Early fire detection based on VOC concentration and passenger cabin for a passenger aircraft

Abstract

A fire alarm system (20) comprising a plurality of sensor modules (22) with an energy module (28) for operating energy, a VOC sensor (34) which supplies a sensor signal (36) for a VOC concentration (38), an evaluation module (30) for supplying sensor data (46), and a communication module (32) for transmitting these to a central module (24), contains the central modules (24) for determining and providing fire characteristic values ​​(48) on the basis of the VOC concentrations (38) in the sensor data (46). A passenger cabin (4) for a passenger aircraft (2) contains the fire alarm system (20) and storage compartments (12) with the sensor modules (22). In a method for monitoring an object (120) for fires using the fire alarm system (20), the sensor modules (22) are mounted there, the energy module (28) supplies the operating energy and the VOC sensor (34) the sensor signal (36), the evaluation module (30) pre-processes this into sensor data (46), the communication module (32) transmits this to the central module (24), the central module determines the fire characteristic values ​​(48) based on the sensor data (46) and VOC concentrations (38) and provides these, and the object (120) is monitored for fires based on the fire characteristic values ​​(48).

Description

[0001] The invention relates to the monitoring of an object for fire using a fire alarm system.

[0002] From DE 10 2021 112 279 A1 a system for fire and / or smoke detection in an aircraft is known, in particular in a cargo hold of an aircraft, comprising: a plurality of temperature detection units, each having at least one temperature sensor and a radio transmission unit, a plurality of radio transmitters for receiving and forwarding signals from the radio transmission units, and at least one radio reader for receiving and forwarding signals from the radio transmitters, wherein the at least one radio reader is connected to an on-board voltage supply of the aircraft and is connected to a computing unit, in particular to an on-board computer of the aircraft.

[0003] DE 10 2008 057 086 A1 discloses a gas sensor system that detects human activity and presence in an enclosed space based on the measurement of, for example, oxygen or volatile organic hydrocarbons. The gas sensor system can be installed with the necessary safety sensors.

[0004] From US 2022 / 0 058 928 A1, embodiments of a sensor device, method and system are known; these use a plurality of environmental sensors as a single monitoring and warning mechanism that can provide a profile of all pollutants in the form of various gases and particles in the atmosphere, quantified in the form of relative concentrations.

[0005] From EP 4 067 900 A1, a system configured for installation in an airflow duct is known; this system comprises a metal surface configured to convert liquid-phase contaminants in the airflow duct of a vehicle into vapor-phase contaminants; and a sensor configured to detect the vapor-phase contaminant in the airflow duct; and a communication circuit configured to transmit data indicative of the detected concentrations of the vapor-phase contaminants.

[0006] From US 2021 / 0 003 310 A1 a system and a method are known for monitoring and controlling air quality in enclosed spaces, which provide an innovative closed loop (i.e. in-line feedback in real time) for air management and use learning and predictive capabilities to ensure effective air purification and, if necessary, reliable alarming.

[0007] The object of the present invention is to propose improvements with regard to the monitoring of an object for a fire by means of a fire alarm system.

[0008] The object is achieved by a fire alarm system according to patent claim 1. Preferred or advantageous embodiments of the invention and other categories of invention emerge from the further claims, the following description and the attached figures.

[0009] The fire alarm system is designed to monitor a building for fires. The fire alarm system contains several sensor modules. Each sensor module contains an energy module, a VOC sensor, an evaluation module, and a communication module.

[0010] The energy module is designed to provide or supply energy for the operation of the sensor module.

[0011] The VOC sensor is designed to provide or deliver a sensor signal during operation of the fire alarm system or sensor module. The sensor signal is correlated with a current VOC concentration (volatile organic compounds, volatile organic or carbon compounds) at the location of the sensor module. This also records the VOC concentration in an environment around the sensor module where it can be assumed that a respective concentration equilibrium is established with sufficient accuracy. This applies, for example, if the sensor module is located in a comparatively small space, e.g. a storage or baggage compartment of a passenger aircraft. The concentration is then always assumed to be the same throughout the entire (free air) space of the storage compartment.

[0012] The evaluation module is designed to at least pre-process the sensor signal into sensor data, whereby the sensor data are correlated with the VOC concentrations measured by the VOC sensor (current and / or historical, depending on the pre-processing).

[0013] The communication module is configured to transmit at least the sensor data to the central module. "At least transmit" means that other data may also be optionally transmitted and / or data transmitted by the central module may also be optionally received. In particular, the communication module is configured for wireless communication. It operates or communicates, in particular, via BTLE (Bluetooth Low Energy), Wi-Fi (Wireless Fidelity), or similar. In particular, the communication module also transmits control commands from the central module to the sensor modules. In particular, device statuses, error messages, etc., are also communicated via this communication.

[0014] The fire alarm system also includes at least one central module. These modules are configured to determine and provide a fire characteristic value for a particular environment of the respective sensor module based on the received sensor data and the correlated VOC concentrations provided by the sensor modules.

[0015] In particular, the evaluation module and / or the central module uses AI (artificial intelligence) methods for the (pre-)processing of the sensor signals / sensor data.

[0016] In contrast to particle-based smoke detection or optical-based fire detection, VOC concentration monitoring allows for very early detection of situations surrounding fires. VOC concentrations rise, for example, when electrical components / batteries, etc., in an electrical device become significantly heated / overheated without a fire / smoke having yet developed. The components and surrounding elements (plastics, paints, etc.) release VOCs. Thanks to a fire alarm system, it is therefore possible to detect situations that could potentially lead to a fire in the future (with further heating) based on VOCs, even before a fire has broken out. This way, even a potential fire or fire hazard can be detected, and appropriate action can be taken.

