A method and system for efficiently testing the response threshold of a smoke detector

Abstract

The application discloses a kind of method and system for efficiently testing the response threshold of smoke fire detector, it is related to the technical field of smoke fire detector, solve the technical problem that the big timing error caused by communication delay between fire alarm controller and detector;The application exhausts the smoke in test environment, pre-defined A standard head, pre-defined B standard head and the start counting of to-be-tested detector;Add smoke to test environment, pre-defined A standard head, pre-defined B standard head and to-be-tested detector detect smoke concentration, when detector reaches fire alarm state, the detector stops counting, and when all pre-defined B standard head reaches fire alarm state, then all to-be-tested detector stops counting;According to the counting value of pre-defined A standard head, pre-defined B standard head and to-be-tested detector, obtain qualified to-be-tested detector, and calculate the response threshold of qualified to-be-tested detector;Realize the accurate measurement of the response threshold of detector, improve the communication efficiency between fire alarm controller and detector, reduce the timing error caused by low communication speed.

Description

Technical Field

[0001] This invention belongs to the field of smoke detectors, specifically a method and system for efficiently testing the response threshold of smoke detectors. Background Technology

[0002] The basic structure and working principle of a photoelectric smoke detector is as follows: within a carefully designed optical maze, a set of light-emitting elements (such as LEDs or laser diodes) and light-receiving elements (such as photodiodes) are installed. Under normal circumstances, the light emitted by the emitting elements directly illuminates the receiving elements. However, when smoke particles in the air enter the detector's optical maze, these particles scatter the light, causing some of the originally direct light to deviate from its path and illuminate the photoelectric receiving elements, thus generating an electrical signal proportional to the smoke concentration. Because the electrical characteristics of the emitting and receiving elements in different detectors and their specific positions within the maze may vary, this can lead to differences in sensitivity between different detectors.

[0003] To ensure that every photoelectric smoke detector meets the specified sensitivity standards before leaving the factory, each detector must undergo a response threshold test during the production process, and defective products must be rejected. The traditional testing method involves testing each detector individually in a standard smoke chamber. While accurate, this method is inefficient and cannot meet the needs of modern high-efficiency production. Furthermore, batch testing of detectors can lead to significant errors in the test results due to communication delays between the fire alarm controller and the detector.

[0004] Therefore, the present invention provides a method and system for efficiently testing the response threshold of smoke detectors. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art; to this end, the present invention proposes a method and system for efficiently testing the response threshold of smoke detectors, which is used to solve the technical problem of large test result errors caused by communication delay between fire alarm controllers and detectors.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for efficiently testing the response threshold of a smoke detector, comprising the following steps:

[0007] Step 1: Construct the test environment for the detector; the test environment includes several predefined A standard heads, a predefined B standard head, and several detectors under test;

[0008] Step 2: Expel the smoke from the test environment, and start counting with the predefined A standard head, the predefined B standard head, and the detector under test;

[0009] Step 3: Add smoke to the test environment. Predefined standard head A, predefined standard head B, and the detector under test detect the smoke concentration. When the detector reaches the fire alarm state, the detector stops counting; and...

[0010] When all predefined B standard heads reach the fire alarm state, all detectors under test stop counting;

[0011] Step 4: Obtain the count values ​​of the predefined A standard header, the predefined B standard header, and the detector under test, as well as the response thresholds of the predefined A standard header and the predefined B standard header, and determine whether the detector under test is qualified; if yes, retain the qualified detector under test and calculate the response threshold of the qualified detector under test; if no, remove the detector under test; where the count value is the number of data collected.

[0012] Preferably, the counting frequencies of the predefined A standard head, the predefined B standard head, and the detector under test are timed wake-up frequencies set by the detector program; wherein the counting start times of the predefined A standard head, the predefined B standard head, and the detector under test are consistent.

[0013] Preferably, determining whether the detector under test is qualified includes:

[0014] Based on the average count values ​​of predefined standard header A and predefined standard header B, respectively , The range of count values ​​obtained for qualified detectors under test is as follows: ;

[0015] When the count value of the detector under test is in If the value is within the range specified, the detector under test is a qualified detector; otherwise, it is a unqualified detector. Here, i is a predefined A standard header number, i = 0, 1, ... , It is a positive integer. The count value of the predefined A standard header for number i. The number of predefined A standard headers; j is the number of predefined B standard headers, j=0,1,… , It is a positive integer. The count value of the predefined B standard header for number j. The number of predefined B standard headers.

