EP3270362B1 - Fire alarm with a measurement chamber and a switch holder for joint assembly of a fire sensor of the measuring chamber and at least one further sensor for detecting a measured variable in the environment outside the fire detector - Google Patents

Description

The invention relates to a fire detector which has a circuit carrier and a measuring chamber communicating with the ambient air. The measuring chamber comprises a fire sensor for detecting a fire characteristic. It is also housed in a detector housing of the fire detector. The measuring chamber comprises a base body as well as an opposing attachment body with a measuring space formed therebetween. The main body is designed for attachment to a mounting surface, in particular on a detector base.

The measuring chamber can also be referred to as a detection unit. The base body and the Aufsetzkörper are typically assembled during assembly.

From the EP 0 588 232 A1 an optical smoke detector is known in which at least one planar-optical element is arranged in the beam path between the radiation source and the radiation receiver. This element can be either a diffractive element, preferably a holographic-optical element (HOE), or a microfine reflector (MFR).

From the not yet published European patent application of the applicant with the registration file 16189021.5 a smoke detector and a method for monitoring a smoke detector are known. The smoke detector comprises a sensor system for detecting an adjacent object, ultrasound signals can be transmitted and received by means of the sensor system, and a received ultrasound signal can be evaluated to detect an object. The sensor system comprises a plurality of ultrasound transmitters, which are aligned in such a way that they are in operation in the direction of a mounting surface, on which the smoke detector is mounted, radiate. According to a local embodiment according to the local FIG. 10, the monitoring circuit of the smoke detector has as a receiver a microphone in the ultrasonic range, which is oriented in a direction away from the mounting surface, typically towards the ground. The microphone may be, for example, an electret microphone or a microphone in silicon technology (semiconductor technology), which is substantially smaller than a piezoelectric transducer. The microphone can be so small that it can be placed unobtrusively under the hood of the smoke detector.

From the not yet published European patent application of the applicant with the registration file 15180045.5 a scattered light smoke detector is known, which has a communicating with the ambient air optical measuring chamber. The latter is accommodated inside a detector housing and limited by a main body and a detector hood of the detector housing. In the main body, a preferably planar circuit carrier is added. On this, a light emitting diode and a photosensor are arranged in a scattered light arrangement adjacent to the measuring chamber. The light-emitting diode and the photosensor each have an optical axis extending at least approximately orthogonally to the circuit carrier and lie opposite an inner side of the detector hood which delimits the measuring chamber. A part of the inside has a mirror surface, which is opposite to the light emitting diode. The mirror surface has a mirror geometry such that a light cone of the light-emitting diode intersects a reception region of the photosensor in a first scattered light volume within the measurement chamber.

Fire detectors are well known. Like the fire detector according to the invention, they can be designed for connection to a detector bus or to a detector line. If a fire characteristic is detected, an alarm or warning message is output to the detector bus. Both messages can alternatively or additionally via radio and / or on Fire alarms are issued visually and / or acoustically. The considered fire detectors designed as point detectors can alternatively or additionally be designed for battery-supported stand-alone operation. The documents EP0399 244 and FR2 964 743 show scattered light smoke detector, which have a circuit carrier, the front side of the scattered light chamber faces and on the back of which electronic components are arranged.
On this basis, it is an object of the invention to provide a particularly compact fire detector.
Another object of the invention is to provide a fire detector in which the cost of EMC shielding the fire alarm is reduced.
The object is achieved with the objects of the main claim. Advantageous embodiments of the present invention are indicated in the dependent claims.
According to the invention, the circuit carrier bears against the mounting body with an inner side facing the measuring space. On one of the inside of the circuit substrate opposite outside at least one other sensor is arranged in each case for detecting a measured variable in the environment and thus outside the fire detector and / or an indicator LED for optical output of a fire alarm in the environment of the fire detector. The circuit carrier is provided for arranging the fire sensor and the at least one further sensor and / or the indicator LED.
The core of the invention lies in the double use of the circuit carrier with the sensors applied there. Here is the part of the sensors, ie the fire sensor, part of the adjacent measuring chamber and sensor aligned to the measuring chamber. By contrast, the other part of the sensors, ie the at least one further sensor, is directed away from the measuring chamber into the adjacent surroundings of the fire detector.
As a result, advantageously no separate line for the electrical connection of the sensors to the circuit carrier is required. Such a line must often be manually soldered to the circuit board.

Another advantage is that the direct mounting of the sensors on the circuit carrier drastically reduces the EMC influence on the sensors. This is the case in particular for sensors which are designed as SMD components for direct surface mounting on the circuit carrier. Here elaborate shielding measures can be omitted.

Another advantage is that no more optical fiber is needed for the optical discharge of the light emitted by the indicator LED light in the environment of the fire detector. The indicator LED is provided to cyclically output a light pulse to indicate proper operational readiness and / or to indicate the presence of a fire alarm, such as a fire alarm. by faster flashing.

Finally, the inventive fire detector with significantly reduced manufacturing and assembly costs can be produced.

The measuring chamber communicating with the ambient air may be an optical measuring chamber, such as a so-called labyrinth. Such a measuring chamber is permeable to the passage of smoke particles to be detected and to be detected combustion gases, such as carbon monoxide. On the other hand, the measuring chamber is shielded from direct ambient light. The optical measuring chamber can be based on the scattered light principle or on the extinction principle. In this case, the fire sensor has a light-emitting diode and a photosensor as part of the optical measuring chamber. Alternatively or additionally, the measuring chamber may have one or more gas sensors as a fire sensor for detecting flammable flue gases typical of fire. Such a fire detector is also referred to as a flue gas detector. In this case, the gas sensor, such as a so-called GasFET, protrudes into the measuring chamber of the measuring chamber.

The fire sensor is the main sensor of the fire detector.

