Self-testing fire sensing device

Abstract

This invention is entitled "Self-Test Fire Detection Device". This document describes apparatus, methods, and systems for a self-test fire detection device. One apparatus includes: an adjustable particle generator and a variable airflow generator configured to generate an aerosol density level sufficient to trigger a fire response without saturating an optical scattering chamber; and an optical scattering chamber configured to measure the rate of decrease of the aerosol density level after it has been generated; to determine an airflow rate from the external environment through the optical scattering chamber based on the measured rate of decrease of the aerosol density level; and to determine whether the self-test fire detection device is functioning correctly based on the fire response and the determined airflow rate.

Description

[0001] This application is a divisional application of Chinese patent application filed on July 22, 2020, entitled "Self-Test Fire Sensing Device" with application number 202010713357.X. Technical Field

[0002] This disclosure relates in general to apparatus, methods, and systems for self-testing fire sensing devices. Background Technology

[0003] Large facilities (e.g., buildings), such as commercial facilities, office buildings, hospitals, etc., may have fire alarm systems that can be triggered during emergencies (e.g., fire) to warn occupants to evacuate. For example, a fire alarm system may include a fire control panel and multiple fire sensing devices (e.g., smoke detectors) distributed throughout the facility (e.g., on different floors and / or in different rooms) that can detect a fire occurring in the facility and notify the occupants of the fire via alarms.

[0004] Maintaining a fire alarm system may include mandatory periodic testing of fire sensing devices in accordance with operating procedures to ensure that the devices are functioning properly. However, because testing can only be performed periodically, there is a risk that faulty fire sensing devices may not be detected quickly or that not all fire sensing devices in the fire alarm system may be tested.

[0005] Typical tests involve maintenance engineers using pressurized aerosols to force synthetic smoke into the fire sensing device's chamber, saturating it. In some examples, maintenance engineers may also use a heat gun to raise the temperature of the thermal sensors in the fire sensing device and / or gas generator to expel carbon monoxide (CO) gas into the fire sensing device. These tests may not accurately mimic the characteristics of a fire, and therefore may not accurately determine the fire sensing device's ability to detect actual fires.

[0006] Moreover, manually testing each fire detection device can be time-consuming, costly, and disruptive to operations. For example, maintenance engineers are often required to connect fire detection devices located in areas occupied by building occupants or in typically inaccessible parts of the building (e.g., elevator shafts, high ceilings, suspended ceiling spaces). Therefore, maintenance engineers may need to spend several days and make multiple visits to complete the testing, especially in large sites. Additionally, many fire detection devices are often never tested due to connection issues. Attached Figure Description

[0007] Figure 1 An example of a self-testing fire sensing device according to an embodiment of this disclosure is shown.

[0008] Figure 2 A block diagram of the smoke self-test function of a fire sensing device according to an embodiment of the present disclosure is shown.

[0009] Figure 3 A block diagram of the thermal self-test function of a fire sensing device according to an embodiment of the present disclosure is shown.

[0010] Figure 4 A block diagram of the gas self-test function of a fire sensing device according to an embodiment of the present disclosure is shown.

[0011] Figure 5 A diagram showing the output of an exemplary optical scattering chamber for determining whether a fire sensing device is operating normally, according to an embodiment of the present disclosure. Detailed Implementation

[0012] This document describes an apparatus, method, and system for a self-testing fire sensing device. One apparatus includes: an adjustable particle generator and a variable airflow generator configured to generate an aerosol density level sufficient to trigger a fire response without saturating an optical scattering chamber; and an optical scattering chamber configured to measure the rate of decrease of the aerosol density level after it has been generated; to determine an airflow rate from the external environment through the optical scattering chamber based on the measured rate of decrease of the aerosol density level; and to determine whether the self-testing fire sensing device is functioning correctly based on the fire response and the determined airflow rate.

