JP2018201750A - Expired air measuring device - Google Patents

Abstract

To enhance measuring accuracy of expired air.SOLUTION: A flow controller 6 according to the present invention comprises: a body case 19 comprising an inflow port 20 into which expired air flows, and an outflow port 21 from which the expired air flows; a partition wall 24 for partitioning the inside of the body case 19 into an expired air inflow space 22 on the side of the inflow port 20 and an expired outflow space 23 on the side of the outflow port 21; a circular vent port 25 provided in the partition wall 24 to allow passage of the expired air; and a truncated cone-shaped regulating valve 26 slidably arranged in the vent port 25. A side surface of the truncated cone-shaped regulating valve 26 is contracted inward.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an exhalation measuring device used when performing asthma detection, lung function detection, and the like, for example.

  A conventional exhalation measuring device includes a measuring device main body into which exhaled air is blown, a flow regulator for adjusting exhaled air blown into the measuring device main body to a predetermined flow rate, and a chamber in which exhaled gas flowing out from the flow regulator is temporarily stored. A pump for supplying exhaled gas stored in the chamber to the measuring unit, a control unit for controlling the operation of the flow regulator, and a first pressure sensor connected to the inflow side of the flow regulator And a second pressure sensor connected to the exhalation side of the exhalation flow of the flow regulator.

  The control unit measures the pressure on the inflow side and the pressure on the outflow side of the flow rate regulator using two pressure sensors. Based on the pressure difference, the flow rate regulator adjusts the exhalation to a predetermined flow rate, and the adjusted exhalation is temporarily stored in the chamber.

  Thereafter, when exhaled air in the chamber is sent to the measurement unit, the concentration of nitric oxide contained in the exhaled air is detected (for example, Patent Document 1 below).

JP 2005-538819 A

  The problem in the conventional example is to improve the measurement accuracy of exhalation.

  That is, the expiration measuring apparatus adjusts expiration to a predetermined flow rate using a flow rate regulator. In this flow regulator, for example, by moving a conical regulating valve in the vent through which exhalation passes, the area of the gap between the vent and the regulating valve (the minimum area of the exhalation flow path, hereinafter also referred to as the gap area) , Thereby adjusting the expiration to a predetermined flow rate.

  Specifically, when it is desired to adjust the expiration to a predetermined flow rate, the pressure difference between the inflow side and the outflow side of the flow rate regulator is measured. It is known that the reciprocal of this pressure difference is proportional to the square of the gap area when the exhalation flow rate is constant. In addition, the exhalation measuring device has a relation between the square of the gap area and the amount of movement of the regulating valve, for example, as a relational expression representing a proportionality.

  For this reason, the square of the gap area is obtained from the pressure difference, and the amount of movement of the regulating valve (position of the regulating valve) is obtained from the square of the gap area and the relational expression.

  However, since the regulating valve has a conical shape, the square of the gap area is not proportional to the amount of movement of the regulating valve. For this reason, if a relational expression representing proportionality is used, an error occurs in the amount of movement of the regulating valve that is obtained. Therefore, an error occurs in the adjustment of the exhalation flow rate, and the measurement accuracy of the exhalation thereafter is lowered.

  In view of this, the present invention has an object to increase the measurement accuracy of exhalation.

  In order to achieve this object, an exhalation measuring device of the present invention includes a measuring device main body into which exhaled air is blown, a flow rate regulator that adjusts the exhaled air blown into the measuring device main body to a predetermined flow rate, and an outflow from the flow rate regulator. A chamber in which exhaled breath is temporarily stored, a pump that supplies the exhaled breath stored in the chamber to the measurement unit, a control unit that controls the operation of the flow regulator, and an inflow side of the flow regulator A first pressure sensor, and a second pressure sensor connected to the exhalation flow side of the flow regulator. The flow regulator includes a main body case having an inflow port for exhalation and an outflow port for exhalation, and a dividing wall that divides the main body case into the exhalation inflow space on the inflow port side and the exhalation outflow space on the outflow port side And a circular ventilation hole provided on the dividing wall for allowing exhalation to pass through, and a frustoconical adjustment valve slidably disposed in the ventilation hole. The frustum-shaped regulating valve has a side surface reduced inward.

