JPS6381594A - Heat/smoke compound sensor - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 〔Technical field〕 TECHNICAL FIELD The present invention relates to an improvement in a combined heat and smoke detector.

[Background technology]

A combined heat and smoke detector is a single detector equipped with a heat sensing part and a smoke sensing part, and detects a fire based on two factors: the rise in temperature when a fire occurs and the change in smoke concentration due to smoke. It was developed to speed up the process.

For this reason, such a conventional combined heat and smoke detector is configured to issue a fire alarm when either the heat sensing section or the smoke sensing section first issues an alarm.

However, in a combined heat and smoke detector with such a configuration, the unreliability of the heat sensing part and the smoke sensing part for non-fire alarm factors can sometimes be combined, and the normal single Problems have been pointed out, such as being more likely to generate false alarms than other detectors (heat detectors, smoke detectors).

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a combined heat and smoke detector that solves the problems associated with soft soil.

[Disclosure of the invention]

The present invention proposed to achieve the above object has a configuration in which the heat and smoke sensing section provided in the composite sensor can be switched to multiple sensitivity modes, and when any one of the sensing sections outputs an alarm signal. Sometimes, the sensitivity mode of the sensing section on the alarm signal output side is set to a low one, and the sensitivity mode of the other sensing section is set to a high one. The structure is such that the alarm signal is output only when the alarm 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 heat and smoke composite sensor A of the present invention includes a heat sensing section 1 and a smoke sensing section 2.
The heat detection section 1 is configured by combining the heat detection circuits 10. It is equipped with a level determination circuit 11 that determines the output level of the heat detection signal from this heat detection circuit 10, and the smoke detection section 2 is equipped with a smoke detection circuit 20 and a level determination circuit 21 similar to the heat detection section 1. . Such a composite sensor A is equipped with three input terminals consisting of a first input terminal LA for forecasting, a second report input terminal LB for book binding, and a common terminal C. The power supply signal from the second input terminal LB is sent to the constant voltage circuit 4 via the diode OR circuit 5.
A first switching means 6 is connected between the first input terminal LA and the common terminal C, and a second switching means 7 is connected between the second input terminal LB and the common terminal C.

Reference numeral 3 denotes a level switching control circuit, which switches and sets the judgment level of each level judgment circuit 11.21 in accordance with the alarm signal output from the level judgment circuit 11.21 of each sensing section 1, 2.

OR gates 1, 2, AND gates 1, 2 and N.

A combinational logic circuit 8 consisting of T gates connects each sensing section 1.
When circuit 2 outputs an alarm signal, it transmits necessary control signals to other circuit sections.

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

In the composite sensor A of the present invention, the heat and smoke sensing sections 1.2 are both set to medium sensitivity mode during monitoring. That is, the output determination level of each level determination circuit 11.21 is set to an intermediate level.

In such a monitoring state, if the heat detection signal output from the heat detection circuit 10 exceeds the set level of the level judgment circuit 11 (judgment level for medium sensitivity mode) and outputs the alarm signal (rHj level), this alarm will be activated. The signal is input to the AND gate 1 via the OR gate 1, but since the control signal of the level switching control circuit 3 is set to the rLJ level at this time, the output of the NOT gate is inverted and becomes r'rI.
J and is sent from the AND gate 1 as a drive signal to the first switching means 6. The first switching means 6 that received 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 OR
Since the diode DI of the circuit 5 is reverse biased and becomes non-conductive, the constant voltage circuit 4 receives power only from the second input terminal LB through the diode D2.

Further, the alarm signal outputted from the level determination circuit 11 and turned on as a drive signal to turn on the first switching means 6 is also sent to the level switching control circuit 3 from the output terminal of the AND gate 1, and receives this signal. Level switching control circuit 3
inverts the control signal to rHJ level and connects AND gate 1
is closed, and at the same time, the level determination circuit 11. of each sensing section 1, 2 is closed.
A level switching control circuit is sent to 21. That is, the level determination circuit 11 of the heat sensing section 1 that outputs the alarm signal is switched to the low sensitivity mode, and the level determination circuit 21 of the other smoke sensing section 2 is switched to the high sensitivity mode.

