System and method for servicing fire alarms
Patent Information
- Application Number
- EP2024704325
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-29
- Filing Date
- 2024-01-31
- Publication Date
- 2026-02-11
AI Technical Summary
Fire detectors are often inadvertently or intentionally obstructed, preventing them from functioning correctly due to the placement of dust protection caps, adhesive tape, or other objects, which can go undetected until a visual inspection, potentially leaving them non-functional until the next inspection, risking undetected fires.
A maintenance system utilizing unheated temperature sensors, such as thermistors, to detect thermal fluctuations at inlet openings of fire detectors, with a control unit evaluating signal bandwidth to determine if smoke entry is hindered, and storing messages in a memory for evaluation, allowing for remote monitoring and service messages to be issued when no fluctuations are detected, indicating potential obstruction.
Enables continuous monitoring of fire detector functionality without visual inspection, reducing the risk of undetected fires by identifying obstructed detectors and prioritizing their inspection, thus ensuring timely maintenance and reducing costs and effort in facility management.
Smart Images
Figure EP2024052342_03102024_PF_FP_ABST
Abstract
Description
[0001] Description System and method for maintaining fire detectors The invention relates to a maintenance system and a method for maintaining fire detectors, in particular for detecting soiling or impermissible covering of at least one inlet opening for smoke or fire gas in a fire detector. So-called dust protection caps are often fitted to fire detectors installed in buildings, for example to prevent dust from getting into the measuring chamber during construction work and thus triggering an unwanted alarm. In practice, the fire detector is also often taped over with adhesive tape, for example to prevent the detector from being painted during painting work. For both of these reasons, other types of caps, bags or other objects are often attached to the detector to prevent the fire detector from being triggered accidentally.Unfortunately, these objects are often forgotten to be removed after work has been completed, or they are deliberately added to suppress any alarm. As a result, the fire detector is no longer capable of triggering an alarm and can no longer fulfill its purpose. These tamperings with the detector, which prevent it from triggering an alarm in the event of a fire, are normally detected during a semi-annual visual inspection, for example, and can then be removed. If such tampering were to occur one day after the visual inspection, in the worst case scenario the detector would be non-functional until the next inspection and would not be able to detect a fire. The object of the present invention is to determine the functionality of a fire detector without a visual inspection.The object is achieved by a maintenance system for fire detectors, installed in one or more fire compartments, wherein each fire detector is set up to record at least one fire parameter in the event of a detected fire, wherein the fire detector has a housing with at least one inlet opening, a sensor system which communicates with the ambient air via this inlet opening for recording a flow in the area of the sensor system, and a control unit, - wherein the control unit is connected to the sensor system for evaluating the operational capability of the fire detector, - wherein the sensor system has at least one preferably unheated temperature sensor arranged in the area of at least one of the inlet openings for measuring ormetrological detection of thermal fluctuations, in particular at least one thermistor, preferably at least one NTC, - wherein the control unit is connected to the at least one temperature sensor for detecting a respective temperature measurement signal, and - wherein the control unit is further configured to detect whether or not thermal fluctuations exist in the inlet opening, - wherein the control unit is further configured, in the event that no thermal fluctuations are detected, to enter a corresponding message into a memory (database, list) of an evaluation unit (server) of the maintenance system. By using thermal sensors, i.e. temperature sensors, in fire detectors, fluctuations are detected, i.e. it is detected whether smoke can get into the smoke inlet openings and thus into the measuring chamber of the fire detector.If fluctuations are detected, there is a very high probability that smoke entry is unobstructed. If no fluctuations are detected, there is a risk or the probability is high that smoke entry is obstructed. Temperature-dependent resistors such as NTC (negative temperature coefficient thermistor) or PTC (positive temperature coefficient thermistor), i.e., hot conductors or cold conductors, or corresponding semiconductor sensors such as semiconductor diodes, can be used as temperature sensors. Fire detectors with unheated temperature sensors, in particular with unheated thermistors, preferably with unheated NTCs, are advantageously used to detect thermal fluctuations in the area of the inlet openings, or fire detectors are equipped with such sensors.It can be assumed that a fire detector with a short operating time will have hardly any contamination in the area of the inlet openings, preventing the smoke or fire gases to be detected from flowing through the inlet opening into the interior of the fire detector for fire detection. One reason for the lack of fluctuations is most likely that the inlet openings have been covered with a protective cap or, in the absence of such a cap, taped over with adhesive tape to prevent the fire detectors from being painted over during upcoming painting work.A first advantageous embodiment of the invention is that the detection of thermal fluctuations in the control unit (MC) occurs by evaluating the signal bandwidth of signal fluctuations, wherein the message that no thermal fluctuations were detected is entered into the memory (database, list) of the evaluation unit (server) if the signal bandwidth of signal fluctuations of at least one of the detected, preferably all, temperature measurement signals (S1-S4) falls below a value of 30 mK, in particular 20 mK, preferably 15 mK, for a minimum time (MZ). At least 90% of the detected signal fluctuations, preferably at least 95% of the detected signal