Method and system for efficiently testing response threshold value of smoke fire detector

Abstract

The invention discloses a method and a system for efficiently testing a response threshold value of a smoke fire detector, relates to the technical field of smoke fire detectors, and solves the technical problem of large timing error caused by communication delay between a fire alarm controller and the detector. Smoke in a test environment is exhausted, and an A / B standard head and a detector to be tested start counting; smoke is added into the test environment, the A / B standard heads and the to-be-tested detectors detect the smoke concentration, the detectors stop counting when the detectors reach the fire alarm state, and all the to-be-tested detectors stop counting when all the B standard heads reach the fire alarm state; according to the A / B standard head and the count value of the to-be-detected detector, obtaining a qualified to-be-detected detector, and calculating a response threshold value of the qualified to-be-detected detector; accurate measurement of the response threshold value of the detector is realized, the communication efficiency between the fire alarm controller and the detector is improved, and timing errors caused by low communication speed are reduced.

Description

Technical Field

[0001] The invention belongs to the field of smoke fire detectors, and in particular relates to a method and a system for efficiently testing a response threshold value of a smoke fire detector. Background Art

[0002] The basic structure and working principle of a photoelectric smoke detector is that a set of light emitting elements (such as LEDs or laser diodes) and light receiving elements (such as photodiodes) are installed in a carefully designed optical maze. Under normal circumstances, the light emitted by the emitting element directly shines on the receiving element. However, when fire smoke particles in the air enter the optical maze of the detector, these particles will scatter the light, causing part of the originally direct light to deviate from the path and shine on the photoelectric receiving element, thereby generating an electrical signal proportional to the smoke concentration. Since the electrical characteristics of the emitting and receiving elements in different detectors and their specific positions in the maze may vary, this will cause the sensitivity of each detector to vary.

[0003] In order to ensure that every photoelectric smoke detector shipped out of the factory meets the specified sensitivity standards, each detector must be tested for response thresholds during the production process and unqualified products must be eliminated. The traditional testing method is to test the detectors one by one in a standard smoke box. Although this method is accurate, it is inefficient and cannot meet the needs of modern efficient production. If the detectors are tested in batches, there is a problem of large errors in the test results due to the communication delay between the fire alarm controller and the detectors.

[0004] Therefore, the present invention provides a method and system for efficiently testing the response threshold of a smoke fire detector. 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 a smoke fire detector, which is used to solve the technical problem of large test result errors caused by communication delays between a fire alarm controller and a detector.

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

[0007] Step 1: Build a test environment for the detector; wherein the test environment is provided with a number of A / B standard heads and a number of detectors to be tested;

[0008] Step 2: Exhaust all smoke from the test environment, and the A / B standard head and the detector to be tested start counting;

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

[0010] When all B standard heads reach the fire alarm state, all detectors to be tested stop counting;

[0011] Step 4: Obtain the count values ​​of the A / B standard head and the detector to be tested and the response threshold of the A / B standard head to determine whether the detector to be tested is qualified; if yes, retain the detector to be tested as qualified and calculate the response threshold of the qualified detector to be tested; if no, remove the detector to be tested; wherein the count value is the number of collected data.

[0012] Preferably, the counting frequencies of the A / B standard head and the detector to be tested are timed wake-up frequencies set by a detector program; wherein the counting start times of the A / B standard head and the detector to be tested are consistent.

[0013] Preferably, the step of determining whether the detector to be tested is qualified includes:

[0014] The average count values ​​based on the A / B standard heads are ∑a i / N a ,∑b j / N a , the counting value range of the qualified detector to be tested is [∑a i / N a ,∑b j / N b ];

[0015] When the count value of the detector under test is [∑a i / N a ,∑b j / N b ], the detector to be tested is a qualified detector, otherwise it is an unqualified detector; where i is the number of the A standard head, i = 0, 1, ..., N a , N a is a positive integer, a i is the count value of the A standard header numbered i, N a is the number of A standard headers; j is the number of B standard headers, j = 0, 1, ..., N b , N b is a positive integer, b i is the count value of the B standard header numbered j, N b is the number of B standard headers.

[0016] The present invention can test multiple detectors at the same time by introducing a multi-channel parallel testing system; specifically, the host computer determines the counting value range of qualified detectors to be tested based on the average counting value of the A / B standard head; when the counting value of the detector to be tested falls within this range, it is judged to be qualified; otherwise, it is unqualified; this batch testing method greatly improves the testing efficiency, shortens the production cycle, and reduces the cost.

