JPH01276294A - Fire alarm - Google Patents

Abstract

PURPOSE:To early discover a fire in the stage of the smoke fire by stopping an air conditioner operation for a first prescribed time when the arrival of a sensor output level at the first prescribed level is discriminated with a sensor output level discriminating means. CONSTITUTION:When the fact that the sensor output level of a fire phenomenon outputted by a fire phenomenon detecting means exceeds a first prescribed level (for example, approximately a half of the fire discrimination reference level) LV1 is discriminated by the sensor output level discriminating means, an air conditioner stopping means stops the air conditioner operation provided at such a place or a zone for the first prescribed time, and monitors the transition or tendency of the change of the sensor output level of the fire phenomenon in the condition of air conditioner operation stopping. By stopping the air conditioner, at the time of the actual fire, the sensor output level sharply rises, thereafter, when the sensor output level arrives at a fire discrimination reference (for example, a second prescribed level or a first prescribed rising rate), it is judged as the fire (the main fire or a per-alarm). Thus, the fire can be early discovered.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fire alarm system that determines a fire abnormality based on physical quantities such as heat, smoke, or gas, and particularly relates to a fire alarm system that determines a fire abnormality based on physical quantities such as heat, smoke, or gas. This invention relates to a fire alarm system aimed at early detection of fire abnormalities.

However, the conventional technology and problems: Even if the amount of heat, smoke, gas, etc. detected by the fire phenomenon detection means is the same, the detection of the fire phenomenon may be affected by the influence of the air conditioning equipment in operation. The detection outputs detected by the means are different, and therefore false alarms or 1
This may result in news or misinformation.

In recent years, air conditioning equipment has been installed in most office buildings, and a variety of air conditioning methods have been introduced, including ceiling airflow, ceiling suction, anemo airflow, and wall return. In smoldering fires with low heat energy, smoke may not reach the ceiling;
With air conditioning systems that blow out from the ceiling or suck in air from the ceiling, smoke enters the inlet and rarely flows along the ceiling surface. This makes it difficult for fire detectors to detect fires.

As described above, when air conditioning equipment is operated, there is a drawback that the fire is not detected until it spreads and the smoke is uniformly spread throughout the room, making it difficult to detect the fire early in the smoldering stage.

[Means for Solving the Problems] Therefore, according to the present invention, there is provided a fire phenomenon detection means that detects a physical quantity based on a fire phenomenon and outputs a sensor output level;
and a fire alarm device equipped with a fire discrimination means that determines that there is a fire when the sensor output level from the fire phenomenon detection means reaches a fire discrimination standard, wherein the sensor output level is detected in an air-conditioned environment. a sensor output level determining means for determining whether or not the sensor output level has reached the first predetermined level; and when the sensor output level determining means determines that the sensor output level has reached the first predetermined level; There is provided a fire alarm device comprising: an air conditioning stop means for stopping the air conditioning operation for a first predetermined period of time.

According to another aspect of the present invention, the air conditioning stop means is configured to reduce the sensor output level to If the fire discrimination means does not determine that the fire discrimination standard has been reached, the air conditioning operation is switched to the second mode.
This is also done over a predetermined period of time.

[Function] The sensor output level of a fire phenomenon output by the fire phenomenon detection means in an environment where air conditioning is being operated is at a first predetermined level (for example, a level of about 172 of the fire discrimination standard level).
When the sensor output level determination means determines that the sensor output level has exceeded the limit, the air conditioning stop means stops the air conditioning operation installed in that place or area for a first predetermined period of time, and prevents the fire while the air conditioning operation is stopped. The transition or trend of change in the sensor output level of the phenomenon is monitored.

In the case of an actual fire, the sensor output level rises rapidly due to the air conditioning being stopped, and then, when the sensor output level reaches the fire discrimination standard (for example, the second predetermined level or the first predetermined rate of increase), the sensor output level rises rapidly. It is determined that there is a fire (main fire or preliminary warning).9 This makes it possible to detect fires early.