  This achieves the intended purpose.

  In the flow regulator according to the present invention, a truncated cone-shaped regulating valve is disposed in a vent hole through which exhalation passes. The truncated cone-shaped regulating valve has a side surface reduced inward. That is, the side surface of the regulating valve is reduced inward so that the square value of the minimum area of the exhalation flow path is proportional to the amount of movement of the regulating valve.

  Therefore, when it is desired to adjust the exhalation to a predetermined flow rate, first, the pressure difference between the inflow side and the outflow side of the flow rate regulator is measured, and then the square of the gap area is obtained from this pressure difference.

  Further, the amount of movement of the regulating valve is obtained from a relational expression representing the square of the gap area and the proportionality.

  At this time, since the side surface of the regulating valve is reduced inward, the square of the gap area is proportional to the amount of movement of the regulating valve. Therefore, when a relational expression representing proportionality is used, the amount of movement of the regulating valve can be obtained appropriately.

  As a result, the flow rate of exhalation can be adjusted appropriately, and the measurement accuracy of exhalation can be improved.

1 is a perspective view of an exhalation measuring device according to Embodiment 1 of the present invention. FIG. 2 is a control block diagram of the breath measurement device of FIG. 1. Sectional drawing of the flow regulator of FIG. The perspective view of the principal part of FIG. The expanded sectional view of A part of FIG. The expanded sectional view of the B section of FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows an exhalation measuring device 1 used when performing asthma detection, lung function detection, and the like.

  The exhalation measuring device 1 measures, for example, the amount of nitric oxide (concentration of exhaled nitric oxide) contained in exhaled breath, and a handle portion 2 that sucks and inhales exhaled air via a handle tube 3. It is connected to the measuring device body 4.

  Here, when the user puts a mouth into the exhalation mouth 5 of the handle part 2 and performs inhalation, the air is taken into the handle part 2 and passes through a filter (not shown) in the handle part 2, and the filter uses the filter. The air from which nitric oxide has been removed is taken into the user's lungs. From here, when the user blows exhalation into the exhalation port 5, the exhaled exhalation passes through the handle tube 3 and is blown into the measuring device main body 4 of FIG. 1.

  FIG. 2 is a control block diagram of the measurement apparatus main body 4.

  In the measuring device main body 4, a flow rate regulator 6 is provided for adjusting the exhaled breath to a predetermined flow rate (the amount of exhaled gas flowing per unit time). This flow regulator 6 has an inflow side into which exhalation flows and an outflow side from which exhalation flows out. A pressure sensor 7 is connected to the inflow side and a pressure sensor 8 is connected to the outflow side. The pressure sensor 7 measures the pressure of exhalation on the inflow side of the flow regulator 6, and the pressure sensor 8 measures the pressure of exhalation on the outflow side of the flow regulator 6. Using the values of these two pressure sensors, the flow rate adjuster 6 adjusts the flow rate of exhalation to a predetermined value. The flow regulator 6 will be described in detail later.

  The exhaled air whose flow rate has been adjusted by the flow rate regulator 6 is sent to the chamber 9, and the exhaled air is temporarily stored in the chamber 9.

  At the time of measurement, the exhaled air stored in the chamber 9 is drawn to the pump 12 via the input gas switch 10 and the flow rate detector 11 and sent to the measuring unit 13.

  The flow rate adjuster 6, the pressure sensor 7, the pressure sensor 8, the input gas switch 10, the flow rate detector 11, the pump 12, and the measurement unit 13 are electrically connected to the control unit 14. Further, a display unit 15, a power switch 16, and a memory 17 are electrically connected to the control unit 14. The control unit 14 controls each connected unit.

  Various control programs used by the control unit 14 are stored in the memory 17.

