Calibration of heating elements in fire sensing devices

Abstract

Devices, methods, and systems for calibrating a heating element in a fire sensing device are described herein. An apparatus includes a heating element, a reservoir containing a liquid or wax, a variable gas flow generator, and a controller configured to receive a characteristic of the heating element and apply a calibrated electrical heating input to the heating element based on the characteristic of the heating element. A heating element configured to heat the liquid or wax to generate a specific amount of aerosol or gas in response to the calibrated electrical heating input; and the variable gas flow generator is configured to move the specific amount of aerosol or gas through the fire sensing device and to return the fire sensing device to a state prior to generating the specific amount of aerosol or gas.

Description

Technical Field

[0001] The present disclosure generally relates to apparatus, methods, and systems for calibrating heating elements in fire sensing devices. Background Art

[0002] Large facilities (e.g., buildings), such as commercial facilities, office buildings, hospitals, etc., may have fire alarm systems that can be triggered during an emergency (e.g., a 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) throughout the facility (e.g., on different floors and / or in different rooms of the facility) that can sense a fire occurring in the facility and provide notification of the fire to occupants of the facility via an alarm.

[0003] Maintenance of fire alarm systems may include mandatory periodic testing of fire sensing devices in accordance with operating procedures in an attempt to ensure that the fire sensing devices are functioning properly. However, since testing can only be done periodically, there is a risk that a faulty fire sensing device may not be discovered quickly or that all fire sensing devices in the fire alarm system will not be tested.

[0004] Typical testing involves a maintenance engineer using a pressurized aerosol to force synthetic smoke into the chamber of the fire sensing device, which saturates the chamber. In some examples, the maintenance engineer may also use a heat gun to increase the temperature of a thermal sensor in the fire sensing device and / or a gas generator to exhaust carbon monoxide (CO) gas into the fire sensing device. These tests may not accurately mimic the characteristics of a fire, and therefore, these tests may not accurately determine the ability of the fire sensing device to detect an actual fire.

[0005] Moreover, this process of manually testing each fire sensing device can be time consuming, expensive, and disruptive to business. For example, maintenance engineers are often required to access fire sensing devices located in areas occupied by building users or in generally inaccessible parts of a building (e.g., elevator shafts, high ceilings, ceiling spaces, etc.). As a result, it may take several days and several visits for a maintenance engineer to complete testing of the fire sensing devices, especially in large locations. Additionally, there are often many fire sensing devices that are never tested due to access issues.

[0006] Over time, the fire sensing device may become dirty, for example, with dust and debris, and become clogged. A clogged fire sensing device may prevent air and / or particles from passing through the fire sensing device to a sensor in the fire sensing device, which may otherwise render the fire sensing device unable to detect smoke, fire, and / or carbon monoxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A block diagram illustrating a self-test function of a fire sensing device according to an embodiment of the present disclosure.

[0008] Figure 2 An example of a self-testing fire sensing device according to an embodiment of the present disclosure is shown.

[0009] Figure 3 An exemplary circuit for calibrating a heating element of a fire sensing device according to an embodiment of the present disclosure is shown.

[0010] Figure 4 An exemplary circuit for calibrating a heating element of a fire sensing device according to an embodiment of the present disclosure is shown.

[0011] Figure 5 A block diagram illustrating the self-test functionality of a system according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0012] Devices, methods, and systems for calibrating a heating element in a fire sensing device are described herein. A device includes a heating element, a reservoir containing a liquid or wax, a variable airflow generator, and a controller configured to receive a characteristic of the heating element and apply a calibrated electrical heating input to the heating element based on the characteristic of the heating element. The heating element is configured to heat the liquid and / or wax to generate a specific amount of aerosol and / or gas in response to the calibrated electrical heating input; and the variable airflow generator is configured to: move the specific amount of aerosol and / or gas through the self-test fire sensing device, and return the self-test fire sensing device to a state before the specific amount of aerosol and / or gas was generated.