[0013] Compared to previous fire sensing devices where maintenance engineers had to manually test each fire sensing device in a facility (e.g., using pressurized aerosols, heat guns, gas generators, or any combination thereof), the fire sensing device according to this disclosure is self-testing and can more accurately mimic the characteristics of a fire. Therefore, the fire sensing device according to this disclosure can be tested in less time, can be tested continuously and / or on demand, and its ability to detect actual fires can be determined more accurately.

[0014] In the following detailed description, reference is made to the accompanying drawings, which form a part thereof. The drawings illustrate by way of example how one or more embodiments of this disclosure can be practiced.

[0015] These embodiments are described in sufficient detail to enable one or more embodiments of this disclosure to be practiced by a person skilled in the art. It should be understood that other embodiments may be utilized and mechanical, electrical and / or process changes may be made without departing from the scope of this disclosure.

[0016] It should be understood that elements shown in the various embodiments herein may be added, exchanged, combined, and / or eliminated to provide multiple additional embodiments of this disclosure. The scale and relative dimensions of the elements provided in the accompanying drawings are intended to illustrate embodiments of this disclosure and should not be construed as limiting.

[0017] The figures in this document follow the following numbering convention: one or more first digits correspond to the figure number, while the remaining digits identify elements or parts in the figure. Similar elements or parts in different figures can be identified by using similar digits. For example, Figure 1 The 104 in the text can reference the element "04", and Figure 2 Similar elements in this context can be referenced as 204.

[0018] As used in this article, "one" or "several" can refer to one or more such things, while "multiple" can refer to more than one such thing. For example, "numerous components" can refer to one or more components, while "multiple components" can refer to more than one component.

[0019] Figure 1 An example of a self-test fire sensing device 100 according to an embodiment of the present disclosure is shown. The self-test fire sensing device 100 may be, but is not limited to, a fire and / or smoke detector in a fire control system.

[0020] Fire sensing device 100 (e.g., smoke detector) can detect a fire occurring in the facility and trigger a fire response to notify the occupants of the fire. The fire response may include, for example, visual and / or audio alarms. The fire response may also notify emergency services (e.g., fire department, police station, etc.). In some examples, multiple fire sensing devices may be distributed throughout the facility (e.g., on different floors and / or in different rooms of the facility).

[0021] The self-test fire sensing device 100 can automatically or by command perform one or more tests included within the fire sensing device 100. These one or more tests determine whether the self-test fire sensing device 100 is functioning properly.

[0022] like Figure 1 As shown, the fire sensing device 100 may include an adjustable particle generator 102, an optical scattering chamber 104 including an emitter light-emitting diode (LED) 105 and a receiver photodiode 106, a heat source 108, a thermal sensor 110, a gas source 112, a gas sensor 114, a variable airflow generator 116, a proximity sensor 118, and an additional heat source 119. In some examples, the fire sensing device 100 may also include a microcontroller that includes memory and / or a processor, such as when combined with... Figures 2 to 4 Further description.

[0023] The adjustable particle generator 102 of the fire sensing device 100 can generate particles that can be mixed into a controlled aerosol density level by a variable airflow generator 116. The aerosol density level can be a specific level detectable by the optical scattering chamber 104. In some examples, a fire response can be triggered in response to the optical scattering chamber 104 detecting an aerosol density level. Once the aerosol density level has reached a specific level, the adjustable particle generator 116 can be shut off, and the variable airflow generator 116 can increase the airflow rate through the optical scattering chamber 104. The variable airflow generator 116 can increase the airflow rate through the optical scattering chamber 104 to reduce the aerosol density level back to the initial level of the optical scattering chamber 104 before the adjustable particle generator 116 generates particles. For example, the variable airflow generator 116 can remove aerosols from the optical scattering chamber 104 after determining that the fire sensing device 100 is operating normally. If the fire sensing device 100 is not obstructed or covered, airflow from the external environment through the optical scattering chamber 104 will cause the aerosol density level to decrease. After the aerosol density level has been generated, the rate of decrease of the aerosol density level is proportional to the airflow from the external environment through the optical scattering chamber 104. Therefore, the optical scattering chamber 104 can measure the airflow to determine whether the sensing device 100 is obstructed and whether the sensing device 100 is operating normally.