According to one embodiment, the detector housing comprises a base housing and a detector hood with at least one inlet opening formed therebetween. The latter is intended for the passage of combustion gases and smoke particles into the measuring chamber of the fire detector. The entrance opening may be slit-shaped, e.g. with a slit width in the range of 2 to 5 mm. There may be a plurality of circular inlet openings with a diameter in the range of 2 to 10 mm in the detector housing. The detector hood has a hood outer side facing away from the fire detector, and an opposite hood inside. The circuit board is located on the hood inside. Alternatively, the circuit carrier with a maximum distance A of 1.5 cm from the hood inner side spaced.

In addition, the at least one further sensor and / or the indicator LED is opposite an opening in the detector hood or protrudes into this opening or protrudes through this opening.

Preferably, the (central) opening is located at a central position of the fire detector, in particular at a vertex of the detector hood. The opening may be a recess. It preferably has a circular diameter. The diameter is in particular in a range of 1 to 30 mm, preferably in a range of 3 to 15 mm.

The main body and the detector hood can both be in one piece. They are both preferably plastic injection molding parts. The circuit carrier accommodated in the detector hood is preferably a planar printed circuit board.

According to one embodiment of the invention, the fire detector has a control unit arranged on the control unit, preferably a microcontroller. The control unit is each signal or data technology with the fire sensor for detecting a fire characteristic and with the at least one sensor for detecting the respective measured variable and / or connected to the indicator LED for optical output of the operating display. The control unit has an interface and is adapted to detect by the interface a respective sensor information and / or output by the interface a respective alarm message in an impermissible deviation from a respective detected sensor measured value.

The control unit may be configured to bundle the respective alarm messages and output them as an alarm message. It can also be set up to evaluate and / or weight the respective alarm messages in the sense of a multi-criteria alarm in combination. It can finally be set up to use the further sensor signals for testing the fire sensor signal for plausibility. This reduces the output of a false alarm.

According to one embodiment, the at least one sensor is a temperature sensor and in particular a thermistor for detecting a temperature in the immediate vicinity of the fire detector. Preferably, the thermistor is a so-called NTC (for negative temperature coefficient thermistor). The control unit is set up, when a temperature value detected by the temperature sensor, such as a temperature value is exceeded. of 60 °, and / or when exceeding a temperature gradient, e.g. of 5 ° / min, to output a temperature information or alarm message.

The at least one further sensor may be a light receiver, such as a photodiode. The light receiver is provided for detecting an ambient brightness. The control unit is set up to suppress the output of an optical and / or acoustic warning message at night when a brightness value, for example 10 lux detected by the photosensor, drops below the output of an optical and / or acoustic warning message, if a battery is to supply energy of the fire detector falls below a voltage value for a low state of charge.

Furthermore, the at least one further sensor may be a gas sensor for detecting a flue gas concentration, in particular carbon monoxide. The gas sensor is e.g. a semiconductor gas sensor, and preferably a so-called gas FET. The control unit is adapted to operate when a minimum gas concentration such as e.g. of 300 ppm carbon monoxide, a gas information and / or an alarm message.

The at least one further sensor may be a thermal radiation sensor for detecting open fire or blazing embers in the vicinity of the fire detector, in particular a thermopile (thermopile) or a bolometer. The control unit is adapted to detect a characteristic flicker frequency, e.g. in the range of 8 to 20 Hz in the sensor signal of the heat radiation sensor to output a flame information and / or an alarm message. The thermal radiation sensor may also include a PIR sensor (for Passive InfraRed) for detecting movements such as motion. of people to be in the vicinity of the fire alarm. In this case, the control unit is set up to output movement information or an alarm message upon detected movement of objects.

Finally, the at least one further sensor may be a microphone for receiving ultrasonic waves from the surroundings of the band detector. The control unit is set up to evaluate a microphone signal output by the microphone in terms of time, for example with respect to temporal reference to ultrasonic waves, which are preferably emitted cyclically by the fire detector and which are reflected by objects in the vicinity of the fire detector. By means of the control unit, a fault message can then be output if a detected object is within a predetermined distance from the fire detector. Preferably, the fault message only then is output if the microphone signal exceeds a minimum level, so that smaller microphone levels of typically smaller and negligible objects can be disregarded.

The microphone may alternatively or additionally be provided and designed to receive noises from the environment of the fire detector. The control device may in this case be adapted to output a noise information or an alarm message when a microphone detected noise level exceeds a minimum level.

According to a further embodiment of the invention, the detector hood has a (continuous) opening in a vertex of the detector hood. In this case, the outside of the circuit substrate is opposite to the opening. The vertex is preferably located on an axis of symmetry, in particular on a rotational symmetry axis or constructive main axis of the fire detector. Typically, fire detectors have an approximately rotationally symmetrical design. From this central point, a uniform "all-round view" around the fire detector is advantageously possible. At the same time, an advantageously direction-independent temperature detection by means of the temperature sensor is possible at this central point.

According to a further embodiment of the invention, the opening in the detector hood is provided with a cover which is transparent to electromagnetic radiation in the wavelength range from 400 nm to 25 μm. The transparent cover may be made of a plastic or of glass. It can completely close the opening. Alternatively, the transparent cover may have one or more passage openings to allow passage of ambient air for temperature detection or fire gas detection to the at least one sensor. The transparent cover may also form an optical lens for expanding the optical detection area. This is open fire, blazing embers or movements of larger objects, such as For example, by humans, advantageously detectable in a larger environment of the fire alarm.

According to a further embodiment, at least the heat radiation sensor is arranged on the circuit carrier. The opening in the detector hood is provided with a cover which is transparent only for medium infrared radiation in the wavelength range from 2 to 25 μm.

