JP3098137B2 - Gas leak alarm device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas leak alarm device for detecting and notifying gas leaking into a room, and more particularly to a gas leak alarm of a two-stage system for giving a two-stage alarm according to the leaked gas concentration. Related to the device.

[0002]

2. Description of the Related Art With the advancement of science and technology, environmental pollution has continued to increase and has become a social problem. In particular, even in general households, in recent years, improvements in building technology, improvements in building materials, etc. have been made to improve sealing performance. Conventionally, gas that could be a naturally diffused pollution source remained in the building or did not previously occur. The danger of accidents is increasing because toxic gases are emitted from building materials in the early stage of the fire.

[0003] In some cases, humans can perceive danger from odors or respiratory systems due to odor or discomfort, but it is impossible to determine the type and concentration of dangerous gas. In addition, depending on the work load at that time, the sense of sensation is not constant, and the danger cannot be completely prevented. For this reason, for example, a high pressure gas safety association has established regulations for gas sensors used in household gas leak alarm devices. In addition, for various industrial gas sensors, JIS (Japanese Industrial Standards) defines sensor specifications for combustible gas. According to this, the structure of the alarm device is to be made by using both an alarm red lamp and a buzzer, and the mechanism is Lower Explosive Limits (hereinafter, LEL).
Alarm at gas concentrations in the range of 1/100 to 1/4 of -10 ° C to + 40 ° C.
It is mentioned as one of the necessary conditions that the device can operate within the range and maintain the accuracy.

[0004] Based on such a rule, the conventional gas leak alarm device incorporates a two-stage alarm system in consideration of safety. This system sets the first-stage alarm level to 1/100 LEL, notifies the user of the situation where the room is being contaminated by flashing a lamp, etc., and sets the second-stage alarm level to 1/4 LEL. The user is notified of the state by a buzzer, sound, or the like.

FIG. 4 shows the relationship between the gas concentration and the output voltage of a gas sensor in a conventional gas leak alarm device. As the concentration of the pollutant gas increases, the output voltage of the sensor increases, and the value a (1/100) as the first-stage alarm level
LEL), the lamp flashes. In this state, the buzzer sounds when the b level (１ ／ LEL) as the second alarm level is reached.

[0006]

As described above, in the conventional gas leak alarm device, the first-stage alarm level is 1/100.
LEL, the second-stage alarm level is set to 1/4 LEL. Therefore, in the range of 1/100 LEL to 1/4 LEL, the user is only informed of the blinking of the lamp as a situation where the room is becoming contaminated. However, from a safety point of view, for example, even if the gas concentration itself is contaminated with 1/5 LEL, but it is at a level that cannot be said to be a dangerous state, if the state continues for a long time, it will not affect the human body. I can't say. Further, when a plurality of polluting sources are mixed, the air as a whole is polluted even if the concentration of each gas is low, and it can be said that the user is uncomfortable. As described above, the conventional gas leak alarm device does not reach the alarm level of the second stage (Ｌ LEL), but is used for a gas concentration state that is considered to have a bad effect on the human body in the case of prolonged exposure. Was not sufficiently alerted, and there was a problem in terms of safety.

[0007] The present invention has been made in view of the above problems, and its object is not limited to the case of high-concentration gas leakage, and also utilizes the state in which the room is polluted at a low level for a long time with various gases. It is an object of the present invention to provide a gas leak alarm device that can reliably draw attention to a person and is highly reliable from the viewpoint of safety.

[0008]

A gas leak alarm device according to the present invention comprises a gas concentration detecting means for detecting the concentration of a leaked gas, and a gas concentration detected by the gas concentration detecting means. Determining means for determining whether the alarm level has reached the first alarm level or a second alarm level higher than the first alarm level; and the gas concentration detected by the gas concentration detecting means has reached the first alarm level. First alarm means for issuing an alarm when the temperature has reached, time-lapse means which is activated at the same time as the first alarm means issues an alarm, and the gas concentration detected by the gas concentration detecting means becomes a second alarm level. A second alarm means for issuing a higher-level alarm than the first alarm means when the alarm has been reached; and an alarm action for the first alarm means when the alarm state of the first alarm means has continued for a predetermined time. From And a warning change-over means for switching the serial second warning means.

In this gas leak alarm device, the low-level pollution state by the first alarm means has continued for a certain period of time, not only when the gas concentration detected by the gas concentration detection means has reached the second alarm level. Also in this case, an alarm is issued by the second alarm means, thereby strongly urging the user to ventilate.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block configuration of a gas leak alarm device according to one embodiment of the present invention. This gas leak alarm device detects a gas concentration of carbon monoxide (CO), carbon dioxide (CO ₂ ) or the like in a room and converts the gas concentration into an electric signal (voltage). The control unit 20 controls the entire alarm device, and an alarm unit 30 that issues an alarm to a user under the control of the control unit 20.

