Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
According to the embodiment of the invention, the smoke detection period of the smoke alarm is shortened when smoke is generated, whether the smoke is generated by naked fire is judged according to the change trend of the smoke concentration, and when the smoke is judged to be generated by the naked fire, the smoke alarm threshold value of the smoke alarm is reduced, the alarm sensitivity of the smoke alarm is increased, and the smoke alarm gives an alarm in advance.
Fig. 1 shows an implementation process of the open fire alarm detection method provided by the embodiment of the present invention, which is detailed as follows:
in step S101, when it is detected that the current smoke concentration satisfies the set concentration threshold, the current detection period of the smoke alarm is adjusted to a fast detection period, so as to accelerate the detection frequency of the smoke concentration.
The smoke alarm is generally powered by a battery, and in order to prolong the service life of the battery, under a normal standby condition, namely clean air, the smoke alarm detects smoke once according to preset time, for example, the smoke is detected once every 8 seconds, so that the power consumption can be saved, and the smoke detection is not influenced.
In order to improve the sensitivity of the smoke alarm to open fire alarm detection, the embodiment of the invention sets a quick detection period to accelerate the detection frequency of the smoke alarm, for example, the original detection of smoke for one time in 8 seconds is changed into the detection of smoke for one time in 2 seconds.
The system can set a smoke concentration threshold value entering a rapid detection period, and when the detected smoke concentration meets the smoke concentration threshold value, the detection period of the smoke alarm is adjusted to be the rapid detection period, so that the detection frequency of the smoke alarm to the smoke concentration is accelerated, the smoke alarm is convenient to detect the change of the smoke concentration more timely, and the alarm sensitivity is improved.
As an embodiment of the present invention, in order to ensure that the smoke alarm enters the rapid detection period in time and avoid alarm delay, the smoke concentration threshold may be adjusted as low as possible, for example, when smoke is detected or a small amount of smoke is generated, the smoke alarm may be adjusted to enter the rapid detection period.
In step S102, a smoke density increase rate is obtained according to the detected smoke density change amount and the corresponding time.
In the embodiment of the invention, the smoke concentration increasing rate is obtained to judge the smoke concentration variation trend so as to judge which fire generates the smoke. The smoke concentration increase rate can also be called as a smoke increase rate, and the larger the increment of the smoke concentration in unit time is, the larger the smoke concentration increase rate is, and the stronger the change trend of the smoke concentration is.
In real life, the smoke generated when a fire occurs is complex, the smoke concentration generated by open flame such as newspaper and plastic foam rises very fast, and the smoke concentration generated by wood and cotton rope burns in shade rises relatively slowly.
Practical studies show that the smoke produced by different fires has different change trends, for example, the smoke rising rates of open fire and smoldering fire have large difference.
Fig. 2 shows a typical open flame smoke rise curve, which is similar to smoke rise curves for wood open flame, PU open flame, etc., in which the smoke generated by an open flame, such as newspaper burning, can saturate the signal of the smoke alarm in a short time.
Fig. 3 shows the smoke rising curve of wood smoldering fire, and it can be seen from fig. 3 that more time is required from smoke generation to saturation than for open fire, and the smoke rising curves such as cotton rope smoldering and PU smoldering are similar to the above. .
Therefore, the smoke rise rate calculated according to the embodiment of the present invention can be used to reflect open fire and smoldering fire.
In the embodiment of the present invention, the rate of increase in smoke density is determined based on the increase in smoke density detected within a predetermined time.
The predetermined time is composed of a plurality of fast detection periods, for example, 10 fast detection periods are set, each fast detection period is 2 seconds, and the predetermined time is 20 seconds.
In step S103, when it is determined that smoke is generated by an open fire according to the smoke concentration increase rate, the smoke alarm threshold of the smoke alarm is lowered.
In the embodiment of the invention, when the detected smoke concentration increment reaches the set smoke concentration increment threshold value in the preset time, the smoke is judged to be generated by open fire.
