WO2018041068A1

WO2018041068A1 - Flow sensor for pulmonary function testing, spirometer and testing method and application thereof

Info

Publication number: WO2018041068A1
Application number: PCT/CN2017/099296
Authority: WO
Inventors: 王天星; 胡锡江; 陈志敏; 唐兰芳; 刘金玲; 吴磊
Original assignee: 台州亿联健医疗科技有限公司
Priority date: 2016-08-29
Filing date: 2017-08-28
Publication date: 2018-03-08

Abstract

A flow sensor for pulmonary function testing, an application thereof in a spirometer, and a pulmonary function testing method. The flow sensor for pulmonary function testing has a hollow tubular structure and comprises: an expiration inlet (1), a first cone (2), a throat section (3) and a second cone (4) sequentially connected. A tube wall of the throat section (3) is perforated with a low-pressure tap (5), and a tube wall of the expiration inlet (1) or the first cone (2) is perforated with a first high-pressure tap (6). The flow sensor and the spirometer have high test sensitivity and accuracy, simple structure, and low cost of use. The compact structure facilitates the miniaturization, calibration and correction of a spirometer and is easy for after-sales maintenance.

Description

Flow sensor, lung function meter and detection method and application for pulmonary function detection

Technical field

The present invention relates to the field of medical diagnosis, and more particularly to a flow sensor for pulmonary function detection, a pulmonary function meter, and a method of using the same for pulmonary function detection.

Background technique

Pulmonary function test can judge the ventilator function of the tester, and has practical clinical significance in identifying the type of airway obstruction and the evaluation of lung function before thoracic and abdominal surgery.

At present, commonly used pulmonary function instruments include a bellows type portable lung function meter, a turbo type portable lung function meter, an ultrasonic flow rate sensing type portable lung function meter, and a differential pressure portable lung function meter. The detection principle of the bellows type portable lung function meter is that the inflator blows air into the bellows to expand the airbag in the bellows to push the marker pen, and the appearance thereof is light, but the parameters that can be measured are small. The detection principle of the turbo portable lung function meter is designed according to the characteristics that the rotational speed of the rotating component (turbine) is proportional to the fluid velocity. When the gas passes, the turbine rotates, and the photoelectric rotation effect is used to convert the turbine rotation signal into an electrical signal output. The disadvantage is that the impeller can still rotate with inertia when the airflow stops, and the inertia and the bearing friction torque will affect the accuracy of the sensor, and it will easily pollute the turbine and cause cross-contamination. The principle of the ultrasonic flow rate sensing type portable lung function meter is based on the relationship between the time difference of sound waves transmitted on the forward and reverse air streams and the gas flow rate. The faster the flow rate, the greater the time difference and the flow rate is calculated from the time difference. However, the scope of consistency is still large, and some indicators have poor repeatability and high product cost. The differential pressure portable pulmonary function meter currently uses Fleisch and the modified Lilly differential pressure flow meter. The flow velocity sensor has a sieve-like mesh. When the airflow passes through the mesh, the flow velocity decreases due to the resistance of the mesh. As a result, the pressure at the other end of the mesh is slightly lowered, and a pressure drop difference is formed at both ends of the mesh. The pressure difference sensor passes the gas flow rate. The generated differential pressure signal is converted into an electrical signal, which is processed and output in digital or graphical form. The disadvantage of this technique is that the exhaled water vapor is easily condensed and deposited on the sieve-like mesh to block the mesh, and the cleaning and disinfection of the mesh is difficult, thereby affecting the test accuracy and easily causing cross-contamination; in addition, the error is large when measuring at high flow rate. The measured results cannot be converted to and from the standard instrument, and calibration is required after cleaning and maintenance.

