US3588892A - Test of parallel alarm units - Google Patents

Test of parallel alarm units Download PDF

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Publication number
US3588892A
US3588892A US784655A US3588892DA US3588892A US 3588892 A US3588892 A US 3588892A US 784655 A US784655 A US 784655A US 3588892D A US3588892D A US 3588892DA US 3588892 A US3588892 A US 3588892A
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United States
Prior art keywords
alarm
units
checking
alarm unit
alarm units
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Expired - Lifetime
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US784655A
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English (en)
Inventor
Andreas Scheidweiler
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Cerberus AG
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Cerberus AG
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING SYSTEMS, e.g. PERSONAL 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
    • G08B29/123—Checking intermittently signalling or alarm systems of line circuits
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING SYSTEMS, e.g. PERSONAL 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
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING SYSTEMS, e.g. PERSONAL 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

Definitions

  • the basic signal installation itself comprises a plurality ofindividual alarm units, each alarm unit [54] TEST OF PARALLEL ALARM UNITS being connected in parallel preferably across a pairof supply 7 Claims 3 Drawing Figs conductors leading to some central mon toring station.
  • Each alarm unit 15 preferably of the type wherein, at the occurrence 1 1 Cl 340/410, of an alarm condition, an electrical contact is closed therein 340/228 essentially shorting the supply conductors.
  • alarm conditions are electrically simulated at each [50] Field of Search 340/213, alarm unit.
  • each alarm unit responds to the checking 213.1, 214, 215, 227, 228, 228.1, 410, 411, 228.2, eration, and additional electrical contact associated with 408,409. 22 each alarm is closed.
  • the additional or checking electrical contacts are connected in a separate series circuit leading [56) References Cited back to the central monitoring station. If all alarms of the plu- UNITED STATES PATENTS rality of alarm units have properly responded to the checking 2,847,662 8/1958 Lindgren 340/227.1 operation, then the separate series circuit comprising all the 3,235,858 2/1966 Mader 4. 340/214 additional electrical contacts will be completed. Should one of 3,530,450 9/1970 Walthard et a1.
  • the present invention generally relates to alarm signal installations and particularly concerns an improved alarm signal installation of the type incorporating a plurality of parallel connected individual alarm units along with a device enabling the simultaneous remote triggering of each alarm unit for the purpose of checking the operational readiness of the same.
  • Alarm units in their basic structural format, generally comprise an electrical switch or contact which, upon the occurrence of a predetermined change in magnitude ofsome condition being monitored, alters its switching state. The change or alteration of the switching state generally triggers an indicating device at some remote, central location. If the basic alarm unit is of the type wherein its switching or electrical contact is normally open in the rest or unactuated condition of the associated alarm unit, then one would be concerned with the measurement of a working current in the entire alarm circuit to indicate the occurrence of an alarm condition.
  • Alarm units of this basic type can generally be connected either in series with one another or in parallel circuit relation within any given signal installation. Generally speaking, if the individual alarm units are all connected in series, then such alarm units must be of the type wherein their individual switching contacts are normally closed and wherein the signal installation draws some ambient current during an unactuated condition of the alarm units.
  • the type of signal installation referred to herein comprises a plurality of parallel connected alarm units having switching contacts which, upon the occurrence of an alarm or an alarmsimulating condition, close to effectively short the supply conductors
  • the checking technique proposed in the prior-art involves the comparison, at the central station, of the total current l, flowing through the alarm units during the checking operation with some reference value current I deviations of the total actual value of current from the reference value being considered as indicative of a disturbance.
  • alarm units as actually utilized today are generally not constructed with very close or high tolerances of their individual electrical characteristics.
  • the invention is generally manifested by the features that, in addition to the usual electrical switching contacts coupled in parallel across the supply conductors in a parallel alarm system installation, further electrical contacts are provided at each of the tire alarm units and are interconnected in their own series connected circuit.