Since time is at a premium for personnel to escape, many lives can be saved, perhaps in a few seconds. Therefore, when the smoke is judged to be generated by open fire according to the smoke concentration increase rate, the smoke alarm threshold value of the smoke alarm is reduced, so that the smoke alarm gives an alarm in advance or quickly, people are reminded in time, more escape time is reserved, and the safety of the people is guaranteed.
As an embodiment of the present invention, in determining whether smoke is generated by an open flame, it is possible to realize this by detecting the smoke concentration increase (electric signal increase) and the number of detections (detection time) at the same time. The system sets a smoke concentration increment threshold and a detection frequency threshold, and the detection is terminated when the smoke concentration increment threshold and the detection frequency threshold are reached first. If the smoke concentration increment reaches a set threshold value first, the detection times are smaller than the preset threshold value, and the smoke rising rate is high; if the detection times reach the set threshold value first, the smoke concentration increment is smaller than the preset threshold value at the moment, and the smoke rising rate is slow.
Fig. 4 shows an implementation flow of the open fire smoke determination provided by an embodiment of the present invention, which is detailed as follows:
in step 201, entering an open fire identification process;
in step 202, determining whether smoke is generated;
the smoke alarm can record the electric signal value under the clean air before leaving the factory, the signal value is relatively stable under the clean air, the electric signal value can be increased when smoke is generated, the smoke concentration is higher, the electric signal value is larger, the detected electric signal value exceeds the signal value under the clean air and exceeds a set threshold value, and then a small amount of smoke is generated.
In step 203, accelerating detection of smoke;
the smoke alarm is generally powered by a battery, and in order to prolong the service life of the battery, under a normal standby condition, namely under clean air, smoke is detected every 8 seconds, so that power consumption can be saved, and smoke detection is not influenced. When a small amount of smoke is detected, the smoke concentration is detected every 2 seconds instead.
In step 204, accumulating the number of smoke detections performed according to the fast detection period;
in the embodiment of the present invention, the number of detections may be accumulated from 0, and after every 2 seconds of detection, the number of detections may be increased by 1.
In step 205, the smoke concentration increment after each smoke detection is calculated;
in step 206, it is determined whether the smoke concentration increment reaches a preset smoke concentration increment threshold;
in step 207, if the smoke concentration increment reaches the preset smoke concentration increment threshold (the detection times do not reach the detection time threshold), it may be determined that the smoke is generated by an open fire, and the smoke alarm threshold of the smoke alarm is lowered.
Because the burning speed of open fire is fast, the time is very valuable for escaping, thereby reducing the smoke alarm threshold value of the smoke alarm, leading the alarm to give an alarm in advance and leading people to have more time to escape.
In step 208, if the smoke concentration increment does not reach the preset smoke concentration increment threshold, the smoke detection times are determined, and if the detection times do not reach the preset detection times threshold, the process returns to step 204 and continues to be executed according to the flow.
In step 209, if the detection frequency reaches the preset detection frequency threshold (the smoke concentration increment has not reached the preset threshold), it is determined that the smoke is generated by smoldering fire, and a normal smoke detection process is performed.
Figure 5 shows the structure of a smoke alarm provided by an embodiment of the invention, only the parts relevant to the embodiment of the invention being shown for ease of illustration.
In the embodiment of the present invention, the control unit 51 may be implemented by a single chip. Upon smoke detection, the control unit 51 turns on the photoemission circuit 52 to emit a light signal. When smoke is generated, due to the reflection and scattering effects of smoke particles, the photoelectric receiving circuit 53 receives an optical signal transmitted by the photoelectric transmitting circuit 52, converts the optical signal into an electric signal, the control unit 51 samples a smoke voltage value amplified by the signal amplifying circuit 54, compares the smoke voltage value with a smoke alarm threshold value set by a factory, and starts the sound-light alarm circuit 55 to give an alarm if the smoke voltage value is larger than the smoke alarm threshold value.