fluctuations, occur within this signal bandwidth.A further advantageous embodiment of the invention is that the evaluation unit (server), after evaluating the messages entered in the memory (database, list) that there is no fluctuation, issues a service message if the evaluation indicates a lack of fluctuation in a fire compartment. The service message can be output, for example, on a display of a fire alarm control panel. The service message advantageously includes a reference to the affected fire compartment. The evaluation unit is advantageously implemented in an appropriately configured cloud server. A further advantageous embodiment of the invention is that the messages entered in the memory (database, list) in a defined monitoring interval are evaluated by the evaluation unit with regard to the number of messages and / or the respective installation location of the detectors that report no fluctuation.This allows thermal fluctuations to be determined and evaluated specifically for an installation location. A further advantageous embodiment of the invention is that the defined monitoring interval is one day, one month, or one year. The minimum time for the monitoring interval is in a range from 1 day to 1 year, in particular in a range from 1 day to 1 month, and preferably in a range from 1 day to 1 week. To detect the expiration of the minimum time, the fire detector can have a timer. The timer can be an electronic counter module. This can already be integrated into the control unit. Alternatively, the timer can also be implemented as software that runs on a processor-supported control unit, in particular on a microcontroller.The control unit is advantageously configured to initially set the timer's counter reading to a counter start value corresponding to the minimum time, which the timer continuously counts down. A further advantageous embodiment of the invention is that the memory (database, list) of the evaluation unit (server) can be read via cloud access and / or via internet access and / or via remote maintenance. A facility manager or service employee can thus access the memory or read the memory contents, for example, in a building control center. A further advantageous embodiment of the invention is that in the event of an inspection, particularly an annual inspection, only those fire detectors are checked for which no fluctuations were detectable. This saves effort and costs in the facility management of the building.A further advantageous embodiment of the invention is that a service message is issued if there are two or more fire detectors in a fire compartment, in particular in a room, of which one fire detector detects fluctuations but the other does not. If there are two or more detectors in a room, of which one detector detects fluctuations but the other does not, it can be assumed with a high probability that the detector without fluctuations is covered. In this case, a service message or technical information can be issued immediately. A further advantageous embodiment of the invention is that the maintenance system, in particular the evaluation unit, is implemented in a cloud infrastructure. This allows the maintenance system to be easily expanded to include additional fire detectors or adapted to a changed room layout.The object is further achieved by a method for the maintenance of fire detectors, in particular for the detection of contamination or an inadmissible covering of at least one inlet opening for smoke or fire gas in a fire detector, - wherein at least one preferably unheated temperature sensor, in particular at least one preferably unheated thermistor, is used for measuring ormetrological recording of thermal fluctuations in the area of one of the inlet openings is arranged, - wherein a temperature measurement signal is recorded by the respective temperature sensor, - wherein a message for the absence of moving ambient air around the at least one temperature sensor is entered into the memory of an evaluation unit, and - wherein the evaluation unit (server) issues a service message after evaluating the messages entered in the memory (database, list) that there is no fluctuation if the evaluation indicates a lack of fluctuation in a fire compartment. Temperature-dependent resistors such as NTC (for Negative Temperature Coefficient Thermistor) or PTC (for Positive Temperature Coefficient Thermistor, i.e. hot conductors or cold conductors), or corresponding semiconductor sensors such as semiconductor diodes, can be used as temperature sensors.Fire detectors with unheated temperature sensors, particularly with unheated thermistors, preferably with unheated NTCs, are advantageously used or are equipped with such sensors in the fire detectors. It can be assumed that a fire detector with a short operating time will have hardly any contamination in the area of the inlet openings, preventing the smoke or fire gases to be detected from flowing through the inlet opening into the interior of the fire detector for fire detection. One reason for the lack of fluctuations is most likely that the inlet openings have been covered with a protective cap or, in the absence of such a cap, taped over with adhesive tape to prevent the fire detectors from being painted over during upcoming painting work.A further advantageous embodiment of the invention is that the message for the absence of moving ambient air around the at least one temperature sensor is generated when the signal bandwidth of signal fluctuations of at least one of the detected, preferably all, temperature measurement signals (S1-S4) falls below a value of 30 mK, in particular 20 mK, preferably 15 mK, for a minimum period (MZ). At least 90% of the detected signal fluctuations, preferably at least 95% of the detected signal fluctuations, fall within this signal bandwidth.A further advantageous embodiment of the invention is that the messages entered into the memory (database, list) in a defined monitoring interval with regard to the number of messages and / or with regard to the respective installation location of the detectors that do not report any fluctuation are analyzed by the evaluation unit to determine whether the evaluation indicates a lack of fluctuation in a fire compartment. This allows thermal fluctuations to be determined and evaluated specifically for an installation location. A further advantageous embodiment of the invention is that the defined monitoring interval is one day, one