EP3474249A2 - Dispositif de mesure destiné à la mesure de particules - Google Patents

Dispositif de mesure destiné à la mesure de particules Download PDF

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Publication number
EP3474249A2
EP3474249A2 EP18192540.5A EP18192540A EP3474249A2 EP 3474249 A2 EP3474249 A2 EP 3474249A2 EP 18192540 A EP18192540 A EP 18192540A EP 3474249 A2 EP3474249 A2 EP 3474249A2
Authority
EP
European Patent Office
Prior art keywords
optical
signal
measuring
measuring chamber
optical path
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP18192540.5A
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German (de)
English (en)
Other versions
EP3474249A3 (fr
Inventor
Thomas Hanses
Tjark Windisch
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP3474249A2 publication Critical patent/EP3474249A2/fr
Publication of EP3474249A3 publication Critical patent/EP3474249A3/fr
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
    • G08B17/103—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device
    • G08B17/107—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using a light emitting and receiving device for detecting light-scattering due to smoke
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/18—Prevention or correction of operating errors
    • G08B29/20—Calibration, including self-calibrating arrangements
    • G08B29/24—Self-calibration, e.g. compensating for environmental drift or ageing of components

Definitions

  • a smoke detector is already known in which a lamp is provided which radiates a beam of visible or infrared light through a room in which the presence of smoke is to be detected.
  • a photocell is also provided, which responds to the light of the lamp and which is arranged so that it can not be hit by a light beam directly, but only by scattered by the smoke to be detected light.
  • it is checked whether actually light from the lamp arrives at the photocell, in which case an alarm device is triggered.
  • the measuring device for particle measurement, in particular in the form of a smoke detector, has a measuring chamber, a transmitting device for generating an optical signal for feeding into the measuring chamber and a receiving device for receiving the optical signal from the measuring chamber. So that particles, in particular smoke, can be detected, the measuring chamber is opened in a suitable manner to an atmosphere surrounding the measuring device. For example, an opening is provided through which ambient air can penetrate. In addition to a desired penetration of the particles to be measured or the smoke to be measured but it comes during a particular long-term, multi-year use of the measuring device that unwanted ambient dust penetrate into the measuring chamber and can also be reflected on the transmitting device and the receiving device.
  • a calibration device which, via an intensity measured by a signal receiver, performs a calibration of the receiving device via a second optical path available in addition to a first optical path, by means of which the measurement of the particles takes place.
  • This can be a reduction in intensity by contamination of the transmitting device and / or the receiving device are measured with ambient dust.
  • the result of this measurement can then be used for a particle measurement as a correction variable in order to reduce the influence of a measurement result of the particle measurement by contamination of the ambient dust measuring device.
  • the first optical path is designed such that in a normal case no direct and ideally also no reflected light from the transmitting device to the receiving device, when there are no particles in the measuring chamber. If, on the other hand, particles are present in the measuring chamber in the first optical path, the light is scattered and deflected by the transmitting device to the particles, so that the light can then reach the receiving device.
  • the second optical path is ideally designed so that the signal source is directly visible from the signal receiver or that the light is deflected in such a way that the light from the signal source partially reflects the signal source Signal receiver also achieved in a state in which there is no smoke in the measuring chamber.
  • a triggering threshold for a smoke detector in accordance with shadowing due to contamination such that a constant predetermined concentration of smoke particles in the measuring chamber triggers an alarm. Furthermore, it is also possible in this way to compensate for an age-related degradation of the transmitting device and / or the receiving device. For a safe triggering of a smoke detector or an accurate particle measurement is also possible if the device has been in use for several years and thus it has come to a dust entry into the measuring chamber or aging of the installed components.
  • an optical switching device which establishes the second optical path for a calibration operation. This can avoid that, during normal operation, light can reach the receiving device via the second optical path and thus possibly falsify a measurement result. It is particularly easy to produce a corresponding optical switching device via an electrically switchable, for example electrochromic, mirror or via a mechanically drivable, movable mirror.
  • the signal source can be particularly advantageously provided as the transmitting device and / or the signal receiver as the receiving device.
  • the measuring operation is interrupted for a short time and the optical switching device is switched so that with the already existing in the measuring device components of transmitting device and receiving device calibration can be performed.
  • the signal receiver it is advantageous for the signal receiver to be designed as a separate, but separate, optical receiving device that is identical in construction to the receiving device.
  • a sensitivity of the Signal receiver can be adapted in particular to an intensity measurement. If the signal receiver is mounted in a corresponding environment adjacent to the receiving device, it can be assumed that the signal receiver is contaminated in a corresponding manner. Thus, if a corresponding decrease in a reception intensity is detected in the signal receiver, then it can be assumed that the receiving device itself is contaminated in a similar manner and that the intensity is reduced in a similar manner.
