Fire alarm device for detecting and reporting a fire and method for testing the function of the fire alarm device

Abstract

Fire alarm device (1) for detecting and reporting a fire, with a sensor (3) and with a measuring range, wherein the sensor system (3) is designed to detect the fire on the basis of a fire-specific environmental variable (8) in the measuring area, wherein the sensor system (3) is designed to output sensor signals (9) which are based on the fire-specific environmental variable (8), with a test unit (10) which is designed to emit a test gas (11) into the measuring area, wherein the test gas (11) simulates the fire-specific ambient variable (8) in the measuring area, with an evaluation unit (12) which is designed to evaluate the sensor signals (9) as measured values ​​(X), wherein the evaluation unit (12) is designed to evaluate the measured values ​​(X) over a period of time (Z) as a measured value curve (M1; M2) and to check the functionality of the fire alarm device (1) by means of this evaluation, wherein the measuring area is formed by a measuring chamber (4) which comprises at least one opening (6) to the environment (7), wherein the test unit (10) introduces the test gas (11) into the measuring chamber (4), characterized in that the evaluation unit (12) is designed to evaluate the measured values ​​(X) over the period (Z) as a decay measured value curve (M1; M2) and to check by this evaluation whether the at least one opening (6) of the measuring chamber (4) is free or at least partially blocked.

Description

[0001] The invention relates to a fire alarm device for detecting and reporting a fire, wherein the fire alarm device comprises a sensor system and a measuring range. The sensor system is designed to detect the fire based on a fire-specific environmental variable in the measuring range. It is designed to output sensor signals based on the fire-specific environmental variable. The fire alarm device comprises a test unit designed to output a test gas into the measuring range. The test gas simulates the fire-specific environmental variable in the measuring range. The fire alarm device comprises an evaluation unit designed to evaluate the sensor signals as measured values. The invention also relates to a method for functional testing of the fire alarm device.

[0002] DE 10 2010 031 139 A1 discloses a fire alarm device with a sensor system for detecting fire emissions and with a test device for emitting a test gas to perform a functionality test. DE 10 2009 046 556 A1 discloses a fire alarm device with at least one sensor system for detecting at least one fire-specific ambient variable in a sensor detection range, with at least one test device that has a gas reservoir for a test gas. WO 02 / 027 293 A2 discloses a gas detector or a heat detector that comprises a test device that is operatively connected to the gas detector or the heat detector. State of the art

[0003] Smoke detectors are known from the prior art that include a test gas generator for generating a test gas. When the test gas is generated in a sensor detection zone of the fire alarm device, the functionality of the fire alarm device is checked.

[0004] For example, the publication DE 10 2009 046 556 A1, which arguably represents the closest prior art, describes a fire alarm device with a test device. The fire alarm device has a sensor system for detecting a fire-specific ambient variable in a sensor detection area. It includes a test device for releasing a test gas into the sensor detection area so that the test gas simulates the fire-specific ambient variable. During a functionality test of the fire alarm device, the test device is activated to release the test gas so that it reaches the sensor detection area, and the sensor system then detects a simulated fire. Disclosure of the invention

[0005] A fire alarm device having the features of claim 1 and a method for functional testing of the fire alarm device having the features of claim 11 are proposed. Preferred and / or advantageous embodiments of the invention emerge from the subclaims and / or the following description.

[0006] A fire alarm device for detecting and reporting a fire is proposed. The fire alarm device comprises a sensor system and a measuring range, wherein the sensor system is designed to detect the fire based on a fire-specific environmental variable in the measuring range and to output sensor signals. The sensor signals are based on the fire-specific environmental variable.

[0007] The fire-specific environmental variable preferably comprises a fire gas or smoke gas with solid particles or an aerosol with liquid suspended particles. The solid particles can include, for example, soot particles, and the liquid particles can include, for example, water droplets.

[0008] The fire alarm device comprises a test unit, which is preferably fluidically connected to the measuring area. The test unit is designed to emit a test gas into the measuring area. The test unit preferably generates the test gas and / or emits it into the measuring area. The test gas simulates the fire-specific ambient variables in the measuring area. In particular, the test gas comprises the fire or smoke gas with the solid particles and / or the aerosol with the liquid suspended particles.

