KR102075536B1 - A fire alarm apparatus and a fire monitoring decision circuit being used at the same - Google Patents

Abstract

The present invention relates to a fire monitoring apparatus. A fire monitoring apparatus comprising: a first temperature sensor for measuring whether an ambient temperature reaches a first temperature, a first temperature fuse, a first temperature sensor, and a first temperature fuse that shut off when the ambient temperature is greater than or equal to a second temperature; A first fire sensing unit including a first metal housing covering the first metal housing and two first terminals connected in series with the first temperature sensor and the first fuse and exposed to the outside of the first metal housing; A second temperature sensor that measures whether the ambient temperature reaches the first temperature, a second temperature fuse that shuts off when the ambient temperature exceeds the second temperature, a second temperature sensor, and a second metal covering the second temperature fuse A second unit installed at a predetermined distance from the first fire detection unit including a housing, a second temperature sensor and two second terminals connected in series and exposed to the outside of the second metal housing; Fire detection unit; And a fire determination circuit unit connected to the first terminal of the first fire detection unit and the second terminal of the second fire detection unit to determine whether a fire has occurred, and the fire determination circuit unit connected to the first terminal to connect the first terminal to the first terminal. It is determined whether the temperature measured by the temperature sensor reaches the first temperature, and the first interface circuit for determining whether the first temperature fuse is blocked or not, the temperature measured by the second temperature sensor in connection with the second terminal is the first temperature. A second interface circuit for determining whether a temperature is reached and determining whether the second temperature fuse is blocked, a first condition in which both the first temperature sensor and the second temperature sensor reach the first temperature, and the first temperature sensor A second condition in which a temperature is reached and the second temperature fuse is cut off, a third condition in which the second temperature sensor reaches the first temperature and the first temperature fuse is cut off, and a first temperature fuse and a second temperature fuse If any one of the blocked fourth conditions is met, And a fire alarm output circuit unit operable to output a re-alarm.

Description

Fire alarm apparatus and a fire monitoring decision circuit being used at the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire monitoring apparatus for a production system or building such as semiconductor, electronics, automobile, shipbuilding, steel, chemical industry, and fire monitoring circuit used in the fire monitoring apparatus.

In production lines in industries such as automobiles, shipbuilding, and electronics, a fire monitoring system is essential to protect the facilities and lives used in the production system.

Conventional fire alarms use a thermistor whose resistance changes as the temperature changes, and a bimetal that corresponds to a mechanical switch that cuts or connects the circuit when the ambient temperature rises above a certain temperature. A fire monitoring device is used.

However, in the conventional fire alarm system, if the temperature sensor or the bimetal malfunctions, a false alarm may be generated, and a malfunction of the fire alarm device may be caused by a malfunction of the fire alarm device, especially in a semiconductor production line. If blocked for a certain period of time, not only the waste of silicon wafers and expensive semiconductor production resources put into the production line, but also serious production degradation due to the setup work for restarting the stopped production process.

 It is an object of the present invention to provide a fire monitoring device that significantly reduces malfunctions.

Still another object of the present invention is to provide a fire monitoring circuit having excellent fire monitoring capability to minimize the malfunction rate of the fire monitoring device.

The present invention for achieving the object as described above, in the fire monitoring device, the first temperature sensor for measuring whether the ambient temperature reaches the first temperature, the first blocking for blocking when the ambient temperature is more than the second temperature A first temperature fuse, a first metal housing covering the first temperature sensor and the first temperature fuse, and two first connecting the first temperature sensor and the first fuse in series and exposed to the outside of the first metal housing A first fire detection unit comprising one terminal; A second temperature sensor for measuring whether an ambient temperature reaches the first temperature, and covering a second temperature fuse, the second temperature sensor, and the second temperature fuse which shut off when the ambient temperature becomes higher than the second temperature. A position spaced apart from the first fire sensing unit including a second metal housing and two second terminals connected in series with the second temperature sensor and the second temperature fuse and exposed to the outside of the second metal housing; A second fire detection unit installed at the; And a fire determination circuit unit connected to the first terminal of the first fire detection unit and the second terminal of the second fire detection unit to determine whether a fire has occurred, wherein the fire determination circuit unit is connected to the first terminal. The first interface circuit for determining whether the temperature measured by the first temperature sensor reaches the first temperature and determining whether the first temperature fuse is blocked, the second temperature sensor connected to the second terminal A second interface circuit for determining whether the measured temperature reaches the first temperature and determining whether the second temperature fuse is blocked, and both the first temperature sensor and the second temperature sensor reach the first temperature In a first condition, the second condition in which the first temperature sensor reaches the first temperature and the second temperature fuse is cut off, the second temperature sensor reaches the first temperature and the first temperature fuse is shut off. Third condition It characterized in that it comprises a first temperature fuse and the fire signal output circuit to the second temperature when the fuse is cut off both the fourth condition of any one condition is met during the operation to output a fire signal. The fire monitoring device of the present invention installs two fire monitoring units spaced apart from each other by a predetermined distance, and all of the temperature sensors of the two fire monitoring units have a predetermined temperature or more, or both temperature fuses are short-circuited, or two temperature If one of the sensors shorts above the reference temperature and the other fuse shorts, a fire alarm is issued to significantly reduce the possibility of malfunction.

