JPS63314697A - Fire alarm system - Google Patents

Abstract

PURPOSE:To surely attain alarm of fire breakout by providing smoke sensors giving an output of a detection signal in response to the smoke density and a receiver discriminating it as a fire and raising an alarm in sensing that the detected smoke density by a smoke sensor exceeds a set smoke detection density and the state is consecutive for a set time. CONSTITUTION:When a level detection circuit connected to smoke sensors 2, 3a giving a detection signal output in response to the smoke density via a signal circuit line (l) discriminates it as fire breakout when the detected smoke density by the smoke sensors 2, 3a exceeds a set density and the state is consecutive for a set time through the detection of the level detection circuit. Moreover, a pre-alarm means 31 of the receiver 1 raises a warning when the means 31 senses it that a pre-alarm density et lower than the setting density exceeds the smoke detection density and it is consecutive for a prescribed time or the total time when the setting detection density is exceeded is a prescribed time or over. Thus, fire breakout is surely alarmed.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fire alarm system.

[Conventional technology]

In conventional automatic fire alarm systems, when one of the multiple smoke detectors or other detectors turns on, line current flows through the signal line and the receiving MP? 1 relay operates, and its output contact operates the bell, indicator, etc.

[Problem to be solved by the invention]

However, in such a conventional example, in the case of a sensor such as a smoke sensor, the smoke detection concentration at which the sensor is turned on is set to a certain level, so there is a risk of malfunction depending on the installation location. In other words, it may detect smoke from smoking and issue a false alarm in places such as meeting rooms where a large number of people gather, or it may also issue false alarms in places where there is a heat source and is likely to generate smoke, such as a kitchen. There was fear. In particular, when the system is linked to a smoke prevention device, etc., the post-processing caused by false alarms is difficult. Therefore, there are many cases where automatic fire alarm systems are turned off at night due to the fear of such false alarms, and as a result, even if a fire actually occurs, it cannot be detected, resulting in a large number of casualties. This led to very frightening results. The purpose of the present invention is to provide a fire alarm system that can set the sensitivity of fire detection according to the combination of the detected smoke concentration and the time function, thereby making it possible to set the sensitivity according to the situation such as the installation location and improving the reliability. is to provide.

[Means to solve the problem]

The present invention includes a smoke detector that outputs a detection signal corresponding to smoke concentration, and a smoke detector that is connected to the smoke detector via a signal line to detect when the smoke concentration detected by the smoke detector exceeds a set concentration and continues for a set time. A fire determination means that determines a fire when detected, and detects that the detected smoke concentration exceeds a pre-alarm concentration that is set lower than the set concentration and continues for a predetermined time, or that the total amount of time that the detected smoke concentration exceeds the set detection concentration is determined. The device is equipped with a receiver having a pre-alarm means that issues a caution warning when it detects that a predetermined period of time has elapsed.

[Effect]

Since the present invention is configured as described above, there is less risk of malfunction due to temporary smoke generation or external disturbances, compared to conventional systems in which sensitivity is determined only by smoke concentration.
As a result, there are no false alarms and high reliability is obtained, and there is no need to use the system incorrectly, such as shutting down the system due to fear of false alarms, and it is possible to reliably warn of the occurrence of a fire. As a result, no fire actually occurs, and in the case of a false alarm, it can be used as a reference for setting the sensitivity, and each smoke detector can be adjusted to the optimum sensitivity according to the installation condition. Can be set.

[Disclosure of the invention]

