JPH01194098A - Fire alarm system - Google Patents

Abstract

PURPOSE:To stably detect a fire even when the rise of a sensor output level is in any state at the time of generating a fire by outputting 1st and 2nd fire signals when an integrated value reaches the 1st and 2nd prescribed integrated values. CONSTITUTION:1st and 2nd integrating means respectively integrate the sensor output level respectively exceeding the 1st and 2nd prescribed levels LV1, LV2 and a deciding means decides that the a value SI1 integrated by the 1st integrating means reaches the 1st prescribed integrated value A, outputs the 1st fire signal, and at the time of deciding that a value SI2 integrated by the 2nd integrating means reaches the 2nd prescribed integrated value B, outputs the 2nd fire signal. In case of a fire having a sudden rise, the operation level of the sensor is increased, and in case of a fire having a moderate rise, the fire is detected at a low level. A quick fire or a slow fire can be decided by the generating state of the 1st or 2nd fire signal.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fire alarm system, and in particular, the present invention relates to a fire alarm system that detects a fire by a fire detector itself or by data sent from a fire sensor to a receiver via a transmission line. This relates to a fire alarm system that determines the

[Prior art and its problems] Photoelectric smoke sensors, thermal sensors using thermistors, and ionization or radiation sensors are known as detectors or sensors for detecting fire. Each of these fire detectors detects a predetermined smoke density, a predetermined temperature, or a predetermined radiant light caused by a fire, and issues a fire signal.

However, in such a system, even transient smoke such as cigarette smoke may cause the detection level to exceed the predetermined detection level.

Therefore, in order to prevent activation due to such a temporary fire phenomenon, there are also known accumulation-type sensors or receivers that use a timer or the like so that they do not operate unless a predetermined output is continuously generated for a certain period of time. However, it had the disadvantage that fire detection was delayed.

Furthermore, in a room where a ventilation system is working, its action causes, for example, a gradual increase in the concentration of smoke, and in the end it does not reach the smoke concentration that activates the smoke detector, resulting in no fire alarm, i.e. a false alarm. There were cases like this.

As a solution to such problems, for example, the specification attached to Japanese Patent Application No. 153491, entitled "Fire Alarm System J," filed by the applicant on June 22, 1986, states: When the sensor output level sampled at each predetermined time interval is equal to or higher than a first predetermined level, the difference between the sensor output level and the first predetermined level is accumulated at each predetermined time interval. , has been disclosed that determines when the integrated value does not reach a predetermined integrated value and outputs a signal indicating an abnormality.In the content of this earlier application, if a fire actually occurs, However, it is not possible to distinguish between fast-growing fires and slow-growing fires, and it is highly desirable to be able to determine the speed at which such fires develop in order to provide a more reliable fire alarm system that does not malfunction.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and it does not malfunction due to transient fire-like phenomena such as cigarette smoke, and has a slow rise. Even if it is an actual fire, it can be detected reliably and early and an alarm can be issued, and furthermore, if a fire actually occurs, it can be determined whether it is a fast-growing fire or a slow-growing fire. The purpose of this invention is to provide a fire alarm system that enables the following.

Therefore, according to the present invention, in a fire alarm device that determines a fire based on a sensor output level (SLV), the sensor output level is equal to or higher than a first predetermined level (LVI), and the first predetermined level The difference between
The first integration means (step 1) that integrates for each
10), and a second predetermined level (L
V2) a second integration means (step 112) that integrates the difference between the above sensor output level and the second predetermined level at each predetermined time interval; The value integrated by the integration means (S
+, and 5I2) with the first and second predetermined integrated values (A and B), respectively, steps 113 and 121;
and Step 119), determining when the value integrated by the first integrating means reaches the first predetermined fljE value and outputting a first fire signal (Step 114)
and 122, and Y in step 126), it is determined when the value integrated by the second integrating means reaches the second predetermined integrated value, and a second fire signal is output (step 120). , and Y) determination means in step 127, and a fire alarm device is provided.

