JPH0124622Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a gas leak alarm device that displays an alarm in stages according to the state of reducing gas in indoor air by operating according to the actual situation in the home.

Traditionally, household gas leak alarms detect abnormalities that are different from true gas leaks, such as small gas leaks due to ignition errors, alcohol vapor from drinking sake cans, or smoke from cigarettes or grilled foods when cooking. In order to avoid unnecessary alarms (false alarms) that could occur even if so-called miscellaneous gases were generated indoors, it was necessary to set alarm points so that they would not easily go off in the event of an abnormality of this magnitude. Because of this,
Gas leak alarms rarely operate on a daily basis, and in order to confirm whether or not they are functioning properly, it is necessary to take the trouble of spraying inspection gas on them and confirming their operation.

However, in the home, even such a relatively simple task is seen as a hassle, and although there are many examples of actually preventing gas accidents by installing gas leak alarms, maintenance and inspections are troublesome,
It is also an indisputable fact that the lack of display on gas leak alarms on a daily basis is a major cause of people losing interest in gas leak alarms and hindering their widespread use.

This idea was developed in consideration of the above points, and takes advantage of the inherent high sensitivity of gas detection elements, which had previously been unnecessarily suppressed, and utilizes miscellaneous gases generated in everyday homes, etc., which were thought to be a source of false alarms. By automatically checking the gas leak alarm system and constantly displaying air pollution (abnormality) with an appropriate alarm sound, it is possible to use it as a guide for determining whether ventilation is necessary, and to detect true gas leakage. In the event that a leak occurs and the gas concentration in the room gradually increases, a strong full-scale alarm will be issued to notify the danger and encourage thorough measures to prevent accidents. The object of the present invention is to provide a gas leak alarm device.

This idea will be explained below.

FIG. 1 is a circuit diagram showing an embodiment of this invention. In this figure, _T1 is a power transformer, and a commercial power supply is connected to the primary winding P. The secondary winding S is for heating the gas detection element e. Both ends of the primary winding P serve as a common terminal _t1 and an AC terminal _t2 . Also, the primary winding P
Take an appropriate voltage from the middle of the diode
Rectify and smooth with D ₁ and capacitor C ₁ and set the terminal as t ₃ . e is a semiconductor type gas detection element, Tr1 to Tr
7 is a transistor, BZ is a buzzer, SP is a speaker, T ₂ is a matching transformer, D ₂ and D ₃ are diodes,
DZ is a Zener diode, SCR is a thyristor,
_C1 to _C6 are capacitors, _R1 to _R20 are resistors, VR is a variable resistor, and LED is a light emitting diode.

Diode _D3 and capacitor _C3 constitute a timer circuit, and when an input for a certain period of time or more is applied to diode _D3 , the potential across capacitor _C3 increases, and as described later, transistor Tr4, thyristor SCR, and light emitting Operate diode LED, etc.

Transistors Tr4 to Tr6, etc. constitute a switching circuit, and transistor Tr7, matching transformer _T2 , etc. constitute an oscillation circuit.

Next, the operation will be explained. When power is applied, until capacitor _C2 is charged,
A is the connection point between diode D ₂ and capacitor C ₂
Since the potential at the point is high, transistors Tr1 and Tr2 are both conductive.Therefore, even if the internal resistance of gas detection element e is low, both ends of resistor _R7 are short-circuited, so resistor _R6 and diode D The potential at the connection point B with ₃ is low, so neither the buzzer BZ nor the speaker SP operates. By the time the gas detection element e is heated and stabilized (for example, 90 seconds after the power is turned on), charging of the capacitor _C2 is completed, the potential at point A decreases, transistors Tr1 and Tr2 become non-conductive, and the resistor The short circuit of the resistor _R7 is broken, but since the internal resistance of the gas detection element e and the value of the resistor _R5 are extremely large compared to the resistor _R7 , the potential at point B continues to be kept low, and the diode The input to D ₃ is small and the alarm does not operate. Therefore, unnecessary alarms are not issued when the power is turned on. At this point, the light emitting diode LED lights up.

First Stage Alarm First, suppose there is a gas leak with a low concentration. When the gas detection element e adsorbs gas, its internal resistance decreases according to the amount of gas adsorbed, so that the terminal t ₁ of the primary winding P of the power transformer T ₁ , which until now has mostly been applied to the gas detection element e, , t ₂ are almost all applied to the resistors R ₆ and R ₇ , and therefore the potential at point B increases. At point B, a positive and negative alternating current voltage is output, which is rectified by diode _D3 and charges capacitor _C3 .