The control unit 20 includes a CPU (central processing unit) 21
It has. The CPU 21 is connected to each unit of the device via a bus. Of these, a ROM (read only memory) 22 stores a program for controlling the operation of each unit of the apparatus as shown in a flowchart (FIG. 3) described later. RAM (random access memory) 23
Has a predetermined first alarm level (for example, 1 /
100 LEL) and a second alarm level (eg, 1 /
4LEL), data read from the gas sensor 10, and the like are temporarily stored. The input port 24 is an A / D (analog / digital) converter 25
This is an interface for sending an output voltage signal of the gas sensor 10 converted into a digital signal to the CPU 21. The CPU 21 controls the timer 27 and the alarm unit 30 as time elapse means based on this signal. The output port 26 is an interface for sending the control signal sent from the CPU 21 to the alarm unit 30.

The alarm unit 30 is a lamp 3 as a first alarm unit that alerts the user visually by blinking.
2. It has a buzzer 33 as a second alarm means for informing the user of a danger state through hearing by sounding, and a drive circuit 31. The drive circuit 31 receives the control signal sent from the CPU 21, and selectively operates the lamp 32 and the buzzer 33.

FIG. 2 shows the relationship between the elapsed time from the start of measurement by the gas sensor 10 and the change in the output voltage of the gas sensor 10. In the present embodiment, the lamp 32 is turned on and off at the time point A, The buzzer 33 sounds at each time.

Next, the operation of the gas leak alarm device of this embodiment will be described with reference to the characteristic diagram shown in FIG. 2 and the flowchart shown in FIG.

First, the CPU 21 resets the timer 27 prior to measurement (step S300), and monitors a detection signal from the gas sensor 10. That is, the gas sensor 1
The gas concentration in the air converted into the voltage value V by 0 is compared with the lower limit a as the first alarm level (step S301). Then, when V ≧ a (Y), the voltage value V is compared with the upper limit value b as the second alarm level (step S302). If V ≧ b (Step S
At 302; N), the buzzer 19 is sounded at the time point B shown in FIG. 2 as a dangerous state (step S30).
6). This alerts the user and strongly encourages ventilation.

On the other hand, if V <b (step S302;
In Y), the CPU 21 blinks the lamp 32 to call the user's attention and activates the timer 27 (step S303). If the voltage value V has not reached the upper limit value b even after a predetermined period of time α has elapsed, the blinking of the lamp 32 is stopped at the time point C shown in FIG. 2 (step S305). Then, the buzzer 19 sounds (step S306), and an alarm is issued to the user to strongly encourage ventilation.

As described above, in the gas leak alarm device of the present embodiment, when the output voltage V of the gas sensor 10 reaches the lower limit value a, the lamp 32 is turned on and off, the timer 27 is started, and the predetermined time α is further elapsed. Even gas sensor 10
If the output voltage has not reached the upper limit value b, the alarm is switched to the buzzer 33. That is, the gas sensor 10
Incorporates a time factor into the process of issuing an alarm based on the gas concentration data detected in step 2. An alarm can be issued by 33, further improving safety.

The present invention has been described with reference to the embodiments.
The present invention is not limited to the above-described embodiment, and can be variously modified without changing the gist thereof. For example, in the above embodiment, one gas sensor 10 and the alarm unit 30
Has shown an example using the lamp 32 and the buzzer 33, but it is also possible to incorporate a plurality of gas sensors 10 and incorporate sound into the alarm unit 30. Furthermore, by setting in advance the relationship between the concentration, the time limit of exposure and the symptoms, etc. according to the type of gas, the location of contamination, the status of contamination, warning of symptoms, coping methods, etc. are notified by voice. For example, a more detailed alarm can be issued.

[0020]

As described above, according to the gas leak alarm device of the present invention, in addition to the alarm corresponding to the gas concentration, the alarm is issued in consideration of the exposure time in the specific concentration range, so that the room is indoors. In the case where the gas is contaminated by miscellaneous gas or the like for a long time and may have a bad influence on the human body, the user's attention can be surely attracted, and the safety is further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a gas leak alarm device according to one embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between an elapsed time from the start of measurement by the gas leak alarm device of FIG. 1 and an output voltage of a gas sensor.

FIG. 3 is a flowchart for explaining the operation of the gas leak alarm device of FIG. 1;

FIG. 4 is a characteristic diagram illustrating a relationship between a gas concentration and an output voltage of a gas sensor in the gas leak alarm device of FIG.

[Explanation of symbols]

 Reference Signs List 10 gas sensor 20 control unit 21 CPU (central processing unit) 22 ROM 27 timer 30 alarm unit 32 lamp (first alarm unit) 33 buzzer (second alarm unit)

Claims (1)

(57) [Claims] 1. A gas concentration detecting means for detecting a concentration of a leaked gas, wherein a gas concentration detected by the gas concentration detecting means is lower than a predetermined first alarm level or a predetermined alarm level. Determining means for determining whether or not a high second alarm level has been reached; and determining whether the gas concentration detected by the gas concentration detecting means has a first level.
First alarm means for issuing an alarm when the alarm level reaches the second alarm level; time-lapse means for starting at the same time as the first alarm means issues an alarm;
A second alarm means for issuing an alarm of a higher level than the first alarm means when the alarm level of the first alarm means has been reached; and An alarm switching unit for switching from the first alarm unit to the second alarm unit.