[Operation] In this way, the first and second integrating means adjust the sensor output level to the first and second predetermined levels LV+ and L, respectively.
The portion equal to or greater than V2 is integrated with respect to time, and the determining means determines that the value S+, integrated by the first integrating means, is the first
determines when a predetermined integrated value A has been reached and outputs a first fire signal, and when the value SI2 integrated by the second integrating means has reached the second predetermined integrated value B; Therefore, in order to notify the occurrence of a fire, the integrated value for the portion of time equal to or higher than the first predetermined level must reach the first predetermined integrated value A. or the integrated value for the portion of time equal to or higher than the second predetermined level must reach the second predetermined integrated value B. As a result, the operating level of the sensor is set high for a fire that starts rapidly, and the fire is detected at a low level for a fire that starts slowly, and the first fire signal or second fire signal Depending on the manner in which the fire occurs, it can be determined whether the fire is early or late.In this way, stable fire detection is possible no matter how the sensor output level rises when a fire occurs.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
Figure A shows the output level of the fire sensor with respect to time, and in Figure 1A, the horizontal axis shows time t, and the vertical axis shows the output level SLY of the fire sensor. LV+
is a first predetermined level, LV is a second predetermined level, and LV is a third predetermined level. Now, if we proceed with the explanation assuming that the sensor output level SLV rises along the straight line S, the sensor output level SLY will first rise at time 1.
, exceeds the first predetermined level Ll/, and from this point on, the sensor output level SLY exceeds the first predetermined level LV,
Start accumulating the excess amount over time. Specifically, this integration is obtained by subtracting the first predetermined level LV+ from the sensor output level SLV (SLY-tv,)
, for each time interval Δt, that is,
This is done by calculating the following equation (1).

Here, 5LVk is the time t1, t for each time interval Δt.
Sensor output level SL at z, tn-..., tn
This is the value of V.

Also, the senna output level SLV is at the second level at time tm.
When the sensor output level SLV exceeds the second predetermined level LV2, from this point on, the excess of the sensor output level SLV with respect to the second predetermined level LV starts to be integrated over time according to the following equation (2).

outputting a first fire signal when the first integrated value S+ expressed by equation (1) reaches a first predetermined integrated value A;
Further, when the second integrated value S[2 expressed by equation (2) reaches the second predetermined integrated value B (B<A), a second fire signal is output. A difference appears in the times at which the first and second integrated values SI and S12 reach the first and second predetermined integrated values A and B, respectively, depending on the rising slope of , and by identifying this difference, It is possible to detect slow or fast fires.

That is, first the constants A and B are selected such that S1<A and S12<B for transient smoke.

For a fire that starts suddenly, there is a high possibility that Sl will exceed B before Sit exceeds A, and in this case, the fire will be classified as fire 2. When the first predetermined level LV exceeds 4, "abnormal" is displayed, so when the transition from abnormality to fire 2 occurs, it can be seen that the fire is rapidly expanding.

Next, in a fire that grows slowly, S11 exceeds A,
After that, SLY becomes the second predetermined level LV.

Since there is a high possibility that S12≧B will be satisfied, the transition will be from normal to abnormal to fire 1 to fire 2.

Furthermore, in the case of a fire occurring in a ventilated room, the sensor output level SLY may not exceed the second predetermined level LV2 and remain in the fire 1 state at Sl, ≧A. In such cases, only one conventional predetermined level, e.g.
If the operating level is only a value near the predetermined level LV2 of This means that the sex is being reduced.

To summarize the above, i) When normal SLV < LV+, ii) When abnormal SLV≧Lv1 and Sr<A S12<B, iii) When there is a slow fire (fire 1) SLV ≧ When LV, Te, KatsuSI+≧AS12<B, iv) Fire that occurs quickly2) When SLY>LV2F, KaSlz≧,B, then the third in item iii) above The role of the predetermined level LV, is as follows:
In the explanation of FIG. 1A, an example was explained in which the sensor output SLV rises along the straight line S when an abnormality occurs.
In reality, it does not necessarily rise along a straight line, and furthermore, the integrated value S1. When SLV reaches the first predetermined integrated value A, for example, the abnormal condition has been resolved and the sensor output SLV
may be gradually decreasing, for this reason reaching the first predetermined integrated value A and the third predetermined level LV.