month, or one year. The minimum time for the monitoring interval is in a range from 1 day to 1 year, in particular in a range from 1 day to 1 month, and preferably in a range from 1 day to 1 week.To detect the expiration of the minimum time, the fire detector can have a timer. The timer can be an electronic counter module. This can already be integrated into the control unit. Alternatively, the timer can also be implemented as software that runs on a processor-based control unit, in particular on a microcontroller. The control unit is advantageously configured to initially set the timer's counter reading to a counter start value corresponding to the minimum time, which the timer continuously counts down. A further advantageous embodiment of the invention is that the memory (database, list) is read by the evaluation unit via on-premise access and / or via cloud access and / or via internet access and / or via remote maintenance. This allows flexible access to the memory via alternative interfaces.A further advantageous embodiment of the invention is that during a maintenance inspection, particularly during an annual maintenance inspection, only those fire detectors are checked for which no fluctuations were detected. This saves costs and time. A further advantageous embodiment of the invention is that the evaluation unit issues a service message if there are two or more fire detectors in a fire compartment, particularly in a room, and at least one of them is not reporting any fluctuations. If there are two or more detectors in a room, one of which detects fluctuations but the other does not, it can be assumed with a high degree of probability that the detector without fluctuations is covered. In this case, a service message or technical information can be issued immediately.A further advantageous embodiment of the invention is that the maintenance system, in particular the evaluation unit, is implemented in a cloud infrastructure. This allows the maintenance system to be easily expanded to include additional fire detectors or adapted to a changed room layout. The invention and advantageous embodiments of the present invention are explained using the example of the following figure.1 shows an example of a fire detector according to the invention with four exemplary thermistors distributed in the region of the inlet opening, FIG. 2 shows a plan view of the fire detector according to the viewing direction II shown in FIG. 1, FIG. 3 shows a block diagram of an electronic control unit of the fire detector according to the invention, FIG. 4 shows the curve of an unfiltered temperature measurement signal from a thermistor, arranged in the region of an inlet opening of a fire detector according to the invention, FIG. 5 shows the curve of the magnitude of a high-pass filter signal after filtering the unfiltered temperature measurement signal from FIG. 4 in an enlarged view, FIG. 6 shows the curve of the magnitude of a filter output signal after filtering the high-pass filter signal from FIG. 5 by means of a low-pass filter in a greatly enlarged view, FIG. 7 shows an exemplary maintenance system for fire detectors, and FIG. 8 shows an exemplary flow chart for a method for maintaining fire detectors.FIG 1 shows an example of a fire detector M according to the invention with four exemplary thermistors T1-T4 distributed in the region of the inlet opening OF as an example of temperature sensors. G denotes a housing of the fire detector M, which comprises a base body GG and a hood H. In between, the fire detector M has, for example, an inlet opening OF that completely surrounds a main axis A of the fire detector M. The thermistors T1-T4 shown are part of a sensor system for detecting a flow in the region of the sensor system. The hood H shown is supported, for example, by a measuring chamber accommodated in the interior of the housing G and communicating with the ambient air via the at least one inlet opening OF. The optical measuring chamber MK here is the preferred embodiment of a fire detection unit MK for detecting the at least one fire characteristic and is also referred to as a labyrinth.It is characterized by unspecified slats. The latter are designed to shield the optical measuring chamber MK from ambient light entering through the inlet opening OF, on the one hand, and to be permeable to smoke or fire gases to be detected, on the other. N designates an insect screen that prevents insects and the like from entering the interior of the measuring chamber MK through the inlet opening OF. The four thermistors T1-T4 are arranged radially outward relative to the main axis A to the grille N. The grille N is therefore located between the thermistors T1-T4 and the slats of the optical measuring chamber MK. If the inlet opening OF is covered, for example, by a protective hood, the thermistors T1-T4 are then aerodynamically shielded from the ambient air.In the present example, the optical measuring chamber MK has, in a known manner, two light-emitting diodes (LEDs) of different colors, each arranged in a scattered light arrangement to a photosensor PD. Another sensor can also be arranged in the measuring chamber MK, e.g. for detecting toxic gases such as carbon monoxide (CO), or a humidity sensor as a comfort sensor, e.g. In further exemplary embodiments, the optical measuring chamber can also have two light-emitting diodes (LEDs) with the same wavelength. All of the aforementioned sensors as well as the light-emitting diode (LED) can be arranged together with an electronic, processor-supported control unit MC of the fire detector M on a circuit carrier PCB of the fire detector M. The control unit MC of the fire detector M is preferably a microcontroller that is set up or programmed to output an alarm AL in the event of a detected fire, symbolized by an arrow.In this case, the alarm is triggered when an excessively high scattered light level or an excessively high CO level of a CO sensor in the measuring chamber MK is detected. An alarm could also be triggered if the thermistor has detected a maximum value (max value) or an excessively rapid increase. According to the example in FIGS. 1 and 2, the four thermistors T1-T4, which are located radially outward with respect to the main axis A of the fire detector M, are evenly distributed in the circumferential direction. The thermistors T1-T4 are preferably NTCs. The latter are extremely robust, very small in their dimensions, and also cost-effective. Such