The first interface circuit includes a first temperature sensor comparison circuit comparing the voltage output from the first temperature sensor with a predetermined reference voltage and a first temperature fuse blocking circuit for determining whether the first temperature fuse is blocked. The second interface circuit may include a second temperature sensor blocking circuit configured to compare the voltage output from the second temperature sensor with a predetermined reference voltage and determine whether the second temperature fuse is blocked. Characterized in that it comprises a.

The fire determination circuit unit is characterized by consisting of a memory for storing a program and a control unit for executing a program stored in the memory.

An object of the present invention described above is another aspect of the present invention, in the fire determination circuit unit connected to the first fire detection unit and the second fire detection unit each having at least one temperature sensor to determine whether a fire occurs, the A first interface circuit connected to the first fire detection unit to determine whether the temperature measured by the temperature sensor inside the first fire detection unit reaches the first temperature, and to determine whether the first fire detection unit is disconnected; A second interface circuit connected to the second fire detection unit to determine whether the temperature measured by the temperature sensor inside the second fire detection unit reaches the first temperature and to determine whether the second fire detection unit is disconnected; And a first condition in which both the temperature sensor of the first fire detection unit and the temperature sensor of the second fire detection unit reach the first temperature, the temperature sensor of the first fire detection unit reaches the first temperature and the second temperature is reached. The second condition in which the fire detection unit is disconnected, the third condition in which the temperature sensor of the second fire detection unit reaches the first temperature and the first fire detection unit is disconnected, and the first fire detection unit and the second fire detection unit It is also achieved through a fire determination circuit unit comprising a fire alarm output circuit unit operable to output a fire alarm if any one of the fourth conditions, which are all disconnected, is satisfied.

The fire alarm market according to the present invention having the configuration as described above can provide a fire monitoring device that significantly reduces the possibility of malfunction.

The fire judging circuit portion of the present invention significantly reduces the malfunction of the fire monitoring apparatus, and as a result, a production system such as a semiconductor line has an effect of improving production efficiency.

1 is a block diagram of a fire monitoring apparatus according to the present invention.
2 is a block diagram of a fire determination circuit unit according to the present invention.
3 is a flowchart showing a condition for issuing a fire alarm of the fire determination circuit unit according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. The features and advantages of the present invention will become more apparent from the description of the preferred embodiment based on the accompanying drawings.

1 is a block diagram of a fire monitoring apparatus according to the present invention.

The fire monitoring apparatus 100 according to the present invention includes a first fire detection unit 10, a second fire detection unit 20, and a fire determination circuit unit 30.

The first fire detection unit 10 and the second fire detection unit 20 are installed at a predetermined distance from each other, and the first terminals 11a and 11b and the second fire detection unit of the first fire detection unit 10 are installed. The second terminals 21a and 21b of the 20 are connected to the fire determination circuit unit 30, respectively.

The first fire detection unit 10 and the second fire detection unit 20 are connected to the metal coupling socket 40, and the metal coupling socket 40 has the first terminals 11a and 11b and the second terminal 21a. , 21b) is connected to the fire determination circuit unit (30).

The first fire detection unit 10 includes a first metal housing 12, a first temperature sensor 13, a first temperature fuse TF1 and 14, and a first wire 15.

The first temperature sensor 13 and the first temperature fuses TF1 and 14 are connected in series by the first wire 15 and are connected to the fire determination circuit unit 30 through the first terminals 11a and 11b.

