84 and is configured to send the oxygen concentration value and the effective flow value obtained by the processor module 84 to an upper computer.
Further, the sensor of the embodiment further includes a mounting plate 5, the cavity 7 is disposed on the front surface of the mounting plate, specifically, the middle position of the cavity 7 is fixed by the fixing member 6, the circuit unit is disposed on the back surface of the mounting plate, and the surface of the circuit unit is provided with an insulating layer for insulation. For example, a PCB is disposed on the back of the mounting board 5, the circuit part is entirely disposed in the PCB, and the wires of the first ultrasonic sensor 1, the second ultrasonic sensor 4 and the temperature sensor 83 are all routed through the PCB, so that the whole sensor has no exposed wires, reduces external noise or movement interference, and has a small overall volume and high safety.
Through a plurality of measurement experiments, the sensor of the embodiment is more accurate in measuring oxygen concentration and effective flow, high in precision and good in stability.
Example two:
based on the sensor provided in the first embodiment, the present embodiment provides an oxygen concentration measurement method, as shown in fig. 3, the method includes:
step 101: the time t1 taken for the second ultrasonic sensor to receive the signal emitted by the first ultrasonic sensor is acquired, and the time t2 taken for the first ultrasonic sensor to receive the signal emitted by the second ultrasonic sensor is acquired.
Specifically, the circuit unit is configured to drive one of the first ultrasonic sensor and the second ultrasonic sensor to emit ultrasonic waves, receive an ultrasonic signal, and process the received ultrasonic signal to obtain an analog signal for time difference sampling. And when the time difference is acquired, the analog signal for time difference sampling is amplified, so that the analog signal is in a saturated state, phase difference is eliminated, and time difference sampling precision is improved.
Step 102: and calculating the wave speed v of the ultrasonic wave at the current concentration according to the time t1 and the time t2 and the hardware parameters of the sensor.
Step 103: and acquiring the current temperature T in the sensor cavity, and calculating the oxygen concentration n according to the ultrasonic wave velocity v, the current temperature T and a preset velocity correction parameter. Specifically, in the present embodiment, the following formula is used to calculate the oxygen concentration n.
Wherein, T represents the acquired temperature value in the current sensor cavity, v is the ultrasonic wave velocity, Calibrap is the velocity correction parameter for correcting the cavity length L, and the value range is (-2, + 2). The specific determination steps are as follows: when the initial Calibrap is 0, the concentration at 95% oxygen is measured as n according to equation (1), and Calibrap can be calculated using the following equation.
In step 101, the present embodiment calculates the ultrasonic wave velocity v at the current concentration according to the following formula.
In formula (2), L is the length of the cavity of the sensor, and s is the distance from the inlet to the first end of the cavity or the distance from the outlet to the second end of the cavity.
And inputting a plurality of groups of different stimulation signals to the first ultrasonic sensor and the second ultrasonic sensor, and receiving corresponding acquisition signals. In order to make the measurement of oxygen concentration and effective flow more accurate in this embodiment, to the acquisition signal of first ultrasonic sensor and second ultrasonic sensor, carry out band-pass filtering to it through filter circuit and handle, remove noise interference wherein, for example, remove mechanical disturbance and air current influence, shield periodic noise interference, the accuracy of measurement, robustness and stability have been promoted, then amplify it and handle, make the acquisition signal amplified to the guard mode, thereby the accuracy and the stability of system measurement have been promoted, with the error that reduces the measurement, make the measured result more accurate. In addition, in the embodiment, the requirement on the working frequency of the processor module (namely, the MCU) is reduced, and the cost is reduced.
Further, as shown in fig. 4, the method for measuring an effective oxygen flow rate of the present embodiment includes:
step 201: and calculating the average gas linear flow velocity c according to the ultrasonic wave velocity v, the length L of the cavity, t1 and t 2.
Specifically, the present example calculates the linear average gas flow rate c using the following formula.
Step 202: obtaining the average flow velocity C of the gas surface according to the average flow velocity C of the gas line and a preset flow correction coefficient KAI.e. the average flow velocity of the gas surface in the direction of the normal to the cross-section of the chamber.
Specifically, in the present embodiment, the average flow velocity of the gas surface is calculated by the following formula.
K is a flow correction coefficient, the flow correction coefficient K is determined by a Reynolds number Re, the K value is related to whether the gas is laminar flow or turbulent flow, the calculation model is in a laminar flow state, and K is 4/3. In the embodiment, a flow correction coefficient is introduced, so that the measured oxygen flow is more accurate.
Step 203: average flow rate C according to gas levelAAnd calculating the gas flow Q according to the hardware parameter information of the sensor cavity.
Wherein the content of the first and second substances,
wherein d is the diameter of the cylindrical cavity, CAThe average flow rate of the gas surface is indicated.
Step 204: and calculating the effective flow of the oxygen according to the oxygen concentration n and the gas flow Q.
In this example QIs effective＝Q*n
Wherein Q represents a gas flow rate, and n represents an oxygen concentration.
By adopting the measuring method of the embodiment to measure the oxygen concentration and the effective oxygen flow, the measuring result has high precision and is more stable in measurement.
The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. For a person skilled in the art to which the invention pertains, several simple deductions, modifications or substitutions may be made according to the idea of the invention.