[0013] Compared to previous fire sensing devices, in which maintenance engineers must manually test each fire sensing device in a facility (e.g., using a pressurized aerosol, a heat gun, a gas generator, or some combination thereof) to determine whether maintenance of the device is required, the fire sensing device according to the present disclosure can self-test. Therefore, the fire sensing device according to the present disclosure can spend significantly less maintenance time to test to determine whether maintenance is required, can be tested continuously and / or on demand, and can more accurately determine the ability of the fire sensing device to detect actual fires. Therefore, the self-testing fire sensing device can have an extended service life and be replaced less frequently, thereby having a positive impact on the environment.

[0014] Additionally, in some fire sensing devices (e.g., self-testing fire sensing devices), wax and / or liquid are heated (e.g., using a heating element) to a specific temperature and / or for a specific amount of time to generate an aerosol for testing the functionality of the device. However, in some cases, due to manufacturing variability of the fire sensing device, such as variability in the resistance of the heating element, the number of coils of the heating element, the length of the heating element, the diameter of the heating element, and / or the type of wire of the heating element, as well as other manufacturing variability, this may generate too little aerosol or too much aerosol. However, a fire sensing device according to the present disclosure may account for these manufacturing variability and generate a more controlled amount of aerosol and / or gas by determining and / or using the characteristics of the heating element to determine how much power to apply to the heating element to heat the wax and / or liquid to generate the desired amount of aerosol and / or gas, thereby generating a test fire condition within the fire sensing device. Thus, fire sensing devices according to the present disclosure may perform more accurate self-tests, properly exhaust aerosols and / or gases after self-testing, use less liquid and / or wax to generate aerosols and / or gases, have lower visible contamination rates per test, reduce wax contamination accumulation rates, compensate for manufacturing variations, and / or have better tolerances than previous devices.

[0015] In the following Detailed Description, reference is made to the accompanying drawings which form part of the present Detailed Description. The drawings show, by way of illustration, the manner in which one or more embodiments of the present disclosure may be practiced.

[0016] These embodiments are described in sufficient detail to enable one of ordinary skill in the art to practice one or more embodiments of the present disclosure. 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 the present disclosure.

[0017] It should be understood that the elements shown in the various embodiments herein may be added, exchanged, combined and / or eliminated to provide multiple additional embodiments of the present disclosure. The proportions and relative sizes of the elements provided in the drawings are intended to illustrate embodiments of the present disclosure and should not be limiting.

[0018] The drawings herein follow the following numbering convention: one or more first digits correspond to the drawing number, and the remaining digits identify the element or component in the drawing. Similar elements or components between different drawings may be identified by using similar numerals. For example, 102 may be in FIG. Figure 1 Reference component "02" in the example, and similar components can be found in Figure 2 Cited as 202.

[0019] As used herein, "a" or "a number of" things may refer to one or more such things, and "a plurality" of things may refer to more than one such thing. For example, "a number of components" may refer to one or more components, and "a plurality of components" may refer to more than one component.

[0020] Figure 1 A block diagram of a self-test function of a fire sensing device 100 (e.g., the fire sensing device 100 may be a self-testing fire sensing device) according to an embodiment of the present disclosure is shown. The fire sensing device 100 includes a controller (e.g., a microcontroller) 122, an adjustable particle generator 102, an optical scattering chamber 104, and a variable airflow generator 116.

[0021] The controller 122 may include a memory 124 and a processor 126. The memory 124 may be any type of storage medium that can be accessed by the processor 126 to perform various examples of the present disclosure. For example, the memory 124 may be a non-transitory computer-readable medium having computer-readable instructions (e.g., computer program instructions) stored thereon, which instructions can be executed by the processor 126 to calibrate the heating element 108 of the fire sensing device 100 according to the present disclosure. For example, the processor 126 may execute the executable instructions stored in the memory 124 to receive and / or determine a characteristic (such as resistance) of the heating element 108, and apply a calibrated electrical heating input to the heating element 108 based on the characteristic of the heating element 108. The calibrated electrical heating input may be, for example, an electric current.