[0024] The adjustable particle generator 102 may include a reservoir to contain liquid and / or wax for forming particles. The adjustable particle generator 102 may also include a heat source, which may be heat source 108 or a different heat source. Heat source 108 may be a resistance wire coil. The current flowing through the wire can be used to control the temperature of heat source 108 and further control the number of particles generated by the adjustable particle generator 102. Heat source 108 can heat the liquid and / or wax to form aerosol particles to simulate smoke from a fire. The particles may be measurably about 1 micrometer in diameter, and / or the particles may be within the sensitivity range of optical scattering chamber 104. Heat source 108 can heat the liquid and / or wax to a specific temperature and / or heat the liquid and / or wax for a specific time period to generate an aerosol density level sufficient to trigger a fire response from a normally operating fire sensing device without saturating optical scattering chamber 104 and / or generate an aerosol density level sufficient to test fault conditions without triggering a fire response or saturating optical scattering chamber 104. The ability to control aerosol density levels allows smoke tests to more accurately mimic the characteristics of a fire and prevents the optical scattering chamber 104 from becoming saturated.

[0025] Because the baffle opening in the fire sensing device 100 allows air and / or smoke from a fire to flow through the fire sensing device 100, the optical scattering chamber 104 can sense the external environment. The optical scattering chamber 104 may be an example of an airflow monitoring device. In some examples, different airflow monitoring devices may be used to measure the airflow passing through the fire sensing device 100.

[0026] As previously discussed, the rate of decrease in aerosol density level can be used to determine the airflow rate from the external environment through optical scattering chamber 104, and the determined airflow rate and / or fire response can be used to determine whether the fire sensing device 100 is operating normally. For example, the fire sensing device 100 may be determined to be operating normally in response to the airflow rate exceeding a threshold airflow rate and / or the fire response being triggered. In some examples, the fire sensing device 100 may trigger a fault if the airflow rate fails to exceed the threshold airflow rate. For example, the fire sensing device 100 may send a fault notification to a monitoring device when obstructed airflow is detected. In some examples, obstructed airflow may be caused by a person intentionally attempting to obstruct (e.g., cover) the fire sensing device 100.

[0027] The fire sensing device 100 may include an additional heat source 119, but if the thermal sensor 110 is self-heating, the additional heat source 119 may not be required. In some examples, the heat source 119 may generate heat at a temperature sufficient to trigger a fire response from a normally operating thermal sensor 110. The heat source 119 may be turned on to generate heat during a thermal self-test. Once the thermal self-test is complete, the heat source 119 may be turned off to stop generating heat.

[0028] Thermal sensor 110 is typically used to detect temperature rises caused by a fire. Once the heat source 119 is turned off, thermal sensor 110 measures the rate of temperature decrease. The rate of temperature decrease is proportional to the airflow from the external environment through fire sensing device 100, and therefore, the rate of temperature decrease can be used to determine the airflow rate. The airflow rate can be used to determine whether air can enter fire sensing device 100 and reach thermal sensor 110. The airflow rate can also be measured and used to compensate for the generation of aerosols used for self-testing of fire sensing device 100.

[0029] A fire response can be triggered in response to the thermal sensor 110 detecting a temperature exceeding a threshold temperature. The operation of the fire sensing device 100 can be determined in response to the triggering of the fire response and the determined airflow rate.

[0030] A fault may be triggered by the fire sensing device 100 in response to a determined temperature change over time failing to exceed a threshold temperature change over time. In some examples, the fault may be sent to a monitoring device. The determined temperature change over time may determine whether the fire sensing device 100 is operating normally. In some examples, the fire sensing device 100 may be operating normally in response to an airflow rate derived from a determined temperature change over time exceeding a threshold airflow rate.

