JPH0789397B2 - Heat smoke combined sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a combined heat and smoke sensor.

[Background technology]

The combined heat and smoke detector has a heat detector and a smoke detector in one detector, and it is possible to detect a fire based on two factors: the temperature rise when a fire occurs and the change in smoke density due to smoke generation. It was developed to speed up the process.

For this reason, such a conventional heat and smoke composite sensor is configured to generate a fire alarm when either the heat detection unit or the smoke detection unit first issues a warning.

However, in the thermal smoke composite sensor having such a configuration, the unreliability of the heat detection unit and the smoke detection unit with respect to the non-fire alarm factor may sometimes be compounded, and the normal single unit It has been pointed out that it is more prone to false alarms than detectors (heat detectors, smoke detectors).

[Object of the Invention]

An object of the present invention is to provide a combined heat and smoke sensor that solves the above problems.

[Disclosure of Invention]

The present invention proposed to achieve the above object does not have a configuration in which the heat and smoke sensing units provided in the composite sensor can be set to be switched to a plurality of sensitivity modes, and any one of the sensing units outputs a warning signal. Sometimes, the sensitivity mode of the sensor on the output side of the alarm signal is set to be low and the sensitivity mode of the other sensor is set to be high. The configuration is such that an alarm signal is first output when a report signal is output.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

The figure shows the basic configuration of the present invention. The combined heat and smoke sensor A of the present invention is configured by combining a heat detecting unit 1 and a smoke detecting unit 2, and the heat detecting unit 1 includes a heat detecting circuit 10,
The smoke detection unit 2 includes a level determination circuit 11 for determining the output level of the heat detection signal from the heat detection circuit 10. The smoke detection unit 2 includes a smoke detection circuit 20 and a level determination circuit 21 similar to the heat detection unit 1. . Such a composite sensor A has a first input terminal LA for forecasting, a second report input terminal LB for this report, and a common terminal C.
It has three input terminals consisting of the first input terminal LA
And the power supply signal from the second input terminal LB is the diode OR circuit 5
Is supplied to the constant voltage circuit 4 through the first input terminal LA
And a common terminal C, a first switching means 6 is connected, and a second input terminal LB and a common terminal C are connected to a second switching means 7.

Reference numeral 3 is a level switching control circuit, which switches and sets the judgment levels of the respective level judgment circuits 11 and 21 in accordance with the alarm signals output from the level judgment circuits 11 and 21 of the respective sensing units 1 and 2.

A combinational logic circuit 8 consisting of OR gates 1, 2 and AND gates 1 and 2 and NOT gates sends a control signal necessary for other circuit parts when each sensing part 1 and 2 outputs a warning signal. Is.

Next, the basic operation of the present invention will be described.

In the composite sensor A of the present invention, both the heat and smoke sensing units 1 and 2 are set to the medium sensitivity mode during monitoring. That is, the output determination level of each of the level determination circuits 11 and 21 is set to the intermediate level. In such a monitoring state, when the heat detection signal output from the heat detection circuit 10 now exceeds the set level of the level determination circuit 11 (the determination level in the medium sensitivity mode) and a warning signal (“H” level) is output, This alert signal is
The signal is input to the AND gate 1 via the OR gate 1, but at this time, the control signal of the level switching control circuit 3 is set to the “L” level, so the output of the NOT gate is inverted to the “H” level.
Then, it becomes a drive signal from the AND gate 1 and is sent to the first switching means 6. The first switching means 6 receiving this drive signal is turned on, and as a result, the first input terminal LA and the common terminal C are short-circuited and a forecast signal is generated.

When the first switching means 6 is turned on, the diode D1 of the diode OR circuit 5 is reverse biased and becomes non-conductive, so that the constant voltage circuit 4 is supplied with power only from the second input terminal LB through the diode D2.