[0022] In a single embodiment, the controller 122 may apply a calibrated electrical heating input to the heating element 108 of the adjustable particle generator 102 to heat the liquid or wax, thereby generating a specific amount of aerosol and / or gas, such as, for example, a specific amount of aerosol particles. The aerosol particles can be solid particles or liquid particles in a gas. The particles generated by the adjustable particle generator 102 can be moved (e.g., drawn) through the optical scattering chamber 104 by the variable airflow generator 116, generating an air flow and producing a controlled aerosol density level. The specific amount of aerosol and / or gas (e.g., the aerosol density level) can be sufficient to trigger a fire response from the fire sensing device 100 without saturating the optical scattering chamber 104. As Figure 1 As shown, the optical scattering chamber 104 may include a transmitter light emitting diode (LED) 105 and a receiver photodiode 106 to measure aerosol density levels.

[0023] In some examples, the controller 122 can determine the characteristics of the heating element 108 by applying a monitoring electrical input to the heating element 108 before applying the calibrated electrical heating input to the heating element 108 and measuring the electrical output from the heating element 108 in response to applying the monitoring electrical input. For example, the monitoring electrical input can be a monitoring current. The characteristics of the heating element 108 can be determined based on the monitoring electrical input and the measured electrical output from the heating element 108 and used to determine the calibrated electrical heating input.

[0024] Figure 2 An example of a self-testing fire sensing device 200 according to an embodiment of the present disclosure is shown. The fire sensing device 200 may be, but is not limited to, a fire detector and / or a smoke detector of a fire control system.

[0025] The fire sensing device 200 can sense a fire occurring in a facility and trigger a fire response to provide notification of the fire to the occupants of the facility. The fire response can include, for example, a visual and / or audio alarm. The fire response can also notify emergency services (e.g., fire department, police department, etc.). In some examples, multiple fire sensing devices can be located throughout the facility (e.g., on different floors and / or in different rooms of the facility).

[0026] The fire sensing device 200 may automatically or upon command perform one or more tests contained within the fire sensing device 200. The one or more tests may determine whether the fire sensing device 200 is operating properly and / or requires maintenance.

[0027] like Figure 2 As shown, the fire sensing device 200 may include an adjustable particle generator 202, an optical scattering chamber 204 including a transmitter light emitting diode (LED) 205 and a receiver photodiode 206, a heating element 208, a reservoir 212, and a variable airflow generator 216. In some examples, the fire sensing device 200 may also include a controller including a memory and / or a processor, as described above in conjunction with Figure 1 described.

[0028] As mentioned above Figure 1As described, the heating element 208 of the adjustable particle generator 202 can heat the liquid and / or wax contained in the reservoir 212 to generate aerosol particles, which can be mixed into a controlled aerosol density level by the variable airflow generator 216. The heating element 208 can be, for example, a wire including a resistance wire. In some examples, the heating element 208 can be a wire in the shape of a coil. The current flowing through the wire can be used to control the temperature of the heating element 208 and further control the number of particles generated by the adjustable particle generator 202. The heating element 208 can contact with the liquid and / or wax to heat the liquid and / or wax, thereby generating airborne particles to simulate smoke from a fire. These particles can measure a diameter of about 1 micron and / or the particles can be within the sensitivity range of the optical scattering chamber 204.

[0029] The heating element 208 can have a variety of different characteristics, including resistance, number of coil turns, number of coils, length, diameter, material and / or wire type, and other characteristics, which may vary due to variability in the manufacturing of the heating element 208. Such manufacturing variability may cause the adjustable particle generator 202 to generate too little aerosol or too much aerosol. Too much aerosol may produce odor and / or noticeable smoke, which may cause anxiety to indoor residents, while too little aerosol may not be enough to generate a test fire condition (e.g., trigger a fire response) during testing of the fire sensing device 200. The fire sensing device 200 can generate a more controlled amount of aerosol by determining the resistance of its heating element 208 to determine how much power to apply to the heating element 208 to heat the wax and / or liquid to generate a specific amount of aerosol, thereby generating a test fire condition within the fire sensing device 200. In some examples, the resistance of the heating element 208 can be determined before each self-test process is run on the fire sensing device 200. For example, the resistance can be determined before the heating element 208 is heated.