As a result, the cover appears in the optically visible region of a human being as opaque, in particular as opaque. The transparent cover may for example be made of a plastic, in which scattering particles are introduced. The plastic may alternatively have a structuring which scatters visible light and allows medium infrared radiation to pass to the major part. By "visible light" is meant the human optically perceptible wavelength range of about 380 nm to 780 nm. Suitable materials for the cover are eg from the EP 2 715 792 A1 known.

In a further embodiment of the invention, the fire sensor comprises a light-emitting diode and a photosensor (6). The light emitting diode and the photosensor are arranged in a scattered light arrangement for optical smoke detection according to the scattered light principle. Alternatively or additionally, the light-emitting diode and the photosensor are arranged opposite each other for optical smoke detection according to the extinction principle. Also in this case, the measuring volume for the transmitted light measurement is in the measuring chamber of the measuring chamber.

The light-emitting diode can be a single-color light-emitting diode which emits monochromatic light, for example in the wavelength range from 380 to 1000 nm. It can be a two-color light-emitting diode which is designed to generate a first light beam or a first light cone in a first wavelength range from 380 to 540 nm and / or a second light beam or a second light cone in a second wavelength range from 750 to 1000 nm for smoke detection according to the two-color principle send out. Due to the color-specific evaluation of the photosensor signal, a fire technical analysis of the detected smoke particles with regard to their particle size and thus a determination of the type of smoke is possible.

According to a further embodiment of the invention, the light emitting diode and the photosensor are optically aligned to a common scattered light volume within the measuring space. The photosensor is arranged on the circuit carrier in such a way that a main axis or axis of symmetry extending through the center of the fire detector extends both through the scattered light volume and through the photosensor. As a result, a largely direction-independent smoke detection is advantageously possible.

According to a particularly advantageous embodiment of the invention, the light-emitting diode and the photosensor are arranged and aligned on the circuit carrier such that they each have an optical axis extending at least approximately orthogonally to the circuit carrier. A part of the inside of the main body has a mirror surface, which is opposite to the light emitting diode. The mirror surface has a mirror geometry such that a light cone of the light-emitting diode intersects a receiving region of the photosensor in a scattered light volume within the measuring chamber of the measuring chamber. The mirror surface may e.g. have a spherical geometry, which causes a bundling of the incident light beam. The mirror surface may be part of the surface e.g. a ball, an ellipsoid or a paraboloid.

The mirror surface may have a plane or a concave surface. It may be a silvery foil or a sheet metal piece, such as aluminum or steel. The film can be glued on the inside of the body. The sheet metal piece can be glued to this inside, for example, or attached during injection molding of the body. The mirror surface may also be a metallized surface which For example, by means of a vapor deposition in vacuum is applied. The mirror surface may also be a plastic mirror with a shiny or polished surface, such as black plastic.

The use of the inside of the body as a mirror or as a reflector to direct the light emitted by the light emitting diode orthogonal to the circuit substrate light beam through a central region in the interior of the detector housing, advantageously allows the production of a particularly compact and at the same time structurally simple fire detector.

In the seating body are recesses for the fire sensor, such as e.g. for the light-emitting diode and for the photosensor, available. The attachment body preferably has or forms at least one diaphragm for the light-emitting diode and for the photosensor, the light trap and / or light-absorbing structures as integral parts of the attachment body. The attachment body is preferably a black plastic injection molded part. He can be independently provided with a black paint job. In particular, the mounting body covers substantially all of the measuring space of the measuring chamber facing the inside of the circuit substrate except for the aforementioned recesses. The circuit carrier is thus as in a sandwich between the Aufsetzkörper and the detector hood. This advantageously allows a particularly compact design and easy integration of the other sensors and the indicator LED on the circuit board. The latter is advantageously adjacent directly to the detector hood and thus also to the environment to be monitored outside the fire alarm.

The detector hood may, for example, have a spherical, arched design or the shape of a cylindrical lid with a circular flat bottom. It is usually made of a white plastic.

According to a further embodiment of the invention, a part of the inside of the base body has a focusing element, which is opposite to the photosensor and which has such a focus geometry that scattered light is reflected from the scattered light volume in the direction of the photosensor. In particular, the focusing element is arranged such that the constructive main axis or the rotational axis of symmetry of the fire detector extends through the (geometric) center of the focusing element and through the scattered light volume and is aligned with the optical receiving axis of the photosensor. Due to the additionally incident on the photosensor scattered light, the sensitivity of the photosensor is advantageously increased.

The focusing element has according to a further embodiment of the invention, a plurality of optically reflective and adjacent segments. Each segment is part of an ellipsoid, in particular an ellipsoid of revolution, whose first focal point lies in the scattered light volume and whose second focal point lies directly in front of the photosensor. By "immediate" is meant that the second focus is at a distance of not more than 5 mm in front of the photosensitive sensor layer of the photosensor. The segmented design of the focusing element results in a low overall height of the focusing element. As a result, the focusing element protrudes less into the measuring chamber of the measuring chamber and thus advantageously forms a smaller flow obstacle against penetrating smoke. The focusing element is preferably designed as a "black" mirror. In particular, it is a shiny part of an injection molded part made of black plastic of the main body.

According to a further embodiment of the invention, the mirror surface opposite the light-emitting diode has a mirror geometry such that the light cone of the light-emitting diode traverses the measuring space and opens into a light-absorbing light trap.

By focusing and targeted steering of the light beam is advantageously an effective directional introduction of the light beam in the designated light trap with a nearly complete absorption of light possible.

The light trap is preferably pot-shaped or funnel-shaped. In particular with respect to the main incident direction of the light rays reflected by the mirror surface, it has geometrically oriented surfaces and / or corrugations such that the light rays incident thereon cancel out or "run dead" after a number of reflections.

This advantageously reduces the so-called basic pulse. It thus passes less to the walls and components of the optical measuring chamber reflected light to the photosensor.