The present invention will be explained below with reference to Examples. FIG. 1 shows a basic schematic configuration diagram of an embodiment, in which signals derived from a receiver 1 are connected to an intelligence type smoke detector 2, a general type smoke detector 3a, and a heat sensor 3b. Connect them in a mixed manner. The receiver 1 superimposes a transmission signal Vs consisting of a pulse code signal including an address signal individually assigned to each intelligence type smoke detector 2 on the line voltage or current of the signal line l as shown in FIG. The information sent cyclically in sequence and sent as a return signal from each called intelligence type smoke detector 2 is judged, and the signal line! By monitoring the level of the line voltage and line current, various control operations such as receiving the level signal L from the general smoke detector 3a or the general heat sensor 3b can be performed. The intelligence type smoke detector 2 can have its own address set, and the transmission signal ■s sent from the receiving IR 1
When the address signal included in the address signal matches the self-set address, various information is superimposed and sent back to the receiver 1 as a pulse code signal during the return period provided between the transmission signal VS and the next transmission signal Vs. It has become. When the general type smoke detector 3a or heat sensor 3b detects a predetermined smoke concentration or temperature, it turns on and connects the signal port a1 through an appropriate resistance.
is short-circuited, the line current or line voltage level is changed, and a fire detection signal is transmitted to the receiver 1 as a level signal vL. Therefore, at normal times, the receiver 1 sequentially calls each intelligence-type smoke detector 2, receives information from each intelligence-type smoke detector 2, and makes judgments, and also detects the voltage or current level of the signal line l. By monitoring the operation of the general type smoke detector 3a or heat sensor 3b, and detecting the steady line voltage or line current by the terminator 4 such as the resistance of the signal line l, a short circuit of the signal line i is detected. , to monitor for disconnections. Next, the specific configurations of the receiver 1 and the intelligence type smoke detector 2 will be explained. As shown in the 3rd U;4, the receiver 1 is composed of a basic unit IA and an extension unit) IB, and the extension units) IB are combined as necessary. The basic unit γ) IA uses the coupling circuit section 5 for interfacing with the signal port me, and from the line voltage extracted by the coupling circuit section 5, the level signals ■ of the general type sensors 3a and 3b, short circuits, and disconnections. and demodulates the pulse code signal, which is the return signal received and extracted via the coupling circuit section 5, and outputs the pulse code signal to the signal port MP via the coupling circuit section 5. The transmission signal modulation/demodulation circuit section 7 modulates and creates the transmission signal Vs to be superimposed, and the level detection information discriminated by the level detection circuit section 6 is decoded from the transmission signal modulation/demodulation circuit section 7 (111!). The information from the intelligent smoke detector 2 can be read to determine the occurrence of a fire, or to identify the location of a fire, and also to determine the occurrence of a disconnection or short circuit in the signal line P. It has the function of determining abnormality of the sensor 2, and based on these determination results, it can display the fire area corresponding to the signal line through the I10 interface 11, issue a fire alarm, issue a warning, and notify the area! Fi1. It generates control outputs such as sensor abnormality display, signal line abnormality display, and control of smoke prevention equipment and fire extinguishing equipment, and also sends and receives information to and from the expansion unit (IB) through the interface 9. An arithmetic signal processing circuit unit 8 consisting of a CPU, etc. that performs control and signal processing such as creating a pulse code signal for calling the device 2 and sending it to the transmission signal modulation/demodulation circuit unit 7; and a control operation of the arithmetic signal processing circuit unit 8. It is composed of a storage section 10 that stores and holds the setting contents, a keyboard 12, and the like. On the other hand, the expansion unit (IB) can send and receive data to and from the basic unit IA via the interface 13, and is a combination table of prescribed sensors and corresponding external equipment such as fire extinguishing equipment and smoke prevention equipment. and a storage unit 14 which stores combination data for setting the combination of the relay means and the number of the signal exit me to which it belongs when a relay means is provided; Selection control of the smoke prevention device etc. to be controlled from the setting contents of section 14, display of the operating state of each sensor, display of the operating state of the relay means by displaying the number of signal port #iI corresponding to the relay means, and furthermore A control operation that performs interlocking displays that display the operating status of fire extinguishing equipment, smoke prevention equipment, etc., and a keyboard 15
an arithmetic signal processing circuit section 16 that performs a series of control/signal processing such as controlling the smoke prevention device, etc. using manual commands from the computer, inputting monitoring data of the operating status of the smoke prevention device, etc.; and a keyboard 15 and a display section. 17 and an arithmetic signal processing circuit section 16, it is equipped with an I10 interface 18 that interfaces the arithmetic signal processing circuit section 16 and the selection control data of smoke prevention equipment, etc.