After the air conditioning is stopped, in the case of a temporary phenomenon, the sensor output level will not change, or if it changes, it will change only slightly, so it will not exceed the fire discrimination standard during the first predetermined time. According to another aspect of the invention, the air conditioning stop means causes the air conditioning operation to be performed again for a second predetermined time period after the first predetermined time period has elapsed. As a result, in the case of a temporary phenomenon, the indoor environment quickly returns to a normal state, and false alarms are prevented.

[Example] Examples of the present invention will be described below, but first, the effect of the present invention will be explained using smoke detection as an example.
This will be explained using Figure A and Figure 1B. Figure 1A and 1
In Figure B, the upper row shows the change in the sensor output level StV (vertical axis) from the fire phenomenon detection means with respect to time t, and the lower row shows the change in whether the air conditioner is turned on or off with respect to time t (horizontal axis). R (vertical axis) is shown.

Conventionally, when performing fire detection under air conditioning, it has been difficult to detect the initial state of a fire. In the present invention, in order to reliably detect an initial fire, the sensor output level SLV increases as shown in FIG. 1A until time 1. 1st in
The predetermined level LV.

When this happens, the air conditioning operation is first turned off or stopped in order to determine whether there is a fire or not. In the case of a fire, the sensor output level continues to rise even though the air conditioning operation is stopped, and during the first predetermined time M, the rate of increase in the sensor output level SLV reaches the first predetermined rate or slope of INCR, or more. If the sensor output level SLV reaches the second predetermined level LV2, an alarm or fire alarm is output (time tz).

The first predetermined level L1 is set to a low value of, for example, 2.5%/lol, and the second predetermined level LV2 is set to a high value of, for example, 10%. If the air conditioning is stopped when the sensor output level SLV exceeds the first predetermined level LV+ during air conditioning operation, the smoke concentration will be does not change, or even if it does change, it increases only slightly and never reaches the second predetermined level L2.

However, in the event of a fire, the smoke concentration continues to rise even after the air conditioning is stopped, and this rate of increase is the first predetermined rate of increase INCR+
In the above cases, if you output a flash alarm,
It is possible to quickly respond to a fire and take various fire prevention or extinguishing measures.

Fig. 1A shows a case where a fire actually occurs and the sensor output level SLY continues to rise to the second predetermined level LV, but Fig. 1B shows a temporary fire phenomenon and the sensor output level SLY continues to rise to the second predetermined level LV. This shows the operation when SLY decreases from the middle.

At time t, after the sensor output level SLV reaches or exceeds the first predetermined level LV, it does not reach the second predetermined level LV2 for the first predetermined time M, and the rate of increase does not reach the first predetermined level LV. At time 1 when the predetermined rate of increase INCR, has not been reached and the first predetermined time M has elapsed.
．． , the rate of increase is a first predetermined rate of increase INCR,
If the rate of increase is smaller than the second predetermined increase rate lNCR2, then the second predetermined time N from that point on,
Operate air conditioning equipment. Due to the operation of this air conditioning equipment, if the fire phenomenon is a temporary one, the smoke that has accumulated in the room is exhausted and the sensor output level SLV falls below the first predetermined level LV. Returns to normal monitoring status. If the sensor output level SLV does not fall below the first predetermined level LV during the second predetermined time N, then at the time t when the second predetermined time N has elapsed,
Then, the operation of the air conditioning equipment is stopped again for the first predetermined time M, and the sensor output level SLV is tracked and monitored.
Time L before expiration of ? Sensor output level SL at
Since V is shown to be below the first predetermined level LV+, at this point the air conditioning equipment will be restarted and returned to normal monitoring status.