[0031] The gas source 112 may be separate and / or included in the adjustable particle generator 102, such as Figure 1As shown. Gas source 112 can be configured to release one or more gases. These gases can be generated by combustion. In some examples, the gases may be carbon monoxide (CO) and / or cross-sensitive gases. Gas source 112 can generate gas levels sufficient to trigger a fire response from a normally operating fire sensing device and / or trigger a fault in a normally operating gas sensor 114.

[0032] Gas sensor 114 can detect one or more gases in fire sensing device 100, such as one or more gases released, for example, by gas source 112. For example, gas sensor 114 can detect CO and / or cross-sensitive gases. In some examples, gas sensor 114 may be a CO detector. Once gas source 112 is turned off, gas sensor 114 can measure gas levels and determine changes in gas levels over time to determine airflow rate. Airflow rate can be used to determine whether air can enter fire sensing device 100 and reach gas sensor 114.

[0033] The fire sensing device 100 can be triggered to fire response in response to gas sensor 114 detecting one or more gases and / or one or more gases exceeding a threshold level. The fire sensing device 100 can be determined to be operating normally in response to the fire response, the gas sensor 114 detecting one or more gases and / or one or more gases exceeding a threshold level, and the fire sensing device 100 normally triggering a fire response.

[0034] The operation of the fire sensing device 100 can be determined based on changes in gas levels over time. In some examples, the operation of the fire sensing device 100 can be determined in response to a gas level change over time exceeding a threshold gas level change and / or an airflow rate obtained from a determined change in gas levels over time exceeding a threshold airflow rate. The fire sensing device 100 can trigger and / or send a fault in response to a gas level change over time failing to exceed a threshold gas level change and / or an airflow rate failing to exceed a threshold airflow rate. In some examples, the operation of the fire sensing device 100 can be determined in response to the triggering of a fire response and / or the triggering of a fault.

[0035] The variable airflow generator 116 can control the airflow through the first sensing device 100, which includes the optical scattering chamber 104. For example, the variable airflow generator 116 can move gas and / or aerosol from a first end of the fire sensing device 100 to a second end of the fire sensing device 100. In some examples, the variable airflow generator 116 can be a fan. The variable airflow generator 116 can be activated in response to the activation of the adjustable particle generator 102, the heat source 119, and / or the gas source 112. The variable airflow generator 116 can be stopped in response to the cessation of the adjustable particle generator 102, the heat source 119, and / or the gas source 112, and / or the variable airflow generator 116 can be stopped after a specific period of time after the adjustable particle generator 102, the heat source 119, and / or the gas source 112 has been stopped.

[0036] Fire sensing device 100 may include one or more proximity sensors 118. The proximity sensors 118 can detect objects within a specific distance of fire sensing device 100 and can therefore be used to detect tampering intended to prevent the proper functioning of fire sensing device 100. For example, the proximity sensors 118 can detect objects (e.g., a hand, a piece of clothing, etc.) placed in front of or above fire sensing device 100 to obstruct heat, gas, and / or smoke from entering optical diffusion chamber 104, attempting to prevent triggering a fire response from fire sensing device 100. In some examples, a fire response of fire sensing device 100 may be triggered in response to proximity sensor 118 detecting an object within a specific distance of fire sensing device 100.

[0037] Figure 2 A block diagram of a smoke self-test function 220 of a fire sensing device according to an embodiment of the present disclosure is shown. The block diagram of the smoke self-test function 220 includes a fire sensing device 200 and a monitoring device 201. The fire sensing device 200 includes a microcontroller 222, an adjustable particle generator 202, an optical scattering chamber 204, and a variable airflow generator 216.

