Monitoring device, in particular environmental monitoring, for a fire detector, as well as fire detector and auxiliary device, each with such a monitoring device.

Abstract

Monitoring device, in particular environmental monitoring, for a fire detector (10) for detecting objects in the vicinity of the fire detector (10), wherein the monitoring device (1) has a housing (2) with a mounting surface (BF) for at least indirect attachment to an opposite flat mounting surface (D), in particular to a ceiling, and wherein the monitoring device (1) has an electronic control unit (6) configured to output a warning message (W) and / or at least a distance information (AB) in the event of a detected object, characterized in that - that the monitoring device (1) has at least four time-of-flight sensors (3) arranged as a unit on a radial outer surface (RA) of the housing (2) with respect to an axis of symmetry (A) of the fire detector (10), which are preferably arranged uniformly in the circumferential direction (δ) to the axis of symmetry (A), - that the time-of-flight sensors (3) each have an optical detection cone (FOV) directed radially away from the axis of symmetry (A) with an associated optical axis (OA), wherein the respective detection cone (FOV) comprises a detection angle (β) in a range of 15° to 40°, in particular 20° to 35°, preferably 25° to 30°, wherein the optical axes (OA) are inclined to the axis of symmetry (A) by an inclination angle (α) dimensioned towards the mounting surface (BF), and wherein the following applies to the inclination angle α: α < 65° - ½ · β ∧ α > 55° - ½ · β ; - that the electronic control unit (6) is connected to the at least four time-of-flight sensors (3) via data transmission and is configured to receive distance information (AB, HIST) from the respective time-of-flight sensors (3) and to issue the warning message (W) if at least one of the received distance information (AB, HIST) falls below an assignable predefined distance value (DIST) around the fire detector (10).

Description

[0001] The invention relates to a monitoring device, in particular an environmental monitoring device, for a fire detector for detecting objects in the vicinity of the fire detector. The monitoring device comprises a housing with a mounting surface for at least indirect attachment to an opposing flat mounting surface, in particular a ceiling. The monitoring device has an electronic control unit which is configured or programmed to issue a warning message in the event of a detected object.

[0002] A fire detector is specifically a smoke detector, a smoke gas detector, or a smoke alarm. It can be an optical smoke detector or a multi-sensor smoke detector.

[0003] EP 1 857 989 A1 discloses a fire alarm with a housing and a self-testing device for checking the permeability of openings in the housing of the fire alarm, in which a sensor is provided for automating a visual inspection, scanning at least one opening optically and / or acoustically. According to one embodiment therein, a distance measurement in the area of ​​the opening can be carried out to scan the opening for testing its permeability. Preferably, this area also includes a region outside the fire alarm in front of the opening, which can still be detected by a distance sensor inside the fire alarm and preferably extends linearly from a center of the fire alarm through the opening to the outside of the fire alarm.This allows the proximity sensor to reliably monitor the area around the fire alarm, which is crucial for its functionality, either cyclically or on demand. If a predefined or adjustable minimum distance to an object is breached, a fault signal is generated. This ensures that obstructions such as covering, sticking, contamination, or blockage of the smoke inlet opening of the fire alarm can be reliably detected.

[0004] The article “VL53L0X and VL53L1X - ToF distance sensors” from the online magazine “Wolles Elektronikkiste”, https: / / wolles-elektronikkiste.de / v15310x-und-v15311x-tof-abstandssensoren, published on August 18, 2019, describes the measurement principle and the basic properties of Time-of-Flight distance sensors using the example of two ToF distance sensors VL53L0X and VL53L1X.

[0005] The document “1D Time-of-Flight Sensing” for the TMF8801 time-of-flight sensor from ams Sensors USA Inc., published in December 2018 at https: / / ams.com / documents / 20143 / 36005 / TMF8801_FS000238_1-00.pdf, describes the technical characteristics of the TMF8801 time-of-flight sensor and possible application examples.

[0006] From EP 2 348 495 A1, a smoke detector for enclosed spaces is known, featuring a housing that can be mounted on the ceiling or a wall of the room. A separate smoke chamber with smoke inlet openings is partitioned within the housing, containing measuring electronics that generate an evaluable measurement signal upon detection of smoke particles. At least one ultrasonic transceiver is arranged on the front of the detector such that it can emit ultrasonic signals into a defined monitoring area and receive reflected ultrasonic signals.

[0007] Such a monitoring device is known from German utility model DE 20 2018 003 266 U1.

[0008] European patent application EP 2 043 068 A1 discloses a device for monitoring a fire detector, which has a sensor sensitive to objects in the vicinity of the fire detector. The sensor is sensitive to objects located laterally to the side of the properly oriented fire detector within any arbitrary circular segment of 150° around the vertical. In one embodiment of the application, the distance of the fire detector to objects is determined by measuring the time of flight of radiation and by means of infrared radiation or other light.

