GB750036A - Improvements in or relating to automatic thermal alarm systems - Google Patents
Improvements in or relating to automatic thermal alarm systemsInfo
- 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
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
Landscapes
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fire-Detection Mechanisms (AREA)
- Fire Alarms (AREA)
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.
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)
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)
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)
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 |
-
0
- NL NL94775D patent/NL94775C/xx active
- FR FR1093208D patent/FR1093208A/fr not_active Expired
-
1954
- 1954-02-12 DE DET9027A patent/DE1005877B/en active Pending
- 1954-02-12 GB GB4263/54A patent/GB750036A/en not_active Expired
- 1954-02-13 CH CH322839D patent/CH322839A/en unknown
Cited By (5)
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 |
---|---|
CH322839A (en) | 1957-06-30 |
NL94775C (en) | |
DE1005877B (en) | 1957-04-04 |
FR1093208A (en) | 1955-05-02 |
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