WO2008117016A1 - Détecteur - Google Patents

Détecteur Download PDF

Info

Publication number
WO2008117016A1
WO2008117016A1 PCT/GB2008/000876 GB2008000876W WO2008117016A1 WO 2008117016 A1 WO2008117016 A1 WO 2008117016A1 GB 2008000876 W GB2008000876 W GB 2008000876W WO 2008117016 A1 WO2008117016 A1 WO 2008117016A1
Authority
WO
WIPO (PCT)
Prior art keywords
detector
sensor
resistors
resistor
voltage
Prior art date
Application number
PCT/GB2008/000876
Other languages
English (en)
Inventor
Steven Ian Bennett
Don Brighenti
Joe Piccolo
Kimberly Babineau
Original Assignee
Thorn Security Limited
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 Thorn Security Limited filed Critical Thorn Security Limited
Priority to EP08718718A priority Critical patent/EP2140435B1/fr
Publication of WO2008117016A1 publication Critical patent/WO2008117016A1/fr
Priority to US12/568,423 priority patent/US8198997B2/en

Links

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B17/00—Fire alarms; Alarms responsive to explosion
    • 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
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
    • G08B21/02—Alarms for ensuring the safety of persons
    • G08B21/12—Alarms for ensuring the safety of persons responsive to undesired emission of substances, e.g. pollution alarms
    • G08B21/14—Toxic gas alarms
    • 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
    • G08B29/12—Checking intermittently signalling or alarm systems
    • G08B29/14—Checking intermittently signalling or alarm systems checking the detection circuits
    • G08B29/145—Checking intermittently signalling or alarm systems checking the detection circuits of fire detection circuits
    • 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