The first metal housing 12 covers the first temperature sensor 13, the first fuses TF1 and 14, and the first wire 15 that are built therein, and protects the sensors, the fuses, and the wires therein. The size and size of the first metal housing 12 can be manufactured in various forms.

The first temperature sensor 13 changes the resistance value according to the external temperature, and the first fuses TF1 and 14 short the external temperature when the temperature exceeds the predetermined temperature. The short circuit of the present invention means that the circuit fuse is cut off by the thermal fuse.

The fire determination circuit unit 30 is connected to the first temperature sensor 13 and the first temperature fuses TF1 and 14 to detect a temperature by measuring a change in the resistance value of the first temperature sensor 13. Detects the disconnection of 1 temperature fuse (TF1, 14) and detects exposure to the environment above the critical temperature.

The second fire detection unit 20 includes a second metal housing 22, a second temperature sensor 23, second temperature fuses TF2 and 24, and a second wire 25.

The second temperature sensor 23 and the second fuses TF2 and 24 are connected in series by the second wire 25 and are connected to the fire determination circuit unit 30 through the second terminals 21a and 21b.

The second metal housing 22 covers the second temperature sensor 23, the second temperature fuses TF2 and 24, and the second electric wire 25 to protect the internal sensors, the fuses, and the electric wires.

The second temperature sensor 23 changes its resistance value according to the external temperature, and the second temperature fuses TF2 and 24 short-circuit the same when the external temperature reaches a predetermined temperature.

The fire determination circuit unit 30 is connected to the second temperature sensor 23 and the second temperature fuses TF2 and 24 to measure the variation of the resistance of the second temperature sensor 23 to detect the ambient temperature. The short circuit of the second temperature fuses TF2 and 24 determines whether the temperature is equal to or greater than the threshold temperature.

Fire determination circuit unit 30 of the present invention has the effect of more than simply using two fire detection unit (10,20).

If there is only one fire detection unit (10 or 20), depending on the characteristics of each temperature sensor and the temperature fuse, a slight deviation occurs in the resistance value and the temperature difference, and as a deviation of the threshold temperature for detecting the fire by this deviation There is a possibility of malfunction of the fire alarm.

The present invention uses two fire detection units (10, 20), the first temperature sensor 13, the second temperature sensor 23, each of the fire detection unit (10, 20) (first temperature fuse ( It is possible to issue a more precise fire alarm by combining the state of the detection temperature and the short circuit of the TF1, 14) and the second temperature fuse TF2, 24.

Preferred embodiments of the present invention have two fire detection units 10 and 20, but the present invention is not limited thereto. The case of having three or four fire detection parts is also included in this invention.

On the other hand, in the production system equipped with the fire monitoring apparatus of the present invention, for example, in the case of a semiconductor production line, one fire monitoring device should be provided at a predetermined distance of the production line, and in some cases, a semiconductor factory of one floor 1,000 fire monitors are installed in the production facility, and each of these 1,000 fire monitors independently judges the fire and issues an alarm. This is because fires occur by region, and the purpose of the fire monitoring system is to detect the fire early and to suppress the fire.

Therefore, it is important that the fire monitoring command without malfunction of each fire monitoring device. If 1,000 fire surveillance devices with a 1% chance of malfunction are installed, the probability of malfunction will be 1000%, making the fire surveillance apparatus impossible to use.

Bimetals used in the prior art are mechanical materials switches that are shut off and reconnected at a given temperature, with a typical malfunction rate of 1%. Therefore, these bimetal fire alarms are difficult to use in semiconductor lines.

Like the present invention, the fire alarm is issued through one fire judging circuit unit having a semiconductor temperature sensor and a semiconductor temperature fuse respectively embedded in the fire monitoring unit and determining the output of the plurality of fire detection units, thereby significantly reducing the malfunction rate.

A detailed description of the fire determination circuit unit 30 will be given regarding the fire alarm command without precise malfunction of the present invention.

2 is a block diagram of a fire determination circuit unit according to the present invention.

The fire determination circuit unit 30 according to the present invention includes a first interface circuit 33, a second interface circuit 36, a fire alarm output circuit unit 39, and an alarm output terminal 39a.

The first interface circuit 33 is connected to the first terminals 11a and 11b of the first fire detection unit 10 to connect the first temperature sensor 13 and the first fuse TF1 of the first fire detection unit 10. Interface (14).

More specifically, the first interface circuit 33 includes a first temperature sensor temperature comparison path 31 and a first temperature fuse cutoff circuit 32.