Pulmonary function tests include ventilation function, ventilation function, respiratory regulation function and pulmonary circulation function. The detection of multiple pulmonary function physiological parameters requires continuous detection of respiratory airflow. At present, the judgment method of the pulmonary function meter for the exhalation state or the inhalation state is generally compared with the zero point value of the differential pressure sensor, so the zero point value needs to be It is cumbersome to have a professional perform calibration with the software. During calibration, the standard 3L calibration cylinder is used for multiple times to simulate the exhalation and inspiration of the human body. Since the expiratory volume of the calibration cylinder is equal to the inspiratory volume of 3L, the corresponding sensor can be obtained by calculating the half of the total volume. The output value is the zero value of the sensor, the value greater than zero is exhaled, and the value less than zero is inspiratory. The temperature and humidity of the environment, the change of atmospheric pressure, and the frequency of use will cause the zero point of the sensor to drift. Therefore, it is necessary to periodically calibrate the zero value of the sensor, otherwise a large error will occur.

Summary of the invention

In order to overcome the above disadvantages, one of the objects of the present invention is to provide a flow sensor for pulmonary function detection, which is a hollow tube structure mainly composed of an exhalation air inlet portion, a first cone portion, and a throat portion. The second portion and the second cone portion are connected in sequence, and the low pressure pressure tapping opening is formed on the wall of the throat portion, and the first high pressure pressure tapping opening is opened on the exhalation air inlet portion or the first cone portion, and the exhalation air inlet portion The diameter of the throat portion is larger than the diameter of the throat portion, and the first tapered portion and the second tapered portion are respectively connected to the throat portion.

Further, the exhalation air inlet has a diameter of 16 to 30 mm, and the throat portion has a diameter of 10 to 13 mm.

The invention provides a flow sensor for detecting lung function, which is a hollow tube structure, which is mainly composed of an exhalation air inlet portion, a first cone portion, a throat portion and a second cone portion, and is connected by a low pressure. The mouth is opened on the wall of the throat, and the first high pressure port and the second high pressure port are respectively opened on the pipe walls on both sides of the non-throat portion.

Further, the exhalation air inlet portion and the throat portion are cylindrical, the diameter of the exhalation air inlet portion is larger than the diameter of the throat portion, and the first cone portion and the second cone portion are in a truncated cone shape, the first cone portion and the second portion The smaller diameter end of the taper is connected to the throat portion.

Further, the first pressure tapping opening is opened in the first taper portion or the expiratory air inlet portion, and the second high pressure tapping port is opened in the second taper portion.

Preferably, the distance between the first high pressure port and the low pressure port is smaller than the distance between the second high pressure port and the low pressure port.

The invention provides a pulmonary function meter comprising a differential pressure sensor and a flow sensor, wherein the flow sensor is a hollow tube structure mainly composed of an exhalation air inlet portion, a first cone portion, a throat portion and a second cone portion. Connected in sequence, the low pressure pressure port is opened on the wall of the throat, the first high pressure port is opened on the exhalation air inlet or the first cone, and the diameter of the exhalation air inlet is larger than the throat Diameter, diameter of the first cone and the second cone The small ends are connected to the throat. The differential pressure sensor is connected to the pressure port of the flow sensor.

The invention also provides another pulmonary function meter, comprising a differential pressure sensor and a flow sensor, wherein the flow sensor is a hollow tube structure mainly composed of an exhalation air inlet portion, a first cone portion, a throat portion and a second portion. The taper portions are connected in sequence, and the low pressure pressure tapping opening is formed on the pipe wall of the throat portion, and the first high pressure pressure tapping port and the second high pressure tapping port are respectively opened on the pipe walls on both sides of the non-throat mouth portion; The differential pressure sensor includes a first differential pressure sensor and a second differential pressure sensor. The differential pressure sensor is connected to the pressure port of the flow sensor, and includes a first differential pressure sensor and a second differential pressure sensor.

Further, the exhalation air inlet portion and the throat portion are cylindrical, the diameter of the exhalation air inlet portion is larger than the diameter of the throat portion, and the first cone portion and the second cone portion are in a truncated cone shape, the first cone portion and the second portion The smaller diameter end of the tapered portion faces the throat portion, respectively.