[0038] Monitoring device 201 may be a control panel, a fire detection and control system, and / or a cloud computing device for a fire alarm system. Monitoring device 201 may be configured to send commands to and / or receive test results from fire sensing device 200 via wired or wireless networks. The network may be a network relationship through which monitoring device 201 communicates with fire sensing device 200. Examples of such network relationships may include distributed computing environments (e.g., cloud computing environments), wide area networks (WANs), local area networks (LANs), personal area networks (PANs), campus networks (CANs), or metropolitan area networks (MANs) such as the Internet, and other types of network relationships. For example, the network may include multiple servers that receive information from and transmit information to monitoring device 201 and fire sensing device 200 via wired or wireless networks.

[0039] As used herein, a “network” can provide a communication system that directly or indirectly links two or more computers and / or peripherals and allows monitoring devices to access data and / or resources on fire sensing device 200, and vice versa. A network can allow users to share resources on their own systems with other network users and access information on systems located at a central location or at a remote location. For example, a network can connect multiple computing devices together to form a distributed control network (e.g., a cloud).

[0040] A network provides connectivity to the Internet and / or to other entities' networks (e.g., organizations, institutions, etc.). Users can interact with network-enabled software applications to make network requests, such as retrieving data. Applications can also communicate with network management software, which interacts with network hardware to transfer information between devices on the network.

[0041] The microcontroller 222 may include a processor 224 and a memory 226. The memory 224 may be any type of storage medium accessible to the processor 226 to perform various examples of this disclosure. For example, the memory 224 may be a non-transitory computer-readable medium storing computer-readable instructions (e.g., computer program instructions) thereon, which the processor 226 is capable of executing to test the fire sensing device 200 according to this disclosure. For example, the processor 226 may execute executable instructions stored in the memory 224 to generate a specific aerosol density level, measure the generated aerosol density level, determine the airflow rate from the external environment through the optical scattering chamber 204, and transmit the determined airflow rate. In some examples, the memory 224 may store an aerosol density level sufficient to trigger a fire response from a normally operating fire sensing device, an aerosol density level sufficient to test a fault condition without triggering a fire response, a threshold airflow rate validating appropriate airflow through the optical scattering chamber 204, and / or a specific time period that has elapsed since a previous smoke self-test function (e.g., generating a specific aerosol density level and measuring the generated aerosol density level).

[0042] The microcontroller 222 may execute the smoke self-test function 220 of the fire sensing device 200 in response to a specific time period elapsed since the previous smoke self-test function and / or in response to a command received from the monitoring device 201.

[0043] The microcontroller 222 can send commands to the adjustable particle generator 202 to generate particles. Particles can be drawn through the optical scattering chamber 204 via the variable airflow generator 216, thereby creating a controlled aerosol density level. The aerosol density level is sufficient to trigger a fire response without saturating the optical scattering chamber. The aerosol density level can be measured, and the airflow rate can be determined via the optical scattering chamber 204. Figure 2 As shown, the scattering chamber 204 may include an emitter light-emitting diode (LED) 205 and a receiver photodiode 206 to measure aerosol density levels.

[0044] Once the aerosol density level has been measured and / or the airflow rate has been determined, the fire sensing device 200 can store the test results (e.g., fire response, aerosol density level, rate of decrease of the aerosol density level after it has been generated, and / or airflow rate) in memory 224 and / or send the test results to monitoring device 201. In some examples, the fire sensing device 200 can determine whether it is operating normally based on the test results, and / or the monitoring device 201 can determine whether it is operating normally based on the test results. For example, the monitoring device 201 can determine that the fire sensing device 200 is operating normally in response to the triggering of a fire response and / or the airflow rate exceeding a threshold airflow rate.

[0045] Figure 3 A block diagram of a thermal self-test function 330 of a fire sensing device according to an embodiment of the present disclosure is shown. The block diagram of the thermal self-test function 330 includes a fire sensing device 300 and a monitoring device 301. The fire sensing device 300 includes a microcontroller 322, a heat source 319, a thermal sensing element 310, and a variable airflow generator 316.