The basic unit IA generates a control output for a smoke prevention device, etc. Of course, the control of the smoke prevention device and the like may be performed on the expansion unit (IB) side. 13' is an interface for connecting another expansion unit (IB). As shown in FIG. 4, the intelligence type smoke detector 2 has a body section composed of a base 2a and a head 2b, and has an internal circuit as shown in FIG. 5. In other words, is there a light beam smoke detection system inside the head 2b that detects smoke?
FS 19 and the zero level shift circuit section 2o that constantly detects the zero level of the smoke detection section 19 and shifts it to stabilize the zero level. The output circuit section 21 that outputs the output, the self-check circuit section 23 that detects whether the range in which the zero level is shifted by the zero level shift circuit section 20 exceeds a predetermined range, and the self-check circuit section 23 are configured as described above. The base 2a is equipped with a function stoppage determination circuit section 22 that determines that the function has stopped and generates an H'' signal when a detection signal indicating that the predetermined range has been exceeded is output.On the other hand, the base 2a is connected to the above-mentioned helad 2b (removably). When installed, it supplies power to the circuit inside the head 2b and connects the output of the output circuit section 21 and the output of the malfunction determination circuit section 22. It is installed on a mounting surface such as a ceiling surface, and there is no internal is a level discrimination circuit section 24 that discriminates the analog signal from the output circuit section 21 into, for example, three stages and outputs three stages of smoke density data, and output data from the level discrimination circuit section 24 and the above-mentioned function stop determination circuit section 22. It takes in the information, sends it back to the receiver 1, creates a return signal consisting of a pulse code signal based on the information, and receives it via the address set in the address setting section 25 and the signal @1. When the address signal included in the transmission signal (2) transmitted from R1 matches, the information from the receiver 1 included in the transmission signal (2) is acquired, and in the return period that follows the transmission signal (2). The arithmetic signal processing circuit section 26 that performs signal processing such as sending out the return signal is coupled to the signal line l to extract the transmission signal Vs or to superimpose the return signal on the signal line! When power is obtained through the coupling circuit section 27 and the coupling circuit section 27, and the level discrimination of the level discriminator circuit section 24 described above continues for a predetermined period of time at a high smoke density setting level, that is, low sensitivity detection, the same ml of signal is output as appropriate. 7 for short-circuiting through a resistor and changing the line voltage level, current level, impedance, etc., and sending the level signal L through the coupling circuit section 27, similar to the general smoke detector 3a and heat sensor 3b.
If the smoke detector is made to function as an intelligence type, or if it outputs only a level signal similar to a general type sensor, and when it outputs a level signal, that is, when a fire is detected, 8 as a so-called point address type that transmits the pulse code signal corresponding to the address to the receiver 1! It is equipped with a type/application setting section 29 for selecting and setting whether to enable the smoke concentration, and the above-mentioned three-stage smoke concentration discrimination corresponds to type 1, type 2, and type 3 of smoke detectors, for example, 5%. , 10% and 15%, and corresponding detection signals are generated. Now, in reception W11, the following operating conditions can be set in the storage section 10 using the keyboard 12. First of all, in this system, fire occurrence determination is performed based on a combination of the smoke density from the intelligent smoke detector 2 and a time function in addition to the level signals 1 from the general smoke detector 3a and heat sensor 3b. On the receiver 1 side, the detected smoke concentration, which is a condition for determining the occurrence of a fire, and the m-stop time of the detected smoke concentration can be selected and set for each intelligence type smoke detector 2 from the keyboard 12. In other words, there are three levels of detected smoke concentration data returned from the intelligence type smoke detector 2, and two types of time, for example 6 seconds and 30 seconds, and one of these detected smoke concentrations and one of the times. The sensitivity of fire occurrence can be set using two functions: smoke concentration and time. This setting condition is for each intelligence type f! It is determined by the setting location of the A sensor 2. In addition, the receiver 1 has multiple intelligence type smoke detectors 2.
It is equipped with a logical product light N function that generates a control output to control smoke prevention equipment, fire extinguishing equipment, etc. only when the fire occurrence judgment conditions are reached, and intelligence is used to issue a logical product alarm. The combined address table of the type smoke detector 2 can be set and stored in the storage section 10 using the keyboard 12. Furthermore, the receiver 8!1 is capable of issuing a warning requiring attention, and an address table in which each intelligence type smoke detector 2 that requires a warning requiring attention is selected is stored in the memory 1 using the keyboard 12.