Further, the first high pressure pressure port of the flow sensor is connected to the positive pressure end of the first differential pressure sensor, the second high pressure pressure port is connected to the positive pressure end of the second differential pressure sensor, and the low pressure end of the two differential pressure sensors is passed The tee is connected to the low pressure port of the throat.

Further, the pulmonary function meter further includes a microprocessor. The data of the differential pressure sensor is controlled and collected by a microprocessor.

Preferably, the pulmonary function meter further comprises an automatic judgment system module for two detection modes of breath detection and inspiratory detection.

The invention also provides a method for detecting lung function, comprising the following steps:

(1) providing the aforementioned pulmonary function meter having a first high pressure port, a second high pressure port and a low pressure port;

(2) The tester's mouth contains the front end of the expiratory air intake of the flow sensor, and exhales or inhales;

(3) reading the first differential pressure sensor and the second differential pressure sensor data;

(4) Judging whether the tester is performing exhalation or inhalation;

(5) If the judgment is an exhalation state, the lung function meter reads the data of the first differential pressure sensor; if the inhalation state is determined, the lung function meter takes the data of the second differential pressure sensor;

(6) In step 5, the lung function detection parameter of the tester is calculated according to the obtained data of the first differential pressure sensor or the data of the second differential pressure sensor.

The method for determining exhalation or inhalation in step (4) comprises: comparing the pressure difference values of the two differential pressure sensors to determine whether the tester performs exhalation or inhalation on the flow sensor; or the operator according to the test The current or upcoming action determines whether the tester is exhaling or inhaling the flow sensor.

The present invention also provides a method for judging exhalation or inhalation during continuous respiratory gas detection, comprising a first differential pressure sensor for expiratory detection and a second differential pressure sensor for inhalation detection; Comparing the pressure difference between the first pressure difference sensor and the second pressure difference sensor; if the pressure difference value of the first pressure difference sensor is greater than the pressure difference value of the second pressure difference sensor, determining the exhalation state; When the pressure measurement value of the second differential pressure sensor is larger than the pressure difference value of the first differential pressure sensor, it is determined to be an intake state.

Further, a flow sensor is provided, which is a hollow tube structure, which is mainly formed by sequentially connecting an exhalation air inlet portion, a first cone portion, a throat portion and a second cone portion, and the low pressure pressure tap opening is opened at the throat portion. On the pipe wall of the portion, the first high pressure port and the second high pressure port are respectively opened on the pipe walls on both sides of the non-throat portion.

The invention also provides the use of the flow sensor for preparing a pulmonary function meter.

The beneficial effects of the invention are:

The flow sensor of the present invention adopts a structure in which the diameter of both ends is larger than the intermediate diameter, and the size of each part of the sensor is optimized by calculation, so that the flow sensor size of the lung function detection can be applied to both the patient's mouth blow and the flow sensor in two. There is no turbulence near the pressure port, ensuring sensitivity and accuracy of measurement, reusable, no calibration, and easy to use.

The present invention utilizes the principle of fluid dynamics, that is, the pressure at a position where the cross-sectional area of the air flow in the flow passage is large is larger than the pressure at a position where the cross-sectional area is small, and the flow sensor is located at a pressure difference between the high pressure port and the low pressure port. The lung function meter microprocessor (host) can calculate and analyze various functional indexes of the lungs of the sick patients according to the pressure difference between the high and low pressure pressure ports, so that the doctor or the patient can judge the condition or confirm the curative effect. Using the difference in diameter fixed by different hole segments, the appropriate gradient of the difference in diameter can be calculated and analyzed to ensure that the pressure difference between the high and low pressure ports can be obtained, which ensures the sensitivity and accuracy of the measurement.