[0016] This invention introduces a multi-channel parallel testing system, which can test multiple detectors simultaneously. Specifically, the host computer determines the range of count values ​​for a qualified detector under test based on the average count values ​​of a predefined standard head A and a predefined standard head B. When the count value of the detector under test falls within this range, it is judged as qualified; otherwise, it is unqualified. This batch testing method greatly improves testing efficiency, reduces production cycle, and lowers costs.

[0017] Preferably, the calculation of the response threshold of the qualified detector under test includes:

[0018] Through formula The response threshold of a qualified detector under test is calculated. ;

[0019] in, The response threshold for the predefined A standard header; The response threshold of the predefined B standard head; k is the number of the qualified detector under test, k=0,1,…,Q, where Q is a positive integer. This is the count value of the qualified detector under test, number k.

[0020] Preferably, the predefined A standard head and the predefined B standard head refer to smoke detectors tested by standard instruments; wherein, the response threshold of the predefined A standard head is at the lower limit of the acceptable range; and the response threshold of the predefined B standard head is at the upper limit of the acceptable range.

[0021] Preferably, the method also includes step five: analyzing the normal fluctuation range of the response threshold of the qualified detector; determining whether the response threshold of the qualified detector exceeds the normal fluctuation range; if yes, the test environment is abnormal; if no, the test environment is normal.

[0022] Preferably, the normal fluctuation range of the response threshold of the qualified detector includes:

[0023] Calculate the mean and variance of the qualified detector response threshold, denoted as u and σ, respectively; and based on the normal distribution characteristics, obtain the normal fluctuation range of the qualified detector response threshold as u. 2σ or u 3σ.

[0024] Preferably, the second aspect of the present invention provides a system for efficiently testing the response threshold of a smoke detector, comprising a smoke box, a smoke exhaust valve, a fan, a plurality of predefined A standard heads, a plurality of predefined B standard heads, a load vehicle, a controller, and a host computer;

[0025] The bottom of the smoke box is equipped with a smoke inlet for placing igniting materials to generate smoke; the inside of the smoke box is equipped with several fans to stir the smoke inside the smoke box evenly; the smoke box is equipped with a smoke exhaust valve, which is closed during the test and opened after the test to remove the smoke.

[0026] If the intervention-defined standard head A and the predefined standard head B are installed at specific locations inside the smoke box, they are used to detect the smoke concentration inside the smoke box; where the specific location is a pre-set location;

[0027] The load vehicle is equipped with several detectors to be tested, which are used for batch testing of detectors;

[0028] The controller communicates with the predefined A standard header, the predefined B standard header, and the detector under test through the bus of the automatic fire alarm system, and communicates with the host computer through the serial port.

[0029] The host computer is used to control the testing process, calculate and save the test result data.

[0030] Preferably, the controller establishes communication with the predefined A standard head, the predefined B standard head, and the detector under test through the automatic fire alarm system bus, and the controller sends a broadcast command to start counting by the predefined A standard head, the predefined B standard head, and the detector under test.

[0031] Preferably, the broadcast command is used to achieve "one-to-many" communication, and all standard heads and detectors under test on the bus will perform corresponding operations after receiving the command.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. The system described in this invention uses a predefined A standard head and a predefined B standard head to equivalently test the response threshold of the detector. It can directly use the bus communication mechanism of the automatic fire alarm system for communication, avoiding the additional development work brought about by using standard instruments. It has the characteristics of low cost and simple development. Furthermore, it uses a load vehicle to test several detectors under test at the same time, which has high testing efficiency and meets the needs of modern high-efficiency production.

[0034] 2. This invention calculates the response threshold of a qualified detector by acquiring the count values ​​of a predefined A standard head, a predefined B standard head, and the detector under test, as well as the response thresholds of the predefined A standard head and the predefined B standard head. This method uses distributed timing to calculate the alarm time of the detector under test, solving the problem of large timing errors caused by communication delays between the fire alarm controller and the detector, and achieving accurate measurement of the detector response threshold. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0037] Figure 2 This is a block diagram of the system structure of the present invention. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] A photoelectric smoke detector is a device used to detect smoke generated by a fire. It uses optical principles to identify the presence of smoke in the environment. This type of detector is an indispensable part of modern fire alarm systems and is widely used in homes, businesses, and industrial settings.

