GB1329475A - Ionization fire alarm - Google Patents
Ionization fire alarmInfo
- Publication number
- GB1329475A GB1329475A GB1528571*[A GB1528571A GB1329475A GB 1329475 A GB1329475 A GB 1329475A GB 1528571 A GB1528571 A GB 1528571A GB 1329475 A GB1329475 A GB 1329475A
- Authority
- GB
- United Kingdom
- Prior art keywords
- chamber
- alarm
- ionization
- fire
- dust accumulation
- 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
- G08B17/10—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
- G08B17/11—Actuation by presence of smoke or gases, e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means using an ionisation chamber for detecting smoke or gas
Landscapes
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Fire-Detection Mechanisms (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
1329475 Ionization fire detectors PREUSSAG AG FELIERSCHUTZ 17 May 1971 [ 16 May 1970 30 April 1971] 15285/71 Heading GIN In an ionization fire detector including a radioactive source the source has an activity less than 0À1 microcuries so that both free ions from smokeless fires which cause an increase in ionization current and smoke colloidal particles which cause decrease in ionization current can be detected. In the arrangement of Fig. 2 the junction of measuring chamber 1 and reference chamber 2 including radioactive sources 30, 31 is connected to output terminals 11, 12 via F.E.T. amplifiers 44, 43, dividers 5, 6 and 7, 8 being adjusted so that there is a voltage at 12 but not at 11. In the case of a smokeless fire the ionization current in chamber 1 is increased and the voltage at 12 becomes zero to operate an alarm. If smoke colloidal particles enter chamber 1 the ionization current decreases and the voltage at 11 increases to operate an alarm. Terminal 11 may be omitted and dividers 5, 6 adjusted so that both an increase or decrease in ionization current can be indicated at 12, Fig. 1 (not shown). The junction of the chambers 1, 2 may be connected to one input of an F.E.T. differential amplifier Fig. 4 (not shown). To produce a fire alarm signal only when the rate of charge of ionization current in chamber 1 exceeds a threshold level i.e. prevent the alarm being triggered due to DUST ACCUMULATION in the chamber the output of a F.E.T. connected to the chamber 1 is connected to a threshold amplifer via a differentiating amplifier. Alternatively or in addition an operational amplifier having a predetermined threshold may be used to actuate an alarm when the DUST ACCUMULATION exceeds a predetermined level, Figs. 5, 6, 7, 8 (not shown). DUST ACCUMULATION may also be detected by monitoring the activity of the radio-active source by means of a radiation detector and using the output of the detector to activate an alarm when the activity falls below a predetermined level, Fig. 9 (not shown) or to vary the conductivity of a transistor in series with the measuring chamber in place of the reference chamber 2 to nullify the effects of dust accumulation Instead of using a radiation detector DUST ACCUMULATION may be detected by insulating the radio-active source from the outer electrode so that a leakage current flows across the insulation when dust accumulates thereon which current may be used to operate an alarm or mitigate the effect of the dust Figs. 11, 12 (not shown). In Fig.13 (not shown) an auxiliary annular inner electrode is provided so that in the quiescent state these two electrodes are at equal potential and the ionization currents are equal. A fire alarm signal is only produced if there is a difference between the two currents.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE2024116 | 1970-05-16 | ||
DE19712121382 DE2121382A1 (en) | 1971-04-30 | 1971-04-30 | Iomsations fire alarm |
