Smoke fire detector detection method and system

Abstract

The application provides a smoke fire detector detection method and system, belonging to the technical field of detection, solving the problem that the system may alarm when the overall smoke density of the test box has not reached the expected value if the detector samples near the aerosol peak value each time, and the internal detection value is higher than the actual time average smoke level. The method comprises: controlling an aerosol generating device to deliver aerosol to a fire detector test box, the aerosol generating device outputs aerosol through a plurality of smoke generating pulses by an electromagnetic pulse valve; changing the time interval between adjacent smoke generating pulses according to a predetermined pulse coding sequence to form a non-equidistant smoke generating pulse sequence; recording the state change moment corresponding to the state output information of the measured smoke fire detector; determining the time correlation degree between the state change of the measured smoke fire detector and the predetermined pulse coding sequence; and predicting whether the detection result has a system deviation according to the correlation degree.

Description

Technical Field

[0001] This application relates to the field of detection technology, and in particular to a detection method and system for smoke detectors. Background Technology

[0002] During the detection process of a smoke detector, the aerosol generator controls the aerosol output through an electromagnetic pulse valve. Each time the electromagnetic pulse valve opens, it releases one unit of aerosol. The smoke detector under test may also periodically drive a light source according to its own clock and collect scattered light.

[0003] If the pulse period of the electromagnetic pulse valve and the sampling period of the detector form a fixed relationship, the detector may continuously sample at the peak of the local smoke concentration, or continuously sample at the trough between the peaks. In this case, different test benches may obtain different alarm results even if the average smoke density is the same. Summary of the Invention

[0004] This application provides a smoke detector detection method and system, which can solve the problem in traditional detection methods where if the detector samples near the aerosol peak each time, its internal detection value will be higher than the actual average smoke level over time, causing the system to alarm before the overall smoke density in the test chamber reaches the expected value.

[0005] The first aspect of this application provides a method for detecting smoke fires using a smoke detector, including: The smoke detector under test is placed inside the fire detector test chamber. An aerosol generator is controlled to deliver aerosol into the fire detector test chamber. The aerosol generator outputs the aerosol with multiple smoke-generating pulses through an electromagnetic pulse valve. The time interval between adjacent smoke-generating pulses is changed according to a predetermined pulse coding sequence, so that the multiple smoke-generating pulses form a non-equal interval smoke-generating pulse sequence. During the non-equal interval smoke-generating pulse sequence, the status output information of the smoke detector under test is collected, and the time of status change corresponding to the status output information is recorded. Based on the output time of each smoke-generating pulse and the time of the state change, determine the degree of time correlation between the state change of the smoke detector under test and the predetermined pulse coding sequence; If the time correlation reaches a preset correlation condition, it is determined that the current detection process is affected by the periodic aliasing between the smoke-generating pulse and the internal sampling period of the smoke detector under test. The predetermined pulse coding sequence is changed or a phase perturbation is applied to the output time of the smoke-generating pulse to re-detect the smoke detector under test.

[0006] A second aspect of this application provides a smoke detector detection system, comprising: The delivery unit is used to place the smoke detector under test in the fire detector test chamber and control the aerosol generator to deliver aerosol into the fire detector test chamber. The aerosol generator outputs the aerosol with multiple smoke-generating pulses through an electromagnetic pulse valve. The adjustment unit is used to change the time interval between adjacent smoke-generating pulses according to a predetermined pulse coding sequence, so that the multiple smoke-generating pulses form a non-equal interval smoke-generating pulse sequence. The acquisition unit is used to acquire the status output information of the smoke detector under test during the action of the non-equal interval smoke-generating pulse sequence, and record the time of status change corresponding to the status output information; The determining unit is used to determine the degree of time correlation between the state change of the smoke detector under test and the predetermined pulse coding sequence based on the output time of each smoke-generating pulse and the state change time. The analysis unit is used to determine, when the time correlation reaches a preset correlation condition, that the current detection process is affected by the periodic aliasing between the smoke-generating pulse and the internal sampling period of the smoke detector under test, and to change the predetermined pulse coding sequence or apply a phase perturbation to the output time of the smoke-generating pulse in order to re-detect the smoke detector under test.

[0007] A third aspect of this application provides an electronic device, including a memory and a processor, wherein the processor is used to execute a computer program stored in the memory to implement the steps of the above-described smoke detector detection method.

[0008] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the smoke detector detection method described above.

[0009] In summary, the smoke detector detection method provided in this application, by changing the time interval between adjacent smoke-generating pulses, continuously shifts the aerosol peak relative to the detector's internal sampling time. This makes it difficult for the detector to consistently capture local peaks, thus reducing the possibility of systematically underestimating the alarm smoke density. Conversely, if the detector originally sampled continuously between two aerosol peaks, non-equally spaced pulses will also cause some smoke peaks to move to near the sampling time, thereby reducing the possibility of late or missed alarms. Furthermore, testing personnel typically cannot directly read the detector's internal sampling clock. This solution does not require disassembling the detector or modifying its hardware or software. Instead, it determines whether the internal sampling process is affected by the external pulse timing by using the time relationship between the known time code of the external input and the detector's output state. In this application, the predetermined pulse code sequence is equivalent to applying an aerosol input with a recognizable time structure to the detector under test. If the detector output repeatedly shows changes corresponding to the same time structure, it is possible to deduce from the external response that the internal sampling and judgment process is affected by this input timing. Traditional methods may only control the total aerosol volume and the rate of increase in test chamber smoke density per unit time. Under the same average quantity, fixed-interval pulses and unequal-interval pulses may be considered equivalent inputs. However, for periodically sampled detectors, the two are not necessarily equivalent. This scheme modifies the pulse timing while maintaining the correspondence of average aerosol output as much as possible, thus distinguishing the response changes caused by the average smoke supply from those caused by the pulse phase relationship. This improves the ability to interpret error sources. Pipe length, electromagnetic pulse valve response time, airflow velocity, and controller start-up timing may differ in different test chambers. These differences will change the phase when the smoke-generating pulse arrives at the detector. When using fixed-interval smoke generation, the same detector may repeatedly capture smoke peaks on one device and smoke troughs on another. This scheme, by identifying time correlations and rearranging the smoke generation time, can reduce the impact of initial phase differences on the detection results. Therefore, the response time and alarm smoke density of the same detector in different detection devices or different batches are more comparable. When the time correlation reaches a preset correlation condition, this scheme does not simply correct a certain smoke density value, but changes the pulse code or applies phase perturbation before re-detecting. Re-detection is equivalent to changing the temporal conditions that caused the suspicious correspondence. If the original detection result was indeed affected by periodic aliasing, the timing of the state change and the detection result will usually change accordingly after the phase relationship is changed; if the original correspondence only occurred by chance, it will not be stably reproduced in the re-detection. This can avoid incorrectly evaluating the detector due to a single accidental phase coincidence. Low-power smoke detectors typically have longer sampling intervals and are more susceptible to the timing of discrete smoke pulses. Some intelligent detectors also change the sampling frequency after the smoke signal increases, making their internal sampling state more complex.Non-equal interval pulse sequences do not presuppose that the detector has only one fixed sampling period. Instead, they continuously change the pulse phase through multiple different time intervals. Therefore, they can detect aliasing caused by fixed period sampling and also expose the timing sensitivity of the detector after changing the sampling frequency under different states.

[0010] Correspondingly, the systems, electronic devices, and computer-readable storage media provided in the embodiments of the present invention also have the above-mentioned technical effects. Attached Figure Description

[0011] Figure 1 A schematic flowchart illustrating a possible smoke detector detection method provided in an embodiment of this application; Figure 2 A schematic structural block diagram of a possible smoke detector detection system provided in this application embodiment; Figure 3 A schematic diagram of the hardware structure of a possible smoke detector detection system provided in this application embodiment; Figure 4 A schematic structural block diagram of a possible electronic device provided in an embodiment of this application; Figure 5 This is a schematic structural block diagram of a possible computer-readable storage medium provided for embodiments of this application. Detailed Implementation

[0012] This application provides a smoke detector detection method and related equipment, which can solve the problem in traditional detection methods where, if the detector samples near the aerosol peak each time, its internal detection value will be higher than the actual average smoke level over time, causing the system to alarm before the overall smoke density in the test chamber reaches the expected value.

[0013] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The technical solutions of the embodiments of this application will now be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them.

[0014] Please see Figure 1 The flowchart below illustrates a smoke detector detection method provided in this application embodiment. The method may specifically include: S110-S150.

[0015] S110, the smoke detector under test is placed inside the fire detector test chamber, and the aerosol generator is controlled to deliver aerosol into the fire detector test chamber. The aerosol generator outputs the aerosol with multiple smoke-generating pulses through an electromagnetic pulse valve.

[0016] S120, the time interval between adjacent smoke-generating pulses is changed according to a predetermined pulse coding sequence, so that the multiple smoke-generating pulses form a non-equal interval smoke-generating pulse sequence.

[0017] S130, during the action of the non-equal interval smoke-generating pulse sequence, the status output information of the smoke detector under test is collected, and the time of status change corresponding to the status output information is recorded.

[0018] S140, based on the output time of each smoke-generating pulse and the state change time, determine the degree of time correlation between the state change of the smoke detector under test and the predetermined pulse coding sequence.

[0019] S150, if the time correlation reaches the preset correlation condition, it is determined that the current detection process is affected by the periodic aliasing between the smoke-generating pulse and the internal sampling period of the smoke detector under test, and the predetermined pulse coding sequence is changed or a phase perturbation is applied to the output time of the smoke-generating pulse to re-detect the smoke detector under test.

[0020] Understandably, the aerosol generator controls aerosol output via an electromagnetic pulse valve. Each time the electromagnetic pulse valve opens, it releases one unit of aerosol. Although the aerosol diffuses and mixes after passing through the delivery pipeline and entering the fire detector test chamber, the aerosol clusters formed by each pulse may still retain local concentration peaks within a certain time scale. Therefore, the smoke state actually encountered by the smoke detector under test is not necessarily a completely smooth, continuously rising smoke density, but may exhibit several local fluctuations superimposed on an overall upward trend. For example, the average smoke density in the test chamber continuously increases, but near the smoke inlet of the detector, each smoke-generating pulse will create a short period of increased smoke density, followed by a decrease. Conventional optical smoke densitometers may use a long optical path or averaging over a certain time period, and their output values ​​can well characterize the overall smoke density of the test chamber, but may not be able to completely display the instantaneous smoke density peak at the smoke inlet of the detector. The optical detection unit inside the detector under test may sample precisely during these peaks or peak intervals.

