JP2001066243A - Respiration gas sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently measure the concentration of the low volume respiration gas of a living body in the amount of ventilation with high accuracy. SOLUTION: The central part in the axial direction of a flow-through cell 11 formed from a tubular member is contracted in diameter to form parallel surfaces 11a, and translucent windows 12, 13 are coaxially provided to the parallel surfaces 11a. A parallel surface is formed at the position opposed to the translucent windows 12, 13 of the adaptor 17 fitted in the flow-through cell 11 through a predetermined gap, and a through-hole is formed to the parallel surface on the same axis as the translucent windows 12, 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a respiratory gas sensor used for measuring the gas concentration of respiratory gas of a living body or for determining whether or not breathing is performed, and particularly for a living body having a relatively small amount of ventilation. And a suitable respiratory gas sensor (hereinafter simply referred to as a sensor).

[0002]

2. Description of the Related Art As an apparatus for measuring the concentration of gas such as CO2 in the exhalation of a living body, a device proposed by the present applicant and disclosed in Japanese Utility Model Application Publication No.
A sensor disclosed by JP 8534 is known.
The configuration of this sensor is shown in FIGS. 14 is a front view, FIG. 15 is a plan view, and FIG. 16 is an enlarged sectional view of a main part showing the operation of the present sensor.

In FIG. 1, a sensor 1 comprises a flow-through cell 2 which is a tubular member, an infrared light source section 3 and an infrared detection section 4 provided on the outer periphery in a direction substantially perpendicular to the axis of the flow-through cell 2. I have. The infrared light source unit 3 and the infrared detection unit 4 are provided on the same optical axis, and light-transmitting windows 5 and 6 formed airtight on the outer wall of the flow-through cell 2.
, The infrared rays pass through the flow-through cell 2 in a direction substantially perpendicular to the axis. Then, only the light of 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 section 4, and the gas concentration is measured by a known means.

When the gas concentration is measured by the sensor 1 constructed as described above, if the internal volume of the flow-through sensor is large, the dead space is too large for a living body with a small ventilation, such as a newborn baby, and cannot be used. . In order to solve this problem, in the above-mentioned proposal, as shown in FIGS. 14 to 16, the light transmitting window 5 is fitted to the inner peripheral surface of the flow-through cell 2.
A tubular adapter 7 having a through-hole 7a formed at a position corresponding to 6 was provided. According to this configuration, the internal volume of the sensor 1 is significantly reduced, and the dead space volume is reduced. As a result, it is possible to efficiently measure the concentration of gas such as CO2 in exhaled air of a newborn with a small ventilation.

[0005]

However, according to the conventional sensor constructed as described above, the respiratory gas flows through the small through hole 7b at the center of the adapter 7 and the detection light emitted from the infrared light source unit 3. Only the central part of the gas passes through the breathing gas. For this reason, the light amount of the detection light detected by the infrared detection unit 4 may decrease, and the measurement accuracy may decrease.

[0006] Further, since the breathing gas usually has a humidity close to 100%, when the measurement is repeated ten or more times, the through-hole 7a formed opposite to the light-transmitting windows 5 and 6 of the adapter 7 becomes As shown in FIG. 12, the water drops 8 accumulate and do not flow out. As a result, the water droplets 8 may block the detection light, and may cause a measurement error.

The present invention has been made in view of such a situation, and it is possible to efficiently and accurately measure the concentration of a respiratory gas in 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 having a simple structure.

[0008]

In order to achieve the above object, the present invention according to the first aspect provides an apparatus for transmitting detection light from outside into a gas flowing through a flow path formed by a tubular member. A pair of light-transmitting windows are provided on the peripheral wall of the tubular member in an air-tight manner, fitted on the inner peripheral surface of the tubular member, and provided with an adapter having a through hole formed at a position aligned with the light-transmitting window. In the gas sensor, a slit having the entire width of the light-transmitting window is provided in the outer periphery of the adapter at a position close to and opposed to the light-transmitting window in the axial direction to form the gas flow path. Features.