[0009] The fire alarm device comprises an evaluation unit designed to evaluate the sensor signals as measured values. According to the invention, the evaluation unit is designed to evaluate the measured values ​​over a period of time as a measured value curve and thereby check the functionality of the fire alarm device.

[0010] The invention has the advantage that the fire alarm device can be remotely tested using the integrated test unit. In particular, the fire alarm device and the test unit form a single structural unit, allowing the fire alarm device to be tested for functionality, for example, by remote control. This saves travel costs, working time, and personnel.

[0011] Another advantage is that the possibility of remote testing allows fire alarm devices located in restricted areas, such as a nuclear power plant, or in hard-to-reach places such as suspended ceilings or high ceilings to be quickly and easily tested for functionality. In particular, costs and time associated with the use of additional equipment, such as lifting platforms, can be saved.

[0012] According to the invention, the measuring area is formed by a measuring chamber. The measuring chamber comprises at least one opening to the environment. In one possible embodiment of the invention, the test unit introduces the test gas through the at least one opening into the measuring chamber. Thus, the fire-specific ambient variable simulated by the test gas, or the fire-specific ambient variable generated during a real fire, can penetrate through the opening into the measuring chamber, where it is detected by the sensors, and the sensor signals are output. By evaluating the sensor signals as measured values, the evaluation unit can detect the simulated or real fire, whereupon the control unit controls the signal generator to output the warning signal and thus report the fire.

[0013] In a preferred embodiment of the invention, the measuring chamber comprises at least one test gas inlet through which the test unit introduces the test gas into the measuring chamber. It is preferred that the test unit introduces or releases the test gas directly and without loss through the test gas inlet into the measuring chamber. This eliminates the need for complex and space-consuming test gas lines in the fire alarm device.

[0014] A further advantage is that the direct and loss-free introduction of the test gas into the measuring chamber allows a precise amount of test gas to be introduced into the measuring chamber, thus enabling reliable calibration of the fire alarm device. Since the amount of test gas introduced into the measuring chamber by the test unit is precisely known, it is possible to determine the sensitivity of the fire alarm device. This could avoid the need for blanket replacement of the fire alarm device after eight years. Avoiding blanket replacement of the fire alarm device after eight years advantageously avoids unnecessary costs for replacing fully functional fire alarm devices. Furthermore, the environment can be protected because the demand for newly manufactured fire alarm devices is reduced, thus saving resources for their production.

[0015] If the fire alarm device is to be tested for its functionality, preferably remotely, the test unit is preferably controlled by remote control to release or introduce the test gas into the measuring chamber.

[0016] Preferably, the test gas in the measuring chamber simulates the fire-specific ambient variable. In particular, the sensor system detects the simulated fire based on the simulated fire-specific ambient variable in the measuring chamber and outputs the sensor signals, which are then evaluated by the evaluation unit as a temporal measured value curve. By evaluating the temporal measured value curve, it can be tested and verified whether at least one opening of the measuring chamber to the environment is unobstructed or whether it is at least partially blocked. In particular, it can be verified whether any smoke or combustion gas or aerosol generated by a real fire can penetrate the measuring chamber at all or whether the at least one opening is blocked.

[0017] This check is particularly important because a blockage of at least one opening negatively impacts the functionality of the fire alarm system. In particular, if the opening is blocked, the smoke or fire gases generated by the actual fire cannot enter the measuring chamber and thus cannot be detected by the sensors. In this case, the fire cannot be detected by the fire alarm system, significantly increasing the danger to people in the surrounding area.

[0018] According to the invention, the evaluation unit evaluates the measured values ​​over the period as a decaying measured value curve. Preferably, the measured values ​​of the decaying measured value curve decrease continuously within the curve. By evaluating the values ​​as a temporal decaying measured value curve, the evaluation unit checks whether at least one opening of the measuring chamber is clear or at least partially blocked.

[0019] In a preferred implementation of the invention, the measured value curve depends on the intensity with which the sensor system (sensor unit) detects scattered light. This is particularly the case when the fire alarm device is designed as an optical or photoelectric smoke detector. This typically operates according to the scattered light method (Tyndall effect). The optical or photoelectric smoke detector preferably has an infrared diode (LED) that emits a test light beam into the measuring chamber. The sensor unit preferably comprises at least one photodiode for detecting scattered light.