The first temperature sensor temperature comparator 31 is a circuit that receives a resistance value changed according to the ambient temperature output from the first temperature sensor 13 and compares it with a reference temperature.

For example, when the ambient temperature reaches 70 degrees Celsius, the first temperature sensor 13 outputs a resistance value corresponding to the temperature corresponding to 70 degrees Celsius, and the first temperature sensor temperature comparison furnace 31 The trigger signal is output when the ambient temperature of the first temperature sensor reaches 70 degrees Celsius.

The first temperature fuse blocking circuit 32 corresponds to a circuit for determining whether the first fuses TF1 and 14 are blocked. The first temperature fuses TF1 and 14 use elements which are blocked at 120 degrees Celsius, 150 degrees or 240 degrees Celsius, for example. All temperature fuses are shut off within 0.1% of rated temperature.

When the first temperature fuses TF1 and 14 are blocked by the influence of any ambient temperature, the first temperature fuse blocking circuit 32 outputs a state signal indicating that the first fuses TF1 and 14 are blocked.

The second interface circuit 36 is connected to the second terminals 21a and 21b of the second fire detection unit 20 to connect the second temperature sensor 23 and the second temperature fuse of the second fire detection unit 20. The sensing signal of TF2, 24 is interfaced.

The second interface circuit 36 includes a second temperature sensor temperature comparison circuit 34 and a second temperature fuse cutoff circuit 35.

The second temperature sensor temperature comparator 34 is a circuit that receives the resistance value changed according to the ambient temperature output from the second temperature sensor 23 and compares it with the reference temperature. For example, when the ambient temperature reaches 70 degrees Celsius, the second temperature sensor 23 outputs a resistance value corresponding to the temperature corresponding to this 70 degrees Celsius, and the second temperature sensor temperature comparison furnace 34 is 2 When the ambient temperature of the temperature sensor 23 reaches 70 degrees Celsius, it outputs an active signal.

The second temperature fuse cutoff circuit 35 is a circuit for determining whether the second fuses TF2 and 24 are blocked or normal. For example, the second temperature fuses TF2 and 24 use elements that are cut off at 120 degrees Celsius, 150 degrees Celsius, or 240 degrees Celsius.

If the second temperature fuse TFT 24 is blocked by the influence of any ambient temperature, the second temperature fuse cutoff circuit 35 outputs a state signal indicating that the second temperature fuse TF 2, 24 is blocked.

The fire alarm output circuit unit 39 of the present invention includes a fire alarm judgment circuit 37 and a fire alarm condition storage circuit 38.

The fire alarm judgment circuit 37 is connected to the first temperature sensor temperature comparison circuit 31 and the first temperature fuse cutoff circuit 32 of the first interface circuit 33, and the first temperature sensor temperature comparison circuit 31 The first temperature sensor 13 determines whether the temperature measured by the first temperature sensor 13 is greater than or equal to a predetermined temperature and whether the first temperature fuses TF1 and 14 are short-circuited from the first temperature fuse blocking circuit 32. The predetermined temperature corresponds to the first temperature and may be set, for example, to 70 degrees Celsius.

The fire alarm judgment circuit 37 is connected to the second temperature sensor temperature comparison circuit 34 and the second temperature fuse cutoff circuit 35 of the second interface circuit 36, and the second temperature sensor temperature comparison circuit 34 Receives a status signal indicating whether the temperature measured by the second temperature sensor 23 is greater than or equal to a predetermined temperature and whether the second temperature fuse TF2 or 24 is short-circuited from the second temperature fuse cutoff circuit 35. . Likewise, the predetermined temperature corresponds to the first temperature and may be set, for example, 70 degrees Celsius.

The fire alarm determination circuit 37 issues a fire alarm to the first condition that the temperature measured by the first temperature sensor 13 and the second temperature sensor 23 is both above a predetermined temperature (for example, 70 degrees or more). do.

The fire alarm judgment circuit 37 has a second condition in which the temperature measured by the first temperature sensor 13 is equal to or higher than a predetermined temperature (for example, 70 degrees or higher), and the second temperature fuse TF2, 24 is a short circuit. Issue a fire alarm.

The fire alarm judgment circuit 37 has a third condition in which the temperature measured by the second temperature sensor 23 is equal to or higher than a predetermined temperature (for example, 70 degrees or higher), and the first temperature fuse TF1, 14 is a short circuit. Issue a fire alarm.

