Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
  • G08B17/00—Fire alarms; Alarms responsive to explosion

Definitions

• the present invention relates to fire detectors including non-volatile memory. More particularly, the invention relates to a fire detector comprising:
• a central unit comprising a non-volatile memory in which a code representative of at least one characteristic element specific to said fire detector is recorded
• a fire sensor which measures a physical quantity whose variations make it possible to detect the existence of a fire in the vicinity of the fire detector, this fire sensor supplying the central unit with an analog electrical signal, said measurement signal, which has a value representative of the physical quantity measured by the fire sensor, the aforementioned characteristic element including a normal value iO of the measurement signal in the absence of fire.
• a fire detector is disclosed in the document: Research Disclosure No. 357, January 1994 (Emsworth, GB, "Smoke detector with dirty chamber signal").
• Fire detectors of the type in question must be maintained at regular time intervals in order to remain reliable.
• maintenance services usually note the date of the last dismantling of a fire detector for maintenance, without always systematically and reliably checking the effectiveness of this maintenance. Consequently, if the periodic maintenance of a fire detector has been poorly done, it can then give unreliable indications at least until its next dismantling date for maintenance.
• the present invention aims in particular to overcome these drawbacks.
• a fire detector of the kind in question is essentially characterized in that the fire detector also comprises interface means allowing access to the content of the memory. retentive without dismantling the fire detector, (that is to say in particular without removing it from its base, or without unscrewing it from the ceiling, or without opening its case), in that the retentive memory also includes dates on which maintenance operations on said fire detector were carried out, and in that the central unit is programmed to compare the measurement signal with the normal value iO of the measurement signal each time it receives means of interface an instruction to record a maintenance date, and to refuse this recording if the measurement signal is not between iO - ⁇ l and iO + ⁇ 2, where ⁇ l and ⁇ 2 are predetermined values.
• maintenance services can easily access at least the last preventive maintenance date for each fire detector, without having to dismantle the fire detector, which is often difficult to access since it is placed high up. .
• Maintenance services can therefore easily determine reliably whether a particular fire detector should be subject to preventive maintenance.
• the new maintenance date is not written to the non-volatile memory of the detector unless this maintenance has made it possible to reduce the measurement signal in the absence of fire to a value close enough to the normal value iO, it is easy to identify fire detectors for which maintenance has been poorly done or is insufficient, and this without waiting for the next preventive maintenance. As a result, the reliability of fire detection is improved.
• the interface means comprise a connector connected to the central unit, the connector being able to receive a complementary connector connected to an external device in order to make this external device communicate with the central unit;
• the interface means comprise a communication link between the fire detector and an alarm center: this embodiment is particularly advantageous, insofar as it makes it possible to know, from the alarm center, at least the date of the last maintenance of all the fire detectors connected to this alarm center;
• the aforementioned characteristic element also includes a date of manufacture of said detector
• the non-volatile memory also contains, for each maintenance date, the value of the measurement signal transmitted to the central unit by the fire sensor when recording said measurement date;
• the normal value iO of the measurement signal is a value measured in the absence of fire for the fire sensor in question, during its manufacture or its first commissioning.
• the single figure represents a fire detector according to an embodiment of the invention, connected to an alarm center and capable of being connected to an external interface box.
• the fire detector 1 according to the invention comprises a microprocessor 2 including a non-volatile memory 2a, in particular of the EEPROM type. More generally, the fire sensor 1 comprises a central unit which includes a programmable electronic circuit such as a microprocessor and a non-volatile memory which may or may not be included in the microprocessor.
• the microprocessor 2 has an analog input 2a which is connected to a fire sensor 3, which fire sensor measures a physical quantity, the variations of which make it possible to detect the existence of a fire in the vicinity of the fire detector.
• the fire sensor 3 can be an ionic smoke sensor, an optical smoke sensor, a thermal sensor, or the like.
• the fire sensor 3 sends to the analog input 2a of the microprocessor an analog electrical signal i, called the measurement signal, the value of which is representative of the physical quantity measured by the fire sensor.
• the value of the signal i which is representative of the physical quantity measured can be for example the intensity or the voltage of this signal.
• the microprocessor 2 compares the measurement signal i to a normal value iO of this measurement signal in the absence of fire, and when the measurement signal i is sufficiently distant from its normal value iO, the microprocessor 2 determines l existence of a fire in the vicinity of the fire detector 1, and it reacts for example by sending a alarm message to an alarm center 4, via a link 5, which preferably also allows messages to be sent from the alarm center 4 to the microprocessor 2.
• the non-volatile memory 2a of the microprocessor 2 includes not only the normal value iO mentioned above, measured just after the manufacture of the fire detector 1 or after its first commissioning, but also the date of the maintenance operations undergone by the detector, or at least the date of the last maintenance operation. In addition, the non-volatile memory 2a preferably also includes the date of manufacture and the serial number specific to the fire detector 1.
• alarm center 4 which can be provided, for example, with a screen 4a and a keyboard 4b.
• the fire detector 1 has a connector 6 connected to the microprocessor 2.
• the connector 6 During the maintenance operations of the fire detector 1, when the said detector is removed, it is thus possible to connect to the connector 6 an additional connector 7 which is connected to an interface box 8 by means of a cable 9, the interface box 8 comprising for example a screen 8a and a keyboard 8b.
• Microprocessor 2 is programmed to compare the value of the measurement signal i to said normal value iO when said microprocessor receives from the interface box 8 the order to record the date of maintenance.
• the microprocessor 2 is programmed to refuse the recording of the maintenance date in the non-volatile memory 2a, and to send the interface box 8 a message indicating this refusal.
• the microprocessor 2 can control the efficiency of the maintenance operations, and this efficiency is also controllable from the alarm center 4 if the fire detector has been reassembled despite the refusal to record the last maintenance date.

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• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Fire Alarms (AREA)
• Fire-Detection Mechanisms (AREA)

Applications Claiming Priority (3)

Publications (2)

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ID=9465924

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• 1994
  • 1994-07-29 FR FR9409476A patent/FR2723236B1/fr not_active Expired - Lifetime
• 1995
  • 1995-07-27 ES ES95926437T patent/ES2118611T3/es not_active Expired - Lifetime
  • 1995-07-27 EP EP95926437A patent/EP0772850B1/de not_active Expired - Lifetime
  • 1995-07-27 WO PCT/FR1995/001011 patent/WO1996004623A1/fr active IP Right Grant
  • 1995-07-27 JP JP8506243A patent/JPH11509339A/ja active Pending
  • 1995-07-27 US US08/776,424 patent/US5815075A/en not_active Expired - Lifetime
  • 1995-07-27 DE DE69502400T patent/DE69502400T2/de not_active Expired - Fee Related

Non-Patent Citations (1)

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