[0009] Fire alarms can be rendered ineffective for rapid fire detection by blocking the smoke entry openings. This can happen unintentionally or even deliberately. Examples include covering the detector with foil or tape to protect it during painting or to prevent fire alarms triggered by cigarette smoke, such as in an airplane lavatory. Other examples include placing shelves or cabinets too close to the detector, or allowing large plants to grow towards it.

[0010] In commercial fire alarm systems, regular inspection of the system by a specialist is often required, one aspect of which is checking the fire detector for blockage of the smoke entry openings.

[0011] In residential buildings, periodic inspections are required, depending on state regulations. However, this poses a greater problem compared to commercial buildings due to accessibility issues. Since there are only a few fire detectors per apartment or house, the logistical effort required to schedule inspections for each detector is significantly higher than in large commercial buildings with numerous detectors but only one owner.

[0012] Furthermore, according to the standard DIN 14676-1:2018-12 "Smoke alarms for residential buildings, apartments and rooms with similar use - Part 1: Planning, installation, operation and maintenance", smoke alarms must be inspected at least once a year by means of a prescribed visual and functional test. The inspection includes, firstly, ensuring that there are no obstructions in the vicinity of the smoke alarm, such as within a radius of half a meter, which could impede the flow of smoke in the event of a fire. Secondly, if there are inlet openings in the housing of such an alarm, the permeability of these openings to smoke or flue gases must also be regularly checked. The inspection of such smoke alarms can also be automated.

[0013] According to the relevant DIN SPEC 91388 "Technical requirements for remotely inspectable smoke alarms," ​​the smoke alarm under test (test specimen) must be checked to determine whether it detects the lateral approach of a board (100 cm x 100 cm) oriented perpendicular to the test specimen at a distance of 50 cm ± 5 cm. This test must be repeated in 90° increments. These test requirements must be met for all four orientations. Additionally, the smoke alarm under test must be checked to determine whether it detects the approach of a board (100 cm x 100 cm) oriented perpendicular to the test specimen from below, towards the ceiling, at a distance of 50 cm ± 5 cm.

[0014] The fire detectors under consideration are preferably smoke detectors, smoke gas detectors, or smoke alarms. Such fire detectors typically have an optical detection unit operating on the scattered light principle for detecting smoke particles. The optical detection unit can be housed within the detector's casing, which has smoke inlet openings through which smoke to be detected can enter the casing and reach the optical detection unit. The detection unit preferably includes a labyrinth for shielding against direct ambient light. The fire detector can also be an open scattered light smoke detector with a scattered light volume located outside the detector's casing. Alternatively or additionally, the fire detectors can have a gas sensor for detecting gases typical of fires.

[0015] Furthermore, the fire detectors under consideration can be connected to a fire alarm control panel via a common detector line or circuit, in particular a two-wire line, for signal and / or data transmission. They can alternatively or additionally have an independent power supply, such as a battery. Furthermore, such fire detectors can have a radio module for transmitting an alarm message, a warning message, or status information to a neighboring fire detector or to a fire alarm control panel.

[0016] Based on this, one object of the present invention is to provide an improved monitoring device for a fire detector.

[0017] Another objective of the invention is to provide a fire detector with such a monitoring device.

[0018] These problems are solved by the subject matter of independent claim 1. Advantageous embodiments of the present invention are described in the dependent claims.

[0019] According to the invention, the monitoring device has at least three, preferably at least four, time-of-flight sensors arranged on a radial outer surface of the housing with respect to an axis of symmetry of the fire detector. The time-of-flight sensors are each designed as a single unit. They are preferably arranged uniformly distributed in the circumferential direction with respect to the axis of symmetry. A suitable time-of-flight sensor is, for example, the TMF8801 type from ams AG or the VL53L0X type from STMicroelectronics NV.

[0020] Time-of-flight sensors are used for optical time-of-flight measurement and thus for determining the distance to an object by emitting one or more light pulses and then measuring the time of flight of a light pulse reflected back from the object. Time-of-flight sensors have a light emitter, in particular an IR laser diode and preferably a surface-emitting laser diode, also known as a VCSEL (vertical-cavity surface-emitting laser). Such a VCSEL is a laser diode in which the light is emitted perpendicular to the plane of the semiconductor chip. The advantage of such a VCSEL lies in its highly efficient light generation combined with very high emitted light intensity. Furthermore, very short, steep-edged light pulses can be generated using such a VCSEL.