[0021] Furthermore, it's important to note that smoke detectors, in order to reduce power consumption, suppress noise, and extend the lifespan of the light source, typically do not continuously illuminate their internal light-emitting devices. Instead, they may perform detection according to an internal sampling cycle. At each sampling moment, the detector briefly drives the light-emitting device, reads the scattered light signal obtained by the receiver, and then performs baseline correction, filtering, continuous count confirmation, or alarm judgment. The internal sampling cycle of the detector under test is generally not directly disclosed to the detection equipment, and different models, different operating stages, and even different software versions of the same model may use different sampling cycles. Some detectors may also automatically shorten the sampling cycle when the detected value approaches the warning threshold. If the electromagnetic pulse valve outputs aerosols according to a fixed cycle, and the detector also samples according to a fixed cycle, a stable phase relationship may be established between the two. For example, if the smoke pulse is output every two seconds, the detector samples once per second, and the time required for the aerosol to be delivered from the pulse valve to the vicinity of the detector is relatively stable, then the detector may always sample when the local peak of the aerosol is reached. Conversely, if the initial phases of the two are different, the detector may also continuously sample between two aerosol peaks. This phenomenon is not a simple random fluctuation. As long as the two cycles and their phase relationship remain stable, the error will accumulate in the same direction throughout the detection period, eventually manifesting as the detector alarming too early or too late, or the detection results of different tests changing with the initial start time.

[0022] Therefore, it is understandable that, to identify the aforementioned effects, this scheme does not allow the electromagnetic pulse valve to continuously generate smoke at identical time intervals. Instead, it pre-sets a pulse coding sequence with time intervals varying in a specific order. This coding does not require the smoke-generating pulses to carry data in the sense of digital communication; rather, it uses the time interval between adjacent smoke-generating pulses as an identifiable temporal feature. For example, time intervals of 0.8 seconds, 1.3 seconds, 0.9 seconds, 1.6 seconds, and 1.1 seconds can be used sequentially. The arrangement of these intervals constitutes the predetermined pulse coding sequence. By using a non-equidistant timing sequence, even if the detector has an unknown but fixed internal sampling period, the phase of each smoke-generating pulse relative to the internal sampling time will gradually change. This makes it difficult for the detector to consistently capture aerosol peaks throughout the detection period, nor is it easy to consistently avoid aerosol peaks. More importantly, the non-equidistant pulse sequence has an identifiable temporal structure. If the detector's state output changes continuously follow this temporal structure, it can be inferred that the smoke fluctuations formed by the smoke-generating pulses have entered the detector's sampling and state judgment process. The control system knows the output time of each smoke-generating pulse and continuously collects the status output information of the detector under test, thus allowing comparison of the correspondence between the smoke-generating pulse timing and the detector status change timing. Status output information can include alarm contact status, warning status, fire alarm status, analog output, smoke measurement values ​​in digital communication messages, status levels, or other outputs that characterize changes in internal detection status. The status change time can be the moment the detector transitions from a normal state to a warning state, from a warning state to an alarm state, or the moment the analog output crosses the boundary between different levels. When determining the degree of time correlation, it is not advisable to only compare whether the smoke-generating pulse output time is close to the alarm time, because the aerosol also needs to undergo pipeline transportation, mixing in the enclosure, and smoke entry into the detector. In practical implementation, transport delays and possible pulse broadening can be included in the comparison. That is, the comparison should focus on whether the detector status change times are concentrated within a specific time range after each smoke-generating pulse reaches the detector position. If the rise in detector state variables, level transitions, or alarm confirmations consistently occur at similar phase positions after the smoke-producing pulse, and this correspondence is significantly higher than that that might occur randomly, it indicates that the detector's state changes are significantly affected by the pulse timing. The presence of time correlation in a single detection does not necessarily prove the existence of periodic aliasing; it could also be caused by random fluctuations or the overall rise of aerosols. Therefore, this scheme does not directly use the detection result when the time correlation reaches the preset correlation condition. Instead, it changes the pulse coding sequence or applies a phase perturbation to the smoke-producing pulse output time, and then re-detects. Changing the pulse coding sequence refers to altering the values ​​or order of the time intervals. For example, if a longer interval in the original sequence occurs after the third pulse, it can be adjusted to occur after the first pulse during re-detection.Applying phase perturbation refers to advancing or delaying at least some smoke-producing pulses without changing the number of pulses or the overall smoke production. For example, applying time offsets of tens to hundreds of milliseconds to different pulses changes their position relative to the detector's internal sampling time. If changing the encoding or applying phase perturbation significantly weakens the original state change correlation, and the detection results change accordingly, it further demonstrates that the original detection results were affected by a fixed phase relationship. If the time correlation no longer meets the preset correlation condition after re-detection, the detector performance can be evaluated with less impact from periodic aliasing.

[0023] For example, the smoke detector under test can be installed in a designated position within the fire detector test chamber, ensuring that the detector's installation direction, smoke inlet orientation, and installation height meet the testing requirements. The detector's status output is connected to the testing controller. For detectors with relay outputs, the relay contact status can be collected; for detectors with communication interfaces, normal, warning, alarm, and fault statuses can be read; for detectors capable of outputting simulated smoke quantities, their output values ​​can be recorded at a predetermined sampling frequency. Before formal smoke generation, the test chamber is cleaned and vented to ensure the background smoke density is within acceptable limits. Subsequently, the wind speed and temperature within the test chamber are adjusted to target conditions and maintained within the corresponding allowable deviation range. This step reduces the interference of wind speed or temperature changes on aerosol transport delay.

[0024] For example, the aerosol generator controller and the detector status acquisition device use a unified timing reference, or record timestamps that can be converted to the same time axis. Whenever the solenoid pulse valve receives an opening command, the command time of the smoke-generating pulse is recorded. If there is a non-negligible delay in the mechanical opening of the solenoid pulse valve, this delay can be pre-measured, and the command time can be corrected to the actual aerosol release time. The detector status acquisition device continuously acquires output at time intervals that can distinguish state changes. For example, if the internal sampling period of the detector is expected to be in the range of hundreds of milliseconds to several seconds, the status acquisition interval can be set significantly shorter than this range to avoid over-quantification of state change times.

[0025] For example, firstly, the total aerosol output required within a statistical period is determined based on the target smoke supply rate. Then, without causing the average smoke supply rate to deviate significantly from the target value, the smoke-producing pulses are arranged to be output at non-equidistant intervals. For instance, if eight smoke-producing pulses are planned to be output within a ten-second statistical period, the intervals between adjacent pulses can vary in the order of 0.8 seconds, 1.4 seconds, 0.9 seconds, 1.2 seconds, 0.7 seconds, 1.6 seconds, and 1.0 seconds. This coding can be repeated in the next statistical period to accumulate multiple observation samples; alternatively, a different known coding can be used to avoid generating new periodicity after prolonged repetition. If different time intervals cause changes in smoke production within the statistical period, the valve opening duration of individual pulses can be adjusted to ensure that the total aerosol output within each statistical period corresponds to each other. This helps to distinguish the pulse timing variations from the average smoke supply variations as much as possible. The predetermined pulse coding sequence can meet the following requirements: First, the time intervals are not entirely identical, so that the smoke production time does not form a single fixed cycle. Second, the time intervals have sufficient differences to allow the control system to recognize the temporal characteristics of the pulse coding. Third, the shortest time interval shall not be less than the time required for the electromagnetic pulse valve to complete one reliable opening and closing. Fourth, the longest time interval shall not cause a prolonged stagnation in the smoke density increase process of the test chamber that does not meet the testing requirements.

[0026] For example, during the execution of a non-equal interval smoke-generating pulse sequence, the status output information of the detector under test is continuously acquired. For detectors with multi-level status outputs, the following moments can be recorded separately: the moment when the output value first significantly deviates from the background value, the moment when the warning state is entered, the moment when the alarm preparation state is entered, and the moment of the formal alarm. Multiple status change moments can provide richer time-related information than a single alarm moment. For detectors with only one alarm contact, the non-equal interval smoke-generating process can be repeated under the same detection conditions multiple times, and the alarm moment can be recorded each time. Subtle changes in the status output before the alarm can also be included in the acquisition, as long as these changes can be obtained through the interface provided by the detector. It should be noted that the status change moments are determined based on the actual output of the detector under test, not based on the moment when the smoke density in the test chamber exceeds a certain threshold. These two represent the environmental input and the response of the tested object, respectively, and should not be confused.

[0027] For example, after the smoke pulse is output from the electromagnetic pulse valve, it needs to pass through the aerosol delivery pipeline, the test chamber inlet, and the flow area inside the chamber before reaching the detector under test. Therefore, the transport delay of the aerosol from the generating device to the detector location can be predetermined. One implementation is to set up a rapid smoke detection position near the detector for test calibration. After outputting a single low-dose pulse, the time when the smoke density at this position begins to increase and reaches its peak is recorded, thereby determining the pulse arrival delay and the width of the arrival period. If no additional detection position is set up, the transport delay can also be estimated based on the pipeline length, airflow velocity, and flow path inside the test chamber, and corrected through multiple tests. Since the aerosol pulse diffuses during transport, the pulse arrival period can be used for actual comparison, rather than being regarded as an instantaneous moment without duration.

[0028] For example, using the arrival time of each smoke-generating pulse after transport delay correction as a benchmark, the time difference between each detector state change moment and its preceding adjacent smoke-generating pulse is calculated. If the time differences corresponding to multiple state change moments are concentrated within a narrow range, it indicates that the detector state changes are concentrated in a specific phase after the smoke-generating pulse. For example, if multiple state level changes are concentrated in the range of 200 to 350 milliseconds after the expected arrival of the aerosol pulse, while state changes rarely occur in other phase ranges, then the state changes can be considered to have obvious phase concentration. In another implementation, a predetermined pulse coding sequence can be converted into a pulse time function, and the detector state output information can be converted into a state change time function. The correlation between the two can be calculated under multiple candidate delay values. If a significant correlation peak appears at a certain delay value, and this delay value matches the actual aerosol transport and the time required for the detector to enter the smoke, then the correlation result can be considered to have physical meaning. The preset correlation conditions can comprehensively consider the correlation coefficient, the concentration of the state change phase, the difference between the correlation peak and the correlation value at other delay positions, and the effective number of state changes that achieve the correlation relationship. This can avoid incorrectly determining cycle aliasing simply because an alarm moment happens to be close to a smoke-generating pulse.