Only when both of the above conditions are satisfied, it is determined that there is a fire 1 and the first fire signal is output.

In FIG. 1B, the sensor output level SLV is
1, S2, S, . . . The first integrated value 'Sl, is the first predetermined integrated value A.
The locus of the points on the graph at the time when S1. The locus of the points on the graph at the time when B reaches the second predetermined integrated value B is shown by a line L2.

As shown in FIG. 1B, if the smoke concentration increases along a higher rate of increase than the rate of increase of the straight line S2, that is, along a straight line to the left of the straight line S (for example, the straight line S), the S
Since SI2 reaches B before l, reaches A, it is determined that it is fire 2, and if the rate of increase is lower than that of straight line S2, for example, straight lines S0, S
, ), Sl, reach A first, so it is determined that there is a fire 1.

Note that since the line L1 shown in FIG. 1B is the operating point of the sensor, the first and third predetermined levels LM.

and LV are set to values sufficiently lower than the levels in conventional sensors, that is, to high sensitivity. Taking the case of a smoke sensor as an example, conventionally the smoke concentration is 10%/I11
For example, if it is set to operate at the first predetermined level LV.

2.5 to 3%/turn and a third predetermined level LV,
It is set to 5%/+11.

FIG. 2 shows a block circuit diagram of a fire alarm system suitable for carrying out the present invention, which is operationally explained in FIGS. 1A and 1B. 10 and a determining section 11. Sensor part 1
Here, 0 is a photoelectric smoke sensor that operates by sensing smoke.

The smoke detection chamber of the smoke sensor unit 10 includes a light emitting diode LED that is pulse-lit at a predetermined period by an oscillation circuit 12 and a light emitting circuit 14, and receives scattered light proportional to the concentration of smoke when it flows into the smoke detection chamber. A solar cell SB is provided, and the output from the solar cell SB is amplified by an amplifier 18 via a light receiving circuit 16, and then analog/digital (A/
D) It is converted into a digital signal by the conversion circuit 20 and sent to the discrimination section 11.

The determination unit 11 that receives the signal from the sensor unit 10 and performs signal processing or discrimination includes a microprocessor unit MPU, an interface IF that receives the signal from the sensor unit 10, and an oscillation unit O8C that oscillates a clock.
A program read-only memory ROM1 that stores signal processing programs and a random memory for working.
an access memory RAM1, a level storage read-only memory ROM2 storing first, second and third predetermined levels LV, LV, and LV; 0.1.
a constant storage read-only memory ROM3 storing constants 2 and 3; and a first and second predetermined integrated value A.
and B, a read-only memory ROM4 for storing predetermined integrated values, and a random access memory RAM2 for storing sensor outputs for capturing and storing the sensor output level SLY at predetermined time intervals Δt. , R.A.
The integrated value S1.M2 is calculated at predetermined time intervals Δt based on the sensor output level SLV taken into M2. and a random access memory RAM3 for storing integrated values for storing SI2 and SI2, and a constant 0.1.2 or 3 stored in ROM3 to indicate which range the value of the sensor output level SLY is currently in. The variable X expressed by
and integrated value St.

or a variable storage RAM 4 for storing a variable Y representing the current state of the value of S12 by one of constants O11, 2, or 3 stored in the same <: ROM3, and an interface IF2. It includes an abnormality indicator light ABL, a first fire indicator light FFL, and a second fire indicator light SFL, which are connected through the fire indicator light.

Note that the first predetermined level LV, the second predetermined level LV
2. Third predetermined level LV3, first predetermined integrated value A,
And the value of the second predetermined integrated value B is based on the danger level of the room, ventilation,
Those skilled in the art will understand that settings can be changed as appropriate depending on air conditioning, density of people, time of day, height, volume, etc.

The operation of the block circuit diagram shown in FIG. 2 will be explained using the flowcharts of FIGS. 3A and 3B.