[0017] In the simplest case, the fire characteristic value is, for example, a digital yes / no value, whether heating / a potentially developing fire is detected (VOC concentration above a threshold value) or not (below the threshold value).

[0018] In particular, upon detection of a potential or actual fire ("Yes value"), a silent alarm can be triggered, so that, for example, fire prevention / firefighting personnel are notified of the alarm, but not other persons, such as passengers / customers, etc. This way, a fire can be prevented or extinguished early without causing panic.

[0019] The fire alarm system therefore allows a building equipped with the system to be monitored for fire. "Fire monitoring" even means that a "fire hazard"—that is, a fire that has previously only been imminent—can be monitored as a "fire." The term "fire" is therefore to be broadly understood here, including a "fire hazard" where no actual fire is yet present, but where one could realistically occur.

[0020] In a preferred embodiment, the sensor module contains a sensing element for a current temperature at the location of the sensor module. Alternatively or additionally, it contains a sensing element for a current pressure at the location of the sensor module. Alternatively or additionally, it contains a sensing element for a current volume of a space to be sensed using the sensor module, in or on which the sensor module—sensing the VOC concentration in the space—is installed during operation.

[0021] The "detection element" is to be understood broadly here and can be a sensor element that detects the relevant quantities using sensors or measurements. However, it can also be an input element / interface where, for example, a spatial volume of a corresponding size can be entered or programmed. The volume of the space can, for example, be empty volume, but a correspondingly current free airspace volume (i.e., not occupied or enclosed by objects) can also be addressed, for example, if the free airspace volume in the room changes due to objects being stored in the room. An example would be a storage compartment in the passenger cabin of a passenger aircraft, which has an empty space. However, the free airspace in the volume changes depending on the volume of luggage / clothing, etc. brought in.

[0022] By appropriately recording and subsequently processing temperature, pressure and volume in the fire alarm system when determining the fire characteristic value, the accuracy of the fire alarm system with regard to determining the fire characteristic value can be improved.

[0023] In a preferred embodiment, the fire characteristic is correlated with a time course, i.e., a time course, in particular an increase, of the VOC concentration. In other words, the course of the VOC concentration is recorded over time. In particular, a steep / sudden increase in VOC concentrations is an indication of sudden warming / heating and thus presumably a technical defect in an electrical device. For example, a defect in an electrical component can manifest itself in its heating, which in the future - with further heating - could lead to a fire. However, the heating of materials / electronics, etc. can already be recorded based on the increase in VOC concentration, thus generating a corresponding fire characteristic. Thus, the outbreak of a fire can possibly even be prevented or a fire can be detected very early.

[0024] A corresponding time course of the increase is a particularly meaningful value for determining meaningful fire characteristics.

[0025] In a preferred embodiment, the energy module contains a connection for a power supply line. Alternatively or additionally, it contains a battery. Alternatively or additionally, it contains an energy harvesting module. The battery is, in particular, a rechargeable battery / accumulator. The energy harvesting module is provided, in particular, in conjunction with a battery to relieve the burden of its discharge or, if necessary, even to recharge a rechargeable battery. An energy harvesting module contains, for example, mechanical piezo generators, solar cells, Peltier elements, or other conventional means for generating energy from the environment / surroundings, i.e., which are used to "harvest" energy from the environment.

[0026] With regard to this embodiment, the central module and / or the evaluation module is also configured, for example, to determine and exchange the current charge state of a battery or the state of the energy harvesting module, etc.

[0027] Each of the options - supply line, battery and energy harvesting - for supplying the sensor module with energy has typical advantages and disadvantages, so that the most cost-effective energy supply can be selected depending on the application.

[0028] In a preferred embodiment, the central module contains a built-in module, e.g., a network card, for a main computer system of a property to be monitored by the fire alarm system. The central module also contains a partial implementation for the main computer system. The main computer system is, for example, an on-board computer in a passenger cabin in a passenger aircraft. In other words, the central module has a distributed structure: on the one hand, with the physical / real built-in module, and on the other hand, with the program-related partial implementation for the main computer system. The partial implementation is, for example, a software implementation of the activities to be performed by the central module. The built-in module is the corresponding hardware component for physically connecting the fire alarm system to the main computer system.

[0029] This means the fire alarm system can be easily integrated into an object to be monitored.

[0030] In a preferred embodiment, the central module and / or the evaluation module contain a neural accelerator. This enables these modules to achieve particularly high computing or processing power, particularly for the K1 methods used to determine the fire index.

[0031] In a preferred embodiment, the sensor module contains a measuring chamber which is provided with at least one opening leading to the environment of the sensor module. The VOC sensor is arranged in the measuring chamber (i.e. in such a way that it can detect the VOC concentration in the measuring chamber). If necessary, the above-mentioned sensors for pressure / temperature / volume, etc. are also arranged in / on the measuring chamber. This allows VOCs which are present in gaseous form to pass from the environment of the sensor module into the measuring chamber and be detected there by the VOC sensor. This also applies analogously to other sensors. The sensors are thus protected in the measuring chamber and yet are accessible from outside, i.e. from the environment, for the substances / quantities to be measured.