[0009] The breathing gas sensor according to claim 2 is characterized in that the adapter is divided into two on both axial sides of the light transmitting window.

According to a third aspect of the present invention, the respiratory gas sensor is characterized in that the divided adapter is fixed in the tubular member.

According to a fourth aspect of the present invention, the respiratory gas sensor is characterized in that the two divided adapters are detachably connected within the tubular member.

[0012] The respiratory gas sensor according to claim 5 is characterized in that an anti-fog film is provided on the inner surface of the light transmitting window.

According to a sixth aspect of the present invention, there is provided a respiratory gas sensor comprising a tubular member provided with a gas flow passage therein, and the tubular member having a gas flow passage therein for transmitting detection light from outside to the gas flowing through the flow passage. A pair of light-transmitting windows are provided on the peripheral wall in an air-tight manner, and the tubular member has a partition portion therein for dividing the flow path into two, and the partition portion transmits light from one of the light-transmitting windows to the other. It has a light hole, and the flow path divided by the partition portion is adapted to be along each of the light transmitting windows, and has a width of the entire light transmitting window at a position in contact with the light transmitting window. I do.

According to a seventh aspect of the present invention, there is provided a respiratory gas sensor according to the sixth aspect, wherein an anti-fog film is provided on an inner surface of the light-transmitting window of the sensor.

According to the first aspect of the present invention, a slit having the entire width of the light-transmitting window is provided in the outer periphery of the adapter at a position facing the light-transmitting window and close to the light-transmitting window. Since the path is formed, the entire detection light emitted from the infrared light source and passing through the light transmitting window can irradiate the respiratory gas passing through the gas flow path, and the gas concentration can be measured efficiently and with high accuracy. In addition, since the gas flow path is formed near the light transmitting window, no water droplets accumulate on the inner surface of the light transmitting window.

According to the present invention as set forth in claims 2 to 4,
Since the adapter is divided into two parts, molding becomes easy. In this case, the adapter divided into two parts may be fixed in the tubular member or detachably connected. However, by making the adapter detachable, the adapter is taken out of the tubular member after use, washed, sterilized, and reused. Can be.

According to the fifth aspect of the present invention, since the anti-fog film is provided on the inner surface of the light-transmitting window, the inner surface of the light-transmitting window is prevented from fogging due to the moisture of the respiratory gas passing through the gas flow path. it can.

According to the sixth aspect of the present invention, the same operation as that of the first aspect can be obtained.

According to the seventh aspect of the present invention, an operation similar to the operation of the fifth aspect of the invention can be obtained.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a respiratory gas sensor according to the present invention will be described below 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, FIG. 6 and FIG. 7 are sectional views taken along lines AA, BB and CC of FIG. 1, FIG. 8 is an exploded front view of FIG. 1, and FIG. 9 is an exploded top view of FIG.

The central portion of the flow-through cell 11, which is a tubular member, is reduced in diameter, and a parallel surface 11a is formed at a position symmetric and parallel to the axial direction. Parallel surface 11a
At the center, light-transmitting windows 12 and 13 similar to the conventional example are provided in an airtight manner. Anti-fogging films 14 and 15 are formed on the inner surfaces of the light-transmitting windows 12 and 13, respectively. The parallel plane 11
On at least one side in the axial direction of a, a holding portion 16 projecting to the outer peripheral side and holding the infrared light source portion and the infrared detection portion is integrally formed. Although not shown, an infrared light source section and an infrared detection section are arranged on the outer periphery of the light-transmitting windows 12 and 13 as in the conventional example.

A pair of right and left adapters 17 and 18 are fitted in the flow-through cell 11. A cylindrical flange portion 17a that abuts on the inner peripheral surface of the flow-through cell 11 and abuts on the left side of the axial inner surface of the parallel surface 11a is formed integrally with the adapter 17 on the left side in the figure in the axial direction. ing. A plate-like portion 17b is integrally formed on the right side of the flange portion 17a in the drawing along the central axis, and both surfaces of the plate-like portion 17b face the parallel surface 11a in parallel with a predetermined width interval. . The plate-like portion 17b has a through hole 1 coaxially with the light transmitting windows 12 and 13.
7c is formed. Furthermore, the plate-like portion 1 is provided on the flange portion 17a.
A slit 17d is formed in parallel on both surfaces of 7b.
The gas flow path communicates with a gap formed between both surfaces of the plate portion 17b and the parallel surface 11a.