The flow sensor of the invention also adopts a low-pressure sampling port and two high-pressure sampling ports, which can The two-way flow of exhalation and inhalation is detected, and the convenient calibration and calibration methods are convenient for after-sale maintenance and miniaturization of the pulmonary function meter.

The pulmonary function meter of the invention can quickly switch between the breath detection mode and the inspiratory detection mode, and the judgment of exhalation or inspiration does not depend on the zero value of the sensor output, so there is no need to periodically calibrate the sensor exhalation The zero value of the gas conversion ensures the accuracy of the test.

DRAWINGS

Figure 1 is a schematic view showing the structure of a flow sensor having two pressure tapping holes according to the present invention.

2 is a schematic structural view of a flow sensor of three pressure tapping holes according to the present invention.

Figure 3 is a schematic view showing the structure of a three-hole flow sensor with an intake air intake.

Figure 4 is a schematic diagram of the connection of a three-hole flow sensor to a differential pressure sensor.

Figure 5 is a circuit block diagram of the pulmonary function meter of the present invention.

Figure 6 is a block diagram of the inspection process.

detailed description

The flow sensor for lung function detection shown in FIG. 1 is a hollow tube structure, which is formed by sequentially connecting the exhalation air inlet portion 1, the first cone portion 2, the throat portion 3, and the second cone portion 4. The low pressure pressure tap 5 opened on the wall of the throat is opened at the first high pressure port 6 on the wall of the first cone. The exhalation air inlet 1 and the throat portion 3 have a cylindrical shape, and the diameter of the exhalation air inlet portion is larger than the diameter of the throat portion. The first tapered portion 2 and the second tapered portion 4 have a truncated cone shape, and the first tapered portion and the second tapered portion have a smaller diameter end connected to the throat portion. The exhalation air inlet is the inlet section, the first cone is the contraction section, and the second cone is the diffusion section. The exhalation air intake portion 1, the first tapered portion 2, the throat portion 3, and the second tapered portion 4 are sequentially passed from one end of the air blown flow sensor to the other end of the air blown.

In a specific embodiment, in order to conform to the ergonomic principle, it is particularly suitable for the practical use of exhaling in the entrance of a patient, and it is suitable to set the diameter of the exhalation air inlet to 16 to 30 mm. According to the fluid dynamics Bernoulli equation and the principle of mass conservation continuity, the relationship between flow and pressure difference satisfies the formula

In the formula, the flow rate of human exhalation is about 50L/min to 900L/min, and the measurement range of the pressure difference of the lung function meter is 0-9kPa, and the diameter d of the throat section is calculated to be 10 to 13mm. Through a large number of experiments, the diameter D of the expiratory air inlet is 16 to 30 mm, and the diameter d of the throat is 10 to 13 mm. The exhalation air inlet and the throat are in a laminar flow during the detection process. Stable pressure difference, so that the lung function instrument host can accurately calculate and analyze various functional indicators of the lungs of the sick patients, so that the doctor or the patient can accurately judge the condition and the efficacy confirmation.

In a specific embodiment, the exhalation air inlet has a diameter D of 25 mm and the throat portion has a diameter d of 12 mm. This not only makes the stable pressure difference have a higher safety factor, but also makes the flow sensor have a compact appearance, and the pulmonary function test result is in good agreement with the actual condition of the patient's lung function.

In a more specific embodiment, the total length L of the flow sensor is 100 mm, the diameter D of the expiratory air inlet is 25 mm, the length L1 is 45 mm, the diameter d of the throat portion is 12 mm, and the length L2 of the throat portion is 10 mm. The first tapered portion has a truncated cone shape, and the large-diameter end of the first tapered portion is connected to the expiratory air inlet portion, the small-diameter end of the first tapered portion is connected to the throat portion, and the second tapered portion is also in the shape of a truncated cone. The small-diameter end of the second tapered portion is connected to the throat portion, the large-diameter end of the second tapered portion faces the blowing end of the hollow tube air, the length L3 of the second tapered portion is 30 mm, and the second tapered portion is opposite to the two bus bars The angle between the angle (taper angle) θ is 30°, the high pressure pressure tapping port is located at the position of the exhalation air inlet close to the first cone portion, and the high pressure pressure tapping port is connected with the exhalation air inlet portion, and the low pressure pressure tapping port Located at the middle of the throat, the low pressure pressure port is connected to the throat, and the high pressure pressure port and the low pressure pressure port have a diameter of 1.2 mm.