[0032] According to the invention, the fire alarm system contains at least one expansion anchor extending along a central axis. This anchor is designed to secure at least one of the sensor modules in an opening in a wall. A suitable wall is, for example, the wall of a storage compartment in or on which the sensor module is to be attached in order to determine the VOC concentration therein. The opening can then be inserted into the wall for the purpose of mounting the sensor module.

[0033] The expansion anchor can be inserted into the opening. The sensor module is designed as a core for the expansion anchor, meaning it can be secured in the opening in the expansion anchor and then in the opening. For this purpose, the sensor module or core can be inserted into the expansion anchor along its central axis and secured there. For example, the expansion anchor and core have corresponding threads and can be screwed together. In particular, the core can be removed from the expansion anchor if necessary, for example to service sensor modules (replace batteries, recharge the energy storage devices) or replace them (defects and replacement with a replacement module). The sensor modules and thus the sensors of the fire alarm system can be attached particularly easily in openings or walls.

[0034] For example, corresponding openings can be made in walls in a simple work step in order to make them suitable for mounting the fire alarm system or the sensor modules in a simple and cost-effective manner.

[0035] In a preferred variant of this embodiment, the expansion anchor contains a support element for the wall and a threaded part, as well as at least one expansion tab, which connect the support element and the threaded part to each other. The expansion tab is irreversibly or plastically deformable in order to engage behind the wall through the deformation. Either the core or an expansion tool can be screwed into the threaded part. The expansion tab can be (permanently) deformed by or with the aid of the screwed-in expansion tool.

[0036] After deformation, the support element and expansion tabs rest on opposite sides of the wall to secure the expansion anchor to the wall in the opening. In other words, the expansion anchor compresses the wall between the support element and expansion tabs.

[0037] The sensor module or the particularly rod-shaped core is designed with at least one screw-like section in order to be screwed into the threaded part and thereby fixed - if necessary releasably.

[0038] This design also provides a particularly simple way to secure the expansion anchors in the wall or opening. The threaded part fulfills a synergistic dual function: firstly, as an engagement point for the expansion tool, and secondly, for securing the sensor module in the expansion anchor.

[0039] The object of the invention is also achieved by a passenger cabin according to patent claim 9. The passenger cabin is one for a passenger aircraft or a passenger plane. The passenger cabin contains several storage compartments and the aforementioned fire alarm system. The passenger cabin or its storage compartments are the object(s) to be monitored by the fire alarm system. At least one of the sensor modules is arranged in each of the storage compartments in order to be able to detect the VOC concentration in a respective storage compartment.

[0040] The passenger cabin is particularly well protected by the fire alarm system, as potential fires or hazards that could potentially lead to a fire (heating) in storage compartments can be detected, if necessary before a fire actually breaks out.

[0041] The passenger cabin and at least some of its possible embodiments, as well as the respective advantages, have already been explained in connection with the fire alarm system according to the invention. In particular, the preferred embodiments mentioned above in connection with the fire alarm system also constitute preferred embodiments of the passenger cabin.

[0042] According to the invention, a fire alarm system in the above embodiment with expansion dowels is provided in the passenger cabin. For at least one of the storage compartments, the inner wall of this storage compartment is then the wall mentioned above with regard to the expansion dowels. The sensor module is fastened in the inner wall using the expansion dowel as its core. "Inner wall" is an inner wall of the storage compartment that does not face the passenger cabin, but rather the interior of the storage compartment. In particular, this is a wall that is permanently installed in the passenger cabin, for example not a flap or a pivoting part of the storage compartment, but rather its base body that is fixed in the cabin. The inner wall is therefore generally immobile in the cabin, which is why it is particularly well suited for mounting the sensor modules.

[0043] The object of the invention is also achieved by a method according to patent claim 10. The method serves or is configured to monitor a property for fires using the fire alarm system according to the invention. This is to be understood broadly here - as explained above - and includes monitoring for fire causes, i.e., potential fires, such as excessive heat.

[0044] The fire alarm system is deployed, or placed in or on the building, and put into operation. The sensor modules are attached to the building. The power module then supplies the power to or for the operation of the sensor module. The VOC sensor provides the sensor signal. The evaluation module at least preprocesses the sensor signal to produce the sensor data. The communication module transmits the sensor data to the central module. The central module uses the received sensor data to determine and provide a fire characteristic value based on the VOC concentrations.

[0045] The method and at least some of its possible embodiments, as well as the respective advantages, have already been explained analogously in connection with the fire alarm system and passenger cabin according to the invention. In particular, the preferred embodiments mentioned above in connection with the fire alarm system and passenger cabin also constitute preferred embodiments of the method.

[0046] In a preferred embodiment, the object being monitored is the aforementioned passenger cabin, which contains the fire alarm system. Thus, thanks to the method, the passenger cabin is particularly well protected, especially against potential fires, i.e., against their actual occurrence.

[0047] The invention is based on the following findings, observations, and considerations and also includes the following preferred embodiments. These embodiments are sometimes referred to as "the invention" for simplicity. The embodiments may also contain parts or combinations of the above-mentioned embodiments or correspond to them and / or may also include previously unmentioned embodiments.

[0048] According to the invention, a so-called “Tiny Distributed Carbonization Detection System” is obtained.

[0049] The result is a minimally invasive distributed system (fire alarm system) for the early detection of emerging fires. The system consists of a network architecture of small sensor modules placed in potentially hazardous areas (rooms / environments to be monitored). The system offers a cost-effective and scalable solution.

