CN104337521B - A kind of accumulative formula flow takes into account method of work - Google Patents

Abstract

The invention relates to an accumulative flowmeter and its working method, which is composed of two vertically connected cylindrical containers. The horizontal cylindrical container for displaying the instantaneous air flow has an air outlet opening upward at one end and an air inlet opening downward at the other end. There is a piston with a spring inside the horizontal cylindrical container, and there are three small through holes on the piston, which are center-symmetrically distributed; the top of the vertical cylindrical container showing the cumulative gas flow at the current moment during measurement is the gas outlet, and the lower opening is in line with the horizontal The inner cavity of the cylindrical container is connected, and there is a light ball in the vertical cylindrical container. Establish the relationship between the pressure difference at both ends of the piston and the instantaneous flow of gas, and display the instantaneous flow through the spring deformation generated by the pressure difference. At the same time, a certain proportion of gas passes through the connected inner cavity to push the ball up at a constant speed, and the cumulative flow rate of the gas entering the flowmeter is obtained through the scale corresponding to the rising displacement. This design simplifies the device and increases its flexibility and reliability.

Description

An accumulative flowmeter and its working method

technical field

The invention relates to an accumulative flowmeter.

Background technique

Pulmonary function test is an important clinical examination of chest and lung diseases and respiratory physiology, and is widely used in respiratory medicine, pediatrics, surgery, epidemiology, and navigation and aviation medicine. Most traditional lung function testing instruments use differential pressure flowmeters. The working principle of differential pressure flowmeters is based on the differential pressure generated by the interaction between the flow detection part installed in the pipeline and the fluid, the known fluid conditions and the relationship between the detection part and the pipeline. The geometric dimensions are used to calculate the flow rate. The differential pressure flowmeter consists of a primary device (detection piece) and a secondary device (differential pressure converter and flow display instrument). However, the traditional device can only measure the instantaneous value of the respiratory flow, but cannot measure the cumulative value of the flow (that is, the lung volume parameter). In practical applications, it is often necessary to measure not only the instantaneous value of respiratory flow, but also the volume of air that the patient exhales or inhales once, as an important parameter for checking lung volume and lung compliance function.

Contents of the invention

The present invention aims at the problem that the existing respiratory flowmeter has a complex structure and can only measure the instantaneous flow rate, but not the accumulated gas flow rate, and proposes an accumulative flowmeter and its working method, which can not only measure the instantaneous flow rate, but also can measure the accumulated gas flow rate. The cumulative flow of gas is obtained, and the structure of the device is simplified.

The technical solution of the present invention is: an accumulative flowmeter, which is composed of two vertically connected cylindrical containers, one end of the horizontal cylindrical container for displaying the instantaneous air flow has an upward-opening air outlet, and the other end has a downward-opening air inlet. Air port, there is a section of spring inside the horizontal cylindrical container, one end of the spring is fixed on the center vertex of the tube at the end of the air outlet, and the other end is fixed on the center of the disc-shaped piston, the diameter of the piston matches the inner diameter of the horizontal cylindrical container, and there are three small springs on the piston. Through holes, which are center-symmetrically distributed, with scales on the horizontal cylindrical container; the top of the vertical cylindrical container that displays the cumulative gas flow at the current moment during measurement is the gas outlet, and the lower opening of the vertical cylindrical container communicates with the inner cavity of the horizontal cylindrical container. There is a light ball in the vertical cylindrical container, the diameter of which is smaller than the inner diameter of the vertical cylindrical container, the lower opening of the vertical cylindrical container is smaller than the light ball, and there are scales on the vertical cylindrical container.

The working method of the flow meter specifically comprises the steps:

1) Before the blowing starts, place the flowmeter on the horizontal platform. Due to the action of gravity and spring, the ball stops at the bottom of the vertical cylindrical container, and the piston is at the initial position of the horizontal cylindrical container, that is, when the spring is not subjected to external force. the position of the original length;

2) Start to blow air, and as the gas flow _qv at the air inlet increases from zero, the piston gradually moves to the left under pressure, and the upward buoyancy force F ₂ on the ball is not enough to overcome the gravity of the ball, and the ball remains stationary ;