  • the series connected additional electrical contacts operate in conjunction with the main or switching electrical contacts yet are coupled in series connection to the central or remote station or location with a voltage source and a separate current measuring device.
  • the current measuring device at the central location determines the flow of current through the series connection of additional contacts and, if no such current exits, a disturbance indicating device is triggered.
  • FIG. I is an electrical block diagram of a preferred embodiment ofthe inventive signal installation
  • FIG. 2 is a circuit diagram depicting, in simplified form, one embodiment ol'an individual alarm unit of the system.
  • HG. 2a depicts alternative elements for the circuit of FIG. 2.
  • inventive installation comprises a plurality of alarm units 1, l'...electrically connected to a central remote station 2.
  • alarm units 1 and l For illustrative convenience, however, only two such alarm units 1 and l have been indicated on FIG. 1 although it should be appreciated that any number of alarm units can be utilized.
  • Each such alarm units 1, l'... essentially embodies or comprises a signal transmitter 5, 5...responsive to the occurrence of some condition that is desired to be monitored.
  • the signal transmitters 5, 5'...could be responsive to the size of combustion particles in the air and thus to the occurrence of a fire.
  • Each alarm unit further is provided with an associated electronic circuit as well as a switch, supply as a relay 6, 6...respectively, actuated by the associated signal transmitter.
  • the relay 6 of alarm unit 1 is illustrated as comprising two work current or switching contacts 7 and 8 whereas the relay 6 of alarm unit I is illustrated as comprising a single work current or switching contact 7.
  • Contacts 7 and 7' are coupled to the supply conductors 3 and 4 in such a manner that, in the closed position of these contacts, supply conductors 3 and 4 are short-circuited.
  • a relay 37 having a work current contact 8' such as illustrated with respect to alarm unit 1' can be connected in series circuit with the switching contact 7 itself. In either case, energization of the relay 6 or 6' effects closing of the additional contacts 8 and 8', respectively.
  • the work current or additional contacts 8 and 3' of alarm units 1 and l as well as the additional contacts provided in a similar manner for each of the other alarm units connected in the installation are themselves coupled in series circuit with one another.
  • the additional contact 8 of alarm unit I from which the series circuit connection commences is advantageously coupled with one of the two supply conductors 3 and 4 and, in the case illustrated, contact 8 is coupled with supply conductor 3.
  • Each of the alarm units 1, l'...further comprises supply conductor inputs 10, l1; l, ll...and exchangeable input and output leads l3 and 14, 13', l4...leading to the respective work contacts 8, 8....
  • An additional control input 12, l2'... is provided for each alarm unit and such control input as well as its function will be discussed hereinbelow.
  • the central or remote station 2 which for illustrative clarity and convenience has been depicted in a simplified form, comprises a battery 15 having cells 15a and [b, a signal relay 16, a disturbance indicator relay l7, and a testing switch 18 having switch contacts 18a, 18b, and 180.
  • the series connection of the battery and the signal relay 16 is disposed between the clamps or connections 20 and 2! of the supply conductors 3 and 4.
  • Signal relay I6 is designed in such a fashion that the rest" current flowing through the fire alarm groups or units I, ll ...when the respective contacts 7, 7...are open does not switch the relay.
  • relay I6 Upon the occurrence and transmission of an alarm signal by one of the alarm units, in other words, upon closing of one of the "work" current contacts 7, 7'....signa
  • each alarm unit depicts each alarm unit as having a single control input l2, I2...which is connected to a common control conductor 9.
  • Control conductor 9 is connected via terminal 22 to the central station 2 and, via resistor 19, with the center tap of both cells l5a and lSb of the battery 15.
  • the control conductor 9 is switched via contact 18b to the input terminal or side of cell l5! of the battery.
  • the triggering of the alarm units for the purpose of checking the operational readiness of such units can take place in a variety of different manners utilizing different techniques.
  • One such technique known to the art utilizes supply conductors 3 and 4 to trigger the checking operation and thus do not require the provision of an additional control conductor 9. So as to suppress, during the operational readiness checking operation, the transmission of an actual alarm signal such as would occur, for example, upon triggering of a fire alarm, the signal relay 16 is shunted or bypassed via the action of contact [8a which places a small resistor 28 across the relay l6.
  • Disturbance relay [7 comprises a spe cialized form of a common current measuring device.