  The input gas switch 10 is connected to a zero gas generator 18 that removes nitrogen monoxide from the air.

  The basic exhalation measurement operation will be described below.

  In addition, it demonstrates from the state in which the exhaled breath which was blown in is stored in the chamber 9. FIG.

  In the measurement of exhalation, first, the controller 14 uses the pump 12 to supply the exhaled gas stored in the chamber 9 to the measuring unit 13 at a predetermined flow rate via the input gas switch 10 and the flow rate detector 11. To do. And if the measurement part 13 measures nitric oxide in the expiration, the actual value of the expiration will be calculated | required.

  Next, the control unit 14 switches the input gas switch 10 from the chamber 9 side to the zero gas generator 18 side. Then, when the air in the measurement environment is passed through the zero gas generator 18 using the pump 12, nitric oxide is removed from the air. The air from which the nitric oxide has been removed is supplied to the measurement unit 13 via the input gas switch 10. When the measurement unit 13 measures air, a reference value is determined.

  Thereafter, when the control unit 14 compares the measured value of the exhalation with the reference value, the amount of nitric oxide contained in the exhalation is calculated, and the value is displayed on the display unit 15, for example, “15 ppb”. This represents that nitric oxide was detected at a rate of 15.1 billion relative to exhalation.

  With the above description, when the basic configuration and operation are understood, the characteristic points of this embodiment will be described below.

  The greatest feature point of the present embodiment is that the flow rate regulator 6 in FIG. 2 that adjusts the exhaled breath to a predetermined flow rate (the amount of exhaled gas flowing per unit time) increases the adjustment accuracy of the flow rate of the exhaled air. Then, the measurement accuracy of exhaled breath was improved.

  The flow regulator 6 will be described in detail below with reference to FIGS.

  FIG. 3 is a cross-sectional view of the flow regulator 6, and the main body case 19 of the flow regulator 6 includes an inlet 20 through which exhaled air flows on the inflow side. Further, an outflow port 21 through which exhaled gas flows out is provided on the side from which exhaled gas flows out.

  A partition wall 24 that divides the inside of the main body case 19 into an exhalation inflow space 22 on the inflow port 20 side and an exhalation outflow space 23 on the outflow port 21 side is provided inside the main body case 19. A circular vent 25 is provided at the center of the dividing wall 24.

  For this reason, exhaled air that has flowed into the exhalation inflow space 22 from the inflow port 20 enters the exhalation outflow space 23 through the vent 25 and flows out from the outflow port 21.

  An adjustment valve 26 formed in a substantially truncated cone shape is slidably disposed in the vent 25 through which exhalation passes. The truncated cone is a truncated cone having a circle as a bottom surface, and is a three-dimensional figure obtained by cutting the cone along a plane parallel to the bottom surface and excluding a small cone portion.

  For this reason, exhaled air passes through the gap between the vent 25 and the regulating valve 26. In actual adjustment, the pressure difference between the pressures detected by the pressure sensor 7 and the pressure sensor 8 is obtained, and the adjustment valve 26 is slid in accordance with the pressure difference to change the area of the gap, so that the flow rate of the exhalation Adjust so that becomes constant. Thereby, even if the pressure of the exhalation which a user blows in changes and the pressure of the inflow side of the flow regulator 6 changes, the flow rate of the exhalation becomes constant.

  The operation of the regulating valve 26 will be described in detail later.

  A lid 27 for closing the vent hole 25 is provided on one end side (left side in FIG. 3) of the regulating valve 26. Further, a cylindrical rod body 28 shown in FIG. 4 is provided on the other end side (the right side in FIG. 3) of the regulating valve 26. Further, the flow rate adjuster 6 is provided with a disk-shaped cam 29 that is opposed to the end portion on the other end side of the rod body 28 and slides the rod body 28. A stepping motor (not shown) is connected to the cam shaft 29a of the cam 29 via a gear (not shown). This stepping motor is connected to the control unit 14 in FIG.