When the voltage across the capacitor _C3 exceeds a certain value, first, the transistor Tr4 becomes conductive, the transistor Tr5 becomes non-conductive, and the transistor Tr6 becomes conductive, so that the oscillation circuit including the transistor Tr7 starts oscillating. Therefore, the speaker
SP generates sound according to the oscillation frequency.

In this way, a warning is given that a low concentration gas leak has occurred.

Second-stage alarm This describes what happens when there is a high-concentration gas leak. If the concentration of the leaked gas is high, the gas detection element e
The internal resistance of is also extremely low. Therefore, the AC voltage appearing at point B also increases.

When this AC voltage continues for a certain period of time, the potential across the capacitor _C3 rises, the potential at point C of the slider of the variable resistor VR rises, the thyristor SCR becomes conductive, and the buzzer BZ sounds. . In this way, it is reported that there has been a gas leak of high concentration gas. As described above, in the case of high concentration gas, no alarm is issued unless the operation of the gas detection element e continues for a predetermined period of time. This prevents false alarms regarding temporary items such as non-gas.

Note that in the above embodiment, the speaker SP was used for the first stage alarm, and the buzzer BZ was used for the second stage alarm, but it is also possible to use other sounding devices, or to use the same sounding body but with different frequencies. It's okay. The point is that it is sufficient to be able to distinguish between the first and second stages.

FIG. 2 is a front view showing an embodiment of the gas leak alarm device of this invention. In this figure, 1 is the housing, 2
is the power cord, 3 is the plug, 4 is the power lamp, 5
1 is an inspection port through which gas can be injected, 6 is a sound window formed on the front surface of the housing 1, and 7 is an acoustic tube insertion port. By inserting the tip of a hollow pipe into the acoustic tube insertion port 7, the sound from the speaker SP and buzzer BZ shown in FIG. 1 can be transmitted to a remote point.
Therefore, sound can be combined without electrical connection, so by identifying and detecting this sound, you can, for example, turn on a ventilation fan with the sound of speaker SP, or turn on buzzer BZ.
It becomes possible to close the gas on-off valve with the sound of the sound.

As explained in detail above, this device is designed to issue a first-stage alarm and a second-stage alarm depending on the gas concentration of a gas leak. It is possible to distinguish and reliably detect gas leaks, and accidents caused by gas leaks can be reliably prevented without causing alarms due to false alarms as in the past. Furthermore, since the first stage alarm is emitted by miscellaneous gas, etc., by hearing this alarm sound, you can know that the gas leak alarm device is activated, and it means that you are constantly self-inspecting. This will create a sense of familiarity and security with the gas leak alarm system, which will greatly contribute to its widespread use. Furthermore, the automatic inspection operates at the inspection level, that is, miscellaneous gas, etc., and the alarm sound from the first alarm is low frequency and quiet and does not bother the ears, but the second alarm Since the warning sound is issued from the second alarm device at a high frequency and strong alarm at the level of a normal gas leak alarm, the alarm can be sufficiently effective. In addition, when the power is turned on, the first and second alarms are locked for a predetermined period of time, preventing them from operating. This prevents both alarms from activating when the power is turned on, causing unnecessary anxiety to the user. It has excellent advantages such as being able to prevent

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of this invention, and FIG. 2 is a front view of the same. In the diagram, T ₁ is a power transformer, T ₂ is a matching transformer,
e is a gas detection element, D ₁ to D ₃ are diodes, C ₁ to
_C6 is a capacitor, _R1 to _R20 are resistors, VR is a variable resistor, SCR is a thyristor, LED is a light emitting diode, BZ is a buzzer, and SP is a speaker.

Claims (1)

[Scope of utility model registration request] A gas detection element that changes its resistance value in response to gas leakage, and a first alarm that has a self-inspection function that operates in the first stage when the resistance value change of this gas detection element reaches an inspection level that is activated by miscellaneous gas. a second gas leak alarm level in which the change in resistance of the gas detection element reaches a gas leak alarm level greater than the inspection level;
a second alarm that operates during the first step; and means for locking the operation of the first and second alarms for a predetermined period of time from when the power is turned on; A gas leak alarm device, characterized in that the alarm sound of the second alarm is more powerful and has a higher frequency than the alarm sound of the first alarm.