  • the measuring chamber advantageously has, for the first optical path, an optical trap for suppressing direct irradiation of the optical signal from the transmitting device to the receiving device and for suppressing reflections of the optical signal from the transmitting device to the receiving device caused by the measuring chamber.
  • an optical trap for suppressing direct irradiation of the optical signal from the transmitting device to the receiving device and for suppressing reflections of the optical signal from the transmitting device to the receiving device caused by the measuring chamber.
  • the second optical path is at least partially outside the measuring chamber.
  • the measuring chamber for the calibration measurement can be bypassed, so that optionally a representation of the second optical path is simplified.
  • the second optical path is a direct optical connection between the signal source and the signal receiver or it is via a Optical waveguide or realized one or more mirrors, so that a high amount of light of the signal source can be forwarded to the signal receiver.
  • An advantageous, cost-effective design of transmitting device and receiving device is possible in a realization as a semiconductor device, for example as a light emitting diode or photocell.
  • a reflection is determined by introduced into the measuring chamber pollution.
  • particles possibly lead to a light scattering in the direction of the receiving device, but also particles that have been deposited on a wall of the measuring chamber.
  • the light scattered by these particles in an undesired manner causes more light to reach the receiving device even in a quiescent state.
  • the sensitivity of the measuring device increases and optionally indicates a higher particle value or rather triggers a smoke alarm.
  • it may be provided to adapt a calibration of the measuring device to this influencing with a correspondingly long time constant, and in particular to raise a limit value for smoke emission.
  • the present invention can be used for any measuring device in which particles are detected optically by detecting the light scattering by these particles.
  • the application is advantageous for smoke detectors, since smoke detectors have long been used in residential or business premises for use and thus a maintenance-free, long-term use is desirable. Therefore, the present invention is explained below using the example of a smoke detector.
  • FIG. 1 a first embodiment of a measuring device in the form of a smoke detector 10 is shown.
  • the smoke detector 10 has a measuring chamber 11 into which air can penetrate through an opening 12 from the environment.
  • the measuring chamber 11 is designed such that air can flow through the measuring chamber 11.
  • a fan for supplying outside air into the measuring chamber 11.
  • the opening 12 is provided with a cap 13 such that as far as possible no ambient light can penetrate into the measuring chamber 11.
  • a transmitting device 21 is arranged, which generates an optical measuring signal, for example in a visible or in an infrared range.
  • the transmitting device 21 is in this case designed in particular as a light-emitting diode.
  • the transmitting device 21 is controlled by a control unit 30. In particular, it is energized at short notice, for example for half a second, to emit a light signal.
  • a receiving device 22 is arranged in the measuring chamber 11.
  • the construction is in the FIG. 1 shown simplified, wherein ideally in the event that there are no particles in the measuring chamber 11, as little as possible or very little light passes through reflections on the walls of the measuring chamber 11 from the transmitting device 21 to the receiving device 22. On the other hand, if particles are present in the measuring chamber 11, then these particles scatter the light in any spatial directions, so that in this case also light of the transmitting device 21 can reach the receiving device 22.
  • the receiving device 11 is designed in particular as a semiconductor element, for example as a photosensitive resistor or as a photocell.
  • a signal of the receiving device 20 is also evaluated by the control unit 30.
  • the control unit 30 has a computing unit 31 which both controls the transmitting device 21 and also evaluates signals of the receiving device 22. From the evaluation signal of the receiving device 22, the arithmetic unit 31 calculates a particle concentration or accesses a calculation rule which is stored in a memory 32 of the control unit 30, or compares a measured intensity value with a limit value, which is stored, in particular, in a memory 33.
  • the memories 32, 33 may also be different memory areas of a memory.
  • a limit value of the intensity predefined in the memory 33 is exceeded when a signal is emitted by the transmitting device 21 at the receiving device 22, then a minimum concentration of particles is present, which is regarded as critical.
  • the arithmetic unit 31 triggers an alarm.
  • the control unit 30 controls, for example, a loudspeaker 34 and / or an optical signal transmitter 35.
  • a first, indirect optical path is thus provided around the light trap 23 from the transmitting device 21 to the receiving device 22.
  • the transmission device 21 is provided as a signal source and the reception device 22 as a signal receiver.
  • the calibration operation is in regular Time intervals, for example once a day or once a week, driven by the arithmetic unit 31.
  • the control unit 30 is connected via a control line 24 with an optical switching device 25, which is arranged in the first embodiment in the measuring chamber 11. It is embodied, for example, as an electrically switchable electrochromic mirror or as a movable mirror, for example as a micromechanically movable mirror.
  • the mirror 25 is positioned such that it does not deflect light from the transmitting device 21 to the receiving device 22.
  • the reflective surface of the measuring chamber 11 away from a wall of the measuring chamber 11 to.
  • the mirror 25 is set to deflect the light emitted from the transmitting device 21 to the receiving device 22.
  • the second optical path is optionally guided through the measuring chamber 11.
  • a in the FIG. 1 dashed shown optical switching element 26 opens a second optical path 27 which leads from the transmitting device 21 at least partially outside the measuring chamber 11 to bypass the light trap 23 to the receiving device 22.
  • the optical switching element 26 is also designed as a diaphragm which opens or closes the optical connection.