  Then, when the control unit 14 drives the stepping motor, the rotational force is transmitted to the cam 29. The cam 29 converts the rotational motion into a linear motion of the rod body 28 and slides the rod body 28 in the axial direction. As a result, the regulating valve 26 on one end side of the rod body 28 slides in the vent hole 25. That is, the drive mechanism of the adjusting valve 26 is configured by the cam 29, the gear, and the stepping motor.

  The rod body 28 is biased by the spring 30 to the cam 29 side (the other end side) via a spring receiver 31 provided on the rod body 28.

  The spring 30 is separated from the exhalation outflow space 23 by a rubber separation membrane 32, and exhalation in the exhalation outflow space 23 does not enter the spring 30 side. The exhaled air in the exhaled outflow space 23 flows out of the exhaled outflow space 23 from the outflow port 21.

  An annular cover (lid body) 33 made of rubber (an example of an elastic body) is provided on the vent 27 side of the lid 27 of the regulating valve 26, and this cover 33 is provided around the vent hole 25. The vent hole 25 is covered with the lid 27 by contacting the annular wall 34 (see FIG. 5). In this state, exhaled air cannot pass through the vent hole 25.

  Hereinafter, the configuration and operation of the regulating valve 26 will be described.

  FIG. 5 is an enlarged view of portion A (partition wall 24 portion) of FIG.

  The dividing wall 24 is provided with a vent 25, and an adjusting valve 26 formed in a substantially truncated cone shape is slidably disposed in the vent 25.

  The regulating valve 26 has a bottom surface 35 of the truncated cone on one end side (left side in FIG. 5) and an upper surface 36 of the truncated cone on the other end side (right side in FIG. 4). Further, the distance from the bottom surface 35 to the top surface 36 is the height L1.

  One end side (bottom surface 35 side) of the regulating valve 26 is disposed in the exhalation inflow space 22, and the other end side (upper surface 36 side) is disposed in the exhalation outflow space 23. That is, the regulating valve 26 is disposed so as to penetrate through the vent 25, and the side surface of the regulating valve 26 is disposed so as to face the inner periphery of the vent 25. Further, the central axis of the regulating valve 26 passes through the center of the vent hole 25.

  For this reason, the regulating valve 26 slides along the center axis of the regulating valve 26 on the center of the vent hole 25.

  FIG. 6 is a view of the portion B in FIG. 5 as viewed from the side of the exhalation inflow space 22, and shows the positional relationship between the vent 25 and the regulating valve 26. The portion B is a portion where the vent 25 has the smallest diameter in the depth direction of the vent 25 (from the left side to the right side in FIG. 5 and from one end side to the other end side).

  As can be understood from FIG. 6, exhaled air passes through a gap 37 formed by the vent 25 and the regulating valve 26. The area of the gap 37 is determined by the position of the adjustment valve 26 with respect to the vent hole 25.

  More specifically, in FIG. 5, if the adjustment valve 26 is moved to one end side (left side in FIG. 5), the cross-sectional area of the adjustment valve 26 in FIG. 6 decreases and the gap 37 increases. That is, the flow rate of exhalation increases. On the contrary, in FIG. 5, if the regulating valve 26 is moved to the other end side (the right side in FIG. 5), the sectional area of the regulating valve 26 in FIG. 6 is increased, and the gap 37 is reduced. That is, the flow rate of expiration decreases.

  Thus, by moving (sliding) the regulating valve 26 in the vent 25, the minimum area of the exhalation flow path (the area of the gap 37, hereinafter also referred to as the gap area) is changed. Is adjusted to a predetermined flow rate.

  Specifically, when it is desired to adjust the exhalation to a predetermined flow rate, the control unit 14 uses the pressure sensor 7 to measure the pressure on the inflow side of the flow rate regulator 6 and uses the pressure sensor 8 to adjust the pressure on the outflow side. Measure and obtain the pressure difference between the inflow side and the outflow side of the flow rate regulator 6.