  • Disturbance relay 17 would then respond opening its associated switching contact in the auxiliary current circuit consisting of the terminal 25, a checking switch contact which is closed by action of switch 18, indicating lamp 29, and the terminal 26.
  • the auxiliary current circuit comprising the terminal 25, the closed checking switch contact 18c, illuminating lamp 29, and terminal 26 would remain in a closed, continuous loop path such that the disturbance indicating lamp 29 would illuminate.
  • FIG. 2 a preferred embodiment of an actual alarm unit utilized in the inventive signal installation is disclosed, the alarm unit itself generally being of known construction and being equipped with ionization chambers or compartments so as to operate as a fire alarm.
  • a measuring ionization chamber 30 is disposed in series circuit relation with a reference ionization chamber 31 across terminals 1] and 12 of the signal installation described with reference to FIG. I.
  • the midpoint between the ionization chambers 30 and 31 is coupled via a lead to an amplifier element having a high ohmic input, the amplifier element being illustrated here as comprising a field-effect transistor 32, the cathode of which is prebiased via a voltage divider resistor 33 and resistor 34, the anode of which is coupled to the base of a further transistor 36.
  • a resistor 35 is connected in parallel to the emitter-base path of transistor 36 whereas the emitter of transistor 36 is directly coupled to supply conductor II.
  • the collector of transistor 36 is coupled to the supply conductor I0 through a relay winding 37.
  • field-effect transistor 32 and therefore, transistor 36 begins to conduct.
  • the potential change necessary at the gate of field-effect transistor 32 as described may be brought about by a change in the ionization current flowing through the ionization chambers 30 and 3] due to the occurrence of a fire, or may alternatively be brought about due to a change of the voltage at the control terminal 12 such as would be the case during an operational-readiness checking procedure initiated at the central station 2.
  • transistor 36 when transistor 36 begins to conduct, a current flows between supply conductors and 11 through transistor 36 and the relay winding 37, this current flow triggering the alarm indicating device at the central station and simultaneously causing the closing of contact 8 depicted here as a gas-enclosed reed switch due to the interac tion between the reed switch and the relay coil 37. Accordingly, transistor 36 assumes the function of relay 6' and its associated work contact 7' such as described with respect to the overall installation of FIG. I. On the other hand, the additional work current contact 8 described with respect to the alarm unit 1' of FIG. I finds its counterpart in the actual alarm of FIG. 2 in the reed switch 8.
  • Relay coil 37 of the alarm unit depicted in FIG, 2 serves the same function as relay 37 of the signal installation in FIG. 1.
  • the additional switching element described herein as the relay 37 and the associated reed switch contact can be replaced by other suitable components.
  • a light source 40 instead of relay winding 37 could be utilized in conjunction with a photoelectric cell 42 instead of the mechanical reed switch contact ll.
  • a temperature-sensitive rexintor 44 could be utilized having a heating winding 46.
  • the alternative provision of a light source and a photoelectric cell is particularly advantageous if the alarm unit itself is previously equipped with some type of an individual-indicator lamp signifying a proper operation. If this indicator lamp is simultaneously used as the light source for the photoelectric cell, then, apart from the economies realized by this physical construction, proper operation of the indicator lamp is also simultaneously monitored.
  • a signal installation comprising a plurality of alarm units connected in parallel circuit relation across a pair of supply conductors with a central station, said alarm units each comprising a main switch element responsive to triggering of the associated alarm unit to shunt said supply conductors with a signal current circuit; means for the simultaneous remote triggering of the alarm units for checking the operational readiness of the same; each of said alarm units comprising additional work current switches normally closed in response to said remote triggering; circuit means connecting said additional work current switches of the individual alarm units in series circuit relation and to said central station, said circuit means comprising a voltage source and a current measuring means; said current measuring means, during the checking operation, monitoring the flow of a work current and, upon the absence of a current flow, triggering a disturbance indicator at said central station.
  • each of said reed switches have an associated relay winding, means coupling said relay winding for the reed switch of each individual alarm unit in series circuit with said main switch element of the associated alarm unit, whereby closing of said main switch element in response to triggering of the associated alarm unit effects closing ofsaid associated reed switch.