First, the determination section including the microprocessor unit MPU constantly samples the sensor output level SLY based on a program stored in the ROM1. That is, the sensor output level SLY sent from the sensor unit 10 via the interface IF is read into the RAM 2 at every predetermined time interval Δt counted based on the clock pulse from the oscillation unit O8C ( In step 101), the sensor output level meter () read into the RAM2 is the first and second level meter stored in the ROM2.
is compared with predetermined levels LV and LV2, and it is determined in which range the sensor output level SLY falls (steps 102 to 106).

That is, if the sensor output level SLY is smaller than the first predetermined level LV (N in step 102), the constant O stored in the ROM3 as the variable X is set in the RAM4 (step 103), and the sensor output level SLY is First predetermined level LV.

If the above is the case (Y in step 102) and it is smaller than the second predetermined level LV2 (N in step 105), set constant 1 as variable X in RAM4.Step 104
), and if the sensor output level SLV is equal to or higher than the second predetermined level LV2 (Y in step 105), a constant 2 is set as the variable X (step 106).

If x; 0, that is, the sensor output level SLV
is smaller than the first predetermined level LV (N in step 107 and Y in step 108), both the first and second integrated values SI+ and SL are cleared, and the variable Y, which will be described later The value of is set to 0 (step 109).

If X=1 or 2, that is, if the sensor output level SLV is at least the first predetermined level LV or higher (Y in step 107), then the first predetermined level LM is calculated from the current sensor output level SLV. The subtracted value is
The first integrated value Sl stored in RAM3 up to the previous time
, is added to the first integrated value S1. stored in the RAM 3. (step 110);
Furthermore, if X=2, that is, if the sensor output level SLY is also higher than the second predetermined level L12 (Y in step 111), the current sensor output level SLY is changed to the second predetermined level. The second integrated value SI stored in the RAM 3 is obtained by adding the value obtained by subtracting LV2 to the second integrated value SI2 stored in the RAM 3 up to the previous time.

(step 112), if X=2, that is, if the sensor output level SLY is greater than or equal to the first predetermined level LV and smaller than the second predetermined level LV (step 111, N , and Y in step 115), the second integrated value S12 stored in the RAM 3 is cleared (step 116).

Next, state determination will be explained.

To the hole side 41 X = 1 and Sl, < A of the cover step 117 Y)
, :i TAHAX=2 TEATTE also SI2<B KASI+KUA (Y at step 123), it is determined that there is an abnormality and Y in the RAM 4 is set to Y=1 (step 118 or 124>).

41 If X=1, SI, ≧A or SLV≧L■ (Y in step 113), or if X=2, S12<B and S
If l, ≧A (Y in step 121), Y in the RAM 4 is set to Y=2 as fire 1 (step 114 or 122).

If 1x=2 and S12≧B (Y in step 119)
, Y in the RAM 4 is set to Y=3 as fire 2 (step 120>).

The status is displayed using the value of Y set in this way. That is, if Y=O (that is, if the determinations in steps 125, 126 and 127 are N), a normal display is performed (step 128), and if Y=1 (Y in step 125), for example, as shown in FIG. An abnormality display is performed by lighting up the abnormality indicator light ABL (step 129), and if Y=2 (N of step 125 and step 12
6 Y), a fire 1 indication is performed by, for example, lighting the first fire indicator light FFL in FIG. 2 (step 130).
, and if Y=3 (N in steps 125 and 126, and 1
27 Y), the fire 2 display is performed by, for example, lighting the second fire indicator light SFL in FIG. 2 (step 13).
1).

When any of these displays is performed, the process returns to step 101, a new sensor output level SLV is set at the next sampling period, and the same determination from step 102 is performed, and a new display is made as a result of the determination. Therefore, as the sensor output level SLV changes with the progress of the fire, the displayed content will also change, and by monitoring the changes in the displayed content, the observer or operator can prevent a slow fire as described above. Alternatively, it is possible to judge early fire.

Note that the judgment results may be displayed separately, that is, only the current status may be displayed sequentially, or a CRT or the like may be used to make it possible to see the order of display, leaving the previous displayed content without erasing it. Further, it is also possible to automatically determine whether a "late fire" or "early fire" is detected based on the order in which the first fire signal or the second fire signal occurs. The indicator light or CR
It is also possible to use T or the like.