[0050] The invention is based on the realization that there are various fire detection technologies: from measuring CO2 concentrations to NIDR systems for detecting smoke particles to advanced systems based on infrared cameras that locate local heating. All of these systems are relatively bulky and take up a lot of space. And most of these systems only detect the fire after it has already broken out.

[0051] Currently known methods for fire detection include thermography (infrared cameras), smoke detection (microparticles), smoke detection (smoke detection), heat detection, and CO2 measurement. All systems operate autonomously.

[0052] The invention results in a particularly small module (sensor module) that can be easily integrated into any conceivable area and is designed to detect fires before they start. By measuring volatile carbon compounds (VOCs) and, in particular, other room-specific parameters such as temperature, pressure, and volume, a fire that is just starting can be detected before it becomes uncontrolled. Early detection is particularly suitable in environments where evacuation is not so easy. This also allows the exact location of the potential fire to be pinpointed (location of the sensor module that measures the unusual VOC concentration), so that the cause can be remedied before it is too late. The system can be used redundantly with conventional fire detection systems.

[0053] According to the invention, the following advantages arise: - Minimal impact on aesthetics. - Suitable for small spaces where space is important (e.g. loading areas). - Allows precise localization of the fire. - Report a developing fire before it starts.

[0054] According to the invention, a particularly comparatively small size of the sensor module as well as the localizability and early detection of a possible fire, in particular via AI-controlled algorithms, results.

[0055] The invention can be used as follows: 1) Use in the luggage compartment of civil aircraft. 2) Use in technical rooms / server rooms. 3) Use in transport boxes. 4) Use in any enclosed space where evacuation of people is difficult or even impossible.

[0056] The invention provides a minimally invasive distributed system for the early detection of emerging fires. The system consists, in particular, of a network architecture of small sensor modules (network-connected to the central modules) placed in potentially endangered areas (rooms / environments to be monitored). By processing various measurement data (VOC concentration, temperature, pressure, etc.) in real time, potential fire hazards can be detected and early warnings triggered to quickly respond to potential fires. The use of distributed sensors enables effective coverage of large areas and increases the reliability and responsiveness of the system. This results in a cost-effective and scalable solution for early fire detection in various environments.

[0057] The invention is based on the following findings: In safety-critical areas such as aircraft cabins or other environments where human life may be at risk, early fire detection is crucial. A fire in an overhead compartment of a (passenger) aircraft is a prime example. Rapid detection of an incipient fire allows for timely action to be taken to prevent or control the spread of the fire, ultimately helping to prevent injuries or even loss of life. While traditional fire alarm systems fulfill this function, they often have certain limitations that can limit their effectiveness.

[0058] A common problem with conventional fire alarm systems is their comparatively slow response time. They only detect the fire when it is already at an advanced stage, wasting valuable time during which the fire can spread uncontrollably. This delay can have devastating consequences, particularly in environments such as aircraft cabins, where people are confined in a confined space and evacuation can be difficult. In addition, many existing fire alarm systems are often bulky and difficult to install. These systems can be particularly problematic in areas where inconspicuous design or space constraints are a concern. In aircraft cabins, for example, every inch of space is precious, and installing large-capacity fire alarms can impact passengers or the cabin's aesthetics.

[0059] The invention addresses these challenges by presenting a system that enables early fire detection while being easily and discreetly integrated into various environments. By leveraging innovative sensor technology and advanced algorithms, this system can detect a fire in its early stages and trigger appropriate warnings before it develops into a serious threat.

[0060] By integrating into existing infrastructure or implementing it into new construction projects, this system can help improve safety and minimize potential risks while maintaining comfort and functionality.

[0061] To explain the basic concept of the invention, we will examine its use as an early fire detection module in the luggage compartment of civil aircraft. The functional principle can be abstracted and extended to many other application areas, such as server rooms, technical rooms, living spaces, etc. It should be noted that the system is particularly suitable for small, enclosed spaces.

[0062] The first point is the early detection of fires.

[0063] The detection of gaseous or vaporous volatile organic compounds (VOCs) offers the first opportunity to detect fires—for example, one caused by a defective lithium-ion laptop battery in a passenger's carry-on luggage—at a very early stage. VOCs are carbon compounds that evaporate at various temperatures and quickly mix with the ambient air.

[0064] Since many fires in technical systems are caused by electrical defects and, in most cases, slow, localized heating is evident, this leads to increased evaporation of substances from the heated materials, especially plastics, paints, and varnishes. A sudden increase in VOC concentration and a concomitant deterioration in air quality in a typically enclosed space, such as an overhead compartment in an aircraft cabin, can therefore indicate a technical defect that could potentially lead to a fire. An early (silent) alarm can prevent a potentially life-threatening fire by quickly eliminating the cause.

[0065] The size of the room and the temporal development of the measured value changes (time course of VOC concentration) play an important role here and must be evaluated, especially in conjunction with other parameters—for example, a simultaneous change in temperature and / or pressure. In the case of a full luggage compartment, correlation with the load volume will yield even better results.