[0020] If there are no fire-specific ambient variables in the measuring chamber, especially no fire or smoke gases containing soot particles or no aerosol containing liquid particles, the light is practically not scattered. However, if such particles are present in the measuring chamber and the test light beam emitted by the infrared diode hits them, the light is scattered and detected by the sensor unit, which is designed as a photodiode.

[0021] As the test gas escapes through the opening of the measuring chamber, the scattered light is detected by the sensor unit, preferably with a steadily decreasing intensity, since there are fewer and fewer particles in the measuring chamber and therefore less and less light is reflected. The escape of particles through the opening therefore results in a decreasing number of emitted sensor signals and thus a decaying measurement value curve.

[0022] Alternatively, especially if the fire alarm device is designed as an ionization smoke detector, the measured value curve depends on the current detected by the sensor unit. In this case, the sensor unit is designed as a measuring device for detecting the current.

[0023] Ionization smoke detectors typically have a radioactive emitter for emitting alpha rays. The ionization smoke detector consists of two spaced-apart charged metal plates as electrodes. Ions are formed between the plates by the alpha rays, causing a current to flow between the electrodes. When the surrounding fire-related particles, particularly soot or liquid particles, pass between the electrodes, they capture some of the ions due to electrostatic attraction.

[0024] The current strength is therefore dependent on the quantity or concentration of particles in the measuring chamber, with an increased number of particles causing a decrease in the current strength, which is detected by the sensor unit. In contrast, the sensor unit preferably detects an increase in the current strength when the particles gradually escape from the at least one opening of the measuring chamber.

[0025] The evaluation unit can therefore use the sensor signals based on the current strength and their evaluation as a temporal measured value curve to determine the number or concentration of particles in the measuring chamber.

[0026] In a preferred embodiment of the invention, the evaluation unit evaluates a decrease in the measured value curve, in particular the decay of the measured value curve, over a period of time based on a threshold value. The threshold value preferably forms a comparison value that determines by how much the number or concentration of particles in the measuring chamber must decrease to a certain value within the period of time in order for the at least one opening of the measuring chamber to be recognized as free or unblocked.

[0027] If a decay measurement curve is evaluated but it shows that the number or concentration of particles in the measuring chamber has only decreased by a small amount or less than the threshold value within the specified period, this indicates a partially blocked opening of the measuring chamber.

[0028] If no decaying measured value curve is evaluated, but instead, for example, a measured value curve that is largely the same over the period, this indicates a complete blockage of at least one opening of the measuring chamber.

[0029] If the evaluation unit detects a partially or completely blocked opening by evaluating the measured value curve based on the threshold value, the control device preferably controls the signal generator or another signal generator to emit a warning signal indicating the blocked opening. The signal can be, for example, an optical signal or an audio signal.

[0030] It is particularly preferred that the test gas comprises a smoke or combustion gas, and that the test unit comprises a combustion gas or smoke generator. For example, the test unit comprises an electric heating element coated with plastic, whereby the smoke gas is generated by heating the plastic.

[0031] Alternatively or optionally in addition, the test gas comprises an aerosol and the test unit comprises a device for vaporizing or nebulizing a liquid, in particular an oil or chemical specially selected for smoke simulation.

[0032] Another object of the invention relates to a method for functional testing of the fire alarm device according to one of claims 1 to 10 and / or according to the previous description. Within the method, the evaluation unit evaluates the time at which the test gas escapes from the measuring area.

[0033] Further features, advantages, and effects of the invention will become apparent from the following description of preferred embodiments of the invention. These show: Fig. 1 a schematic block diagram of a fire alarm device with a measuring chamber; Fig. 2 shows a temporal decay of the measured values ​​with a free and a partially blocked opening of the measuring chamber Fig. 1.

[0034] Corresponding or identical parts are provided with the same reference numerals in the figures.

[0035] Fig. 1 shows a fire alarm device 1 in a schematic block diagram as an embodiment of the invention.

[0036] The fire alarm device 1 is designed as an optical or photoelectric smoke detector or as an ionization smoke detector to be mounted on a room ceiling or wall and to detect and report a fire in the area 7 of the smoke detector.

