Abstract: A method for calibrating a smoke detector includes adjusting the sensitivity of the smoke detector to get a consistent predetermined response over the expected operating range. The sensitivity is generally consistent for all detectors and an independent offset value is determined for each detector. This offset value basically corresponds to the signal from the detector in a clean atmosphere. The sensitivity of the smoke detector is determined by measuring the response at different levels of obscuration and then appropriately adjusting the output of the light source of the detector. This process is repeated until the desired sensitivity is achieved. Thereafter, the offset value is measured or calibrated and stored in the smoke detector for use in setting alarm values.

Abstract: A method for calibrating a smoke detector includes adjusting the sensitivity of the smoke detector to get a consistent predetermined response over the expected operating range. The sensitivity is generally consistent for all detectors and an independent offset value is determined for each detector. This offset value basically corresponds to the signal from the detector in a clean atmosphere. The sensitivity of the smoke detector is determined by measuring the response at different levels of obscuration and then appropriately adjusting the output of the light source of the detector. This process is repeated until the desired sensitivity is achieved. Thereafter, the offset value is measured or calibrated and stored in the smoke detector for use in setting alarm values.

Abstract: A method for calibrating a smoke detector includes adjusting the sensitivity of the smoke detector to get a consistent predetermined response over the expected operating range. The sensitivity is generally consistent for all detectors and an independent offset value is determined for each detector. This offset value basically corresponds to the signal from the detector in a clean atmosphere. The sensitivity of the smoke detector is determined by measuring the response at different levels of obscuration and then appropriately adjusting the output of the light source of the detector. This process is repeated until the desired sensitivity is achieved. Thereafter, the offset value is measured or calibrated and stored in the smoke detector for use in setting alarm values.

Abstract: A method for calibrating a smoke detector includes adjusting the sensitivity of the smoke detector to get a consistent predetermined response over the expected operating range. The sensitivity is generally consistent for all detectors and an independent offset value is determined for each detector. This offset value basically corresponds to the signal from the detector in a clean atmosphere. The sensitivity of the smoke detector is determined by measuring the response at different levels of obscuration and then appropriately adjusting the output of the light source of the detector. This process is repeated until the desired sensitivity is achieved. Thereafter, the offset value is measured or calibrated and stored in the smoke detector for use in setting alarm values.

Abstract: A smoke detection chamber for use in a photoelectric smoke detector. The smoke detection chamber comprises a side wall with a double row of generally rectangular vanes arranged to provide a labyrinth extending generally around the entire side wall for ingress and egress of smoke particles, a top and a bottom. A mounting arrangement for a photoemitting diode is provided in the side wall of the smoke detection chamber so that a light beam from a photoemitting diode is transmitted across the smoke detection chamber. The mounting arrangement extends from and is spaced from the bottom to provide minimal interference for entry of smoke particles. The bottom of the smoke detection chamber has an opening therein with a shielding arrangement thereabout open to the chamber for a photodiode detector, the opening and shielding arrangement being located between the centerline of the smoke detection chamber and the mounting arrangement in the side wall of the chamber.

Abstract: A smoke detection chamber for use in a photoelectric smoke detector. The smoke detection chamber comprises a side wall with a double row of generally rectangular vanes arranged to provide a labyrinth extending generally around the entire side wall for ingress and egress of smoke particles, a top and a bottom. A mounting arrangement for a photoemitting diode is provided in the side wall of the smoke detection chamber so that a light beam from a photoemitting diode is transmitted across the smoke detection chamber. The mounting arrangement extends from and is spaced from the bottom to provide minimal interference for entry of smoke particles. The bottom of the smoke detection chamber has an opening therein with a shielding arrangement thereabout open to the chamber for a photodiode detector, the opening and shielding arrangement being located between the centerline of the smoke detection chamber and the mounting arrangement in the side wall of the chamber.

Abstract: The present invention relates to an electronic heat detector having a self diagnostic mode. The heat detector is able to test the operation of a thermistor utilized for the temperature indicator of the heat detector. The thermistor is tested by applying electrical energy to the thermistor at a sufficient level for sufficient time to cause a measurable increase in the temperature of the thermistor. This level of increase of temperature of the thermistor is measured against an acceptable range for proper operation of the heat detector. The present invention also relates to a method for determining whether a heat detector is operating within acceptable limits, the heat detector utilizing a thermistor for temperature indication by the heat detector.

Abstract: The present invention provides for a smoke detection chamber and a photoelectric smoke detector containing the smoke detection chamber. The smoke detection chamber has side walls with openings provided therein for ingress and egress of smoke particles, a top and a bottom. A photoemitting diode is mounted in a mounting arrangement in the side wall of the smoke detection chamber to transmit a light beam across the smoke detection chamber without directly impinging upon either the top or the bottom surfaces. The bottom of the smoke detection chamber has an opening with a shielding arrangement thereabout open to the chamber located between the centerline of the smoke detection chamber and the mounting arrangement in the side wall of the chamber.

Abstract: The present invention provides a method for detecting whether an alarm circuit is operating outside its sensitivity range, the alarm circuit having a background signal and a preset alarm threshold signal. The method involves: a) multiplying the background signal by a first gain factor to produce a first test signal; b) comparing the first test signal against an alarm threshold signal; c) multiplying the background signal by a second gain factor less than the first gain factor to produce a second test signal; and d) comparing the second test signal against the alarm threshold signal. The alarm circuit is operating outside its sensitivity range when the first test signal is less than the alarm threshold signal or the second test signal is greater than the alarm threshold signal.