[0066] The sensor modules are supplied with power as follows: The sensor modules can be supplied with energy using three different methods, with option c) being preferred for use in a luggage rack: a) By connecting to a supply line. This would ensure the modules' power supply for an indefinite period of time. Maintenance effort is significantly reduced, but integration into a permanent system is more complex. Furthermore, it should be considered that the additional lines increase the overall weight of the aircraft. b) By integrating a battery. Equipping the module with an integrated primary battery (e.g., lithium thionyl chloride) or an integrated secondary battery (e.g., lithium-ion) automatically increases the maintenance effort for the aircraft operator, especially with increasing aircraft size. Once the primary battery is almost depleted or the secondary battery charge level approaches 0%, the battery cells must be replaced by maintenance personnel. However, with the proposed advantageous design (expansion anchor and sensor module as the core), this should not be a lengthy process. c) By integrating a battery in combination with an energy harvesting system (EHS). Each sensor module is equipped with a rechargeable secondary battery (e.g., a lithium-ion 18650 cell). Here, the module's use in an aircraft overhead compartment is considered. In addition to a battery management system (BMS), there is an integrated energy harvesting module that converts ambient energy into electrical energy, buffers it, and uses it to relieve the load on the battery or recharge it. This should allow the module to be used for longer before it requires maintenance, either by charging or by replacing the battery cell.

[0067] In other application environments, energy harvesting via solar cells or Peltier elements might also be suitable. Depending on the intended application, a choice should be made between options a), b), and c). While, for example, in a stationary server room, numerous connection options are available and option a) is ideal, option c) should also be considered for use in an aircraft overhead compartment, given its cost-effective and simplified retrofit capability.

[0068] When using a battery without an energy harvesting system—as described in option b)—the reduced continuous runtime should be considered. Roughly speaking, VOC sensors with metal oxide technology and a heating membrane have an average energy consumption of 350 µW for a gas measurement every 10 seconds. With additional electronics for data evaluation and transmission, the expected operating time of a sensor module with a 12.96 Wh battery capacity is approximately 720 days.

[0069] The base station (central module) is used for data evaluation: The base station plays a crucial role in processing and analyzing the received measurement data (sensor data). Here, the information from the sensor modules is compiled, analyzed, and persisted and forwarded as needed. In addition to the sensor data, the current device status, including error messages, and the state of charge (SoC) of the built-in battery are transmitted. This enables early detection of problems and proactive maintenance.

[0070] One option for implementing the base station in the aircraft cabin is to expand a main computer system (e.g., a controller) with an additional module (built-in module and partial implementation) that can receive sensor data from distributed nodes (sensor modules) via a coordinated messaging protocol—preferably Bluetooth Low Energy or Wi-Fi—and send targeted control commands back via the same communication path. This additional module is to be understood as a network card (built-in module) and merely provides the main computer system with the ability to physically transmit and receive data.

[0071] In particular, integrated neural accelerators optimize the analysis process of the sensor data and provide enough computing power to generate local inferences for the measurement data (sensor signals) of all sensor modules - based on trained machine or deep learning models.

[0072] If a potential fire is predicted (fire characteristic), a silent alarm is triggered, alerting the cabin crew of the potential danger. To evaluate the warning, the relevant crew member can examine the affected overhead compartment more closely. The silent alarm can then be reset via the FAP (Flight Attendant Panel, input interface for cabin crew). This ensures safety on board without causing unnecessary panic among passengers.

[0073] The following system design results: Looking at the overall architecture of the system, the connection topology for use in the aircraft cabin is a setup with a sensor module in each of the storage compartments and two central modules, to each of which half of the sensor modules are connected.

[0074] This architecture can also be abstracted for all other application areas, while the basic principle remains the same: a base station operates several small intelligent gas sensors (sensor modules) – hence the "distributed" attribute in the name – and can predictively locate the origin of fires. The system can either be coupled with an automatic extinguishing system or involve a human to validate the alarm source.

[0075] To save energy, inference is (for now) not performed on the sensor module itself. Depending on future battery technology—which is likely to have significantly higher energy densities—the analysis of the gas composition (sensor signals) may also be performed on the sensor modules themselves (preprocessing to produce the sensor data). The same applies to future sensors with even lower power requirements. This minimizes the workload for the base station (central module) as well as the required network bandwidth (communication between sensor modules and the central module).

[0076] If we look at the structure of an individual sensor module, we can see that a gas sensor (VOC sensor) and a thermometer (these can also be located together in a single IC) are located at the tip in an air-permeable (openings) plastic housing (measuring chamber). The local heating of the electronics creates minimal convection currents, so that the ambient air is passively drawn in. Inside the housing of the sensor module is the evaluation electronics (evaluation module), which acquires, buffers, pre-processes and periodically transmits the sensor signals (data from the sensors) wirelessly to the base station (central module). Depending on the variant above (a, b, c), the module also contains a battery with BMS (Battery Management System) and an energy harvesting system (module). The positions and sizes of the individual components are not fixed and ultimately depend on the housing design: the energy harvesting module, for example, canIt can also be integrated at the front of the tip if it's a solar-powered sensor module. The battery can be larger or smaller, and the BMS and evaluation electronics (evaluation module) can also be located on a common circuit board.

[0077] Regarding visual design: The visual design is independent of the module's functionality. The finished product can be offered in various designs. One possibility is for retrofitting, minimally invasive integration into the overhead compartment of civil aircraft. The module then consists of a "core" that houses the sensors and Contains electronics, and a "sheath" (expansion anchor), which ensures the device's secure fit. The core and sheath are connected with a special thread (the core is screwed into the sheath).

