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

Abstract

The present invention relates to a kind of accumulative formula flow and take into account method of work, it is made up of two hydrostatic columns vertically communicated, the horizontal cylindrical one end of display transient flow flow has the gas outlet of upward opening, the other end has downwardly open air inlet, horizontal cylindrical internal tank has the piston with spring, piston has three small through hole, symmetrical centered by it; In display measurement, the vertical cylindrical vessel top of the accumulative gas flow of current time is gas outlet, and lower openings communicates with horizontal cylindrical container intracavity, has a lightweight bead in vertical cylindrical vessel. Set up the relation between piston pressure at two ends difference and gas instantaneous delivery, show the size of its instantaneous delivery by the size of spring deformation amount produced by pressure differential. Meanwhile, a certain proportion of gas promotes bead at the uniform velocity to rise through the inner chamber that communicates, and by the scale that rising displacement is corresponding, draws the integrated flow entering effusion meter gas. This design makes device be simplified, and improves its motility and reliability.

Description

A kind of accumulative formula flow takes into account method of work

Technical field

The present invention relates to a kind of accumulative formula effusion meter.

Background technology

Pulmonary function test is the important scope of examination of breast, lung disease and physiology of respiration clinically, is widely used in Respiratory Medicine, department of pediatrics, surgery, epidemiology and navigation aviation medicine etc. Traditional pulmonary function test (pft) instrument adopts differential pressure flowmeter mostly, the operation principle of differential pressure flowmeter is according to the differential pressure being installed in pipeline flow detection part and producing with fluid interaction, the physical dimension of known fluid condition and detection piece and pipeline carrys out calculated flow rate, and differential pressure flowmeter is made up of primary device (detection piece) and secondary device (differential pressure transmitter and flow displaying instrument). But conventional apparatus is in that to measure the instantaneous value of respiratory flow, it is impossible to measure the aggregate-value (i.e. lung volume paparmeter) of flow. In actual application, often not only to measure the instantaneous value of respiratory flow, also to measure patient and once exhale or the air capacity of air-breathing, as the important parameter checking lung capacity and lung compliance function.

Summary of the invention

The present invention be directed to existing pneumotachograph structure complicated, and instantaneous delivery can only be measured, and the problem that accumulative gas flow can not be measured, propose a kind of accumulative formula flow and take into account method of work, instantaneous delivery can be measured, the integrated flow of gas can be obtained again, and simplify the structure of device.

The technical scheme is that a kind of accumulative formula effusion meter, it is made up of two hydrostatic columns vertically communicated, the horizontal cylindrical one end of display transient flow flow has the gas outlet of upward opening, the other end has downwardly open air inlet, horizontal cylindrical internal tank has one section of spring, spring one end is fixed on culminating point in the pipe of this end of gas outlet, the other end is fixed on disc piston centre, piston diameter mates with horizontal cylindrical inside diameter of vessel, piston has three small through hole, centered by it symmetrical, scale is had above horizontal cylindrical container, in display measurement, the vertical cylindrical vessel top of the accumulative gas flow of current time is gas outlet, vertical cylindrical vessel lower openings communicates with horizontal cylindrical container intracavity, vertical cylindrical vessel has a lightweight bead, its diameter is less than the interior diameter of vertical cylindrical vessel, vertical cylindrical vessel lower openings, less than lightweight bead, has scale above vertical cylindrical vessel.

The method of work of described effusion meter, specifically includes following steps:

1) before air blowing starts, putting effusion meter on level table, due to the effect of gravity and spring, bead stops at the bottom of vertical cylindrical vessel, and piston is positioned at horizontal cylindrical container initial position, the position of original length when namely spring is by external force;

2) start to blow, along with air inlet gas flow q_vIncreasing by zero, piston pressurized is moved to the left gradually, and bead is suffered to buoyancy F₂Being not enough to overcome bead gravity, bead is transfixion still;

3) when air velocity progressively increases to certain value, buoyancy F suffered by bead₂Slightly larger than himself gravity, bead abruptly starts to move upward with certain acceleration, simultaneously thrust F suffered by piston₁Instantaneous slightly reducing, after one section of micro-displacement of spring resilience to the right, its position remains unchanged, when piston holding position is constant, now by piston from original position to the size of left dislocation, can drawing the instantaneous value of air inlet stream, piston to the relation between left dislocation size and instantaneous delivery is:

