Graviner Limited

Kidde Technologies Incorporated

Kidde Fire Protection Limited

Kidde IP Holdings Limited

Detector Electronics Corporation

Kidde Graviner Limited

Brian David Powell

David J Spring

Mark P Fazzio

Dharmendr Len Seebaluck

Robert Glaser

Robert L Farquhar

Robert James Lade

Scott Ayers

Peter E Moore

Louis W Rance

Parviz James Monem

Max Daniel Allsworth

David John Probyn

Disclosed is a measurement system for a dry powder agent including a nozzle to direct the dry powder agent, and an indicator operable to recognize a dry powder agent discharge event. In an exemplary method, a velocity of the powder exiting the nozzle may be computed, and an agent concentration calibration curve may be selected.

Velocity survey with powderizer and agent flow indicator

A fire detection system for monitoring a volume containing fluid, typically air, for the presence of smoke particles is disclosed. A conduit for receiving the fluid, and any smoke particles therein, and directing the fluid to a smoke detector has a plurality of inlets formed therein. A respective temperature sensor is associated with each of the inlets which generate a signal indicative of a change in temperature in the region of the inlet. In the embodiments, the temperature sensor comprises one or more fiber Bragg gratings. The fiber Bragg gratings preferably have different grating periods. The reflected light from each fiber Bragg grating is returned back down the fiber optic cable and redirected via a 2&#xd7;1 coupler to a wavelength detection system and a personal computer. The combination of wavelength detection system and personal computer 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. The location of the said variation along the fiber optic cable is advantageously detectable. The system described is highly sensitive to smoke, but can advantageously also provide an indication of the location of the smoke source, because any variation in temperature at any one of the smoke inlets is also detected, the location of the sensor being known.

Fire detection

A sensor head for a dry powder agent according to an exemplary aspect of the present disclosure includes a housing defined along an axis along which light is communicated, the housing defines a multiple of apertures transverse to the axis, the multiple of apertures in communication with a measurement volume along the axis. A mirror is within the housing to reflect the light through the measurement volume.

Sensor head for a dry powder agent

A smoke detector () has a spherical chamber () including a plurality of holes () for allowing smoke and other particles to enter the chamber. The majority of the internal surface () of the chamber () 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 () is coated with a light absorbing material () such as a matt black coating. A scatter sensor () is directed towards the absorbing coating (), and an integrating detector () is configured to detect radiation directly from the entire Lambertian surface. A first LED () emits blue light into the chamber (), and a second LED () emits infrared light into the chamber. Processing means (and) are provided to analyse the signals from the detectors (), including means for discriminating between signals from the sensors indicative of different frequencies of received radiation. The processing means can distinguish between different smoke types, such as white/grey smoke and black smoke, and can also distinguish between smoke and other particles.

Smoke detector

A smoke detector is disclosed in which smoke particles are detected by the collection and detection of blue light and infra-red radiation which are emitted into a predetermined path through a scattering volume where the particles may be present. The scattered blue light and the scattered infra-red radiation are collected by an ellipsoidal mirror and focussed onto a suitable detector and then compared to produce an output which indicates either that the detected particles are smoke particles or that they are not smoke particles. The radiation collected by the mirror has been scattered through angles substantially less than 45&deg; and preferably between about 10&deg; and 35&deg;.

High sensitivity particle detection

An elongate temperature sensor comprises two electrical conductors having temperature sensitive insulating material between them whose resistance and capacitance varies with temperature but according to respectively different known relationships. An alternating waveform is applied across the sensor through a known resistor. The amplitudes of the voltage waveforms developed across the known resistor and across the sensor are compared and the phase difference between them measured to determine the corresponding resistance and capacitance values of the sensor. The measured value of one parameter is then substituted into the respective known relationship to produce a corresponding temperature value for the sensor. This temperature value is then substituted into the relationship for the other parameter to calculate a notional value for that parameter. If that notional value differs from the measured value, this is used to produce an indication that the sensor is not being uniformly heated but has an overheated sectional part. By means of further processing, the length and position of the overheated section and its actual temperature can be determined.

Temperature detecting methods and systems

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.

Radiation detection arrangements

A flame detector has a sensor for producing a digital waveform representing a flickering flame. Its turning points are detected and the magnitudes between successive such points are measured. The value of each such magnitude is plotted on a graph whose horizontal axis represents the current value and whose vertical axis represents the immediately preceding value. Points are produced lying in regions away from the diagonal and from the axes. If the detected waveform originates from a regularly varying interfering source, the corresponding points will lie on or near the diagonal. If the interfering source is a waveform undergoing step changes, the corresponding points will lie adjacent to the axes. In this way, discrimination between flames and interfering sources of radiation can be made.

Recognition and processing of waveforms

An overheat detector comprises an optical fiber connected at one end to a light source and at the other end to a photodiode for monitoring the light level transmitted through the fiber. When the light level falls below a predetermined threshold due to melting of the fiber, an alarm signal is output. The temperature at which the alarm signal is output depends upon the material of which the light conducting part of the fibre is constructed.

Fire and overheat detection

A fire and explosion detection and suppression system protects two physically adjacent zones in each of which there is a UV sensor and an IR sensor. In each zone, simultaneous detection, by the pair of sensors, of sufficient respective levels of UV and IR causes an AND gate to set off suppressor units to discharge suppressant into the zone being protected. Some of this suppressant may drift into the adjacent zone and may attenuate UV radiation in that zone. Thus, for at least a temporary period, that zone may be incapable of detecting a subsequently occurring fire or explosion. Therefore, by means of a latching circuit the output signal of an operating one of the AND gates temporarily renders the circuit of the adjacent zone capable of operating independently of UV radiation.

Fire and explosion detection and suppression

A radiation-responsive system is described for measuring the distance to a fire. A radiation detector produces an output I1 dependent on the intensity of radiation received in a narrow wavelength band where there is insignificant atmospheric absorption while another detector produces an output I2 dependent on the intensity received in a narrow wavelength band where there is significant atmospheric absorption. The ratio I1/I2 will thus be dependent on the distance to the fire because each of the terms will be equally affected by the normal square law decrease of intensity with distance, but the term I2 will decrease as the distance increases. A ratio unit measures the ratio I1/I2 which is converted into digital form and passed to a processing unit. The latter is programmed according to the precise form of the relationship between I1/I2 and distance to produce an output proportional to distance.

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Maidenhead, United Kingdom

Brian David Powell