The fire alarm judgment circuit 37 issues a fire alarm to the fourth condition in which both the first temperature fuses TF1 and 14 and the second temperature fuses TF2 and 24 are short-circuited.

The first temperature fuses TF1 and 14 and the second temperature fuses TF2 and 24 may be mounted by selecting, for example, a semiconductor temperature fuse having a short circuit at 120 degrees, 140 degrees, or 240 degrees.

In this case, a short circuit between the first temperature fuses FT1 and 14 and the second temperature fuses FT2 and 24 is shorted at 120 degrees, for example, and the first temperature sensor 13 and Even if both of the second temperature sensors 23 fail to detect a predetermined temperature of 70 degrees due to an error in the measurement, if both fuses are short-circuited, it is determined that an emergency state such as a fire is alarmed.

As a result, the fire alarm determination circuit 37 outputs an active signal for the fire alarm in all four cases as described above and outputs this active output signal to the outside through the alarm output terminal 39a.

Outside the fire monitoring device 100 of the present invention, a server (not shown) or a management computer (not shown) for comprehensively determining and managing a production process is installed, and responds to a fire alarm signal of the fire monitoring device 100. Emergency measures can be taken such as power cut off, emergency bell, fire alarm alert, fire call, and fire station emergency letter.

On the other hand, the fire alarm condition storage circuit 38 can further diversify the conditions for issuing a fire alarm in the above embodiment.

An embodiment of the present invention is the fire determination circuit unit 30, the first sensor temperature comparison circuit 31, the first fuse blocking circuit 32, the first interface circuit 33, the second sensor temperature comparison circuit 34 The second fuse blocking circuit 35, the second interface circuit 36, the fire alarm judgment circuit 37, the fire alarm condition storing circuit 38, and the fire alarm output circuit unit 39 are all analogs such as comparators. It is possible to design a circuit to issue a fire alarm.

Another embodiment of the present invention is the fire determination circuit unit 30, the first sensor temperature comparison circuit 31, the first fuse blocking circuit 32, the first interface circuit 33, the second sensor temperature comparison circuit 34 ), The second fuse cutoff circuit 35, the second interface circuit 36, the fire alarm judgment circuit 37, the fire alarm condition storage circuit 38, and the fire alarm output circuit section 39 is an analog circuit. It is also possible to design by using, the fire alarm judging circuit 37 is composed of a control unit, the fire alarm condition storage circuit 38 may be designed as a digital circuit consisting of a memory incorporating a program.

Accordingly, the present invention includes both analog circuits and digital circuits.

3 is a flowchart showing a condition for issuing a fire alarm of the fire determination circuit unit according to the present invention.

The fire determination circuit unit 30 measures the temperature of the first temperature sensor 13. (S10)

The fire determination circuit unit 30 measures the temperature of the second temperature sensor 23. (S20)

The fire determination circuit unit 30 detects whether the first temperature fuses TF1 and 14 are shorted. (S30)

The fire determination circuit unit 30 detects whether the second temperature fuses TF2 and 24 are shorted. (S30)

The fire determination circuit unit 30 determines whether the temperatures of the first temperature sensor 13 and the second temperature sensor 23 are all 70 degrees Celsius or more corresponding to the first temperature. (S50)

If the temperature of the first temperature sensor 13 and the second temperature sensor 23 are both 70 degrees Celsius or more, the fire determination circuit unit issues a fire alarm. (S110)

It is determined whether both the first temperature fuse TF1 and 14 and the second temperature fuse TF2 and 24 are short-circuited. (S60)

For example, if the first temperature fuse TF1, 14 and the second temperature fuse TF2, 24 are selected to be cut off at 120 degrees, the fire is judged to be blocked at 120 degrees or more, the second temperature. The circuit unit issues a fire alarm. (S110)

In the case of both NO in S50 and S60, it is determined whether the first temperature sensor 13 is greater than or equal to the first temperature and the second temperature fuses TF2 and 24 are blocked. (S70, S80)

When the first temperature sensor 13 is above the first temperature and the second temperature fuses TF2 and 24 are shut off, a fire alarm is also issued. (S110)

In the case of “NO” in step S70, it is determined whether the second temperature sensor 23 is greater than or equal to the first temperature and the first temperature fuses TF1 and 14 are blocked. (S90, S100)

When the second temperature sensor 23 is equal to or greater than the first temperature and the first temperature fuses TF1 and 14 are blocked, a fire alarm is issued. (S110)

The present invention discloses by way of example one fire determination circuit having two fire detection units, but the present invention is not limited thereto.