[0021] On the receiver side, time-of-flight sensors feature a photodiode, in particular an avalanche photodiode, and preferably a so-called SPAD (for single-photon avalanche diode). Avalanche photodiodes are highly sensitive, fast photodiodes that utilize the internal photoelectric effect for charge carrier generation and the avalanche breakdown for internal amplification. SPADs with temporal resolutions of, for example, 100 ps and better, corresponding to an optical transit time of 3 cm, are already known in the art. The aforementioned IR laser diode, especially the VCSEL, can be integrated on a common semiconductor substrate together with a SPAD and other semiconductor components such as time-to-digital converters (TDCs). TDCs are electronic circuits capable of measuring short to ultrashort time intervals and outputting them digitally, for example, as a data stream. They thus fall under the category of frequency counters.Instead of a single SPAD, an array of SPADs can also be integrated on the common semiconductor substrate.

[0022] When using four time-of-flight sensors evenly distributed around the axis of symmetry, it is advantageous to adapt the sensor-based system to the detection of a smoke detector by the lateral approach of a board in 90° steps in accordance with the aforementioned DIN SPEC 91388.

[0023] The fire detectors suitable for the monitoring device according to the invention have, in particular, a detector dimension parallel to their mounting surface in the range of 6 to 14 cm, preferably 8 to 13 cm. In the case of a typical rotationally symmetrical fire detector, this detector dimension is the detector diameter. The detector height of a fire detector, i.e., the overall height of a fire detector, is in particular in the range of 3 to 7 cm, typically 4 to 6 cm, measured from the mounting surface, i.e., the ceiling, and in the state of the fire detector being installed in or on a detector base. Preferably, the distance between the at least four time-of-flight sensors on the radial outer side of the fire detector, measured from the furthest point towards the mounting surface in the normal direction to the mounting surface, is in the range of 0.5 cm to 3 cm.This “lowest” point, in the case of a fire detector with a commonly occurring, dome-shaped detector cover, is the so-called detector apex of the fire detector.

[0024] The time-of-flight sensors each have an optical detection cone directed radially away from the axis of symmetry, with an associated optical axis. The respective detection cone encompasses a detection angle β in a range of 15° to 40°, particularly from 20° to 35°, preferably in a range of 25° to 30°. The marginal rays bounding the detection cone are dimensioned to a received signal level corresponding to 1 / e 2 This corresponds to a multiple of the maximum received level. The optical axes are inclined towards the axis of symmetry by an angle α measured relative to the mounting surface. The permissible range of the inclination angle α is defined as follows: Inclination angle α<65°−½⋅βα>55°−½⋅β;

[0025] For α to be true, both conditions must be met.

[0026] The relative dimensioning of the detection angles and inclination angles according to the invention ensures that a board (100 cm x 100 cm) aligned with the fire detector, as described at the beginning of DIN SPEC 91388, is reliably and in accordance with standards detected for all possible dimensions of a fire detector in all approach cases.

[0027] The selected tilt angle α should be as small as possible within the 10° range. In other words, the time-of-flight sensors should be tilted more to the side, away from the axis of symmetry, since obstacles or objects located laterally can obstruct the airflow during smoke detection. This is because smoke usually enters from the side. Therefore, the smoke inlet openings are typically located radially on the outside of a fire detector's housing.

[0028] The electronic control unit is connected to at least four time-of-flight sensors. It is configured and programmed to receive distance information from each sensor and issue a warning message if at least one of the received distance readings falls below a predefined, assignable distance value around the fire detector. The electronic control unit is processor-controlled, preferably a microcontroller, and programmed accordingly to perform the fire detector's function.

[0029] According to one embodiment, the monitoring device has exactly four time-of-flight sensors evenly distributed on the radial outer surface of the housing. One of the time-of-flight sensors is positioned at a circumferential orientation that is least sensitive to smoke detection. This also fulfills a test requirement in the aforementioned DIN SPEC 91388, which in turn refers to the standard E DIN EN 14604:2015,5.3.

[0030] According to one embodiment, the specified distance value is in the range of 40 cm to 70 cm, in particular from 50 cm to 60 cm. The distance value is measured from the intersection of the fire detector's axis of symmetry, or its equivalent geometric principal axis, with the mounting surface, i.e., the ceiling.

[0031] According to another embodiment, the respective time-of-flight sensor has an IR emitter and an IR receiver. Both are integrated into a common optoelectronic semiconductor device.

[0032] In particular, the respective IR emitter is a surface emitter laser diode, i.e. a so-called VCSEL (for Vertical Cavity Surface-Emitting Laser Diode) and the respective receiver is a single-photon avalanche diode, i.e. a SPAD (for Single-Photon Avalanche-Diode).

[0033] Preferably, each time-of-flight sensor includes a microcontroller and a digital interface. The microcontroller is configured to repeatedly drive the surface-emitting laser diode to emit light, evaluate a received signal from the single-photon avalanche diode, and generate a distance-dependent intensity distribution. The digital interface is configured to output the generated intensity distribution and / or one or more distance values ​​derived from it to the time-of-flight sensor. The digital interface is typically integrated into the microcontroller.

