JP3005079B2 - Fire detector and fire alarm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire detector and a fire alarm system.

[0002]

2. Description of the Related Art In a conventional fire alarm system, in order to enable a receiver to detect an abnormality of a fire detector, as shown in FIG. Besides, fire detectors SE1p, SE2p, ... SEnp
An abnormality detection signal line K for sending a signal indicating that is abnormal is used.

The fire detector SE1p has a fire detector 10 for detecting a fire, a fire signal generator 20 for generating a fire signal when the fire detector 10 detects a fire, and an abnormal condition of the fire detector 10. An abnormality detection unit 30 that detects that
An abnormal signal generator 40 for generating an abnormal signal when the fire detector 10 is abnormal;
.., SEnp have the same configuration as the fire detector SE1p.

The fire signal generator 20 includes a thyristor T1 that is turned on by a signal output when the fire detector 10 detects a fire, an operation confirmation light LED1, and a confirmation light LED
Thyristor T1 having resistors R1 and R2 for protecting
And the confirmation light LED1 and the resistor R1 are connected in series.
2 is connected in parallel with the confirmation light LED1.

[0005] The abnormality detecting section 30 receives an output of a sensor in the fire detecting section 10 and determines that the fire detecting section 10 is abnormal when the level of this output is, for example, equal to or lower than a predetermined value. A signal for turning on T2 is output.

[0006] The abnormal signal generating section 40 includes the fire signal generating section 2.
0 has the same configuration as that of the fire signal generator 20 for common use, and includes a thyristor T2, an abnormality indicator LED2, and an indicator L.
The resistors R3 and R4 that protect the ED2 correspond to the thyristor T1, the confirmation light LED1, and the resistors R1 and R2, respectively. The thyristor T2 is a thyristor that is turned on when the abnormality detection unit 30 outputs a signal. The thyristor T2, the indicator LED2, and the resistor R3 are connected in series.
A resistor R4 is connected in parallel with the confirmation light LED2.

The receiver REp is provided with a comparator C for fire determination.
1. Comparator C2p for abnormality determination, comparator C for disconnection detection
3 and a reference voltage VR1p for fire determination and abnormality determination
(9V), a resistor R12 for receiving an abnormal signal, and a reference voltage VR3 (1
V), the resistors R9 and R10 and the comparators C1 and C
2, an MPU (microprocessor) 50p for processing signals from C3.

In this conventional example, when the abnormality detection signal line K is not provided (that is, when the abnormality signal
When the terminal on the opposite side is connected to the signal line)
When a fire detector becomes abnormal, the voltage of the line L decreases. At this time, even if another fire detector detects a fire and tries to lower the voltage of the line L, the voltage of the line L decreases. Since the fire has already dropped, no other fire detector can detect the fire. Further, the receiver REp cannot distinguish the fire signal from the abnormal signal. Therefore,
An abnormality detection signal line K is used in parallel with one line L (common line and signal line).

[0009]

However, in the above-described conventional apparatus, when a non-abnormality detection type fire detector (a fire detector that cannot detect an abnormality of the fire detection unit) is connected to the line L, When this non-abnormality detection type fire detector is replaced with an abnormality detection type fire detector (a fire detector that can detect an abnormality of the fire detection unit), the abnormality detection signal line K is connected to the replaced abnormality detection type fire detector. Therefore, there is a problem that the laying of the abnormality detection signal line K is complicated.

According to the present invention, an abnormality can be detected using an abnormality detection type fire detector without laying an abnormality detection signal line, and other fire detectors can normally perform fire monitoring even during abnormality detection. It is an object of the present invention to provide a fire detector and a fire alarm system that can perform the operation.

[0011]

SUMMARY OF THE INVENTION According to the present invention, when a fire detector is abnormal, a voltage which is higher than the voltage required for fire detection and which indicates an abnormality is applied to both ends of the fire detector. It is intended to be generated.

[0012]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

In this embodiment, an abnormal signal generator 60 is provided in place of the abnormal signal generator 40 in the conventional example, a receiver RE is provided in place of the receiver REp in the conventional example, and the fire detectors SE1p to SE1 in the conventional example are provided. Only the line L (signal line and common line) is connected to the fire sensors SE1 to SEn corresponding to SEnp, and the connection of the abnormality detection line K is omitted. The other circuits are the same as the circuits in the conventional example shown in FIG. The fire detectors SE2 to SEn
Have the same configuration as the fire detector SE1.