Further, the alarm signal output from the level determination circuit 11 and used as a drive signal for turning on the first switching means 6 is
The level switching control circuit 3 which is also sent from the output terminal of the AND gate 1 to the level switching control circuit 3 inverts the control signal to the “H” level and closes the AND gate 1.
At the same time, level switching control signals are sent to the level determination circuits 11 and 21 of the sensing units 1 and 2. That is, the level determination circuit 11 of the heat sensing unit 1 that outputs the warning signal is switched to the low sensitivity mode, and the level determination circuit 21 of the other smoke sensing unit 2 is switched to the high sensitivity mode. As described above, in the present invention, when one of the sensing units 1 and 2 outputs the alarm signal, the sensitivity mode of each sensing unit 1 and 2 is switched and set based on the alarm signal. After the sensitivity mode switching setting like this is made,
When the second alarm signal is output from the level judgment circuits 11 and 21 of either of the sensing units 1 and 2, this alarm signal is OR gate 2 and AN.
It will be sent as a drive signal to the second switching means 7 via the D gate 2, and when the second switching means 7 receiving this drive signal is turned on, this report will be issued and an alarm signal will be issued. Is generated.

In the above embodiment, the case where the warning signal is first output to the heat sensing unit 1 has been described, but it goes without saying that the same applies when the smoke detection unit 2 first outputs the notification signal.

Further, the heat / smoke detectors 1 and 2 are not limited to those capable of setting the above-described three-sensitivity mode, and may be those capable of switching between two sensitivities.

In general, there are environmental conditions that cannot be ignored as factors that cause false alarms by a sensor. Especially when it comes to smoke detectors, the issue of humidity cannot be ignored. For example, when a smoke detector is installed in a hot spring area or a room with high humidity, dew condensation naturally attaches to the smoke detector, resulting in a false alarm. Often occurs. As a countermeasure against this, a humidity sensor is attached to the sensor so that an abnormal signal other than a fire alarm is output when the output of the humidity sensor exceeds a specified level. It is preferable to make a system that comprehensively judges and issues a fire alarm, and the structure in which such a humidity sensor is attached to the smoke detector is suitable not only for a normal smoke detector but also for an analog smoke detector. It goes without saying that it can be applied. It goes without saying that, in the composite sensor of the present invention, the above-mentioned problem can be solved by attaching the humidity sensor to the smoke sensor.

〔The invention's effect〕

As can be understood from the above description, according to the composite sensor of the present invention, it is possible to output the first alarm signal in a state where the sensitivity is low, and the sensing unit that has output the alarm signal further lowers the sensitivity. At the same time, the non-fire alarms unique to each of the heat and smoke detectors have been constructed because the detectors that have not yet issued alarms have a structure in which the sensitivity is further increased and the alarm signal is output only after the second alarm signal is obtained. (False report) Factors can be eliminated, and at the same time, monitoring can be performed without deteriorating the ability to detect an actual fire, so that a suitable alarm signal can be obtained and a highly reliable heat and smoke combined sensor can be obtained.

[Brief description of drawings]

The figure shows the basic configuration of the combined heat and smoke sensor of the present invention. (Explanation of symbols) A: The present invention's combined heat and smoke sensor 1 ... Heat detector 10 ... Heat detection circuit 11 ... Level determination circuit 2 ... Smoke detection unit 20 ... Smoke detection circuit 21 ... Level determination Circuit 3 ... Level switching control circuit 6 ... First switching means 7 ... Second switching means 8 ... Combination logic circuit

Claims (3)

[Claims] 1. A thermal smoke composite sensor having a heat and smoke detector capable of setting a plurality of sensitivity modes, wherein when either one of the heat and smoke detectors outputs an alarm signal, an alarm signal is issued. Is set so that the sensitivity of the sensor on the output side is switched to a low mode and the sensitivity of the other sensor is switched to a high mode. The combined heat and smoke sensor is characterized in that the alarm signal is generated only when the alarm signal is output. 2. The heat and smoke detectors can be set to three sensitivity modes of high sensitivity, medium sensitivity, and low sensitivity, and both the detectors are set to the medium sensitivity mode during monitoring. When any of the above sensing units first outputs a warning signal, the sensing unit that outputs the warning signal is set to low sensitivity mode and the other sensing unit is switched to high sensitivity mode. The heat according to claim 1, which is configured to generate an alarm signal only when one of the sensing units set to switch the sensitivity mode in this way outputs a warning signal. Smoke compound detector. 3. The combined heat and smoke sensor according to claim 1 or 2, wherein a humidity sensor is attached to the smoke detector.