According to a particularly advantageous embodiment of the invention, the light trap is shaped in the form of a funnel in the base body. The funnel extends in a radial outer region of the base body substantially coaxially about a main axis extending through the center of the fire detector. The funnel shape advantageously enables even more effective light absorption by a large number of reflections within the funnel. Another advantage lies in the structurally simple spatial integration of the funnel in the radial outer region of the body.

According to a further embodiment of the invention, a plurality of ultrasound transmitters are arranged on the circuit carrier. They are aligned so that they radiate in operation towards a mounting surface on which the fire detector is mounted.

On the circuit carrier, a plurality of ultrasonic receivers or a plurality of ultrasonic transceivers are each arranged as a structural unit of an ultrasonic transmitter and an ultrasonic receiver. The ultrasonic receivers are oriented towards the mounting surface to to detect ultrasonic waves during operation from this direction. Alternatively, at least one microphone as a further sensor of the fire detector is arranged on the circuit carrier such that it lies opposite the opening in the detector hood, protrudes into this opening or protrudes through this opening. The opening is preferably arranged at the apex of the detector hood. The control unit is set up to control the respective ultrasound transmitters for emitting an acoustic signal in the direction of the mounting surface, to evaluate in time a respective ultrasound signal originating from the ultrasound receivers or from the microphone and reflected from objects in the surroundings of the fire detector and to output a fault message if within a predetermined distance around the fire detector, such as at a distance of 50 cm around the fire detector, a detected object is located. Preferably, the fault message can be output if, in addition, the ultrasound signal received by the microphone exceeds a minimum level.

As a result, advantageously larger objects, such as partitions or built-in cabinets, can be detected in the environment around the fire detector, which may possibly be flow-shielding for smoke or combustion gases to be detected.

The mounting surface is typically the ceiling in a building. It can alternatively be a wall. The mounting surface may also be a mounting base on which the fire detector is in particular releasably attachable and which in turn is attached to the ceiling or on the wall. The mounting base is in particular plate-shaped and preferably circular. The mounting base may extend radially outward to the extent that hits an ultrasonic signal or ultrasound beam emitted by the respective ultrasound transmitter or ultrasound transceiver onto the mounting base. This combination of a fire detector according to the invention with such a mounting base has the advantage that regardless of the quality of the ceiling or the wall in relation reflection properties always present on the reflection property for ultrasonic waves.

According to one embodiment, the fire detector has at least one preferably formed in the base body reflection surface in the beam path from the respective ultrasonic transmitter to the mounting surface. The reflection surfaces may be formed such that they have bundling properties for the emitted ultrasonic waves. In particular, the reflection surfaces are concave.

The particular advantage is that the ultrasound transmitter, ultrasound receiver and, as a combination thereof, ultrasound transceivers can be flatly applied to the circuit carrier. The beam steering takes place through the reflection surfaces. In particular, the abovementioned ultrasound units are arranged on the inside of the circuit carrier facing the interior of the fire detector, and preferably on the radial outer edge of the circuit carrier.

FIG 1

eine erste Ausführungsform mit einer Vielzahl weiterer Sensoren sowie mit einer Indikator-LED im Bereich einer zentralen Öffnung in der Melderhaube eines Brandmelders gemäss der Erfindung,

FIG 2

eine Draufsicht auf die Melderhaube mit der zentralen Öffnung entlang der in FIG 1 eingezeichneten Blickrichtung II,

FIG 3

eine zweite Ausführungsform mit einer in einem Zwischenraum zwischen der Melderhaube und einem Aufsetzkörper der Messkammer ausgebildeten Lichtfalle gemäss der Erfindung,

FIG 4

eine dritte Ausführungsform mit einem zentral angeordneten Photosensor und mit einem gegenüberliegendem Fokussierelement gemäss der Erfindung sowie mit einem im radialen Aussenbereich des Grundkörpers ausgeformten Trichter als Lichtfalle gemäss der Erfindung,

FIG 5

eine Draufsicht auf den Brandmelder gemäss FIG 4 entlang der dort eingezeichneten Blickrichtung V,

FIG 6

eine Draufsicht auf den Brandmelder gemäss FIG 4 mit beispielhaft zwei im radialen Aussenbereich des Grundkörpers ausgeformten Trichtern als Lichtfalle,

FIG 7

eine vierte Ausführungsform mit einem Fokussierelement aus drei optisch reflektierenden, aneinander angrenzenden Segmenten gemäss der Erfindung, und

FIG 8

eine fünfte Ausführungsform mit mehreren in Umfangsrichtung verteilt angeordneten Ultraschallsendern und mit einem Mikrophon gemäss der Erfindung.

The invention and advantageous embodiments of the present invention will be explained using the example of the following figures. Showing:

FIG. 1

a first embodiment with a plurality of further sensors and with an indicator LED in the region of a central opening in the detector hood of a fire detector according to the invention,

FIG. 2

a plan view of the detector hood with the central opening along the in FIG. 1 marked line of sight II,

FIG. 3

a second embodiment with a formed in a space between the detector hood and a Aufsetzkörper the measuring chamber light trap according to the invention,

FIG. 4

a third embodiment with a centrally located photosensor and with an opposite focusing element according to the invention and with a formed in the radial outer region of the body funnel as a light trap according to the invention,

FIG. 5

a plan view of the fire detector according to FIG. 4 along the viewing direction V marked there,

FIG. 6

a plan view of the fire detector according to FIG. 4 by way of example two funnels formed in the radial outer region of the main body as a light trap,

FIG. 7

a fourth embodiment with a focusing element of three optically reflective, adjacent segments according to the invention, and

FIG. 8

a fifth embodiment with a plurality of circumferentially distributed ultrasound transmitters and with a microphone according to the invention.