NTCs have, apart from the connecting wires, maximum dimensions in their three dimensions in the range of 1 mm to 5 mm. Typically, two of the three dimensions are even smaller than 2 mm.This extremely compact design with its low thermal capacitance ensures a fast thermal response of a maximum of 3 s, in particular a maximum of 2 s, and preferably a maximum of 1 s. Short-term, minor temperature fluctuations in the moving ambient air (thermal fluctuations) then also become apparent at the two electrical connections of the respective NTC in the form of corresponding, metrologically detectable ohmic resistance changes and thus also in an associated electrical temperature measurement signal. The previously mentioned thermistors T1-T4 are thus set up or intended to output a respective temperature measurement signal. The NTC for the respective thermistors T1-T4 can, for example, have an ohmic resistance value of 10 kΩ, 20 kΩ, 25 kΩ, 50 kΩ, or 100 kΩ specified for an ambient temperature of 25°C.The respective NTC is typically connected in series with a resistor (component) that has a constant resistance value. The ohmic resistance value of the resistor (component) preferably corresponds to the resistance value of the respective NTC at 25°C. This series connection is connected to a constant voltage difference, such as a voltage difference of 3.0 V, typically formed from the voltage difference between a reference potential (ground) and a positive constant supply voltage. The center tap of the series connection is then fed to an input of an A / D converter. The latter is usually already integrated in a microcontroller MC. Preferably, the electronic control unit or the microcontroller MC is set up or programmed to apply this voltage difference only for the duration of an (ongoing) A / D conversion. This can, for example,by electrically controlling a switching element connected in series with this series circuit, such as a transistor. This further minimizes power consumption. Alternatively, instead of the ohmic resistor (component), a constant current source can be connected in series with the NTC or, in general, with the thermistor. Alternatively or additionally, a signal amplifier can be connected between the center tap of the series circuit, the output signal of which is connected to the input of the A / D converter. The control unit MC shown is advantageously configured or programmed to output a warning message WM if the (average) signal bandwidth of signal fluctuations in at least one of the detected, preferably in all, temperature measurement signals S1-S4 falls below a value of 30 mK, in particular 20 mK, preferably 15 mK, for a minimum time MZ.The minimum time MZ is in particular in a range from 1 day to 1 year, in particular in a range from 1 day to 1 month, and preferably in a range from 1 day to 1 week. FIG 3 shows a block diagram of an electronic control unit MC of the fire detector M according to the invention, implemented as a microcontroller. A software program PRG is executed on the microcontroller MC by its processor unit in order to control the associated light-emitting diode LED in the case of a connected optical fire detection unit, to receive a sensor signal from the associated photodiode PD and to analyze this using an evaluation program and, if necessary, to output a fire alarm AL. The software program PRG is also executed in order to output a warning message WM in the event of a lack of moving ambient air around the at least one thermistor T1-T4, according to the invention.The absence of thermal fluctuations is an indication of excessive contamination or a blockage of at least one inlet opening. As shown in FIG. 3, the microcontroller MC has, for example, four integrated A / D converters (ADCs), which convert the temperature measurement signals S1-S4 originating from the four thermistors T1-T4 into a respective digital temperature measurement signal D1-D4. The four digital signals D1-D4 are converted into a respective high-pass signal F in a functional block (not further designated) using a respective high-pass filter HP. H1 -F H4 filtered or converted. In this example, the four high-pass signals F H1 -F H4 preferably fed to a respective moving root mean square filter RMS. The filter output signals F provided on the output side O1 -F O4are subsequently monitored according to the invention to determine whether at least one of the filter output signals F O1 -F O4 exceeds a specified limit value GW. If this is the case, the counter value of a timer TIMER implemented as software in the microcontroller MC is set to a starting counter value corresponding to the minimum time and started to count down. The timer TIMER is reset each time or restarted with the starting counter value if at least one of the filter output signals F O1 -F O4 exceeds the specified limit value GW again. Finally, according to the invention, the warning message WM for the absence of moving ambient air around the at least one thermistor T1-T4 is output if the timer TIMER reaches the counter value zero or another specified counter value. Alternatively, the four high-pass signals F H1 -F H4also be fed to a respective moving arithmetic mean filter AVS or a low-pass filter TP. The previously described filters HP, RMS, AVS, TP are digital filters, preferably FIR filters. FZ denotes a filter time for the moving average filters RMS, AVS, or for the low-pass filter TP. According to one embodiment, the control unit MC can be connected to an operating timer BZM, which is started when the electrical power supply to the fire detector begins. In this case, the control unit MC is set up or programmed (PRG) to issue a covered message COV, or the warning message WM together with a covered message COV as an indication of an impermissible covering of at least one inlet opening, if the signal bandwidth of signal fluctuations in at least one of the recorded, preferably in all temperature measurement signals S1-S4, a minimum waiting time WZ in a range of 1 hour to 3 days,preferably from 1 hour to 24 hours, falls below a value of 30 mK, in particular 20 mK, preferably 15 mK, and if, in addition, an operating time measurement value BZW of the operating time meter BZM is less than 2 years, preferably less than 1 year. FIG. 4 shows the curve of an unfiltered temperature measurement signal from a thermistor,arranged in the area of an inlet opening of a fire detector according to the invention. The temperature measurement