JP2016189107A - Fire sensor and fire detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fire sensor and a fire detection system that are capable of improving detection accuracy with a multi-sensor after eliminating a limit in the number of installed fire sensors.SOLUTION: A fire sensor includes: a gas detector (21) that detects carbon monoxide concentrations in a space to be monitored and is composed of electrochemical type gas sensors (21a) generating electromotive forces in accordance with the carbon monoxide concentrations; a constant voltage circuit (22) for converting the electromotive forces generated by the gas detector into electric power supply having a constant electric voltage; a sensing part (23) that receives the supply of the electric power supply from the constant voltage circuit and detects whether fire has occurred or not by sensing physical phenomena caused by fire; and a fire signal outputting part (24) that receives the supply of the electric power supply from the constant voltage circuit and outputs a contact signal that comes to be in a closed state when the occurrence of fire is detected by the sensing part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fire detector installed in each alert area to detect the occurrence of a fire and a plurality of fire detectors, and receives a fire signal from each fire detector, thereby defining the fire occurrence area. The present invention relates to a fire detection system to be identified and announced.

  Examples of fire detectors that detect physical phenomena due to fire include smoke detectors and heat detectors. As a conventional smoke detector, infrared light emitted from an infrared light emitting diode is irradiated into the smoke detection chamber, and if there is smoke in the smoke detection chamber, the infrared light hits the light and scatters. There is one in which smoke is detected when a light receiving photodiode receives scattered light (for example, see Patent Document 1).

  Some heat detectors use a heat detection element such as a thermistor.

  The receiver receives fire signals from various fire detectors installed in each warning area, quickly detects the occurrence of the fire and the occurrence area, and displays and sounds as necessary. It has a configuration that can issue an alarm.

JP-A-6-138031

However, the prior art has the following problems.
Conventional fire detectors such as smoke detectors and heat detectors need to supply power necessary for fire detection operation from the outside. Therefore, based on the electrical change (short circuit) of the voltage of the sensor line caused by closing the electrical contact of the activated sensor by sending and wiring the fire sensor through the common line for each warning area In the “P-type system” that determines fire, there is a problem that the number of installed fire detectors is limited due to power supply restrictions.

  In addition to smoke detection and heat detection, as a fire detector, a gas sensor that detects CO (carbon monoxide) gas concentration generated at the time of combustion with high accuracy has attracted attention, and a multi-sensor including such a gas sensor. It is desired to improve the fire detection accuracy by using.

  The present invention has been made in order to solve the above-described problems, and realizes improvement in detection accuracy by a multi-sensor while substantially eliminating the limit on the number of fire detectors installed in a P-type system. The purpose is to obtain a fire detector and a fire detection system that can be used.

  A fire detector according to the present invention includes a gas detector configured of an electrochemical gas sensor that detects a carbon monoxide concentration in a monitoring target space and generates an electromotive force according to the carbon monoxide concentration, and a gas detector. A constant voltage circuit that converts the generated electromotive force into a power source having a constant voltage, a sensing unit that receives the supply of power from the constant voltage circuit and senses the occurrence of a fire by sensing a physical phenomenon due to a fire, And a fire signal output unit that outputs a contact signal that is closed when a fire is detected by the sensing unit when power is supplied from the constant voltage circuit.

  Moreover, the fire detection system according to the present invention is a fire detection system including a receiver in which a plurality of fire detectors of the present invention are connected as a P-type system, and the receiver supplies power to the plurality of fire detectors. A fire detector that has been activated by CO gas generated by a fire without supplying it, and that has detected a fire at the sensing unit and the contact signal has been closed, is identified from the difference in resistance value, and the identified fire Informs that a fire has occurred in the sensor installation area.

  According to the present invention, a fire detector is configured using a gas sensor having a gas detection function and a battery function, so that the restriction on the number of fire detectors installed in the P-type system is substantially eliminated. It is possible to obtain a fire detector and a fire detection system capable of improving detection accuracy by a sensor.

It is a whole lineblock diagram of a fire detection system in Embodiment 1 of the present invention. It is an internal block diagram of the fire detector applied to the fire detection system in Embodiment 1 of this invention.

  Hereinafter, preferred embodiments of a fire detector and a fire detection system of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is an overall configuration diagram of a fire detection system according to Embodiment 1 of the present invention. The fire detection system according to the first embodiment is configured such that a plurality of fire detectors 20, termination resistors 40, and the like are connected to the receiver 10 via sensor lines 30 for each warning area.