The abnormal signal generator 60 includes the abnormal signal generator 4
This is obtained by adding a resistance R to 0. In this embodiment, when the fire detector 10 is abnormal, a voltage (abnormal signal) which is higher than the voltage required for fire detection and indicates that the fire is abnormal is generated at both ends of the fire detector SE1. However, the resistor R is an example of a unit that generates a voltage having a difference between the voltage of the abnormal signal and the voltage required for fire detection.

That is, when the abnormality detection unit 30 detects an abnormality of the fire detection unit 10, the abnormality signal generation unit 60 detects another fire connected to the same line as the line to which the fire detector SE1 is connected. This is an example of an abnormal signal generating unit that generates an abnormal signal indicating that the fire can be normally detected by the sensing units SE2 to SEn and that the fire detecting unit SE1 is abnormal.

The fire signal generator 20 is an example of a means for transmitting a fire signal to a receiver by changing the voltage between both ends of the fire detector to a fire detection voltage when the fire detector detects a fire. And the fire signal generator 20
A first series circuit comprising a switching element and voltage drop means for generating a predetermined voltage at both ends when the switching element is turned on, wherein two signal lines (line L)
1 is an example of a first series circuit connected between the first and second circuits.

The abnormality detection section 30 is an example of a means for detecting that the fire detection section is abnormal. The abnormality signal generation section 60 includes a second series circuit similar to the first series circuit and a second series circuit. It comprises a second series circuit and a resistor R connected in series. Note that a Zener diode or a battery may be used instead of the resistor R. The resistance R
A new resistor having a value obtained by adding the resistance value of the resistor 3 and the resistance value of the resistor R may be used instead of the resistors R and R3.

When the thyristor T1 is turned on, the voltage between both ends of the fire signal generator 20 becomes, for example, 4.5V,
When the thyristor T2 is turned on, the values of the respective resistors and the like are set such that the voltage across the abnormal signal generator 60 becomes, for example, 16V.

FIG. 2 shows the abnormality detection unit 3 in the above embodiment.
FIG. 9 is a circuit diagram illustrating an example of a zero.

The abnormality detecting section 30 detects an abnormality of the transmitted light type smoke detector. When the dimming rate becomes lower than a predetermined value due to the contamination of the surface of the light emitting and receiving section, the abnormality detecting section 30 detects the abnormality. It outputs an abnormal signal. This abnormality detection unit 3
0 is a sampling circuit 31 that periodically (for example, once every 10 minutes) samples a signal from the light receiving sensor S in the fire detecting unit 10 and stores a plurality of output signals of the sampling circuit 31 (for example, one hour). A averaging circuit 33 for averaging the signals stored in the RAM 32 a predetermined number of times;
A D / A circuit 34 for converting the averaged value into an analog signal, and a predetermined reference value (for example, a sampling circuit 3
A reference value output circuit 35 that outputs 50% of the initial output (1), a D / A circuit 36 that converts this reference value to an analog signal, and a signal when the average value is smaller than the reference value. H ".

In the receiver RE, the resistance R5
Instead of p and R6p, resistors R5 and R6 are provided. For example, 11V is generated as a reference voltage VR1 for fire determination, and resistors R7 and R8 are provided to generate a reference voltage VR2 for abnormality determination. The series resistance of R7 and R8 is connected to the + 24V line and generates, for example, 2V as the abnormality determination reference voltage VR2. And
The-input terminal of the comparator C2 for abnormality determination has a reference voltage VR.
2 is applied, and a receiving resistor R11 is connected to its + input terminal. Other circuits in the receiver RE are the same as those in the receiver REp in the conventional example.

Next, the operation of the above embodiment will be described.

First, in the above embodiment, the fire detector S
If the signal from E1 to SEn is, for example, less than 0V to 1V, it means that the wire is broken. For example, if it is less than 1V to 2V, it means that it is normal, for example, 2V to 1V.
If it is less than 1 V, it means that the fire detecting unit 10 is abnormal. For example, if it is 11 V to 24 V, it means that a fire has occurred.

If no fire or disconnection occurs and no abnormality of the fire detector 10 occurs, the fire detectors SE1 to SE1 to S
Only a very small current flows through En and the receiving resistor R11
Is about 1.5 V, and only the comparator C3 outputs "H". Therefore, the MPU 50 is in a normal state (no fire or disconnection occurs, and no abnormality of the fire detector 10 occurs). State).