3) When the air velocity gradually increases to a certain value, the buoyancy force F ₂ on the ball is slightly greater than its own gravity, and the ball suddenly starts to move upward with a certain acceleration, and at the same time the thrust F ₁ on the piston decreases slightly instantaneously, and the spring After a small displacement of the right rebound, its position remains unchanged. When the piston maintains the same position, the instantaneous value of the airflow at the air inlet can be obtained by the displacement of the piston from the initial position to the left at this time, and the displacement of the piston to the left The relationship with the instantaneous flow is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; *</span>{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; \&pi;R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; \&times;</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>$

In the formula: q _v is the instantaneous flow rate of the gas entering from the air inlet (5), the unit is m ³ /s; λ is the elastic coefficient of the spring, the unit is m/N; Δx is the displacement of the piston from the initial position to the left , the unit is m; ρ is the density of the gas entering the air inlet, the unit is kg/m ³ ; R ₁ is the radius of the inner wall of the horizontal cylindrical container, R ₂ is the radius of the circular hole on the piston, and R ₃ is the vertical The radius of the cylindrical container, R ₄ is the radius of the ball; C _v is the correction coefficient;

5) At this time, keep the gas flow q _v at the air inlet constant, that is, inhale at a constant speed, and the ball keeps rising at a constant speed until the ball rises to its highest point. Correction, the scale can be one-to-one correspondence with the cumulative flow at the inlet. According to the scale of the vertical cylindrical container, the cumulative gas flow Q _v entering the device from the inlet, the relationship between the rising displacement of the ball and the cumulative flow of gas can be obtained for:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; t</span>}}\mathrm{<span\; class="notranslate">\; m</span>}}{{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\frac{\frac{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; \&times;</span>{{\mathrm{<span\; class="notranslate">\; \&pi;R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Q _v ＝t×q _v

In the formula: Δs is the rising displacement of the ball in m; Q _v is the cumulative flow of gas entering the gas inlet from the air inlet, in m ³ , and q _v is the instantaneous flow of gas entering the gas from the air inlet calculated from the displacement of the piston, in units of is m ³ /s; m is the mass of the ball; the intermediate variable t is time, and the unit is s; k is the proportional coefficient between the resistance and the speed of the ball when it moves at low speed;

5) If the blowing volume is too large, the ball will not continue to rise to reach the air outlet, indicating that the user's exhalation meets the requirements of the test design standard, and the maximum scale of the vertical cylindrical container is the design standard flow rate;

6) Finally, the blowing ends, and the ball and the piston return to their initial positions.

The beneficial effect of the present invention is that: the accumulative flowmeter and the working method of the present invention establish the relationship between the pressure difference and the gas flow, and display the flow by using the spring deformation generated by the pressure difference. At the same time, a certain proportion of gas is used to push the ball up at a constant speed, and the flow rate of the entering gas can be obtained through the scale corresponding to the rising displacement. It not only simplifies the device, but also improves the flexibility and reliability of the system.

Description of drawings

Fig. 1 is the schematic diagram of the sectional structure of the accumulative flowmeter of the present invention;

Fig. 2 is a sectional view of the piston in the accumulative flowmeter of the present invention;

Fig. 3 is when the airflow inlet of the present invention is 200mL/s, the calculated velocity nephogram;

Fig. 4 is a graph showing the relationship between test speed and time in the present invention.

detailed description

As shown in Figure 1, the schematic diagram of the cross-sectional structure of the cumulative flowmeter, the flowmeter is cut from the central axis, the flowmeter is composed of two cylindrical containers connected vertically, and one end of the horizontal cylindrical container 2 has an upwardly open air outlet 1. There is an air inlet 5 opening downward at the other end. There is a section of spring 3 inside the horizontal cylindrical container 2. One end of the spring is fixed on the center vertex of the tube at the end of the air outlet 1, and the other end is fixed on the center of the disc-shaped piston 4. The piston 4. The diameter matches the inner diameter of the horizontal cylindrical container 2. As shown in Figure 2, it is a cross-sectional view of the piston 4. There are three small through holes on the piston 4, which are symmetrically distributed around the center. There are corresponding scales on the horizontal cylindrical container 2 for Display the instantaneous air flow rate; the top of the vertical cylindrical container 7 is an air outlet 6, and the lower opening communicates with the inner cavity of the horizontal cylindrical container 2, and there is a light ball 8 in the vertical cylindrical container 7, whose diameter is slightly smaller than that of the vertical cylindrical container 7, there is a slight gap between the ball and the inner wall of the vertical cylindrical container 7, the distance is 0.2mm, and a small part of gas can escape through the gap between the small ball 8 and the wall of the vertical cylindrical container 7. When gas enters and the ball is blown up by the air flow, the ball 8 is not in direct contact with the wall of the vertical cylindrical container 7, and there is a corresponding scale on the vertical cylindrical container 7 to display the cumulative gas flow at the current moment during the measurement.