  The fire detection system according to the first embodiment is assumed to be a P-type system, and a weak current for monitoring disconnection of the sensor line 30 flows through the sensor line 30. Here, the fire detector 20 that has been activated by detecting a fire is in a short-circuit state, thereby notifying the receiver 10 of the occurrence of a fire.

  On the other hand, the receiver 10 includes a control unit 11, a display unit 12, and an acoustic unit 13. The control unit 11 in the receiver 10 identifies a warning area including the fire detector 20 in a short-circuited state by reading a change in the resistance value of the sensor line 30 with respect to the resistance value of the termination resistor 40 in a normal state. And determine that a fire has occurred in the identified alert area. Further, the control unit 11 can make an announcement via the display unit 12 and the sound unit 13 in order to notify the area where the fire has occurred. As a result, it is possible to notify the person in the building of the occurrence of the fire after identifying the area where the fire has occurred.

  Here, each fire sensor 20 in the first embodiment is configured as a multi-sensor having both gas detection and smoke (heat) detection, and external power is supplied to operate the fire sensor 20 itself. It is a technical feature that it has a configuration that does not need to be supplied from the factory. Then, next, the internal structure of the fire detector 20 having such technical features will be described in detail with reference to the drawings.

  FIG. 2 is an internal configuration diagram of the fire detector 20 applied to the fire detection system according to Embodiment 1 of the present invention. The plurality of fire detectors 20 may be mixed with other fire detectors, or all may have the same configuration.

  The fire detector 20 in the first embodiment shown in FIG. 2 includes a CO gas detector 21, a constant voltage circuit 22, a smoke detector 23, a fire signal output unit 24, a confirmation lamp 25, a fire signal output unit 24, and A control unit 26 that controls the confirmation lamp 25 is provided. In FIG. 2, the fire signal output unit 24 and the confirmation lamp 25 are illustrated as being connected in series, but may be connected in parallel.

  The CO gas detector 21 includes a gas sensor 21a arranged in series and parallel. Here, the gas sensor 21a is an electrochemical gas sensor, and can generate an electromotive force in response to CO gas generated during combustion. In the fire detector 20 according to the first embodiment, the electromotive force of the CO gas detector 21 provided in the fire detector 20 is used as the power necessary for the operation of the fire detector alone, so that the external The power supply from is unnecessary.

  For this reason, the fire detector 20 does not perform a fire detection operation in normal times, but reacts with the CO gas generated by the fire and is activated when an electromotive force is generated by the gas sensor 21a, and starts the fire detection operation.

  In addition, according to the electric energy required as the fire detector 20, the series-parallel number of the gas sensors 21a can be set appropriately. That is, the number of gas sensors 21a can be determined so that the voltage shortage is eliminated by the number of gas sensors 21a connected in series and the current shortage is eliminated by the number of gas sensors 21a connected in parallel.

Next, the principle that the gas sensor 21a generates an electromotive force in response to the CO gas generated during combustion will be briefly described. The gas sensor 21a includes a detection electrode and a counter electrode using a noble metal catalyst, and an ionic conductor sandwiched between these electrodes. When a detection target gas such as CO is present, a reaction represented by the following formula (1) occurs on the catalyst with water vapor in the air on the catalyst.
_{CO + H 2 O → CO 2} + 2H + + 2e - (1)

When the detection electrode and the counter electrode are electrically connected, protons (H ⁺ ) generated at the detection electrode reach the counter electrode via the ion conductor. On the other hand, electrons (e ⁻ ) generated simultaneously with protons reach the counter electrode via an external electric wire. On the counter electrode, a reaction of the following formula (2) occurs between protons and electrons and oxygen in the air.
(1/2) O 2 + 2H ⁺ 2e ⁻ → H ₂ O (2)

That is, the gas sensor 21a can be regarded as a battery having a gas as an active material, which is configured by the whole battery reaction represented by the following equation (3), which includes the above-described reaction equations (1) and (2).
CO + (1/2) O ₂ → CO ₂ (3)

  Therefore, it is possible to quantitatively measure the CO gas concentration by electrically connecting the detection electrode and the counter electrode and measuring the output current. In the first embodiment, the CO gas detector 21 configured by connecting the gas sensors 21a in series and parallel using the battery sensor of the gas sensor 21a is used as the power of the fire detector 20 itself. It is used as a supply source.