The outer surface of the first cone portion and the second cone portion of the flow sensor is provided with a post 11 , and the flow sensor is coupled to the pulmonary function meter through the post 11 .

Example 1

The flow sensor (experimental group, the present invention) prepared according to the above parameters was compared with the existing sensor (control group, prior art), and the experimental results were compared as follows:

It can be seen from the above experimental test data that the flow sensor of the present invention has higher detection sensitivity and accuracy than the flow sensor of the prior art.

FIG. 2 is another flow sensor for detecting lung function according to the present invention, which is a hollow tube structure including an exhalation air inlet portion 1, a first cone portion 2, a throat portion 3, and a second cone. The portions 4 are connected in sequence, and the low pressure pressure tap 5 is opened on the wall of the throat portion, and the first high pressure pressure port 6 and the second high pressure pressure port 7 are respectively opened on the tube walls on both sides of the non-throat portion. . The exhalation air inlet 1 and the throat portion 3 have a cylindrical shape, and the diameter of the exhalation air inlet portion is larger than the diameter of the throat portion. The first tapered portion 2 and the second tapered portion 4 have a truncated cone shape, and the first tapered portion and the second tapered portion have a smaller diameter end connected to the throat portion.

The first pressure tapping port 6 can be opened in the first taper portion 2 or the expiratory air inlet portion 1. The second high pressure port 7 can be opened in the second taper 4. As shown in FIG. 3, in the embodiment in which the end of the second tapered portion having a larger diameter is connected to the intake air intake portion 8, the second high pressure pressure receiving port 7 may be opened in the intake air intake portion 8. When the lung function parameter at the time of exhalation is detected, the pressure difference between the first high pressure port and the low pressure port is detected by the differential pressure sensor. When the lung function parameter at the time of inhalation is detected, the pressure difference between the second high pressure port and the low pressure port is detected by the differential pressure sensor. The pulmonary function meter calculates and analyzes various functional indexes of the tester's lungs according to the pressure difference between the high and low pressure pressure ports, and provides them to the doctor or the tester to judge the condition or confirm the curative effect.

In the embodiment in which the parameters of the maximum diameter of the pipe body of the flow sensor, the length of the pipe body, the first taper taper angle θ ₁ and the second taper taper angle θ ₂ are fixed, the first high pressure port is adjusted and the low pressure is taken. The distance between the mouths is obtained, and the sensitivity required for the breath detection is obtained. By adjusting the distance between the second high pressure port and the low pressure port, the sensitivity required for the inhalation detection is obtained.

In the embodiment where the pressure difference point of the differential pressure sensor is fixed, that is, the distance between the high and low pressure pressure ports of the flow sensor matched thereto is fixed, by adjusting the diameter of the exhalation air inlet of the flow sensor, The throat diameter, the first taper taper angle θ ₁ and its length, or the second taper taper angle θ ₂ and its length, obtain the detection range required for breath detection.

Since the maximum expiratory flow rate of the lung function test is much larger than the maximum inspiratory flow rate, in order to improve the sensitivity of the inspiratory flow detection, it is necessary to increase the pressure of the second high pressure port. According to the fluid dynamics Bernoulli principle, the relationship between the flow rate and the differential pressure satisfies the formula (I), where d is the diameter at the low pressure port of the throat and D is the diameter at the second high pressure port of the suction inlet. , ρ is the density of the fluid. When D becomes larger, the pressure difference Δp corresponding to a certain flow rate becomes correspondingly larger.