In this way, when smoke at a low concentration, that is, the first predetermined level LV, is detected during air conditioning operation, the air conditioning operation is temporarily stopped and the trend of the sensor output level SLY is observed, and if the smoke concentration increases, Since it is determined that there is a fire, it is possible to reliably detect a fire at an early stage.

Hereinafter, one embodiment of the present invention will be described using smoke detection as an example. FIG. 2 shows an example of a fire alarm system to which the present invention is applied. In the figure, RE is a receiver, DE is
~DEnn is a plurality of fire detectors connected to the receiving fiRE, L1 to Ln are the receiver RE and each fire detector DE,
~DEnn, for example, a pair of power and signal lines, AC.

~ACn is air conditioning equipment, and in Fig. 2,
Fire detector DE1. Although the internal circuit is shown in detail only for the fire detector, other fire detectors have similar internal circuits.

At the fire detector DE, MPU is a microprocessor, ROM1 is the program storage area, ROM2 has first and second predetermined levels LV.

and LV, a storage area for various constants of the first and second predetermined rate of increase or slope INCR, and INCR, and the first and second predetermined times M and N, RAM1 stores detection data, that is, sensor output level SLV , RAM2 is a work area, and FS is a fire phenomenon detection means, which in this embodiment is a scattered light type detection section.

TX is a fire signal and/or address signal sending unit; IFI is an interface for fire phenomenon detection means FS, IF5 is an interface for the signal sending unit, and IF3 is an interface for controlling air conditioning equipment.

In the fire phenomenon detection means FS, LED is a light emitting element such as a light emitting diode, LD is a light emission control circuit that causes the light emitting element such as a light emitting diode to emit light every 2 seconds, SB is a light receiving element such as a solar cell, and RC is A sampling system that holds the amplifier and the light receiving amplification output of the amplifier in synchronization with the operation of the light emission control circuit LD.
A light receiving circuit consisting of a hold circuit and the like, AD is an analog-to-digital conversion circuit that converts the analog light receiving output from the light receiving circuit RC into a digital physical quantity signal.

The operation shown in FIG. 2 will be explained with reference to the flowchart shown in FIG.

First, through initial settings, clear the contents of RAM1 and the contents of variables P, Q, and R, which will be described later (Step 101),
And I want to send an air conditioning ON command to the interface IF2. Step 102) 7! , the microprocessor MPU side starts reading the sensor output level from the fire phenomenon detection means FS for each sampling (step 103).
, normal fire monitoring status is established.

Fire phenomenon detection means FS to read sensor output level
In this case, the light emission control circuit LD is driven at a predetermined sampling interval, for example, every two seconds, to cause the light emitting element LED to emit light. When the scattered light emitted from the light emitting element LED and scattered by smoke is received by the solar cell SB, the solar cell SB generates an electric signal corresponding to the received light and provides it to the light receiving circuit RC, The electric signal passes through an amplifier in the light receiving circuit RC and is held at predetermined time intervals in a sampling and holding circuit also in the light receiving circuit RC. The signal held in the sampling/holding circuit in the light receiving circuit RC is converted into a digital analog quantity signal by the analog/digital conversion circuit AD, and the signal is sent to the fire phenomenon detection means F.
The detection output level at S, ie, the sensor output level, is output to the interface IFI.

In this way, when the sensor output level is read from the fire phenomenon detection means FS to the microprocessor MPU at predetermined sampling intervals via the interface IFI, this read sensor output level is stored in the work area RAM2 as SLV. (Step 103), and then the just-read sensor output level SLY is compared with a first predetermined level LV+ stored in the storage area ROM2 for various constants (Step 104).

If the smoke concentration in the environment increases for some reason and the sensor output level SLV starts to rise and reaches the first predetermined level LV+ (Y in step 104), then the second
Since the variable Q for counting the predetermined time N is not greater than 0 at this point (N in step 105), the first
Increment the variable P by one for counting the predetermined time M of 106) and send a command to the interface IF2 to turn off the air conditioning step 107), and all the just-read sensors in the working area RAM2. It is determined whether the output level SLV is equal to or higher than a second predetermined level L12 stored in the various constant storage area ROM2 (step 109).