  It is known that the reciprocal of this pressure difference is proportional to the square of the gap area when the exhalation flow rate is constant. A relational expression A representing the proportional relation is stored in the memory 17.

  Further, the relationship between the square value of the gap area and the amount of movement of the regulating valve 26 is examined in advance, and a relational expression B representing the relationship is stored in the memory 17. Note that the relational expression B is a relational expression representing proportionality for the sake of simplification of calculation processing.

  Therefore, the control unit 14 represents the reciprocal of the pressure difference, the relational expression A that represents the relationship between the reciprocal of the pressure difference and the square of the gap area, and the relationship between the square of the gap area and the amount of movement of the adjustment valve 26. Using the relational expression B, the amount of movement of the regulating valve 26 (position of the regulating valve 26) is obtained.

  And if the control part 14 moves the adjustment valve 26 of the flow regulator 6 to the calculated | required position, the flow volume of expiration will be adjusted.

  In this way, the flow rate of exhalation is adjusted. If the regulating valve 26 has a conical shape, the square of the gap area and the amount of movement of the regulating valve 26 are not proportional. For this reason, if the relational expression B representing proportionality is used, an error occurs in the amount of movement of the regulating valve 26 that is obtained.

  Therefore, in the flow rate regulator 6 according to the present embodiment, as shown in FIG. 5, the regulating valve 26 has a substantially truncated cone shape, but its side surface is reduced inward. That is, the side surface of the regulating valve 26 is reduced inward so that the square value of the minimum area of the flow path is proportional to the movement amount of the regulating valve 26.

  In FIG. 5, the dotted line 38 is a line that linearly connects the outermost side of the bottom surface 35 and the outermost side of the upper surface 36 in the axial section of the regulating valve 26. That is, the dotted line 38 represents the side surface of the truncated cone formed by the bottom surface 35, the top surface 36, and the height L1.

  Further, the side surface of the regulating valve 26 is reduced toward the inner side (center axis side) from the bottom surface 35 to the upper surface 36 on the entire circumference of the side surface. That is, the side surface from the bottom surface 35 to the upper surface 36 is formed on the innermost side of the outermost side of the bottom surface 35 and the dotted line 38 that linearly connects the outermost side of the upper surface 36.

  Further, the side surface of the regulating valve 26 is such that the vicinity of the intermediate portion between the bottom surface 35 and the top surface 36 is reduced more inward than the bottom surface 35 and the top surface 36. That is, in the regulating valve 26, the side surface from the bottom surface 35 to the top surface 36 of the truncated cone is formed in a state where the central portion is slightly recessed.

  Furthermore, the entire side surface of the side surface of the regulating valve 26 is reduced inward. That is, the entire side surface of the truncated cone is reduced toward the inner side.

  Therefore, when it is desired to adjust the exhalation to a predetermined flow rate, the control unit 14 first measures the pressure difference between the inflow side and the outflow side of the flow rate regulator 6 using the pressure sensor 7 and the pressure sensor 8 as described above. Next, the square of the gap area is obtained from this pressure difference.

  Furthermore, the control part 14 calculates | requires the moving amount | distance of the regulating valve 26 from the square of a clearance area, and the relational expression B showing a proportionality.

  At this time, since the side surface of the regulating valve 26 is reduced inward, the square of the gap area is proportional to the amount of movement of the regulating valve 26. Therefore, when the relational expression B representing proportionality is used, the amount of movement of the regulating valve 26 can be obtained appropriately.

  As a result, the flow rate of exhalation can be adjusted appropriately, and the measurement accuracy of exhalation can be improved.

  Further, as shown in FIG. 3, the cam 29 for sliding the adjustment valve 26 has a so-called plate cam (disc cam) shape, and the control unit 14 rotates the cam 29 using a drive mechanism. The rod body 28 is configured to slide a predetermined distance.

  For this reason, since the regulating valve 26 on one end side of the rod body 28 can be appropriately slid within the vent hole 25, the exhalation adjusting accuracy can be increased.