[0030] For example, a monitoring electrical input may be applied to the heating element 208. In response to applying the monitoring electrical input to the heating element 208, an electrical output from the heating element 208 may be measured. The monitoring electrical input and / or the electrical output may be, for example, a voltage or a current. The resistance of the heating element 208 may be determined based on the applied monitoring electrical input and the measured electrical output. For example, the resistance of the heating element may be determined by dividing the electrical output by the monitoring electrical input. Knowing the resistance of the heating element may enable the fire sensing device 200 to generate a known amount of power, which in turn generates a known amount of heat, and thus generates a known amount of aerosol.

[0031] For example, a calibrated electrical heating input may be determined based on the determined resistance of the heating element 208 and applied to the heating element 208 to heat the liquid and / or wax to generate a specific amount of aerosol and / or gas within the fire sensing device 200. In various embodiments, the calibrated electrical heating input may be a current or voltage, which may be determined based on the determined resistance of the heating element 208 and / or the power output of the heating element 208 to continuously heat the heating element 208 to generate a specific amount of aerosol and / or gas. Applying the calibrated electrical heating input to the heating element 208 to heat the liquid and / or wax to generate a specific amount of aerosol and / or gas may be performed as part of a self-test of the fire sensing device 200 to determine whether the fire sensing device 200 is operating properly or requires maintenance. As part of a self-test, the heating element 208 can heat the liquid and / or wax to produce an aerosol density level sufficient to trigger a fire response from a normally operating fire sensing device without saturating the optical scattering chamber 204 and / or an aerosol density level sufficient to test a fault condition without triggering a fire response or saturating the optical scattering chamber 204.

[0032] The variable airflow generator 216 can control the airflow through the fire sensing device 200 including the optical scattering chamber 204. For example, the variable airflow generator 216 can move the gas and / or the generated aerosol from the first end of the fire sensing device 200 to the second end of the fire sensing device 200. For example, the variable airflow generator 216 can generate an airflow to move the generated aerosol through the optical scattering chamber 204. In some examples, the variable airflow generator 216 can be a fan. The variable airflow generator 216 can be activated in response to the activation of the adjustable particle generator 202. The variable airflow generator 216 can be stopped in response to the stop of the adjustable particle generator 202, and / or the variable airflow generator 216 can be stopped for a specific period of time after the adjustable particle generator 202 has stopped.

[0033] In various embodiments, once the aerosol density level has reached a level sufficient to trigger a fire response, the adjustable particle generator 216 can be turned off and the variable airflow generator 216 can increase the rate of airflow through the optical scattering chamber 204. The variable airflow generator 216 can increase the rate of airflow through the optical scattering chamber 204 to reduce the aerosol density level back to a baseline level. The baseline level can be the initial level of the optical scattering chamber 204 before the adjustable particle generator 216 generates particles. For example, the variable airflow generator 216 can remove aerosol and / or gas from the optical scattering chamber 204 after the measured aerosol density level reaches a level sufficient to trigger a fire response. If the fire sensing device 200 is not blocked or covered, the airflow from the external environment through the optical scattering chamber 204 will cause the aerosol density level to decrease.

[0034] The optical scatter chamber 204 may sense the external environment as the damper opening in the fire sensing device 200 allows air and / or smoke from the fire to flow through the fire sensing device 200. The optical scatter chamber 204 may measure the aerosol density level of the generated aerosol.

[0035] In various embodiments, the measured aerosol density level can be used to determine whether the fire sensing device 200 is operating properly. For example, it can be determined that the fire sensing device 200 is operating properly based on comparing the measured aerosol density level to a threshold aerosol density level, which can be an aerosol density level sufficient to trigger a fire response from the fire sensing device 200 without saturating the light scattering chamber 204. If the fire sensing device 200 does not reach the threshold aerosol density level, the device can generate a message. The fire sensing device 200 can send the message to, for example, a monitoring device and / or a mobile device. As an additional example, the fire sensing device 200 can include a user interface that can display a message.

[0036] Figure 3 A method for calibrating a fire sensing device (e.g., Figure 1 The fire sensing device 100 and / or Figure 2 A heating element (e.g., Figure 1 The heating element 108 and / or Figure 2 For example, the circuit 320 may be a low voltage direct current (DC) driver and may include the circuit 320 described above in conjunction with the Figure 1 The controller 122 is described as being in and / or operated thereby.