working principle:

1. The accumulative flowmeter is based on the Bernoulli equation and the principle of fluid continuity to measure the flow rate and instantaneous flow rate by the differential pressure method. Assuming that the air entering from the air inlet 5 is incompressible and steady flow, the pressure difference Δp on the left and right sides of the piston 4 can be obtained according to the Bernoulli equation:

${\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}$

In the formula: q _v1 is the volume flow rate of the gas flowing out through the piston 4, m ³ /s; A ₁ is the small hole area of the piston 4 in the working state, A ₁ =3π×R ₂ ² , m ² , and R ₂ is the top of the piston The radius of the small circular hole; Δp ₁ is the average pressure difference on both sides of the piston, Pa; ρ is the density of the incoming gas, kg/m ³ ; C _v is the correction coefficient.

In the same way, the pressure difference Δp on the upper and lower sides of the ball can be obtained according to the classic Bernoulli equation:

${\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; \&Delta;p</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}<span\; class="notranslate">\; ;</span>$

The total flow of gas entering the inlet from the air inlet 5:

q _v =q _v1 +q _v2 ;

2. Leftward pressure on the piston:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; \&Delta;p</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>$

In the formula: F ₁ is the leftward pressure on the piston, N; Δp ₁ is the pressure difference on both sides of the piston, Pa; R ₁ is the radius of the inner diameter of the container 7, m; R ₂ is the radius of the small circular hole on the piston, m.

The upward buoyancy force on the ball:

F ₂ =Δp ₂ ×π×R ₃ ²

In the formula: F ₂ is the upward buoyancy force on the ball, N; Δp ₂ is the pressure difference between the upper and lower sides of the ball, Pa; R ₃ is the inner radius of the container 2, m.

3. The above-mentioned dimensions are shown in Table 1: R ₁ is the radius of the inner wall of the horizontal cylindrical container 2, R ₂ is the radius of the small circular hole on the piston, R ₃ is the radius of the vertical cylindrical container, and R ₄ is The radius of the ball is 6.8, and the ball is in a vertical cylindrical container.

Table 1

parameter Size (mm) R ₁ 8 R ₂ 1 R ₃ 7 R ₄ 6.8 C _v 0.72

4. Force analysis and calculation

When the calculated inlet flows are 100mL/s, 200mL/s, and 300mL/s, the corresponding F ₁ and F ₂ are shown in Table 2 below. Fig. 3 is the velocity contour obtained by numerical calculation when the airflow inlet is 200mL/s.

Table 2

Inlet flow(mL/s) F ₁ (N) F ₂ (N) 100 0.012 0.007 200 0.038 0.021 300 0.076 0.035

The specific steps are as follows:

Step 1: Before blowing air, place the flowmeter on the horizontal platform. Due to the action of gravity and spring, the ball stops at the bottom of the vertical cylindrical container 7 shown in Figure 1, and the piston is located at the initial position of the horizontal cylindrical container 2. , that is, the position of the original length of the spring when no external force is applied.

Step 2: As the gas flow q _v of the air inlet 5 increases from zero, the piston 4 gradually moves to the left under pressure, but the inlet flow rate between the lower part of the vertical cylindrical container 7 and the inner cavity of the cylindrical container 2 is relatively small , the upward buoyancy force F ₂ on the ball is not enough to overcome the gravity of the ball, the flow rate q _V2 of the air flow through the edge of the ball can be ignored, and the ball remains still.

Step 3: When the air velocity gradually increases to a certain value, the buoyancy force F ₂ on the ball is slightly greater than its own gravity, and the ball suddenly starts to move upward with a certain acceleration. Simultaneously, the thrust F ₁ suffered by the piston 4 decreases slightly instantaneously, and after the spring rebounds to the right for a small displacement, its position remains unchanged. When the position of the piston remains unchanged, the displacement of the piston from the initial position to the left at this time is converted into a scale value according to the relationship between the piston displacement and the instantaneous flow rate, and the instantaneous value of the airflow at the air inlet can be obtained through the scale.