In the above embodiments, the sensor output level was explained as a signal obtained from a photoelectric smoke sensor, but the sensor output level is a signal obtained from a thermal, ionization, or radiation fire sensor using a thermistor. Even in this case, the same effect as in the above embodiment can be achieved.

In addition, in the above embodiment, the sensor section and the fire discrimination section of the fire alarm system are assumed to be integrated.
The fire sensor output digitized by the D conversion circuit may be transmitted to a remote receiver via a modem or the like, and the fire determination may be made there.

Furthermore, in the above embodiment, the sensor output level SLY
are the first and second predetermined levels I, (1) and LV.

In the above cases, the first and second integrated values Sl.

and until SI2 reaches the predetermined 8I calculation values A and B,
A limit is set on the number of integrations per predetermined time interval ΔL (for example, N times), and if Sl and Sl do not reach A and B within the limited number of integrations, the limited fi When the number of calculations is reached, Sl and/or Sl
The value of z may be cleared and the integration operations in steps 110 and 112 may be performed from the beginning. In this way, the fire-like phenomenon has already been resolved and only the smoke remains, and the first Alternatively, in a case where it takes a considerable amount of time to output the second fire signal, it is possible to prevent unnecessary notification of the occurrence of a fire. In addition, in this case, if the limit on the number of integrations until Sl, reaches B is set smaller than the limit on the number of integrations until Sl, reaches A, malfunctions due to transient phenomena that rise quickly can be avoided. It is believed that this method can be expected to be even more effective in preventing this.

[Effects of the Invention] As described above, according to the present invention, the part of the sensor output level that is above the first predetermined level is integrated as the first integrated value, and the part that is above the second predetermined level is integrated as the second integrated value. When these integrated values reach the first and second predetermined integrated values, the first and second fire signals are output, respectively, so that cigarette smoke, etc. It does not malfunction in the event of a transient, fire-like phenomenon, and even if it is a slow-starting fire, it can reliably and early detect an actual fire and issue an alarm. When a fire actually occurs, it is possible to determine whether it is a fast-developing fire or a slow-developing fire.In this way, no matter how the sensor output level rises when a fire occurs, the fire can be detected stably. This has the effect of being able to detect.

[Brief explanation of the drawing]

1A and 1B are graphs for explaining the present invention in detail, FIG. 2 is a configuration diagram showing a fire alarm system according to an embodiment of the present invention, and FIGS. 3A and 3B are graphs for explaining the present invention in detail. 2
It is a flowchart for explaining the operation of the figure. In the figure, 10 is a smoke sensor section, 11 is a discrimination section, and MPU
is a microprocessor unit, ROM1 is a read-only memory for program storage, ROM2 is a first predetermined level LV, a second predetermined level LV2, and a third predetermined level LV.
ROM3 is a read-only memory for storing constants, ROM4 is a read-only memory for storing a predetermined level LV, and ROM4 is a first predetermined integration value, value A, and a second predetermined integration value. RAM1 is a working random access memory, RAM2 is a random access memory for sensor output storage, and RAM3 is a random access memory for storing a sensor output level SLV. is the first WIyL value S+,
and a random access memory for storing the second cumulative value SI2, and RAM4 is a random access memory for storing the second cumulative value SI2.
This is a random access memory for storing variables. Figure 1A Crane IB diagram

Claims (1)

[Claims] In a fire alarm device that determines a fire based on a sensor output level, the difference between the sensor output level that is equal to or higher than a first predetermined level and the first predetermined level is determined by a predetermined value. a first integrating means that integrates at each time interval, and calculates the difference between the second predetermined level and the sensor output level that is higher than the second predetermined level that is larger than the first predetermined level; a second integrating means that integrates at each time interval, and a value integrated by the first and second integrating means,
Compare each with a first and second predetermined integrated value, determine when the value integrated by the first integrating means reaches the first predetermined integrated value, and output a first fire signal. and determining means for determining when the value integrated by the second integrating means reaches the second predetermined integrated value and outputting a second fire signal. fire alarm system.