[0037] Circuit 320 may be switched on at switch 334. Switch 334 may be a transistor including a metal oxide semiconductor field effect transistor (MOSFET). Circuit 320 may be switched on in response to the fire sensing device performing a self-test or receiving a command to determine the resistance of heating element 325.

[0038] Circuit 320 may be used to determine (e.g., calculate) the resistance of heating element 325 by monitoring an electrical input (e.g., monitoring voltage or monitoring current) via a power supply unit 323 input and receiving an electrical output (e.g., output voltage or output current) from a divider (e.g., a voltage divider) at processor 326, which may correspond to a combination of Figure 1 The processor 126. The divider may include two series connected electrical impedances. Figure 3 As shown, the electrical impedance may be the resistance of resistor 336 and the resistance of heating element 325 .

[0039] The voltage 338 across the resistance of the resistor 336 may be converted from analog to digital via the analog-to-digital converter 332 of the processor 326, and the voltage 327 across the resistance of the heating element 325 may be converted from analog to digital via the analog-to-digital converter 328 of the processor 326. The resistance of the heating element 325 may be calculated by the processor 326 using the following formula 1:

[0040]

[0041] Where Rx is the resistance of heating element 325 , R1 is the resistance of resistor 336 , V1 is voltage 327 , and V2 is voltage 338 .

[0042] A calibrated electrical heating input from the power supply unit 323 may be applied to the heating element to heat the liquid and / or wax to generate a specific amount of aerosol and / or gas based on the resistance of the heating element 325 using the following Equation 2:

[0043]

[0044] Where Vpsu is the calibrated electrical heating input from the power supply unit 323, P is the constant power, and R x is the resistance of the heating element 325 .

[0045] Equation 1 and Equation 2 can be combined to produce the following Equation 3:

[0046]

[0047] Where Vpsu is the calibrated electrical heating input from the power supply unit 323, P is the constant power, R1 is the resistance of resistor 336, ADC1 is the digital conversion of voltage 327, and ADC2 is the digital conversion of voltage 338.

[0048] Figure 4 A method for calibrating a fire sensing device (e.g., Figure 1 The fire sensing device 100 and / or Figure 2 A heating element (e.g., Figure 1 The heating element 108 and / or Figure 2 For example, the circuit 440 may be a high voltage driver having a modulated power supply unit 423 and may include the circuit 440 described above in conjunction with the Figure 1 The controller 122 is described as being in and / or operated thereby.

[0049] The circuit 440 may be switched on at the switch 449. The switch 449 may be a transistor including a MOSFET. The circuit 440 may be switched on in response to the fire sensing device performing a self-test or receiving a command to determine the resistance of the heating element 425.

[0050] Circuit 440 may be used to determine (e.g., calculate) the resistance of heating element 425 by monitoring an electrical input (e.g., monitoring voltage or monitoring current) via power supply unit 423 input and receiving an electrical output (e.g., output voltage or output current) from a divider (e.g., voltage divider) at processor 426, which may correspond to a combination of Figure 1 The processor 126. The divider may include two series connected electrical impedances. Figure 4 As shown, the electrical impedance may be the resistance of the heating element 425 and the resistance of the resistor 436 , followed by the transistor 434 .

[0051] The voltage 438 across the resistance of resistor 448 and the capacitance of capacitor 447 may be converted from analog to digital via the analog-to-digital converter 432 of the processor 426, and the voltage 427 across the resistance of resistor 444 and the capacitance of capacitor 445 may be converted from analog to digital via the analog-to-digital converter 428 of the processor 426. Before measuring the voltage 438 across the resistance of resistor 448 and the capacitance of capacitor 447, the resistance of resistor 446 may reduce the voltage 438, and before measuring the voltage 427 across the resistance of resistor 444 and the capacitance of capacitor 445, the resistance of resistor 442 may reduce the voltage 427.

[0052] The resistance of the heating element 425 may be calculated by the processor 426 using the following equation 4:

[0053]

[0054] Where Rx is the resistance of heating element 425 , V1 is the voltage 427 , R2 is the resistance of resistor 442 , R3 is the resistance of resistor 444 , V2 is the voltage 438 , R4 is the resistance of resistor 446 , and R5 is the resistance of resistor 448 .