[0034] According to one embodiment, the electronic control unit is configured, in a commissioning mode of the monitoring device, to generate and store an initial distance profile dependent on the circumferential angle to the axis of symmetry from the respective distance information of the at least four time-of-flight sensors. The electronic control unit is also configured or programmed, in a monitoring mode of the monitoring device, to repeatedly generate an updated distance profile and issue a warning message if the current distance profile deviates significantly from the initial distance profile.

[0035] Alternatively or additionally, the electronic control unit can be configured or programmed to output the initial distance profile and / or the updated distance profile to a data interface of the fire detector if the current distance profile deviates significantly from the initial distance profile. A significant deviation is defined as a value of no more than 10%, and in particular no more than 5%. The data interface can be a wired interface, for example, for connection to a detector bus. Alternatively, it can be a wireless data interface and be based, for example, on a WLAN, Bluetooth, or mobile communication standard (GSM, 4G, 5G). The two distance profiles can then be viewed by a user on a remote display device, such as a smartphone, tablet, or PC.

[0036] The particular advantage is that structural measures carried out in the vicinity of the fire detector after its commissioning can be automatically detected by the monitoring device or automatically by the environmental monitoring system and assessed to determine whether these structural measures are still permissible with regard to the aforementioned standard and DIN SPEC 91388.

[0037] In one embodiment, the IR emitter is a surface-emitting laser diode. The receiver is a two-dimensional single-photon avalanche diode array with N rows and columns of single-photon avalanche diodes. The time-of-flight sensor includes a microcontroller and a digital interface. The microcontroller is configured to repeatedly drive the surface-emitting laser diode to emit light and to evaluate one or more received signals, which originate from a single-photon avalanche diode or group of single-photon avalanche diodes configurable by the control unit. The microcontroller is also configured to generate a corresponding number of distance-dependent intensity distributions.The respective digital interface is set up to output the respective distance-dependent intensity distributions and / or the respective distance information derived from them to the time-of-flight sensor.

[0038] In comparison to the previous embodiment, the configuration via the control unit allows for the selective and advantageous exclusion of one or more groups of single-photon avalanche diodes, each with a partial detection cone. This is the case, for example, when a fire detector must be mounted at an otherwise impermissible distance from a permissible beam.

[0039] According to one embodiment, the respective single-photon avalanche diode or the respective group of single-photon avalanche diodes can be assigned to a partial detection cone dependent on the circumferential angle and the inclination angle with respect to the axis of symmetry.

[0040] According to a further embodiment, the electronic control unit is configured or programmed to generate and store an initial spatial distance profile, dependent on the circumferential angle and the tilt angle relative to the axis of symmetry, from the respective distance-dependent intensity distributions of the at least four time-of-flight sensors in a commissioning mode of the monitoring device. The electronic control unit is also configured or programmed to repeatedly generate an updated spatial distance profile in a monitoring mode of the monitoring device and to issue a warning message if the current spatial distance profile deviates significantly from the initial spatial distance profile.

[0041] Alternatively or additionally, the electronic control unit can be configured or programmed to output the initial room distance profile and / or the updated room distance profile to a data interface of the fire detector if the current room distance profile deviates significantly from the initial room distance profile. The data interface can be configured as in the previous embodiment. The two room distance profiles can then be viewed by a user on a remote display device, as described previously. For both previous embodiments, a significant deviation is defined as a value of no more than 10%, and in particular, no more than 5%.

[0042] The advantage here is also that structural measures carried out in the vicinity of the fire alarm after its commissioning can be identified and assessed to determine whether these structural measures are permissible with regard to the aforementioned standard and DIN SPEC 91388.

[0043] The object of the present invention is further achieved by a fire detector with a monitoring device according to the invention. The fire detector is, in particular, a smoke detector. The fire detector comprises a housing and a mounting surface formed thereon for at least indirect attachment of the fire detector to an opposite flat mounting surface, in particular to a ceiling. According to the invention, the fire detector has such a monitoring device for detecting objects in the vicinity of the fire detector. The at least four time-of-flight sensors of the monitoring device are arranged in or on a radial outer surface of the housing with respect to an axis of symmetry of the fire detector, preferably distributed uniformly in the circumferential direction with respect to the axis of symmetry. The fire detector has an electronic control unit which is configured for this purpose.It is programmed to issue a fire alarm in the event of a detected fire and a warning message in the event of a detected object.

[0044] According to one embodiment of the fire detector, it has an optical measuring chamber (labyrinth) for smoke detection integrated into the housing. The optical measuring chamber is preferably shielded from direct ambient light, but is permeable to smoke to be detected via at least one smoke inlet opening in the housing.