[0040] Photoelectric smoke detectors primarily operate based on the principles of light scattering or light blocking. The light scattering (forward scattering) type detector contains a light source (usually an LED) and a photosensitive sensor. In the absence of smoke, the light beam passes directly through the detection chamber without being captured by the sensor. When smoke enters the detection chamber, the smoke particles scatter the light, causing some of the light to be captured by the photosensitive sensor, thus triggering an alarm.

[0041] When smoke particles from a fire enter the optical labyrinth of a detector, these particles scatter light, causing some of the originally direct light to deviate from its path and strike the photoelectric receiving element, thus generating an electrical signal proportional to the smoke concentration. Because the electrical characteristics of the transmitting and receiving elements in different detectors, as well as their specific positions within the labyrinth, may vary, this can lead to differences in sensitivity between the individual detectors.

[0042] In order to quickly determine whether each photoelectric smoke detector meets the prescribed sensitivity standards, this invention provides a method and system for efficiently testing the response threshold of smoke fire detectors.

[0043] Please see Figure 1The first aspect of this invention provides a method for efficiently testing the response threshold of a smoke detector, comprising the following steps:

[0044] Step 1: Construct the test environment for the detector;

[0045] The test environment is equipped with several predefined A standard heads, predefined B standard heads, and several detectors to be tested, which are used to detect the smoke concentration in the test environment.

[0046] The counting frequencies of the predefined A standard head, the predefined B standard head, and the detector under test are determined by the timed wake-up frequency set by the detector program; the counting start times of the predefined A standard head, the predefined B standard head, and the detector under test are consistent. For example, if the detector wakes up every 0.5 seconds, the counting frequency increases by two count values ​​per second.

[0047] The predefined A standard head refers to a smoke detector tested by a standard instrument, with a response threshold at the lower limit of the acceptable range, meaning it is highly sensitive to fire smoke. The predefined B standard head refers to a smoke detector tested by a standard instrument, with a response threshold at the upper limit of the acceptable range, meaning it is less sensitive to fire smoke. The acceptable range refers to the response threshold range for timely response to fire.

[0048] It should be noted that if the standard head is too sensitive, it may generate false alarms for non-fire factors (such as steam, dust, etc.), leading to unnecessary panic and waste of resources. If the standard head is too insensitive, it may fail to detect early fires in time, thus delaying the alarm. Therefore, this invention sets up two types of standard heads: sensitive and insensitive. When the response thresholds of both are within the range of their respective thresholds, timely warnings can be issued.

[0049] Step 2: Expel the smoke from the test environment, and start counting with the predefined A standard head, the predefined B standard head, and the detector under test;

[0050] Step 3: Add smoke to the test environment. Predefined standard head A, predefined standard head B, and the detector under test detect the smoke concentration. When the detector reaches the fire alarm state, the detector stops counting; and...

[0051] When all predefined B standard heads reach the fire alarm state, all detectors under test stop counting;

[0052] Step 4: Obtain the count values ​​of the predefined A standard head, the predefined B standard head, and the detector under test, as well as the response thresholds of the predefined A standard head and the predefined B standard head, and determine whether the detector under test is qualified; if yes, retain the qualified detector under test and calculate the response threshold of the qualified detector under test; if no, remove the detector under test; where the count value is the number of data collected.

[0053] Specifically, based on the average count values ​​of the predefined A standard header and the predefined B standard header, respectively , The range of count values ​​obtained for qualified detectors under test is as follows: ;

[0054] When the count value of the detector under test is in If the result is within the acceptable range, the detector under test is a qualified detector; otherwise, it is an unqualified detector.

[0055] Where i is the predefined A standard header number, i = 0, 1, ... , It is a positive integer. The count value of the predefined A standard header for number i. The number of predefined A standard headers; j is the number of predefined B standard headers, j=0,1,… , It is a positive integer. The count value of the predefined B standard header for number j. The number of predefined B standard headers.

[0056] The first-order function relationship between the count value and the response threshold is obtained by fitting the count value and response threshold of the predefined A standard head and the predefined B standard head. Then, the count value of the qualified detector under test is substituted into the relationship to calculate the response threshold of the qualified detector.

