Abstract: An embodiment of a flame detector coverage verification system includes an optical source for generating a light beam, and a light-path control unit connected to the optical source and configured to direct the beam through a range of movements about a center line direction of the flame detector to visually demarcate an area that falls within the flame detector's field of view. An indicator device configured to visually indicate a pan direction of the detector optical center line. A tilt indicator is configured to determine and visually display the tilt angle of the detector with respect to a ground plane. A hub structure temporarily attaches the control unit to the flame detector, the control unit pivotally connected to the hub structure so that the optical source light beam is oriented perpendicular to a ground plane.

Abstract: An ultrasonic gas leak detector system for locating a source of ultrasonic airborne energy is described. An exemplary embodiment includes a plurality of spatially separated ultrasonic gas leak detectors, each configured to generate signals indicative of detected angles of arrival of received ultrasonic energy at the respective detectors. A locator processor receives the signals generated by the detectors, and is configured to process the signals to determine a location in three dimensions of the source of the ultrasonic energy received at the detectors and provide locator processor output signals indicative of the location.

Abstract: An embodiment of a flame detector coverage verification system includes an optical source for generating a light beam, and a control unit configured to point the beam in a direction generally co-aligned with an optical center line of the flame detector and through a range of movement about the direction to visually demarcate an area that falls within the flame detector's field of view. In one embodiment, the control unit includes a movable mirror to deflect the laser beam. The system may include an indicator device configured to determine and visually indicate a pan direction of the detector optical center line with respect to a defined direction, and a declination indicator configured to determine and visually display the tilt angle (angle of declination) of the detector optical center line with respect to a ground plane.

Abstract: An ultrasonic gas leak detector and test method, configured to discriminate the ultrasound generated by a pressurized gas leak into the atmosphere from ultrasound generated by man-made ultrasonic sources. In an exemplary embodiment an ultrasonic gas leak detector is able to identify a remote ultrasonic test source as a known test source and to initiate a test sequence instead of alarm. An output function generates detector outputs in dependence on the test mode initiation. The ultrasonic gas leak detector may also identify various other man-made ultrasonic sources as being neither gas leaks nor remote test sources but as nuisance or hostile sources to be identified as such. The test method utilizes a narrowband test source at a known ultrasonic frequency to ensonify the detector.

Abstract: An embodiment of a directional ultrasonic gas leak detector includes an array of spaced MEMS microphones, each responsive to incident airborne ultrasonic energy from gas leak sources to generate a microphone signal. A beamforming processor is responsive to the microphone signals from the array to generate processor output signals indicative of estimated angles of arrival of ultrasonic energy incident on the array. The array may be disposed in an explosion proof housing structure for operation in hazardous location, or implemented as an intrinsically safe device. In another embodiment, a display is responsive to the processor output signals to generate an image representative of a surveilled scene with the estimated magnitudes of incident energy at beam directions overlaid onto the image.

Abstract: Exemplary embodiments of a flame detector and operating method. Optical energy is received at one or more optical sensors, and the detector processes the energy to determine whether the received energy is from a known remote test source. If so, the flame detector is operated in a test mode. If the processing indicates that the received optical energy is not a test signal, the flame detector is operated in a flame detection operating mode. The detector processing uses an artificial neural network in an exemplary embodiment in the flame detection operation mode.

Abstract: An ultrasonic gas leak detector is configured to discriminate the ultrasound generated by a pressurized gas leak into the atmosphere from false alarm ultrasound. An exemplary embodiment includes multiple acoustic sensors for detecting acoustic energy and providing sensor signals, including a broadband sensor and at least one narrowband sensor, and an electronic controller responsive to the sensor signals. In one exemplary embodiment, the electronic controller is configured to provide a threshold comparator function to compare a sensor signal value representative of sensed ultrasonic energy to a gas detection threshold value, and an Artificial Neural Network (ANN) function for processing signals derived from the multitude of sensor signals and applying ANN coefficients configured to discriminate false alarm sources from gas leaks. An output function generates detector outputs in dependence on the threshold comparator output and the ANN output.

Abstract: An ultrasonic gas leak detector is configured to discriminate the ultrasound generated by a pressurized gas leak into the atmosphere from false alarm ultrasound. An exemplary embodiment includes a sensor for detecting ultrasonic energy and providing sensor signals, and an electronic controller responsive to the sensor signals. In one exemplary embodiment, the electronic controller is configured to provide a threshold comparator function to compare a sensor signal value representative of sensed ultrasonic energy to a gas detection threshold value, and an Artificial Neural Network (ANN) function for processing signals derived from the digital sensor signals and applying ANN coefficients configured to discriminate false alarm sources from gas leaks. An output function generates detector outputs in dependence on the threshold comparator output and the ANN output.

Abstract: An explosion-proof system for generating acoustic energy. An exemplary embodiment of the system includes a main housing defining an open housing space and an opening. A cover structure is configured for removable attachment to the main housing structure to cover the opening and provide an explosion-proof housing structure. The cover structure includes an integral head mass. An acoustic energy emitting assembly includes the head mass, and an excitation assembly disposed within the explosion-proof housing structure. An electronic circuit is disposed within the explosion-proof housing structure to generate a drive signal for driving the excitation assembly to cause the acoustic energy emitting assembly to resonate and generate acoustic energy. In one embodiment the acoustic energy is a beam of ultrasonic energy useful for testing ultrasonic gas detectors. A method is also described for testing ultrasonic gas leak detectors using an ultrasonic source.

Abstract: An exemplary embodiment of an acoustic sensor system includes a housing structure, and a miniaturized acoustic transducer mounted in the housing structure. A flame arrestor structure is mounted on or within the housing structure between the acoustic transducer and the external environment, so that ambient acoustic energy passes through the flame arrestor structure before reaching the acoustic transducer.

Abstract: An ultrasonic gas leak detector is configured to discriminate the ultrasound generated by a pressurized gas leak into the atmosphere from false alarm ultrasound. An exemplary embodiment includes multiple acoustic sensors for detecting acoustic energy and providing sensor signals, including a broadband sensor and at least one narrowband sensor, and an electronic controller responsive to the sensor signals. In one exemplary embodiment, the electronic controller is configured to provide a threshold comparator function to compare a sensor signal value representative of sensed ultrasonic energy to a gas detection threshold value, and an Artificial Neural Network (ANN) function for processing signals derived from the multitude of sensor signals and applying ANN coefficients configured to discriminate false alarm sources from gas leaks. An output function generates detector outputs in dependence on the threshold comparator output and the ANN output.

Abstract: A gas imaging system for remotely detecting gas emissions by passive images of infrared radiation includes an optical system having a field of view. The optical system has a lens, an optical filter system for filtering light passed through the lens, and a photosensitive array located at the focal plane of the optical system to produce multi-spectral infrared image data of a scene under observation. A multi-spectral image processing system is configured for processing the image data produced by the photosensitive array to detect hazardous gas emissions and to discriminate against infrared radiation emitted by false alarm sources. Some embodiments may be configured for flame detection. Other embodiments may be configured for gas and flame detection.

Abstract: A flame detection system includes a plurality of sensors for generating a plurality of respective sensor signals. The plurality of sensors includes a set of discrete optical radiation sensors responsive to flame as well as non-flame emissions. An Artificial Neural Network may be applied in processing the sensor signals to provide an output corresponding to a flame condition.

Abstract: A semiconductor article suitable for use in the detection of hydrogen gas in the atmosphere. The article comprises a film of palladium deposited onto a semiconductor film of stannic oxide which is positioned on a suitable substrate together with a resistance heating element. In some cases, the stannic oxide film is provided with a dopant to improve the operation of the article.