[0045] Alternatively, the fire detector according to the invention can be designed as an open scattered light smoke detector. It then has a scattered light center or scattered light volume located outside the housing of the fire detector.

[0046] Finally, the object of the present invention is achieved by an additional device for a fire detector designed as a point detector. The additional device is a separate component that can be attached to the fire detector. The additional device has a centrally arranged base for receiving the fire detector. Alternatively, it is designed to laterally surround the fire detector. Furthermore, according to the invention, the additional device comprises such a monitoring device. The at least four time-of-flight sensors of the monitoring device are arranged in a lateral exterior area of ​​the additional device, located radially away from the attached fire detector, for the detection of objects in the vicinity of the fire detector.

[0047] The advantage of the additional device is that a "conventional" fire alarm or smoke detector can subsequently be extended to include the function of monitoring for unauthorized objects in the vicinity of the fire alarm or smoke detector.

[0048] The invention and advantageous embodiments of the present invention are evident from the following figures. Fig. 1 a sectional view through an exemplary fire detector and through an exemplary accessory device for a fire detector, each with a monitoring device according to the invention in a common view, Fig. 2. A top view of the fire alarm or the additional equipment with the fire alarm in accordance with the Fig. 1 registered direction of view II, Fig. 3. A test procedure applied to an exemplary fire alarm in accordance with the standard DIN 14676 in conjunction with the associated DIN SPEC 91388 for functional testing on objects in the vicinity of the fire alarm using test plates. Fig. Four views of an exemplary time-of-flight sensor with a VCSEL and a SPAD, and Fig. 5 a top view of an exemplary two-dimensional array of single-photon avalanche diodes of another time-of-flight sensor and the resulting partial detection cone.

[0049] Fig. Figure 1 shows a cross-sectional view through an exemplary fire detector 10 and through an exemplary accessory device ZE for a fire detector 10, each with a monitoring device 1 according to the invention in a common representation.

[0050] In the case of the fire detector 10, it is attached to a detector base 20, which in turn is attached to a mounting surface D, typically a ceiling. The fire detector 10 shown has a detector height designated MH when mounted. MD denotes the diameter of the fire detector 10. Furthermore, the fire detector 10 has a housing 2, which consists of a base body 21 and a detector cover 22. Inside the housing 2 is an optical measuring chamber M for smoke detection, which communicates with the ambient air via several smoke inlet openings OF. The housing 2 also contains a circuit carrier 5, on which an electronic control unit 6 is arranged. In the event of a detected fire, the control unit 6 can issue an alarm message AL, e.g., to a connected detector bus.

[0051] The fire detector 10 according to the invention comprises a monitoring device 1 which, with respect to an axis of symmetry of the fire detector 10 designated A, has, by way of example, four time-of-flight sensors 3 arranged on a radial outer surface RA of the housing 2 of the fire detector 10. The latter are each designed as a single unit, i.e., as an individual optoelectronic component. In the present example, the time-of-flight sensors 3 are arranged uniformly in the circumferential direction with respect to the axis of symmetry A, i.e., in a 90° angular grid (see below). Fig. 2) A further time-of-flight sensor 4 is arranged on the detector hood 22 as part of the monitoring device 1. This is not absolutely necessary for the environmental monitoring according to the invention and the aforementioned standard, but can support the task of environmental monitoring by specifically looking "downwards".

[0052] The four time-of-flight sensors 3 each have an optical detection cone FOV directed radially away from the axis of symmetry A, with an associated optical axis OA. The respective detection cone FOV encompasses a detection angle β in a range of 15° to 40°, particularly from 20° to 35° and preferably from 25° to 30°. The optical axes OA are inclined at an angle α relative to the mounting surface BF and are oriented towards the axis of symmetry A.

[0053] The following relationship applies to the angle of inclination α: α<65°−½⋅β and also α>55°−½⋅β;

[0054] The preferred angle values ​​in the range of 25° to 30° for the field of view (FOV) are typical for commercially available, inexpensive time-of-flight sensors 3. These are used in large quantities, for example, in smartphones, drones, or robotic vacuum cleaners. The tilt angle α is dimensioned, depending on the detection angle β, such that reliable detection of the horizontal and vertical test plates (100 cm x 100 cm) prescribed in the aforementioned DIN SPEC 91388 for testing a fire detector is possible. This is also true assuming a minimum distance of the time-of-flight sensors 3 from the mounting surface and assuming a maximum detector diameter MD of 14 cm for the rotationally symmetrical fire detector 10 used here as an example (see also...). Fig. 3) If the time-of-flight sensors 3 have an angle value of at least 35° to 40° for the detection cone FOV, then the detection of a so-called beam UZ extending from the ceiling D is also possible. The latter are predominantly wooden beams of the ceiling structure. Such beams are specifically regulated in the aforementioned DIN 14676-1:2018-12 and the associated DIN SPEC 91388 with regard to the testing of a fire detector.