[0057] Response threshold of a qualified detector :

[0058] ;

[0059] in, The response threshold for the predefined A standard header; The response threshold of the predefined B standard head; k is the number of the qualified detector under test, k=0,1,…,Q, where Q is a positive integer. This is the count value of the qualified detector under test, number k.

[0060] It should be noted that since the predefined A standard head, the predefined B standard head, and the detector under test have the same acquisition period, the count value is directly used to analyze the response threshold of the qualified detector under test.

[0061] As another preferred embodiment of the present invention, it further includes step five: analyzing the normal fluctuation range of the response threshold of the qualified detector, and determining whether the response threshold of the qualified detector exceeds the normal fluctuation range; if yes, then there is an abnormality in the test environment; if no, then the test environment is normal.

[0062] The normal fluctuation range of the response threshold of a qualified detector is analyzed as follows:

[0063] Calculate the mean and variance of the qualified detector response threshold, denoted as u and σ, respectively; and based on the normal distribution characteristics, obtain the normal fluctuation range of the qualified detector response threshold as u. 2σ or u 3σ.

[0064] It should be noted that, according to statistical theory, for normally distributed data, a 95% confidence interval means approximately 95% of the data points will fall within the mean plus or minus two standard deviations; a 99.7% confidence interval means approximately 99.7% of the data points will fall within the mean plus or minus three standard deviations. These two intervals are respectively called the "2σ" and "3σ" control limits. In industrial practice, the 3σ control limit is more commonly used because it provides a more stringent standard for anomaly detection.

[0065] Please see Figure 2 The second aspect of the present invention provides a system for efficiently testing the response threshold of a smoke detector, comprising a smoke box, a smoke exhaust valve, a fan, a plurality of predefined A standard heads, a plurality of predefined B standard heads, a load vehicle, a controller, and a host computer;

[0066] The bottom of the smoke box is equipped with a smoke inlet for placing igniting materials to generate smoke; several fans are installed inside the smoke box to mix the smoke evenly; the smoke box is equipped with an exhaust valve, which is closed during the test and opened after the test to remove the smoke.

[0067] If the intervention-defined standard head A and the predefined standard head B are used to detect the smoke concentration inside the smoke box;

[0068] The predefined A standard head refers to a smoke detector tested by a standard instrument, with a response threshold at the lower limit of the acceptable range, installed at a specific location inside the smoke chamber; the predefined B standard head refers to a smoke detector tested by a standard instrument, with a response threshold at the upper limit of the acceptable range, installed at a specific location inside the smoke chamber; where the specific location is a pre-set position.

[0069] The load vehicle is equipped with several detectors under test for batch testing of detectors;

[0070] The controller communicates with the predefined A standard head, the predefined B standard head, and the detector under test through the bus of the automatic fire alarm system, and communicates with the host computer through the serial port. The controller establishes communication with the predefined A standard head, the predefined B standard head, and the detector under test through the bus of the automatic fire alarm system, and sends a broadcast command to start counting by the predefined A standard head, the predefined B standard head, and the detector under test.

[0071] The broadcast command is used to achieve "one-to-many" communication. All standard headers and detectors under test on the bus will perform corresponding operations after receiving the command.

[0072] The host computer is used to control the testing process, calculate and save the test results data.

[0073] Some of the data in the above formula are calculated by removing dimensions and taking their numerical values. The formula is the closest to the real situation obtained by software simulation of a large amount of collected data. The preset parameters and preset thresholds in the formula are set by those skilled in the art according to the actual situation or obtained through simulation of a large amount of data.