signal was sampled, for example, with a sampling time of 2 seconds and recorded over a period of just over a month (August 28 to October 2) in a non-air-conditioned room in the applicant's development department. The temperature measurement signal reflects the ambient temperature profile, with the respective maximum temperatures during the day and the respective minimum temperatures at night. The maximum temperature range for this period was approximately 8 degrees Celsius. FIG. 5 shows the profile of the magnitude of a high-pass filter signal after filtering the unfiltered temperature measurement signal from FIG. 4 in an enlarged view. The high-pass filter used to decouple the DC component in the temperature measurement signal had a filter time of 25 seconds.which corresponds to a filter frequency of 1 / 25 of a second. Magnified by measurement, comparatively large signal fluctuations in the form of signal fluctuations with absolute maximum fluctuations of approximately 80 mK, which are associated with thermal fluctuations in the ambient air, are evident up until the protective cover is put in place (see the two boxes labeled "Detector Cover"). These thermal fluctuations essentially surround the immediate area around the thermistor being measured. Surprisingly, these signal fluctuations decrease very quickly when the protective cover is put in place. This is due to the shielding effect of the protective cover. Subsequently, the magnitude of the filtered temperature measurement signal only shows signal fluctuations with maximum fluctuations of approximately 6 mK, which corresponds to a signal bandwidth of twice that value, approximately 12 mK.and is thus approximately one order of magnitude lower than in the period before the inlet opening was covered with the protective cap. The high-pass filtering with the absolute temperature differences shown means that the temperature measurement signal remains above the zero line and related to the zero line. The reference symbol B / 2 denotes half the signal bandwidth of the signal fluctuations during the period in which the detector is covered. FIG. 6 shows the curve of the magnitude of a filter output signal after filtering the high-pass filter signal from FIG. 5 using a low-pass filter (e.g., 1st order IIR filter) with a filter time of 60 minutes in a greatly enlarged view. As FIG. 6 shows, the absolute values of the low-pass signal drop drastically from approximately 5 mK before the protective cap is put on to a value of approximately 1 mK after the protective cap is put on. The reference symbol GW indicates a limit value with an exemplary value of 1.5 mK,which is definitely not exceeded by the absolute values of the low-pass filter signal during the period the detector is covered. This very large and consistently reproducible signal difference advantageously enables reliable discrimination as to whether the inlet openings have been covered or are completely dirty. So-called dust caps are often placed on installed fire detectors, for example, to prevent dust from entering the measuring chamber during construction work and thus triggering an unwanted alarm. In practice, the fire detector is also often taped over with adhesive tape, for example, to prevent the detector from being painted during painting work. For both reasons, other types of caps, bags, or other objects are often placed on the detector to prevent accidental activation of the fire detector. Unfortunately, it is often forgottenThese objects are removed after completion of the work, or such objects are deliberately applied to suppress any alarm. As a result, the detector (especially a fire detector) is no longer capable of triggering an alarm and can no longer fulfill its purpose. These tamperings with the detector, which prevent the alarm function in the event of a fire, are normally detected during a semi-annual visual inspection and can then be removed. If such a tampering were to occur one day after the visual inspection, in the worst case, the detector would be non-functional until the next inspection, which would be almost half a year later, for example, and would not be able to detect a fire. According to the invention, the smallest thermal fluctuations in the millikelvin range are measured and evaluated, which can be used to detect such a cover. Unfortunately, in practice, there are also enclosed spaces,in which almost no fluctuations are measurable. In these rooms, reliable detection of covered detectors is not possible, as the algorithm cannot distinguish whether the detector has been covered or whether there are simply no fluctuations in the room. This means that if fluctuations are detected, the smoke entry is very likely unobstructed. If no fluctuations are detected, there is a risk or a high probability that the smoke entry is obstructed. It is suggested to keep all the detectors in a list,where no fluctuations were measurable over a certain period of time. The period can typically be set to at least 24 hours up to one month, but in any case shorter than the inspection interval applicable in this facility / country (e.g., an inspection interval of 6 months). Normally, sufficient fluctuations in rooms occur simply when a door is opened or when a person moves in the room, or of course when devices with a fan are started up in this room. For the specifications of these fluctuation monitoring periods: • Normally, fluctuations should occur within one day when the room is used or entered by people. • If daily use is not always the case, extending the monitoring interval to one week is recommended. • A monitoring period of one month is recommended to avoid falsely reporting coverage.when the room is not in use, for example, during vacations. All periods still offer a higher detection reliability of a covered detector compared to the standardized situation of a visual inspection. If there are two or more detectors in a room, one of which detects fluctuations but the other does not, it can be assumed with a high degree of probability thatthat the detector is covered without fluctuations. In this case, a service notification or technical information can be issued immediately. In all other cases, if there are no fluctuations in the selected monitoring period, the detectors are entered into a list by the system, and an error message is not necessarily required. The following options are available for evaluating the detectors entered in the list without fluctuations: • The list can be viewed via remote maintenance. The responsible person decides on the further procedure. • The detectors are checked as soon as possible during guard patrols or other inspections, and if coverage is actually detected, they are repaired accordingly. • During the annual inspection, only those detectors from the list for which no fluctuations were detected are visually inspected. All others are considered OK. • The system can be configured so thatthat the listed detectors are reported spontaneously or at certain times by the system as a technical notification. Although the method of thermal smoke entry monitoring depends on fluctuations in the room, which are not always present, it can be assumed with a high degree of certainty that smoke entry is impeded if no fluctuations are measurable. Furthermore, after a certain monitoring period (> 1 year), rooms can be identified as a precautionary measure where no fluctuations occur. These rooms can then be subjected to normal visual inspection. In general, the term "room" is synonymous with the term "location" (this includes, for example, installations in a suspended ceiling). Since thermal smoke entry monitoring is cost-neutral to implement, at least for most fire detectors,This method is suitable in addition to other methods such as optical smoke entry control or grille monitoring. Figure 7 shows an exemplary maintenance system WS for one or more exemplary fire detectors M1 - M3 according to the invention. The correspondingly configured fire detectors are described in Figures 1 to 6. The maintenance system WS for fire detectors M1 - M3 is advantageously installed in one or more fire compartments (e.g. rooms, zones in a building), with each fire detector M1 - M3 being configured to record at least one fire characteristic in a detected fire situation, with the fire detector M1 - M3 having a housing G with at least one inlet opening OF, a sensor system communicating with the ambient air via this inlet opening for detecting a flow in the area of the sensor system, and a control unit MC (see Figure 3).- wherein the control unit MC is connected to the sensor system for evaluating the operational capability of the fire detector M1 - M3, - wherein the sensor system comprises at least one thermistor T1-T4, in particular at least one NTC, arranged in the region of at least one of the inlet openings OF, as an example of a temperature sensor for measuring thermal fluctuations, - wherein the control unit MC is connected to the at least one thermistor T1-T4 for detecting a respective temperature measurement signal S1-S4, and - wherein the control unit MC is further configured to detect whether or not thermal fluctuations exist in the inlet opening OF, - wherein the control unit MC is further configured, in the event that no thermal fluctuations are detected, to enter a corresponding message into a memory (e.g., database, list) of an evaluation unit AE of the maintenance system WS. FIG. 7 shows an exemplary detector line ML,with fire detectors M1 – M3 according to the invention. The fire detectors M1 – M3 are assigned, for example, to a specific fire compartment (e.g., room, zone) in a building, i.e., they are arranged in this fire compartment. If a fire detector M1 – M3 detects that there is no thermal fluctuation in the area of its entry opening, it sends a "No Fluctuation" KFL (par) message. The "No Fluctuation" KFL (par) message can be sent via the ML detector line to a fire alarm control panel BMZ (e.g., panel), and from the fire alarm control panel BMZ to the evaluation unit AE via a suitable communication connection KV1. The "No Fluctuation" KFL (par) message can also be sent directly from the detectors M1 – M3 to the evaluation unit AE via a suitable communication connection KV2. Advantageously, a "No Fluctuation" message includes KFL (par) parameters and / or metadata and / or attributes, such as information about the fire detector, information about the installation location,Information about the fire compartment, or information about the time or period during which no fluctuations are detected. The parameters can also include information about the installation (e.g., time of installation, installer, test data). The parameters can also include information about the last maintenance. The communication connections KV1, KV2 can be implemented, for example, using suitable radio connections (e.g., WLAN). The evaluation unit AE is implemented, for example, as a rule engine or as an AI engine based on appropriately trained neural networks. The evaluation unit AE can also be based on appropriate decision tables. The evaluation unit AE can be based on machine learning methods. The evaluation unit AE is, for example, implemented in an appropriately configured server S with appropriate processing, communication,Input / output and storage resources are implemented. The evaluation unit AE and the server S are advantageously implemented in a cloud infrastructure (CLOUD). The server S stores the "No Fluctuation" KFL (par) messages and the evaluation results of the evaluation unit AE in a storage DB (e.g., database). The KFL (par) messages and the evaluation results are advantageously stored in a building information model (BIM). The server S is advantageously configured to send corresponding SM messages to a building control center and / or a facility management system (FM) based on the evaluation results of the evaluation unit AE. The maintenance system is advantageously configured so that the detection of thermal fluctuations in the control unit (MC) occurs by evaluating the signal bandwidth of the signal fluctuations, whereby the message that no thermal fluctuations were detectedbe entered into the memory DB of the evaluation unit AE if the signal bandwidth of signal fluctuations of at least one of the recorded, preferably all, temperature measurement signals (S1-S4) falls below a value of 30 mK, in particular 20 mK, preferably 15 mK, for a minimum time (MZ). Advantageously, the evaluation unit AE is configured such that, after evaluating the KFL (par) messages entered into the memory DB, upon detection that no fluctuation is present, a service message SM is issued if the evaluation indicates a lack of fluctuation in a fire compartment. Advantageously, the messages entered into the memory DB in a defined monitoring interval are classified with regard to the number of messages and / or the respective installation location of the