FIG. 1 shows a first embodiment of a fire detector 1 according to the invention with a plurality of other sensors 6 ', 7, 8, TS, MIC and with an indicator LED LED in the region of a central opening OP in a detector hood 4 of the fire detector 1. The fire detector shown. 1 has a measuring chamber M communicating with the ambient air for detecting a fire characteristic by means of a fire sensor 5, 6. A fire characteristic may be, for example, a smoke particle concentration, a fire gas concentration, such as CO concentration, or an excess temperature. The measuring chamber M is in the present example, an optical measuring chamber M, which is also referred to as a labyrinth. It forms a measuring space IR together with a main body G and an attachment body A. The main body G has a connection side AN for attaching the fire detector 1 to a mounting surface, such as on a ceiling or wall on. On the connection side are ON arranged two contacts K, which are connected to the circuit substrate 9 signal or data technology. The contacts K are provided for contacting the fire detector 1 to a detector line. You contact after attachment of the fire detector 1 to a detector base there correspondingly trained mating contacts. The connecting lines between the contacts K and the circuit carrier 9 preferably extend outside the measuring space IR. With MA the outside of the detector hood 4 is designated. The detector hood 4 is a cylindrical cover D in the example shown.

According to the invention, a circuit carrier 9 is arranged in the detector hood 4 with an inner side LI facing the measuring space IR and an outer side LA opposite this. The outside LA of the circuit substrate 9 is located directly on an inner side MI of the detector hood 4. On the circuit carrier 9, a temperature sensor TS are arranged, in particular an NTC, another photosensor 6 'for measuring the ambient brightness, a gas sensor 7, e.g. a GasFET for CO measurement, a heat radiation sensor 8, in particular a thermopile, arranged for flame and motion detection, a microphone MIC and an indicator LED LED for visual operational readiness indication in the environment. The aforementioned components TS, 6 ', 7, 8, MIC, LED are arranged on the circuit carrier 9, that they oppose the opening OP. In the present example, the opening OP has a diameter in the range of 5 to 10 mm and a depth of about 2 mm.

In the present example, the opening OP is arranged in a vertex SP of the detector hood 4, ie centrally or centrally in the detector hood 4. It is thus the outside LA of the circuit substrate 9 of the opening OP directly opposite. By "central" or "central" is meant that the major structural axis or axis of symmetry SA of the fire detector 1 passes through the opening OP.

According to the present example, the opening OP is provided with a cover AB, which is transparent to electromagnetic radiation in the wavelength range from 400 nm to 25 μm. The cover AB is further formed as an optical lens OL for widening the detection area W for heat radiation as well as for light. The optical lens OL shown also forms a radially outer circumferential gap to the outside MA of the detector hood 4 out, so ambient air to determine the ambient temperature and the concentration of combustion gases and sound waves to detect acoustic signals in the opening OP with the other sensors located there TS , 6 ', 7, 8, MIC can arrive.

In the present example, the measuring chamber M is an optical measuring chamber M. The measuring chamber M shown is shielded from direct ambient light by light-shielding elements in the form of lamellae LAM. The shielding elements LAM are preferably an integral part of the main body G or the Aufsetzkörpers A. The optical measuring chamber M is based in the present example on the scattered light principle. The fire sensor 5, 6 is part of the optical measuring chamber M. It comprises a light emitting diode 5 and a photosensor 6 in a scattered light arrangement for optical smoke detection. The photosensor 6 is additionally preceded by a lens 11 for optically focusing the scattered light onto the photosensor 6. The fire detector 1 shown is thus primarily a scattered light smoke detector. Both light-emitting diode 5 and photosensor 6 are arranged on the planar circuit carrier 9 such that their optical axes are orthogonal or nearly orthogonal to the circuit carrier 9 and thus parallel to one another. In the preferred practical case, the light-emitting diode 5 and the photosensor 6 are SMD components which can be applied with high precision and automatically on the circuit carrier 9 with contact areas provided for this purpose.

Furthermore, a part of the inner side GI of the base body G has a mirror surface S, which is opposite to the light-emitting diode 5. The mirror surface S is dimensioned such that the of the Light emitting diode 5 emitted light cone L completely (and only) on the mirror surface S applies. In the present example, the light-emitting diode 5 is a two-color light-emitting diode which is set up to emit a red light beam L and / or a blue light beam L along a substantially identical optical path. The mirror surface S has such a mirror geometry that the light cone L or the light beam intersects a receiving region E of the photosensor 6 in a scattered light volume Z within the optical measuring chamber M. In this case, scattered light passes only from particles in the scattered light volume Z for detection by the photosensor 6. Typically, the receiving area E is a receiving cone.

Further according to the invention, apertures BL, a light trap LF and / or light-absorbing structures AB are provided in the form of corrugations for minimizing the fundamental pulse in the optical measuring chamber M. In the example, the aforementioned constructive elements BL, LF, AB are integral elements of a black glossy or matt Aufsetzkörpers A, which is mounted for covering or attachment to the circuit substrate 9. The Aufsetzkörper A is in the example a one-piece plastic injection molded part. It can also be inseparably composed of several plastic parts. In the body A further two recesses in the form of openings for the light emitting diode 5 and for the photosensor 6 are still present. Preferably, the inside GI of the body G also has light-absorbing structures AB, such as e.g. in the form of corrugations or fluted surfaces. The exception is the mirror surface S, which is e.g. by an attached specular piece of sheet metal or by vapor-deposited metal, e.g. Aluminum, can be realized.

In the example shown, the mirror surface S has such a mirror geometry that the light cone L or the light bundles of the light-emitting diode 5, after being mirrored, actually passes without contact through the measuring space IR of the measuring chamber M and opens into the light-absorbing light trap LF. That there incident, not scattered smoke particles light is effectively absorbed there.