[0029] For example, when the time correlation reaches a preset correlation condition, the control system marks the current detection process as potentially affected by periodic aliasing. In this case, it is not advisable to directly evaluate the detector performance based on the current alarm time and alarm smoke density. Re-detection can be performed in either of the following ways: The first way is to change the pulse coding sequence. For example, rearrange the time intervals in the original code, or use a different set of time intervals. The average number of pulses and the average aerosol output after re-coding can still remain within acceptable limits to reduce changes in detection conditions. The second way is to apply phase perturbation. For example, based on the original output time, delay the first part of the pulses by 80 milliseconds, advance the second part of the pulses by 120 milliseconds, and apply different time offsets to the remaining pulses. The different offsets should be determined within the range that does not cause overlap of adjacent pulses and does not exceed the solenoid valve's actuation capability. After changing the coding or applying phase perturbation, the detector status output is collected again, and the time correlation is re-determined. If the correlation is lower than the preset correlation condition, it indicates that the detector status change is no longer stably dependent on the specific phase of the smoke-generating pulse. The response time, alarm smoke density, or whether an alarm is normal can be determined using the re-detection results. If the preset conditions are still met after re-detection, the encoding or perturbation method can be changed again until a detection process that does not meet the relevant conditions is obtained, or the detector can be marked as having significant sensitivity to the temporal structure of pulse smoke.

[0030] In some examples, it also includes: If the time correlation obtained by retesting does not meet the preset correlation condition, in at least two retesting processes, the aerosol average output rate, the wind speed and temperature in the fire detector test chamber are respectively within the corresponding preset deviation range, and different pulse coding sequences or different phase perturbation methods are used. When the time correlation obtained from at least two re-detections does not meet the preset correlation condition, the response time and alarm smoke density of the smoke detector under test are determined based on the alarm time of the smoke detector under test and the smoke density corresponding to the alarm time in each re-detection. When the time correlation obtained from any re-detection reaches the preset correlation condition, the alarm time and alarm smoke density of the corresponding detection process are marked as invalid detection data affected by periodic aliasing.

[0031] It is understandable that if the time correlation is found to meet the preset correlation condition in the initial detection, a single re-detection is insufficient to completely rule out random factors. For example, after changing the pulse coding sequence, the time correlation obtained in the re-detection may drop below the preset correlation threshold. However, this drop could be due to the new pulse timing effectively disrupting the stable phase relationship between the smoke-generating pulse and the detector's internal sampling period, or it could be due to changes in the test chamber wind speed, a shift in the average aerosol output rate, temperature altering the aerosol transport state, or the alarm timing being affected by random noise. Therefore, the absence of significant time correlation in a single re-detection is not necessarily sufficient to prove that the corresponding alarm result has escaped the influence of periodic aliasing. This example further sets up at least two re-detections, ensuring that the average aerosol output rate, test chamber wind speed, and temperature in each re-detection are within their respective preset deviation ranges. The aim is to ensure that the re-detections primarily change the time structure of the smoke-generating pulse, while minimizing changes to the environmental and smoke supply conditions that determine the detector's basic response level. Different pulse coding sequences refer to different arrangements of adjacent smoke-generating pulse time intervals used in different re-detections; different phase perturbation methods refer to at least some smoke-generating pulses using different advance or delay amounts. Thus, each re-detection will result in the smoke-generating pulse being in a different phase relationship relative to the detector's internal sampling time. If the time correlation of at least two re-detections does not meet the preset correlation condition, it indicates that under different pulse time structures, the detector's state changes are not stably concentrated on a specific phase of the smoke-generating pulse. In this case, the possibility of the re-detection results being affected by periodic aliasing can be considered significantly reduced, and therefore the detector's response time and alarm smoke density can be determined based on the alarm time and corresponding smoke density in each re-detection. Conversely, if any re-detection still meets the preset correlation condition, it indicates that under the pulse time structure used in that detection, the detector's state changes are still significantly affected by a specific phase of the smoke-generating pulse. The alarm time and alarm smoke density obtained from this detection cannot reliably characterize the detector's true response performance in a continuous or statistically stable smoke environment, and therefore should be marked as invalid detection data. It should be noted that marking a certain data as invalid is not equivalent to deeming the tested smoke detector unqualified. This marker only indicates that the alarm result was affected by periodic aliasing and cannot be directly used as an evaluation basis for response time or alarm smoke density.

[0032] For example, after the initial test, if the time correlation reaches a preset correlation condition, the test control system will initiate a retest process.

[0033] In the first re-detection, a first candidate pulse coding sequence can be used. For example, the time interval between adjacent smoke-producing pulses can be set to 0.8 seconds, 1.3 seconds, 1.0 seconds, 1.6 seconds, and 0.9 seconds, respectively. In the second re-detection, a second candidate pulse coding sequence can be used, for example, setting the time interval between adjacent smoke-producing pulses to 1.4 seconds, 0.9 seconds, 1.5 seconds, 0.8 seconds, and 1.0 seconds, respectively.

[0034] If a phase perturbation method is used, the first re-detection can advance or delay some smoke-generating pulses by the first set of time offsets, and the second re-detection uses a second set of time offsets different from the first set. Each time offset should be limited to not causing overlap of adjacent smoke-generating pulses and not disrupting the number of pulses and the total aerosol output within the preset statistical period.

[0035] During each retest, the average aerosol output rate, test chamber wind speed, and temperature are monitored. For example, the average aerosol output rate of each retest can be limited to a preset rate deviation range near the target smoke generation rate, the wind speed can be limited to a preset wind speed deviation range near the target wind speed, and the temperature can be limited to a preset temperature deviation range near the target temperature. After each retest, the following are obtained: the pulse-coded sequence or phase perturbation method used in this test; the actual output time of each smoke-generating pulse; the state change time and alarm time of the tested detector; the smoke density corresponding to the alarm time; and the time correlation degree corresponding to this test. If the time correlation degree of two retests does not meet the preset correlation condition, the response time can be determined based on the alarm times of the two tests. The response time can be retained as two independent measurements, or a representative value can be determined according to predetermined statistical rules. The alarm smoke density can also be determined based on the smoke density corresponding to the two alarm times. The core requirement here is that the data used to determine the final result should all come from a test process that does not exhibit significant periodic aliasing. If the first re-detection fails to meet the preset correlation conditions, but the second re-detection does, the alarm time and alarm smoke density of the second re-detection should be marked as invalid. Although the data from the first re-detection does not show a significant correlation, since the scheme requires that the detection result be determined only after at least two re-detections fail to meet the preset correlation conditions, the third encoding or third phase perturbation method can be used to perform the detection to obtain another set of data that is not significantly affected by periodic aliasing. If multiple re-detections meet the preset correlation conditions, the invalid data and their corresponding pulse time structures can be retained to illustrate that the detector has a significant time-series sensitivity to discrete pulse smoke supply methods, but these invalid data should not be used directly to calculate the detector's response time and alarm smoke density.

[0036] In some examples, changing the time interval between adjacent smoke-producing pulses according to a predetermined pulse coding sequence includes: The time interval between each adjacent smoke-producing pulse is selected sequentially from a plurality of preset time intervals according to the predetermined pulse coding sequence; Based on the target smoke addition rate and the preset statistical period, the aerosol output corresponding to each smoke production pulse within the preset statistical period is determined, so that the total aerosol output within the preset statistical period meets the target smoke addition rate, and the average aerosol output rate corresponding to different preset statistical periods is within the preset rate deviation range.

[0037] It is understandable that changing the time interval between adjacent smoke-generating pulses according to a predetermined pulse coding sequence essentially sets the time structure of aerosol input into a recognizable and non-uniformly spaced form. Multiple preset time intervals can be understood as a set of allowed time interval values. For example, time intervals of 0.8 seconds, 1.0 seconds, 1.3 seconds, and 1.6 seconds can be preset. The predetermined pulse coding sequence specifies the selection order of these time intervals, thereby determining the output time of each smoke-generating pulse. This coding method must create a non-uniformly spaced structure sufficient to change the pulse phase, but it must not cause significant changes in the average smoke addition rate during different detection processes. Otherwise, when the detector alarm time or alarm smoke density changes, it will be impossible to determine whether the change comes from a change in pulse timing or from a change in the aerosol output per unit time. Therefore, this example determines the aerosol output corresponding to each smoke-generating pulse using a preset statistical time period. Even if the pulse interval within a certain statistical time period is long or short, the total aerosol output within that statistical time period can be adjusted to meet the target smoke addition rate by adjusting the output of each pulse within that time period. For example, the target smoke addition rate can be expressed as the amount of aerosol that should be input into the test chamber per unit time. For a statistical period of ten seconds, the total aerosol output required within those ten seconds can be determined based on the target smoke addition rate, and then the total output can be distributed among multiple smoke-generating pulses within that statistical period. The average aerosol output rate corresponding to different statistical periods is within a preset rate deviation range, meaning that although the pulse times within each statistical period may differ, the aerosol output level per unit time is essentially consistent. Therefore, the pulse time structure becomes the main variable factor between each detection process.