$\mathrm{\Δ}x=\frac{{\left(\frac{3{R_2}^2}{3{R_2}^2+({R_3}^2-{R_4}^2)}{q}_v\right)}^2*\mathrm{\ρ}}{2*{C_v}^2\×{\left(3{{\mathrm{\πR}}_1}^2\right)}^2\×\mathrm{\λ}}\mathrm{\π}({R_1}^2-3\×{R_2}^2)$

In formula: q_vFor entering the instantaneous delivery of gas from air inlet (5), unit is m³/ s; �� is the coefficient of elasticity of spring, and unit is m/N; �� x be piston from original position to the size of left dislocation, unit is m; �� is the density that air inlet enters gas, and unit is kg/m³; R₁For the internal face radius of horizontal cylindrical container, R₂For piston upper circular aperture radius, R₃For the radius of vertical hydrostatic column, R₄Radius for ball; C_vFor correction coefficient;

5) air inlet gas flow q is now kept_vConstant, namely with constant speed air inlet, bead maintenance at the uniform velocity rises, till when bead rises to its highest point, revised by the maximum displacement that bead is risen, its scale with entrance integrated flow one_to_one corresponding, the scale according to vertical cylindrical vessel, can draw the gas integrated flow Q entering device from entrance_v, the relation between bead rising displacement and the integrated flow of gas is:

$\mathrm{\Δ}s=\frac{(F_2-mg)e^{-\frac{k}{m}t}m}{k^2}+\frac{t}{k\×F_2}-\frac{t}{k\×mg}-\frac{m(F_2-mg)}{k^2}$

$F_2=0.5\×{\left(\frac{\frac{({R_3}^2-{R_4}^2)}{3{R_2}^2+({R_3}^2-{R_4}^2)}{q}_v}{C_v\×\mathrm{\π}({R_3}^2-{R_4}^2)}\right)}^2\mathrm{\ρ}\×{{\mathrm{\πR}}_4}^2$

Q_v=t �� q_v

In formula: �� s is bead rising displacement m; Q_vFor entering the integrated flow of gas from air inlet, unit is m³, q_vFor being calculated the instantaneous delivery entering gas from air inlet of gained by amount of piston displacement, unit is m³/ s; M is the quality of bead; Intermediate variable t is the time, and unit is s; The proportionality coefficient of its resistance and speed when k is bead low-speed motion;

5) if air-blowing quantity is excessive, bead will not continue to rising and reaches gas outlet, it was shown that user is exhaled and reached the requirement of test design standard, and the scale maximum scale of vertical cylindrical vessel is design normal flow;

6) last, air blowing terminates, and bead and piston return to initial position.

The beneficial effects of the present invention is: the accumulative formula flow of the present invention takes into account method of work, the relation between build-up pressure difference and gas flow, by adopting the size of spring deformation amount produced by pressure differential to show the size of its flow. At the uniform velocity risen by a certain proportion of gas push bead simultaneously, by the scale that rising displacement is corresponding, draw the flow entering gas. Not only make device be simplified, and improve the motility of system, reliability.

Accompanying drawing explanation

Fig. 1 is the accumulative formula effusion meter cross section structure schematic diagram of the present invention;

Fig. 2 is piston sectional view in the accumulative formula effusion meter of the present invention;

When Fig. 3 is air flow inlet 200mL/s of the present invention, calculate the speed cloud atlas of gained;

Fig. 4 is test speed of the present invention and time history.

Detailed description of the invention

Accumulative formula effusion meter cross section structure schematic diagram as shown in Figure 1, described effusion meter is sectioned schematic diagram by its axis, effusion meter is made up of two hydrostatic columns vertically communicated, there is the gas outlet 1 of upward opening horizontal cylindrical container 2 one end, the other end has downwardly open air inlet 5, horizontal cylindrical container 2 is internal one section of spring 3, spring one end is fixed on culminating point in the pipe of this end of gas outlet 1, the other end is fixed on disc piston 4 center, piston 4 diameter mates with horizontal cylindrical container 2 internal diameter, such as the profile that Fig. 2 is piston 4, piston 4 has three small through hole, centered by it symmetrical, corresponding scale is had above horizontal cylindrical container 2, in order to show transient flow flow,Vertical cylindrical vessel 7 top is gas outlet 6, lower openings communicates with horizontal cylindrical container 2 inner chamber, vertical cylindrical vessel 7 has a lightweight bead 8, its diameter is slightly less than the interior diameter of vertical cylindrical vessel 7, a small gap is had between the inwall of bead and vertical cylindrical vessel 7, spacing is 0.2mm, can there is the space effusion that small part of gas is passed through between bead 8 and vertical cylindrical vessel 7 wall, enter there being gas, when bead is blown afloat by air-flow, it is not directly contacted with between bead 8 and vertical cylindrical vessel 7 wall, corresponding scale is had above vertical cylindrical vessel 7, in order to show the accumulative gas flow of current time in measurement.