The fire detector 1 shown has for controlling and evaluating the optoelectronic components 5, 6, that is, the light-emitting diode 5 and the photosensor 6, and for outputting an alarm message to an electronic control unit 10. This is preferably a microcontroller and applied to the circuit substrate 9. The control unit 10 is set up or programmed to actuate the light-emitting diode 5 at least indirectly pulsed and to evaluate a corresponding sensor signal originating from the photosensor 6. For this purpose, the control unit 10 has corresponding analog and / or digital interfaces. If the sensor signal exceeds a scattered light limit, an alarm message is output.

The fire detector 1 shown finally has an essentially rotationally symmetrical or mirror-symmetrical outer contour with respect to the constructive main axis or axis of symmetry SA of the fire detector 1.

FIG. 2 shows a plan view of the detector hood 4 with the central opening OP along the in FIG. 1 line of sight II. Like the FIG. 2 shows, are all components TS, 6 ', 7, 8, MIC, LED in the projected representation within the opening OP. In addition, aligned in this projected representation of the vertex SP and the axis of symmetry SA of the fire detector 1 with the center of the opening OP.

FIG. 3 shows a second embodiment with a formed in a gap ZW between the detector hood 4 and the attachment body A light trap LF according to the invention.

In contrast to the previous embodiment, the fire detector 1 has a receptacle AF for preferably detachable attachment of the detector 1 to a mounting base MS. The latter is typically attached to the ceiling. The detector 1 is not connected to its connection side AN on one attached detector base, which is typically attached to the ceiling. Furthermore, the detector hood 4 is designed in such a way that there is a gap ZW between the seating body A and the detector hood 4, which space acts according to the invention as a light trap LF. For this purpose, a recess AU is present in the attachment body and optionally in the circuit carrier 9. Thereby, the reflected light beam L or the light cone is passed through the recess AU into the gap ZW. For deflecting the reflected light beam L, the placement body A has a correspondingly shaped reflector surface RF, such as a "black" mirror. Preferably, the inside of the gap ZW has light-absorbing structures, such as a black paint.

In the example of FIG. 3 the opening OP is arranged at the vertex SP of the detector hood 4. In the opening OP, a temperature sensor TS for detecting the current ambient temperature T in the immediate vicinity of the fire detector 1 is arranged. The thermistor TS is attached to the largely direction-independent temperature detection at a central position on the vertex SP of the fire detector 1. The electrical contacts of the thermistor TS are contacted directly with the circuit carrier 9.

Furthermore, the detector hood 4 has a convex outer contour on its outer side AS. The detector hood 4 has an approximately equal wall thickness in the range of 1 to 2 mm.

FIG. 4 shows a third embodiment with a centrally located photosensor 6 and with an opposite focusing element FOC according to the invention. The focusing element FOC has such a focusing geometry that the scattered light emitted by the scattered light center Z and directed in the opposite direction to the photosensor 6 is focused and reflected in the direction of the photosensor 6. This advantageously increases the amount of light that the photosensor 6 receives from the scattered light volume SZ for the optical smoke detection.

In this case, the scattered light reaching from the scattered light center Z to the focusing element FOC also has approximately the same scattering angle as the scattered light reaching the photosensor 6 directly from the scattered light center Z. The focusing element FOC may be a mirror surface as described above. Preferably, it is a "black" mirror, i. a smooth, shiny surface, which is formed in the black plastic of the base body G. Preferably, the focusing element FOC comprises the contour of a part of an ellipsoid of revolution whose first focal point lies in the scattered light center Z and whose second focal point lies in the immediate region in front of the photosensor 6.

FIG. 4 further shows a formed in the radial outer region RA of the body G funnel TR as a light trap LF according to the invention. With DL a passage opening in an inner wall IW of the base body G is indicated, through which the light beam R, B enters the hopper TR.

FIG. 5 shows a plan view of the fire detector 1 according FIG. 4 along the viewing direction V marked there. It can now be seen in detail how the light beam L passes through the measuring space IR of the measuring chamber M and through the central area of the detector 1 into the light trap LF. The light beam L thereby intersects the main axis SA of the detector 1. The light trap LF is formed or formed in a cavity of the radial outer region RA of the main body G. The radial outer region RA of the main body G is limited by an inner wall IW, by which the optical measuring chamber M itself is limited. In the inner wall IW and the passage opening DL is recessed, through which the light beam L passes. The light trap LF has the form of a funnel TR, which extends around the main axis SA of the detector 1 in the radial outer region RA of the body G and the input side passes into a tubular bend, the entire region of the bend then directly the incident light beam L opposite. All light rays of the light beam L are then through the inner contour of the light trap LF in lateral, coaxial direction to the main axis SA of the detector 1 in the funnel TR of the light trap LF inside reflected. The light rays then run dead after repeated lossy reflection finally in the ever-narrowing funnel TR dead.

FIG. 6 shows a plan view of the fire detector 1 according FIG. 4 by way of example two funnels TR formed in the radial outer region RA of the main body G as a light trap LF. In this case, the light trap LF, which is twice as large, allows even more efficient light attenuation. For this purpose, SCH designates a cutting edge in the passage opening DL, which separates the two funnels TR from one another.

FIG. 7 shows a fourth embodiment with a focusing element FOC of three optically reflective, adjacent segments according to the invention. Each segment in this case is part of an ellipsoid of revolution whose first focal point lies in the scattered light volume and whose second focal point lies directly in front of the photosensor. This makes a special compact design possible.

In the lower part of the FIG. 7 the central opening OP in the detector hood 4 is covered by a dome DOM, leaving a plurality of radially outer, not further designated inlet openings. The DOM serves as a mechanical protection for a temperature sensor TS, which projects through the opening OP into the DOM. The inlet openings allow the passage of ambient air, so that a temperature detection by the temperature sensor TS is possible.