[0038] For example, firstly, the time interval range within which the electromagnetic pulse valve can reliably operate is determined. The preset time interval should not be shorter than the time required for the electromagnetic pulse valve to complete one opening, closing, and recovery cycle, nor should it be long enough to stop the smoke density in the test chamber from increasing for an extended period. Subsequently, multiple preset time intervals are set within the allowable range. For example, four time intervals can be set: 0.7 seconds, 1.0 seconds, 1.4 seconds, and 1.9 seconds. The predetermined pulse coding sequence can specify that the time intervals between adjacent smoke-generating pulses are selected in the order of 1.0 seconds, 1.9 seconds, 0.7 seconds, 1.4 seconds, 1.0 seconds, and 0.7 seconds. The control system accumulates each time interval according to the coding sequence to obtain the planned output time of each smoke-generating pulse. If the first smoke-generating pulse is output at the beginning of the statistical period, the second pulse can be output one second later, the third pulse 1.9 seconds later, and subsequent pulses are output sequentially according to the time intervals determined by the coding. Then, the total aerosol output required for the statistical period is determined based on the target smoke addition rate and the length of the statistical period. For example, if the target smoke generation rate is one predetermined aerosol metering unit per second, and the statistical period is ten seconds, then the target total output for that statistical period is ten metering units. If five smoke-generating pulses are arranged within this statistical period, each pulse can output two metering units; alternatively, different output quantities can be allocated based on the time intervals between different pulses. For example, pulses before or after longer time intervals can be assigned slightly larger output quantities, and pulses corresponding to shorter time intervals can be assigned slightly smaller output quantities, but the sum of the output quantities of all pulses should still meet the target total output quantity for that statistical period. The aerosol output quantity corresponding to each smoke-generating pulse can be determined by the opening duration of the electromagnetic pulse valve, the allowable aerosol flow rate, or a pre-calibrated single release quantity. The specific control quantity used can be determined based on the structure of the aerosol generator. Different time interval arrangements can be used between different statistical periods. For example, the first statistical period uses the first predetermined code, and the second statistical period uses the second predetermined code. As long as the average aerosol output rate of each statistical period is within the preset rate deviation range, the phase distribution of the pulses can be continuously changed while maintaining the overall smoke supply level. It is understood that this example does not require the aerosol output of each smoke-generating pulse to be exactly the same, but rather that the total aerosol output over each statistical period should be adapted to the target smoke addition rate. Therefore, even if the pulse interval changes according to the code, the average smoke addition rate can be prevented from changing synchronously with the pulse density.

[0039] In some examples, determining the degree of time correlation between the state change of the smoke detector under test and the predetermined pulse coding sequence includes: Based on the output time of each smoke-generating pulse and the transport delay of aerosol from the aerosol generating device to the location of the smoke detector under test, the pulse arrival time corresponding to the location of the smoke detector under test for each smoke-generating pulse is determined. The number of times the state change time falls within different pulse arrival time periods is counted, and the phase distribution of the state change time relative to the corresponding smoke-generating pulse is determined. The degree of time correlation is determined based on the degree of deviation of the phase distribution from the uniform distribution. When the state change time is concentrated in a preset phase range of the smoke-producing pulse and the degree of time correlation reaches a preset correlation threshold, the degree of time correlation is determined to meet the preset correlation condition.

[0040] For example, the actual output time of each smoke-generating pulse can be recorded. The actual output time can be determined based on the control signal of the electromagnetic pulse valve; if there is a stable mechanical action delay after the valve receives the control signal, this delay can also be included in the actual output time. Then, the transport delay of the aerosol from the generating device to the detector location is determined. The transport delay can be obtained through pre-calibration. For example, a single low-dose aerosol pulse is input into the test chamber, and the change in smoke density caused by the pulse at the location of the detector under test is detected. The delay is determined by the difference between the aerosol output time and the time when the smoke density begins to change. For different wind speeds or different transport states, the corresponding transport delay can be determined separately. As long as the wind speed in the re-detection is within the preset deviation range, the transport delay or delay range under the corresponding conditions can be used. Assuming that a smoke-generating pulse is output at the tenth second, the transport delay is 1.2 seconds, and the effective duration of the pulse at the detector location is 0.6 seconds, then the period from the 11.2th second to the 11.8th second can be determined as the pulse arrival period corresponding to the smoke-generating pulse. For each state change time, it is determined whether it falls within a certain pulse arrival period. If a state change occurs within multiple overlapping arrival periods, it can be assigned to the corresponding smoke-producing pulse based on time distance, expected peak position, or predetermined assignment rules. To avoid this, the shortest time interval can be set when configuring pulse coding to reduce the likelihood of overlapping adjacent arrival periods. After determining the pulse arrival period to which the state change occurs, the relative position of the state change within that arrival period is calculated. For example, if a pulse arrival period lasts 600 milliseconds and the state change occurs 150 milliseconds after the start of that period, its phase is located at the beginning of that arrival period. The pulse arrival period can be divided into several phase ranges, and the number of state changes falling into each phase range can be counted. If the number of state changes in each phase range is roughly equal, the phase distribution is close to a uniform distribution; if a large number of state changes are concentrated in one or a few phase ranges, the phase distribution deviates significantly from a uniform distribution. The degree of temporal correlation can be determined by the proportion of phase concentration, the difference between the actual distribution and the uniform distribution, or other statistics that can characterize the degree of phase concentration. The preset correlation threshold can be determined based on experimental data under non-periodic aliasing conditions, statistical data from similar detectors, or pre-set judgment requirements. The preset phase range can be set within the expected effective response range after the aerosol pulse arrives. For example, if the detector state change usually requires a brief smoke intake and internal judgment after the pulse arrives, the preset phase range can avoid the initial moment of arrival and cover the subsequent time range that has practical response significance.

[0041] In some examples, altering the predetermined pulse coding sequence or applying a phase perturbation to the output time of the smoke-generating pulse includes: Select a candidate pulse coding sequence from multiple candidate pulse coding sequences that has a different time interval arrangement relationship with the currently used predetermined pulse coding sequence; or, While keeping the number of smoke-generating pulses and the total aerosol output constant within a preset statistical period, different time offsets are applied to the output times of at least some of the smoke-generating pulses within the preset statistical period. Re-detection is performed using the selected candidate pulse coding sequence or the smoke-producing pulse sequence after applying the time offset.

[0042] For example, multiple candidate pulse coding sequences can be pre-established. Each candidate sequence can use the same set of preset time intervals, but in a different order; alternatively, different time interval values ​​can be used, as long as they meet the actuation capability of the electromagnetic pulse valve and the smoke addition requirements of the test chamber. For instance, the current pulse coding sequence has time intervals of 0.8 seconds, 1.2 seconds, 1.6 seconds, 0.9 seconds, and 1.4 seconds. During re-detection, candidate sequences with time intervals of 1.4 seconds, 0.8 seconds, 1.2 seconds, 0.9 seconds, and 1.6 seconds can be selected. Although both use the same time intervals, the cumulative pulse output times differ. When selecting candidate sequences, it is important to avoid new sequences that are simply repetitions of the current sequence. The position of each time interval in the sequence, the adjacency of long and short intervals, and the cumulative output times of each pulse can be compared to select candidate sequences that cause a significant change in the pulse arrival phase. When using a phase perturbation method, first determine the planned output time of each pulse in the original pulse sequence, and then set a time offset for at least some pulses. For example, the second pulse can be delayed by 80 milliseconds, the third pulse advanced by 120 milliseconds, and the fifth pulse delayed by 160 milliseconds, while keeping the other pulses at their original output times. After applying the time offset, it should be checked whether there is still a sufficient execution interval between adjacent pulses and whether all pulses are still within the corresponding preset statistical period. If a pulse is advanced or delayed beyond the statistical period, or is too close to an adjacent pulse, the time offset can be reallocated. Keeping the output of each pulse constant, the total aerosol output within the statistical period remains unchanged as long as the number of pulses remains constant. If some pulses need to change their on-time due to the device's execution characteristics, the output of other pulses should be adjusted so that the total output within the statistical period remains the same as before the perturbation. After completing the candidate code selection or phase perturbation, re-detection is performed according to the new pulse sequence. The actual output time of each smoke-producing pulse, the detector state change time, the alarm time, and the alarm smoke density are re-recorded, and the time correlation is determined again. If the state changes in the re-detection are no longer concentrated within the original preset phase range, and the time correlation drops below the preset correlation threshold, it indicates that the significant correlation in the original detection may have been caused by a specific pulse time structure. If the re-detection still meets the preset relevant conditions, the candidate code can be changed or another set of phase perturbations can be used.

[0043] In some cases, considering that the aerosol generator continuously supplies aerosol to the fire detector test chamber during routine testing, relying solely on the smoke concentration measured at a single moment can typically only determine the overall optical attenuation caused by aerosols at that current spatial location. It cannot distinguish whether the aerosol at that location is primarily composed of newly generated aerosols that have just entered the test chamber, or primarily composed of aerosols that have already circulated multiple times within the test chamber. Therefore, some examples also include: In the continuous aerosol output by the aerosol generator, low-dose aerosol marker pulses with predetermined time codes are inserted at predetermined time intervals; Smoke concentration change information was collected at at least two smoke detection locations set along the aerosol flow direction inside the fire detector test chamber. The aerosol marker pulses are identified from the smoke concentration change information collected at each of the smoke detection locations to determine the arrival time, peak value, pulse width, and attenuation degree of the aerosol marker pulses at each of the smoke detection locations.

[0044] In some examples, it also includes: Based on the differences in arrival time, pulse width variation, peak attenuation, and residual degree of the aerosol marker pulses at different smoke detection locations, as well as the residual degree after multiple cycles in the fire detector test chamber, the residence time distribution and aging degree of the aerosols in the fire detector test chamber are determined. Based on the residence time distribution and the degree of aging, the aerosol output of the aerosol generating device and the ratio between the newly generated aerosol and the circulating aerosol in the fire detector test chamber are adjusted so that the smoke density and aerosol aging degree of the smoke detector under test are within the corresponding preset ranges.

[0045] Understandably, to obtain aerosol timing information, this scheme inserts low-dose aerosol marker pulses into the continuous aerosol output. A marker pulse refers to a short-duration, identifiable aerosol concentration change based on the continuous aerosol baseline output. Since the output time, duration, and time code of this concentration change are predetermined, it can be considered a time marker in the aerosol transport process. "Low dose" means that the amount of aerosol added by the marker pulse should be sufficient to be identified by the smoke detection location, but insufficient to significantly alter the normal smoke reception process of the fire detector. For example, the marker pulse can create an identifiable local spike on the continuous aerosol concentration change curve without causing the overall smoke density in the test chamber to suddenly exceed the alarm threshold of the tested detector. This balances the detectability of the marker pulse with the stability of the test conditions. The predetermined time code is used to distinguish between different marker pulses and different cyclic echoes of the marker pulses. If all marker pulses use the exact same fixed interval, when multiple cycles occur within the test chamber, the residual change formed after one cycle of the previous marker pulse may overlap with the first arrival of the next marker pulse, making it impossible to determine which marker pulse a certain concentration change originated from. By employing predetermined time encoding, a pre-defined and identifiable time interval arrangement can be established between adjacent marker pulses, allowing for the identification of each marker pulse using a complete time structure. For example, several consecutive marker pulses can be spaced at different intervals. When the same interval arrangement appears at a downstream detection position, even if the marker pulses have broadened and attenuated, their origin can be identified based on the relative time relationship between multiple pulses.