It is possible to store the setting to 0. As shown in FIG. 2, the receiver 1 superimposes the transmission signal Vs on the line voltage or current of the signal line 2 in the address order set by the storage unit 10 as shown in FIG. The smoke detectors 2 are called and the information on the detected smoke concentration and the monitoring information on the malfunction of each smoke detector 19 are sent from each smoke detector 2 as a return signal, and the status of each intelligence type smoke detector 2 is monitored. Check it. Now, when the reception 8!1 receives the return signal from the intelligence type smoke detector 2 at the predetermined address, the arithmetic signal processing circuit unit 8 stores it in the storage unit 10 and determines the occurrence of a fire in the intelligence type smoke detector 2. The detected smoke concentration for the return signal is compared with the detected smoke concentration data in the return signal, and if the detected smoke concentration data is smaller than the set detected smoke concentration, the arithmetic signal processing circuit section 8 determines that no fire has occurred. . On the other hand, if the smoke concentration is higher than the detected smoke concentration, the set time is counted by the fire determination timer. As long as the above-mentioned cyclic calling is repeated and the returned detected smoke concentration data does not fall below the set detected smoke concentration, the count by the internal timer continues, and when the count ends, the returned detected smoke concentration data exceeds the set detected smoke concentration. If it is determined that the detection has exceeded the set time, it is determined that a fire has occurred, and the fire alarm is alerted by the bell 31ktP. By the way, if the intelligence type smoke detector 2 is set as a target for issuing a warning requiring attention, first compare the smoke density lower than the set detected smoke density with the detected smoke density data, and this comparison judgment will indicate whether the detected smoke density is detected or not. If the smoke density data is lower, it is determined that a warning is required and that no alarm is required. On the other hand, if the value is high, a caution warning timer starts counting for a predetermined period of time. The above-mentioned cyclic calling is repeated, and the count of the caution warning timer continues m times until the returned detected smoke concentration data does not become less than the set detected concentration. If the detected smoke concentration data does not reach a level one step lower than the set detected smoke concentration until the count-up time, the arithmetic signal processing circuit section 8 determines that caution is required, and generates a caution required warning as a pre-warning. By the way, if the detected smoke concentration data exceeds the set detected smoke concentration during the count period of the caution alarm timer, the fire judgment timer starts counting and performs the above-mentioned fire occurrence judgment. When the detected smoke concentration data drops below the set detected smoke density while the timer is counting, the count time up to the point of drop is memorized and added.
Reset the fire judgment timer count. If the addition result is less than the predetermined time corresponding to the need for attention,
The process returns to the count routine of the caution warning timer. Further, when the above-described added value of the period during which the detected smoke concentration data exceeds the set detected smoke concentration reaches a predetermined time or more, the arithmetic signal processing circuit section 8 determines that caution is required, and issues a warning that caution is required. Now, when determining the occurrence of a fire as described above, it is determined in the same way whether or not the intelligence type smoke detector 2 is set to issue an AND alarm, and if not, a fire alarm is received. Aircraft 1 issues an alert. In addition, if it is set to issue a logical product alarm, it is determined whether or not other intelligence-type smoke detectors 2 that are set in combination with the intelligence-type smoke detector 2 are also determined to have caused a fire. If the judgment is "YESJ", a fire alarm will be issued from the receiver 1. When a fire occurrence is determined, the interlocking settings will be set in advance for the intelligence type smoke detector 2. The receiver 1 outputs control signals to the smoke prevention equipment, fire extinguishing equipment, etc. that are in operation to activate them, and also displays on the display sections 17 and 17' which sensors and equipment are in operation, and It is preferable to set the above-mentioned caution alarm setting for all intelligence-type smoke detectors 2, but depending on the smoke density,
This does not apply if the time setting is set to low sensitivity. Further, if at least two of the smoke detectors 2 connected to the same signal line 1 issue an alarm, it may be determined that a fire alarm has been issued. In addition, the logical product alarm is issued when all of the combined intelligence type smoke detectors 2 are determined to have detected a fire outbreak. If the installed intelligence type smoke detector 2 determines that a fire has occurred at the beginning or in the middle, it is determined that a fire has occurred at that time.Priority determination 8! Of course, it is also possible to provide a performance function. Further, the logical product alarm may be used for interlocking operation with the smoke prevention device and the fire extinguishing device, and the occurrence of a fire may be alarmed when each smoke sensor 2 determines the occurrence of a fire. FIG. 6 shows a 70-chart of the arithmetic signal processing circuit unit 8 related to the above-mentioned fire occurrence determination and caution warning warning, and FIGS. 7(a) to (d) show the fire occurrence determination and caution warning warning. The relationship between the comparative operation of the determination and the smoke concentration detected by the intelligence smoke detector 2 is shown. Figure 7(a) shows I,■,