[0055] Pulse width modulation (PWM) of the duty cycle may be a calibrated electrical heating input and may be applied to the heating element to heat the liquid and / or wax to generate a specific amount of aerosol and / or gas based on the resistance of the heating element 425 using the following Equation 5:

[0056]

[0057] Where Dpwm is the pulse width modulation of the duty cycle, P is the constant power, Vpsu is the calibrated electrical heating input from the power supply unit 423 , and Rx is the resistance of the heating element 425 .

[0058] Equation 4 and Equation 5 can be combined to produce the following Equation 6:

[0059]

[0060] Wherein Dpwm is the pulse width modulation of the duty cycle, P is constant power, Vpsu is the calibrated electrical heating input from the power supply unit 423, ADC1 is the digital conversion of the voltage 427, ADC2 is the digital conversion of the voltage 438, R2 is the resistance of resistor 442, R3 is the resistance of resistor 444, R4 is the resistance of resistor 446, and R5 is the resistance of resistor 448.

[0061] Figure 5 1 is a block diagram showing the self-test function of a system 550 according to an embodiment of the present disclosure. The system 550 may include a fire sensing device 500, a monitoring device 554, and a computing device 556. The fire sensing device 500 may be, for example, a combination of the above-mentioned Figure 1 and Figure 2 The fire sensing device 100 and / or 200.

[0062] The fire sensing device 500 may include a user interface 552. The user interface 552 may be a graphical user interface (GUI) that may provide information to and / or receive information from a user, a monitoring device 554, and / or a computing device 556. In some examples, the user interface 552 may display a message. For example, the user interface 552 may display a message in response to the fire sensing device 500 failing to determine that a heating element (e.g., Figure 1 The heating element 108 and / or Figure 2 The message may be displayed based on the resistance or other characteristics of the heating element 208 in the display.

[0063] The monitoring device 554 may be a cloud computing device of a control panel, a fire detection control system, and / or a fire alarm system. The monitoring device 554 may be configured to send commands and / or messages to and / or receive commands and / or messages from the fire sensing device 500 via a wired or wireless network. For example, the monitoring device 554 may transmit a characteristic of a heating element within the fire sensing device 500. For example, the characteristic may be the resistance of the heating element measured during the manufacture of the fire sensing device 500.

[0064] The monitoring device 554 may receive messages from a plurality of fire sensing devices similar to the fire sensing device 500. For example, the monitoring device 554 may receive messages from each of the plurality of fire sensing devices similar to the fire sensing device 500 and generate a ledger of characteristics of the heating element of each respective fire sensing device.

[0065] In various embodiments, the monitoring device 554 may include a user interface 555. The user interface 555 may be a GUI that may provide information to and / or receive information from a user and / or the fire sensing device 500. The user interface 555 may display messages and / or data received from the fire sensing device 500. For example, the user interface 555 may display a message that the fire sensing device 500 needs a new heating element, wax, and / or liquid in response to the fire sensing device 500 failing to generate sufficient aerosol and / or gas.

[0066] In various embodiments, the computing device 556 may receive messages from the fire sensing device 500 and / or the monitoring device 554 via a wired or wireless network. The computing device 556 may be a personal laptop computer, a desktop computer, a mobile device (such as a smart phone, a tablet computer, a wrist-worn device), and / or redundant combinations thereof, as well as other types of computing devices.

[0067] In some examples, the computing device 556 may include a user interface 557 to display messages from the monitoring device 554 and / or the fire sensing device 500. For example, the user interface 557 may display messages. The user interface 557 may be a GUI that may provide information to and / or receive information from a user, the monitoring device 554, and / or the fire sensing device 500.

[0068] The network described herein may be a network relationship through which the fire sensing device 500, the monitoring device 554, and / or the computing device 556 can communicate with each other. Examples of such network relationships may include a distributed computing environment (e.g., a cloud computing environment), a wide area network (WAN) such as the Internet, a local area network (LAN), a personal area network (PAN), a campus area network (CAN), or a metropolitan area network (MAN), as well as other types of network relationships. For example, the network may include a plurality of servers that receive information from the fire sensing device 500, the monitoring device 554, and the computing device 556 via a wired or wireless network and transmit information to the fire sensing device, the monitoring device, and the computing device.