When the fire detector 10 detects a fire, a signal for turning on the thyristor T1 is sent to the fire detector 10.
Is output, the thyristor T1 is turned on, the confirmation light LED1 is turned on, and the voltage between both ends of the fire signal generation unit 20 changes to 4.5V. As a result, the voltage between both ends of the reception resistor R11 becomes about 19.5 V, and all of the comparators C1 to C3 output "H". Output.

On the other hand, when the dimming rate becomes 50% or more of the initial value due to the contamination of the light emitting and receiving unit surface of the transmitted light type smoke detector, the abnormality detecting unit 30 outputs an abnormal signal. That is, the abnormality detection unit 30 outputs a signal for turning on the thyristor T2, the thyristor T2 is turned on, and the indicator light L
As ED2 lights up, the voltage across abnormal signal generator 60 changes to 16V. Thereby, the reception resistance R1
1 is about 8 V, and only the comparators C2 and C3 output "H".
Recognizes that an abnormality has occurred, and outputs an abnormality warning signal. In this case, since 16 V is applied to both ends of the fire detector SE1, at this time, the other fire detectors SE2 to SE2 are applied.
Even if SEn detects a fire, fire detectors SE2 to SEn
Can reliably output a fire signal. In other words, at this time, if any one of the fire detectors SE2 to SEn detects a fire, the voltage between both ends of the fire detector that has detected the fire becomes 4.5 V, so that the reception resistor R connected to the line L
11 generates 19.5 V, and all of the comparators C1 to C3 output “H”, so that the MPU 50 can recognize that a fire has occurred.

That is, in the above-described embodiment, even if no fire detection line K is provided, even if any fire detector is generating an abnormality signal indicating an abnormality of the fire detection unit, other fire detection lines can be detected. The device can send a fire signal to the receiver.

If a disconnection occurs in the line L, the + inputs of the comparators C1 to C3 become 0 V.
3 output “L”, the MPU 50 can recognize that the wire is disconnected, and outputs a disconnection signal (not shown).

In the above embodiment, the fire detector 10 is a transmitted light type smoke detector, but a smoke detector other than a transmitted light type such as a scattered light type, a heat detector, or the like is used as the fire detector 10. In response to this, the abnormality detection unit 30 may detect an abnormality of a smoke sensor, a heat sensor, or the like other than the transmitted light type.

[0030]

According to the present invention, it is possible to detect an abnormality using an abnormality detection type fire detector without laying an abnormality detection signal line.

Further, according to the present invention, even if an abnormality detection signal is being transmitted, the fire monitoring capability of another fire detector on the same line connected in parallel with the detector is not lost. When the fire detection signal is transmitted, the fire detection signal is preferentially received by the receiving unit, so that the reliability of the fire notification function is not reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a circuit diagram illustrating an example of an abnormality detection unit 30 in the embodiment.

FIG. 3 is a circuit diagram showing an example of a conventional fire alarm system that can detect an abnormality of a fire detector.

[Explanation of symbols]

 SE1 to SEn: Fire detector, 10: Fire detector, 20: Fire signal generator, 30: Abnormal detector, 60: Abnormal signal generator, RE: Receiver.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G08B 17/00

Claims (2)

(57) [Claims] A fire detecting unit for detecting a fire; when the fire detecting unit detects the fire, the voltage between both ends of the fire detector is changed to a fire detection voltage, so that a fire signal is transmitted to a predetermined receiving unit. A fire signal generating unit for transmitting an alarm; an abnormality detecting unit for detecting that the fire detecting unit is abnormal; and a line to which the fire detector is connected when the abnormal detecting unit detects the abnormality. An abnormal signal generating unit that generates an abnormal signal indicating a voltage at which the other fire detecting units connected in parallel to the same line can normally detect a fire, and indicating that the fire detecting unit is abnormal. A fire detector characterized by having. 2. A fire detector for detecting a fire, and a fire signal for generating a fire signal by changing a voltage between both ends of the fire detector to a fire detection voltage when the fire detector detects the fire. A generator, an abnormality detector that detects that the fire detector is abnormal, and, when the abnormality detector detects the abnormality, a parallel connection to the same line as the line to which the fire detector is connected A voltage at which the other fire detector that is being used can normally detect fire,
A fire detector having an abnormal signal generating unit that generates an abnormal signal indicating that the fire detecting unit is abnormal; and a receiving unit that receives the fire signal and the abnormal signal from the fire sensor. A fire alarm system.