  Furthermore, as shown in FIG. 2, the breath measurement apparatus 1 has the pressure sensor 7 connected to the breath inflow space 22 through the connection hole 39 (FIG. 3) and the breath through the connection hole 40 (FIG. 3). A pressure sensor 8 connected to the outflow space 23 is included. Based on the outputs of the two pressure sensors 7 and 8, the control unit 14 controls the movement of the cam 29.

  More specifically, when the outputs of the pressure sensor 7 and the pressure sensor 8 are sent to the control unit 14, the control unit 14 obtains a pressure difference between the two pressure sensors, and moves the cam 29 in accordance with the pressure difference. .

  For this reason, since the regulating valve 26 can be moved to an appropriate position in the vent 25 with respect to the vent 25, it is easy to adjust the flow rate of the exhaled air that increases or decreases in direct proportion to the moving amount of the regulating valve 26. Thus, exhalation adjustment accuracy can be increased.

  The present invention is expected to be utilized in an exhalation measuring apparatus used when performing asthma detection, lung function detection, and the like.

DESCRIPTION OF SYMBOLS 1 Exhalation measuring apparatus 2 Handle part 3 Handle tube 4 Measuring apparatus main body 5 Expiratory port 6 Flow rate regulator 7 Pressure sensor 8 Pressure sensor 9 Chamber 10 Input gas switch 11 Flow detector 12 Pump 13 Measuring part 14 Control part 15 Display part 16 Power switch 17 Memory 18 Zero gas generator 19 Main body case 20 Inlet 21 Outlet 22 Exhalation inflow space 23 Exhalation outflow space 24 Partition wall 25 Vent 26 Adjusting valve 27 Cover 28 Rod 29 Cam 29a Cam shaft 30 Spring 31 Spring receiver 32 Separation membrane 33 Cover 34 Annular wall 35 Bottom surface 36 Top surface 37 Gap 38 Dotted line 39 Connection hole 40 Connection hole

Claims (7)

A measuring device body into which exhaled breath is blown,
A flow regulator in which the exhaled air blown into the measuring device body is adjusted to a predetermined flow rate;
A chamber in which exhaled air flowing out of the flow regulator is temporarily stored;
A pump for supplying exhaled gas stored in the chamber to the measurement unit;
A control unit for controlling the operation of the flow rate regulator;
A first pressure sensor connected to the exhalation inflow side of the flow regulator;
A second pressure sensor connected to the exhalation flow side of the flow regulator;
With
The flow regulator is
A body case having an inflow port for exhalation and an outflow port for exhalation;
A dividing wall that divides the inside of the main body case into an exhalation inflow space on the inflow side and an exhalation outflow space on the outflow side,
A circular vent provided in the dividing wall for allowing exhalation to pass;
A frustoconical adjustment valve slidably disposed in the vent;
Have
The adjustment valve in the shape of a truncated cone has a side surface reduced to the inward side,
Breath measuring device. The adjustment valve has the entire circumference of the side surface reduced to the inward side,
The breath measuring apparatus according to claim 1. The side surface of the regulating valve is reduced inward from the top surface to the bottom surface.
The breath measurement apparatus according to claim 2. The adjustment valve has one end side arranged in the exhalation inflow space and the other end side arranged in the exhalation outflow space.
The breath measuring device according to any one of claims 1 to 3. The regulating valve is provided with a lid for closing the vent on one end side.
The breath measuring apparatus according to claim 4. The regulating valve has a rod on the other end side,
The flow rate adjuster has a cam facing the end on the other end side of the rod,
The cam slides the rod;
The breath measuring device according to any one of claims 1 to 5. The exhalation measuring device includes a first pressure sensor connected to the exhalation inflow space of the flow regulator, a second pressure sensor connected to the exhalation outflow space of the flow regulator,
Have
The control unit controls movement of the cam based on outputs of the first and second pressure sensors.
The breath measuring device according to claim 6.

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