FIG. 8 shows a fifth embodiment with a plurality of circumferentially distributed ultrasound transmitters US and with a microphone MIC according to the invention. They are aligned such that they radiate in operation in the direction of a mounting surface MF, to which the fire detector 1 is attached. In the right part of the FIG. 8 Furthermore, a mounting base MS is shown, the radially as far outward extends, that the ultrasonic beam incident there is completely reflected from the surface of the mounting base MS. In particular, the surface of the mounting base MS, at least in the region of the impact of the respective ultrasound beam is flat and smooth.

Several ultrasonic transmitters US and ultrasonic receivers may be arranged on the circuit carrier, preferably at the radially outer end of the circuit carrier 9 and preferably alternately in the circumferential direction. Both the ultrasound transmitters US and the ultrasound receivers are acoustically aligned "obliquely" with the mounting surface MF. This is achieved in the present case by a respectively formed on the base body G reflection surface REF for ultrasonic waves UW. The control unit 10 of the fire detector 1 is set up to control the respective ultrasound transmitters for emitting an acoustic signal in the direction of the mounting surface MF, to temporally evaluate a respective ultrasound signal originating from the ultrasound receivers and reflected in the vicinity of the fire detector 1 and to output a fault message, if a detected object is within a predetermined distance around the fire detector 1.

As an alternative to the ultrasound receivers, as in the present example, a microphone MIC for receiving the ultrasound waves UW may be provided, which is arranged centrally at the vertex SP of the detector hood 4.

For both alternatives, advantageously larger objects, such as partitions or built-in cabinets, can be detected in the surroundings of the fire detector 1, which may possibly be flow-shielding for smoke or combustion gases to be detected.

Finally, the reference numeral N denotes an insect screen or a net which prevents the penetration of insects and larger dust particles into the interior of the optical measuring chamber.

In the example of FIG. 8 the indicator LED LED is arranged on the inside LI of the circuit substrate 9. It shines in the opposite direction, ie in the direction of the circuit substrate 9 and through a through hole DO in the circuit substrate 9 through and further out into the environment of the fire detector 1. The light emitting diode LED is an example of the type Gullwing. Likewise, the other sensors, such as photosensor 6 ', the heat radiation sensor 8, the gas sensor 7, the temperature sensor TS and the microphone MIC on the inside LI of the circuit substrate 9 may be arranged and through a corresponding passage opening OF in the circuit substrate 9, the respective measurement in the Detect environment of the fire detector 1. Similarly, the photosensor 6 of the fire sensor 5, 6 may be arranged on the outside LA of the circuit substrate 9 and be optically aligned by a corresponding passage opening DO in the direction of the measuring chamber IR of the measuring chamber M.

LIST OF REFERENCE NUMBERS

1

Fire detectors, smoke detectors, danger detectors,

2

detector housing

3

Headers

4

Detector hood, cap

5

LED, light transmitter, dual LED

6

Photosensor (smoke detection)

6 '

Light receiver (brightness sensor)

7

Gas sensor, semiconductor flue gas sensor

8th

Thermal radiation sensor, thermopile

9

Circuit carrier, printed circuit board

10

Control unit, microcontroller

11

Lens, optical element

A

Aufsetzkörper

FROM

Cover, lens

AF

admission

AT

terminal side

AS

light absorbing structures

AU

recess

BL

cover

DL

Port

DO

Through opening

DOM

Dom, central dome

e

reception area

FOC

Focusing element, mirror, elliptical mirror

G

Main body, measuring chamber bottom

GI

Inside of the body

IR

Measuring room, interior

IW

Inner wall, inner wall

HA

Outside of the detector hood

HI

Inside of the detector hood

K

terminals

L

Light beam, light cone

LA

PCB outside

LAM

slats

LED

Indicator, indicator LED

LI

PCB inside

LF

light trap

M

measuring chamber

MF

Mounting surface, ceiling

MIC

Microphone, ultrasound microphone

MS

mounting base

N

Net, insect repellent

OF

Smoke inlet opening

OIL

Optical lens

operating room

Opening, window

RA

radial outside area

RF

Reflector surface for light bundles

REF

Reflection surface for ultrasonic waves

S

Mirror surface, mirror

SA

Symmetry axis, constructive main axis

SCH

cutting edge

SP

Vertex, vertex

TS

Temperature sensor, thermistor, NTC

TR

Funnel, paraboloid

US

Ultrasonic sensor, transceiver, US transmitter

UW

Ultrasonic waves, acoustic signal

W

Detection range, optical detection range

Z

Stray light center, cutting volume, measuring volume

ZW

gap

Claims (15)