[0046] For example, the aerosol generator can first output continuous aerosol according to the target smoke supply rate detected by the fire detector. During continuous output, the aerosol generator is controlled to briefly increase the aerosol output at predetermined time intervals, thereby forming low-dose marker pulses. The formation of marker pulses can be achieved by briefly increasing the aerosol generation, briefly extending the aerosol output duration, or briefly changing the supply of aerosol into the test chamber. Regardless of the method used, the planned output time and actual output time of each marker pulse should be recorded. If there is a delay between the aerosol generator receiving the control command and the actual aerosol formation, the actual output time can be corrected according to a pre-calibrated device response time. The predetermined time code can consist of several not entirely identical time intervals. For example, after the first marker pulse is output, the second marker pulse is output after four seconds, the third marker pulse after seven seconds, and the fourth marker pulse after five seconds. The arrangement of the time intervals consisting of four seconds, seven seconds, and five seconds forms an identifiable time code. In other embodiments, different marker pulses can also use different pulse durations. For example, in a coding unit, the first marker pulse lasts for a short time, the second marker pulse lasts for a longer time, and the third marker pulse returns to a shorter time. During identification, both the time interval between pulses and the duration of each pulse can be utilized simultaneously. However, regardless of the coding method used, the additional aerosol amount of the marker pulses should be limited to avoid the marking behavior itself significantly altering the smoke density and aerosol composition at the detector under test. The time interval of the marker pulses should also be determined in conjunction with the time required for the aerosol to complete one cycle within the test chamber. If the time interval is too short, adjacent marker pulses may overlap during propagation; if the time interval is too long, less marker data can be obtained per unit detection time. Therefore, an appropriate coding interval can be determined based on the pre-measured aerosol cycle time, pulse broadening range, and sampling frequency at the detection location.

[0047] For example, at least two smoke detection locations are sequentially set along the aerosol flow direction within the test chamber. The first smoke detection location can be set before the aerosol enters the area where the detector under test is located, and the second smoke detection location can be set after the aerosol flows through the area where the detector under test is located. Smoke concentration change information is collected at each detection location according to a unified time reference. A unified time reference is crucial because the difference in arrival time between different locations may be only a short time. If different and uncorrected timing references are used at each detection location, timing errors will be incorrectly interpreted as aerosol transport delays. The sampling frequency at each detection location should be sufficient to distinguish the rise, peak, and fall of the labeled pulse. If the labeled pulse is expected to last for several seconds, the sampling frequency should be able to obtain multiple concentration sampling points within that duration. This allows for a more accurate determination of the arrival time, peak value, and pulse width. Smoke concentration change information may include continuously collected smoke density values, optical attenuation values, or detection values ​​that reflect local aerosol concentration changes. To identify low-dose labeled pulses superimposed on a continuous aerosol background, the trend of change in the continuous background over a short time range can be determined first, and then the local increment relative to this background trend can be extracted from the actual concentration change. For example, when the overall smoke density in the test chamber is slowly increasing, the marker pulse appears as a short-lived spike superimposed on the upward trend. In this case, it is not appropriate to directly regard the absolute concentration of this spike as the entire marker pulse. Instead, the background concentration that could be reached during this period without the marker pulse should be determined, and the marker pulse should be described as the increment of the actual concentration relative to the background concentration.

[0048] For example, a matching local change sequence can be searched for in the concentration change information at each detection location based on a predetermined time code. During identification, a certain deviation between the actual pulse interval and the predetermined code can be allowed to accommodate time variations caused by aerosol transport, detection sampling, and pulse broadening. For each identified marker pulse, the arrival time can be determined as the moment when the concentration begins to rise continuously relative to the local background concentration. To avoid false identification triggered by a single noisy sampling point, arrival can be confirmed only after the concentration increment continuously reaches the corresponding judgment condition. The peak value can be determined as the maximum increment relative to the background concentration within the duration of the marker pulse. If short-term abnormal spikes exist in the sampling data, their significance for actual aerosol propagation can be confirmed based on consecutive sampling values ​​before and after the marker pulse. The pulse width can be determined based on the duration between a significant rise and a significant recovery of the marker pulse, or based on the duration corresponding to a certain concentration range near the peak. Regardless of the determination method, consistent judgment rules should be used for each detection location and each detection to compare pulse width changes. The attenuation degree can be determined based on the peak value change of the same marker pulse at upstream and downstream detection locations, or in combination with the overall concentration increment change after pulse broadening. When comparing only peak values, it's important to note that a decrease in peak value may simply be due to pulse broadening and doesn't necessarily indicate significant aerosol loss. Therefore, peak attenuation can be analyzed in conjunction with pulse width changes: if the peak value decreases while the pulse broadens significantly, it likely indicates that aerosols have been dispersed over a longer arrival time range; if the peak value decreases and the overall identifiable pulse is also significantly weakened, it more likely indicates increased deposition or other losses. For cyclic test chambers, subsequent residual signals matching the same time code can be searched after the initial arrival. The time interval between subsequent signals and the initial signal corresponds to the time required for the aerosol to complete one cycle within the test chamber.

[0049] For example, the first appearance of the labeled pulse at the first detection location can be used as a reference to determine its first arrival time at the second detection location. The time difference between the two reflects the transport time of the main aerosol portion within the corresponding segment. Subsequently, the dispersion range of aerosol arrival times is determined based on the start time, peak time, end time, and tailing of the labeled pulse at the second detection location. The larger the pulse width, the greater the difference in residence time between different portions of the labeled aerosol. For test chambers capable of recognizing multiple-cycle signals, subsequent responses encoded at the same time can be searched in the concentration change information. The time difference between two adjacent responses can be used to determine the main cycle time. The residual level after the first cycle, the residual level after the second cycle, and the residual level in subsequent cycles can be used to determine the relative proportion of long-residence-time aerosols. For example, if a labeled pulse first arrives at a downstream location and still shows a significant encoded response after one cycle time, and a weaker response after the second cycle time, this indicates that a portion of the labeled aerosol has completed at least one cycle, while a smaller portion continues to remain until the second cycle. When determining the residence time distribution, the directly arriving portion, the delayed arriving portion, and the residual portion after multiple cycles can be categorized into different residence time ranges. The goal is not necessarily to obtain the precise residence time of each particle, but rather to distinguish whether the current aerosol in the test chamber is mainly composed of short-term residence components or contains a higher proportion of long-term residence components. To improve the stability of the assessment, residence time information can be repeatedly obtained using multiple marker encoding units. If multiple consecutive marker pulses exhibit similar first arrival times, broadening patterns, and cycle residual patterns, the residence time distribution in the current test chamber can be considered relatively stable. Significant differences between different marker pulses indicate that the current flow or mixing state may be changing.

[0050] For example, propagation parameters of the labeled pulses can be summarized according to a predetermined statistical period, including differences in arrival time between different locations, pulse width variations, peak attenuation, and residual levels after each cycle. When the residence time is short, the initial response is concentrated, and the cycle residual is low, the aerosol aging degree can be determined as low. When the pulse broadens significantly, the tail increases, and the residual after multiple cycles is strong, the aerosol aging degree can be determined as high. When determining the aging degree, it is not advisable to use only a single peak attenuation parameter, as peak attenuation may be affected by diffusion, mixing, and deposition simultaneously. A more reliable judgment can be obtained by analyzing peak attenuation together with pulse broadening and residual after multiple cycles. For example, although the peak value decreases, the pulse broadens significantly and retains a strong response after one cycle, indicating that the labeled aerosol does not primarily disappear but is dispersed and continuously retained within the chamber. In this case, the long-residence component may increase, and the aging degree may rise. Conversely, if the peak value decreases, the pulse does not broaden significantly, and the residual after subsequent cycles is also weak, it indicates that the labeled aerosol may be deposited or expelled relatively quickly. Although aerosol loss is significant at this point, the accumulation of old aerosols inside the chamber may not be very high. Therefore, it is necessary to consider the residence time distribution, rather than simply equating high attenuation with high aging. The degree of aging can be expressed using multiple levels or continuously varying values. Regardless of the method used, the judgment rules should be adapted to the corresponding type of aerosol, the test chamber structure, and the testing conditions.

[0051] For example, the system can pre-set the target smoke density range and target aerosol aging degree range corresponding to the current detection item. During the detection process, the current smoke density status is determined based on the smoke concentration change information, and the current residence time distribution and aging degree are determined based on the propagation and residue of the marker pulse. When the smoke density is lower than the corresponding preset range and the aerosol aging degree is also low, the output of new aerosols from the aerosol generator can be appropriately increased. The increased new aerosols not only increase the smoke density but also increase the proportion of newly generated aerosols in the total aerosols. When the smoke density is within the preset range but the aerosol aging degree is high, it is not advisable to simply continue to increase the total smoke volume, otherwise the smoke density may exceed the preset range. In this case, the ratio between newly generated aerosols and circulating aerosols should be changed. For example, the degree to which aged circulating aerosols continue to participate in the detection can be reduced, and the corresponding aerosol volume can be supplemented by newly generated aerosols, so that the smoke density is maintained near the original range while reducing the overall aging degree. When the smoke density is higher than the preset range and the aerosol aging degree is also high, the output of the aerosol generator can be reduced, and the proportion of long-term circulating aerosols can be decreased. This avoids further increasing the smoke density and reduces the continuous accumulation of aerosols that have been circulating for a long time. When the smoke density is lower than the preset range but the aging degree is close to the upper limit, the smoke density should be increased by increasing the relative proportion of newly generated aerosols, rather than relying mainly on retaining old circulating aerosols to increase the smoke density. Otherwise, even if the smoke density reaches the target range, the aerosol aging degree may exceed the allowable range. After adjustment, subsequent low-dose labeled pulses can be inserted to redetermine the residence time distribution and aging degree. Only when the smoke density and aging degree corresponding to the detector under test are both within the corresponding preset ranges is the time period considered as meeting the aerosol conditions. Being within the corresponding preset ranges does not mean that the two parameters are independent of each other. Changes in the aerosol output may simultaneously affect the smoke density and the ratio of new to old aerosols, and changes in the ratio of new to old aerosols may also affect the smoke density. Therefore, in actual adjustment, it is necessary to determine the adjustment direction and magnitude based on the current state of the two parameters, and to reconfirm the two parameters after adjustment.