The setting level of the detected smoke concentration is shown in three stages (■). In the figure, the detected smoke concentration is set to the level (■) and the detected smoke concentration exceeding the level H continues for more than the set time TI, that is, it is determined that a fire has occurred. Indicates a state in which FIG. 7(b) shows that the time when the set level ■ is exceeded is shorter than the set time TI, and the time when the time exceeds the lower level I for discriminating caution required is shorter than the predetermined time TI [for discriminating caution required. This indicates a short state, that is, a state in which the state is determined to be a temporary state due to a disturbance, etc., and neither a fire alarm nor a warning requiring attention is issued. Figure 7(c) shows a state in which the level ■ continues for a predetermined time T■ or more, that is, a state in which it is determined that it is necessary to issue a caution warning due to either a fire or a setting failure. shows. In addition, Fig. 7(d) shows that the detected smoke concentration intermittently exceeds the set level ■, and the total amount of time it exceeds is 1 at the specified time.
7FJTH is shown, and this state is also shown in Figure 7 (e
) indicates a state in which it is determined that it is necessary to issue a caution warning. Therefore, by issuing the above-mentioned caution warning, it is possible to easily discover incorrect settings, and the setting sensitivity of each smoke detector 2 can be calibrated after the system is installed, thereby optimizing the system without false alarms. It is. By the way, the fire sensitivity level shift shown in chart 70 in FIG. There is. In other words, for example, if the standard sensitivity is a combination in which the setting time is 6 seconds and the detected smoke concentration is 10%, the sensitivity of the intelligent smoke detector 2, which is set to a lower sensitivity than this standard sensitivity, will be one step higher. As such, the arithmetic signal processing circuit section 8 switches either or both of the set time and the set detection smoke density corresponding to the target intelligence type smoke detector 2 for the set fire sensitivity level shift when determining the occurrence of a fire. . Therefore, at the same time as determining the occurrence of a fire, the fire detection sensitivity corresponding to the target intelligence type smoke detector 2 increases,
This makes it possible to quickly detect the state of fire spread. By the way, depending on changes in the environment and management conditions such as daytime and nighttime, when people are present and when there are no people, etc., it may be necessary to change the fire detection sensitivity corresponding to each intelligent smoke detector 2, but in this system, the keyboard The arithmetic signal processing circuit section 8 is provided with a sensitivity level shift function for switching the sensitivity of the intelligent smoke detector 2 selected and set by a command input from 12 or a command automatically added at a preset time. be. In other words, you can switch to low sensitivity during the daytime or during manned periods when malfunctions such as cigarette smoke are likely to occur, or conversely, set it to high sensitivity during the daytime or during manned periods where you can deal with false alarms, and then set it to high sensitivity at night or during unmanned periods. In some cases, the sensitivity is set to low. In this case, the sensitivity changing element may be programmed to switch the set time to the long time side, or to set the set detected smoke concentration one step lower if the set time is set to the long time side. Furthermore, this system includes external gls8! such as a fire extinguishing device that is linked to a prescribed smoke detector 2, and a smoke prevention device. It has an interlocking function that activates the corresponding external equipment when a fire occurrence is determined by the smoke detector 2 that automatically responds. It is provided with an interlocking level setting function 82 that automatically switches the set sensitivity corresponding to the smoke detector 2 to a lower sensitivity side when an instruction is set. Now, as mentioned above, there is a fire outbreak or a warning is required. ! When the alarm is issued by the receiver 8!1, alarm confirmation information is sent from the receiver Miso 1 to the smoke detector 2 as a transmission signal Vs when the dog accesses it, and the smoke detector 2 receives this information. When information is received, the operation signal processing circuit unit 26 lights up the light emitting diode 30 to display the operation. This display makes it easy to determine whether or not the system functions are operating normally during construction, maintenance, etc., and during test operations. Now, the intelligence type smoke detector 2''C which received the alarm confirmation information has 7 circuits and 7 circuits to stop outputting as a general type sensor which is a buffer knob function.