If the sensor output level SLY is equal to or higher than the second predetermined level LV2 (Y in step 109), the interface IP
2 and an alarm signal is sent to the receiver RE via the signal sending unit TX (step 114), but the smoke concentration in the environment must still increase to the extent that it reaches the second predetermined level LV2. For example (N in step 109), the sensor output level SLY in the work area RAM2 is stored in the sensor output level storage area RAM1 (step 110).
.

The sensor output level storage area RAM1 stores a predetermined number of sensor output levels that are read for each sampling in order to calculate the rate of increase, that is, the slope, of the sensor output level, an example of which is shown in FIG. is shown.

In FIG. 4, the newest sensor output level read at the - most recent sampling period is stored at the top address location of RAM1, and the sensor output levels stored up to that point are sequentially stored one by one. The sensor output levels that are shifted downward and are the lowest or lowest are discarded. In this way, a predetermined number of latest sensor output levels are always stored.

When the latest sensor output level SLV is stored in RAM1, next, the increase rate is calculated based on the sensor output level from the past stored in the R, A M l, and this is used as R for work. Store in area RAM2 (step 1
11) This rate of increase is, for example, the value obtained by subtracting the oldest sensor output level from the latest sensor output level.
It can be divided by the number of sampling times P after the sensor output level reaches a first predetermined level LV.

When the increase rate R is stored in the work area RAM2 in this way, the increase rate R is then stored in the storage area ROM2 for various constants.
(step 112), and if the increase rate R is greater than or equal to the first predetermined increase rate rNcR, stored in the first predetermined increase rate INCR (step 112), then
), and sends out an alarm signal to the receiving fiRE via the interface IP2 and the signal sending unit TX (step 113).

After waiting for a time (step 122), the next sensor output level is read in step 103 at the next sampling period and the same processing from step 104 is continued, thereby determining the subsequent trend of the sensor output level SLV. , and monitors whether it becomes smaller than the first predetermined level LV or exceeds the second predetermined level LV.

If the rate of increase R is a first predetermined rate of increase INCR.

If the count value P is smaller than the predetermined count value M for the first predetermined time period (N in step 112), then the count value P is smaller than the predetermined count value M for the first predetermined time period.
If P has not reached M (N in step 115), after waiting for a time (step 122), in step 103, the next sensor output level is set at the next sampling period. , and similarly determines whether the sensor output level is below the first predetermined level LV, or above the second predetermined level Lv2, or when the rate of increase R is above the first predetermined rate of increase INCR. We will monitor what happens.

When the count value P reaches the first predetermined time M (Y) in step 115, the rate of increase R is stored in the various constant storage areas RO.
the first predetermined increase rate INCR, stored in M2;
Compare with a smaller second predetermined rate of increase lNCR2 (
step 116), if the sensor output level is not less than a second predetermined rate of increase rNcR2 (step 116);
Similarly, in step 103, the next sensor output level is read and the trend of the sensor output level is monitored, but if the rate of increase R becomes smaller than the second predetermined rate of increase rNcR2 ( step 116 N), sends an operation command to the air conditioner via the interface IF3, step 117>, and sets the variable Q to N in order to operate the air conditioner for a second predetermined time N; and clear the contents of RAM1 (step 11
8).

When the value of Q is set to N in this way, if it is determined that the sensor output level SLV is still equal to or higher than the first predetermined level Lv1, then step 104 (Y);
Since it is determined in step 105 that Q is greater than O (Y in step 105), Q is decremented one by one in step 108 until it is determined that Q=O (N in step 105). , air conditioning equipment will not be shut down.

