GB750036A - Improvements in or relating to automatic thermal alarm systems - Google Patents

Improvements in or relating to automatic thermal alarm systems

Info

Publication number
GB750036A
GB750036A GB4263/54A GB426354A GB750036A GB 750036 A GB750036 A GB 750036A GB 4263/54 A GB4263/54 A GB 4263/54A GB 426354 A GB426354 A GB 426354A GB 750036 A GB750036 A GB 750036A
Authority
GB
United Kingdom
Prior art keywords
resistors
temperature
tube
circuit
discharge
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
Application number
GB4263/54A
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.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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 Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of GB750036A publication Critical patent/GB750036A/en
Expired legal-status Critical Current

Links

Classifications

    • 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

Abstract

750,036. Temperature alarms. TELEFONAKTIEBOLAGET L. M. ERICSSON. Feb. 12, 1954 [Feb. 14, 1953], No. 4263/54. Class 118(1) [Also in Groups XL(a) and XL(c)] A temperature-alarm circuit comprises two resistors, of which one at least is temperature-sensitive, joined in series and a gas-discharge-tube circuit connected in parallel with the resistors, the junction of the two resistors being connected to a point in the discharge tube circuit such that when the potential drop across one of the two resistors increases above a predetermined value a discharge occurs in the discharge-tube circuit whereby an alarm is actuated. Fig. 1 shows an arrangement comprising a plurality of temperaturesensitive circuits P1, P2 &c. connected in parallel across a pair of lines L1, L2 and connected in series with an alarm unit C. The circuits P1, P2 &c. each comprise two similarly-temperature-sensitive resistors T1, T2 and a cold-cathode discharge tube G, one of the resistors being heat-insulated as indicated by the rectangle H. The junction point of the resistors T1, T2 is connected to the control electrode of the discharge tube G so that, when the temperature rises suddenly, the resistance of T2 decreases more rapidly than that of T1, and the tube is fired due to the increase in potential at the junction point of the two resistors. The current flowing in the tube G operates the relay R to close the circuit of the alarm S1. Fig. 2 shows an alternative arrangement, wherein the coldcathode tube G is replaced by two series gas-filled diodes, the junction point of the two resistors being connected to the junction point of the two diodes. The circuit may also be modified by the replacement of one of the temperature-sensitive resistors by one not varying with temperature or one having a different temperature coefficient of variation, in which cases the heat insulation may be omitted. The resistance elements may be formed directly on the envelope of the cold-cathode triode shown in Fig. 1.
GB4263/54A 1953-02-14 1954-02-12 Improvements in or relating to automatic thermal alarm systems Expired GB750036A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE322839X 1953-02-14

Publications (1)

Publication Number Publication Date
GB750036A true GB750036A (en) 1956-06-06

Family

ID=20307884

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4263/54A Expired GB750036A (en) 1953-02-14 1954-02-12 Improvements in or relating to automatic thermal alarm systems

Country Status (5)

Country Link
CH (1) CH322839A (en)
DE (1) DE1005877B (en)
FR (1) FR1093208A (en)
GB (1) GB750036A (en)
NL (1) NL94775C (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3245067A (en) * 1963-05-24 1966-04-05 B R K Electronics Inc Detection of products of combustion
GB2215502A (en) * 1988-02-02 1989-09-20 Nittan Co Ltd A fire detector having a protective cover
WO2011006478A3 (en) * 2009-07-14 2011-05-26 Petra Hess Electrical circuit for monitoring temperatures

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1101229B (en) * 1956-11-12 1961-03-02 Reich Robert W Electric fire alarm
NL224947A (en) * 1957-02-19
DE1234588B (en) * 1958-06-21 1967-02-16 Frans C Lemaire Circuit arrangement for determining the rate of increase in the temperature of a location

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR906870A (en) * 1944-08-31 1946-02-22 Cie Francaise Du Signum Improvements in electrical fire signaling devices and the like
BE459861A (en) * 1945-03-02
US2619595A (en) * 1947-10-24 1952-11-25 Honeywell Regulator Co Flame detection apparatus
GB637207A (en) * 1947-12-09 1950-05-17 Trist & Co Ltd Ronald Improvements relating to alarm or indicating systems employing photoeletcric cells

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3245067A (en) * 1963-05-24 1966-04-05 B R K Electronics Inc Detection of products of combustion
GB2215502A (en) * 1988-02-02 1989-09-20 Nittan Co Ltd A fire detector having a protective cover
US4929093A (en) * 1988-02-02 1990-05-29 Nittan Company Fire detector having a protective cover
GB2215502B (en) * 1988-02-02 1992-10-21 Nittan Co Ltd A fire detector having a protective cover
WO2011006478A3 (en) * 2009-07-14 2011-05-26 Petra Hess Electrical circuit for monitoring temperatures

Also Published As

Publication number Publication date
FR1093208A (en) 1955-05-02
NL94775C (en)
DE1005877B (en) 1957-04-04
CH322839A (en) 1957-06-30

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