[0055] According to the invention, the electronic control unit 6 is connected to the four time-of-flight sensors 3 via signals and / or data and is configured to receive distance information from the four time-of-flight sensors 3 and to output the warning message W if at least one of the received distance measurements falls below a predefined distance value around the fire detector. The dimensions of the fire detector 10, i.e., the detector diameter MD and the detector height MH, can be taken into account by the control unit 6 for the assignment of the distance information to the distance value (see also Fig. 3, reference DIST).

[0056] In the same Fig. Figure 2 also shows an accessory device ZE for a fire detector 10 designed as a point detector. This is a separate component that can be attached to the fire detector 10. The accessory device ZE shown comprises a centrally arranged base for receiving the fire detector 10. Furthermore, according to the invention, the accessory device ZE has a monitoring device 1 analogous to the previously described fire detector 10. In the present example, the four time-of-flight sensors 3 of the monitoring device 1 are arranged in a lateral external area AR of the accessory device ZE, located radially away from the attached fire detector 10, for the detection of objects in the vicinity of the fire detector 10. The lateral external area AR of this accessory device ZE thus protrudes slightly beyond the detector diameter MD, specifically in a range of 0.5 cm to 5 cm.The overhang corresponds to half the difference between the diameter ZD of the auxiliary device ZE and the detector diameter MD. The arrangement and orientation of the four time-of-flight sensors 3 are analogous to those of the fire detector 10 according to the invention. In this case, the control unit of the auxiliary device ZE is housed within the housing of the auxiliary device ZE and functions identically to the control unit 6 of the fire detector 10 according to the invention. The overhang allows for optical monitoring of the surroundings beyond the "conventional" fire detector housed in the auxiliary device ZE.

[0057] Fig. Figure 2 shows a top view of the fire detector 10 or of the additional device ZE with the fire detector 10 according to the in Fig. 1. Viewing direction II. In this representation, the even distribution of the four Time-of-Flight sensors 3 around the axis of symmetry A is particularly easy to see.

[0058] Fig. Figure 3 shows a test procedure applied to an exemplary fire detector 10 in accordance with the standard DIN 14676 in conjunction with the associated DIN SPEC 91388 for functional testing on objects in the vicinity of the fire detector 10 using test plates H50, H55, V50.

[0059] In the left and right parts of the Fig. 3. Two test plates V50, aligned with the mounting plane D, are arranged at a horizontal distance HA50 of 50 cm from the fire detector 10 for testing purposes. The horizontal distance HA50 can vary by ± 5 cm for the test. In the left part, a support beam UZ with a maximum permissible height h of 20 cm, as specified in the aforementioned standard and DIN SPEC, is also arranged at the same position. Up to this height, such support beams UZ can be disregarded for the test. In the lower part of the Fig. Test plate 3, a horizontally oriented test plate H50, is positioned at a distance VA50 of 50 cm from the fire detector 10 for testing purposes. The vertical distance VA50 can vary by ± 5 cm for testing, as shown by the dashed line indicating the position of test plate H55. All test plates H50, H55, and V50 have dimensions of 100 cm x 100 cm.

[0060] In the left part of the Fig. Figure 3 shows an exemplary time-of-flight sensor 3 arranged at an inclination angle α of 40° with a detection angle β of 33°. According to the invention, the inclination angle α satisfies the relationship: α < 65° - ½ · β ∧ α > 55° - ½ · β. That is, the angle value of 40° lies between the calculated lower and upper angle values ​​of 38.5° and 48.5°. In the right part of the Fig. In section 3, the time-of-flight sensor has a narrower detection angle β of 25°. The angle value for α there, 45°, also lies between the calculated lower and upper angle values ​​of 42.5° and 52.5°, respectively.

[0061] Finally, DIST denotes a distance value measured from the intersection of the axis of symmetry A with the mounting surface D. If an object is detected in the monitoring mode of the fire detector 10 with a distance value DIST of less than 50 cm, then a warning message W is issued by the control unit 6 of the fire detector 10.

[0062] Fig. Figure 4 shows a top and side view of an exemplary typical time-of-flight sensor 3 with a vertical cavity surface-emitting laser diode (VCSEL) as an example IR emitter 31 and with a single-photon avalanche diode (SPAD) as an example IR receiver 32. Alternatively, the IR receiver 32 can also be a CMOS photosensor. The time-of-flight sensor 3 shown has an integrated microcontroller (MC) and a digital interface. The digital interface can also be integrated into the microcontroller (MC). The microcontroller (MC) is configured to repeatedly drive the VCSEL to emit light, evaluate a received signal from the SPAD, and generate a distance-dependent intensity distribution (HIST).The generated intensity distribution HIST and / or a distance information AB derived from it can be output via the digital interface to the Time-of-Flight Sensor 3.