detectors that do not report any fluctuation.evaluated by the evaluation unit AE. The defined monitoring interval can be, for example, one day, one month, or one year. The memory DB of the server S can advantageously be read via cloud access and / or internet access and / or remote maintenance. In the event of an inspection, particularly an annual inspection, only those fire detectors are checked for which no fluctuations were detected. A service message SM is advantageously issued if two or more fire detectors M1 – M3 are located in a fire compartment, particularly in a room, and one of them detects fluctuations.the other, however, is not. FIG. 8 shows an exemplary flowchart for a method for servicing fire detectors according to the invention. The method is particularly suitable for detecting contamination or an impermissible covering of at least one inlet opening for smoke or fire gas in a fire detector. The method comprises the following steps: - (VS1) wherein at least one unheated thermistor is arranged in the region of one of the inlet openings, - (VS2) wherein a temperature measurement signal is recorded by the respective thermistor, - (VS3) wherein a message for the absence of moving ambient air around the at least one thermistor is entered into the memory of an evaluation unit, and - (VS4) wherein the evaluation unit issues a service message after evaluating the messages entered into the memory (e.g., database, list, BIM) that there is no fluctuation.if the evaluation indicates a lack of fluctuation in a fire compartment. The message for the absence of moving ambient air around the at least one thermistor is advantageously generated when the signal bandwidth of signal fluctuations of at least one of the detected, preferably all, temperature measurement signals falls below a value of 30 mK, in particular 20 mK, preferably 15 mK, for a minimum period of time. The messages entered into the memory (database, list) in a defined monitoring interval are advantageously analyzed by the evaluation unit with regard to the number of messages and / or the respective installation location of the detectors that report no fluctuation to determine whether the evaluation indicates a lack of fluctuation in a fire compartment. The defined monitoring interval can be, for example, one day, one month, or one year. The memory (e.g., database,List) is read by the evaluation unit via on-premises access and / or via cloud access and / or via internet access and / or via remote maintenance. Advantageously, in the case of a maintenance inspection, particularly during an annual maintenance inspection, only those fire detectors are checked for which no fluctuations were detected. Advantageously, the evaluation unit issues a service message if there are two or more fire detectors in a fire compartment, particularly in a room, of which at least one of the fire detectors is not reporting any fluctuations. In summary, the invention relates to a maintenance system and a method for maintaining fire detectors, particularly for detecting contamination or an impermissible covering of at least one inlet opening for smoke or fire gas in a fire detector.- wherein at least one preferably unheated temperature sensor is arranged for measuring thermal fluctuations in the region of one of the inlet openings, - wherein a temperature measurement signal is detected by the respective temperature sensor, - wherein a message for the absence of moving ambient air around the at least one temperature sensor is entered into the memory of an evaluation unit, and - wherein the evaluation unit, after evaluating the messages entered into the memory (database, list, BIM) that no fluctuation is present, issues a service message if the evaluation indicates a lack of fluctuation in a fire compartment.
[0002] Reference symbol A Main axis, symmetry axis ADC A / D converter AL Fire alarm, alarm AVS Moving arithmetic mean filter B / 2 half signal bandwidth BZM Operating timer BZW Operating time measured value COV Covering message DET Evaluation unit D1-D4 Digital temperature measurement signal F H1-F H4 Hochpassfiltersignal F O1 -F O4Filter output signals FZ Filter time GG Base body GW Limit value H Hood, detector hood HP High-pass filter LED Light transmitter, light-emitting diode M, M1 – M3 Fire detector, smoke detector MC Electronic control unit, microcontroller MK Fire detection unit, optical measuring chamber MZ Minimum time N Insect screen, mesh OF Inlet opening, smoke inlet opening PCB Circuit carrier PD Light receiver, photodiode PRG Computer program, software RMS Sliding square mean filter S1-S4 Temperature measurement signal t Time, time axis T1-T4 Thermistor, NTC TIMER Timer, time measuring element TP Low-pass filter WM Warning message, contamination message WZ Minimum waiting time ^ ^ Temperature change ^ Temperature VS1 – VS4 Process step WS Maintenance system S Server AE Evaluation unit DB Memory BIM Building information model CLOUD Cloud infrastructure BMZ Fire alarm control panel ML Detector line KV1, KV2 Communication connection KFL (par) No fluctuation message FM Facility management SM Service message
Claims
1. Maintenance system (WS) for fire detectors (M1 - M3), installed in one or more fire compartments, wherein each fire detector (M1 - M3) is configured to detect at least one fire characteristic in a detected fire, wherein the fire detector (M1 - M3) has a housing (G) with at least one inlet opening (OF), a sensor system communicating with the ambient air via this inlet opening for detecting a flow in the region of the sensor system, and a control unit (MC), - wherein the control unit (MC) is connected to the sensor system for evaluating the operational capability of the fire detector (M), - wherein the sensor system has at least one temperature sensor (T1-T4) arranged in the region of at least one of the inlet openings (OF) for measuring thermal fluctuations, in particular at least one thermistor,- wherein the control unit (MC) is connected to the at least one temperature sensor (T1-T4) for detecting a respective temperature measurement signal (S1-S4), and - wherein the control unit (MC) is further configured to detect whether or not thermal fluctuations exist in the inlet opening (OF), - wherein the control unit (MC) is further configured, in the event that no thermal fluctuations are detected, to enter a corresponding message (KFL (par)) into a memory (DB) of an evaluation unit (AE) of the maintenance system (WS).
