JP3905455B2 - Gas mask with gas sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas sensor-equipped gas mask provided with a gas sensor that detects breakthrough of toxic gas from an absorption can.
[0002]
[Prior art]
In general gas masks with a gas sensor, an absorption can is attached to the outer surface of the face piece via an absorption can / sensor mounting adapter, and an intake opening that allows the inside and outside of the face piece to communicate with the downstream side of the absorption can, and leakage from the absorption can A gas sensor that detects gas and informs the replacement timing of the absorption can is provided (see Patent Document 1 and Patent Document 2).
By the way, when the absorber can protrudes greatly from the face piece, the lower part of the field of view is blocked and the workability deteriorates. Therefore, it is desirable to shorten the protruding amount of the absorber.
[0003]
However, if the distance between the absorption can and the gas sensor is too close, the entire amount of leaked gas that has passed through the absorption can cannot contact the gas sensor, so that the detection sensitivity of the gas sensor decreases.
Also, in order to improve the detection sensitivity of the gas sensor, even if an attempt is made to install the gas sensor at a position where the leaked gas concentrates, the flow of gas leaking from the absorption canister depends on the shape of the adsorbent filled in the absorption canister and the filling status. It varies depending on the shape of the absorption canister, the shape and position of the intake port, and the like.
Therefore, the flow of gas leaking from the absorption can is irregular and difficult to predict. In reality, it is difficult to reliably detect toxic gas when the distance between the gas sensor and the absorption can is close.
[0004]
[Patent Document 1]
JP-A-57-131458 [Patent Document 2]
Japanese Patent Laid-Open No. 9-196830
[Problems to be solved by the invention]
It is an object of the present invention to provide a gas mask with a gas sensor capable of effectively guiding leakage gas from the absorption can to the gas sensor even when the distance between the absorption can and the gas sensor is short, and increasing the detection sensitivity of the gas sensor. And
[0006]
[Means for Solving the Problems]
The gas sensor with a gas mask of the present invention, is formed canister fitting tube to the facepiece of the outer surface, canister for collecting toxic gas into the canister fitting tube is attached Oite downstream of the canister inside the canister fitting tube, it is installed a gas sensor for detecting toxic gas, the inside of Oite the canister fitting tube between said canister and said gas sensor, the gas leaked from the canister guide plate for inducing toward the gas sensor that has been installed.
Most of the gas leaked from the absorption can is guided to the induction plate and once passes through the position of the gas sensor before reaching the intake port.
[0007]
In order to guide the leaked gas toward the gas sensor, the guide plate may be formed with a through hole at a position facing the detection surface of the gas sensor, and may be formed with a plurality of slits having one end extending toward the through hole. .
In this case, the gas collected in the through hole can be reliably guided to the gas sensor by bringing the outlet of the through hole closer to the gas sensor than the outer periphery of the guide plate.
In order to guide the gas to the through hole more efficiently, a rib having one end portion extending toward the through hole may be formed between the slits on the surface of the guide plate facing the absorption can.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
1 to 6 show a first embodiment of the present invention.
As shown in FIGS. 2 and 3, the gas sensor-equipped gas mask of the present invention includes a face body 1 that covers a wearer's nose and mouth, and an absorption can 2 that is detachably attached to the outer surface of the face body 1.
The face body 1 can be attached to the face with a belt or the like, and a circular absorbent can fitting tube 4 is formed on the outer surface thereof.
[0009]
A screw groove 10 is formed on the outer peripheral surface of the absorption can fitting cylinder 4, and the absorption can 2 is fitted inside the absorption can fitting cylinder 4, and a tightening ring 11 is put on the outer surface of the canister fitting cylinder 4. The absorption can 2 is attached by screwing the formed screw groove and the screw groove 10 of the absorption can fitting cylinder 4.
An intake port 5 communicating with the inner surface of the face piece 1 and a gas sensor 6 for detecting toxic gas are installed on the inner side surrounded by the absorption can fitting cylinder 4, that is, on the downstream side of the absorption can 2.
[0010]
A circuit unit 8 that houses a circuit board, a battery, and an alarm device 7 is mounted below the face piece 1. Further, the circuit board, battery, and alarm device 7 housed in the circuit unit 8 and the gas sensor 6 installed inside the absorption can fitting cylinder 4 include a circuit unit mounting adapter 9 provided in the lower part of the face piece 1. Are connected by lead wires that pass through.
The gas sensor 6 emits a signal when it detects the toxic gas that broke through the absorption can 2, and the alarm device 7 issues an alarm by sound or light in response to this signal.
As described above, since the gas sensor 6, the lead wire, and the circuit unit 8 are incorporated in the face body 1, the gas mask is reduced in size, and the lead wire is exposed to the outside, and there is no fear of being caught by an object.
[0011]
As shown in FIGS. 1 and 2, the guide plate 3 is accommodated between the gas sensor 6 and the absorption can 2 so as to cross the cross section inside the absorption can fitting cylinder 4.
The guide plate 3 is made of a plastic plate having a thickness of about 1 mm, and a through-hole 12 is formed at a position facing the detection surface of the gas sensor 6 as shown in FIGS. The through-hole 12 has a shape that extends in a substantially fan shape from a portion that coincides with the detection surface of the gas sensor 6.
In addition, the guide plate 3 is formed with a plurality of slits 13 extending so that one end portion is concentrated toward the through hole 12.
[0012]