  Returning to the description of FIG. 2, the constant voltage circuit 22 converts the electric power generated by the CO gas detector 21 into a predetermined voltage, and controls the smoke detector 23, the fire signal output unit 24, and the confirmation lamp 25. To the unit 26.

  The smoke detector 23 is a sensing unit that senses a physical phenomenon caused by a fire, and a conventional technique can be applied. Specifically, a smoke detection unit using a light emitting element and a light receiving element of a photoelectric smoke detector can be used as the smoke detection unit 23.

  The fire signal output unit 24 is configured to have a contact output that is closed when a smoke factor is detected by the smoke detector 23.

  The confirmation lamp 25 is an indicator that is turned on when the contact output by the fire signal output unit 24 is in a closed state, and can announce the operating state to surrounding people.

  In the above description, the case where the smoke detection unit (smoke detection unit 23) using the light emitting element and the light receiving element of the photoelectric smoke detector is used as a detection unit for detecting a physical phenomenon due to a fire is described. It is also possible to use a heat sensing part using a heat sensing element such as an ion-type smoke sensor or thermistor using the heat sensing element as the sensing part.

By providing such a configuration, the fire detector and the fire detection system according to Embodiment 1 can obtain the following effects.
The power supply of the fire detector itself is realized by the battery function of the gas sensor 21a, and no external power supply is required for the fire detector. In addition, the fire detector is activated by the CO gas generated by the fire, and the fire detection operation is started. As a result, during normal times when no fire is occurring, the power consumption of the fire detector can be reduced to zero, and the restriction on the number of fire detectors connected to one receiver can be substantially eliminated.

-As an original fire detection function, in addition to smoke or heat detection, CO gas detection can be performed at the same time, and an improvement in detection accuracy by a multi-sensor can be realized with an inexpensive and compact configuration. Further, in the case of fire detection using CO gas and smoke, it is possible to detect the generation of smoke at an early stage by appropriately setting the detection sensitivities of the gas sensor 21a and the smoke detector 23.

・ By appropriately setting the number of gas sensors 21a in series and parallel according to the required power and gas detection capability, an appropriate fire detection system can be constructed according to various installation environments (monitored space) and applications. can do. Note that the gas sensor 21a is not limited to the series-parallel connection, and is configured in such a manner that the necessary power can be obtained only in series, only in parallel, or only one according to the gas detection capability. Can do.

  As described above, according to the first embodiment, the fire sensor is configured by using the gas sensor having the gas detection function and the battery function, thereby eliminating the limitation on the number of installed fire detectors. It is possible to obtain a fire detector and a fire detection system capable of improving detection accuracy by a sensor. In addition, it can be mixed with existing fire detectors, and there is no limit on the number of installations, so there is no need to review the power supply capacity, etc., and expansion to existing facilities is possible.

  DESCRIPTION OF SYMBOLS 10 Receiver, 11 Control part, 12 Display part, 13 Sound part, 20 Fire detector, 21 CO gas detector, 21a Gas sensor, 22 Constant voltage circuit, 23 Smoke detection part, 24 Fire signal output part, 25 Confirmation light, 26 Control unit.

Claims (3)

A gas detector composed of an electrochemical gas sensor that detects a carbon monoxide concentration in a monitoring target space and generates an electromotive force in accordance with the carbon monoxide concentration;
A constant voltage circuit for converting the electromotive force generated by the gas detector into a power source having a constant voltage;
A sensing unit that receives the supply of power from the constant voltage circuit and senses the occurrence of a fire by sensing a physical phenomenon due to a fire;
A fire detector comprising: a fire signal output unit configured to receive a supply of power from the constant voltage circuit and to output a contact signal to be closed when a fire is detected by the sensing unit. The gas detector includes a plurality of the electrochemical gas sensors, and is configured by connecting a plurality of electrochemical gas sensors in series in one row, in parallel in one row, or in series-parallel connection. The fire detector according to claim 1. A fire detection system comprising a receiver in which a plurality of fire detectors according to claim 1 or 2 are connected as a P-type system,
The receiver detects the fire in which the contact signal is closed by detecting the fire at the sensing unit after being activated by the CO gas generated by the fire without supplying power to the plurality of fire detectors. A fire detection system that identifies a fire detector from a change in resistance value and notifies that a fire has occurred in the specified fire detector installation area.

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