2. Maintenance system (WS) according to claim 1, wherein the detection of thermal fluctuations in the control unit (MC) is carried out by evaluating the signal bandwidth of signal fluctuations, wherein the message (KFL (par)) that no thermal fluctuations were detected is entered in the memory (DB) of the evaluation unit (AE) if the signal bandwidth of signal fluctuations of at least one of the detected,preferably all temperature measurement signals (S1-S4), falls below a value of 30 mK, in particular 20 mK, preferably 15 mK, for a minimum time (MZ).
3. Maintenance system (WS) according to one of the preceding claims, wherein the evaluation unit (AE) issues a service message (SM) after evaluating the messages (KFL (par)) entered in the memory (DB) that no fluctuation is present if the evaluation indicates a lack of fluctuation in a fire compartment.
4. Maintenance system (WS) according to claim 3, wherein the messages (KFL (par)) entered in the memory (DB) in a defined monitoring interval are evaluated by the evaluation unit (AE) with regard to the number of messages and / or with regard to the respective installation location of the detectors that report no fluctuation.
5. Maintenance system (WS) according to claim 4, wherein the defined monitoring interval is one day, one month, or one year. 6.Maintenance system (WS) according to one of the preceding claims, wherein the memory (DB) of the evaluation unit (AE) is readable via cloud access and / or via internet access and / or via remote maintenance.
7. Maintenance system (WS) according to one of the preceding claims, wherein in the event of an inspection, in particular during an annual inspection, only those fire detectors (M1 - M3) are checked for which no fluctuations were detectable.
8. Maintenance system (WS) according to one of the preceding claims, wherein a service message (SM) is issued if there are two or more fire detectors in a fire compartment, in particular in a room, of which one fire detector detects fluctuations but the other does not.
9. Maintenance system (WS) according to one of the preceding claims, wherein the maintenance system (WS), in particular the evaluation unit, is implemented in a cloud infrastructure (CLOUD). 10.Method for the maintenance of fire detectors, in particular for the detection of contamination or an impermissible covering of at least one inlet opening (OF) for smoke or fire gas in a fire detector (M), - (VS1) wherein at least one temperature sensor (T1-T4), in particular at least one thermistor, is arranged to measure thermal fluctuations in the region of one of the inlet openings (OF), - (VS2) wherein a temperature measurement signal (S1-S4) is detected by the respective temperature sensor (T1-T4), - (VS3) wherein a message for the absence of moving ambient air around the at least one temperature sensor (T1-T4) is entered into the memory of an evaluation unit, and - (VS4) wherein the evaluation unit, after evaluating the messages (KFL (par)) entered into the memory (database, list, BIM) that no fluctuation is present, issues a service message (SM) if the evaluation indicates a missing Fluctuation in a fire compartment. 11.Method according to claim 10, wherein the message (KFL (par)) for the absence of moving ambient air around the at least one temperature sensor (T1-T4) is generated when the signal bandwidth of signal fluctuations of at least one of the detected, preferably all, temperature measurement signals (S1-S4) falls below a value of 30 mK, in particular 20 mK, preferably 15 mK, for a minimum time (MZ).
12. Method according to claim 10 or 11, wherein the messages entered into the memory (DB) in a defined monitoring interval are analyzed by the evaluation unit with regard to the number of messages and / or with regard to the respective installation location of the detectors that do not report any fluctuation. are used to determine whether the evaluation indicates a lack of fluctuation in a fire compartment.
13. The method according to one of claims 10 to 12, wherein the defined monitoring interval is one day, one month, or one year.
14. The method according to one of claims 10 to 13, wherein the memory (DB) is read from the evaluation unit (AE) via on-premise access and / or via cloud access and / or via internet access and / or via remote maintenance.
15. The method according to one of claims 10 to 14, wherein in the case of a maintenance inspection, in particular during an annual maintenance inspection, only those fire detectors are checked for which no fluctuations were detectable.Method according to one of claims 10 to 15, wherein a service message (SM) is output by the evaluation unit (AE) if two or more fire detectors are located in a fire compartment, in particular in a room, of which at least one of the fire detectors does not report any fluctuations.