JPH0734239B2 - Fire judgment method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fire determination method in a self-fire alarm system or the like.

[Background Art] Cigarettes are the second most common cause of building fires (first is arson). Therefore, the following things were discovered by studying how the ignition state caused by this cigarette changes under each condition.

In other words, when a lit cigarette is thrown into the garbage that has been thrown away from paper dust, the fire of the cigarette is transferred to another cigarette or paper dust.
In this case, tobacco burns gradually, but the paper waste is carbonized. And the amount of heat around the cigarette increases and the amount of smoke increases sharply. A few seconds after the amount of smoke increases sharply, it ignites and the amount of smoke decreases extremely. This causes a fire.

As shown in FIG. 3, when the change in smoke density up to the above-mentioned ignition was measured at the position X above and near the garbage Y, the change as shown in FIG. 4 (a) was obtained. In other words, after throwing the cigarettes into the garbage bag Y, it starts to smolder for a few minutes (a), this state continues for 10 minutes to a few tens of minutes (b), and in a few seconds after that, the amount of smoke increases sharply (c) and fires D), then the amount of smoke is reduced and the flame is increased (e). Here, in the period from (d) to (e '), garbage bag Y
The thing inside is burned on the surface, and if there is something burning around it, it will be burned.

By the way, when the above-mentioned ignition experiment was conducted in a closed room and the change in smoke density was measured on the ceiling surface, the measurement result as shown in FIG. 4 (b) was obtained. That is, on the ceiling surface, Fig. 4 (a)
Even if the amount of smoke increased during period (c), no air flow was generated, so the smoke did not reach the measurement position on the ceiling surface, and the measured value did not increase much (f). When the ignition (d) of FIG. 4 (a) occurs, an air flow is generated by the ignition, the ceiling surface is filled with smoke all at once, and the smoke density at the measurement point also increases (g).
This (g) period is several seconds. Then, after that, the smoke density decreases in a state where the past smoke and the newly generated smoke are mixed (H).

As described above, the change in the detected smoke density deviates with time between the ceiling surface and the vicinity of the dusty bag Y. Since the normal smoke sensor is provided on the ceiling surface, the change in smoke density as shown in FIG. 4 (b) is detected. With the conventional smoke sensor, a fire is detected as soon as the detected smoke concentration exceeds a specified value.
Period (g) when the detected smoke concentration rapidly increases as shown in Fig. 4 (b)
If it is several seconds, and then there is a period (h) when the smoke concentration decreases, the smoke increase is transient and cannot be detected by the conventional method, and it may be detected only when it burns to another one. However, there was a problem that the fire detection could not be reliably performed in the early stage of the fire caused by the cigarette fire.

[Object of the Invention] The present invention has been made in view of the above problems, and an object of the present invention is to perform a fire determination in accordance with a pattern of fire occurrence due to a cigarette fire, and to initiate a fire occurrence due to a cigarette fire. It is to provide a fire judging method capable of surely detecting and judging in stages.

DISCLOSURE OF THE INVENTION FIG. 1 is a conceptual diagram of a system using the present invention. In the present invention, an analog type smoke sensor 1 that generates an output at a level according to a change in detected smoke density is used, and sensor outputs are multiplexed. Is transmitted as data to the receiver 2, or is transmitted as a change in the line voltage via the line, and the output information of the smoke sensor 1 is given to the receiver 2 and the receiver 2 outputs the information. Based on this, the smoke density detected by the smoke sensor 1 is discriminated.

Next, the operation of the embodiment will be described based on the flowchart of FIG.

First, the receiver 2 verifies the difference between the output of the smoke sensor 1 and the normal detection value to determine whether or not the detected smoke concentration is slightly increasing, and it is determined that this determination is increasing. If so, it is determined whether or not the increase is continuous for a predetermined time or longer. If it is continuous, that is, if it is determined that smoke is being generated, the output level of the smoke sensor 1 suddenly rises. Determine whether it is increasing. Alternatively, if it is determined that the smoke concentration is higher than before even if it is determined that the continuity is not determined (that is, the smoke introduced into the smoke sensor 1 may be temporarily interrupted depending on the flow of air. There is a case where continuity is not always obtained, but even in that case, if the smoke concentration increases after a certain amount of time, it is judged that the smoke concentration continues to increase. ) The process moves to the process of determining whether the output level of the smoke sensor 1 has risen sharply, and if there is a sharp rise, the receiver 3 determines that a fire has occurred and performs processing operations such as a fire alarm.

In this way, by providing a fire determination process that matches the fire occurrence pattern due to the cigarette fire, from smoke generation to ignition, in addition to the normal fire determination process, it is possible to reliably detect the fire occurrence due to the cigarette fire at the initial stage. .

EFFECTS OF THE INVENTION The present invention uses the analog smoke sensor that generates an output at a level according to the detected smoke concentration as described above, and determines whether or not the detected smoke concentration increases with respect to the normal state. If there is a judgment of increase in the first process and the first process, a second process of judging whether the increase is continuous or not, and if there is a judgment of continuity in the second process, a rapid rise. The third step is to determine whether there is an increase in the smoke concentration. In the third step, it is determined that a fire has occurred when there is a sharp rise in smoke concentration. It is possible to judge the occurrence of a fire, and it is difficult to simply discriminate the smoke density. Play. That is, in the present invention,
The process of detecting that the smoke concentration has increased from the normal state, the process of detecting that smoke is continuously detected after that, and the process of detecting the rapid increase in the rate of change of smoke concentration
In one process, the fire occurrence is judged based on the smoke density, and before the smoke density suddenly rises due to the fire occurrence, 2
By performing the preliminary determination of the stage, it is possible to detect the occurrence of the fire immediately after the occurrence of the fire and the smoke concentration rapidly increases, and as a result, it is possible to detect the occurrence of the fire early. Moreover, since the occurrence of a fire is determined in three stages, there is an effect that erroneous determination can be prevented.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram using the present invention, FIG. 2 is a flow chart of the above-mentioned embodiment, FIG. 3 is an explanatory view of an experiment of an ignition process by a cigarette fire, and FIG. 4 is the same smoke concentration and time. It is a measurement result explanatory view which shows a relationship, 1 is a smoke sensor, 2 is a receiver.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shigeki Shimomura, 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works, Ltd. (72) Takahiro Azumaya, 1048, Kadoma, Kadoma, Osaka Prefecture, Matsushita Electric Works, Ltd. (56) References JP 51-139299 (JP, A) JP 59-201193 (JP, A) JP 57-27109 (JP, Y2)

Claims (1)

[Claims] 1. A first process for determining whether or not there is an increase in the detected smoke density with respect to a normal state by using an analog type smoke sensor that generates an output of a level according to the detected smoke density, and a first step.
If there is a judgment of increase in the process of, there is a second process that judges whether the increase is continuous, and if there is a judgment of continuity in the second process, whether there is a sharp rise in rise. And a third process for determining whether a fire has occurred when it is determined that the smoke concentration has risen sharply in the third process.