Abstract: Valves for controlling the release of a substance, include a housing having an inlet for connection to a source of the substance, an outlet, and a passage extending therebetween. The passage is enclosed by a ceramic disc and means are provided to apply an electrical pulse to the disc to break the disc and so connect the inlet to the outlet. The methods include containing the substance in a container, connecting the container to a valve; and applying an electrical pulse to the disc to break the disc and connect the inlet to the outlet. The valves and methods are particularly suited, but not limited, to the control of substances such as pressurised fire extinguishing media.

Abstract: A fire or explosion suppression system comprises a source (30) of a liquid suppressant under pressure, and a source (32) of an inert gas under pressure. The liquid suppressant is a chemical substance having a low environmental impact, with a short atmospheric lifetime of less than 30 days. The inert gas may be nitrogen, carbon dioxide, argon, neon or helium or mixtures of any two or more of them. The suppressant and the inert gas are fed under pressure to an output unit (34) comprising a mixing chamber in which the liquid and the gas impinge to produce a mist of the liquid suppressant of very small droplet size which is entrained in the pressurised gas together with vapour from the liquid, the so-entrained mist and vapour and the gas being discharged by a nozzle (44) into an area to be protected. The mist and vapour are therefore carried by the entraining and transporting high pressure gas into regions of the areas to be protected, enabling a total flooding capability.

Abstract: A fire extinguisher (10) has a discharge member (12) for directing an extinguishing agent from the extinguisher (10) towards a target. The extinguisher (10) also has at least one light beam director (17, 18) for directing a beam of light (19, 20) in a predetermined direction relative to the discharge member (12) so that the discharge member (12) can be aimed at a target by directing the light beam (19, 20) at or adjacent to the target.

Abstract: A temperature switch comprises a material (14) which melts and concomitantly undergoes a change in an electrical characteristic at a predetermined temperature. The temperature switch also includes at least two electrical contacts (10, 12) for detecting the change in the electrical characteristic. The material (14) comprises an organic cation and an anion and is preferably an ionic liquid.

Abstract: A system for discharging inert gas for extinguishing or suppressing a fire is disclosed. A fluid discharge control arrangement is positioned in a fluid flow path between a pressurised gas supply 10A,10B,10C and the target fire suppression zone 20. The fluid discharge control arrangement reduces the pressure in the fluid flow path downstream thereof. This may allow the downstream pipework to be selected to withstand a lower pressure than in a conventional system in which the fluid discharge control device was not provided, thereby reducing costs. The fluid discharge control device may comprise a first valve 30 and first restrictor 26 in the first flow path 22 and a second valve 32 and a second restrictor 28 provided in the second flow path 24. Fluid from the containers 10A,10B,10C flows initially through flow path 24 and restrictor 26. Subsequently flow path 22 may be closed by optional valve 30, and flow path 24 is opened by valve 32. Fluid flow then passes through restrictor 28.

Abstract: A fire or explosion suppression system comprises a source (30) of a liquid suppressant under pressure, and a source (32) of an inert gas under pressure. The liquid suppressant is a chemical substance having a low environmental impact, with a short atmospheric lifetime of less than 30 days. The inert gas may be nitrogen, carbon dioxide, argon, neon or helium or mixtures of any two or more of them. The suppressant and the inert gas are fed under pressure to an output unit (34) comprising a mixing chamber in which the liquid and the gas impinge to produce a mist of the liquid suppressant of very small droplet size which is entrained in the pressurised gas together with vapour from the liquid, the so-entrained mist and vapour and the gas being discharged by a nozzle (44) into an area to be protected. The mist and vapour are therefore carried by the entraining and transporting high pressure gas into regions of the areas to be protected, enabling a total flooding capability.