[0069] As used herein, a "network" may provide a communication system that directly or indirectly links two or more computers and / or peripheral devices and allows the monitoring device 554 and / or computing device 556 to access data and / or resources on the fire sensing device 500 or vice versa. A network may allow a user to share resources on their own system with other network users and access information on a system located in a central location or a system located in a remote location. For example, a network may connect multiple computing devices together to form a distributed control network (e.g., a cloud).

[0070] The network may provide connectivity to the Internet and / or to the networks of other entities (e.g., organizations, institutions, etc.). Users may interact with network-enabled software applications to make network requests, such as to obtain data. Applications may also communicate with network management software, which may interact with network hardware to transfer information between devices on the network.

[0071] Although specific implementations have been illustrated and described herein, those of ordinary skill in the art will appreciate that any arrangement calculated to achieve the same technique may be substituted for the specific implementations shown. This disclosure is intended to cover any and all modifications or variations of various implementations of the present disclosure.

[0072] It should be understood that the above description is given in an illustrative rather than limiting manner.By reading the above description, combinations of the above embodiments, as well as other embodiments not specifically described herein, will be apparent to those skilled in the art.

[0073] The scope of the various embodiments of the present disclosure includes any other applications using the above-described structures and methods.The scope of the various embodiments of the present disclosure should therefore be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

[0074] In the above detailed description, various features are grouped together in the exemplary embodiments shown in the drawings for the purpose of simplifying the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the present disclosure require more features than are expressly recited in each claim.

[0075] Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment.Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

Claims

1. A self-testing fire sensing device (100, 200, 500), comprising: Heating element (108, 208); a reservoir (212) containing a liquid or wax; a variable airflow generator (216); and A controller (122), the controller being configured to: receiving characteristics of the heating element (108, 208); and applying a calibrated electrical heating input to the heating element (108, 208) based on the characteristic of the heating element (108, 208); wherein the heating element (108, 208) is configured to heat the liquid or wax to generate a specific amount of aerosol or gas in response to the calibrated electrical heating input; and The variable airflow generator (216) is configured as follows: moving the specified amount of aerosol or gas through the self-testing fire sensing device (100, 200, 500); and Return the self-testing fire sensing device (100, 200, 500) to The state before the specific amount of aerosol or gas is generated.

2. The apparatus of claim 1, wherein the heating element (108, 208) is a wire, and wherein the characteristic of the heating element (108, 208) is a material of the wire, a length of the wire, or a diameter of the wire.

3. The apparatus of claim 1, wherein the characteristic of the heating element (108, 208) is a resistance of the heating element (108, 208).

4. The apparatus of claim 1, wherein the calibrated electrical heating input is a voltage.

5. The apparatus of claim 1, wherein the heating element (108, 208) is a wire in the shape of a coil.

6. The apparatus of claim 1, wherein the controller (122) is configured to: applying a monitoring electrical input to the heating element (108, 208) prior to applying the calibrated electrical heating input to the heating element (108, 208); and In response to applying the monitoring electrical input, an electrical output from the heating element (108, 208) is measured.

7. The apparatus of claim 6, wherein the controller (122) is configured to determine the characteristic of the heating element (108, 208) based on a measured electrical output from the heating element (108, 208).

8. The apparatus of claim 6, wherein the measured electrical output from the heating element (108, 208) is a voltage.

9. The apparatus of claim 1, wherein the controller (122) is configured to: measuring an aerosol density level of the specific amount of aerosol via an optical scattering chamber (104, 204); comparing the measured aerosol density level to a threshold aerosol density level; and In response to comparing the measured aerosol density level to the threshold aerosol density level, it is determined whether the self-test fire sensing device (100, 200, 500) is functioning properly.

10. The device of claim 9, wherein the threshold aerosol density level is sufficient to trigger a fire response from the self-testing fire sensing device (100, 200, 500) without saturating the optical scattering chamber (104, 204).

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