[0052] In some cases, smoke detectors typically have smoke inlets, guide ribs, labyrinth structures, light-shielding structures, and internal smoke-sensing chambers. These structures are not necessarily perfectly symmetrical circumferentially. Even if the detector housing is approximately circular, aerosols entering from different directions may still enter the smoke-sensing chamber along different paths, resulting in different alarm smoke concentrations and response times. However, in a ring-shaped test chamber, the differences detected during forward and reverse flow are not necessarily entirely attributable to the detector itself. The curved sections of the test chamber, the fan position, rectifier components, the aerosol generator connection location, the chamber connection structure, and local cross-sectional changes can also cause systematic differences in smoke distribution upstream and downstream of the detector in a given flow direction. If detection is only performed in one flow direction, it is impossible to determine whether the detector response deviation is caused by the detector's smoke inlet structure or by the smoke distribution deviation formed by the ring-shaped test chamber in that flow direction. Based on this, some examples also include: While keeping the installation position and posture of the smoke detector under test unchanged, the airflow in the annular test chamber is controlled to flow along a first flow direction and a second flow direction opposite to the first flow direction, and the same smoke generation parameters are used for the detection process in the two flow directions respectively. By using optical smoke densitometers installed on both sides of the smoke detector under test, the smoke concentration change information of the upstream and downstream sides of the smoke detector under test in two flow directions is collected respectively, and the alarm smoke concentration and response time of the smoke detector under test in two flow directions are also collected. Based on the difference in smoke concentration changes on the upstream and downstream sides under two flow directions, the directional deviation of the annular test chamber on the smoke distribution is determined. Based on the difference in alarm smoke concentration and response time after eliminating the directional deviation, the sensitivity of the smoke inlet structure of the smoke detector under test to the airflow direction is determined.

[0053] For example, the smoke detector under test is fixed at a predetermined detection position in an annular test chamber, maintaining its installation height, orientation, and circumferential direction. A first optical smoke densitometer is positioned on one side of the detector, and a second optical smoke densitometer is positioned on the other side. The relative positions of the two optical smoke densitometers and the detector remain unchanged during both detection processes. During the first detection process, the airflow within the annular test chamber flows in a first flow direction. The optical smoke densitometer that first contacts the aerosol is designated as the upstream optical smoke densitometer, and the other optical smoke densitometer that the aerosol contacts after passing through the detector's area is designated as the downstream optical smoke densitometer. The aerosol generator outputs aerosol according to predetermined smoke generation parameters, continuously collecting smoke concentration changes on both the upstream and downstream sides, and recording the detector's state changes. When the detector enters an alarm state, the corresponding alarm smoke concentration and response time are recorded. During the second detection process, without changing the detector's position and orientation, the airflow flows in a second flow direction opposite to the first flow direction. The original downstream optical smoke density meter becomes the upstream optical smoke density meter, and the original upstream optical smoke density meter becomes the downstream optical smoke density meter. The second detection process uses the same smoke generation parameters as the first detection process to reduce the impact of differences in aerosol generation conditions on the comparison results. The changes in smoke concentration over time on the upstream and downstream sides are compared under both flow directions. The comparison can include the moment aerosols begin to arrive, the rate of concentration increase, the time required to reach the same concentration, the concentration difference between the upstream and downstream sides, and the deviation after the concentration stabilizes. If, under the first flow direction, the smoke concentration on the upstream side is consistently higher than that on the downstream side, and under the second flow direction, the optical smoke density meter at a fixed spatial location within the chamber still measures a higher concentration, then the difference may mainly originate from the local structure of the chamber or uneven smoke distribution across the detection cross-section. If the concentration difference changes with the upstream and downstream sides—that is, regardless of the airflow direction, the upstream side detects aerosols earlier while the downstream side experiences a corresponding delay—then this difference mainly reflects the normal transport process of aerosols through the section where the detector is located. After determining the directional deviation caused by the test chamber, the alarm smoke concentration and response time of the detector in the two directions are compared. The smoke concentration and aerosol arrival time corresponding to the detector alarm can be corrected based on the directional differences recorded by the optical smoke densitometer. The remaining response differences after correction can be used to characterize the sensitivity of the detector's smoke inlet structure to the airflow direction. To improve the stability of the results, the detection can be repeated in the order of the first flow direction, the second flow direction, and then back to the first flow direction. The results obtained again along the first flow direction can be used to determine whether the aerosol generation conditions and detector state within the test chamber have continuously changed. If the two detection results in the first flow direction are similar, while the results in the second flow direction remain consistently different, the judgment of directional sensitivity has higher reliability.

[0054] In some cases, considering that after long-term aerosol testing in a ring-shaped test chamber, some aerosols may deposit or adsorb onto the chamber walls, pipe inner walls, joint gaps, fan blades, and other internal structural surfaces. After the aerosol generator output is stopped, these aerosols already attached to the walls do not necessarily remain stationary. When the airflow velocity inside the chamber changes, the shear force near the walls changes. Particles that were not initially firmly attached may re-enter the airflow. When the temperature changes, the temperature difference between the walls and the airflow, the particle surface condition, and the adhesion conditions may also change, causing some of the aerosols stored on the walls to be released. Therefore, if the smoke concentration rises again after a change in wind speed or temperature without new aerosol input, this rise cannot be interpreted as the aerosol generator producing new smoke; rather, the effect of smoke release from the walls should be considered. Based on this, some examples also include: Before the formal test, stop the aerosol generator from outputting aerosols, and while keeping the aerosol output stopped, change the wind speed and temperature inside the annular test chamber according to a predetermined adjustment sequence. Smoke concentration decay curves and smoke concentration recovery curves were collected at each wind speed adjustment stage and each temperature adjustment stage. The smoke storage capacity of the wall of the annular test chamber was determined based on the smoke concentration recovery amount when no new aerosols were introduced. The release characteristics of the aerosols stored on the wall were determined based on the difference in smoke concentration recovery rate at different wind speeds. If the amount of smoke stored on the wall exceeds the preset smoke storage limit, the annular test chamber is subjected to a purging treatment adapted to the release characteristics, and the contribution of the aerosols released from the wall to the smoke concentration at the test location is determined according to the release characteristics during the formal testing process.

[0055] For example, after completing one smoke generation test, the aerosol generator output is stopped, preventing further aerosol input into the annular test chamber. The optical smoke densitometer is kept running continuously, recording the smoke concentration decay process after smoke generation stops. In the first wind speed adjustment phase, the airflow inside the chamber is maintained at a low wind speed, and the smoke concentration decreases over time. Once the concentration decrease trend reaches a relatively stable state, the wind speed inside the chamber is increased, and the smoke concentration change continues to be recorded. If the smoke concentration changes from a decreasing state to a short-term increase after increasing the wind speed, or if the decreasing rate slows significantly, it can be considered that the higher wind speed causes some of the smoke stored on the wall to re-enter the airflow. The deviation of this concentration rebound from the predicted decay trend before wind speed adjustment can be used to characterize the amount of wall release caused by this wind speed change. Higher wind speeds can also be set. If the concentration rebounds significantly when the wind speed is increased for the first time, and rebounds again when the wind speed is increased for the second time, it indicates that there are aerosols with different degrees of adhesion stability on the wall. Lower wind speeds can release the weaker adhered parts, while higher wind speeds can further release the more firmly adhered parts. Temperature adjustment can be performed before or after the corresponding wind speed stage. During adjustment, the aerosol generator remains off-peak, and the smoke concentration before and after the temperature change is recorded. If a concentration rebound occurs after heating or cooling that cannot be explained by the original decay trend, it can be determined that the temperature change triggered the release of smoke stored on the wall. To distinguish between the effects of wind speed and temperature, stages that only change wind speed and stages that only change temperature can be set separately. For example, first keep the temperature constant and gradually change the wind speed; then fix the wind speed and change the temperature. This allows obtaining the responses of smoke stored on the wall to wind speed and temperature changes respectively. The amount of smoke stored on the wall can be determined based on the concentration rebound that occurs when no new aerosol input is present. This concentration rebound can be expressed as the increase in the peak concentration relative to the original decay curve, or as the increase in the overall concentration change during the rebound period. If the rebound duration is long, using only the instantaneous peak value may underestimate the impact of wall release; therefore, the rebound amplitude and duration should be considered together. The release characteristics at different wind speeds can be determined based on the wind speed at which the concentration begins to rise, the rate of rise, the time required to reach the peak, and the concentration decrease after the wind speed recovers. If a small change in wind speed can cause a rapid rise, it indicates low stability of the smoke deposits on the wall, and fluctuations in the normal wind speed during formal testing may also cause interference. If a rise only occurs at higher wind speeds, it indicates that the smoke deposits on the wall are relatively stable at the normal testing wind speed, but may still be released when switching testing conditions. When it is determined that the amount of smoke deposited on the wall exceeds the preset smoke storage limit, purging can be performed based on the release characteristics. If the smoke deposits on the wall are mainly released at high wind speeds, a higher wind speed adapted to the release characteristics can be used for purging; if temperature changes significantly promote release, purging can be combined with purging under the corresponding temperature conditions. After purging, testing should be performed again according to the same wind speed and temperature adjustment sequence. If no significant concentration rise occurs, it indicates that the influence of the smoke deposits on the wall has been reduced.During the formal testing process, if the current wind speed and temperature changes match the identified wall release conditions, the contribution of wall-released aerosols to the smoke concentration at the detection location can be determined based on the corresponding release characteristics, thus avoiding attributing all changes in smoke concentration to the aerosol generator output.

[0056] In some cases, optical smoke densitometers determine smoke concentration by measuring the attenuation of light as it passes through the detection area. When exposed to aerosol-containing test environments for extended periods, particles may adhere to the smoke densitometer's emission, receiving, or protective windows. Window contamination can also cause reduced transmitted light, which may be mistakenly interpreted as an increase in aerosol concentration within the test chamber. Simply observing the smoke densitometer readings makes it difficult to distinguish whether the light attenuation originates from suspended aerosols in the optical path or from deposited particles on the optical window. Conventional methods often require stopping the test and manually cleaning the window, making it impossible to directly determine the degree of window contamination while the aerosol concentration remains stable. Therefore, in some examples, the following methods are also included: When the aerosol concentration inside the annular test chamber is in a preset stable state, the main circulating airflow state inside the annular test chamber remains unchanged, and the local cleaning air curtain that delivers clean gas toward the optical window of the optical smoke density meter is alternately opened and closed. The measurement values ​​of the optical smoke density meter are collected before the local cleaning air curtain is opened, during the opening, and after the opening. The measurement values ​​of the reference optical smoke density meter set outside the effective range of the local cleaning air curtain are also collected simultaneously. Based on the recovery amount of the optical smoke density meter's measurement value as the local cleaning air curtain is opened, and the change in the measurement value of the reference optical smoke density meter within the corresponding time period, the measurement attenuation caused by the optical window contamination is determined, and the measurement attenuation is used to distinguish between the actual concentration change of aerosols in the annular test chamber and the apparent concentration change caused by the optical window contamination.