Operation principle:

1, this accumulative formula effusion meter measures flow and instantaneous velocity according to bernoulli equation and fluid continuity principle differential pressure method. Assume from air inlet 5 entrance enter air for can not press, Steady Flow, piston 4 left and right sides pressure differential deltap p can draw according to bernoulli equation:

$q_{v1}=C_v{A}_1\sqrt{2{\mathrm{\Δp}}_1/\mathrm{\ρ}}$

In formula: q_v1For the volume flow that gas is flowed out by piston 4, m³/ s; A₁For under duty, piston 4 aperture area, A₁=3 �� �� R₂ ², m², R₂For piston upper circular aperture radius; �� p₁For piston both sides average differential pressure, Pa; �� is the density entering gas, kg/m³; C_vFor correction coefficient.

In like manner can obtain the upper and lower both sides pressure differential deltap p of bead can draw according to classical bernoulli equation:

$q_{v2}=C_v{A}_2\sqrt{2{\mathrm{\Δp}}_2/\mathrm{\ρ}};$

The flow that gas is total is entered from air inlet 5 entrance:

q_v=q_v1+q_v2;

2, pressure to the left suffered by piston:

$F_1={\mathrm{\Δp}}_1\×\mathrm{\π}(R_1^2-3\×R_2^2)$

In formula: F₁Pressure to the left suffered by piston, N; �� p₁Poor for piston pressure at both sides, Pa; R₁For container 7 internal diameter radius, m; R₂For piston upper circular aperture radius, m.

Bead is suffered to buoyancy:

F₂=�� p₂���С�R₃ ²

In formula: F₂Buoyancy upwards suffered by bead, N; �� p₂Poor for the upper and lower pressure at both sides of bead, Pa; R₃For container 2 internal diameter radius, m.

3, above-mentioned each size is respectively as shown in table 1: R₁For the internal face radius of horizontal cylindrical container 2, R₂For piston upper circular aperture radius, R₃For the radius of vertical hydrostatic column, R₄For the radius 6.8 of ball, bead is in vertical hydrostatic column.

Table 1

Parameter	Size (mm)
		R1	8
R2	1
		R3	7
R4	6.8
		Cv	0.72

4, Calculation and Analysis of Force

When can be calculated inlet flow rate respectively 100mL/s, 200mL/s, 300mL/s, corresponding F₁��F₂Enter respectively shown in table 2 below. When Fig. 3 is air flow inlet 200mL/s, by the speed cloud atlas of numerical computations gained.

Table 2

Inlet flow rate (mL/s)	F1(N)	F2(N)
			100	0.012	0.007
200	0.038	0.021
			300	0.076	0.035

Specifically used step is as follows:

The first step: blow before starting, putting effusion meter on level table, due to the effect of gravity and spring, bead stops at the bottom of vertical cylindrical vessel 7 shown in Fig. 1, piston is positioned at horizontal cylindrical container 2 initial position, the position of original length when namely spring is not by external force.

Second step: along with air inlet 5 gas flow q_vIncreasing by zero, piston 4 pressurized is moved to the left gradually, but owing to vertical cylindrical vessel 7 bottom is less with the inlet flow rate that hydrostatic column 2 inner chamber communicates, bead is suffered to buoyancy F₂Being not enough to overcome bead gravity, air-flow passes through bead edge flow q_V2Being negligible, bead is transfixion still.

3rd step: when air velocity progressively increases to certain value, buoyancy F suffered by bead₂Slightly larger than himself gravity, bead abruptly starts to move upward with certain acceleration. Thrust F suffered by piston 4 simultaneously₁Instantaneous slightly reducing, after one section of micro-displacement of spring resilience to the right, its position remains unchanged.When piston holding position is constant, now by piston from original position to the size of left dislocation, the relation according to piston displacement Yu instantaneous delivery, it is converted into scale value, the instantaneous value of air inlet stream can be drawn by scale.

