JP4374481B2 - Respiratory gas sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a respiratory gas sensor used when measuring the gas concentration of respiratory air in a living body or determining the presence or absence of breathing, and particularly suitable for a living body with a relatively small ventilation amount. The present invention relates to a gas gas sensor (hereinafter simply referred to as a sensor).
[0002]
[Prior art]
As an apparatus for measuring the concentration of gas such as CO2 in the exhalation of a living body, a sensor proposed by the present applicant and disclosed in Japanese Utility Model Publication No. 4-48534 is known. The structure of this sensor is shown in FIGS. 14 is a front view, FIG. 15 is a plan view, and FIG. 16 is an enlarged cross-sectional view of the main part showing the operation of the present sensor.
[0003]
In the figure, the sensor 1 includes a flow-through cell 2 that is a tubular member, and an infrared light source unit 3 and an infrared detection unit 4 provided on the outer periphery in a direction substantially perpendicular to the axis of the flow-through cell 2. The infrared light source unit 3 and the infrared detection unit 4 are provided on the same optical axis, and infrared flows through the flow-through cells 5 and 6 formed in an airtight manner on the outer wall of the flow-through cell 2. 2 passes through in a direction substantially perpendicular to the axis. Then, only the light having the wavelength absorbed by the gas such as CO2 in the exhaled air flowing through the flow-through cell 2 is detected by the infrared detecting unit 4, and the gas concentration is measured by a known means.
[0004]
When the gas concentration is measured by the sensor 1 configured as described above, when the internal volume of the flow-through sensor is large, a dead space is too large for a living body with a small ventilation, such as a newborn, and cannot be used. In order to solve this problem, in the above-mentioned proposal, as shown in FIGS. 14 to 16, a through hole 7a is formed at a position that fits with the inner peripheral surface of the flow-through cell 2 and aligns with the light-transmitting windows 5 and 6. A tubular adapter 7 was provided. According to this configuration, the internal volume of the sensor 1 is greatly reduced, and the amount of dead space is reduced. As a result, it is possible to efficiently measure the concentration of gas such as CO2 in the exhaled breath of a newborn with a small ventilation.
[0005]
[Problems to be solved by the invention]
However, according to the conventional sensor configured as described above, the respiratory gas flows in the through hole 7b having a small inner diameter at the center of the adapter 7, and only the central portion of the detection light emitted from the infrared light source unit 3 passes through the respiratory gas. Do not pass. For this reason, the light quantity of the detection light which the infrared detection part 4 detects may reduce, and measurement accuracy may fall.
[0006]
In addition, since the breathing gas usually has a humidity close to 100%, when the measurement is repeated 10 or more times, in the through hole 7a formed facing the light transmitting windows 5 and 6 of the adapter 7, FIG. As shown, the water droplet 8 accumulates and does not flow out. As a result, the water droplet 8 blocks the detection light, which may cause a measurement error.
[0007]
The present invention was made in view of such a situation, and has a simple structure that can efficiently and accurately measure the respiratory gas concentration of a living body with a small amount of ventilation without being affected by water droplets. An object of the present invention is to provide a respiratory gas sensor.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 is characterized in that a pair of light-transmitting windows for allowing detection light to transmit from the outside into a gas flowing in a flow path formed by a tubular member is provided in the tubular shape. In a respiratory gas sensor provided with an adapter provided in an airtight manner on the peripheral wall of the member, fitted to the inner peripheral surface of the tubular member, and provided with an adapter in which a through hole is formed at a position aligned with the translucent window, the outer periphery of the adapter and the A slit is provided through the tubular member in the axial direction to form the gas flow path, and the gas flows along the entire light-transmitting window at a position close to the light-transmitting window. It is characterized by being formed .
[0009]
The respiratory gas sensor according to claim 2 is characterized in that the adapter is divided on both sides in the axial direction of the translucent window.
[0010]
The respiratory gas sensor according to claim 3 is characterized in that the divided adapter is fixed in the tubular member.
