Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08B—SIGNALLING OR 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 present invention relates to compositions for controlling the operation of fire detection installations.
• the smoke, heat and combustible gas detectors are of several very diverse types as a principle.
• Ionization smoke detectors the operation of which is related to changes in the electrical conductivity of air in the presence of fire aerosols, react to the effect of combustion products in the form of visible fire aerosols or invisible.
• an electric field is established between two electrodes by means of direct voltage.
• the air between the electrodes is ionized, for example by means of a radioactive source, the resulting ions move under the effect of the field in the direction of the inversely charged electrode.
• fire aerosols enter the space between the two electrodes, part of the ions are deposited on the particles of these aerosols, until they are a thousand times heavier. The heavy ions thus obtained hardly move anymore due to mass inertia and therefore no longer contribute to the transport of charges and the current decreases.
• Combustible gas detectors consist of a semiconductor gas sensor selectively sensitive to certain combustible gases such as methane, propane and hydrogen.
• the highly sensitive optoelectronic system consisting of a specially developed semiconductor diode as an infrared light source, a silicon cell as a light receiver, a light absorber and protection against light from other sources, works on the principle of light scattering.
• the diode optics emit pulses of light in the form of a hollow cone. As long as the measurement chamber contains no smoke, the infrared light does not reach the receiver arranged in the center of the axis of the light cone. Upon entering the labyrinth chamber, the smoke particles scatter the light rays in all directions. Part of the scattered light reaches the photoelectric receiver which then produces an electrical signal.
• ionization smoke detectors products are used which have the property of stopping the ions created in the air by the radioactive source, in particular the formation of sufficiently heavy particles, and of capturing radiation from radioactive sources. Mention may be made of chloro-fluorinated, fluorinated organic products and gases such as nitrous oxide and carbon dioxide.
• the combustible gas detectors respond selectively according to the nature of the hydrocarbon; on the other hand, they are all more sensitive to other products such as alcohols, ethers, aldehydes, ketones and, in general, to many volatile organic compounds.
• an aerosol of fine droplets of liquid is sent, of products with a low vapor pressure less than 0.1 millibar, and preferably less than 0.01 millibar, dissolved in a large quantity of solvent with high vapor pressure.
• a liquid is sent which by vaporizing cools the atmosphere of the chamber enough to transform the water vapor of the air into ice crystals.
• compositions have been found to verify the operation of various types of smoke and combustible gas detectors. These compositions in the form of homogeneous mixtures of active products with respect to the three main types of detectors currently used, have the advantage of being more versatile than existing mixtures which are only active with respect to a single type of deto - guardian.
• the active products are introduced in proportions such that there is - whatever the type of detector - a low consumption of the composition of the mixture to be each test, from 0.5 to 2 grams, corresponding to injection times of 1 to 2 seconds; very short detector response time, maximum 10 seconds; and a very short remanence time of less than 10 seconds.
• the remanence time is the time during which the detector remains in alarm after injection.
• the mixture of active products also satisfies the following requirements: no risk of toxicity or corrosion, no formation of solid residues at very low vapor pressure which would foul the detectors.
• packaging in an aerosol can is easy and this mixture corresponds to aerosol standards, and is not subject to any specific labeling relating to toxic and flammable mixtures.
• the mixtures developed in the form of an aerosol to verify the operation of all types of smoke, optical or ionization detectors and combustible gases consist of at least one halogenoalkane in an amount greater than 75% by weight, at least one volatile organic compound with simple oxygen function of the alcohol type, oxo derivative, etheroxide in an amount less than 15% by weight, an organic product with low vapor pressure, less than 0.1 millibar, in very small amount at most a few percent weight.
• a propellant gas very soluble in these liquids is introduced into the mixture, such as nitrous oxide or carbon dioxide.
• haloalkanes can be chosen from chlorofluoro, chloro or fluoroalkanes, such as trichlorotrifluoroethane. Each mixture may contain one or more haloalkanes.
• the volatile organic compounds in particular the compounds with a simple oxygen function, such as alcohols, in particular acyclic alcohols, oxo derivatives, etheroxides, and among alkyl oxides, ethyl ether has proved particularly advantageous.
• alkyl phthalates are satisfactorily suitable as organic products with low vapor pressure, mention may be made of ethyl phthalate and butyl phthalate.
• compositions containing from 80 to 95% by weight of trichlorotrifluoroethane, approximately 1 to 10% by weight of ethyl ether and between approximately 0.05 and 1% by weight of alkyl phthalate and the complement to 100 with protoxide nitrogen have proven to be very satisfactory control products in fire detection; in particular, the compositions containing 90 to 95% by weight of trichlorotrifluoro ethane, preferably between 92 and 92.5%, and approximately 1% of ethyl ether, between 0.05 and 0.10% of ethyl or butyl phthalate and the complement to 100 in nitrous oxide.
• Flammability 10% of product with flash point below 100 ° C; flammability of the zero dispersion; toxicity: none.
• Flammability 10% of product with flash point below 100 ° 0; flammability of the zero dispersion; Toxicity: none, fog / smoke appearance, wetting at 10cm, non-wetting at 20cm.
• Flammability 10% of product with flash point below 100 ° C; flammability of the zero dispersion; toxicity: none, fog / smoke appearance, wetting at 10cm, non-wetting at 15cm.

Landscapes

• Engineering & Computer Science (AREA)
• Computer Security & Cryptography (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Fire-Detection Mechanisms (AREA)
• Fire-Extinguishing Compositions (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
• Sampling And Sample Adjustment (AREA)
• Fire Alarms (AREA)

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• 1984
  • 1984-10-30 FR FR8416562A patent/FR2572293B1/fr not_active Expired
• 1985
  • 1985-10-23 DE DE8585402056T patent/DE3576592D1/de not_active Expired - Lifetime
  • 1985-10-23 EP EP85402056A patent/EP0187053B1/de not_active Expired - Lifetime
  • 1985-10-23 AT AT85402056T patent/ATE51097T1/de active
  • 1985-10-29 CA CA000494072A patent/CA1246849A/fr not_active Expired
  • 1985-10-30 US US06/793,085 patent/US4715985A/en not_active Expired - Lifetime

Patent Citations (2)

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