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  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Alarm Systems (AREA)
  • Fire Alarms (AREA)
US784655A 1967-12-29 1968-12-18 Test of parallel alarm units Expired - Lifetime US3588892A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1834067A CH463329A (de) 1967-12-29 1967-12-29 Signalanlage mit mehreren parallel geschalteten Meldeeinheiten

Publications (1)

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US3588892A true US3588892A (en) 1971-06-28

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US784655A Expired - Lifetime US3588892A (en) 1967-12-29 1968-12-18 Test of parallel alarm units

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US (1) US3588892A (da)
AT (1) AT285388B (da)
BE (1) BE726158A (da)
CH (1) CH463329A (da)
DE (1) DE1815206C3 (da)
DK (1) DK123736B (da)
FR (1) FR1599970A (da)
GB (1) GB1202760A (da)
NL (1) NL163885C (da)
SE (1) SE385516B (da)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753258A (en) * 1970-03-31 1973-08-14 Nittan Co Ltd Fire alarming system
US3983548A (en) * 1975-02-19 1976-09-28 Tufts Howard L Fire detection system
US4170770A (en) * 1976-10-08 1979-10-09 Tokyo Shibaura Electric Co., Ltd. Gas leak-detecting apparatus
US4254411A (en) * 1978-04-19 1981-03-03 Siemens Aktiengesellschaft Danger alarm system
US4263587A (en) * 1979-04-09 1981-04-21 International Telephone And Telegraph Corporation Liquid level control system
US4369435A (en) * 1979-07-27 1983-01-18 Hochiki Kabushiki Kaisha Fire detector and fire alarm system having circuitry to detect removal of one or more detectors at a signal station
US4456907A (en) * 1981-01-12 1984-06-26 Pyrotector, Inc. Ionization type smoke detector with test circuit
US4481502A (en) * 1982-03-26 1984-11-06 Dawson N Rick Central smoke alarm and annunciator
GB2309109A (en) * 1996-01-10 1997-07-16 William Alexander Heffron Abnormal condition detecting unit and a circuit comprising a plurality of such units
CN107450521A (zh) * 2017-08-23 2017-12-08 郑州朗鑫智能电子科技有限公司 一种智能家居用电气检测装置
CN114067525A (zh) * 2021-11-02 2022-02-18 广东恩固安全科技发展有限公司 一种用于钢缆式生命线系统的新型报警装置
CN114518522A (zh) * 2022-01-27 2022-05-20 浙江恒强科技股份有限公司 一种电控系统用霍尔芯片的报警检测装置

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1169166B (it) * 1983-02-15 1987-05-27 Gd Spa Sistema di controllo funzionale di circuiti in ingresso a un'unita' centrale di controllo e comando per macchine e/o dispositivi utilizzabili in linee di produzione e/o confezionamento di prodotti
IT1169167B (it) * 1983-02-15 1987-05-27 Gd Spa Sistema di controllo funzionale per trasduttori di uscita di un'unita' centrale di controllo e comando per macchine e/o dispositivi utilizzabili in linee di produzione e/o confezionamento di prodotti
DE9408898U1 (de) * 1994-05-31 1995-09-28 Zettler GmbH, 80469 München Gefahrenmelder
DE102016200913A1 (de) 2016-01-22 2017-07-27 Hekatron Vertriebs Gmbh Vorrichtung zur Leitungsüberwachung von Gefahrenmeldern und Feststellvorrichtungen
DE102016200914A1 (de) 2016-01-22 2017-07-27 Hekatron Vertriebs Gmbh Vorrichtung zur Leitungsüberwachung an einer Feststelleinrichtung von Brandschutztüren mit Rauchschaltern

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753258A (en) * 1970-03-31 1973-08-14 Nittan Co Ltd Fire alarming system
US3983548A (en) * 1975-02-19 1976-09-28 Tufts Howard L Fire detection system
US4170770A (en) * 1976-10-08 1979-10-09 Tokyo Shibaura Electric Co., Ltd. Gas leak-detecting apparatus
US4254411A (en) * 1978-04-19 1981-03-03 Siemens Aktiengesellschaft Danger alarm system
US4263587A (en) * 1979-04-09 1981-04-21 International Telephone And Telegraph Corporation Liquid level control system
US4369435A (en) * 1979-07-27 1983-01-18 Hochiki Kabushiki Kaisha Fire detector and fire alarm system having circuitry to detect removal of one or more detectors at a signal station
US4456907A (en) * 1981-01-12 1984-06-26 Pyrotector, Inc. Ionization type smoke detector with test circuit
US4481502A (en) * 1982-03-26 1984-11-06 Dawson N Rick Central smoke alarm and annunciator
GB2309109A (en) * 1996-01-10 1997-07-16 William Alexander Heffron Abnormal condition detecting unit and a circuit comprising a plurality of such units
GB2309109B (en) * 1996-01-10 1999-08-04 William Alexander Heffron A detecting unit and a detecting circuit comprising a plurality of the detecting units
CN107450521A (zh) * 2017-08-23 2017-12-08 郑州朗鑫智能电子科技有限公司 一种智能家居用电气检测装置
CN114067525A (zh) * 2021-11-02 2022-02-18 广东恩固安全科技发展有限公司 一种用于钢缆式生命线系统的新型报警装置
CN114518522A (zh) * 2022-01-27 2022-05-20 浙江恒强科技股份有限公司 一种电控系统用霍尔芯片的报警检测装置

Also Published As

Publication number Publication date
CH463329A (de) 1968-09-30
GB1202760A (en) 1970-08-19
NL163885B (nl) 1980-05-16
NL6818361A (da) 1969-07-01
DE1815206A1 (de) 1969-07-10
SE385516B (sv) 1976-07-05
AT285388B (de) 1970-10-27
DE1815206C3 (de) 1975-08-07
DK123736B (da) 1972-07-24
DE1815206B2 (de) 1974-12-05
BE726158A (da) 1969-05-29
FR1599970A (da) 1970-07-20
NL163885C (nl) 1980-10-15

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