[0011]
The respiratory gas sensor according to a fourth aspect is characterized in that the divided adapter is detachably connected in the tubular member.
[0013]
The respiratory gas sensor according to claim 5 includes a tubular member provided with a gas flow path therein, and is airtight on a peripheral wall of the tubular member in order to transmit detection light from the outside into the gas flowing in the flow path. The tubular member includes a partition portion that divides the flow path into two, and the partition portion has a through-hole that allows light from one side of the light-transmitting window to pass through to the other. In addition, the flow paths divided by the partition part are formed so as to extend along the light-transmitting windows, respectively, and the gas flows along the entire light-transmitting window at a position in contact with the light-transmitting windows. It is characterized by that.
[0014]
Respiratory gas sensor according to claim 6, characterized in that a antifogging film on the inner surface of the transparent window of the definitive sensor in any one of claims 1 to 5.
[0015]
According to the first aspect of the present invention, a slit is provided in an axial direction between the outer periphery of the adapter and the tubular member to form the gas flow path, and the slit is formed in the translucent window. Since the gas is formed so as to flow along the entire light-transmitting window at a close position, the entire detection light emitted from the infrared light source section and passing through the light-transmitting window irradiates the breathing gas passing through the gas flow path. Therefore, the gas concentration can be measured efficiently and with high accuracy. Further, since the gas flow path is formed in the vicinity of the light transmission window, water droplets do not accumulate on the inner surface of the light transmission window.
[0016]
According to the second to fourth aspects of the present invention, since the adapter is divided, molding becomes easy. In this case, the divided adapter may be fixed in the tubular member or detachably connected. However, by making the adapter detachable, the adapter can be taken out from the tubular member after use, washed and sterilized, and reused. it can.
[0018]
According to the fifth aspect of the present invention, the same action as that of the first aspect of the invention can be obtained.
[0019]
According to the sixth aspect of the present invention, since the anti-fogging film is provided on the inner surface of the light transmission window, it is possible to prevent the inner surface of the light transmission window from being fogged by the moisture of the breathing gas passing through the gas flow path.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of a respiratory gas sensor of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view showing a state where an adapter is attached to a flow-through cell, FIG. 2 is a transverse sectional view of FIG. 1, FIG. 3 is a left side view of FIG. 2, FIG. 4 is a right side view of FIG. 6 and 7 are cross-sectional views taken along lines AA, BB, and CC, respectively, FIG. 8 is an exploded front view of FIG. 1, and FIG. 9 is an exploded top view of FIG.
[0021]
The central portion of the flow-through cell 11 that is a tubular member has a reduced diameter, and a parallel surface 11a is formed at a position parallel to and symmetrical to the axial direction. At the center of the parallel surface 11a, light-transmitting windows 12 and 13 similar to the conventional example are provided in an airtight manner. Further, anti-fogging films 14 and 15 are formed on the inner surfaces of the translucent windows 12 and 13, respectively. A holding portion 16 that protrudes toward the outer peripheral side and holds the infrared light source portion and the infrared detecting portion is integrally formed on at least one axial direction side of the parallel surface 11a. Although not shown in the figure, the infrared light source unit and the infrared detection unit are arranged on the outer periphery of the transparent windows 12 and 13 as in the conventional example.
[0022]
In the flow-through cell 11, a pair of left and right adapters 17 and 18 are fitted. In the center of the adapter 17 on the left side in the figure, a cylindrical flange 17a that is in contact with the inner peripheral surface of the flow-through cell 11 and that is in contact with the left side of the axial inner surface of the parallel surface 11a is integrally formed. ing. A plate-like portion 17b is integrally formed along the central axis on the right side of the flange portion 17a in the drawing, and both surfaces of the plate-like portion 17b face the parallel surface 11a in parallel with a predetermined width. . A through-hole 17c is formed on the plate-like portion 17b coaxially with the transparent windows 12 and 13. Further, slits 17d are formed in the flange portion 17a in parallel with both surfaces of the plate-like portion 17b, and a gas flow path communicating with a gap formed between both surfaces of the plate-like portion 17b and the parallel surface 11a is formed. Yes.