[0037] As an optical or photoelectric smoke detector, the fire alarm device 1 has, for example, an infrared diode for generating a test light beam and a photodiode as a sensor 3 for detecting scattered light. Clear air reflects practically no light, so no scattered light is generated. However, if a fire-specific environmental variable 8, e.g., smoke gas with soot particles generated by the fire, is present in the air, these reflect the test light beam and generate the scattered light. Based on the scattered light, the fire in the vicinity 7 of the optical or photoelectric smoke detector can be detected, and an alarm can be triggered.

[0038] In the form of an ionization smoke detector, the fire alarm device 1 comprises a radioactive emitter and two charged metal plates as electrodes. The emitter generates alpha or beta radiation, which irradiates and ionizes a volume of air between the electrodes. The generation of ions in the air causes a current to flow between the electrodes. If the fire-specific ambient quantity 8, e.g. the smoke gas with the soot particles, is present in the air, the ions collide with the soot particles and settle there. This reduces the conductivity of the air and thus the current flow. If the current flow decreases, it is concluded that there is a fire in the environment 7 of the ionization smoke detector, and the ionization smoke detector reports the fire.

[0039] To report a fire, the fire alarm device 1 preferably comprises a signaling device 2 for emitting an acoustic and / or visual alarm signal. Alternatively or optionally, the signaling device 2 can comprise an interface to a fire alarm control panel and output the alarm signal there.

[0040] The fire alarm device 1 has a sensor system 3 and a measuring area designed as a measuring chamber 4. The measuring chamber 4 has a test gas inlet 5 and several openings 6 to the environment 7 of the fire alarm device 1.

[0041] If a fire in the environment 7 generates the fire-specific environmental variable 8, e.g. the smoke gas with the soot particles or aerosol with liquid particles, this can flow into the measuring chamber 4 through the openings 6 and also escape from the measuring chamber 4 through these openings.

[0042] The sensor system 3 detects the fire based on the fire-specific environmental variable 8 in the measuring chamber 4 and outputs sensor signals 9 based on the fire-specific environmental variable 8. For this purpose, it comprises, for example, at least one photodiode for detecting scattered light generated, for example, by the soot particles if the fire alarm device 1 is designed as an optical or photoelectric smoke detector.

[0043] In the design of the fire alarm device 1 as an ionization smoke detector, the sensor system 3 comprises at least one measuring device for measuring the current strength between the electrodes.

[0044] The fire alarm device 1 has a test unit 10. The test unit 10 comprises a smoke gas generator or a vaporizer or nebulizer for dispensing liquid, in particular for generating a test gas 11. The test unit 10 is fluidly connected to the measuring chamber 4 and introduces the test gas 11 therein. It is preferred that the test gas 11 be dispensed directly, i.e., without detours via lines, etc., by the test unit 10 into the measuring chamber 4.

[0045] The test gas 11 introduced into the measuring chamber 4 simulates the fire-specific ambient variable 8 in the measuring chamber 4. Thus, the fire alarm device 1 can be checked for functionality.

[0046] On the one hand, by introducing the test gas 11 into the measuring chamber 4, it is checked whether the fire alarm device 1 detects and reliably reports a fire based on the fire-specific environmental variable 8 in the measuring chamber 4.

[0047] Secondly, by introducing the test gas 11 into the measuring chamber 4, it can be determined whether the openings 6 to the environment 7 are free and sufficiently permeable, or whether they are partially or even completely blocked. This check is important because, if the openings 6 are at least partially blocked, the fire or smoke gas or aerosol generated by a real fire cannot penetrate the measuring chamber 4, or cannot penetrate it in sufficient concentration, and the fire alarm device 1 therefore cannot detect and report the real fire.

[0048] The fire alarm device 1 comprises an evaluation unit 12 and a control unit 13, wherein the evaluation unit 12 evaluates the sensor signals 9 based on the fire-specific environmental variable as measured values ​​X. If the evaluation unit 12 detects the fire based on the measured values ​​X, the control unit 13 controls the signal generator 2 to output the warning signal.

[0049] The evaluation unit 12 also evaluates the measured values ​​X as a temporal measured value curve M1; M2 ( Fig. 2) and thereby checks the functionality of the fire alarm device 1. In particular, the evaluation unit 12 checks, based on a temporal decay of measured values ​​M1; M2, whether the openings 6 to the environment 7 are free or at least partially blocked.