[0017] Preferably, the step of calculating the response threshold of the qualified detector to be tested includes:

[0018] By formula Calculate the response threshold m of the qualified detector to be tested k ;

[0019] Among them, m a,i is the response threshold of the A standard header; m b,j is the response threshold of the B standard head; k is the number of the qualified detector to be tested, k = 0, 1, ..., Q, Q is a positive integer, c k is the count value of the qualified detector to be tested with number k.

[0020] Preferably, the A / B standard head refers to a smoke detector tested by a standard instrument; wherein the response threshold of the A standard head is at the lower limit level of the qualified range; and the response threshold of the B standard head is at the upper limit level of the qualified range.

[0021] Preferably, the method further includes step five: analyzing the normal fluctuation range of the qualified detector response threshold; determining whether the qualified detector response threshold 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 analysis qualified detector response threshold includes:

[0023] The mean value and variance of the qualified detector response threshold are calculated, marked as u and σ respectively; and based on the normal distribution characteristics, the normal fluctuation range of the qualified detector response threshold is obtained to be 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 fire detector, comprising a smoke box, a smoke exhaust valve, a fan, a plurality of A standard heads, a plurality of B standard heads, a load vehicle, a controller and a host computer;

[0025] The bottom of the smoke box is provided with a smoke feeding slot for placing ignited objects to generate smoke; a plurality of fans are provided inside the smoke box for stirring the smoke in the smoke box evenly; the smoke box is provided with a smoke exhaust valve, which is closed during the test and opened after the test is completed to exhaust the smoke;

[0026] A number of A / B standard heads are installed at specific positions in the smoke box to detect the smoke concentration in the smoke box; wherein the specific positions are pre-set positions;

[0027] The load vehicle is provided with a plurality of detectors to be tested, which are used for batch testing of the detectors;

[0028] The controller communicates with the A / B standard head and the detector to be tested 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 test process, calculate and save the test result data.

[0030] Preferably, the controller establishes communication with the A / B standard head and the detector to be tested via a fire alarm system bus, and the controller sends a broadcast command to start counting the A / B standard head and the detector to be tested.

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

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The system of the present invention adopts the A / B standard head method to equivalently test the response threshold of the detector, and can directly use the bus communication mechanism of the automatic fire alarm system for communication, avoiding the extra development work caused by the use of standard instruments, and has the characteristics of low cost and simple development; and uses a load vehicle to test a number of detectors to be tested at the same time, with high detection efficiency, meeting the needs of modern efficient production;

[0034] 2. The present invention calculates the response threshold of a qualified detector to be tested by obtaining the count values ​​of the A / B standard head and the detector to be tested and the response threshold of the A / B standard head; this method uses a distributed timing method to calculate the alarm time of the detector to be tested, which solves the problem of large timing errors caused by communication delays between the fire alarm controller and the detector, and realizes accurate measurement of the detector response threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 It is a schematic diagram of the process of the present invention;

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

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Photoelectric smoke detectors are devices used to detect smoke from fires. They use optical principles to identify the presence of smoke in the environment. This type of detector is an integral part of modern fire alarm systems and is widely used in homes, commercial and industrial locations.

[0040] Photoelectric smoke detectors mainly rely on the principle of light scattering or light interruption. Among them, the light scattering (forward scattering) type: there is a light source (usually a light-emitting diode LED) and a photosensitive sensor inside the detector. 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 will scatter the light, so that part of the light is captured by the photosensitive sensor, thereby triggering an alarm.

[0041] When fire smoke particles in the air enter the optical maze of the detector, these particles scatter light, causing part of the originally direct light to deviate from the path and shine on the photoelectric receiving element, thereby generating an electrical signal proportional to the smoke concentration. Since the electrical characteristics of the transmitting and receiving elements in different detectors and their specific positions in the maze may vary, this will cause the sensitivity of each detector to vary.

[0042] In order to quickly determine whether each photoelectric smoke detector shipped out of the factory meets the specified sensitivity standard, the present invention provides a method and system for efficiently testing the response threshold of a smoke fire detector.

[0043] See also Figure 1 The first aspect of the present invention provides a method for efficiently testing the response threshold of a smoke fire detector, comprising the following steps:

[0044] Step 1: Build the detector test environment;

[0045] Among them, a number of A / B standard heads and a number of detectors to be tested are set in the test environment to detect the smoke concentration in the test environment;

[0046] The counting frequency of the A / B standard head and the detector to be tested is the timed wake-up frequency set by the detector program; the counting start time of the A / B standard head and the detector to be tested is the same. For example: if the detector wakes up once every 0.5S, the counting frequency will increase by two count values ​​per second.