[0046] The microcontroller 322 may include a memory 324 and a processor 326. The memory 324 may be a non-transitory computer-readable medium storing computer-readable instructions (e.g., computer program instructions) thereon, which the processor 326 is capable of executing to test the fire sensing device 300 according to this disclosure. For example, the processor 326 may execute executable instructions stored in the memory 324 to generate heat using a heat source 319 at a temperature sufficient to trigger a fire response, detect an increase in temperature using a thermal sensor 310, shut off the heat source 319, measure the rate of temperature decrease, and / or determine an airflow rate based on the rate of temperature decrease. In some examples, the memory 324 may store a threshold temperature sufficient to trigger a fire response from a normally functioning thermal sensing element 310 and / or a time period that has elapsed since a previous thermal self-test function (e.g., generating heat, detecting an increase in temperature, shutting off the heat source, measuring the rate of temperature decrease, determining an airflow rate based on the rate of temperature decrease, and / or transmitting a temperature reading).

[0047] The microcontroller 322 may perform the thermal self-test function 330 of the fire sensing device 300 in response to a specific period of time elapsed since the previous thermal self-test function and / or in response to a command received from the monitoring device 301.

[0048] The microcontroller 322 can send a command to the heat source 319 to generate heat. The heat sensor 310 can be switched off via the variable airflow generator 316. The heat source 319 can be switched off, and the variable airflow generator 316 can be switched off. The heat sensor 310 can measure the rate of temperature decrease and / or determine the airflow rate based on the rate of temperature decrease. The fire sensing device 300 can store the measured rate of temperature decrease and / or the determined airflow rate in memory 324 and / or send the test results (e.g., the measured rate of temperature decrease and / or the determined airflow rate) to the monitoring device 301. In some examples, the fire sensing device 300 can determine whether it is operating normally based on the fire response, the measured rate of temperature decrease, and / or the determined airflow rate, and / or the monitoring device 301 can determine whether it is operating normally based on the measured rate of temperature decrease and / or the determined airflow rate. For example, monitoring device 301 may determine that fire sensing device 300 is operating normally in response to a measured rate of temperature decrease exceeding a threshold rate of temperature decrease and / or a determined airflow rate exceeding a threshold airflow rate.

[0049] Figure 4 A block diagram of a gas self-test function 440 of a fire sensing device 400 according to an embodiment of the present disclosure is shown. The block diagram of the gas self-test function 440 includes the fire sensing device 400 and a monitoring device 401. The fire sensing device 400 includes a microcontroller 422, a gas source 412, a gas sensor 414, and a variable airflow generator 416.

[0050] The microcontroller 422 may include a memory 424 and a processor 426. The memory 424 may be a non-transitory computer-readable medium storing computer-readable instructions (e.g., computer program instructions) thereon, which the processor 426 is capable of executing to test the fire sensing device 400 according to this disclosure. For example, the processor 426 may execute executable instructions stored in the memory 424 to release one or more gases using a gas source 412 and to detect one or more gases using a gas sensor 414. In some examples, the memory 424 may store threshold levels of gases sufficient to trigger a fire response from a normally functioning gas sensor 414 and / or the time period that has elapsed since a previous gas self-test function 440 (e.g., releasing gas, detecting gas, determining changes in gas levels over time, transmitting gas levels, and / or transmitting changes in gas levels over time) was performed.

[0051] The microcontroller 422 may execute the gas self-test function 440 of the fire sensing device 400 in response to a specific time period elapsed since the previous gas self-test function and / or in response to a command received from the monitoring device 401.