The relationship between the displacement of the piston to the left and the instantaneous flow rate is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; *</span>{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; \&pi;R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; \&times;</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>$

In the formula: q _v is the instantaneous flow rate m ³ /s of the gas entering from the air inlet; λ is the elastic coefficient of the spring, m/N; Δx is the displacement m of the piston from the initial position to the left; The density of gas kg/m ³ ; R ₁ is the radius of the inner wall of the horizontal cylindrical container 2, R ₂ is the radius of the circular hole above the piston, R ₃ is the radius of the vertical cylindrical container, and R ₄ is the radius of the ball; C _v is the correction coefficient.

Assuming that F ₂ suddenly increases from less than the gravity of the ball to 1.01 times the gravity, the ball starts to accelerate upwards, and its acceleration is:

$\frac{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; the\; s</span>}}{{\mathrm{<span\; class="notranslate">\; dt</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

After the ball starts to move, its acceleration is:

$\frac{{\mathrm{<span\; class="notranslate">\; d</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; the\; s</span>}}{{\mathrm{<span\; class="notranslate">\; dt</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; f</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Wherein, the mass m of the ball is taken as 2 grams, s is the upward displacement of the ball, and f is the air resistance of the upward movement of the ball. Because its speed is small, the size of f is proportional to the speed, and its proportional coefficient is taken as k=0.0018.

$\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; k</span>}\frac{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}}{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Solving the above equations, it can be obtained that after the upward displacement of the ball is about 8mm, it starts to move upward at a constant speed of about 10mm/s, and the relationship between the speed and time is shown in Figure 4.

Step 4: At this time, keep the gas flow q _v at the air inlet unchanged, that is, inhale at a constant speed, and the ball keeps rising at a constant speed. until the ball rises to its highest point. By correcting the maximum displacement of the rising ball, the scale corresponding to the cumulative flow at the inlet can be obtained. According to the scale of the vertical cylindrical container 7, the cumulative flow _Qv of gas entering the device from the inlet can be obtained. The total flow rate of the gas entering from the air inlet 5, because the position of the piston can obtain the instantaneous flow rate of the gas entering the air inlet 5, and the displacement of the ball rising at a constant speed can reflect the blowing time, and the product of the two has been corrected After that, it is to measure the cumulative flow rate of one blow during breathing. Through the displacement of the piston, the instantaneous flow q _v1 passing through the piston can be obtained, and the instantaneous value of the inlet flow at this time can be obtained through the relationship between q _v1 and q _v2 determined in the working principle.

The relationship between the rising displacement of the ball and the cumulative flow of gas is:

$\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; t</span>}}\mathrm{<span\; class="notranslate">\; m</span>}}{{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\frac{\frac{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; \&times;</span>{{\mathrm{<span\; class="notranslate">\; \&pi;R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Q _v ＝t×q _v

In the formula: Δs is the rising displacement of the ball m; Q _v is the cumulative flow m ³ of the gas entering from the air inlet, and q _v is the instantaneous flow m ³ /s of the gas entering the air from the air inlet calculated from the displacement of the piston; m is the mass of the ball; the intermediate variable t is the time s; k is the proportional coefficient between the resistance and the speed of the ball when it moves at a low speed.

If the air blowing volume is too large, it will not continue to rise because the radius of the air outlet 6 circular holes is less than the radius of the bead, indicating that the user's exhalation meets the requirements of the relevant standards.

Finally, the blowing ends, and the ball and the piston return to their initial positions.

The normal condition of an ordinary person is to exhale (vital capacity) at one time, which is about 2000mL, which is qualified. For example, as the standard requirement for the user to exhale, the patient may have a weak constitution, or the age and sex are different, and the requirement may be 1200 or 1500. When the ball rises to the highest point, the corresponding cumulative flow rate at this time can be 2000mL through the design of the size, which is effective for different standard requirements.

