Abstract: A single active element performs the multiple functions of regulating DC voltage level from an AC source supplied to charge a battery and of coupling the battery to power an emergency system such as an emergency lighting system upon loss of the AC source. Preferably, the single active element also performs a third function of disconnecting the battery from the emergency system in time to prevent over discharge and consequent permanent damage to the battery.

Abstract: A flame detector which is capable of discriminating between hydrocarbon fires and background radiation produced by the sun, artificial light or black body radiation. Two radiation sensors are provided, each being responsive to separate known radiation peaks produced by a hydrocarbon fire. Logic circuitry is provided which produces an alarm signal only when the radiation received by each sensor is above a predetermined value, and when the radiation received by one specified sensor is greater than the radiation received by the other sensor.

Abstract: A photo-electric smoke detector operating on the reflected light principle which has a rate detector for detecting the rate of increase of smoke concentration. When the rate exceeds a predetermined value, the rate detector causes the intensity of the smoke detector light source to increase, thereby increasing the sensitivity of the detector. In one embodiment of the invention, after the intensity of the light has been increased by the rate detector, it is maintained at the higher intensity for a predetermined time, even if the rate of increase of smoke concentration falls below the predetermined value.

Abstract: A smoke detector system utilizing remote detectors of the photo-electric type connected to a central control panel. In one embodiment means is provided for monitoring both the signal lead and power lead, and in another embodiment, means is also provided for monitoring the condition of the detector light source. A normally illuminated compensating cell is provided in series with the smoke detection cell, with the bottom of the compensating cell being maintained a predetermined voltage above ground to provide a monitor voltage at the junction of the cells. The output signal lead is connected to the junction of the compensating cell and the smoke cell, and feeds a high impedence input amplifier, the output of which goes to the control panel. Means is provided at the panel for responding to the presence of an alarm signal on the signal lead or the absence of the monitor voltage which might be caused by a break in the signal lead, or the power lead.

Abstract: A smoke detector of the photo-electric type having a photo-responsive device viewing a volume illuminated by a light beam, in which a test member is provided for being temporarily positioned in the light beam so that one side of said member is exposed to the light and the other side is in the view of the photo-responsive device.The test member has an area near the forward edge which is thin in relation to the thickness of the rest of the test member. In one embodiment of the invention this area is thin enough to be translucent, so that the translucent area illuminated by the beam simulates a predetermined percentage of smoke in the beam with a high degree of accuracy, since the transmission characteristics of the translucent area can be consistently maintained within production tolerances, and the exact position of the translucent area in the light beam for the smoke simulation is not critical.

Abstract: A smoke detector of the photo-electric type having a photo-responsive device viewing a volume illuminated by a light beam, in which a test member is provided for being temporarily positioned in the light beam so that one side of said member is exposed to the light and the other side is in the view of the photo-responsive device.The test member has a translucent area at the forward edge which is small in relation to the cross-sectional area of the light beam. The translucent area illuminated by the beam simulates a pre-determined percentage of smoke in the beam with a high degree of accuracy since the transmission characteristics of the translucent area can be consistently maintained within production tolerances, and the exact position of the translucent area in the light beam for the smoke simulation is not critical.

Abstract: A smoke detector and housing assembly therefore in which the housing components are designed to allow rapid assembly of the detector with a minimum amount of labor. In a preferred embodiment of the invention a retainer for a photo-cell and light source is provided with a medial portion retaining the photo-cell and portions extending forwardly from the ends of the medial portion for projecting a light beam through the field of view of the photo-cell. The retainer is molded in two similar halves and fastened together after assembly of the photo-cell, light source, and other components therein.A base plate is provided with suitable apertures for receiving the forwardly projecting portions of the retainer so that after assembly they protrude from the forward face thereof. A cylindrical member and cover are mounted on the forward face of the base plate between the forwardly projecting portions of the retainer, forming a dark chamber across which the light beam projects, and into which the photo-cell views.

Abstract: A smoke detector operating on the reflected light principle, utilizing a pulsing light source and means requiring several consecutive pulses of light reflected from smoke to actuate an alarm. During normal standby operation, the light pulses at a predetermined slow rate. When smoke is present, the first pulse of light reflected from the smoke causes the pulse rate to increase for a predetermined number of pulses or for a predetermined short time, so that the number of reflected pulses required to actuate the alarm are received in a shorter time. The time to alarm is thereby shortened without increasing the current drain of the device and without shortening the life of the pulsing light source.