1. Fire alarm with a printed circuit board (9) and with a measurement chamber (M) communicating with the ambient air, wherein the measurement chamber (M) comprises a fire sensor (5, 6) for detecting a fire parameter, wherein the measurement chamber (M) is accommodated in an alarm housing (2) of the fire alarm, wherein the measurement chamber (M) comprises a base body (G) and an opposing attachment element (A) with a measurement space (IR) embodied therebetween, wherein the base body (G) is embodied for attachment to a mounting surface (MF), in particular to a detector base (MS), wherein the printed circuit board (9) rests against the attachment element (A) with an inner side (L1) facing the measurement space (IR), wherein at least one further sensor (TS, 6', 7, 8, MIC) in each case for detecting a measured variable in the surroundings of the fire alarm is arranged on an outer side (LA) opposing the inner side (L1) of the printed circuit board (9) and/or an indicator LED (LED) for optically outputting an operation status of the fire alarm is arranged in the surroundings of the fire alarm, and wherein the printed circuit board (9) is provided for arrangement of the fire sensor (5, 6) and the at least further sensor (TS, 6', 7, 8, MIC) and/or the indicator LED (LED).
2. Fire alarm according to claim 1, wherein the alarm housing (2) comprises a base housing (3) and an alarm cover (4) with at least one inlet opening (OF) embodied therebetween, wherein the at least one inlet opening (OF) is provided to allow fire gases and smoke particles to pass into the measurement chamber (M) of the fire alarm, wherein the alarm cover (4) has a cover outer side (HA) and a cover inner side (HI) opposing the latter, wherein the printed circuit board (9) rests on the cover inner side (HI) or wherein the printed circuit board (9) is distanced from the cover inner side (HI) by a maximum distance A of 1.5 cm, and wherein the at least one further sensor (TS, 6', 7, 8, MIC) and/or the indicator LED (LED) opposes an opening (OP) in the alarm cover (4) or projects into this opening (OP) or through this opening (OF) .
3. Fire alarm according to claim 1 or 2, wherein the fire alarm has a control unit (10) arranged on the printed circuit board (9), wherein the control unit (10) is connected to the fire sensor (5, 6) for detecting a fire parameter and to the at least one further sensor (TS, 6', 7, 8, MIC) for detecting the respective measured variable and/or to the indicator LED (LED) for optically outputting the operation status, and wherein the control unit (10) has an interface and is designed to detect a respective item of sensor information by means of the interface and/or by means of the interface to output a respective alarm message when impermissibly deviating from a respective detected sensor measured value.
4. Fire alarm according to one of the preceding claims, wherein the alarm cover (4) has an opening (OP) at a peak (SP) of the alarm cover (4) and wherein the outer side (LA) of the printed circuit board (9) opposes the opening (OP).
5. Fire alarm according to one of claims 1 to 4, wherein the opening (OP) in the alarm cover (4) is provided with a cover (AB), which is transparent for electromagnetic radiation in the wavelength range of 400 nm up to 25 µm.
6. Fire alarm according to one of claims 2 to 4, wherein at least the thermal radiation sensor (8) is arranged on the printed circuit board (9), and wherein the opening (OP) in the alarm cover (4) is provided with a cover (AB) which is only transparent for average infrared radiation in the wavelength range of 2 µm to 25 µm.
7. Fire alarm according to one of the preceding claims, wherein the fire sensor (5, 6) comprises a light-emitting diode (5) and a photosensor (6) and wherein the light-emitting diode (5) and the photo sensor (6) are arranged in a scattered light arrangement for optical smoke detection in accordance with the scattered light principle, and/or wherein the light-emitting diode (5) and the photosensor (6) are arranged opposite one another for optical smoke detection in accordance with the extinction principle.
8. Fire alarm according to claim 7, wherein the light-emitting diode (5) and the photosensor (6) are aligned optically with a shared scattered light volume (Z) within the measurement space (IR) and wherein the photo sensor (6) is arranged on the printed circuit board (9) such that a main axis (SA) which extends through the centre of the fire alarm extends through both the scattered light volume (Z) and also through the photo sensor (6).
9. Fire alarm according to claim 7 or 8, wherein the light-emitting diode (5) and the photo sensor (6) are arranged on the printed circuit board (9) and aligned such that these each have an optical axis which extends at least approximately orthogonally to the printed circuit board (9), wherein one part of the inner side (GI) of the base body (G) has a reflecting surface (S), which opposes the light-emitting diode (5), and wherein the reflecting surface (S) has a mirror geometry of this type, such that a cone of light (L) of the light-emitting diode (5) intersects a receiving region (E) of the photosensor (6) in a scattered light volume (Z) within the measurement space (IR) of the measurement chamber (M).
10. Fire alarm according to claim 9, wherein one part of the inner side (GI) of the base body (G) has a focussing element (FOC), which opposes the photosensor (6) and which has a focussing geometry such that scattered light is reflected out of the scattered light volume (Z) in the direction of the photosensor (6).
11. Fire alarm according to claim 10, wherein the focussing element (FOC) has a number of segments which reflect optically and adjoin one another, wherein each segment is part of an ellipsoid, in particular a rotational ellipsoid, the first focal point of which lies in the scattered light volume (Z) and the second focal point of which lies directly in front of the photosensor (6).
12. Fire alarm according to one of claims 9 to 11, wherein the reflecting surface (S) opposing the light-emitting diode (5) has a mirror geometry such that the cone of light (L) of the light-emitting diodes (5) traverses the measurement space (IR) and leads into a light-absorbing light trap (LF).
13. Fire alarm according to claim 12, wherein the light trap (LF) is shaped in the form of a funnel (TR) in the base body (G) and wherein the funnel (TR) in a radial outer region (RA) of the base body (G) extends substantially coaxially about a main axis (SA) extending through the centre of the fire alarm.
14. Fire alarm according to one of the preceding claims,

    - wherein a plurality of ultrasound emitters (US) are arranged on the printed circuit board (9) and are aligned such that during operation these radiate in the direction of a mounting surface (MF), to which the fire alarm is attached,

    - wherein a plurality of ultrasound receivers or a plurality of ultrasound transceivers is arranged on the printed circuit board (9) in each case as a structural unit comprising an ultrasound emitter (US) and an ultrasound receiver,

    wherein the ultrasound receiver is aligned in the direction of the mounting surface (MF) in order to detect ultrasound waves (UW) during operation from this direction or

    - wherein at least one microphone (MIC) is arranged as a further sensor on the printed circuit board (9) such that this opposes the opening (OP) in the detector cover (4), projects into this opening or through this opening (OP), wherein the opening (OP) is preferably arranged at the peak (SP) of the detector cover (4), and

    - wherein the control unit (10) is designed to activate the respective ultrasound emitter (US) for emitting an acoustic signal (UW) in the direction of the mounting surface (MF), to evaluate in terms of time an ultrasound signal originating from the ultrasound receivers or from the microphone (MIC) and reflected onto objects in the environment of the fire alarm, and to output a fault indication if an object is disposed within a predetermined distance from the fire alarm.
15. Fire alarm according to claim 14, which has at least one reflection surface (REF) embodied preferably in the base body (G) in the beam path from the respective ultrasound emitter (US) to the mounting surface (MF).

Images