Definitions

  • This invention relates to a detector, and in particular to a fire detector.
  • a fire detector typically includes one or more sensing elements, such as an optical smoke sensing element, a CO sensor for detecting carbon monoxide, or a pyroelectric sensor for detecting the presence of a flame.
  • sensing elements such as an optical smoke sensing element, a CO sensor for detecting carbon monoxide, or a pyroelectric sensor for detecting the presence of a flame.
  • the problem with known fire detectors is that each type of sensing element tends to decay with time, without there being provided means for accurately establishing exactly how much the sensitivity of its sensing element has changed since installation. This problem is exacerbated where a fire detector is provided with two or more different types of sensor (for example an optical smoke detecting sensor and a CO sensor), which tend to decay at different rates, requiring more frequent manual inspection which is time consuming and expensive.
  • a fire detector sensor is associated with an EEPROM, in which case a manufacturing date code is entered into the EEPROM.
  • This manufacturing date code can then be interrogated by control and indicating equipment (CIE) which is provided to monitor and control the fire detector.
  • CIE control and indicating equipment
  • many fire detectors do not have EEPROMs associated with their sensors.
  • the term "date code" should be taken to mean a code representation of the period of time during which a particular sensor was manufactured. Typically, this period of time will be six months or one year.
  • An aim of the invention is to provide a fire detector that can provide a date code to a CIE at minimum cost.
  • the present invention provides a detector comprising a detector base and a sensor, first and second resistors connected in series, a DC voltage source connected to the resistors, and means for monitoring the voltage at the midpoint of a potential divider constituted by the series-connected resistors, wherein the first and second resistors are rated so that the midpoint voltage is indicative of a property of the sensor.
  • the first resistor is provided on the detector base, and the second resistor is associated with the sensor.
  • the senor is a separate item from the detector base, the second resistor being combined with the sensor.
  • the monitoring means and the voltage source are provided on the detector base.
  • the monitoring means is constituted by an A/D converter.
  • the detector base is provided with an AC control line for controlling a self-test of the sensor, the DC voltage from the DC voltage source being superimposed on the AC line.
  • the senor is a CO sensor for fire detection.
  • the sensor property is the date code of the sensor.
  • the detector further comprises a second sensor, the second sensor having a third resistor, the first and third resistors being connected in series, the DC voltage source being connected to the first and third resistors, and the second sensor being provided with means for monitoring the voltage at the midpoint of a potential divider constituted by the series-connected first and third resistors, wherein the first and third resistors are rated so that the midpoint voltage is indicative of a property of the second sensor.
  • the monitoring means of the second sensor is constituted by an A/D converter.
  • the second sensor is a separate item from the detector base, the third resistor being combined with the second sensor.
  • the second sensor is provided on the detector base. In either case, the property of the second sensor may be the date code of that sensor.
  • the invention also provides a detector system comprising a central control and a plurality of detectors as defined above.
  • the central control is provided with software for interrogating each of the detectors to request the monitoring means of each detector to return to the central control a signal indicative of said property of the sensor of that detector.
  • the invention further provides a detector arrangement comprising a plurality of detector systems as defined above, and a monitoring station provided with means for communicating with the central control of each of the detector systems.
  • a fire detector is constituted by a detector base 1 and a sensor 2.
  • the detector base is attached to a software-controlled CIE 3 by on-site wiring 4.
  • the CIE 3 is connectable wirelessly to a remote monitoring station 5.
  • the CIE 3 is associated with a plurality of other fire detectors (not shown), thereby constituting a central control for all the fire detectors.
  • the detector base 1 is provided with a control line 6 which is used to send a signal, via an AC control line 7, to the sensor 2 for carrying out a self-test of that sensor.
  • the detector base 1 is provided with an internal base resistor (IBR) 8, and the sensor 2 is provided with a select on manufacture (SOM) resistor 9.
  • An analogue-to-digital (AJO) converter 10 is provided in the detector base 1 for monitoring the midpoint voltage between the potential divider constituted by the two resistors 8 and 9.
  • the detector base 1 is provided with a DC voltage reference Vref, which is typically 5 volts.
  • the DC voltage reference Vref is applied to both the A/D converter 10 and the potential divider, so that an extra Vref line running to the sensor 2 is not required. This ensures that the only source of inaccuracy is the potential divider resistance tolerance ( ⁇ 1% ⁇ a 1 bit digitising error).
  • the resistors 8 and 9 can have values in the range from several kilohms to tens of megohms.
  • the IBR resistor 8 has a fixed value, which is common to all detector bases used in a fire detector system.
  • the value of the resistor 8 is chosen such that it is high enough to eliminate excessive currents when the SOM resistor 9 has a low value, but low enough such that the SOM resistor does not go beyond the usual range of resistor values whilst allowing the network to yield a wide dynamic range for the midpoint voltage.
  • Each of the SOM resistors 9 in the system has a value which is chosen in dependence upon the date of manufacture of the associated sensor 2.
  • the rating of the SOM resistor 9 of a given sensor 2 is chosen so that the midpoint voltage of the potential divider constituted by that resistor and the IBR resistor 8 of the associated detector base 1 represents the date code of that sensor.
  • the period of time covered by each date code may be six months, and each sensor 2 manufactured in that period will be provided with a SOM resistor 9 of the same value, and each sensor manufactured in any other six month period will be provided with a SOM resistor of a different value.
  • the midpoint voltage monitored by the A/D converter 10 of a given detector base 1 will provide an indication of the period in which the associated sensor 2 was manufactured.