The adapter 18 on the right side in the figure is formed in a substantially columnar shape, and its outer periphery is formed on the parallel surface 1 of the flow-through cell 11.
1a is in contact with the right inner peripheral surface. 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 with the axial direction. Slit 18
a is a plate-like portion 17b of the adapter 17 and the flow-through cell 1
The gas flow path communicates with the gap formed between the first parallel surface 11a and the slit 17d.

As shown in FIGS. 8 and 9, a lock claw 1 is provided at one end inside the plate-like portion 17b of the adapter 17 so as to be parallel to the axial direction.
9 are provided integrally, and a locking claw 19 is formed at its tip with a mountain-shaped locking portion 19a. On the other hand adapter 18
Is formed with a locking hole 18b.
8 is fitted to a predetermined position in the flow-through cell 11, the locking portion 19a of the locking claw 19 is locked in the locking hole 18b.
And is locked. Locking part 1
9a is formed in a mountain shape having slopes on both sides, so that if the knobs 17e, 18c protruding from the outer end faces of the adapters 17, 18 are gripped and pulled strongly outward, they can be easily locked. Can be canceled.

According to the present embodiment, since the respiratory gas flows through the slit-shaped gas flow path formed between the entire surface of the light-transmitting window 11a and the plate-like portion 17b of the adapter 17, the internal volume of the sensor is reduced. It can be made smaller to reduce the dead space amount and increase the amount of transmitted light. As a result, the respiratory gas concentration of a child or the like with low ventilation can be measured efficiently and with high accuracy with a simple structure. Further, since the gas flow path is formed in a slit shape between the light transmitting window 11a and the plate-like portion 17b of the adapter 17, moisture in the respiratory gas becomes water droplets and becomes water droplets.
Since it does not accumulate on the inner surface of a, the accuracy of gas concentration measurement can be improved.

In the above embodiment, the adapters 17 and 18 are detachable, and the measurement sensor is sterilized and can be reused. However, the adapters 17 and 18 may be fixed in the flow-through cell 11 and may be disposable. Although the measurement is suitable for gas concentration measurement, the presence or absence of respiration can be determined based on the presence or absence of respiratory gas.

Next, a second embodiment of the present invention will be described. In this example, the adapter of the first embodiment has the same form as that fixed in the flow cell, and is formed integrally. 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.

As shown in FIG. 10, a central portion 22 of a flow-through cell 21 which is a tubular member is box-shaped, and has a pair of parallel surfaces 22a. At the center of the parallel surface 22a, a pair of light transmitting windows 23 similar to the conventional example is provided. An anti-fog film 24 is provided inside the light-transmitting window 23, thereby making the light-transmitting window 23 airtight. At both ends of the side of the central portion 22, a pair of holding portions 26 projecting outward and holding the infrared light source portion and the infrared detection portion are integrally formed. 1
Although not shown, an infrared light source section and an infrared detection section are arranged on the outer periphery of the pair of light-transmitting windows 23 as in the conventional example.

As shown in FIGS. 11 to 13, the inside of the flow-through cell 21 is divided into two flow paths by a plate-shaped partition portion 27. The translucent window 23 is provided in the partition 27.
A through-hole 29 is formed on the same optical axis as. Translucent window 2
3 and the partition portion 27, slit-shaped flow paths 31, 3
2 are formed. Here, the width of the flow paths 31 and 32 is
The width is equal to or larger than the entire width of the light transmitting window 23.

According to the present embodiment, the slit-shaped flow path 3 formed between the entire surface of the light transmitting window 23 and the partition 27
Since the respiratory gas flows through 1 and 32, similarly to the first embodiment, the internal volume of the sensor can be reduced, the dead space can be reduced, and the amount of transmitted light can be increased. As a result, it does not accumulate on the inner surface of the light transmitting window 23. Further, according to the present embodiment, since an adapter is unnecessary,
It is easy to manufacture and easy to use. Also, since it can be manufactured at low cost, it can be disposable.