[0063] In the right part of the Fig. Figure 4 shows how the emitted light cone of the surface-emitter laser diode VCSEL, 31, and the optical receiving cone of the single-photon avalanche diode SPAD, 32, merge into a common detection cone FOV with a detection angle β in the far field FF, i.e., after a few millimeters. OA denotes the common optical axis. 30 denotes solder contacts of the time-of-flight sensor 3 for SMD mounting.

[0064] Fig. Figure 5 shows a top view of an exemplary two-dimensional array (ARRAY) of single-photon avalanche diodes (SPAD) of another time-of-flight sensor (3) and the resulting partial optical detection cones (FOV1–FOV4), again in the far field (FF). In the left part of the Fig. 5 are groups of SPADs shown hatched, which are interconnected within a configuration by the microcontroller MC of the further time-of-flight sensor 3 for a group-wise distance-dependent intensity distribution HIST. Reference symbol list 1 monitoring device 2 housings, detector housings 3 ToF sensor, time-of-flight sensor 4 additional ToF sensors 5 circuit carriers, printed circuit board 6 electronic control unit, microcontroller 10 fire alarms, smoke detectors 20 detector bases 21 Basic shapes 22 Detector hood 30 solder connection side, solder contacts 31 Emitters, IR emitters 32 receivers, IR receivers A axis of symmetry, axis of rotational symmetry AB Distance Information AL alarm message, alarm signal AR radial exterior AT distance of the time-of-flight sensor ARRAY Single-photon avalanche diode array BF mounting surface CMOS CMOS receiver Mounting surface, ceiling DIST distance value FF Fernfeld FOV field of view FOV1-FOV4 partial detection cone GROUP group of single-photon avalanche diodes h height of a beam H50 horizontally oriented plate H55 another horizontally oriented plate HA50 horizontal distance value HIST distance-dependent intensity distribution M optical measuring chamber MC microcontroller MH detector height MD diameter of the fire detector OA optical axis, principal optical axis OF smoke entry openings RA radial outer surface, radial outside SPAD single-photon avalanche diode UZ underbody V50 vertically arranged test plate VA50 vertical distance value VCSEL surface emitter laser diode W Warning message, warning information ZE Additional Equipment ZD Diameter of the auxiliary device, diameter of the detector base α Angle of inclination β Detection angle δ circumferential angle