[0078] To install the sensor module in the luggage compartment (storage compartment), a hole is first drilled through the wall. The casing (expansion anchor) of the sensor module is then pressed through the hole – similar to a cavity wall anchor – and then secured to the wall by screwing in a fixing screw (expansion tool) with a special thread (deformation of the expansion tabs). Unlike a conventional cavity wall anchor, a metric standard thread is not used here, as the core of the sensor module is significantly wider than a standard screw. Once the casing (expansion anchor) has been fixed to the wall by deformation, the fixing screw can be removed – the device (expansion anchor) remains firmly installed (permanent deformation of the expansion anchor). The sensor module can then be screwed into the casing with the matching thread on its housing.

[0079] Further features, effects, and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. Each of these figures shows a schematic diagram: Fig. 1 a section of a passenger aircraft or its passenger cabin (aircraft cabin) with the fire alarm system according to the invention and a connection topology of the fire alarm system, Fig. 2 the conceptual structure of a sensor module Fig. 1, Fig. 3 the course of a sensor signal recorded by the sensor module over time, Fig. 4 the sensor module Fig. 2 as core with expansion dowel as visualization of a possible housing design in an unassembled and Fig. 5 in a wall made of Fig. 1 assembled state.

[0080] Fig. 1 shows a section of a passenger aircraft 2 and its passenger cabin 4 in plan view. Shown are a total of three columns 6a-c of consecutively arranged rows of seats 8, each with three passenger seats 10. Above columns 6a and c, five storage compartments 12 for hand luggage, etc., of passengers not shown are arranged in a row one behind the other. Above the middle column 6b, pairs of storage compartments 12 are arranged side by side, five pairs of which are arranged in a row one behind the other. Thus, there are a total of twenty storage compartments 12 in the passenger cabin 4.

[0081] A fire alarm system 20 is installed in the passenger cabin 4 or the passenger aircraft 2. The passenger cabin 4 forms an object 120 to be monitored by the fire alarm system 20. The fire alarm system 20 contains a total of twenty sensor modules 22, each of which is Fig. 1 is symbolically indicated by a dot. The fire alarm system 20 also contains two central modules 24. Each of the sensor modules 22 is communicatively connected to one of the central modules 24 via communication links 26. The communication links 26 are wireless connections, which are symbolically represented as cable connections here only for the sake of clarity. Fig. 1 the connection topology of the fire alarm system 2 in the aircraft cabin / passenger cabin 4.

[0082] In Fig. 1 symbolically indicates one of the central modules 24, which has a distributed structure, namely, on the one hand, in the form of a physically or materially existing built-in module 70, here a network card for a main computer system 72 of the passenger cabin 4 or the passenger aircraft 2. On the other hand, in the form of a virtual or programmatic partial implementation 74, here a software element for software running in the main computer system 72. The central module 24 is implemented in the main computer system 72 through both components (built-in module 70, partial implementation 74).

[0083] The central modules 24 also each contain a neural accelerator 76, which operates with AI and supports the evaluation of the sensor data 46 as well as temperature T, pressure P and volume V in relation to the fire characteristic value 48.

[0084] Fig. Figure 2 shows—representative of all—the conceptual structure of one of the sensor modules 22 in detail. The sensor module contains an energy module 28, an evaluation module 30, a communication module 32, and a VOC sensor 34.

[0085] The energy module 28 here has a rechargeable battery 60 (including a battery management system) and an energy harvesting module 62, which absorbs energy from its surroundings in a manner not further specified, for example, by actuating a storage compartment flap (not shown). Alternatively, the energy module 28 contains—but additionally shown in the figure—a connection 64 for a supply line 66 of the passenger aircraft 2. This connection belongs to an on-board electrical system of the passenger aircraft 2 (not shown in detail). Thus, the sensor module 20 can also be supplied with energy from the on-board electrical system.

[0086] The energy module 28 is thus configured to supply or provide electrical energy for the operation of the sensor module 22.

[0087] During operation, the VOC sensor 34 delivers a sensor signal 36, represented symbolically here, which is correlated with a current VOC concentration 38 at the location of the sensor module 20 (i.e., in the air in an environment 44 of the sensor module 20), i.e., it maps or contains this concentration. The VOC concentration 38 is specifically detected here within a measuring chamber or measuring space 42 of the sensor module 22, in which the VOC sensor 34 is also arranged. For this purpose, the measuring space 42 has openings 40 through which the sensor, and thus the VOC sensor 34, communicates with the environment 44. In other words, the measuring chamber 42 is provided with openings 40 in order to communicate with the environment 44 in such a way that the VOC concentration 38 in the environment 44 corresponds to the VOC concentration 38 within the measuring chamber 42 and can thus be correctly detected by the VOC sensor 34.

[0088] The evaluation module 30 is configured to pre-process the sensor signal 36 into sensor data 46, which is also symbolically indicated here.

[0089] The communication module 32 is configured to transmit at least the sensor data 46 to the respective central module 24.

[0090] The central modules 24 are configured to determine a fire characteristic value 48 for the respective sensor module 22 or its surroundings 44 on the basis of the received sensor data 46 based on the VOC concentrations 38 contained therein or to be extracted therefrom by the sensor modules 22 (the corresponding information is contained in the sensor data 46 by preprocessing).

[0091] The environment 44 corresponds to an interior space 50 of a respective storage compartment 12. The fire characteristic value 48 is a binary value and reflects whether a fire situation is imminent or prevailing in the respective environment 44, i.e. in the respective interior space 50 (value “YES”) or not (value “NO”).

[0092] The interior space 50 thus forms the space 52 for each of the sensor modules 22 in which the respective sensor module 22 is installed during operation, in which the respective sensor module 22 is to be sensed for the respective VOC concentration 38.