[0047] A standard head refers to a smoke detector tested by a standard instrument, and its response threshold is at the lower limit of the qualified range, that is, it responds more sensitively to fire smoke; B standard head refers to a smoke detector tested by a standard instrument, and its response threshold is at the upper limit of the qualified range, that is, it responds less sensitively to fire smoke; among them, the qualified 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 produce false alarms for non-fire factors (such as steam, dust, etc.), causing unnecessary panic and waste of resources. If the standard head is too slow, it may not be able to detect early fires in time, thus delaying the alarm timing. Therefore, the present invention sets two types of standard heads, sensitive and insensitive, and can give timely warnings within the response threshold range of the two.

[0049] Step 2: Exhaust all smoke from the test environment, and the A / B standard head and the detector to be tested start counting;

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

[0051] When all B standard heads reach the fire alarm state, all detectors to be tested stop counting;

[0052] Step 4: Obtain the count values ​​of the A / B standard head and the detector to be tested and the response threshold of the A / B standard head to determine whether the detector to be tested is qualified; if yes, retain the detector to be tested as qualified and calculate the response threshold of the qualified detector to be tested; if no, remove the detector to be tested; wherein the count value is the number of collected data;

[0053] Specifically, the average count values ​​based on the A / B standard headers are ∑a i / N a ,∑b j / N a , the counting value range of the qualified detector to be tested is [∑a i / N a ,∑b j / N b ];

[0054] When the count value of the detector under test is [∑a i / N a ,∑b j / N b], the detector to be tested is a qualified detector, otherwise it is an unqualified detector.

[0055] Where i is the number of the A standard header, i = 0, 1, ..., N a , N a is a positive integer, a i is the count value of the A standard header numbered i, N a is the number of A standard headers; j is the number of B standard headers, j = 0, 1, ..., N b , N b is a positive integer, b i is the count value of the B standard header numbered j, N b is the number of 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 the response threshold of the A / B standard head, and then the count value of the qualified detector to be tested is substituted into the relationship to calculate the response threshold of the qualified detector;

[0057] The response threshold m of the qualified detector k :

[0058]

[0059] Among them, m a,i is the response threshold of the A standard header; m b,j is the response threshold of the B standard head; k is the number of the qualified detector to be tested, k = 0, 1, ..., Q, Q is a positive integer, c k is the count value of the qualified detector to be tested with number k.

[0060] It should be noted that, because the acquisition cycles of the A / B standard head and the detector to be tested are the same, the count value is directly used to analyze the response threshold of the qualified detector to be tested.

[0061] As another preferred embodiment of the present invention, it also includes step five: analyzing the normal fluctuation range of the qualified detector response threshold to determine whether the qualified detector response threshold exceeds the normal fluctuation range; if yes, the test environment is abnormal; if not, the test environment is normal.

[0062] Among them, the normal fluctuation range of the qualified detector response threshold is analyzed as follows:

[0063] The mean value and variance of the qualified detector response threshold are calculated, marked as u and σ respectively; and based on the normal distribution characteristics, the normal fluctuation range of the qualified detector response threshold is obtained to be u±2σ or u±3σ.

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

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

[0066] A smoke feeding slot is provided at the bottom of the smoke box for placing ignited objects to generate smoke; a number of fans are provided inside the smoke box for stirring the smoke in the smoke box evenly; the smoke box is provided with a smoke exhaust valve, which is closed during the test and opened after the test is completed to exhaust the smoke;

[0067] Several A / B standard heads are used to detect the smoke concentration in the smoke box;

[0068] A standard head refers to a smoke detector tested by a standard instrument, with a response threshold at the lower limit of the qualified range, installed at a specific position in the smoke box; B standard head refers to a smoke detector tested by a standard instrument, with a response threshold at the upper limit of the qualified range, installed at a specific position in the smoke box; the specific position is a pre-set position;

[0069] Several detectors to be tested are arranged in the load vehicle for batch testing of the detectors;

[0070] The controller communicates with the A / B standard head and the detector to be tested 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 A / B standard head and the detector to be tested through the bus of the automatic fire alarm system, and the controller sends a broadcast command to make the A / B standard head and the detector to be tested start counting.

[0071] Among them, the broadcast command is used to realize "one-to-many" communication. All standard heads and detectors to be tested on the bus will perform corresponding operations after receiving the command.

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

[0073] Part of the data in the above formula is calculated by removing the dimension and taking its numerical value. The formula is a formula closest to the actual situation obtained by software simulation of a large amount of collected data; the preset parameters and preset thresholds in the formula are set by technical personnel in this field according to actual conditions or obtained through simulation of a large amount of data.