In the embodiment of the present invention, in order to reduce the power consumption of the smoke alarm, the control unit 51 automatically enters the sleep state during the non-detection period, and turns on the photoemission circuit 52 to emit the optical signal to perform the smoke detection when the predetermined detection period is reached.
In the embodiment of the present invention, the control unit 51 is configured with an open fire alarm detection device for detecting smoke generated by open fire, and when it is detected that the smoke is generated by open fire, the smoke alarm threshold of the smoke alarm is lowered to improve the alarm sensitivity of the smoke alarm, and when open fire occurs, the alarm is accelerated or advanced to ensure safety.
Fig. 6 shows a structure of an open fire alarm detection device according to an embodiment of the present invention, and for convenience of explanation, only a part related to the embodiment of the present invention is shown.
The detection period adjusting unit 61 is configured to adjust a current detection period of the smoke alarm to a fast detection period when it is detected that the current smoke concentration satisfies a set concentration threshold, so as to accelerate the detection frequency of the smoke concentration.
The smoke concentration increase rate acquisition unit 62 is configured to acquire a smoke concentration increase rate according to the detected smoke concentration change amount and the corresponding time.
The alarm threshold adjusting unit 63 is configured to reduce the smoke alarm threshold of the smoke alarm when it is determined that smoke is generated by an open fire according to the smoke concentration increase rate.
According to the embodiment of the invention, the smoke concentration detection period is adjusted, the smoke detection frequency is accelerated, the smoke generated by open fire is timely identified according to the smoke concentration change condition, the smoke alarm threshold value is correspondingly reduced, the alarm sensitivity of the smoke alarm to the open fire is improved, and the smoke alarm can give an alarm in advance or quickly, so that more escape time is reserved, and the safety of personnel is ensured.
In the embodiment of the present invention, the rate of increase in smoke density is determined based on the increase in smoke density detected within a predetermined time.
Fig. 7 shows a structure of an alarm threshold adjusting unit provided in an embodiment of the present invention, and for convenience of description, only a part related to the embodiment of the present invention is shown.
The detection number accumulation module 71 accumulates the number of smoke detections performed according to the above-described rapid detection period.
In the embodiment of the present invention, the number of detections may be accumulated from 0, and after every 2 seconds of detection, the number of detections may be increased by 1.
The smoke concentration increment calculation module 72 calculates the smoke concentration increment after each smoke detection.
The smoke concentration increment threshold judgment module 73 judges whether the smoke concentration increment reaches a preset smoke concentration increment threshold.
The detection threshold value judging module 74 judges whether the smoke detection frequency reaches a preset detection frequency threshold value when the smoke concentration increment does not reach the preset threshold value.
The open fire smoke recognition module 75 lowers the smoke alarm threshold of the smoke alarm when the smoke concentration increment threshold judgment module 74 judges that the smoke concentration increment reaches the smoke concentration increment threshold.
Because the burning speed of open fire is fast, the time is very valuable for escaping, thereby reducing the smoke alarm threshold value of the smoke alarm, leading the alarm to give an alarm in advance and leading people to have more time to escape.
Furthermore, a storage medium, in particular a computer readable storage medium, is provided, which stores one or more programs, which are executable by one or more processors to cause the one or more processors to perform the steps of any of the above-described open fire alarm detection methods.
According to the embodiment of the invention, the smoke concentration detection period is adjusted, the smoke detection frequency is accelerated, the smoke generated by open fire is timely identified according to the smoke concentration change condition, the smoke alarm threshold value is correspondingly reduced, the alarm sensitivity of the smoke alarm to the open fire is improved, and the smoke alarm can give an alarm in advance or quickly, so that more escape time is reserved, and the safety of personnel is ensured. The embodiment of the invention can reduce the smoke alarm threshold value, increase the sensitivity of the smoke alarm, judge the current fire trend according to the trend of smoke and reduce the possibility of false alarm.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.