[0093] The sensor module 22 also has a sensing element 110 for a current temperature T in the environment 44, a sensing element 112 for a current pressure P in the environment 44, and a sensing element 114 for a current free or air volume V in the environment 44 or the interior 50 of the storage compartment 12. The volume V is the current air volume of the interior 50, i.e., its empty volume minus the volume of inserted objects such as luggage, clothing, etc.

[0094] The values ​​of temperature T, pressure P and volume V are recorded in the respective sensor module 22, also pre-processed in the evaluation module 32 and transmitted via the communication module 32 to the central module 24, where they are used to determine the fire characteristic value 48.

[0095] Fig. 3 shows symbolically for one of the storage compartments 12 a time course 54 of the VOC concentration 38 over time t.

[0096] In the example, an electronic device (not shown) is located in the storage compartment 12 in question, which suffers an internal defect at a time t1. Due to the defect, the device begins to heat up locally at a defective component. Due to the rising temperature in the device, volatile organic compounds (VOCs) begin to escape from the component, neighboring housing parts, and paints, which is why the VOC concentration 38 in the interior 50 of the storage compartment 12 exhibits an increase 56 over time t.

[0097] This increase 56 is ultimately detected in the central module 24 and mapped to the fire characteristic value 48 such that at time t2, its binary value changes from "NO" to "YES." Thus, a potential fire is detected, as it is assumed that the faulty device will continue to heat up even after time t2 and eventually begin to burn.

[0098] However, due to the corresponding detection (value “YES” for the storage compartment 12), the fire alarm system 20 triggers a silent alarm for cabin crew (not shown), indicating the relevant storage compartment 12 in which the rise 56 was detected.

[0099] The cabin crew can now inspect the corresponding storage compartment 12 and identify the device as a source of danger and move it to safety to prevent a fire in the storage compartment 12 and thus the passenger cabin 4. Due to the silent alarm, no panic is caused among the passengers (not shown).

[0100] The fire index 48 is therefore correlated with a time course 54, here the increase 56, of the VOC concentration 38.

[0101] Fig. Figure 4 shows—representatively for all—one of the sensor modules 22 in terms of its external design. All components of the sensor module 22 are housed in a housing 80. From the outside, only the openings 40 leading into the measuring chamber 42 inside the housing 80 are visible.

[0102] The fire alarm system 20 contains a fastening means for each of the sensor modules 22, here in the form of an expansion dowel 90. The expansion dowels 90 serve to fasten the respective sensor module 22 in an opening 84 of a wall 86 (see Fig. 5). In the present example, the wall 86 is a respective inner wall 14 of a respective storage compartment 12, which is why the sensor modules 22 in the form of the cores 92 of the expansion dowels 90 are attached to the respective inner wall 14.

[0103] The expansion anchor 90 extends along a central axis 88. The sensor modules 22 are each designed as a core 92 for the expansion anchor 90. The core 92 can be inserted into the expansion anchor 90 in the direction of an arrow 94. The core 92 can also be fixed therein. For this purpose, the expansion anchor 90 and core 92 have corresponding threads 96, which are only symbolically indicated in the figure. In other words, the core 92 can be screwed into the expansion anchor 90 and also removed from it again, so that it can be removed from the expansion anchor 90 again, if necessary, in the opposite direction to the arrow 94.

[0104] The expansion anchor 90 has a support element 100 for the wall 86 and a threaded part 102 in which the thread 96 is inserted. The support element 100 and the threaded part 102 are connected to each other by four expansion tabs 104, of which only three are visible in the figures. The expansion tabs 104 are irreversibly or plastically deformable.

[0105] Fig. 5 shows how, in the inserted state, the deformed expansion tabs 104 engage behind the wall 86 and hold the expansion dowel 90 in the wall 86. In other words, the wall 86 is clamped or pressed between the deformed expansion dowel 90 and the support element 100.

[0106] To perform this deformation and compression, an expansion tool (not shown) can be inserted into the expansion anchor 90 instead of the core 92. This expansion tool also has a corresponding thread 96 that engages with that in the threaded part 102. The expansion tool is also supported on the support element 100. By appropriate screwing, with the expansion anchor 90 inserted into the wall 86 / opening 84, the threaded part 102 is then moved forward in the direction of an arrow 106 towards the support element 100, whereby the distance between the support element 100 and the threaded part 102 is reduced and the expansion tab 104 is irreversibly deformed in order to effect the above-mentioned clamping of the expansion anchor 90 to the wall 86 and thus its fixation.

[0107] In Fig. 1 schematically outlines a method for monitoring the passenger cabin 4 as the object 120 to be monitored using the fire alarm system 2.

[0108] In a step S1, the fire alarm system 20 is provided and the sensor modules 22 are mounted in the passenger cabin 4.

[0109] In a step S2, the energy module 28 supplies the sensor modules 22 with energy for their operation.

[0110] In a step S3, the VOC sensors 34 generate or deliver the sensor signals 36, thus measuring the current VOC concentration 38.

[0111] In a step S4, the evaluation module 30 preprocesses the sensor signals 36 into the sensor data 46.

[0112] In a step S5, the communication module 32 transmits the sensor data 46 to the central modules 24.

[0113] In a step S6, the central modules 24 determine the fire characteristics 48 for the respective storage compartments 12 based on the received sensor data 46 and provide them based on the VOC concentrations 38.