As shown in FIG. 5, among the gases leaked from the absorption can 2, the gas that matches the through holes 12 and the slits 13 and does not hit the guide plate 3, as shown by the arrows a and b, Although it passes through the slit 13 and flows directly downstream of the guide plate 3, the gas hitting the guide plate 3 is guided in the direction of the gas sensor 6 by the shape of the through-hole 12 and the slit 13, as indicated by the arrow c, and the gas sensor. It flows from the vicinity of 6 to the downstream side of the guide plate 3.
Therefore, most of the gas leaked from the absorption can 2 passes near the gas sensor 6 and comes into contact with the detection surface before reaching the intake port 5.
[0013]
In order to verify the change in detection sensitivity of the gas sensor 6 depending on the presence or absence of the guide plate 3, the basic performance of the gas sensor 6 itself with respect to toluene and the output value of the gas sensor 6 when the vapor of toluene is actually vented to the absorption can 2 Examined.
In FIG. 6, a broken line (A) indicates the basic performance of the gas sensor 6 with respect to toluene, a broken line (B) indicates an output value of the gas sensor 6 when the guide plate 3 is installed, and a broken line (C) indicates the guidance. The output value of the gas sensor 6 when there is no plate 3 is shown.
From this result, assuming that 25 ppm, which is half of the allowable concentration of toluene (50 ppm), is an alarm value, about 60% of the output value that the gas sensor 6 should originally output in the broken line (c) where there is no guide plate 3 at this toluene concentration. On the other hand, the broken line (B) where the guide plate 3 is installed has an output value of 90% or more, and the effect of increasing the detection sensitivity by the guide plate 3 can be confirmed.
Also, the output value when the guide plate 3 was provided was about 10% lower than the original output value of the gas sensor 6. However, since the increasing tendency of the output value with respect to the gas concentration is almost the same, if the alarm value is changed from 25 ppm to 20 ppm in advance, the alarm can be sounded at 25 ppm as a result.
[0014]
FIG. 7 shows the guide plate 3 according to the second embodiment.
If there is a margin between the absorption can 2 and the gas sensor 6, a cylinder 14 is attached to the surface of the guide plate 3 facing the gas sensor 6 so as to surround the through hole 12, and serves as an outlet of the through hole 12. The tip of 14 is brought closer to the gas sensor 6 than the outer periphery of the guide plate 3. In addition, on the surface facing the absorbent can 2, ribs 15 having one end extending toward the through hole 12 are formed between the slits 13.
When this guide plate 3 is installed, the gas leaked from the absorption can 2 is easily guided to the ribs 15 and gathers into the through holes 12, and the gas that has passed through the through holes 12 and the cylinders 14 is reliably transferred to the detection surface of the gas sensor 6. Since it is induced, the detection sensitivity to the leaked gas is improved.
Other configurations are substantially the same as those of the first embodiment.
[0015]
FIG. 8 shows the guide plate 3 according to the third embodiment.
The shape of the guide plate 3 is formed in a substantially conical shape with the portion of the through hole 12 facing the gas sensor 6 as a vertex, and the outlet of the through hole 12 is made closer to the gas sensor 6 than the outer peripheral portion of the guide plate 3.
When the guide plate 3 is installed, the leaked gas is guided by the conical guide plate 3 and gathers in the through hole 12 and is reliably guided from the through hole 12 toward the detection surface of the gas sensor 6.
Other configurations are substantially the same as those of the first embodiment.
[0016]
【The invention's effect】
According to the first aspect of the present invention, the gas leaking from the absorption canister is guided toward the gas sensor. Therefore, even if the distance between the absorption canister and the gas sensor is reduced, most of the leaked gas is filled in the absorption canister. Without being affected by the adsorbent, the intake valve, etc., the gas sensor reaches the intake port after contacting the detection surface of the gas sensor, so that the detection sensitivity of the gas sensor is improved.
According to the second aspect of the present invention, the leaked gas can be guided to the gas sensor with a simple structure.
According to the third aspect of the invention, the leakage gas collected in the through hole can be reliably guided to the gas sensor, so that the detection sensitivity for the leakage gas is improved.
According to the fourth aspect of the present invention, the leaked gas is guided to the rib and efficiently guided to the through hole.
[Brief description of the drawings]
FIG. 1 is a front view of a gas mask with a gas sensor according to the first embodiment with an absorption can removed. FIG. 2 is an exploded perspective view of the gas mask with a gas sensor. FIG. 3 is an exploded side view of the gas mask with a gas sensor. FIG. 4 is a front view of the guide plate. FIG. 5 is a view showing the gas flow. FIG. 6 is a view showing the relationship between the gas flow and the output of the gas sensor. FIG. 8 is a perspective view of a guide plate according to a third embodiment.
DESCRIPTION OF SYMBOLS 1 Face body 2 Absorbing can 3 Guide plate 4 Absorbing can fitting cylinder 5 Inlet 6 Gas sensor 7 Alarm device 8 Circuit unit 9 Circuit unit adapter 10 Screw groove 11 Tightening ring 12 Through hole 13 Slit 14 Cylindrical body 15 Rib

Claims (4)

Is the outer surface in the canister fitting tube of tetrahedron form, canister is mounted for trapping toxic gases into the canister fitting tube, inside of Oite the canister fitting tube downstream of the canister the gas sensor for detecting toxic gas is installed on the inside of Oite the canister fitting tube between said canister and said gas sensor, guide plate the gas leaked from the canister to guide toward the gas sensor Gas mask with gas sensor, characterized in that is installed .   2. The gas sensor-equipped gas mask according to claim 1, wherein the guide plate is formed with a through hole at a position facing the detection surface of the gas sensor, and a plurality of slits having one end extending toward the through hole.   The gas mask with a gas sensor according to claim 2, wherein an outlet of the through hole is closer to the gas sensor than an outer peripheral portion of the guide plate.   The gas sensor-equipped gas mask according to claim 2 or 3, wherein at a surface of the guide plate facing the absorption can, a rib having one end portion extending toward the through hole is formed between the slits.

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