Piston to the relation between left dislocation size and instantaneous delivery is:

$\mathrm{\Δ}x=\frac{{\left(\frac{3{R_2}^2}{3{R_2}^2+({R_3}^2-{R_4}^2)}{q}_v\right)}^2*\mathrm{\ρ}}{2*{C_v}^2\×{\left(3{{\mathrm{\πR}}_1}^2\right)}^2\×\mathrm{\λ}}\mathrm{\π}({R_1}^2-3\×{R_2}^2)$

In formula: q_vFor entering the instantaneous delivery m of gas from air inlet³/ s; �� is the coefficient of elasticity of spring, m/N; �� x is that piston is from original position to the size m of left dislocation; �� is the density kg/m that air inlet enters gas³; R₁For the internal face radius of horizontal cylindrical container 2, R₂For piston upper circular aperture radius, R₃For the radius of vertical hydrostatic column, R₄Radius for ball; C_vFor correction coefficient.

Assume F₂From less than bead gravity, when increasing to suddenly 1.01 times of gravity, bead starts acceleration and moves upward, its acceleration:

$\frac{d^{2}s}{{\mathrm{dt}}^2}=\frac{F_2-mg}{m}---\left(1\right)$

After bead setting in motion, its acceleration is:

$\frac{d^{2}s}{{\mathrm{dt}}^2}=\frac{F_2-mg-f}{m}---\left(2\right)$

The quality m wherein taking bead is 2 grams, and s is that bead shifts up, and f is that bead moves upward and is subject to air drag, and owing to its speed is less, f size is directly proportional to speed, and its proportionality coefficient takes k=0.0018.

$f=k\frac{ds}{dt}---\left(3\right)$

Above equation being solved and after proper bead rising displacement is approximately 8mm, can start to be about 10mm/s with speed and at the uniform velocity move upward, its speed is with time relationship as shown in Figure 4.

4th step: now keep air inlet gas flow q_vConstant, namely with constant speed air inlet, bead maintenance at the uniform velocity rises. Till when bead rises to its highest point. Revised by the maximum displacement that bead is risen, it is possible to obtain and entrance integrated flow scale one to one, the scale according to vertical cylindrical vessel 7, the gas integrated flow Q entering device from entrance can be drawn_v. From total flow of the gas that air inlet 5 enters, because the position of piston can show that air inlet 5 enters the instantaneous delivery of gas, the displacement that bead at the uniform velocity rises can reflect the time of air blowing, and namely both products are survey the integrated flow once blown when breathing after revising. By the displacement size of piston, the instantaneous delivery q of piston can be obtained through_v1, by q fixed in operation principle_v1With q_v2Between relation, the instantaneous value of now inlet flow rate can be obtained.

Relation between bead rising displacement and the integrated flow of gas is:

$\mathrm{\Δ}s=\frac{(F_2-mg)e^{-\frac{k}{m}t}m}{k^2}+\frac{t}{k\×F_2}-\frac{t}{k\×mg}-\frac{m(F_2-mg)}{k^2}$

$F_2=0.5\×{\left(\frac{\frac{({R_3}^2-{R_4}^2)}{3{R_2}^2+({R_3}^2-{R_4}^2)}{q}_v}{C_v\×\mathrm{\π}({R_3}^2-{R_4}^2)}\right)}^2\mathrm{\ρ}\×{{\mathrm{\πR}}_4}^2$

Q_v=t �� q_v

In formula: �� s is bead rising displacement m; Q_vFor entering the integrated flow m of gas from air inlet³, q_vFor being calculated the instantaneous delivery m entering gas from air inlet of gained by amount of piston displacement³/ s; M is the quality of bead; Intermediate variable t is time s; The proportionality coefficient of its resistance and speed when k is bead low-speed motion.

If air-blowing quantity is excessive, owing to gas outlet 6 circle hole radius is less than the little radius of a ball, it will not continue to rise, it was shown that user is exhaled and reached the requirement of relevant criterion.

Finally, air blowing terminates, and bead and piston return to initial position.

The normal condition of ordinary people once exhale (vital capacity) be approximately about 2000mL, namely qualified. Such as the standard-required reached as user expiration, it is more weak that patient is likely to body constitution, or age-sex is different, and its requirement is likely 1200, it is also possible to be 1500. When bead rises to highest point, it is possible to by being 2000mL to being dimensioned such that now corresponding integrated flow, namely that different standard-requireds is all effective.