Publications (1)
Publication Number | Publication Date |
---|---|
GB1329475A true GB1329475A (en) | 1973-09-12 |
Family
ID=25759156
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1528571*[A Expired GB1329475A (en) | 1970-05-16 | 1971-05-17 | Ionization fire alarm |
Country Status (9)
Country | Link |
---|---|
US (1) | US3795904A (en) |
AR (1) | AR199378A1 (en) |
BE (1) | BE767246A (en) |
CA (1) | CA948332A (en) |
CH (1) | CH539310A (en) |
ES (1) | ES197895Y (en) |
FR (1) | FR2090086B1 (en) |
GB (1) | GB1329475A (en) |
NO (1) | NO129270B (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3906474A (en) * | 1973-05-07 | 1975-09-16 | Fire Alert Company | Combustion products alarm |
FR2402256A1 (en) * | 1977-08-29 | 1979-03-30 | Debard Robert | Fire detector and alarm system - has two radioactive ionisation chambers connected to resistances to form wheatstone bridge |
US4208655A (en) * | 1978-02-21 | 1980-06-17 | Westinghouse Electric Corp. | Protective system for electrical apparatus |
USRE30620E (en) * | 1978-07-03 | 1981-05-19 | P. R. Mallory & Co. Inc. | High output smoke and heat detector alarm system utilizing a piezoelectric transducer and a voltage doubling means |
ZA786519B (en) * | 1978-11-20 | 1980-02-27 | Anglo Amer Corp South Africa | Detector |
US4383253A (en) * | 1979-01-29 | 1983-05-10 | International Quartz Ltd. | Ionization smoke detector |
US4270123A (en) * | 1979-02-26 | 1981-05-26 | Universal Det, S.A.R.L. | Detector for indicating a fire or detector malfunction |
DE3004753C2 (en) * | 1980-02-08 | 1983-12-22 | Hartwig Dipl.-Ing. 2409 Scharbeutz Beyersdorf | Fire alarm device |
US5189399A (en) * | 1989-02-18 | 1993-02-23 | Hartwig Beyersdorf | Method of operating an ionization smoke alarm and ionization smoke alarm |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2950387A (en) * | 1957-08-16 | 1960-08-23 | Bell & Howell Co | Gas analysis |
NL224264A (en) * | 1957-10-24 | |||
LU48167A1 (en) * | 1965-03-11 | 1966-09-12 | Applic Electroniques Ets | |
FR1494089A (en) * | 1965-03-11 | 1967-09-08 | Pour Applic Electroniques Ets | Circuit for detecting and measuring signals, in particular signals derived from the ionization of a medium, particularly a gaseous medium |
CH446131A (en) * | 1966-02-22 | 1967-10-31 | Cerberus Ag | Ionization fire alarm system |
CH497755A (en) * | 1969-06-24 | 1970-10-15 | Cerberus Ag | Ionization fire alarms |
-
1971
- 1971-05-12 NO NO01806/71A patent/NO129270B/no unknown
- 1971-05-13 US US00142892A patent/US3795904A/en not_active Expired - Lifetime
- 1971-05-14 ES ES1971197895U patent/ES197895Y/en not_active Expired
- 1971-05-14 CA CA113,051A patent/CA948332A/en not_active Expired
- 1971-05-14 CH CH717471A patent/CH539310A/en not_active IP Right Cessation
- 1971-05-14 FR FR7117530A patent/FR2090086B1/fr not_active Expired
- 1971-05-17 BE BE767246A patent/BE767246A/en unknown
- 1971-05-17 GB GB1528571*[A patent/GB1329475A/en not_active Expired
- 1971-05-17 AR AR235587A patent/AR199378A1/en active
Also Published As
Publication number | Publication date |
---|---|
US3795904A (en) | 1974-03-05 |
CA948332A (en) | 1974-05-28 |
FR2090086B1 (en) | 1975-01-17 |
AR199378A1 (en) | 1974-08-30 |
BE767246A (en) | 1971-11-17 |
ES197895Y (en) | 1975-10-01 |
ES197895U (en) | 1975-05-01 |
FR2090086A1 (en) | 1972-01-14 |
CH539310A (en) | 1973-07-15 |
NO129270B (en) | 1974-03-18 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
414F | Notice of opposition given (sect. 14/1949) | ||
414A | Case decided by the comptroller ** specification amended (sect. 14/1949) | ||
SPA | Amended specification published | ||
PS | Patent sealed [section 19, patents act 1949] | ||
PCNP | Patent ceased through non-payment of renewal fee |