[0050] If the evaluation unit 12 detects an at least partial or complete blockage of the openings 6, the control unit 13 controls the signal generator 2 or another signal generator to emit an indication signal 14 indicating the blocked openings 6. The indication signal 14 can be output as an optical and / or acoustic signal.

[0051] In Fig.2 shows a diagram with two curves, in particular two exemplary temporal measured value curves M1; M2, wherein a first temporal measured value curve M1 is recorded when the openings 6 of the measuring chamber 4 are completely free. A second temporal measured value curve M2 is recorded when the openings 6 of the measuring chamber 4 are partially blocked. Both measured value curves M1; M2 are evaluated by the evaluation unit 12 as decay measured value curves M1; M2.

[0052] On the Y-axis of the diagram, a quantity or concentration of the fire-specific environmental variable 8 simulated by the test gas 11, in particular the fire or smoke gas with the soot particles and / or the aerosol with the liquid particles, is plotted in the measuring chamber 4.

[0053] The X-axis represents a timeline over which the measured values ​​X are evaluated as the temporal measured value curves M1; M2.

[0054] The evaluation unit 12 evaluates the measured value curves M1; M2 based on a threshold value S. The threshold value S indicates a comparison value by how much the quantity or concentration of the fire-specific ambient variable 8 must have decreased within a period of time (Z) in the measuring chamber 4 for the openings 6 to be recognized as clear. Thus, the temporal decrease of the measured value curves M1; M2 is measured and evaluated as a function of the threshold value S.

[0055] The two curves show that the threshold value S is reached after a period of time delta t in the first decay measurement curve M1, whereas the threshold value S is only reached after a period of time delta t* in the second decay measurement curve M2.

[0056] By evaluating the first decay measured value curve M1, the evaluation unit 12 recognizes that the openings 6 of the measuring chamber are free, since the fire-specific ambient variable 8, in particular the fire or smoke gas with the soot particles and / or the aerosol with the liquid particles, can escape from the measuring chamber 4 in a sufficiently short time (delta t).

[0057] When evaluating the second decay measured value curve M2, the evaluation unit 12 determines that the openings 6 are at least partially blocked, since the fire-specific ambient variable 8 escapes from the measuring chamber 4 significantly more slowly, namely within the period delta t*.

[0058] When the second decay measurement value curve M2 is evaluated by the evaluation unit 12, the control unit 13 controls the signal generator 2 or the further signal generator to output the indication signal 14, which indicates the blocked openings 6.

[0059] As an alternative to this evaluation method, it is possible to assume the decay measurement curve M1 or M2 as an exponential behavior of the smoke density curve and to approximate the curve to the following equation: R(t)=A*exp(−kt)

[0060] With: R Smoke density T Time A Initial smoke density k decay parameters

[0061] By testing the initial smoke density A against a reference value, the smoke generator can also be tested for its functionality. The decay parameter k describes the decay behavior of the smoke density. If the measured or approximated value for k is smaller than a threshold value, it can be concluded that the opening 6 of the measuring chamber 4 is at least partially closed, and the warning signal 14 is emitted.

[0062] As a further alternative, it is possible to determine a gradient across multiple measurement points (>3), e.g., using linear regression. If the gradient is smaller than a threshold value, it can be concluded that the opening 6 of the measuring chamber 4 is at least partially closed, and the warning signal 14 is emitted.

[0063] When the fire alarm device 1 is designed as an optical or photoelectric smoke detector, the measured value curve M1; M2 depends on the intensity of the scattered light detection by the sensor system 3 and the resulting sensor signal output. The intensity of the scattered light, in turn, depends on the quantity or concentration of the fire-specific environmental variable 8, in particular the soot particles and / or liquid particles in the measuring chamber 4. The higher the quantity or concentration of the fire-specific environmental variable 8, the more intensively the scattered light is detected by the sensor system 3. Thus, the intensity of the scattered light detection can be used to determine the quantity or concentration of the fire-specific environmental variable 8, and to evaluate whether the openings 6 of the measuring chamber are clear or at least partially blocked.