[0057] For example, the aerosol concentration inside the annular test chamber is brought to a preset stable state while maintaining the main circulating airflow. An optical smoke densitometer for which the degree of window contamination is to be determined is selected, and a local clean air curtain output position is set near its optical window. A reference optical smoke densitometer is positioned outside the clean air curtain's effective range, allowing it to measure aerosol changes in the same test section without being directly affected by the clean gas. When the local clean air curtain is closed, the measurements of both optical smoke densitometers are recorded simultaneously to obtain the baseline state before the clean air curtain is opened. Subsequently, the local clean air curtain is opened, and the two measurements are recorded simultaneously again. If the measurement value of the optical smoke densitometer under test recovers after the clean air curtain is opened, while the measurement value of the reference optical smoke densitometer remains essentially unchanged, it indicates that the window contamination of the optical smoke densitometer under test has been partially removed or the deposition effect near the window has weakened. If the measurements of both optical smoke densitometers change similarly within the same time period, this change is more likely due to actual aerosol concentration fluctuations inside the annular test chamber, and cannot be entirely attributed to the effect of the local clean air curtain on window contamination. After the clean air curtain is opened for a period of time, it is closed, and measurements from two optical smoke densitometers are continuously collected. If the optical smoke densitometer under test remains in its recovered state after closure, it indicates that the clean air curtain may have removed contaminants already attached to the window. If the measurement gradually returns to its original state after closure, while the reference optical smoke densitometer shows no corresponding change, it indicates that there is still a strong tendency for re-deposition near the window. The measurement attenuation caused by window contamination can be determined based on the recovery amount of the optical smoke densitometer under test before and after the clean air curtain is opened, and corrected using the change in the reference optical smoke densitometer over the same period. For example, if the optical smoke densitometer under test shows a large reduction in light attenuation, while the reference optical smoke densitometer shows only a small change in aerosol concentration, the difference between the two can be used to characterize the contribution of window contamination. The local clean air curtain can be opened and closed alternately multiple times. If measurement recovery occurs in the same direction and with similar amplitude after each opening, it indicates that the change is repeatable. If only one abnormal change occurs, it is necessary to combine the corresponding data from the reference optical smoke densitometer to determine whether it is an accidental aerosol fluctuation. Once the measurement attenuation caused by window contamination is determined, the actual aerosol concentration change can be distinguished from the apparent concentration change caused by window contamination during formal data processing. If the window contamination exceeds the allowable range, the window can be cleaned, and the measurement status can be reconfirmed after cleaning.

[0058] In some cases, considering that some smoke detectors may actually activate their alarm actuators after entering an alarm state, for example, audible components may vibrate, indicator components may operate periodically, mechanical components may actuate, and changes in circuit power consumption may cause temperature variations near the detector housing. These actions may disturb the local airflow around the detector and alter the transport state of aerosols near the smoke inlet. If the alarm actuator vibrates, particles adhering to the detector housing or near the smoke inlet may be resuspended; if the actuator's action causes local air movement, aerosols may be drawn in, expelled, or redistributed. The change in the detector's output state after an alarm may not fully reflect the continuous response of the smoke detection circuit to aerosols and may also be affected by the actions of the alarm actuator itself, which in turn alter local smoke conditions. Based on this, some examples also include: The same smoke generation parameters, wind speed parameters, and temperature parameters are used to perform the first detection process and the second detection process respectively. In the first detection process, the alarm execution component of the smoke detector under test is allowed to act in response to the alarm state. In the second detection process, the action of the alarm execution component is suppressed without changing the operation of the smoke detection circuit of the smoke detector under test. Information on local wind speed changes around the smoke detector under test, smoke concentration changes on the upstream and downstream sides, and the status output of the smoke detector under test are collected during the two detection processes respectively. Based on the differences between the local wind speed change information and the smoke concentration change information during the two detection processes, the disturbance amount caused by the alarm execution component's action to the airflow and smoke distribution around the smoke detector under test is determined, and the status output evaluation result of the smoke detector under test after the alarm is corrected based on the disturbance amount.

[0059] For example, in the first detection process, the aerosol generator outputs aerosols according to predetermined smoke production parameters, and the wind speed and temperature inside the annular test chamber are maintained under predetermined conditions. The smoke detector under test operates normally, and when the smoke detection circuit determines that the alarm conditions have been met, the alarm execution component is allowed to operate normally. Local wind speed change information is collected around the detector, and smoke concentration change information is collected by detection devices located upstream and downstream of the detector. Simultaneously, the state output of the detector before and after entering the alarm state is recorded. The second detection process uses the same smoke production parameters, wind speed parameters, and temperature parameters. The smoke detection circuit of the detector under test still receives and processes the smoke signal normally and generates an alarm state judgment normally, but the actual actions of the alarm execution component that would affect the surrounding environment are suppressed. Here, the action of the alarm execution component is suppressed, not the detector exiting the smoke detection state. Otherwise, it cannot be confirmed whether the state output in the second detection process corresponds to the same smoke judgment process as the first detection process. When comparing the two detection processes, the moment when the detector enters the alarm state can be used as an alignment benchmark to compare the local wind speed changes before and after the alarm. If the local wind speeds are similar before the alarm in both detection processes, and the first detection process experiences periodic wind speed fluctuations after the alarm actuator activates, while the second detection process does not exhibit corresponding fluctuations, then the wind speed difference can be attributed to the activation of the alarm actuator. Subsequently, the changes in smoke concentration on the upstream and downstream sides are compared. If the first detection process experiences a local concentration decrease, concentration oscillation, or short-term concentration increase after the alarm actuator activates, while the second detection process does not exhibit the same change, it can be further determined that the actuator activation altered the aerosol distribution near the detector. The disturbance amount can be determined based on the differences in local wind speed and smoke concentration between the two detection processes after the alarm. If the alarm actuator activation causes periodic fluctuations in downstream concentration, these periodic fluctuations can be separated from the post-alarm status output evaluation. When evaluating the status output, the focus should be on analyzing whether the alarm status is stable, whether there are repeated exits and re-entries into the alarm state after the alarm, whether the status output recovery time is abnormal, and whether the output fluctuates during continuous alarm periods. If the above changes correspond to changes in local airflow or smoke concentration caused by the actuator, the judgment on the stability of the smoke detection circuit should be revised. To avoid differences in residual smoke between two tests, the test chamber can be restored to the same initial smoke conditions before each test. Alternatively, the execution order of the two test processes can be swapped to determine whether the results are affected by the order of the tests.

[0060] In some cases, even if two detections ultimately have the same aerosol concentration, wind speed, and temperature, the state of the detector may differ. This is because the detector and its surrounding aerosol system may retain previous environmental conditions. For example, increasing the temperature first and then the smoke concentration, versus increasing the smoke concentration first and then the temperature, will result in the same final temperature and smoke concentration, but the state of the detector's internal components, the smoke-sensing chamber, the housing surface, and the particles entering the smoke-sensing chamber may differ. When the temperature changes first, the detector's internal components may thermally adapt first, and subsequently entering aerosols will be detected under already stable temperature conditions. If the smoke concentration increases first, some particles may enter the smoke-sensing chamber before the internal temperature of the detector has stabilized and undergo deposition, volatilization, or optical changes differently than in another sequence. Similarly, increasing the wind speed first and then the smoke concentration will affect the initial velocity of aerosols entering the detector; increasing the smoke concentration first and then the wind speed may cause some aerosols to enter and remain in the smoke-sensing chamber under low wind speed conditions. Even if the final wind speed is the same, the quantity and distribution of existing aerosols inside the detector may still differ. Based on this, some examples also include: The aerosol concentration, wind speed, and temperature inside the annular test chamber are adjusted according to at least two different sequences of environmental parameter changes, so that each test process performed according to different sequences of environmental parameter changes has the same final aerosol concentration, final wind speed, and final temperature. Collect the status output of the smoke detector under test during each detection process, during the period of environmental parameter changes and after reaching the same final environmental parameters, and determine the alarm smoke concentration, response time, and status output recovery time corresponding to each detection process; The alarm smoke concentration, response time, and status output recovery time obtained under different environmental parameter change sequences are compared. Based on the comparison results, the sensitivity of the tested smoke detector to the history of environmental parameter changes is determined, and the environmental parameter change sequence that causes the largest performance deviation of the tested smoke detector is determined as the detection environmental parameter change sequence.

[0061] For example, common final aerosol concentration, final wind speed, and final temperature are determined for each detection process. The only difference between the different detection processes is the order in which these final parameters are achieved. In the first detection process, the temperature can be adjusted to the final temperature first, the wind speed adjusted after the temperature reaches the corresponding state, and finally the aerosol concentration increased. In the second detection process, the aerosol concentration can be increased first, then the wind speed adjusted, and finally the temperature adjusted. Other sequences of change can also be set, such as adjusting the wind speed first, then the temperature, and finally increasing the aerosol concentration; or increasing the aerosol concentration first, then adjusting the temperature, and finally adjusting the wind speed. The set sequence should correspond to the environmental changes that may occur during the actual detection process. In each detection process, the detector status output is collected from the moment the first environmental parameter is changed, and its output is continuously recorded during parameter changes, during the period when each parameter reaches the target value, and after all parameters reach the same final state. When the detector enters the alarm state, the corresponding alarm smoke concentration and response time are recorded. The starting reference for the response time should be consistent across different detection processes, for example, based on the moment when the aerosol begins to enter the detection zone. After the environmental parameters recover or the smoke concentration decreases, continue recording the detector's status output to determine the time required for it to recover from the alarm state to the non-alarm state. If the detector has different recovery times under different parameter change sequences, it indicates that the residual particles in the smoke-sensing chamber, the temperature adaptation process, or the state of the detection circuit have been affected by previous environmental changes. Compare the status outputs after reaching a common final parameter under different change sequences. If the final parameter is the same, but the detector maintains a higher smoke-sensing signal under one sequence and a lower smoke-sensing signal under another sequence, it can be determined that the detector has historical sensitivity to environmental parameter changes. Furthermore, the alarm smoke concentration, response time, and status output recovery time corresponding to each change sequence can be compared, and the change sequence with the largest deviation can be determined. This sequence can be used as the environmental parameter change sequence for testing, so that its performance can be evaluated under conditions that more easily expose the detector's historical sensitivity. To improve the reliability of the comparison, each change sequence can be repeated. Before each test, the detector and test chamber are restored to the same initial conditions to avoid the residue of the previous test becoming additional change history for the next test. The main source of sensitivity can also be determined by changing the order of two adjacent parameters. For example, under the same conditions, only the order of temperature regulation and smoke generation regulation can be swapped. If the test results change significantly, then the temperature change and the order in which aerosols enter can be considered the main influencing factors.

