US2587762A - Fire alarm apparatus - Google Patents

Fire alarm apparatus Download PDF

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Publication number
US2587762A
US2587762A US60790A US6079048A US2587762A US 2587762 A US2587762 A US 2587762A US 60790 A US60790 A US 60790A US 6079048 A US6079048 A US 6079048A US 2587762 A US2587762 A US 2587762A
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US
United States
Prior art keywords
relay
coil
contacts
circuit
current
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.)
Expired - Lifetime
Application number
US60790A
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English (en)
Inventor
Michael P Reece
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.)
PYROBAN DEVELOPMENTS Ltd
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PYROBAN DEVELOPMENTS Ltd
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Publication date
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Publication of US2587762A publication Critical patent/US2587762A/en
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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
    • G08B17/06—Electric actuation of the alarm, e.g. using a thermally-operated switch

Definitions

  • a pair of resistor elements are connected in series with the coil of a polarized relay, a predetermined rate of temperature rise in the ambient temperature of the air upsetting the balance of the polarized relay to operate an alarm signal.
  • a further feature Vof the invention is the provision of a further coil in the main circuit capable of operating indicating mechanism for fault location.
  • Fig. l is a circuit diagram showing one embodiment of the invention.
  • Fig..2 is a circuit diagram showing a modified embodiment
  • Fig. 2a shows a modied detail modication of Fig. 2;
  • Fig. 3 is a side elevation, partly in section, at an enlarged scale of a detector head shown in Figs. l and 2;
  • Fig. 4 is a side elevation partly in section of same at right angles to Fig. 3; and e Fig. 5 is a plan of same. l
  • the apparatus4 comprises one or' more detector heads I connected in series where more than one is employed.
  • Each detector head I comprises two resistor elements a, d (see also Figs. 3 and 4) one element a being wound on a skeleton former 2 more fully to be described presently with adjacent turns separated so as to present a large surface area in relation to its weight.
  • the second element d is wound on the same former, with its varnished turns close together and overlapping so as to provide a small surface area in relation to its weight.
  • the former 2 comprises a base plate 3 having four fabric covered rods 4 around which the elements a and'd are wound.
  • ⁇ turns of the second element d may be lagged with other endY of the Spring@ .isarrisd by@ Pillar
  • a resistance strip c may be con- 'I mounted on the base plate 3.
  • the former 2 is suspended from a ceiling or in any other suitable position so that air may circulate freely around the elements.
  • the base plate and terminals are enclosed in a cover 8 carried by a spindle 9 secured to the former 2, the cover leaving a clearance space between the ceiling or other surface and the base of the cover so as to allow the circulation of air over the winding of the elementa.
  • the two elements a and d are connected in parallel across a D. C. supply 9
  • One end of each element a and d is connected in series with a coil e or coil f, respectively, of the polarized relay 5I, the two coils e and ,f of which are wound in opposition, the free ends of the coils e and f being connected by the potentiometer R1, the movable contact R of which is fed from one terminal of the D. C. supply 9
  • the D. C. supply may be obtained from la battery or through a rectiiier from A. C. mains.
  • the polarized relay 5I is adjusted by moving the contact R" and the potentiometer R1 so that at normal temperatures the currents passing through the coils e and f are equal and balance each other, and no resultant magnetism is available which could operate in the manner more fully described hereinafter a relay circuit 'II containing an alarm device such as a red lamp 6I vand/or an audible alarm bell or gong 8
  • the warning circuit is operated by a reed II suspended between the coils e and f, the free end lof the reed normally resting between two contacts h and g, the contact g being connected to the lead 6I' to the lamp 6I.
  • the reed II makes contact with the contact g if any current being out of balance should circulate in the coil f.
  • the relay circuit II comprises a coil I2 and two pairs of contacts I3 and I4. When the reed II makes Contact with the contact g the coil I2 is energised so as to close the contacts I3 and I4, the closing of the contacts I3 operating the alarm device 8
  • the second pair of contacts I4 a' re connected in a resetting circuit in series with a variable resistance R2 across the coil f and part of the potentiometer R1.
  • the closing of the contacts I 4' reduces the current flowing in the compensating winding f of the polarized relay 5I and causes the ,reed II to leave the contact g thereby resetting .the circuit.