Abstract: A smoke detector is shown in which blue light is directed through a scattering volume (9) from a radiation emitter (3) and infra-red radiation is also directed through the scattering volume (9) from an infra-red source (3A). Radiation forward-scattered by any particles in the scattering volume (9) is directed by a mirror (13) onto a photodiode (15) which produces an output to control means (16). The emitters (3,3A) are pulsed at different frequencies, enabling the control means (16) to produce separate signals (21,23) corresponding respectively to the scattered blue light and the scattered infra-red radiation. For smoke particles, significantly more blue light is scattered than infra-red radiation, but this is not so much the case for non-smoke particles. A comparator (25) takes the ratio of the two signals (21,23) to produce a smoke-dependent warning output.

Abstract: In order to allow a smoke detector unit to be utilised in, for example, a domestic kitchen environment, appliances whose operation is commonly associated with the generation of non-hazardous smoke or aerosols are connected to a conventional mains supply socket via a current monitoring unit. The current monitoring units include a radio transceiver, which transmits the operational status of the appliances to a corresponding transceiver of the smoke detector unit 1. If the signals transmitted by the current monitoring units indicate that the appliances and are off, the smoke detector unit generates a warning signal when the smoke density exceeds a lower threshold. If one of the appliances and is detected to be on, the smoke detector unit generates a warning signal only when a second, higher threshold of smoke density is exceeded. Optionally, when the higher smoke density threshold is exceeded; the smoke detector unit transmits the signal to the current monitoring unit to power off the appliances.

Abstract: In use of a UV gas discharge tube (such as used in flame monitoring apparatus), an electric field is periodically applied in the tube, each application of the field being followed by an ‘off’ period in which the field is removed. During this process, the mean value of the statistical lag Ts is measured over a predetermined time duration (the statistical lag is the time lag after each application of the electric field to the tube before conduction (if any) takes place). If the statistical lag lies within region I, the flame is judged to be present. If the statistical lag lies in region II, the flame is judged to be off (and a warning may be signalled). If the statistical lag lies in region III, a fault in the tube is signalled. This may be a “field emission” fault whereby free electrons are generated by the applied electric field, without the presence of UV radiation or it may be a “multiple counting” fault.

Abstract: Apparatus 11 for rapid discharge of one or more fire extinguishing agent(s) comprises a sealed container 13 forming an interior volume 15 in communication with a rapidly opening valve assembly 17. The interior volume contains fire extinguishing agent(s), super-pressurised by a gas such as nitrogen. A portion of the nitrogen is dissolved into the fire extinguishing agent(s). When an incident is detected which requires the discharge of the fire extinguishing agent(s) the valve 17 is opened. Opening the valve 17 causes rapid dissolution of the nitrogen from the fire extinguishing agent(s), forming a two-phase mixture (like a foam or mousse) which substantially fills the volume 15 and causing the discharge of fire extinguishing agent(s) from the valve assembly 17.

Abstract: Valves 1 and methods for controlling the release of a substance, the valves 1 comprising a housing having an inlet 3 for connection to a source of the substance, an outlet 5 and a passage 7 extending therebetween, the passage 7 enclosed by a ceramic disc 9 and means being provided to apply an electrical pulse to the disc to break the disc 9 and so connect the inlet 3 to the outlet 5, and the methods comprising the steps of containing the substance in a container, connecting the container to a valve 1 comprising a housing having an inlet 3 for connection to the source of the substance, an outlet 5 and a passage 7 extending therebetween, the passage 7 being closed by a ceramic disc 9, and applying an electrical pulse to the disc 9 to break the disc 9 and connect the inlet 3 to the outlet 5. The valves and methods are particularly suited, but not limited, to the control of substances such as pressurised fire extinguishing media.