It is also included in the present invention that one or more fire determination circuits determine three or four fire detection units.

The present invention discloses an embodiment consisting of a temperature sensor, a temperature fuse, and an electric wire connected in series in the metal housing in one fire detection unit, but the present invention is not limited to this embodiment.

It is also included in the present invention that a temperature sensor is soldered to the circuit board replacing the electric wire to detect the ambient temperature, and the solder is shorted at a high temperature.

The present invention uses a temperature sensor and a temperature fuse each having a defective rate of 0.1%, so that an alarm is issued when both temperature sensors or temperature fuses are above the first temperature or shut off, so that theoretically 0.1% X 0.1% = Since a failure rate of 1 / 1,000,000 is obtained, it is possible to provide a fire detection apparatus having a failure rate (malfunction rate) of 1 PPM level.

In addition, since the fire alarm market value of the present invention has a malfunction rate of 1 PPM level, if 1,000 fire monitor devices of the present invention are installed in a semiconductor production system, the malfunction rate of the fire monitor as a whole has a precision of 1 / 1,000. Therefore, it is suitable as a fire monitoring device used in semiconductor production equipment.

100: fire monitoring device
10: First Fire Detection Department
11a, 11b: First terminal
12: first metal housing
13: first temperature sensor
14: 1st temperature fuse, TF1
15: first wire
20: Second Fire Detection Department
21a, 21b: Second terminal
22: second metal housing
23: second temperature sensor
24: 2nd fuse, TF2
25: second wire
30: fire judgment circuit
31: first temperature sensor temperature comparison furnace
32: first temperature fuse blocking circuit
33: first interface circuit
34: second temperature sensor temperature comparison furnace
35: second temperature fuse blocking circuit
36: second interface circuit
37: fire alarm judgment circuit
38: fire alarm condition storage circuit
39: fire alarm output circuit
39a: Alarm output terminal
40: metal bonding socket

Claims (4)

In the fire monitoring apparatus,
A first temperature sensor for measuring whether the ambient temperature reaches the first temperature, a first temperature fuse to shut off when the ambient temperature is greater than or equal to the second temperature, and a first temperature sensor to cover the first temperature sensor and the first temperature fuse A first fire sensing unit comprising a first metal housing and two first terminals connected in series with the first temperature sensor and the first temperature fuse and exposed to the outside of the first metal housing;
A second temperature sensor for measuring whether an ambient temperature reaches the first temperature, and covering a second temperature fuse, the second temperature sensor, and the second temperature fuse to shut off when the ambient temperature is greater than or equal to the second temperature. A position spaced apart from the first fire sensing unit including a second metal housing and two second terminals connected in series with the second temperature sensor and the second temperature fuse and exposed to the outside of the second metal housing; A second fire detection unit installed at the; And
A fire determination circuit unit connected to the first terminal of the first fire detection unit and the second terminal of the second fire detection unit to determine whether a fire has occurred;
The fire determination circuit unit,
A first interface circuit connected to the first terminal to determine whether the temperature measured by the first temperature sensor reaches the first temperature, and to determine whether the first temperature fuse is blocked;
A second interface circuit connected to the second terminal to determine whether the temperature measured by the second temperature sensor reaches the first temperature, and to determine whether the second temperature fuse is blocked;
A first condition in which both the first temperature sensor and the second temperature sensor reach the first temperature, a second condition in which the first temperature sensor reaches the first temperature and the second temperature fuse is cut off; If a third temperature sensor reaches the first temperature and the third condition that the first temperature fuse is cut off and the fourth condition that both the first temperature fuse and the second temperature fuse are cut off are met, a fire occurs. A fire alarm output circuit unit operable to output an alarm;
The first interface circuit may include a first temperature sensor cutoff circuit for determining whether the first temperature sensor is blocked and the first temperature sensor temperature comparator comparing the voltage output from the first temperature sensor with a predetermined reference voltage. Including,
The second interface circuit may include a second temperature sensor cutoff circuit for determining whether the second temperature fuse is blocked and a second temperature sensor temperature comparator comparing the voltage output from the second temperature sensor with a predetermined reference voltage. Include,
The fire judging circuit unit comprises a memory for storing a program and a control unit for executing a program stored in the memory.
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