[0052] The microcontroller 422 can send commands to the gas source 412 to release gas. Gas can be drawn through a gas sensor 414 via a variable airflow generator 416, which measures the gas level and determines changes in the gas level over time. Once the gas level has been measured, the fire sensing device 400 can store the test results (e.g., gas level and / or changes in gas level over time) in memory 424 and / or send the test results to a monitoring device 401. The fire sensing device 400 and / or the monitoring device 401 can determine the airflow rate based on the changes in the gas level over time. In some examples, the fire sensing device 400 can determine whether it is operating normally based on the test results and / or the determined airflow rate, and / or the monitoring device 401 can determine whether it is operating normally based on the test results and / or the determined airflow rate. For example, monitoring device 401 may determine that fire sensing device 400 is operating normally in response to a fire response, detection of one or more gases, detection of one or more gas levels, determination that a gas level change over time exceeds a threshold level, and / or determination that a determined airflow rate exceeds a threshold airflow rate.

[0053] Figure 5 A fire sensing device (e.g., according to an embodiment of this disclosure) is shown. Figure 2 A graph (e.g., a curve) 550 of an exemplary optical scattering chamber (e.g., a sensor) outputting 558-1 and 558-2 indicates whether the fire sensing device 200 is operating normally. The optical scattering chamber outputs 558-1 and 558-2 may be the rate of decrease of the aerosol density level.

[0054] exist Figure 5 In the example shown, at time 552-1, a variable airflow generator (e.g., Figure 2 The variable airflow generator 216) and the adjustable particle generator (e.g., Figure 2 The adjustable particle generator 202 is de-energized (e.g., turned off). At time 552-2, the variable airflow generator and the adjustable particle generator can be energized (e.g., turned on) to initiate the smoke self-test function, as previously combined. Figure 2 As described. When powered on, an adjustable particle generator (e.g., a fan) can generate particles (e.g., aerosol particles), and the generated particles can be mixed into a controlled aerosol density level by a variable airflow generator. The variable airflow generator can cause the generated particles to move through an optical scattering chamber (e.g., Figure 2 (Optical scattering chamber 204). The optical scattering chamber can determine the airflow rate by measuring the rate of decrease of the aerosol density level after the aerosol density level has been generated.

[0055] Particles can be generated until a threshold aerosol density level (e.g., a setpoint) 556 is reached. For example, the threshold aerosol density level may be an aerosol density level sufficient to trigger a fire response (e.g., a fire threshold) 554 from a normally operating fire sensing device without saturating the optical scattering chamber. Once the threshold aerosol density level 556 is reached, the adjustable particle generator may stop generating particles at times 552-3, and the variable airflow generator may continue and / or increase the airflow, thereby causing the generated particles to move through the optical scattering chamber.

[0056] The aerosol density level measured after the adjustable particle generator has stopped can decrease over time, as illustrated in exemplary optical scattering chamber outputs 558-1 and 558-2. In exemplary optical scattering chamber output 588-1, the aerosol density level remains higher than in exemplary optical scattering chamber output 558-2 after the adjustable particle generator stops producing particles. Exemplary optical scattering chamber output 588-1 illustrates obstructed airflow through an optical scattering chamber where the optical scattering chamber is blocked and the fire sensing device is not functioning properly.

[0057] In exemplary optical scattering chamber output 588-2, the aerosol density level decreases more significantly than in exemplary optical scattering chamber output 588-1 after the adjustable particle generator stops generating particles. Exemplary optical scattering chamber output 588-2 illustrates sufficient airflow through the optical scattering chamber, which is unobstructed, and the fire sensing device is functioning normally. Once it is determined that the fire sensing device is functioning normally, a smoke self-test function is completed at time 552-4, and the variable airflow generator can be shut off.

[0058] Although specific embodiments have been illustrated and described herein, those skilled in the art will understand that any arrangement calculated to achieve the same technology may replace the specific embodiments shown. This disclosure is intended to cover any and all modifications or variations of the various embodiments of this disclosure.

[0059] It should be understood that the above description is given in an illustrative rather than restrictive manner. Combinations of the above embodiments, as well as other embodiments not specifically described herein, will be apparent to those skilled in the art upon reading the above description.