[0031]

As described above, according to the respiratory gas sensor of the present invention, a slit-shaped gas flow path having the entire width of the light transmitting window is formed at a position close to and opposed to the light transmitting window. In addition, it is possible to reduce the dead volume by reducing the internal volume of the measurement sensor and increase the amount of transmitted light. As a result,
With a simple structure, it is possible to measure the respiratory gas concentration of a small amount of ventilation such as a child efficiently and with high accuracy. In addition, since the respiratory gas passes along the entire surface of the light-transmitting window, moisture in the respiratory gas does not become water droplets and accumulate in the light-transmitting window, so that 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. 2;

FIG. 4 is a right side view of FIG. 2;

FIG. 5 is a sectional view taken along line AA of FIG. 1;

FIG. 6 is a sectional view taken along line BB of FIG. 1;

FIG. 7 is a sectional view taken along line CC of FIG. 1;

FIG. 8 is an exploded side view of FIG. 1;

FIG. 9 is an exploded top view of FIG. 2;

FIG. 10 is a perspective view showing the appearance of a flow-through cell according to a second embodiment.

FIG. 11 is a partially cutaway view of FIG. 10;

FIG. 12 is a sectional view taken along line XX of FIG. 10;

FIG. 13 is a sectional view taken along line YY of FIG. 10;

FIG. 14 is a front view showing a configuration of an example of a conventional respiratory gas sensor.

FIG. 15 is a plan view of FIG. 14;

FIG. 16 is an enlarged sectional view of a main part of FIG. 14;

[Explanation of symbols]

11, 21 Flow-through cell (tubular member) 12, 1
3,23 Translucent window 14,15,24 Anti-fog film 17,1
8 Adapter 17d, 18a Slit 17c,
29 Through-hole 27 Partition

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G045 AA40 DB01 FA13 FA25 GC10 JA07 2G057 AA01 AB02 AB06 AC03 BA05 BD01 DB05 DC07 JB05 2G059 AA01 AA05 BB02 BB12 CC20 EE01 FF06 GG00 HH01 KK01 NN01

Claims (7)

[Claims] 1. A pair of light-transmitting windows for transmitting detection light from the outside into a gas flowing in a flow path formed by a tubular member are provided on the peripheral wall of the tubular member in an airtight manner. In a respiratory gas sensor provided with an adapter fitted with a peripheral surface and having a through-hole formed at a position aligned with the light-transmitting window, the respiratory gas sensor is provided at a position on the outer periphery of the adapter which is opposed to and close to the light-transmitting window. A respiratory gas sensor characterized in that a slit having the entire width of the light-transmitting window is provided to penetrate in the axial direction to form the gas flow path. 2. The respiratory gas sensor according to claim 1, wherein the adapter is divided into two on both sides in the axial direction of the light transmitting window. 3. The respiratory gas sensor according to claim 2, wherein the divided adapter is fixed in the tubular member. 4. The respiratory gas sensor according to claim 2, wherein the two divided adapters are detachably connected within the tubular member. 5. The respiratory gas sensor according to claim 1, wherein an anti-fog film is provided on an inner surface of the light transmitting window. 6. A tubular member provided with a gas flow passage therein, and a pair of light-transmitting windows airtightly formed on a peripheral wall of the tubular member for transmitting detection light from outside into a gas flowing through the flow passage. The tubular member is provided internally with a partition for dividing the flow path into two, the partition having a light-transmitting hole through which light from one of the light-transmitting windows passes to the other, and the partition. The respiratory gas sensor is characterized in that the flow paths divided by are formed along the light-transmitting windows, and have a width of the entire light-transmitting window at a portion in contact with the light-transmitting window. 7. The respiratory gas sensor according to claim 6, wherein an anti-fog film is provided on an inner surface of the light transmitting window.