The operation of 8 is controlled. Next, the operation of the intelligent smoke detector 2 will be explained. The smoke detection section 19 of the smoke detector 2 detects that the light emitted from the light emitting section 19a is scattered or blocked by smoke and is received by the light receiving section 19b, and detects the amount of received light, that is, the smoke concentration. An analog signal corresponding to the output voltage is generated via a zero level shift circuit section 20 and an output circuit section 21. The analog signal outputted from this output circuit section 21 is processed by the level discrimination circuit section 24 as described above.
This discriminated data is taken into the arithmetic signal processing circuit section 26, and based on this data, it is sent back to the receiver 8!1 as detected smoke concentration data via the coupling circuit section 27. It will be done. Of course, it is also possible to convert the analog signal (i) to A/D without discrimination and send back the raw data of the detected smoke concentration. If there is a detection corresponding to the sensitivity, this detection period is counted by a built-in timer, and when a predetermined time is exceeded, the signal #Il is short-circuited via a resistor and a level signal similar to that of a general smoke detector is connected to the coupling circuit g27. For example, even if the arithmetic signal processing circuit unit 26 using the CPU causes trouble due to noise or the like, a smoke detection signal can be generated regardless of the operation of the arithmetic signal processing circuit g26. Of course, if the arithmetic signal processing circuit section 26 is normal and is sending back the detected smoke concentration data, the alarm confirmation information from the receiver 1 side can be used as a backup function as described above. The output of the smoke detection signal from the 7th circuit section 28 is stopped.In addition, the 7th circuit section 28 outputs a signal to the level discrimination circuit section 24 for discriminating the level of high smoke concentration detection at the 4th stage. Of course, it is also possible to provide a function and operate when the level discrimination circuit section 24 detects this high smoke concentration.
This is a circuit for correcting the zero level that occurs when 9e becomes dirty or deteriorates. In other words, if the output level of the smoke detection unit 19 when the smoke concentration is zero is zero level, this zero level was initially set at point A as shown in Figure fJ & 8, but due to dirt or deterioration, the mouth or Although it begins to rise or fall step by step like a convex curve, the zero level shift circuit section 20 detects this rise or fall and always shifts the zero level to correspond to the mouth or convex curve. In addition, the self-check circuit WS23 determines that the visit is to be stopped when the zero level shift range of the zero level shift circuit section 20 exceeds the range of x and x' shown in FIG.
A function failure detection signal is output to the function failure determination circuit section 22. The range of the zero level shift is determined by the smoke detection ability of the smoke detection section 19, allowable dirt, and degree of deterioration. Now, the function stoppage determination circuit section 22 switches the output from "L" to "H"' at the same time as the function stoppage detection signal is input, and the smoke detection section 19 outputs 8! Performing that Noh has stopped! :' It is transmitted to the IM signal processing circuit section 26. When called by the receiver 1, the arithmetic signal processing circuit unit 26 returns function stop data to notify the receiver 1 side that the function of the smoke detection unit 19 of the smoke detector 2 has stopped. Display section 17
Or it is displayed as 17'. Therefore, with this display, the administrator can immediately replace the smoke detector 2, thereby preventing false alarms. In this way, in this system, both the receiving M8!1 and 1 smoke detector 2 are made intelligent to divide the functions, and furthermore, the general smoke detectors 3a and 3b are allowed to coexist, increasing the MWi performance of the system. Moreover, by constantly calling the intelligence type smoke detector 2 from the reception Wi1, the detected smoke concentration data from the smoke detector 2 can be monitored (8!
The status of sensor 2 is constantly monitored to ensure reliable system operation. [Effects of the Invention 1] The present invention includes a smoke detector that outputs a detection signal formed by digitally converting analog data corresponding to smoke density, and a smoke detector that is connected to the smoke detector via a signal circuit. Since the receiver is equipped with a fire determination means that determines a fire when it detects that the smoke concentration exceeds the set detection smoke concentration and continues for a set time, the sensitivity is determined only by the smoke concentration as in the past. Compared to other systems, there is less risk of malfunction due to temporary smoke generation or external disturbances, and as a result, there are no false alarms, resulting in high reliability. is gone,
It has the effect of being able to reliably warn of the occurrence of a fire, and furthermore, detects that the detected smoke concentration has exceeded the pre-alarm concentration, which is set lower than the set concentration in the receiver, and has continued for a predetermined time, or has exceeded the set detected smoke concentration. Since the device has a pre-alarm means that issues a caution warning when it detects that the total amount of time spent has exceeded a certain amount of time, it is possible to issue a preliminary warning before the main warning, and as a result, a fire does not actually occur. In the case of a false alarm, it can be used as a reference for sensitivity settings, and each smoke detector can be set to the optimal sensitivity according to the installation status, improving system reliability. play.