  • the AC control line 7 forms part of the potential divider, the hardware interconnections for generating the date code are minimised.
  • the CIE 3 remotely interrogates each of the detectors in its system.
  • the A/D converter 10 of each detector then responds with a digital signal corresponding to the analogue midpoint value of the associated potential divider, thereby informing the CIE 3 of the period in which the associated sensor 2 was manufactured.
  • the CIE 3 will then calculate the time difference between the sensed manufacturing period and the interrogation date, and will inform an operator that maintenance is required if this difference exceeds a predetermined service interval. The operator will then be able to visit each detector which requires maintenance for replacement of the sensor 2 of that detector.
  • the CIE 3 would be programmed with regular maintenance intervals, and would provide an operator with an advance warning of all the sensors 2 in the system which are about to reach a "service required" interval.
  • the CIEs 3 are arranged to output operator alert signals to the remote monitoring station which, in turn, signals an appropriate operator for each of the systems under its control, hi practice, the remote monitoring station 5 is connected to the CIE 3 only when monitoring is to be carried out, say one every six months or once every year.
  • the detector 1 may be a CO sensor which typically has a more rapid decay time than other sensors (such as an optical smoke detecting sensor or a pyroelectric sensor) for use in fire detection. With such an arrangement, it is particularly important that regular maintenance is carried out, so that improved reliability of a fire detector system results.
  • sensors such as an optical smoke detecting sensor or a pyroelectric sensor
  • the invention is particularly useful where the fire detectors of a fire detection system are each provided with two different types of sensor, typically a CO sensor and an optical smoke detecting sensor.
  • a CO sensor typically a CO sensor
  • an optical smoke detecting sensor decays much more slowly than a CO sensor
  • maintenance of smoke detectors needs to be carried out substantially less frequently, so maintenance regimes which are typically arranged to monitor smoke detectors are liable not to provide good maintenance for CO sensors.
  • a second sensor 11 such as an optical smoke detecting sensor or a pyroelectric sensor, may be associated with the detector base 1.
  • This sensor 11 will also be provided with a SOM resistor which can be linked to an IBR.
  • An A/D converter will monitor the midpoint of the two resistors constituting the potential divider of the second sensor 11, in a similar manner to that described above.
  • the SOM resistor and the IBR resistor associated with the second sensor 11 are separate items from the SOM resistor 9 and the IBR resistor 8 of the sensor 2.
  • the A/D converter of the second sensor 11 can be a separate item, but could also be constituted by the same A/D converter 10 with, for example, appropriate signal switching.
  • the CIE 3 will be provided with signals representative of the date code of each of the two sensors 2 and 11 , so that an operator can be dispatched to maintain either of the sensors of any of the fire detectors in the system at an appropriate time.
  • the second sensor 11 could be provided on the detector base 1.
  • the sensor 2 is a separate item from the detector base 1 , and includes only the minimum amount (its SOM resistor and an associated calibration circuit element) hardware in addition to that required for actual sensing. Consequently, when the sensor 2 requires replacement, the cost of this is minimised. This is due to the date code (the period during which the sensor 2 was manufactured) being coded by the voltage derived from the potential divider, part of which is found in the replaceable sensor 2, and part in the detector base 1.
  • an accurate voltage reference for the potential divider is provided from the same source as that used for providing the A/D voltage reference, that the voltage representing the date code is superimposed as a DC voltage on an AC line, thereby minimising interconnections between the replaceable sensor 2 and the detector base 1, that remote interrogation of the detector base to indicate "end of lifetime” is done by the CIE 3, thereby eliminating the need for an operator to visit all the detectors in a fire detector system, and that predictive software, linked in with regular service intervals, is employed, so that "service required" warning signals are raised together during each service visit.
  • a fire detector system incorporating fire detectors of this type provides additional features to assist service personnel in monitoring and servicing the fire detectors of the system.
  • the system can produce a service report which includes the date code of each of the fire detectors. It also provides means for a service engineer to read the date codes of the fire detectors in a given system from the control panel of that system when the service engineer visits. In either case, the service engineer has the option of replacing sensors that will expire soon, so that he is not called back in the near future for a further service visit.
  • the invention could be adapted to cover information coding other than the date code (the period during which a sensor was manufactured). For example, if a sensor has to achieve a multiplicity of approvals, for sale in various different geographical areas, area codings could be provided in the same way as the date codes, to ensure that sensors sold into a given geographical area are the correct approved types for that area. This can be done in conjunction with the date code, if the change of period coding is made to coincide with the manufacturing period of a variant with a particular approval. Information coding could also cover other possibilities, such as model, type or version of sensors. It would also be possible to replace each SOM resistor 9 by two resistors in series, thereby allowing fine tuning of the network values for additional steps.
  • the IBR resistor 8 could be replaced by a potentiometer, a resistor array with a DP switch, or a breakable fuse array permitting selection of a combination of resistors.
  • monitoring of each of the detectors in a fire detection system can be carried out by a hand-held device.
  • the arrangement can be such that each of the detectors returns, to the CIE 3 and/or the hand-held device, a signal indicative of the date code of that detector.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Computer Security & Cryptography (AREA)
  • General Health & Medical Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Analytical Chemistry (AREA)
  • Chemical & Material Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fire Alarms (AREA)