In a specific embodiment, by increasing the distance between the second high pressure port 7 and the low pressure port 5, the second high pressure port is opened at the larger diameter of the second taper 4 to increase The differential pressure output corresponding to the suction flow rate. By adjusting the positions of the first high pressure port and the second high pressure port, the flow detection of exhalation and inspiration meets the range and sensitivity requirements, and the differential pressure between the expiratory pressure difference sensor and the suction air pressure difference sensor can be made. The detection range is the same, that is, the same type of differential pressure sensor can be used, and the calibration and calibration of the differential pressure sensor adopt the same method, and the range of the correction coefficient is consistent. This facilitates the calibration and calibration of the pulmonary function meter.

The humidity of the gas exhaled by the human body is large, and the inside of the flow sensor is easy to condense water vapor. In order to prevent the condensed water from clogging the pressure tapping port, in a specific embodiment, the pore diameter of the pressure tapping port is 0.8 to 2 mm, and the water droplets condensed by the patient's exhaled air are in the water droplets. Under the action of surface tension, it will not enter the high and low pressure pressure ports or stay near the high and low pressure pressure ports, so that the flow sensor will not affect the detection accuracy and sensitivity even if it is used for a long time. For example, the high pressure pressure tap and the low pressure pressure tap have a pore diameter of 1.2 mm. At the same time, the high pressure pressure tapping opening is opened on the taper portion, so that the condensed water can flow out without staying at the pressure tapping port, and the throat portion is as short as possible, for example, less than 6 mm, to ensure that the water vapor is not retained in the throat portion.

As shown in Figure 4, the pulmonary function meter includes a differential pressure sensor and the flow sensor of Figure 2 of the present invention. The first high pressure port 6 of the first cone portion of the flow sensor is connected to the positive pressure end 103 of the first differential pressure sensor 101, and the positive pressure of the second high pressure port 7 and the second differential pressure sensor 102 of the second taper portion The end 103 is connected, and the low pressure end 104 of the two differential pressure sensors are respectively connected to the low pressure pressure port 5 of the throat through the tee 105 Pick up.

The differential pressure sensor can be connected to the microprocessor 106. The microprocessor is used to collect and process the signal of the differential pressure sensor, and calculate and analyze various functional indexes of the tester according to the pressure difference between the high and low pressure pressure tapping ports. A reference indicator of the current physical condition or therapeutic effect of the tester. The microprocessor may be provided by a pulmonary function meter or may be an external device such as a computer.

The pulmonary function meter also includes an automatic judgment system for two detection modes of breath detection and inspiratory detection. The automatic judgment system can determine exhalation or inspiration during the continuous function of the pulmonary function meter. When the airflow in the flow sensor is the expiratory flow, the pressure difference between the first high pressure port and the low pressure port is detected by the data of the first differential pressure sensor to obtain the lung function parameter during exhalation. When the airflow in the flow sensor is the inspiratory flow, the data of the second differential pressure sensor is used to detect the pressure difference between the second high pressure port and the low pressure port to obtain the lung function parameter during inhalation.

The exhalation inspiratory automatic judgment system may be a part of the pulmonary function detection software, and the switching between the exhalation detection and the inspiratory detection is realized by the program control. Especially when continuous inhalation or exhalation is required, the automatic judgment system can quickly switch between the breath detection mode and the inhalation detection mode.

When detecting the exhalation parameter, the airflow first passes through the first high pressure pressure port and then enters the low pressure pressure port of the throat. Since the throat portion has a small aperture, the airflow is compressed and accelerated, the pressure loss flow rate decreases, and finally passes through the second high voltage. Taking the pressure port, the differential pressure detection value of the first differential pressure sensor is always greater than the differential pressure detection value of the second differential pressure sensor; when detecting the suction parameter, the airflow first passes through the second high pressure pressure port and then enters the throat portion The low pressure pressure port, the air flow is compressed and accelerated, the pressure loss flow rate decreases, and finally passes through the first high pressure pressure port, so the differential pressure detection value of the second differential pressure sensor is always greater than the differential pressure detection value of the first differential pressure sensor. Therefore, in a specific embodiment, the exhalation inspiratory automatic judgment system compares the pressure difference values of the two differential pressure sensors to determine whether the current tester is exhaling or inhaling, and according to the result of the judgment, the detector automatically switches to the corresponding Breath detection mode or inspiratory detection mode.