In this way, in the present invention, when any of the sensing sections 1.2 outputs an alarm signal, the sensitivity mode of each sensing section 1.2 is switched and set based on this alarm signal. After the sensitivity mode switching setting is made, when a second alarm signal is output from the level determination circuit 11.21 of any of the sensing sections 1.2, this alarm signal is sent to the OR gate 2.2.
It will be sent as a drive signal to the second switching means 7 via the AND gate 2, and when the second switching means 7 that receives this drive signal is turned on, it will be book bound and an alarm signal will be sent. is generated.

In the above embodiment, the case where the alarm signal is first outputted to the heat sensing section 1 has been described, but it goes without saying that the same applies to the case where the alarm signal is first outputted to the smoke sensing section 2.

Further, the heat and smoke sensing sections 1 and 2 are not limited to those capable of setting the three sensitivity modes described above, but may be ones capable of switching between two sensitivity modes.

Incidentally, environmental conditions are generally a factor that cannot be ignored as a factor that causes a sensor to generate a false alarm. Especially when it comes to smoke detectors, we cannot ignore the issue of humidity. For example, if a smoke detector is installed in a hot spring area or in a room with high humidity, condensation may accumulate on the smoke detector and cause a false alarm. often occurs. As a countermeasure for this, a humidity sensor is attached to the sensor, and when the output of the humidity sensor exceeds a specified level, an abnormal signal other than a fire alarm is output. It is preferable to use a system that generates a fire alarm based on comprehensive judgment, and a configuration in which a temperature sensor is attached to a smoke detector is suitable for analog smoke detectors as well as ordinary smoke detectors. It goes without saying that the above-mentioned problem can be solved by attaching a humidity sensor to the smoke sensor in the composite sensor of the present invention.

〔Effect of the invention〕

As can be understood from the above explanation, according to the composite sensor of the present invention, the first alarm signal is output in a state of low sensitivity, and the sensing section that outputs the alarm signal further reduces the sensitivity. At the same time, the sensitivity of the detectors that have not yet triggered an alarm is further increased, and the alarm signal is output only after a second alarm signal is obtained. Because alarm (false alarm) factors are eliminated and at the same time monitoring is possible without reducing the detection ability for actual fires, a suitable alarm signal can be obtained and a heat and smoke composite detector with high reliability can be obtained.

[Brief explanation of the drawing]

The figure shows the basic configuration of the heat-smoke composite sensor of the present invention. (Explanation of symbols) A...Thermal and smoke composite sensor of the present invention 1...Heat sensing section 10...Heat detection circuit 11...Level judgment circuit 2...Smoke sensing section 20...Smoke detection Circuit 21... Level determination circuit 3... Level switching control circuit 6... First switching means 7... Second switching means 8... Combinational logic circuit

Claims (3)

[Claims] (1) A combined heat and smoke detector equipped with a heat and smoke sensing section that can set multiple sensitivity modes, and outputs an alarm signal when either the heat or smoke sensor outputs an alarm signal. At the same time, the sensitivity of the sensing section on the side that has been set is switched to a low mode, and the sensitivity of the other sensing section is switched to a high mode. A heat and smoke composite detector characterized in that it is configured to generate an alarm signal only when the alarm signal is output. (2) The heat and smoke detectors mentioned above can all be set to three sensitivity modes: high sensitivity, medium sensitivity, and low sensitivity, and both of the above detectors are set to medium sensitivity mode during monitoring. Therefore, when any of the above sensing units outputs an alarm signal for the first time, the sensor that outputs the alarm signal is set to low sensitivity mode, and the other sensor is switched to high sensitivity mode. The hot smoke composite according to claim 1, wherein the alarm signal is generated only when one of the sensing sections whose sensitivity mode has been switched in this manner outputs an alarm signal. sensor. (3) The thermal smoke composite sensor according to claim 1 or 2, characterized in that a humidity sensor is attached to the smoke sensing section.