[0114] In a step S7, the passenger cabin 4 is monitored for fire based on the fire characteristics 48 - here even in the sense of an imminent fire hazard, i.e. before an actual fire breaks out. List of reference symbols 2 passenger aircraft 4 passenger cabins 6a-c Column 8 row of seats 10 passenger seats 12 storage compartments 14 Interior wall (storage compartment) 20 fire alarm system 22 Sensor module 24 central module 26 Communication connection 28 Energy module 30 Evaluation module 32 Communication module 34 VOC sensor 36 Sensor signal 38 VOC concentration 40 Opening 42 Measuring room 44 Environment (sensor module) 46 sensor data 48 fire index 50 interior (storage compartment) 52 Space (to be sensed) 54 Timeline 56 increase 60 battery 62 Energy Harvesting Module 64 connection 66 supply line 70 built-in module 72 Main computer system 74 Partial implementation 76 neural accelerators 80 housings 84 Breakthrough 86 wall 88 Central axis 90 expansion anchors 92 core 94 Arrow 96 threads 100 support element 102 threaded part 104 Spreader bar 106 Arrow 110 Detection element (temperature) 112 Detection element (pressure) 114 Recording element (volume) 120 objects (to be monitored) T Temperature P pressure V Volume t time t1,2 time point

Claims

[1] Fire alarm system (20) for monitoring an object (120) for fires, - with a plurality of sensor modules (22), wherein each of the sensor modules (22): - an energy module (28) configured to supply energy for operation of the sensor module (22), - and a VOC sensor (34) which delivers a sensor signal (36) during operation, wherein the sensor signal (36) is correlated with a current VOC concentration (38) at the location of the sensor module (22), - and an evaluation module (30) which is designed to at least pre-process the sensor signal (36) into sensor data (46) which are correlated with the VOC concentrations (38) measured by the VOC sensor (34), - and a communication module (32) which is designed to transmit at least the sensor data (46) to a central module (24), contains, - with the at least one central module (24) which is configured to determine and provide a respective fire characteristic value (48) for an environment (44) of the respective sensor module (22) based on the received sensor data (46) based on the VOC concentrations (38), - wherein the fire alarm system (20) contains at least one expansion dowel (90) extending along a central axis (88) and designed to fasten at least one of the sensor modules (22) in an opening (84) in a wall (86), wherein the expansion dowel (90) can be inserted into the opening (84) and the sensor module (22) is designed as a core (92) for the expansion dowel (90), wherein the core (92) can be inserted into the expansion dowel (90) along the central axis (88) and can be fixed therein. [2] Fire alarm system (20) according to claim 1, characterized bythat the sensor module (22) contains a detection element (110) for a current temperature (T) and / or a detection element (112) for a current pressure (EP) on the sensor module (22) and / or a detection element (114) for a current volume (V) of a space (52) to be sensed, in which the sensor module (22) is installed during operation. [3] Fire alarm system (20) according to one of the preceding claims, characterized by that the fire characteristic value (48) is correlated with a time course (54) of the VOC concentration (38). [4] Fire alarm system (20) according to one of the preceding claims, characterized by that the energy module (28) contains a connection (64) for an energy supply line (66) and / or a battery (60) and / or an energy harvesting module (62). [5] Fire alarm system (20) according to one of the preceding claims, characterized bythat the central module (24) contains a built-in module (70) for a main computer system (72) of an object (120) to be monitored by the fire alarm system (20) and a partial implementation (74) for the main computer system (72). [6] Fire alarm system (20) according to one of the preceding claims, characterized by that the central module (24) and / or the evaluation module (30) contains a neural accelerator (76). [7] Fire alarm system (20) according to one of the preceding claims, characterized by that the sensor module (22) contains a measuring chamber (42) provided with at least one opening (40) leading to the environment (44) of the sensor module (22), and the VOC sensor (34) is arranged on the measuring chamber (42). [8] Fire alarm system (20) according to one of the preceding claims, characterized bythat the expansion dowel (90) contains a support element (100) for the wall (86) and a threaded part (102) and at least one expansion tab (104) connecting the support element (100) and the threaded part (102), which can be plastically deformed while engaging behind the wall (86), wherein either the core (92) or an expansion tool can be screwed into the threaded part (102), wherein the expansion tab (104) can be deformed by the screwed-in expansion tool. [9] Passenger cabin (4) for a passenger aircraft (2), with several storage compartments (12) and with a fire alarm system (20) according to one of the preceding claims, wherein the passenger cabin (4) is the object (120) to be monitored and at least one of the sensor modules (22) is arranged in each of the storage compartments (12), - wherein for at least one of the storage compartments (12) the inner wall (14) thereof is the wall (86) and the sensor module (22) is fastened in the inner wall (14) by means of the expansion dowel (90) as its core (92). [10] A method for monitoring an object (120) for fires, comprising: - a fire alarm system (20) according to one of claims 1 to 8 is provided, - the sensor modules (22) are attached to the object (120), - the energy module (28) supplies the energy for the operation of the sensor module (22), - the VOC sensor (34) provides the sensor signal (36), - the evaluation module (30) at least pre-processes the sensor signal (36) to the sensor data (46), - the communication module (32) transmits the sensor data (46) to the central module (24), - the central module (24) determines and provides the respective fire characteristic value (48) based on the received sensor data (46) based on the VOC concentrations (38), - the object (120) is monitored for fires using the fire characteristics (48). [11] Method according to claim 10, characterized by that a passenger cabin (4) according to claim 9 is monitored as the object (120).

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