Figure 5 is a circuit schematic diagram of the pulmonary function meter of Figure 4, including first and second differential pressure sensors, signal amplification circuits, dual channel A/D conversion circuits, microprocessor circuits, display screens, power management circuits, Power and buttons. When in use, press the button to start the lung function test, the tester continuously exhales the inhalation to the flow sensor, and the differential pressure sensor amplifies the measured signal, digital-analog conversion and sends it to the microprocessor for processing, and the processed information is processed. Displayed on the display. The power supply supplies power to the above units through a power management circuit.

As shown in FIG. 6, a method for detecting lung function includes the following steps:

(1) providing a pulmonary function meter according to the present invention;

(3) reading the first and second differential pressure sensor data;

(4) Determine whether to start exhaling or inhaling;

(5) determining whether it is an exhalation state, if the judgment is yes, the lung function meter takes the data of the first differential pressure sensor; if the determination is no, the lung function meter takes the data of the second differential pressure sensor;

(6) The microprocessor of the pulmonary function meter obtains data of the first or second differential pressure sensor to calculate the gas flow rate;

(7) Obtain lung function test parameters.

Step (5) determining the breathing state: comparing the pressure difference values of the two differential pressure sensors to determine whether the tester is exhaling or inhaling to the flow sensor; or the operator is currently or about to perform according to the tester. Action to determine whether the tester is exhaling or inhaling the flow sensor.

The flow sensor or lung function meter of the invention can be applied to routine physical examination, athlete physical strength test, daily monitoring of asthma patients, identification of airway obstruction type, pulmonary function evaluation before thoracic and abdominal surgery.

Example 2

The experimental group 1 is the three-hole flow sensor described in FIG. 2, the exhalation air inlet portion has a diameter of 27 mm, the first taper portion has a taper angle of 40 degrees, the throat portion has a diameter of 12 mm, and the second taper portion has a taper angle of At 25.4 degrees, the suction intake has a diameter of 27 mm. The distance between the first high pressure port and the low pressure port is 20 mm, and the distance between the second high pressure port and the low pressure port is 25 mm.

The experimental group 2 is the two-hole flow sensor shown in Fig. 1. The exhalation air inlet has a diameter of 27 mm, the taper angle of the first taper portion is 40 degrees, the throat portion diameter is 12 mm, and the taper angle of the second taper portion is At 25.4 degrees, the suction intake has a diameter of 27 mm. The distance between the first high pressure port and the low pressure port is 20 mm.

The measured values of the flow sensor of the experimental group 1 and the flow sensor of the experimental group 2 were compared with the standard flow value, and the test results are shown in Tables 1 and 2.

Table 1 experimental group 1 flow sensor breath inhalation experimental data

Table 2 Experimental group 2 flow sensor breath inhalation experimental data

It can be seen from the above experimental test data that the three-hole flow sensor shown in FIG. 2 is more accurate than the two-hole flow sensor shown in FIG. 1 during the detection of the inhalation parameter.