[0060] The scope of the various embodiments of this disclosure includes any other application using the structures and methods described above. Therefore, the scope of the various embodiments of this disclosure should be determined with reference to the appended claims and the full scope of their equivalents.

[0061] In the above specific embodiments, for the purpose of simplifying this disclosure, various features are combined in the example embodiments shown in the drawings. This disclosure method should not be construed as reflecting an intention to require more features than expressly recited in each claim.

[0062] Instead, as reflected in the following claims, the subject matter of the invention lies in fewer than all the features of a single disclosed embodiment. Therefore, the following claims are hereby incorporated into the detailed description, each claim being a separate embodiment in itself.

Claims

1. A self-testing fire sensing device (100, 200, 300, 400), comprising: A heat source (119), configured to generate heat at a temperature sufficient to trigger a fire response, and Thermal sensors (110, 310), said thermal sensors being configured to: The rate of temperature decrease in the self-test fire sensing device (100, 200, 300, 400) is measured. The airflow rate in the self-test fire sensing device (100, 200, 300, 400) is determined based on the measured rate of temperature decrease. as well as The self-test fire sensing devices (100, 200, 300, 400) are determined to be operating normally based on the determined airflow rate; and The determined airflow rate is used to compensate for the generation of aerosols used to perform self-testing on the self-testing fire sensing devices (100, 200, 300, 400).

2. The device of claim 1, wherein the thermal sensors (110, 310) are configured to determine whether the self-test fire sensing device (100, 200, 300, 400) is operating normally based on the determined airflow rate and the fire response.

3. The device of claim 1, wherein the thermal sensors (110, 310) are configured to determine that the self-test fire sensing device (100, 200, 300, 400) is operating normally in response to a determined airflow rate exceeding a threshold airflow rate, and to determine that the self-test fire sensing device (100, 200, 300, 400) is not operating normally in response to a determined airflow rate failing to exceed the threshold airflow rate.

4. The device of claim 3, wherein the thermal sensors (110, 310) are configured to transmit a fault notification to the monitoring devices (201, 301, 401) when it is determined that the self-test fire sensing devices (100, 200, 300, 400) are not operating normally.

5. A self-testing fire sensing device (100, 200, 300, 400), comprising: A gas source (112, 412), said gas source being configured to release one or more gases at a gas level sufficient to trigger a fire response; and Gas sensor (114, 414), the gas sensor being configured to: When the gas source (112, 412) releases the one or more gases, the gas level of the one or more gases in the self-test fire sensing device (100, 200, 300, 400) is measured. The airflow rate is determined based on the measured change in gas level over time. as well as The self-test fire sensing device (100, 200, 300, 400) is determined to be operating normally based on the airflow rate; and The determined airflow rate is used to compensate for the generation of aerosols used to perform self-testing on the self-testing fire sensing devices (100, 200, 300, 400).

6. The device of claim 5, wherein the gas sensors (114, 414) are configured to determine whether the self-test fire sensing device (100, 200, 300, 400) is operating normally based on the airflow rate and the fire response.

7. The device of claim 5, wherein the gas sensor (114, 414) is configured to determine whether the self-test fire sensing device (100, 200, 300, 400) is operating normally in response to the detection of the one or more gases.

8. The device of claim 5, wherein the gas sensors (114, 414) are configured to determine that the self-test fire sensing device (100, 200, 300, 400) is operating normally in response to a determined airflow rate exceeding a threshold airflow rate, and to determine that the self-test fire sensing device (100, 200, 300, 400) is not operating normally in response to a determined airflow rate failing to exceed the threshold airflow rate.

9. The device of claim 8, wherein the gas sensor (114, 414) is configured to transmit a fault notification to the monitoring device (201, 301, 401) when it is determined that the self-test fire sensing device (100, 200, 300, 400) is not operating normally.

10. The apparatus of claim 5, wherein the gas source (112, 412) generates the one or more gases via combustion.

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