JP2000074822A - Airway adapter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the influence of water-drops caused by the moisture in breathing air flowing in a flow tube at the time of gas concentration measurement. SOLUTION: In this airway adapter, an opening is formed on a facing position of a side wall of a flow tube 1, and a hexagonal frame 6 is mounted airtightly on a window part 2 through which an infrared ray is penetrated, and the frame 6 is projected from the inner face of the flow tube 1, and a transparent sheet on which an anti-clouding layer 5 is formed is stretched on the inner face of the frame 6, and water-drops flowing inside the flow tube 1 is prevented from flowing on the anti-clouding layer 5 by flowing them on both sides of the frame 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airway adapter which is attached to, for example, a respirator and measures the concentration of carbon dioxide in breathing air.

[0002]

2. Description of the Related Art When a living body is breathed artificially using an artificial respirator, an airway adapter is attached to the flow path to measure the concentration of carbon dioxide in respired air. FIG. 4 is an external perspective view showing a configuration of an example of a conventional airway adapter. In FIG. 4, the central part of the cylindrical flow tube 1 in the axial direction has a rectangular tubular cross section, and a circular window 2 for transmitting infrared rays is opened at opposing positions on both side walls of this portion. It is formed.

As shown in the sectional view of FIG. 5, a stepped portion 3 whose inner diameter is reduced is formed concentrically on the inner periphery of the window portion 2, and a circle made of polyester or the like is formed through the stepped portion 3. A transparent sheet 4, which is a transparent film formed in a plate shape, is attached to form a transmission window. The inner surface of the transparent sheet 4 has an anti-fog layer 5
Is applied or vapor-deposited.

FIG. 6 is a cross-sectional view corresponding to FIG. 5, showing another example of a conventional fixing method of the transparent sheet 4 to the window 2. As shown in FIG. In FIG. 6, the outer periphery of the transparent sheet 4 is
Thus, it is fixed to the inner periphery of the window portion 2 by caulking or welding from the outside. At this time, the antifogging layer 5 on the inner surface of the transparent sheet 4
Is substantially flush with the inner wall surface of the flow tube 1.

[0005]

However, according to the conventional example shown in FIG. 5, since there is a step between the inner wall of the flow tube 1 and the inner surface of the anti-fog layer 5, the moisture contained in the respiratory air becomes water droplets. As shown in FIG. 7, the water 8 collects in the direction of gravity at the step. For this reason, the amount of light when the infrared light passes through the window 2 is reduced, and there is a possibility that a measurement error may occur.

According to the conventional example shown in FIG. 6, since the inner wall of the flow tube 1 and the inner surface of the anti-fog layer 5 are substantially flush with each other, there is no danger that water will collect on the inner periphery of the window 2. When the airway adapter is placed so that the transmission window is horizontal and water condensed on the flow tube flows along the inner wall of the flow tube 1 in FIG.
As shown in (2), since the light passes over the anti-fog layer 5, a measurement error may occur.

The present invention has been made in view of such a situation, and reduces the influence of water in respiratory gas flowing through a flow tube during measurement, and enables a stable measurement of carbon dioxide gas for a long time. An object of the present invention is to provide an airway adapter for measurement.

[0008]

In order to achieve the above object, the present invention provides a flow tube through which a respiratory gas passes, and a transmission tube formed at a position opposed to a side wall of the flow tube and transmitting infrared light. And a window, wherein a water flow path is provided on the side wall so that water droplets do not pass through the transmission window.

According to the above configuration, when water droplets due to moisture in the respiratory air flowing in the flow tube flow along the inner wall of the flow tube,
The water drops pass through the flow path provided on the side wall, and do not pass over the transmission window. As a result, the infrared light transmitted through the transmission window is not affected by the water droplet, and no measurement error occurs.

[0010] The flow channel can be formed by providing a frame protruding from the inner surface to the side wall. According to this, the water drops pass outside the frame.

If the transmission window is provided on the inner surface of the frame, water droplets do not pass over the transparent window.

Further, if the frame is formed up to the non-squeezed space in the flow tube, a flow path is formed from just before the space to be squeezed, so that water droplets pass through the transparent membrane. It can be further avoided.

Further, if a tapered portion is provided in the narrow portion of the flow tube, it is possible to prevent water droplets from hitting and splashing near the entrance of the space to be narrowed.