Claims (10)
1. The sensor-based oxygen concentration and effective flow measuring method is characterized in that the sensor comprises a cavity for ultrasonic transmission, a first ultrasonic sensor, a second ultrasonic sensor and a circuit unit for processing sensor signals;
the cavity is a cylindrical cavity, the first end and the second end of the cavity are sealed, and the first ultrasonic sensor and the second ultrasonic sensor are respectively arranged on the inner walls of the first end and the second end of the cavity; the side wall of the cavity is provided with an air inlet and an air outlet at positions close to the first end and the second end respectively, and the distance from the air inlet to the first end is equal to the distance from the air outlet to the second end; the circuit unit is used for driving one of the first ultrasonic sensor and the second ultrasonic sensor to transmit an ultrasonic signal, receiving the ultrasonic signal by the other one of the first ultrasonic sensor and the second ultrasonic sensor, and processing the received ultrasonic signal to obtain an analog signal for time difference sampling;
the oxygen concentration measurement method includes:
acquiring a time difference t1 taken by the second ultrasonic sensor to receive a signal sent by the first ultrasonic sensor and acquiring a time difference t2 taken by the first ultrasonic sensor to receive a signal sent by the second ultrasonic sensor;
calculating the ultrasonic wave speed v under the current concentration according to the time t1, the time t2 and the hardware parameters of the sensor;
acquiring the current temperature T in a sensor cavity, and calculating the oxygen concentration n according to the ultrasonic wave velocity v, the current temperature T and a preset velocity correction parameter according to the following formula;
wherein Calibrap is a speed correction parameter with a value range of (-2, + 2).
2. The sensor-based oxygen concentration and effective flow measurement method of claim 1, further comprising amplifying the analog signal for time difference sampling such that the analog signal is in saturation.
3. The sensor-based oxygen concentration and effective flow measurement method of claim 1, further comprising:
calculating to obtain the average gas linear flow velocity c according to the ultrasonic wave velocity v, the length L of the cavity, t1 and t 2;
obtaining the average flow velocity C of the gas surface according to the average flow velocity C of the gas line and a preset flow correction coefficient KA；
According to the average flow velocity C of the gas surfaceAAnd calculating the gas flow Q according to the hardware parameter information of the sensor cavity;
and calculating the effective flow of the oxygen according to the oxygen concentration n and the gas flow Q.
4. The sensor-based oxygen concentration and effective flow measurement method of claim 1, wherein said calculating the ultrasonic wave velocity v at the current concentration from the times t1 and t2 and the hardware parameters of the sensor comprises:
calculating and calculating the ultrasonic wave velocity v under the current concentration according to the following formula;
wherein L is the length of the cavity of the sensor, and s is the distance from the air inlet to the first end of the cavity or the distance from the air outlet to the second end of the cavity.
5. The sensor-based oxygen concentration and effective flow measurement method of claim 2, wherein said calculating a gas line average flow velocity c from said ultrasonic wave velocity v, the length L of the cavity, and t1 and t2 comprises: calculating the linear average gas flow rate c by using the following formula;
6. the sensor-based oxygen concentration and effective flow measuring method of claim 2, wherein the average flow velocity C of the gas surface is obtained according to the average flow velocity C of the gas line and a preset flow correction coefficient KAThe method comprises the following steps: the average gas surface flow velocity C was calculated by the following formulaA；
Wherein K is a flow correction coefficient.
7. The sensor-based oxygen concentration and effective flow measurement method of claim 2, wherein said average flow velocity C is based on said gas surfaceAAnd hardware parameter information of the sensor cavity calculates the gas flow Q, and the method comprises the following steps: calculating the gas flow Q according to the following formula;
wherein d is the diameter of the cylindrical cavity, CAThe average flow rate of the gas surface is indicated.
8. The sensor-based oxygen concentration and effective flow measurement method of claim 2, wherein said calculating an effective flow of oxygen from said oxygen concentration n and gas flow Q comprises: the effective flow rate Q of oxygen is calculated by the following formulaIs effective；
QIs effective＝Q*n
Wherein Q represents a gas flow rate, and n represents an oxygen concentration.
9. The sensor-based oxygen concentration and active flow measurement method of claim 1, wherein the sensor further comprises a temperature sensor disposed in the gas channel of the chamber for measuring a temperature value within the chamber, the temperature value being used to calculate the correction;
the circuit unit of the sensor comprises a processor module, an analog switch circuit and a power supply module;
the power module and the analog switch circuit are electrically connected with the processor module, and the power module is used for supplying power to the circuit unit; the analog switch circuit is respectively electrically connected with the first ultrasonic sensor and the second ultrasonic sensor, is used for controlling the switching of the working states of the first ultrasonic sensor and the second ultrasonic sensor, is also used for receiving the acquisition signals of the first ultrasonic sensor and the second ultrasonic sensor and sending the acquisition signals to the processor module, and the processor module is used for processing the acquisition signals and then outputting an oxygen concentration value and an effective flow value.
10. The sensor-based oxygen concentration and effective flow measurement method of claim 8, wherein said circuit unit further comprises a signal processing circuit having an input connected to the output of said analog switching circuit and an output connected to said processor module; the signal processing circuit comprises a filter circuit used for filtering the acquired signal; the signal processing circuit further comprises an amplifying circuit for amplifying the acquired signal.
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