Abstract

L'invention concerne un détecteur qui comprend une base de détecteur (1) et un capteur (2), des première et seconde résistances (8 et 9) reliées en série, une source de tension en courant continu (Vref) reliée aux résistances, et des moyens (10) pour surveiller la tension au point médian d'un diviseur de tension constitué par les résistances connectées en série. Les première et seconde résistances (8 et 9) sont calculées de telle sorte que la tension de point médian soit indicative de la date de fabrication du capteur (2).
PCT/GB2008/000876 2004-04-30 2008-03-13 Détecteur WO2008117016A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP08718718A EP2140435B1 (fr) 2007-03-27 2008-03-13 Détecteur
US12/568,423 US8198997B2 (en) 2004-04-30 2009-09-28 Fire gas detector-coding

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0705888.6 2007-03-27
GB0705888A GB2447917A (en) 2007-03-27 2007-03-27 Using resistors in a fire detector to indicate the life span or manufacturing date of each sensor

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
US11/587,461 Continuation-In-Part US7609154B2 (en) 2004-04-30 2005-04-29 Testing a fire detector sensor
PCT/GB2005/001641 Continuation-In-Part WO2005106822A1 (fr) 2004-04-30 2005-04-29 Essai d'un capteur de detecteur d'incendie

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US12/568,423 Continuation US8198997B2 (en) 2004-04-30 2009-09-28 Fire gas detector-coding

Publications (1)

Publication Number Publication Date
WO2008117016A1 true WO2008117016A1 (fr) 2008-10-02

Family

ID=38024959

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2008/000876 WO2008117016A1 (fr) 2004-04-30 2008-03-13 Détecteur

Country Status (3)

Country Link
EP (1) EP2140435B1 (fr)
GB (1) GB2447917A (fr)
WO (1) WO2008117016A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2437225A1 (fr) 2010-10-01 2012-04-04 Siemens Aktiengesellschaft Réglage du mode de fonctionnement d'un dispositif d'alerte aux dangers à l'aide d'un dipôle, notamment une résistance, électriquement lisible et agencé dans un socle d'alerte aux dangers

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2844084A1 (fr) * 2002-08-30 2004-03-05 Finsecur Sa Telecommande pour capteur ou actionneur electronique
US20040217857A1 (en) * 2003-04-30 2004-11-04 Gary Lennartz Smoke detector with performance reporting
WO2005106822A1 (fr) * 2004-04-30 2005-11-10 Thorn Security Limited Essai d'un capteur de detecteur d'incendie

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5754027A (en) * 1996-07-08 1998-05-19 Motorola, Inc. Battery pack and associated charging system
DE19722744A1 (de) * 1997-05-30 1998-12-03 Draegerwerk Ag Detektionssystem mit austauschbaren Sensoren
US6316916B2 (en) * 1999-12-17 2001-11-13 Motorola, Inc. Method and mechanism to prevent corruption of data
US6533926B2 (en) * 2001-04-05 2003-03-18 Fleetguard, Inc. Filter cartridge with concentric circuit rings for data transmission
JP2004239871A (ja) * 2003-02-10 2004-08-26 Hakko Automation Kk 多点環境監視装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2844084A1 (fr) * 2002-08-30 2004-03-05 Finsecur Sa Telecommande pour capteur ou actionneur electronique
US20040217857A1 (en) * 2003-04-30 2004-11-04 Gary Lennartz Smoke detector with performance reporting
WO2005106822A1 (fr) * 2004-04-30 2005-11-10 Thorn Security Limited Essai d'un capteur de detecteur d'incendie

Also Published As

Publication number Publication date
EP2140435A1 (fr) 2010-01-06
GB0705888D0 (en) 2007-05-02
GB2447917A (en) 2008-10-01
EP2140435B1 (fr) 2012-10-24

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