[0023]
The adapter 18 on the right side in the figure is formed in a substantially cylindrical shape, and the outer periphery is in contact with the right inner peripheral surface of the parallel surface 11 a of the flow-through cell 11. The left end surface of the adapter 18 is in contact with the right side of the inner surface in the axial direction of the parallel surface 11a. A pair of slits 18a are formed through the outer periphery of the adapter 18 in parallel to the axial direction. The slit 18a communicates with a gap (slit 17f) formed between the plate-like portion 17b of the adapter 17 and the parallel surface 11a of the flow-through cell 11, and serves as a gas flow path that communicates with the slit 17d .
[0024]
As shown in FIGS. 8 and 9, a lock claw 19 is integrally provided at one end inside the plate-like portion 17 b of the adapter 17 so as to be parallel to the axial direction. A portion 19a is formed. On the other hand, a locking hole 18b is formed in the adapter 18, and when the adapters 17 and 18 are fitted and mounted at predetermined positions in the flow-through cell 11, the locking portion 19a of the lock claw 19 is locked to the locking hole 18b. Is engaged and locked. In addition, since the latching | locking part 19a is formed in the mountain shape which both sides become a slope, if the knobs 17e and 18c which protruded and provided in the outer end surface of the adapters 17 and 18 are hold | gripped and strongly pulled outside, Easy to unlock.
[0025]
According to the present embodiment, since the respiratory gas flows through the slit-like gas flow path formed between the entire surface of the transparent windows 12 and 13 and the plate-like portion 17b of the adapter 17, the internal volume of the sensor is reduced. The amount of dead space can be reduced. As a result, it is possible to efficiently and accurately measure the respiratory gas concentration of a child or the like with a small amount of ventilation with a simple structure. Further, since the gas flow path is formed in a slit shape between the translucent windows 12 and 13 and the plate-like portion 17b of the adapter 17, the moisture in the respiratory gas becomes water droplets and the inner surfaces of the translucent windows 12 and 13 It is possible to improve the accuracy of gas concentration measurement.
[0026]
In the above embodiment, the adapters 17 and 18 can be attached and detached, and the measurement sensor can be sterilized and reused. However, the adapters 17 and 18 may be fixed in the flow-through cell 11 and may be disposable. Moreover, although it is suitable for gas concentration measurement as a measurement, the presence or absence of respiration can also be determined by the presence or absence of respiratory gas.
[0027]
Next, a second embodiment of the present invention will be described. This example is the same form as the adapter of the first embodiment fixed in the flow cell, and is integrally formed. 10 is a perspective view showing the appearance of the flow-through cell, FIG. 11 is a partially cutaway view of FIG. 10, FIG. 12 is a sectional view taken along line XX of FIG. 10, and FIG. 13 is a sectional view taken along line YY of FIG. It is.
[0028]
As shown in FIG. 10, the center part 22 of the flow-through cell 21 which is a tubular member is box-shaped, and a pair of parallel surfaces 22a is formed. In the center of the parallel surface 22a, a pair of light transmission windows 23 similar to the conventional example is provided. An antifogging film 24 is stretched on the inner side of the light transmission window 23, thereby making the light transmission window 23 airtight. A pair of holding portions 26 are integrally formed at both ends of the side portion of the central portion 22 so as to protrude to the outer peripheral side and hold the infrared light source portion and the infrared detecting portion. Although not shown in the figure, an infrared light source unit and an infrared detection unit are arranged on the outer periphery of the pair of light transmission windows 23 as in the conventional example.
[0029]
As shown in FIGS. 11 to 13, the flow-through cell 21 has a flow path divided into two by a plate-like partition portion 27. A through hole 29 is formed in the partition portion 27 on the same optical axis as that of the transparent window 23. Slit-shaped flow paths 31 and 32 are formed between the transparent window 23 and the partition portion 27. Here, the flow paths 31 and 32 are formed along the translucent window 23, respectively, so that the gas flows along the entire translucent window 23 .