[0074] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A method of efficiently testing the response threshold of a smoke sensing fire detector, characterized by, The method comprises the following steps: Step 1: constructing a test environment for the detector; The test environment is provided with a controller, a plurality of predefined A standard heads, a plurality of predefined B standard heads and a plurality of detectors to be tested; the controller, the predefined A standard heads, the predefined B standard heads and the detectors to be tested are all connected to a fire automatic alarm system bus and are configured with the same counting frequency, which is determined by a timing wake-up frequency set by an internal program of the detector; wherein the predefined A standard heads and the predefined B standard heads are smoke detectors tested by a standard instrument, the response threshold of the predefined A standard heads is the lower limit value of the qualified range, and the response threshold of the predefined B standard heads is the upper limit value of the qualified range; Step 2: exhausting the smoke in the test environment, and sending a broadcast command by the controller through the fire automatic alarm system bus to make the predefined A standard heads, the predefined B standard heads and the detectors to be tested start counting at the same time; the broadcast command is used to realize one-to-many communication, and all the standard heads and the detectors to be tested on the fire automatic alarm system bus will execute corresponding operations after receiving the command; Step 3: adding smoke into the test environment, and detecting the smoke concentration by the predefined A standard heads, the predefined B standard heads and the detectors to be tested, and stopping counting when the detector reaches a fire alarm state; and stopping counting when all the predefined B standard heads reach the fire alarm state; Step 4: acquiring the counting values of the predefined A standard heads, the predefined B standard heads and the detectors to be tested, and the response thresholds of the predefined A standard heads and the predefined B standard heads, and judging whether the detector to be tested is qualified; if yes, retaining the detector to be tested as qualified and calculating the response threshold of the qualified detector to be tested; if no, discarding the detector to be tested; wherein the counting value is the number of collected data.

2. A method of testing the response threshold of a high efficiency smoke detector according to claim 1, wherein, The judgment of whether the detector to be tested is qualified comprises: Based on the average count value of the predefined A standard head, the predefined B standard head, respectively , , the count value range of the qualified detector to be tested is ; When the count value of the to-be-tested probe is within , the to-be-tested probe is a qualified probe, otherwise it is an unqualified probe; wherein i is the number of the predefined A standard head, i=0, 1, …, , is a positive integer, is the count value of the predefined A standard head numbered i, is the number of the predefined A standard head; j is the number of the predefined B standard head, j=0, 1, …, , is a positive integer, is the count value of the predefined B standard head numbered j, is the number of the predefined B standard head.

3. A method of testing the response threshold of a high efficiency smoke fire detector according to claim 2, wherein, The calculation of the response threshold of the qualified detector to be tested comprises: The response threshold of the qualified detector to be tested is calculated by the formula ;​ wherein, is a predefined response threshold for A standard heads; is a predefined response threshold for B standard heads; k is the number of qualified detectors under test, k = 0, 1, …, Q, Q is a positive integer, is the count value of the qualified detector under test with number k.

4. A method of testing the response threshold of a high efficiency smoke fire detector according to claim 2, wherein, The predefined A standard heads and the predefined B standard heads refer to smoke detectors tested by a standard instrument; wherein the response threshold of the predefined A standard heads is at the lower limit level of the qualified range, and the response threshold of the predefined B standard heads is at the upper limit level of the qualified range.

5. The method of testing the response threshold of a high efficiency smoke detector of claim 1 wherein, Further comprising Step 5: analyzing the normal fluctuation range of the response threshold of the qualified detector; judging whether the response threshold of the qualified detector exceeds the normal fluctuation range; if yes, the test environment is abnormal; if no, the test environment is normal.

6. A method of testing the response threshold of a high efficiency smoke fire detector according to claim 5, wherein, The analysis of the normal fluctuation range of the response threshold of the qualified detector comprises: The average and variance of the qualified detector response threshold are calculated, respectively marked as u and σ; and based on the normal distribution characteristics, the normal fluctuation range of the qualified detector response threshold is obtained as u 2σ or u 3σ.

7. A system for efficiently testing the response threshold of a smoke fire detector, operating on the basis of a method for efficiently testing the response threshold of a smoke fire detector according to any one of claims 1 to 6, characterized in that The test device comprises a smoke tank, a smoke exhaust valve, a fan, a plurality of predefined A standard heads, a plurality of predefined B standard heads, a load vehicle, a controller and an upper computer; The bottom of the smoke tank is provided with a smoke adding groove for placing a fire starter to generate smoke; a plurality of fans are arranged in the smoke tank to stir the smoke in the smoke tank uniformly; the smoke tank is provided with a smoke exhaust valve, which is closed during the test and opened after the test to exhaust the smoke; A plurality of predefined A standard heads and predefined B standard heads are installed in specific positions in the smoke box for detecting the smoke concentration in the smoke box; wherein the specific positions are pre-set positions; A plurality of to-be-tested detectors are arranged in the load vehicle for batch testing of the detectors; The controller communicates with the predefined A standard heads, the predefined B standard heads and the to-be-tested detectors through a fire automatic alarm system bus, and communicates with the upper computer through a serial port; The upper computer is used for controlling a test process, calculating and saving test result data.

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