CN214407602U

CN214407602U - Sensor for measuring oxygen concentration and effective flow

Info

Publication number: CN214407602U
Application number: CN202120906951.0U
Authority: CN
Inventors: 戴猛; 程永红; 杨婕; 朱应平; 雍珊珊; 赵文顺
Original assignee: Hubble Intelligent Sensor Shenzhen Co ltd
Current assignee: Hubble Intelligent Sensor Shenzhen Co ltd
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2021-10-15
Anticipated expiration: 2031-04-28

Abstract

The utility model relates to a sensor technical field, concretely relates to oxygen concentration and effective flow measurement sensor. It includes: the ultrasonic sensor comprises a cavity for ultrasonic transmission, a first ultrasonic sensor and a second ultrasonic sensor; the cavity is a cavity with a regular shape, 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. This embodiment adopts two ultrasonic sensor, through controlling its receiving and dispatching conversion, acquires the oxygen concentration that obtains after measurement data handles, and it is high and stable high to test measurement accuracy through many times.

Description

Sensor for measuring oxygen concentration and effective flow

Technical Field

The utility model relates to a sensor technical field, concretely relates to oxygen concentration and effective flow measurement sensor.

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 is easy to be interfered by temperature, mechanical vibration, airflow and the like, so that the accuracy of the measured oxygen concentration is low.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem of main solution is that the precision of current oxygen concentration sensor measuring oxygen concentration is low.

An oxygen concentration and effective flow measurement sensor, comprising: the ultrasonic sensor comprises a cavity for ultrasonic transmission, a first ultrasonic sensor and a second ultrasonic sensor;

the cavity is a cavity with a regular shape, 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.

Preferably, the cavity is a cylindrical cavity.

Preferably, the air inlet and the air outlet are located on the same horizontal line.

Preferably, the first ultrasonic sensor and the second ultrasonic sensor are both ultrasonic sensors having a function of transmitting and receiving.

Further, the temperature sensor is arranged on the inner wall of the cavity and used for measuring the temperature value in the cavity.

The device further comprises a circuit unit, wherein the circuit unit 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.

Furthermore, 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, an output end of the signal processing circuit is connected with the processor module, and the signal processing circuit is used for denoising acquired signals.

Further, the signal processing circuit comprises a filter circuit for performing filtering processing on the acquired signal;

the signal processing circuit further comprises an amplifying circuit for amplifying the acquired signal.

Furthermore, the circuit unit also comprises a communication module which is electrically connected with the processor module and used for sending the oxygen concentration value and the effective flow value obtained by the processor module to an upper computer.

The circuit board further comprises an installation plate, the cavity is arranged on the front face of the installation plate, the circuit unit is arranged on the back face of the installation plate, and an insulating layer for insulation is arranged on the surface of the circuit unit.

The oxygen concentration and effective flow measurement sensor according to the above embodiment includes: the ultrasonic sensor comprises a cavity for ultrasonic transmission, a first ultrasonic sensor and a second ultrasonic sensor; the cavity is a cavity with a regular shape, 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. This embodiment adopts two ultrasonic sensor, through controlling its receiving and dispatching conversion, acquires the oxygen concentration that obtains after measurement data handles, and it is high and stable high to test measurement accuracy through many times.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a sensor according to the present application;

fig. 2 is a schematic structural 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 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.

The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).

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 the present embodiment, the first ultrasonic sensor 1 and the second ultrasonic sensor 4 are both ultrasonic sensors having a function of transmitting and receiving an integrated body. 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 includes a temperature sensor 83, the temperature sensor 83 is disposed on the inner wall of the chamber 7 for measuring the temperature 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 including 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 power module 86 is used for supplying power to the whole circuit unit; 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

On the basis of the sensor provided in the first embodiment, the present embodiment provides an oxygen concentration measurement method, as shown in fig. 3, including:

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 K_AI.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 level_AAnd 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, C_AThe 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 Q_{Is 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. It is right to have used specific individual example above the utility model discloses expound, only be used for helping to understand the utility model discloses, not be used for the restriction the utility model discloses. To the technical field of the utility model technical personnel, the foundation the utility model discloses an idea can also be made a plurality of simple deductions, warp or replacement.

Claims

1. An oxygen concentration and effective flow measurement sensor, comprising: the ultrasonic sensor comprises a cavity for ultrasonic transmission, a first ultrasonic sensor and a second ultrasonic sensor;

2. The oxygen concentration and effective flow measurement sensor of claim 1, wherein the cavity is a cylindrical cavity.

3. The oxygen concentration and effective flow measurement sensor of claim 1, wherein the inlet and outlet ports are located on the same horizontal line.

4. The oxygen concentration and effective flow rate measurement sensor according to claim 1, wherein the first ultrasonic sensor and the second ultrasonic sensor are both ultrasonic sensors having a function of transmitting and receiving sound.

5. The oxygen concentration and effective flow measurement sensor of claim 1, further comprising a temperature sensor disposed on an inner wall of the chamber for measuring a temperature value within the chamber.

6. The oxygen concentration and effective flow measurement sensor of claim 5, further comprising a circuit unit comprising a processor module, an analog switching circuit, a power supply module;

7. The oxygen concentration and effective flow measurement sensor of claim 6, wherein the circuit unit further comprises a signal processing circuit, an input terminal of the signal processing circuit is connected to an output terminal of the analog switch circuit, an output terminal of the signal processing circuit is connected to the processor module, and the signal processing circuit is configured to perform denoising processing on the collected signal.

8. The oxygen concentration and effective flow measurement sensor of claim 7, wherein said signal processing circuitry includes filtering circuitry for filtering said collected signals; the signal processing circuit further comprises an amplifying circuit for amplifying the acquired signal.

9. The oxygen concentration and effective flow measurement sensor of claim 7, wherein the circuit unit further comprises a communication module electrically connected to the processor module for transmitting the oxygen concentration value and the effective flow value obtained by the processor module to an upper computer.

10. The oxygen concentration and effective flow rate measurement sensor according to claim 6, further comprising a mounting plate, wherein the cavity is provided on a front surface of the mounting plate, the circuit unit is provided on a rear surface of the mounting plate, and an insulating layer for insulation is provided on a surface of the circuit unit.