If the smoke in the environment is quickly removed by the operation of the air conditioning equipment, and it is determined in step 104 that the sensor output level read at the subsequent sampling period has become smaller than the first predetermined level LV, the interface IF3 Step 119: Send a turn-on command to the air conditioner.
), P, R, Q, and RAM1 Step 1
20), and a step 121) of sending an alarm and an alarm off signal to the interface IP2.
, return to normal monitoring state.

If the sensor output level read in the subsequent sub-ring period is not determined to be smaller than the first predetermined level LV due to the operation of the air conditioning equipment (step 104
(Y in step 105), and if it is determined that Q=O and the second predetermined time N has elapsed (N in step 105),
The air conditioner is operated again via the interface IF3 (step 107), and the trend of the sensor output level continues to be monitored.

In the above embodiment, the sensor output level is determined on the detector side, and only the results of the fire abnormality or early warning are sent to the receiver R.
We have explained the case in which the present invention is applied to a so-called fire alarm device that sends out signals to the fire alarm, but from the sensor side, the analog fire detector (fire sensor) sends only analog signals to the receiver and detects a fire abnormality. It is also possible to apply the present invention to a so-called analog fire alarm device in which the receiver RE or repeater makes a judgment as to whether or not a fire is occurring based on an analog quantity signal of a fire phenomenon transmitted from the fire sensor side. be.

When applying the present invention to an analog fire alarm system, a microprocessor MP is installed in the receiver RE or repeater.
In addition to providing U and working RAM, sensors DE to R
OMI, ROM2, RAM1, and IF3 are relocated, and a program for polling a plurality of analog sensors DE to read physical quantity signals is added to the relocated ROM1. Further, the RAM 1 is provided for the number of connected analog sensors DE.

The analog detector DE stores a program that determines whether or not a call has been received from the reception IIIRE by polling, and when the call is received, reads a physical quantity signal from the fire phenomenon determination means FS and sends it to the receiver RE. A ROM is provided.

[Effects of the Invention] As described above, according to the present invention, when the sensor output level reaches the first predetermined level, the operation of the air conditioning equipment is actively stopped to prevent dilution of the physical quantity based on the fire phenomenon. This has the effect of making it possible to detect fires early.

゛Also, if the air conditioner is not determined to be a fire while the operation of the air conditioner is stopped for the first predetermined period of time, the air conditioner is operated for the second predetermined period of time, so that temporary phenomena can be avoided. In this case, the indoor environment quickly returns to normal and false alarms are prevented.

[Brief explanation of the drawing]

1A and 1B are graphs for explaining the present invention in detail, FIG. 2 is a block circuit diagram showing a fire alarm system according to an embodiment of the present invention, and FIG. 3 is a diagram showing the operation of FIG. 2. FIG. 4 is a flowchart for explaining the details of the sensor output level storage area RAM1 in FIG. 2. In FIG. is air conditioner, MPU is microprocessor, ROMI is program storage area, ROM2
is a storage area for various constants, FS is a fire phenomenon detection means, RA
M1 is a sensor output level storage area, and RAM2 is a work area. Crane IA diagram 1B

Claims (2)

[Claims] (1) A fire phenomenon detection means that detects a physical quantity based on a fire phenomenon and outputs a sensor output level, and determines that there is a fire when the sensor output level from the fire phenomenon detection means reaches a fire discrimination standard. A fire alarm device equipped with a fire determination means, comprising: a sensor output level determination means for determining whether or not the sensor output level has reached a first predetermined level in an air-conditioned environment; The air conditioning system is characterized by comprising an air conditioning stop means for stopping the air conditioning operation for a first predetermined time when the sensor output level determining means determines that the first predetermined level has been reached. Fire alarm system. (2) The air conditioning stop means detects that the sensor output level has reached the fire discrimination standard while the air conditioning operation is stopped for the first predetermined period of time by the air conditioning stop means. If the discrimination means does not discriminate,
The fire alarm device according to claim 1, wherein the air conditioning operation is performed for a second predetermined period of time.