Claims (2)

1. A cumulative flowmeter, characterized in that it is made up of two cylindrical containers vertically connected, and the horizontal cylindrical container (2) showing instantaneous air flow has an upwardly open air outlet (1) at one end, and a gas outlet (1) at the other end. The air inlet (5) of opening downwards has a section of spring (3) inside the horizontal cylindrical container (2), and one end of the spring is fixed on the center apex of the tube at the end of the air outlet (1), and the other end is fixed on the disc-shaped piston ( 4) Center, the diameter of the piston (4) matches the inner diameter of the horizontal cylindrical container (2), and there are three small through holes on the piston (4), which are symmetrically distributed around the center, and there are scales on the horizontal cylindrical container (2); The top of the vertical cylindrical container (7) for accumulative gas flow at the current moment in the measurement is the gas outlet (6), and the lower opening of the vertical cylindrical container (7) communicates with the inner cavity of the horizontal cylindrical container (2). 7) there is a lightweight pellet (8), its diameter is less than the inner diameter of the vertical cylindrical container (7), the bottom opening of the vertical cylindrical container (7) is smaller than the lightweight pellet (8), the vertical cylindrical container (7) ) with graduations on it. 2. the working method of the described flowmeter of claim 1, is characterized in that, specifically comprises the steps: 1) Before blowing, place the flowmeter on the horizontal platform. Due to the action of gravity and spring, the ball stops at the bottom of the vertical cylindrical container (7), and the piston is located at the initial position of the horizontal cylindrical container (2), that is The position of the original length of the spring when no external force is applied; 2) Start to blow air, as the gas flow q _v of the air inlet (5) increases from zero, the piston (4) gradually moves to the left under pressure, and the upward buoyancy force F ₂ on the ball is not enough to overcome the gravity of the ball, The ball remains still; 3) When the air velocity gradually increases to a certain value, the buoyancy F ₂ on the ball is slightly greater than its own gravity, and the ball suddenly starts to move upward with a certain acceleration, and at the same time, the thrust F ₁ on the piston (4) decreases slightly instantaneously , after the spring rebounds to the right for a small displacement, its position remains unchanged. When the piston maintains the same position, the instantaneous value of the airflow at the air inlet can be obtained from the displacement of the piston from the initial position to the left. The relationship between the magnitude of the left displacement and the instantaneous flow rate is: $\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; =</span>\frac{{<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; \&rho;</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; *</span>{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; \&pi;R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; \&times;</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>$ In the formula: q _v is the instantaneous flow rate of gas entering from the air inlet (5), in m ³ /s; λ is the elastic coefficient of the spring (3), in m/N; The size of the displacement to the left of the position, the unit is m; ρ is the density of the gas entering the air inlet (5), and the unit is kg/m ³ ; R ₁ is the radius of the inner wall of the horizontal cylindrical container (2), and R ₂ is the piston The radius of the circular hole above, R ₃ is the radius of the vertical cylindrical container, R ₄ is the radius of the ball; C _v is the correction coefficient; 4) At this time, keep the gas flow q _v at the air inlet constant, that is, inhale at a constant speed, and the ball keeps rising at a constant speed until the ball rises to its highest point. Correction, the scale can correspond to the cumulative flow at the inlet one by one. According to the scale of the vertical cylindrical container (7), the cumulative gas flow _Qv entering the device from the inlet, the relationship between the rising displacement of the ball and the cumulative flow of gas can be obtained. The relationship between is: $\mathrm{<span\; class="notranslate">\; \&Delta;</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; k</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}}\mathrm{<span\; class="notranslate">\; t</span>}}\mathrm{<span\; class="notranslate">\; m</span>}}{{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; t</span>}}{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}}<span\; class="notranslate">\; -</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; g</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; k</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}$ ${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0.5</span>}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\frac{\frac{<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 3</span>}{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; q</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; v</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; \&times;</span>{{\mathrm{<span\; class="notranslate">\; \&pi;R</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$ Q _v ＝t×q _v In the formula: Δs is the rising displacement of the ball, the unit is m; Q _v is the cumulative flow rate of the gas entering from the air inlet (5), the unit is m ³ , q _v is the calculated displacement of the piston from the air inlet ( 5) The instantaneous flow rate of the entering gas, the unit is m ³ /s; m is the mass of the ball; the intermediate variable t is time, the unit is s; k is the proportional coefficient between the resistance and the speed of the ball when it moves at a low speed; 5) If the blowing volume is too large, the ball will not continue to rise to the air outlet (6), indicating that the user's exhalation meets the requirements of the test design standard, and the maximum scale of the vertical cylindrical container (7) is the design standard flow rate; 6) Finally, the blowing ends, and the ball and the piston return to their initial positions.