Example 3

Detecting the maximum pressure difference of the flow sensor of the experimental group 1 in the experimental group 1, the maximum expiratory flow range is 900 L/min, and the corresponding differential pressure is 10 kPa when the maximum flow rate; the maximum inspiratory flow range is 600 L/min, and the corresponding differential pressure is 10 kPa when the maximum flow rate is reached. . Therefore, the first differential pressure sensor and the second differential pressure sensor can use the same range of differential pressure sensors. Two sensors were calibrated by experimentally testing flow and differential pressure data (see Table 3). For specific correction, the two differential pressure sensors are connected in parallel and the same pressure difference is applied, and two pressure difference points of 1 kPa and 5 kPa are respectively taken for linear correction.

table 3

Claims

The flow sensor for detecting pulmonary function is a hollow tube structure, which is characterized in that it comprises an exhalation air inlet portion, a first cone portion, a throat portion and a second cone portion, and is connected in sequence, and the low pressure pressure port is opened. On the wall of the throat, the first high pressure port is opened on the wall of the expiratory air inlet or the first cone.
The flow sensor of claim 1 further comprising a second high pressure port, the second high pressure port being disposed on the wall of the second taper.
The flow sensor according to claim 1, wherein the diameter of the exhalation air inlet portion is larger than the diameter of the throat portion, and the ones having the smaller diameters of the first taper portion and the second taper portion are respectively connected to the throat portion.
The flow sensor according to claim 1, wherein the exhalation air inlet has a diameter of 16 to 30 mm and the throat portion has a diameter d of 10 to 13 mm. .
The pulmonary function meter comprises a differential pressure sensor and a flow sensor, wherein the flow sensor is a hollow tube structure, and comprises an exhalation air inlet portion, a first cone portion, a throat portion and a second cone portion connected in sequence. The low pressure pressure tap is opened on the wall of the throat portion, and the first high pressure pressure port is opened on the exhalation air inlet or the first cone portion, and the first high pressure pressure port of the flow sensor and the positive pressure of the differential pressure sensor The end connection, the low pressure pressure port of the flow sensor is connected to the low pressure end of the differential pressure sensor. .
The pulmonary function meter according to claim 5, wherein the exhalation air inlet portion has a diameter larger than a throat portion, and the first tapered portion and the second tapered portion have a smaller diameter end connected to the throat portion.
The pulmonary function meter comprises a differential pressure sensor and a flow sensor, wherein the flow sensor is a hollow tube structure, and is mainly connected by an exhalation air inlet portion, a first cone portion, a throat portion and a second cone portion. The low pressure pressure port is opened on the pipe wall of the throat portion, and the first high pressure pressure port and the second high pressure pressure port are respectively opened on the pipe walls on both sides of the non-throat portion; the differential pressure sensor and the flow sensor The pressure port connection includes a first differential pressure sensor and a second differential pressure sensor.
The pulmonary function meter according to claim 7, wherein the first high pressure pressure port of the flow sensor is connected to the positive pressure end of the first differential pressure sensor, and the positive pressure of the second high pressure pressure port and the second differential pressure sensor The end connection, the low pressure end of the two differential pressure sensors are respectively connected to the low pressure pressure tapping port of the throat through the tee pipe.
The pulmonary function meter according to claim 7, further comprising an automatic determination system of two detection modes of breath detection and inspiratory detection.
A method of detecting lung function, comprising the following steps:

(1) providing the pulmonary function meter according to claims 7 to 9;

(2) The tester's mouth contains the front end of the expiratory air intake of the flow sensor, and exhales or inhales;

(3) reading the first differential pressure sensor and the second differential pressure sensor data;

(4) Judging whether the tester is performing exhalation or inhalation;

(5) If the judgment is an exhalation state, the lung function meter reads the data of the first differential pressure sensor; if the inhalation state is determined, the lung function meter takes the data of the second differential pressure sensor;

(6) In step 5, the lung function detection parameter of the tester is calculated according to the obtained data of the first differential pressure sensor or the data of the second differential pressure sensor.
The method for detecting lung function according to claim 10, wherein in the process of detecting continuous breathing gas in the pulmonary function meter, the determining method of the step (4) comprises: comparing the pressure difference values of the two differential pressure sensors to It is judged whether the tester performs exhalation or inhalation on the flow sensor.
Use of the flow sensor of any one of claims 1 to 9 in the preparation of a pulmonary function meter.