Abstract: A fire suppression system includes at least one high pressure gas source containing an inert gas, at least one low pressure gas source containing an organic halide gas, a distribution network connected with the high pressure gas source and the low pressure gas source to distribute the inert gas and the organic halide gas, and a controller in communication with the distribution network. The distribution network includes flow control devices configured to control flow of the inert gas and the organic halide gas. The controller is configured to initially release the inert gas in response to a fire threat to reduce an oxygen concentration at the fire threat below a preset oxygen concentration threshold, and release the organic halide gas to increase an organic halide gas concentration at the fire threat above a preset organic halide gas concentration threshold while the oxygen concentration is below the preset oxygen concentration threshold.

Abstract: A fire suppression system for an aircraft (cargo) compartment comprises a source of fire suppression agent and a supply line for conducting the fire suppression agent to the compartment. The supply line comprises a pressure regulating device arranged between the source and the compartment and a pressure relief valve arranged downstream of the pressure regulating device. The pressure relief valve has an outlet which distributes the agent externally of the cargo compartment.

Abstract: A fire suppression system for an aircraft cargo compartment comprises a source of fire suppression agent and a supply line for conducting the fire suppression agent to the compartment. The supply line has one or more flow control valves arranged between the source and the cargo compartment. A controller controls the flow control valve to control the supply of fire suppression agent to the cargo compartment from the source.

Abstract: There is provided a valve for controlling the release of fire suppressant from a pressurized container, said valve comprising a diaphragm configured to perforate upon action of a shockwave directed onto the surface of said diaphragm, a pyrotechnic charge arranged and adapted to combust to produce combustion products that form a shockwave directed onto the surface of said diaphragm, and a device encasing said pyrotechnic charge. The device comprises a hollow, elongate channel located over said pyrotechnic charge and directed at the center of said diaphragm so as to focus or direct said combustion products onto the center of said diaphragm. The elongate channel has a length that is at least 1.5 times its smallest width.

Abstract: A fire suppression system for a plurality of enclosures in an aircraft comprises a plurality of bottles containing fire suppression agent, a temperature sensor and a pressure sensor on each bottle for measuring temperature and pressure data of the bottle contents, an addressable bottle valve on each bottle and a control unit. The control unit is configured to analyze the temperature and pressure data for each bottle to determine adequacy of fire suppression agent content for extinguishing a fire in a particular enclosure of the aircraft. The control unit is further configured to control the bottle valves independently by using the bottle valves' addresses, in order to manage the release of fire suppression agent.

Abstract: A device for controlling the release of gas from a pressurized container includes a plug comprising a passage therethrough and a diaphragm within the passage. The diaphragm is configured to initially prevent flow of gas through said passage, and is rupturable or displaceable to allow gas to flow through said passage once said diaphragm is ruptured or displaced. The device further comprises a screw located within the plug and comprising a lance configured to move towards said diaphragm upon rotation of the screw. The lance is configured to rupture or displace the diaphragm so as to allow flow of gas through the passage and out of the plug, once the screw is rotated a predetermined amount.

Abstract: A directional valve for a fire suppression system comprises a valve member for controlling the discharge of fire suppression agent. The valve member comprises: a blocking portion to provide a closed setting for the fire suppression agent; a first orifice to provide a fully open setting for the fire suppression agent; and a second orifice to provide a restricted opening setting in which discharge of fire suppression agent is restricted. The valve member is configured so that during activation of the directional valve from a closed setting, the first orifice follows the blocking portion and precedes the second orifice in order to provide a fully open setting followed by a restricted opening setting.

Abstract: A frangible plug for use in a valve mechanism, the frangible plug including a first section having a first end and an opposing second section having a second end and a cylindrical sidewall extending between the first and second ends. Also including means for applying a force on the cylindrical sidewall of the frangible plug such that the first section fractures from the opposing second section, and wherein the means for applying a force on said cylindrical sidewall extends circumferentially around the outer circumference of the sidewall.

Abstract: A fire suppression system includes at least one first gas source containing an inert gas, at least one second gas source containing an organic halide gas, a distribution network connected with the first gas source and the second gas source to distribute the inert gas and the organic halide gas, and a controller. The distribution network includes a common manifold, input lines connecting the first gas source and the second gas source with the common manifold, output lines leading from the common manifold, and flow control devices. The controller is in communication with the distribution network and configured to distribute the inert gas responsive to a fire threat signal and determine whether to distribute the organic halide gas based upon a location of a fire threat.

Abstract: A flame detection apparatus and method includes a camera, preferably operating in the near I.R. which produces a succession of images of a space to be monitored. The image intensity of each pixel in each image is converted to a binary value by comparing it with the average intensity value for that image. For each pixel in an image the average intensity value for all of the images is calculated. The binary intensity value of each pixel in an image is then compared with the binary intensity value of the corresponding pixels in all the other images to produce a crossing frequency value dependent on the number of times those binary values change state. The average intensity values and the crossing frequency values are then processed for each pixel according to a predetermined relationship to produce a constant. If the values of this constant for a cluster of adjacent pixels are found to be the same or nearly so, this is considered to indicate a flame.

Abstract: A flame sensor comprises a cell (10) containing an infra-red absorptive fluid such as carbon dioxide gas. Heating caused by absorption of the infra-red radiation is detected by measuring a resulting temperature or pressure change.