Abstract: A smoke detector (1) has a spherical chamber (2) including a plurality of holes (15,17) for allowing smoke and other particles to enter the chamber. The majority of the internal surface (3) of the chamber (2) is covered with a high reflectivity Lambertian surface, that is a material that scatters incident light equally in all directions and at all wavelengths. The remaining portion of the internal surface (3) is coated with a light absorbing material (13) such as a matt black coating. A scatter sensor (9) is directed towards the absorbing coating (3), and an integrating detector (5) is configured to detect radiation directly from the entire Lambertian surface. A first LED (19) emits blue light into the chamber (2), and a second LED (21) emits infrared light into the chamber. Processing means (23, 25 and 27) are provided to analyse the signals from the detectors (5,9), including means for discriminating between signals from the sensors indicative of different frequencies of received radiation.

Abstract: A fire and explosion suppression system comprises a source (5) of high pressure water which is fed to a misting nozzle (13) at one input of a mixing unit (6), and a source (14) of high pressure inert gas, such as nitrogen, which is fed along a pipe (20) to another input of the mixing unit (6). Inside the mixing unit (6), water mist, in the form of an atomised mist of very small droplet size is mixed with the pressurised gas and exits the mixing unit (6) at high pressure and high velocity along a pipe (22) and is thence discharged through spreaders (26, 28). The source (5) of the water is pressurised by a feed (30) from the source of pressurised inert gas. The mass flow rate of the water will therefore reduce as the pressure of the gas decays. This tends to maintain the ratio of the mass flow rate of the water to the mass flow rate of the gas constant. This is found to produce and maintain an advantageous distribution of droplet size in the discharged unit.

Abstract: A method and device for sensing spatial variations and/or temperature variations in the locality of a fibre optic cable 1 is disclosed, wherein a broadband light source 47 is used to shine incident light onto a series of fibre Bragg gratings contained within zones A, B and C. Each zone contains a plurality of fibre Bragg gratings, the plurality of fibre Bragg gratings in any one zone having a substantially identical grating period, and the fibre Bragg gratings in the respective zones having different grating periods. The reflected light from each fibre Bragg grating is returned back down the fibre optic cable 1 and redirected via a 2×1 coupler 51 to a wavelength detection system 53 and a personal computer 63. The combination of wavelength detection system 53 and personal computer 63 allow analysis of the reflected light patterns, as well as providing a user interface which enables detection of the occurrence of a spatial and/or a temperature variation.

Abstract: A method of calibrating a combined carbon monoxide and carbon dioxide detector, and a combined carbon monoxide and carbon dioxide detector comprising a carbon monoxide sensor, a carbon dioxide sensor, and a carbon monoxide and carbon dioxide gas generator are disclosed. The method of self-testing the carbon monoxide and carbon dioxide detector comprises the steps of controlling the carbon monoxide and carbon dioxide gas generator to generate a known quantity of carbon monoxide and carbon dioxide; monitoring the response of the carbon monoxide sensor to the known quantity of carbon monoxide; monitoring the response of the carbon dioxide sensor to the known quantity of carbon dioxide; and correcting the calibration of the carbon monoxide sensor and/or the carbon dioxide sensor when the response is outside of a predetermined range.

Abstract: A fire simulator comprises fuel distribution means under a grating through which fuel emanating from the fuel distribution means can rise in use to create flames extending above the grating, wherein the grating includes a plurality of grating elements that together define a walkable working surface for a fire-fighter using the simulator.

Abstract: A nozzle has a body with a central cavity from which a plurality of fire extinguishant fluid outlets extend. The outlets extend non-radially with respect to the central axis of the cavity, i.e. at least a portion of each outlet is inclined with respect to any plane parallel to and passing through the central axis of the cavity which intersects the portion of the outlet. The extinguishant from the non-radial outlets is thrown towards the walls of the chamber, along the paths. The jets of the fluid induce a rotational movement within the ambient fluid (for example, air) already present in the chamber, thus creating a vortex or rotational movement of the fluid within the chamber. In another embodiment, the vortex or rotational movement is generated by a nozzle assembly of generally cruciform configuration with three or more discharge tubes having outlets formed therein for discharging extinguishant in equi-angularly-spaced directions.