  • An out of b alance current can' be caused also with a slow rise of temperature which acts substantially at the same rate on both windings a and d by firing the strip of low melting anchor ingbead 6 of the spring b so that the short-circuit 'of ⁇ the'strip c is removed and the windings a and d carry diierent currentsV thereby unbalancing Vthe circuit andcausing the operation of the alarm devices.
  • Fig. 2 The'arrangement shown in Fig. 2 is applicable for' industrial purposes such as for use in coal mines', on aircraft, or other applications.
  • the main circuit is similar to that hereinbefore described, but includes a fault relay I5.
  • the potentiometer R1 may be replaced by a potentiometer R3 in series with the coil f (Fig. 2a) and has a tapping point in series with the relay I5 which providesv a somewhat finer adjustment.
  • the coil of the relay I5 is of low resistance and the current normally iiowing in themain circuit is arranged so as to hold contacts IIiY closed. Should the current fall below a predetermined value therelay'contacts IE open and contactsv I1 close. The closing of contacts I1 illuminates-a lamp I3 which may be coloured amber'and indieating a circuit fault. Simultaneously ay relay coilIBis energised to close contacts and'sound a faultindicating buzzer 2l. Thus if any of the leads to the head I arey severedor'the heads I themselves are damaged the current owing in the main circuit will fall in value andthe fault ndingcircuit will give an indication thereof. A similar operation of the relay I9' occurs if the supply of current to the mainfcircuit drops. For use in mines plate rectiers vmay be arranged -in parallel with the coils so as to reduce sparking.
  • the opening of the contactsv I6 of the relay-I5 also vopens the circuitof the reed I IY of the polarized relay 5I thereby preventing a spurious operation of the fire alarm device.
  • each vunit is provided with a lamp IB' operated in parallel from a single relay I5 which'will cause the lamp in the faulty circuit to be illuminated and also operate the buzzer 2
  • V may be providedin order to prevent thecircuit from being; reset automatically so that the circuit' remaiIIsin'its 4 alarm condition until reset manually by operation of the switch 22I.
  • a test circuit may be incorporated by introducing a single pole two way switch 23 which normally completes the circuit between the rheostatfR'andpoint 24 butwhich;v when loperated connectsY the'- potentiometer B2i to a point 25 thereby putting the potentiometer R2 in shunt with the winding e thus reducing the current flowing-therein and simulating a disturbing condition at the heads I.
  • the detector. heads may be constructed on ceramic formersand' the elements a and d may consist of tungsten wirefsonasfto only operate when a predetermined'. temperature has been exceeded.
  • heads I are shown in series in the drawings but one or two or up to twelve or more may be employed.
  • a fire alarmy apparatus comprising in: combination a current source; ar detector head;A a
  • iirst resistor element and a second resistor element arranged. in saidvhead and each connected with-one end thereof to a terminalof saidcur-r rent source; a polarizedA relay having a. rst coil and asecond coil wound in opposition. to said first coil, said iirstu coil being connectedY in series with said first resistor element and said second coil being 4connectedin series with said second resistor element; a potentiometer con.- necting said rst.coil.,and said second coil with each other so as to provide a balancedcircuit at normal temperatures; a;A reed arranged between said coilsof' saidpolarized relay for de.- fiection out of f itsnormalposition. by any.
  • said reed, saidzrstipairof.contacts opening when vthe current through saidsecond-relay falls ,below apredetermined vaiue andrthusfinterrupting said secondary cirouit2.in .order' to. prevent a spurious opera-tionof; said.warning. device.; a second pair ofl contactspperatedby said second relay, said second pair of. contacts.. closing whenv the currentxfthrough said, second. relayfalls, below the predeterminedvalue; anda fault-indicating cevice connectedQto. said. second pair of contacts so .as .tobe operated bythe closing thereof simultaneously withthe opening of said first pair of contacts of said second relay.
  • viirst coil saidrst coil Abeing connected; in series with saidy first resistor-- element andsaid secassmec ond coil being connected in series with said second resistor element; a potentiometer connecting said rst coil and said second coil with each other so as to provide a balanced circuit at normal temperatures; a reed arranged between said coils of said polarized relay for deflection out of its normal position by any out-of-balance currents flowing in said polarized relay; a contact arranged at the free end of said reed so as to be closed when an out-of-balance current ows in said polarized relay; a secondary circuit energized by the closing of said contact of said reed; a first relay in said secondary circuit, said rst relay being energized when an out-of-balance current flows in said polarized relay; a pair of contacts operated by said relay so as to be closed upon the energization thereof; a warning device connected in series to said pair

