Particle separation and detection apparatus
First Claim
1. A particle detecting apparatus for detecting the presence of particles in a gaseous fluid, comprisinga measuring chamber for receiving the gaseous fluid and defined by wall means, light sensing means having a field of view extending in the chamber, means for defining a sampling volume in the chamber, means for defining a light path in the chamber and which intersects the sampling volume, at least one pair of light emitters mounted to direct emitted light across the chamber in opposite directions along the light path towards the sampling volume, whereby particles carried by the gaseous fluid into the sampling volume scatter some of the light therein for detection by the light sensing means, the light emitters of the pair normally simultaneously emitting light and at least one thereof having a selectable light detecting mode, and control means operative intermittently to switch said one of the light emitters into the light detecting mode so that said one light emitter when switched into the light detecting mode responds to light directly received from the other emitter of the pair along the light path and produces a corresponding output which is dependent on contamination in the light path.
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Accused Products
Abstract
Particle detecting apparatus for detecting other particulate matter comprises a measuring section and an input/output section removably attached together. A measuring chamber receives gaseous fluid by diffusion from a receiving chamber connected via an inlet to an area being monitored. The measuring chamber comprises a cylindrical body housing pairs of light emitting diodes positioned diametrically opposite, and directing light towards, each other through a sampling volume viewed by a photo-diode through a viewing aperture. The photo-diode detects light scattered by particles in the sampling volume. A glass tube protects the LEDs from contamination and can easily be cleaned or removed. Each LED can temporarily be de-energised in turn so as to act as a light detector, its output in response to light received from the opposite LED being thus a measure of any contamination. The measuring and input/output sections can easily be separated for servicing or replacement.
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Citations
29 Claims
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1. A particle detecting apparatus for detecting the presence of particles in a gaseous fluid, comprising
a measuring chamber for receiving the gaseous fluid and defined by wall means, light sensing means having a field of view extending in the chamber, means for defining a sampling volume in the chamber, means for defining a light path in the chamber and which intersects the sampling volume, at least one pair of light emitters mounted to direct emitted light across the chamber in opposite directions along the light path towards the sampling volume, whereby particles carried by the gaseous fluid into the sampling volume scatter some of the light therein for detection by the light sensing means, the light emitters of the pair normally simultaneously emitting light and at least one thereof having a selectable light detecting mode, and control means operative intermittently to switch said one of the light emitters into the light detecting mode so that said one light emitter when switched into the light detecting mode responds to light directly received from the other emitter of the pair along the light path and produces a corresponding output which is dependent on contamination in the light path.
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22. A particle detecting apparatus for detecting the presence of particles in a gaseous fluid, comprising
a measuring chamber for receiving the gaseous fluid and defined by wall means, light sensing means having a field of view extending in the chamber, means for defining a sampling volume in the chamber, means for defining a light path in the chamber and which intersects the sampling volume, at least one pair of light emitters to direct emitted light across the chamber in opposite directions along the light path towards the sampling volume, whereby particles carried by the gaseous fluid into the sampling volume scatter some of the light therein for detection by the light sensing means, the light emitter of the pair normally simultaneously emitting light and at least one thereof having a selectable light detecting mode, and control means operative intermittently to switch one of the light emitters into the light detecting mode so that said one light emitter when switched into the light detecting mode responds to light directly received from the other emitter of the pair along the light path and produces a corresponding output which is dependent on contamination in the light path, gaseous fluid input/output means having a gaseous fluid inlet for connection to an area being monitored, a receiving chamber for receiving gaseous fluid drawn in through the inlet, and an outlet for exhaustion of the gaseous fluid from the receiving chamber, the receiving chamber being mounted in juxtaposition with the measuring chamber whereby gaseous fluid and particles therein in the receiving chamber tend to diffuse into the measuring chamber.
Specification