Abstract: Apparatus for detecting particulates (46) within a medium in a chamber (10) comprises a photo-detector (14) which is maintained at a stable low temperature by a Peltier type cooling device (42). Scattered light from the particulate (46) is focused by a spherical lens (34) onto the input face (30) of a rod lens (22). The latter has an optical pitch of 0.5 and transfers the image to its output face (25) whence it passes via a light pipe (18) to the sensitive area (16) of the photo-electric device (14). The rod lens (22) provides an inexpensive means for transferring the light and which provides a thermal barrier. Thus, although the photo-electric device (14) is held at a low temperature, the input face (30) of the rod lens (22) can be held at the temperature of the medium within the chamber (10) and is not subjected to the formation of mist or ice.

Abstract: A high sensitivity smoke detector comprises a cylindrical housing incorporating a sampling chamber through which air to be sampled is forced. A modulated light source, such as a laser, directs modulated light through the chamber to a beam dump. The light beam is offset from the axis of the housing by an acute angle of between 15 and 50 degrees. If any smoke particles are positioned within a sampling volume, the light is scattered along a path defined by baffles to an axially positioned light sensor whose electrical output is passed through a phase-sensitive detection circuit which is referenced by the frequency at which the light source is modulated, so as to produce an output dependent on the light scattered by the smoke particles.

Abstract: An electrical quenching circuit for detecting, and quenching, avalanches in an avalanching device (5), comprises a TTL comparator (14) having one of its inputs (24) fed with a predetermined potential via a potential divider (18,20) and a voltage reference (22). When a switchable current source (6) is in its low impedance state, and when the device (5) is quiescent, diodes (10 and 16) conduct and input (12) is held at the potential of the voltage reference (22). Comparator (14) is in one stable state. Variations in the voltage reference affect both comparator inputs substantially equally. When the device (5) avalanches, the current from source (6) is diverted through the device and the diodes (10 and 16) cease to conduct. The potential at comparator input (12) falls and, at a critical value, switches the comparator to its other stable state. This is indicated by a pulse on line (34). The output on line (28) switches current source (6) into its high impedance state and quenches the avalanche in the device (5).

Abstract: Suppression apparatus for suppressing detonations in a pipeline which may contain an explosible vapor comprising suppressant discharge units for discharging a suppressant substance into the pipeline within a predetermined operating time. Detectors are positioned upstream of the suppressor means by sufficient distance in relation to the expected speed of travel of the detonation front along the pipeline, and in relation to the predetermined operating time of the suppressant discharge units, that the pipeline in the region of the discharge units will be supplied with an amount of suppressant which is sufficient to ensure that the detonation is suppressed when it reaches the discharge units. The suppressant may be a powder or water. Mechanical arresting means may also be provided such as a valve for positively blocking the pipeline in the event of the detection of a detonation, and/or the pipeline may have a membrane which is ruptured by the detonation so as to vent it to atmosphere.

Abstract: An oxygen supply system for use in an aircraft has four check valves (19) each having an inlet connected to a source of oxygen, and an outlet connected by a flexible hose (17) to a face mask (13). The check valve (19) associated with each face mask has a detachable pin (26) forming part of a collar (27) which embraces the hose (17) and is tethered to a looped section (29) of the hose. When the pin is detached from the check valve, by pulling the face mask down, oxygen is supplied to the mask.

Abstract: A circuit arrangement for electrically firing a load, such as the rocket motor of a projectile, at a predetermined time after it has been ejected from a predetermined path (such as the barrel of a gun) comprises a capacitor which is charged up through bore-rider contacts sensing ejection of the projectile, a resistor and two diodes. A further diode blocks a capacitor discharge path in which the load is connected. Closure of the bore-rider contacts initiates two timers. These are of different type, so as to minimize the risk of double failure, and have the same predetermined time period. At the end of this period, they respectively close switches which abruptly shifting the potential on the positive plate of the capacitor to zero. The diode 32 in the capacitor discharge path is now unblocked and discharge current passes through the load and fires it.

Abstract: A radiation detection arrangement is described using a layer of pyroelectric material such as polyvinylidene fluoride positioned between two electrodes. One electrode has a radiation-reflecting front surface and is coated with material having selected radiation absorbing characteristics. This material absorbs radiation lying within a predetermined wavelength band and this therefore heats the material and produces an electrical output. Radiation lying outside the absorption band of material is unabsorbed and is reflected by the reflecting surface. No heating takes place and no corresponding electrical output is produced. A radiation-selective detector is therefore produced without the need for optical filters.

Abstract: A control assembly is described for controlling the flow of gas from a gas generating unit into a gas bottle to be charged. The bottle cannot be charged until a latch has been pushed clear by means of a button and until an operating lever has been moved into an unactuated position. The button is then released to latch the bottle and the operating lever is moved to the actuated position to close a micro-switch in series with a second micro-switch which is only closed when the neck of the bottle is properly inserted. These micro-switches electrically energize an ignition unit and gas generation starts. Gas passes through a bore in a piston and a pin carried thereby and initially escapes around the outside of the gas bottle neck thus purging contaminants. The piston and pin now commence to move under the action of the gas pressure and the distal end of the pin sealingly enters the bottle. Gas pressure opens a check valve in the bottle neck and charges the bottle.

Abstract: For spinning up a gyroscope rotor, a motive power generating unit is used which contains a pyrotechnic gas-generating substance in the form of an azide composition. When electrically ignited, it produces a jet of filtered nitrogen gas which impacts on buckets in the periphery of the rotor and spins it up to speed. The gas generating unit can be used for generating motive power for other purposes.