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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)
  • Emergency Alarm Devices (AREA)
US60790A 1947-11-25 1948-11-18 Fire alarm apparatus Expired - Lifetime US2587762A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB31185/47A GB632279A (en) 1947-11-25 1947-11-25 Improvements in fire alarm apparatus

Publications (1)

Publication Number Publication Date
US2587762A true US2587762A (en) 1952-03-04

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Family Applications (1)

Application Number Title Priority Date Filing Date
US60790A Expired - Lifetime US2587762A (en) 1947-11-25 1948-11-18 Fire alarm apparatus

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US (1) US2587762A (en))
BE (1) BE488984A (en))
GB (1) GB632279A (en))

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2759174A (en) * 1952-08-26 1956-08-14 American District Telegraph Co Fire detector
US2827624A (en) * 1955-10-27 1958-03-18 Specialties Dev Corp Electrical network for detecting heat due to various causes
US3798971A (en) * 1971-11-01 1974-03-26 Lowrance Electronics Mfg Temperature differential sensor for gliders
US4521120A (en) * 1983-09-15 1985-06-04 The United States Of America As Represented By The Secretary Of Agriculture Forest fire rate of spread with timers method

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2667630A (en) * 1950-12-22 1954-01-26 Jorgensen Asger Lars Automatic fire alarm system
RU2330701C1 (ru) * 2006-12-20 2008-08-10 Общество с ограниченной ответственностью "Огнетек" Устройство сигнально-пусковое

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US245272A (en) * 1881-08-09 beight
US419710A (en) * 1890-01-21 Electric protective system
US1954832A (en) * 1930-02-11 1934-04-17 Vega Manuf Automatic starter
US2000074A (en) * 1928-03-08 1935-05-07 Kidde & Co Walter Supervised electric system
US2003443A (en) * 1931-06-09 1935-06-04 American Telephone & Telegraph Contactor indicator
US2003358A (en) * 1929-11-21 1935-06-04 Kidde & Co Walter System for indicating the presence and location of fire
US2219262A (en) * 1937-07-21 1940-10-22 Western Union Telegraph Co System for detecting and locating defects in cable sheaths
US2236891A (en) * 1937-07-17 1941-04-01 Gamewell Co Fire alarm system
US2302593A (en) * 1940-02-09 1942-11-17 Brown Instr Co Control apparatus
US2398892A (en) * 1943-07-08 1946-04-23 Edison Inc Thomas A Resistor bulb
US2412471A (en) * 1943-07-02 1946-12-10 Honeywell Regulator Co Air-speed responsive device
US2448575A (en) * 1942-06-18 1948-09-07 Brown Instr Co Electrical instrument follow-up system

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US245272A (en) * 1881-08-09 beight
US419710A (en) * 1890-01-21 Electric protective system
US2000074A (en) * 1928-03-08 1935-05-07 Kidde & Co Walter Supervised electric system
US2003358A (en) * 1929-11-21 1935-06-04 Kidde & Co Walter System for indicating the presence and location of fire
US1954832A (en) * 1930-02-11 1934-04-17 Vega Manuf Automatic starter
US2003443A (en) * 1931-06-09 1935-06-04 American Telephone & Telegraph Contactor indicator
US2236891A (en) * 1937-07-17 1941-04-01 Gamewell Co Fire alarm system
US2219262A (en) * 1937-07-21 1940-10-22 Western Union Telegraph Co System for detecting and locating defects in cable sheaths
US2302593A (en) * 1940-02-09 1942-11-17 Brown Instr Co Control apparatus
US2448575A (en) * 1942-06-18 1948-09-07 Brown Instr Co Electrical instrument follow-up system
US2412471A (en) * 1943-07-02 1946-12-10 Honeywell Regulator Co Air-speed responsive device
US2398892A (en) * 1943-07-08 1946-04-23 Edison Inc Thomas A Resistor bulb

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2759174A (en) * 1952-08-26 1956-08-14 American District Telegraph Co Fire detector
US2827624A (en) * 1955-10-27 1958-03-18 Specialties Dev Corp Electrical network for detecting heat due to various causes
US3798971A (en) * 1971-11-01 1974-03-26 Lowrance Electronics Mfg Temperature differential sensor for gliders
US4521120A (en) * 1983-09-15 1985-06-04 The United States Of America As Represented By The Secretary Of Agriculture Forest fire rate of spread with timers method

Also Published As

Publication number Publication date
BE488984A (en))
GB632279A (en) 1949-11-18

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