Further, if an anti-fog layer is formed on the inner surface of the transmission window, it is possible to prevent the transmission window from fogging.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the airway adapter of the present invention used for measuring carbon dioxide concentration and the like will be described below with reference to the drawings. FIG. 1 is a cross-sectional view along an axis showing a configuration example of an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA of the mounting structure of a transparent sheet 4 in FIG. In these figures, parts corresponding to those of the conventional example shown in FIGS. 4, 5, and 6 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

In FIGS. 1 and 2, the frame 6 is formed in a hexagonal shape, and its flange is in contact with the step 3 of the window 2 formed at a position facing the side wall of the flow tube 1. It fits into the window 2 and is airtightly fixed. Also frame 6
Of the flow tube 1 projects inward from the inner peripheral surface of the flow tube 1. A transparent sheet 4 having a surface formed with an anti-fog layer 5 is fixed to an end face of the frame 6 protruding into the flow tube 1 to form a transmission window. Reference numeral 7 denotes a mounting portion for fixing a unit in which an infrared light emitting portion and a light receiving portion (not shown) are integrated with the flow tube 1.

According to the present embodiment, when the airway adapter is attached to the flow path of the ventilator, water droplets due to moisture in the respiratory air flowing through the flow tube 1 move along the inner wall of the flow tube 1. At this time, as shown in FIG. 3, the water passes through the outside of the frame 6 provided on the inner surface of the flow tube 1 as a water flow path, so that the water droplets are stretched on the inner surface of the frame 6. It does not pass over the antifogging layer 5 of the sheet 4. As a result, the infrared light transmitted through the transparent sheet 4 is not affected by water droplets, and no measurement error of the concentration of carbon dioxide in the respiratory air occurs.

As shown in FIG. 9, the frame 6
A space that is not squeezed in the flow tube 1 may be formed. Here, the frame 6 includes a main body 6a and a pair of ends 6b, and has a hexagonal shape as a whole. The main body 6a has a slightly different outer shape, but has the same configuration as the frame 6 of the above-described embodiment. The main body 6a is fitted in the window 2 in a state where the flange is in contact with the step 3 of the window 2, and is airtight. It is fixed (see FIG. 2). The pair of ends 6b are formed integrally with the flow tube 1 inside the flow tube 1, respectively, and the respective ends reach a space that is not squeezed. Thereby, the flow path is divided by the frame 6 before the water droplet enters the window portion 2, and it is possible to further prevent the water droplet from passing through the transparent film. As shown in FIG. 9, in this example, the inner corner of the flow tube 1 is tapered at the narrowed portion 9, that is, at the entrance of the narrowed space. Thereby, the squeezed portion 9
It is possible to reduce the possibility that water droplets collide with and scatter, and further prevent the water droplets from passing through the transparent film.

In the above embodiment, the case where the frame 6 is formed in a hexagonal shape has been described. However, the shape of the frame 6 is not limited to the hexagonal shape, and the flow resistance of the respiratory air flowing through the flow tube 1 is not limited to the hexagonal shape. Other shapes may be used as long as the shape can be reduced. Even if the transmission window is formed by using sapphire, the same effect can be obtained by the frame.

[0020]

As described above, according to the airway adapter of the present invention, the flow path is formed so that water droplets do not pass through the transmission window for transmitting infrared light, which is formed at the position opposite to the side wall of the flow tube. With this arrangement, water droplets due to moisture in the respiratory air flowing through the flow tube do not pass over the transmission window. As a result,
Infrared light passing through the transmission window is not affected by water droplets, and measurement errors such as gas concentration do not occur.
Measurement can be performed stably for a long time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view along an axis showing a configuration example of an embodiment of a gas concentration measurement airway adapter of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory diagram showing a flow of moisture flowing in the flow tube of FIG. 1;

FIG. 4 is an external perspective view illustrating a configuration of an example of a conventional airway adapter for measuring gas concentration.

FIG. 5 is a cross-sectional view showing a first example of a conventional structure for attaching a transparent sheet to a flow tube.

FIG. 6 is a cross-sectional view showing a second example of a conventional structure for attaching a transparent sheet to a flow tube.

FIG. 7 is an explanatory diagram showing a stay state of water droplets in the case of the first example shown in FIG. 6;

FIG. 8 is an explanatory diagram showing the flow of water droplets in the case of the second example shown in FIG.

FIG. 9 is a partially cutaway perspective view showing the configuration of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flow tube 2 Window part 4 Transparent sheet (transparent film) 5 Anti-fog layer 6 Frame

Claims (6)

[Claims] 1. An airway adapter comprising: a flow tube through which a respiratory gas passes; and a transmission window formed at a position facing a side wall of the flow tube and transmitting infrared light. An airway adapter, wherein a water flow path is provided so that water drops do not pass through the window. 2. The airway adapter according to claim 1, wherein the side wall is provided with a frame protruding from an inner surface thereof. 3. The airway adapter according to claim 2, wherein the transmission window is provided on an inner surface of the frame. 4. The airway adapter according to claim 2, wherein the frame is formed up to a non-squeezed space in the flow tube. 5. The airway adapter according to claim 1, wherein a tapered portion is provided in a narrowed portion of the flow tube. 6. The airway adapter according to claim 1, wherein an anti-fog layer is formed on an inner surface of the transmission window.