[0030]
According to the present embodiment, since the respiratory gas flows through the slit-shaped flow paths 31 and 32 formed between the entire surface of the transparent window 23 and the partition portion 27, as in the first embodiment, the internal volume of the sensor can reduce to Succoth reduce the death腔量, accumulated thereby preventing the inner surface of the transparent window 23 the moisture in the gas becomes a water droplet. Furthermore, according to the present embodiment, since an adapter is unnecessary, manufacturing is easy and work at the time of use is simple. Moreover, since it can manufacture at low cost, it can also be made disposable.
[0031]
【The invention's effect】
As described above, according to the respiratory gas sensor of the present invention, the dead volume can be reduced by reducing the internal volume of the measurement sensor. As a result, it is possible to efficiently and accurately measure the respiratory gas concentration of a child or the like with a small amount of ventilation with a simple structure. In addition, since the breathing gas passes along the entire surface of the light transmission window, moisture in the breathing gas does not become water droplets and accumulate in the light transmission window, and the accuracy of gas concentration measurement can be improved. .
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a state in which an adapter is attached to a flow-through cell of an embodiment of a respiratory gas sensor according to the present invention.
FIG. 2 is a cross-sectional view of FIG.
FIG. 3 is a left side view of FIG.
4 is a right side view of FIG. 2;
5 is a cross-sectional view taken along line AA in FIG.
6 is a cross-sectional view taken along line BB in FIG.
7 is a cross-sectional view taken along line CC in FIG.
FIG. 8 is an exploded side view of FIG. 1;
9 is an exploded top view of FIG.
FIG. 10 is a perspective view showing an appearance of a flow-through cell in the second embodiment.
11 is a partially cutaway view of FIG.
12 is a sectional view taken along line XX in FIG.
13 is a sectional view taken along line YY in FIG.
FIG. 14 is a surface view showing a configuration of an example of a conventional respiratory gas sensor.
15 is a plan view of FIG.
16 is an enlarged cross-sectional view of a main part of FIG.
[Explanation of symbols]
11, 21 Flow-through cell (tubular member) 12, 13, 23 Light-transmitting window 14, 15, 24 Anti-fogging film 17, 18 Adapter 17d, 18a Slit 17c, 29 Through-hole 27 Partition part

Claims (6)

A pair of light-transmitting windows for allowing detection light to pass from the outside into the gas flowing in the flow path formed by the tubular member is provided on the peripheral wall of the tubular member, and fitted to the inner peripheral surface of the tubular member In the respiratory gas sensor provided with an adapter in which a through hole is formed at a position aligned with the translucent window,
A slit is provided in an axial direction between the outer periphery of the adapter and the tubular member to form the gas flow path, and the gas passes through the transparent window at a position close to the transparent window. A respiratory gas sensor, wherein the respiratory gas sensor is formed so as to flow along the whole .   The respiratory gas sensor according to claim 1, wherein the adapter is divided on both sides in the axial direction of the translucent window.   The respiratory gas sensor according to claim 2, wherein the divided adapter is fixed in the tubular member.   The respiratory gas sensor according to claim 2, wherein the divided adapters are detachably connected in the tubular member. Provided with a tubular member provided with a gas flow path inside, and in order to transmit detection light from the outside into the gas flowing in the flow path, a pair of light transmission windows are provided in an airtight manner on the peripheral wall of the tubular member,
The tubular member includes a partition portion that divides the flow path into two,
The partition has a through hole that allows light from one side of the translucent window to pass through the other;
The flow path divided by the partition part is formed so as to be along each of the light transmissive windows, and so that the gas flows along the whole light transmissive window at a position in contact with the light transmissive window. Respiratory gas sensor.   The respiratory gas sensor according to any one of claims 1 to 5, wherein an anti-fogging film is provided on an inner surface of the translucent window.

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