  • the second optical path by means of light guides, which may also realize a non-linear optical connection for the second optical path of the transmitting device 21 to the receiving device 22 due to the light line in its interior and a possible flexibility ,
  • a direct optical connection if necessary via one or more light deflection elements between the transmitting device 21 as a signal source and the receiving device 22 as a signal receiver along the second optical path is established. It is done now an emission of an optical signal by the transmitting device 21 and a reception by the receiving device 22. An intensity of the received signal is recorded and compared with a stored in the memory 33 basic value in particular at the time of delivery or manufacture of the smoke detector 10. From a deviation from the measured value, an optionally existing reduction in the intensity due to contamination of the transmitting or receiving device 21, 22 is determined. A corresponding reduction of the intensity is stored in the memory 33 and used for subsequent processing in measuring operation. Either in this case the measured signal is corrected upwards by a factor corresponding to the shadowing due to contamination, or a limit value for triggering an alarm stored in the memory 33 is lowered.
  • FIG. 2 an alternative embodiment of a measuring device is shown.
  • a measuring device 40 has a measuring chamber 41 in an opening 42, wherein these components of the embodiment according to the FIG. 1 correspond. Accordingly, a control unit 30 corresponding control unit 43 is shown in simplified form.
  • a transmitting device 44 and a receiving device 45 are comparable to the FIG. 1 separated by a light trap 46 in the measuring chamber 41.
  • a signal receiver 47 Adjacent to the receiving device 45, a signal receiver 47 is arranged, which is identical in construction of the receiving device 45 in one embodiment. Ideally, the signal receiver 47 is exposed to the same atmosphere as the receiving device 45, so that air flowing into the measuring device 40 sweeps over both components.
  • a direct second optical path 48 is provided by the transmitting device 44 to the signal receiver 47, so that light can pass directly from the transmitting device 44 to the signal receiver 47 in a calibration operation. If an intensity measurement is now carried out, contamination on the components of the transmitting device 44 and of the signal receiver 47 leads to a reduction in intensity which can be measured.
  • the transmitting device 44 it is also possible, in addition to the transmitting device 44, to provide its own signal source 49, which is provided in the FIG. 2 indicated by dashed lines.
  • the light generated by the signal source 49 is radiated directly toward the signal receiver 47 to perform an intensity measurement.
  • FIG. 3 a further embodiment of a measuring device 50 is shown, which has a measuring chamber 51 with an opening 52.
  • a control unit 53 which is designed in accordance with the control unit 30, controls a signal source 54, a transmitting device 55, a receiving device 56 and a signal receiver 57.
  • the transmitting device 55 and the receiving device 56 are optically separated from one another by a light trap 58, so that the first optical path leads through the measuring chamber 51 and light only reaches the receiving device 56 when particles have been introduced into the volume of the measuring chamber 51.
  • a direct optical connection is provided as a second optical path, so that light is conducted through the measuring chamber 51 in the calibration operation from the signal source 54 to the signal receiver 57.
  • the control unit 53 carries out both a measuring operation with the transmitting device and the receiving device 55, 56 as well as a calibration operation with the signal source 54 and the signal receiver 57.
  • an inventive method of calibration is shown.
  • switching is made from a measuring mode to a calibrating mode.
  • the initialization step 60 for a calibration is initiated only if there is no alarm case.
  • a first calibration step 61 an actually measured intensity is determined, with which the signal receiver receives a signal provided by the signal source.
  • the measured signal intensity is compared with a base value stored in a memory of the control device, which is measured or determined in particular during a production of the sensor and then stored in the memory. If appropriate, a correction factor for contamination of transmitting device and receiving device is directly determined and stored therefrom.
  • a measured value along the first optical path from the transmitting device to the receiving device is determined. This measurement is virtually a dark value for a smoke sensor, if no smoke is contained in the measuring chamber.
  • the measured value is compared with a base value determined or measured during the production of the sensor and stored in the memory. If appropriate, a correction factor for additional scattering as a result of dust in the measuring chamber is also directly determined and stored therefrom.
  • a subsequent determining step 63 if not yet seen, the corresponding correction factors are determined and the product of these correction factors is calculated, e.g. a product of the sender and receiver fouling factor and the correction factor for additional scatter due to dust in the measuring chamber.
  • a quotient of a measured value and a basic value during production is preferably used as the basis.
  • This correction factor multiplies a stored base limit to set a new limit to determine a new measurement threshold for the smoke alarm determination device.
  • a subsequent test step 64 it is checked whether the correction value remains below a predetermined limit. If so, the new correction value is committed in the memory and used for a subsequent measurement.
  • a subsequent measuring step 65 is switched to a normal measuring operation. If the correction factor deviates from a basic value by a predetermined amount, for example 5% to 10%, an error output step 66 is referred to, since the measuring device may no longer function correctly as a result of excessive contamination.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Fire-Detection Mechanisms (AREA)
EP18192540.5A 2017-09-28 2018-09-04 Dispositif de mesure destiné à la mesure de particules Withdrawn EP3474249A3 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102017217280.0A DE102017217280A1 (de) 2017-09-28 2017-09-28 Messeinrichtung zur Partikelmessung