Claims (2)

1. an accumulative formula effusion meter, it is characterized in that, it is made up of two hydrostatic columns vertically communicated, there is the gas outlet (1) of upward opening horizontal cylindrical container (2) one end of display transient flow flow, the other end has downwardly open air inlet (5), horizontal cylindrical container (2) is internal one section of spring (3), spring one end is fixed on culminating point in the pipe of gas outlet (1) this end, the other end is fixed on disc piston (4) center, piston (4) diameter mates with horizontal cylindrical container (2) internal diameter, piston (4) has three small through hole, centered by it symmetrical, horizontal cylindrical container has scale above (2),In display measurement, vertical cylindrical vessel (7) top of the accumulative gas flow of current time is gas outlet (6), vertical cylindrical vessel (7) lower openings communicates with horizontal cylindrical container (2) inner chamber, vertical cylindrical vessel (7) has a lightweight bead (8), its diameter is less than the interior diameter of vertical cylindrical vessel (7), vertical cylindrical vessel (7) lower openings is less than lightweight bead (8), and vertical cylindrical vessel has scale above (7).

2. the method for work of effusion meter described in claim 1, it is characterised in that specifically include following steps:

1) before air blowing starts, put effusion meter on level table, effect due to gravity and spring, bead stops at the bottom of vertical cylindrical vessel (7), piston is positioned at horizontal cylindrical container (2) initial position, the position of original length when namely spring is not by external force;

2) start to blow, along with air inlet (5) gas flow q_vIncreasing by zero, piston (4) pressurized is moved to the left gradually, and bead is suffered to buoyancy F₂Being not enough to overcome bead gravity, bead is transfixion still;

3) when air velocity progressively increases to certain value, buoyancy F suffered by bead₂Slightly larger than himself gravity, bead abruptly starts to move upward with certain acceleration, simultaneously thrust F suffered by piston (4)₁Instantaneous slightly reducing, after one section of micro-displacement of spring resilience to the right, its position remains unchanged, when piston holding position is constant, now by piston from original position to the size of left dislocation, can drawing the instantaneous value of air inlet stream, piston to the relation between left dislocation size and instantaneous delivery is:

$\mathrm{\Δ}x=\frac{{\left(\frac{3{R_2}^2}{3{R_2}^2+({R_3}^2-{R_4}^2)}{q}_v\right)}^2*\mathrm{\ρ}}{2*{C_v}^2\×{\left(3{{\mathrm{\πR}}_1}^2\right)}^2\×\mathrm{\λ}}\mathrm{\π}({R_1}^2-3\×{R_2}^2)$

In formula: q_vFor entering the instantaneous delivery of gas from air inlet (5), unit is m³/ s; �� is the coefficient of elasticity of spring (3), and unit is m/N; �� x be piston (4) from original position to the size of left dislocation, unit is m; �� is the density that air inlet (5) enters gas, and unit is kg/m³; R₁For the internal face radius of horizontal cylindrical container (2), R₂For piston upper circular aperture radius, R₃For the radius of vertical hydrostatic column, R₄Radius for ball; C_vFor correction coefficient;

4) air inlet gas flow q is now kept_vConstant, namely with constant speed air inlet, bead maintenance at the uniform velocity rises, till when bead rises to its highest point, revised by the maximum displacement that bead is risen, its scale with entrance integrated flow one_to_one corresponding, the scale according to vertical cylindrical vessel (7), can draw the gas integrated flow Q entering device from entrance_v, the relation between bead rising displacement and the integrated flow of gas is:

$\mathrm{\Δ}s=\frac{(F_2-mg)e^{-\frac{k}{m}t}m}{k^2}+\frac{t}{k\×F_2}-\frac{t}{k\×mg}-\frac{m(F_2-mg)}{k^2}$

$F_2=0.5\×{\left(\frac{\frac{({R_3}^2-{R_4}^2)}{3{R_2}^2+({R_3}^2-{R_4}^2)}{q}_v}{C_v\×\mathrm{\π}({R_3}^2-{R_4}^2)}\right)}^2\mathrm{\ρ}\×{{\mathrm{\πR}}_4}^2$

Q_v=t �� q_v

In formula: �� s is bead rising displacement, and unit is m; Q_vFor entering the integrated flow of gas from air inlet (5), unit is m³, q_vFor being calculated the instantaneous delivery entering gas from air inlet (5) of gained by amount of piston displacement, unit is m³/ s; M is the quality of bead; Intermediate variable t is the time, and unit is s; The proportionality coefficient of its resistance and speed when k is bead low-speed motion;

5) if air-blowing quantity is excessive, bead will not continue to rising and reaches gas outlet (6), it was shown that user is exhaled and reached the requirement of test design standard, and the scale maximum scale of vertical cylindrical vessel (7) is design normal flow;

6) last, air blowing terminates, and bead and piston return to initial position.