Claims

[1] Monitoring device, in particular environmental monitoring, for a fire detector (10) for detecting objects in the vicinity of the fire detector (10), wherein the monitoring device (1) has a housing (2) with a mounting surface (BF) for at least indirect attachment to an opposite flat mounting surface (D), in particular to a ceiling, and wherein the monitoring device (1) has an electronic control unit (6) configured to output a warning message (W) and / or at least distance information (AB) in the event of a detected object, characterized by , - that the monitoring device (1) has at least four time-of-flight sensors (3) arranged as a unit on a radial outer surface (RA) of the housing (2) with respect to an axis of symmetry (A) of the fire detector (10), which are preferably arranged uniformly in the circumferential direction (δ) to the axis of symmetry (A), - that the time-of-flight sensors (3) each have an optical detection cone (FOV) directed radially away from the axis of symmetry (A) with an associated optical axis (OA), wherein the respective detection cone (FOV) comprises a detection angle (β) in a range of 15° to 40°, in particular 20° to 35°, preferably 25° to 30°, wherein the optical axes (OA) are inclined to the axis of symmetry (A) by an inclination angle (α) dimensioned towards the mounting surface (BF), and wherein the following applies to the inclination angle α: α < 65° - ½ · β ∧ α > 55° - ½ · β ; - that the electronic control unit (6) is connected to the at least four time-of-flight sensors (3) via data transmission and is configured to receive distance information (AB, HIST) from the respective time-of-flight sensors (3) and to issue the warning message (W) if at least one of the received distance information (AB, HIST) falls below an assignable predefined distance value (DIST) around the fire detector (10). [2] Monitoring device according to claim 1, wherein the monitoring device has exactly four time-of-flight sensors (3) arranged evenly distributed on the radial outside (RA) of the housing (2) and wherein one of the time-of-flight sensors (3) is arranged at a circumferential direction position that is least sensitive for smoke detection. [3] Monitoring device according to claim 1 or 2, wherein the specified distance value (DIST) is in the range of 40 cm to 70 cm, in particular 50 cm to 60 cm. [4] Monitoring device according to one of the preceding claims, wherein the respective time-of-flight sensor (3) comprises an IR emitter (31) and an IR receiver (32) integrated into a common optoelectronic semiconductor device. [5] Monitoring device according to claim 4, wherein the respective IR emitter (31) is a surface emitter laser diode (VCSEL) and the respective receiver (32) is a single photon avalanche diode (SPAD). [6] Monitoring device according to claim 5, wherein the respective time-of-flight sensor (3) comprises a microcontroller (MC) and a digital interface, wherein the respective microcontroller (MC) is configured to repeatedly drive the surface emitter laser diode (VCSEL) to emit light, to evaluate a received signal from the single-photon avalanche diode (SPAD) and to generate a distance-dependent intensity distribution (HIST), and wherein the respective digital interface is configured to output the generated intensity distribution (HIST) and / or a distance information (AB) derived therefrom to the time-of-flight sensor (3). [7] Monitoring device according to claim 6, wherein the electronic control unit (6) is configured to - in a commissioning mode of the monitoring device (1) to generate and store an initial distance profile dependent on a circumferential angle (δ) to the axis of symmetry (A) from the respective distance information (AB) of the at least four time-of-flight sensors (3), and - in a monitoring mode of the monitoring device (1) to repeatedly generate an updated distance profile and issue the warning message (W), and to output the initial distance profile and / or the updated distance profile to a data interface of the fire detector if the current distance profile differs significantly from the initial distance profile. [8] Monitoring device according to claim 4, wherein the respective IR emitter (31) is a surface emitter laser diode (VCSEL), wherein the respective receiver (32) is a two-dimensional single-photon avalanche diode array (ARRAY) with a number N of rows ZL and columns SP of single-photon avalanche diodes (SPAD), wherein the respective time-of-flight sensor (3) comprises a microcontroller (MC) and a digital interface, wherein the respective microcontroller (MC) is configured to repeatedly drive the surface emitter laser diode (VCSEL) to emit light, to evaluate one or more received signals, which is or are specified by a single-photon avalanche diode (SPAD) configurable by means of the control unit (6).originates from a group (GROUP) of single-photon avalanche diodes (SPAD) configurable by means of the control unit (6), and is set up to generate a corresponding number of distance-dependent intensity distributions (HIST), wherein the respective interface is set up to output the respective distance-dependent intensity distributions (HIST) and / or the respective distance information (AB) derived therefrom to the time-of-flight sensor (3). [9] Monitoring device according to claim 8, wherein the respective specified single-photon avalanche diode (SPAD) or the respective specified group (GROUP) of single-photon avalanche diodes (SPAD) can be assigned to a partial detection cone (FOV1-FOG4) which depends on a circumferential angle (δ) and on the inclination angle (α) with respect to the axis of symmetry (A). [10] Monitoring device according to claim 8 or 9, wherein the electronic control unit (6) is configured to - in a commissioning mode of the monitoring device (1) to generate and store an initial spatial distance profile from the respective distance-dependent intensity distributions (HIST) of the at least four time-of-flight sensors (3) which is dependent on a circumferential angle (δ) and on the tilt angle (α) with respect to the axis of symmetry (A), and - in a monitoring mode of the monitoring device (1) to repeatedly generate an updated room distance profile and issue the warning message (W), and to output the initial room distance profile and / or the updated room distance profile to a data interface of the fire detector if the current room distance profile differs significantly from the initial room distance profile. [11] Fire detector, in particular smoke detector, with a housing (2) and with a mounting surface (BF) formed thereon for at least indirectly attaching the fire detector (10) to an opposite flat mounting surface (D), in particular to a ceiling, wherein the fire detector (10) has a monitoring device (1) according to one of the preceding claims 1 to 10 for detecting objects in the vicinity of the fire detector (10), wherein, with respect to an axis of symmetry (A) of the fire detector (10), the at least four time-of-flight sensors (3) of the monitoring device (1) are arranged in or on a radial outer surface (RA) of the housing (2), preferably distributed uniformly in the circumferential direction to the axis of symmetry (A), and wherein the fire detector (10) has an electronic control unit (6) configured to issue a fire alarm (AL) in the event of a detected fire and a warning message (W) in the event of a detected object. [12] Fire detector according to claim 11, comprising an optical measuring chamber (M) for smoke detection housed in the housing (2), wherein the optical measuring chamber (M) is shielded from direct ambient light, but is permeable to smoke to be detected via at least one smoke inlet opening (OF) in the housing (2). [13] Additional device for a fire detector (10) designed as a point detector, wherein the additional device (DE) is a separate assembly unit that can be attached to the fire detector (10), wherein the additional device (DE) has a centrally arranged base for receiving the fire detector (10) or is designed for lateral framing of the fire detector (10), wherein the additional device (DE) has a monitoring device (1) according to one of claims 1 to 10, and wherein the at least four time-of-flight sensors (3) of the monitoring device (1) are arranged in a lateral outer area (AR) of the additional device (DE) located radially away from the attached fire detector (10) for detecting objects in the vicinity of the fire detector (10).

Images