Publications (2)

Publication Number Publication Date
EP3474249A2 true EP3474249A2 (fr) 2019-04-24
EP3474249A3 EP3474249A3 (fr) 2019-07-10

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EP18192540.5A Withdrawn EP3474249A3 (fr) 2017-09-28 2018-09-04 Dispositif de mesure destiné à la mesure de particules

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DE (1) DE102017217280A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102021208901A1 (de) 2021-08-13 2023-02-16 Robert Bosch Gesellschaft mit beschränkter Haftung Verfahren zum Überwachen einer optischen Messeinrichtung und optische Messeinrichtung
DE102022134456A1 (de) 2022-12-22 2024-06-27 Carl Zeiss Spectroscopy Gmbh Spektrometer zur spektralen Analyse einer Probe

Family Cites Families (5)

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Publication number Priority date Publication date Assignee Title
DE3831654A1 (de) * 1988-09-17 1990-03-22 Hartwig Beyersdorf Optischer rauchmelder
US5617077A (en) * 1995-05-03 1997-04-01 Pittway Corporation Testable photoelectric detector
DE102007039401B4 (de) * 2007-08-21 2012-07-12 Hekatron Vertriebs Gmbh Rauchmelder mit Verschmutzungsüberwachung
DE102009054141A1 (de) * 2009-11-13 2011-05-19 Job Lizenz Gmbh & Co Kg Verfahren zum Prüfen der Funktion eines Rauchmelders
US10078948B2 (en) * 2016-01-26 2018-09-18 Honeywell International Inc. Smoke detector with a double optical chamber

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DE102017217280A1 (de) 2019-03-28
EP3474249A3 (fr) 2019-07-10

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