[0062] The above describes the smoke detector detection method in the embodiments of this application. The following describes the smoke detector detection system in the embodiments of this application.

[0063] Please see Figure 2 This application describes one embodiment of a smoke detector detection system 200, which may include: The conveying unit 201 is used to place the smoke detector under test in the fire detector test chamber and control the aerosol generator to convey aerosol into the fire detector test chamber. The aerosol generator outputs the aerosol with multiple smoke-generating pulses through an electromagnetic pulse valve. The adjustment unit 202 is used to change the time interval between adjacent smoke-generating pulses according to a predetermined pulse coding sequence, so that the plurality of smoke-generating pulses form a non-equal interval smoke-generating pulse sequence; The acquisition unit 203 is used to acquire the status output information of the smoke detector under test during the action of the non-equal interval smoke pulse sequence, and record the time of status change corresponding to the status output information; The determining unit 204 is used to determine the degree of time correlation between the state change of the smoke detector under test and the predetermined pulse coding sequence based on the output time of each smoke-generating pulse and the state change time. The analysis unit 205 is used to determine, when the time correlation reaches a preset correlation condition, that the current detection process is affected by the periodic aliasing between the smoke-generating pulse and the internal sampling period of the smoke detector under test, and to change the predetermined pulse coding sequence or apply a phase perturbation to the output time of the smoke-generating pulse in order to re-detect the smoke detector under test.

[0064] above Figure 2 The smoke detector detection system in this application embodiment has been described from the perspective of modular functional entities. The following section describes the smoke detector detection system in this application embodiment in detail from the perspective of hardware processing. Please refer to [link to relevant documentation]. Figure 3 One embodiment of the smoke detector detection system 300 in this application includes: The system includes an input device 301, an output device 302, a processor 303, and a memory 304, wherein the number of processors 303 can be one or more. Figure 3 Taking a processor 303 as an example. In some embodiments of this application, the input device 301, output device 302, processor 303, and memory 304 can be connected via a bus or other means, wherein... Figure 3 Taking the example of a connection between China and Israel via a bus.

[0065] Specifically, the processor 303 executes the above steps by calling the operation instructions stored in the memory 304.

[0066] By calling the operation instructions stored in memory 304, processor 303 is also used to execute... Figure 1 Any of the methods in the corresponding embodiments.

[0067] Please see Figure 4 , Figure 4 A schematic diagram illustrating an embodiment of the electronic device provided in this application.

[0068] like Figure 4 As shown, this application provides an electronic device 400, including a memory 304, a processor 303, and a computer program 411 stored in the memory 304 and executable on the processor 303. When the processor 303 executes the computer program 411, it implements the above steps.

[0069] In practical implementation, when processor 303 executes computer program 411, it can achieve... Figure 1 Any of the corresponding implementation methods in the embodiments.

[0070] Since the electronic device described in this embodiment is the device used to implement a smoke detector detection system in the embodiments of this application, those skilled in the art can understand the specific implementation method and various variations of the electronic device in this embodiment based on the method described in the embodiments of this application. Therefore, how the electronic device implements the method in the embodiments of this application will not be described in detail here. Any device used by those skilled in the art to implement the method in the embodiments of this application falls within the scope of protection of this application.

[0071] Please see Figure 5 , Figure 5 This is a schematic diagram illustrating an embodiment of a computer-readable storage medium provided in this application.

[0072] like Figure 5 As shown, this embodiment provides a computer-readable storage medium 500 on which a computer program 511 is stored, which implements the above steps when executed by a processor.

[0073] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for detecting smoke in a fire detector, characterized in that, include: The smoke detector under test is placed inside the fire detector test chamber. An aerosol generator is controlled to deliver aerosol into the fire detector test chamber. The aerosol generator outputs the aerosol with multiple smoke-generating pulses through an electromagnetic pulse valve. The time interval between adjacent smoke-generating pulses is changed according to a predetermined pulse coding sequence, so that the multiple smoke-generating pulses form a non-equal interval smoke-generating pulse sequence. During the non-equal interval smoke-generating pulse sequence, the status output information of the smoke detector under test is collected, and the time of status change corresponding to the status output information is recorded. Based on the output time of each smoke-generating pulse and the time of the state change, determine the degree of time correlation between the state change of the smoke detector under test and the predetermined pulse coding sequence; If the time correlation reaches the preset correlation condition, it is determined that the current detection process is affected by the periodic aliasing between the smoke-generating pulse and the internal sampling period of the smoke detector under test. The predetermined pulse coding sequence is changed or a phase perturbation is applied to the output time of the smoke-generating pulse to re-detect the smoke detector under test. Determining the time correlation between the state change of the smoke detector under test and the predetermined pulse coding sequence includes: Based on the output time of each smoke-generating pulse and the transport delay of aerosol from the aerosol generating device to the location of the smoke detector under test, the pulse arrival time corresponding to the location of the smoke detector under test for each smoke-generating pulse is determined. The number of times the state change time falls within different pulse arrival time periods is counted, and the phase distribution of the state change time relative to the corresponding smoke-generating pulse is determined. The degree of time correlation is determined based on the degree of deviation of the phase distribution from the uniform distribution. When the state change time is concentrated in a preset phase range of the smoke-producing pulse and the degree of time correlation reaches a preset correlation threshold, the degree of time correlation is determined to meet the preset correlation condition.

2. The method according to claim 1, characterized in that, Also includes: If the time correlation obtained by retesting does not meet the preset correlation condition, in at least two retesting processes, the aerosol average output rate, the wind speed and temperature in the fire detector test chamber are respectively within the corresponding preset deviation range, and different pulse coding sequences or different phase perturbation methods are used. When the time correlation obtained from at least two re-detections does not meet the preset correlation condition, the response time and alarm smoke density of the smoke detector under test are determined based on the alarm time of the smoke detector under test and the smoke density corresponding to the alarm time in each re-detection. When the time correlation obtained from any re-detection reaches the preset correlation condition, the alarm time and alarm smoke density of the corresponding detection process are marked as invalid detection data affected by periodic aliasing.

3. The method according to claim 1, characterized in that, The step of changing the time interval between adjacent smoke-producing pulses according to a predetermined pulse coding sequence includes: The time interval between each adjacent smoke-producing pulse is selected sequentially from a plurality of preset time intervals according to the predetermined pulse coding sequence; Based on the target smoke addition rate and the preset statistical period, the aerosol output corresponding to each smoke production pulse within the preset statistical period is determined, so that the total aerosol output within the preset statistical period meets the target smoke addition rate, and the average aerosol output rate corresponding to different preset statistical periods is within the preset rate deviation range.

4. The method according to claim 1, characterized in that, The step of changing the predetermined pulse coding sequence or applying a phase perturbation to the output time of the smoke-generating pulse includes: Select a candidate pulse coding sequence from multiple candidate pulse coding sequences that has a different time interval arrangement relationship with the currently used predetermined pulse coding sequence; or, While keeping the number of smoke-generating pulses and the total aerosol output constant within a preset statistical period, different time offsets are applied to the output times of at least some of the smoke-generating pulses within the preset statistical period. Re-detection is performed using the selected candidate pulse coding sequence or the smoke-producing pulse sequence after applying the time offset.

5. The method according to claim 1, characterized in that, Also includes: In the continuous aerosol output by the aerosol generator, low-dose aerosol marker pulses with predetermined time codes are inserted at predetermined time intervals; Smoke concentration change information was collected at at least two smoke detection locations set along the aerosol flow direction inside the fire detector test chamber. The aerosol marker pulses are identified from the smoke concentration change information collected at each of the smoke detection locations to determine the arrival time, peak value, pulse width, and attenuation degree of the aerosol marker pulses at each of the smoke detection locations.

6. The method according to claim 5, characterized in that, Also includes: Based on the differences in arrival time, pulse width variation, peak attenuation, and residual degree of the aerosol marker pulses at different smoke detection locations, as well as the residual degree after multiple cycles in the fire detector test chamber, the residence time distribution and aging degree of the aerosols in the fire detector test chamber are determined. Based on the residence time distribution and the degree of aging, the aerosol output of the aerosol generating device and the ratio between the newly generated aerosol and the circulating aerosol in the fire detector test chamber are adjusted so that the smoke density and aerosol aging degree of the smoke detector under test are within the corresponding preset ranges.

7. A smoke detector detection system, characterized in that, The system, employing the method as described in any one of claims 1 to 6, comprises: The delivery unit is used to place the smoke detector under test in the fire detector test chamber and control the aerosol generator to deliver aerosol into the fire detector test chamber. The aerosol generator outputs the aerosol with multiple smoke-generating pulses through an electromagnetic pulse valve. The adjustment unit is used to change the time interval between adjacent smoke-generating pulses according to a predetermined pulse coding sequence, so that the multiple smoke-generating pulses form a non-equal interval smoke-generating pulse sequence. The acquisition unit is used to acquire the status output information of the smoke detector under test during the action of the non-equal interval smoke-generating pulse sequence, and record the time of status change corresponding to the status output information; The determining unit is used to determine the degree of time correlation between the state change of the smoke detector under test and the predetermined pulse coding sequence based on the output time of each smoke-generating pulse and the state change time. The analysis unit is used to determine, when the time correlation reaches a preset correlation condition, that the current detection process is affected by the periodic aliasing between the smoke-generating pulse and the internal sampling period of the smoke detector under test, and to change the predetermined pulse coding sequence or apply a phase perturbation to the output time of the smoke-generating pulse in order to re-detect the smoke detector under test.

8. An electronic device, characterized in that, The electronic device includes at least one processor and at least one memory connected to the processor, wherein the processor is used to call program instructions in the memory to execute the smoke detector detection method as described in any one of claims 1 to 6.

9. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the storage medium to perform the smoke detector detection method as described in any one of claims 1 to 6.

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