[Brief explanation of the drawing]

FIG. 1 is a schematic overall configuration diagram of the present invention, FIG. 2 is a signal waveform diagram used in the above, and FIG. 3 is a circuit block diagram of the same receiver.
Figure 4 is an exploded perspective view of the body of the intelligence type smoke detector of the same type, Figure 5 is a circuit block diagram of the intelligence type smoke detector of the same type, and Figure 6 is a block diagram of the intelligence type smoke detector of the same type.
0-chart, FIGS. 7(a) to 7(d) are diagrams explaining the operation of the same as above, and FIGS. Intelligence type smoke detector, 3a is a general type smoke detector, 3b is a general type heat sensor, 8.16 is an arithmetic signal processing circuit section, 10.14 is a storage section, 12.15 is a keyboard, ! 31 is a signal line, 31 is a bell, Vs is a transmission signal, and ■ is a level signal.

Claims (4)

[Claims] (1) A smoke detector that outputs a detection signal corresponding to the smoke concentration, and is connected to the smoke detector via a signal line, and detects when the smoke concentration detected by the smoke detector exceeds the set concentration and continues for a set time. fire determination means that determines a fire when detected; and detects that the detected smoke concentration exceeds a pre-alarm concentration that is set lower than the set concentration and continues for a predetermined time;
1. A fire alarm system comprising: a receiver having a pre-alarm means for issuing a caution warning when it is detected that the total amount of time exceeding the set detection concentration exceeds a certain period of time. (2) The invention is characterized in that when at least two smoke detectors out of a plurality of smoke detectors connected to the same signal line issue a warning requiring attention, it is determined that a fire has occurred. The fire alarm system described in Section 1. (3) The receiver is provided with selection and setting means for individually selecting and setting the detected smoke concentration set in the plurality of stages and the set time set in the plurality of stages, respectively. Fire alarm system as described in paragraph or paragraph 3. (4) Connect a general type sensor to the signal line that, when it detects smoke or heat at a predetermined concentration, changes the signal line voltage level, current level, etc. to a predetermined level and transmits the detection output as a level signal to the receiver side. A patent characterized in that a smoke sensor that generates a detection signal corresponding to smoke concentration transmits detection data based on the detection signal to a receiver by a transmission signal superimposed on the signal line. A fire alarm system according to claim 1, 2, or 3.