[0074] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A method for efficiently testing the response threshold of a smoke fire detector, characterized in that: The following steps are involved: Step 1: Build a test environment for the detector; wherein the test environment is provided with a number of A / B standard heads and a number of detectors to be tested; Step 2: Exhaust all smoke from the test environment, and the A / B standard head and the detector to be tested start counting; Step 3: Add smoke into the test environment, and the A / B standard head and the detector to be tested detect the smoke concentration. When the detector reaches the fire alarm state, the detector stops counting; and, When all B standard heads reach the fire alarm state, all detectors to be tested stop counting; Step 4: Obtain the count values ​​of the A / B standard head and the detector to be tested and the response threshold of the A / B standard head to determine whether the detector to be tested is qualified; if yes, retain the detector to be tested as qualified and calculate the response threshold of the qualified detector to be tested; if no, remove the detector to be tested; wherein the count value is the number of collected data.

2. A method for efficiently testing the response threshold of a smoke fire detector according to claim 1, characterized in that: The counting frequencies of the A / B standard head and the detector to be tested are timed wake-up frequencies set by the detector program; wherein the counting start times of the A / B standard head and the detector to be tested are consistent.

3. The method for efficiently testing the response threshold of a smoke fire detector according to claim 1, characterized in that: The step of judging whether the detector to be tested is qualified comprises: The average count values ​​based on the A / B standard heads are ∑a i / N a ,∑b j / N b , the counting value range of the qualified detector to be tested is [∑a i / N a ,∑b j / N b ]; When the count value of the detector under test is [∑a i / N a ,∑b j / N b ], the detector to be tested is a qualified detector, otherwise it is an unqualified detector; where i is the number of the A standard head, i = 0, 1, ..., N a , N a is a positive integer, a i is the count value of the A standard header numbered i, N a is the number of standard headers of A; j is the number of standard headers of B, j = 0, 1, ..., N b , N b is a positive integer, b i is the count value of the B standard header numbered j, N b is the number of B standard headers.

4. A method for efficiently testing the response threshold of a smoke fire detector according to claim 3, characterized in that: The step of calculating the response threshold of the qualified detector to be tested includes: By formula Calculate the response threshold m of the qualified detector to be tested k ; Among them, m a,i is the response threshold of the A standard header; m b,j is the response threshold of the B standard head; k is the number of the qualified detector to be tested, k = 0, 1, ..., Q, Q is a positive integer, c k is the count value of the qualified detector to be tested with number k.

5. The method for efficiently testing the response threshold of a smoke fire detector according to claim 3, characterized in that: The A / B standard head refers to a smoke detector tested by a standard instrument; wherein the response threshold of the A standard head is at the lower limit level of the qualified range; and the response threshold of the B standard head is at the upper limit level of the qualified range.

6. The method for efficiently testing the response threshold of a smoke fire detector according to claim 1, characterized in that: The step also includes step 5: analyzing the normal fluctuation range of the qualified detector response threshold; determining whether the qualified detector response threshold exceeds the normal fluctuation range; if yes, the test environment is abnormal; No, the test environment is normal.

7. A method for efficiently testing the response threshold of a smoke fire detector according to claim 6, characterized in that: The normal fluctuation range of the response threshold of the qualified detector includes: The mean value and variance of the qualified detector response threshold are calculated, marked as u and σ respectively; and based on the normal distribution characteristics, the normal fluctuation range of the qualified detector response threshold is obtained to be u±2σ or u±3σ.

8. A system for efficiently testing the response threshold of a smoke fire detector, based on the method for efficiently testing the response threshold of a smoke fire detector according to any one of claims 1 to 7, characterized in that: Including smoke box, smoke exhaust valve, fan, several A standard heads, several B standard heads, load car, controller and host computer; The bottom of the smoke box is provided with a smoke feeding slot for placing ignited objects to generate smoke; a plurality of fans are provided inside the smoke box for stirring the smoke in the smoke box evenly; the smoke box is provided with a smoke exhaust valve, which is closed during the test and opened after the test is completed to exhaust the smoke; A number of A / B standard heads are installed at specific positions in the smoke box to detect the smoke concentration in the smoke box; wherein the specific positions are pre-set positions; The load vehicle is provided with a plurality of detectors to be tested, which are used for batch testing of the detectors; The controller communicates with the A / B standard head and the detector to be tested through the bus of the automatic fire alarm system, and communicates with the host computer through the serial port; The host computer is used to control the test process, calculate and save the test result data.

9. A system for efficiently testing the response threshold of a smoke fire detector according to claim 8, characterized in that: The controller establishes communication with the A / B standard head and the detector to be tested via the automatic fire alarm system bus, and the controller sends a broadcast command to make the A / B standard head and the detector to be tested start counting.

10. The system for efficiently testing the response threshold of a smoke fire detector according to claim 9, characterized in that: The broadcast command is used to realize "one-to-many" communication. All standard heads and detectors to be tested on the bus will perform corresponding operations after receiving the command.

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