[0064] When the fire alarm device 1 is configured as an ionization smoke detector, the measured value curve depends on the current intensity detected by the sensor system 3. This, in turn, depends on the quantity or concentration of the fire-specific environmental variable 8, in particular the soot particles and / or liquid particles in the measuring chamber 4. The higher the quantity or concentration of the fire-specific environmental variable 8, the lower the current intensity. Thus, the current intensity curve can be used to infer a decrease in the quantity or concentration of the fire-specific environmental variable 8 in the measuring chamber and to determine whether the openings are clear or at least partially blocked.

Claims

[1] Fire alarm device (1) for detecting and reporting a fire, with a sensor (3) and with a measuring range, wherein the sensor system (3) is designed to detect the fire on the basis of a fire-specific environmental variable (8) in the measuring area, wherein the sensor system (3) is designed to output sensor signals (9) which are based on the fire-specific environmental variable (8), with a test unit (10) which is designed to emit a test gas (11) into the measuring area, wherein the test gas (11) simulates the fire-specific ambient variable (8) in the measuring area, with an evaluation unit (12) which is designed to evaluate the sensor signals (9) as measured values ​​(X), wherein the evaluation unit (12) is designed to evaluate the measured values ​​(X) over a period of time (Z) as a measured value curve (M1; M2) and to check the functionality of the fire alarm device (1) by means of this evaluation, wherein the measuring area is formed by a measuring chamber (4) which comprises at least one opening (6) to the environment (7), wherein the test unit (10) introduces the test gas (11) into the measuring chamber (4), characterized by , that the evaluation unit (12) is designed to evaluate the measured values ​​(X) over the period (Z) as a decay measured value curve (M1; M2) and to check by this evaluation whether the at least one opening (6) of the measuring chamber (4) is free or at least partially blocked. [2] Fire alarm device (1) according to claim 1, characterized by that the measuring chamber (4) has at least one test gas inlet (5), wherein the test unit (10) introduces the test gas (11) through the test gas inlet (5) directly and without loss into the measuring chamber (4). [3] Fire alarm device (1) according to one of the preceding claims, characterized bythat the fire alarm device (1) is designed such that the measured value curve (M1; M2) is dependent on an intensity with which the sensor system (3) detects a scattered light. [4] Fire alarm device (1) according to claim 3, characterized by that the fire alarm device (1) is designed as an optical or photoelectric smoke detector, wherein the sensor system (3) comprises at least one photodiode for detecting the scattered light, wherein the sensor system (3) detects the scattered light with decreasing intensity and outputs the sensor signals (9) when the test gas (11) gradually escapes through the opening (6) of the measuring chamber (4). [5] Fire alarm device (1) according to one of the preceding claims, characterized by that the fire alarm device (1) is designed such that the measured value curve (M1; M2) is dependent on a current intensity detected by the sensor system (3). [6] Fire alarm device (1) according to claim 5, characterized bythat the fire alarm device (1) is designed as an ionization smoke detector, wherein the sensor system (3) comprises a measuring device for measuring the current intensity, wherein the sensor system (3) detects an increase in the current intensity and outputs the sensor signals (9) when the test gas (11) gradually escapes through the opening (6) of the measuring chamber (4). [7] Fire alarm device (1) according to one of the preceding claims, characterized by that the evaluation unit (12) is designed to evaluate a drop in the measured value curve (M1; M2) in the period (Z) on the basis of a threshold value (S). [8] Fire alarm device (1) according to one of the preceding claims, characterized by that the test gas (11) comprises a fire or smoke gas and the test unit (10) has a fire gas or smoke gas generator. [9] Fire alarm device (1) according to claim 8, characterized bythat the test unit (10) comprises an electrical heating element coated with plastic and generates the test gas (11) by heating the plastic. [10] Fire alarm device (1) according to one of the preceding claims, characterized by that the test gas (11) comprises an aerosol and the test unit (10) has a device for evaporating or nebulizing a liquid. [11] Method for functional testing of a fire alarm device (1) according to one of the preceding claims, characterized by that the evaluation unit (12) evaluates an escape of the test gas (11) from the measuring area over time, in that the evaluation unit (12) evaluates the measured values ​​(X) over the period (Z) as a decay measured value curve (M1; M2) and thereby checks whether at least one opening (6) of a measuring chamber (4) is free or at least partially blocked.

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