Abstract: Devices, systems, and methods for providing smoke detectors are described herein. One smoke detector of a fire sensing system includes a circuit board body, having a set of front scattering emitting light sources located on one side of an optical chamber, a receiver of front scattering light beams from the front scattering emitting light sources and backward scattering light beams, and a set of backward scattering emitting light sources located between the set of front scattering emitting light sources and the receiver, the backward scattering light beams emitted from the backward scattering emitters.

Abstract: Devices, systems, and methods for providing point heat detectors based on surface mounted thermistors are described herein. One circuit board for a point heat detector of a fire sensing system includes a circuit board body having number of corners, at least one hole provided in the circuit board body proximate to one of the corners, and a surface mounted thermistor mounted on at least one corner.

Abstract: An optical smoke detector includes a radiant energy source and a sensor. The source and the sensor are carried by an optical block that provides a fixed orientation therebetween and barriers therebetween. The barriers reduce noise and false alarming due to bugs, dust, water vapor, and other intrusive elements. The barriers can include V-shaped members at a selective angle relative to center lines of the source and the sensor.

Abstract: A smoke detector with an improved double optical chamber is provided. The smoke detector can include a chamber cover, a chamber base, an optical block, and a printed circuit board, wherein a smoke chamber is bound by the chamber cover, the chamber base, and the optical block, wherein a monitoring chamber is bound by the chamber base, the optical block, and the printed circuit board, wherein the monitoring chamber is closed to access outside of the smoke detector, and wherein radiation from only the monitoring chamber produces a non-zero clean air value of the detector.

Abstract: An aspirated smoke detector with an improved optical chamber is provided. The aspirated smoke detector can include a base, an optical block housed within the base, the optical block housing an emitter and a receiver, and a chamber cover disposed over the base and the optical block to form an optical chamber therebetween. The chamber cover can capture light emitted by the emitter and reflect the captured light within the chamber cover while avoiding multiple back reflections of the captured light.

Abstract: A smoke detector with an improved double optical chamber is provided. The smoke detector can include a chamber cover, a chamber base, an optical block, and a printed circuit board, wherein a smoke chamber is bound by the chamber cover, the chamber base, and the optical block, wherein a monitoring chamber is bound by the chamber base, the optical block, and the printed circuit board, wherein the monitoring chamber is closed to access outside of the smoke detector, and wherein radiation from only the monitoring chamber produces a non-zero clean air value of the detector.

Abstract: An aspirated smoke detector with an improved optical chamber is provided. The aspirated smoke detector can include a base, an optical block housed within the base, the optical block housing an emitter and a receiver, and a chamber cover disposed over the base and the optical block to form an optical chamber therebetween. The chamber cover can capture light emitted by the emitter and reflect the captured light within the chamber cover while avoiding multiple back reflections of the captured light.

Abstract: A method and apparatus of determining gas transport time from an input port to first and second ultrasonic detectors in a flow conduit for an aspirated smoke detector are provided. The method includes first measuring a transit time of ambient air between the detectors. Then, a different gas is injected into the conduit, and the time of injection is stored. The transit time is measured at least intermittently between the two ultrasonic detectors until a change therein is detected. A time of detected change is subtracted from the time of injection to establish a transport time for the aspirated smoke detector.

Abstract: An optical smoke detector includes a radiant energy source and a sensor. The source and sensor are carried by an optical block which provides a fixed orientation therebetween and barriers therebetween. The barriers reduce noise and false alarming due to bugs, dust water vapor and other intrusive elements. The barriers can include V-shaped members at a selective angle relative to center lines of the source and sensor.