Cerberus Ag

Baker Industries, Inc.

Irving L Ellner

Samuel Raber

James A Best

A focused beam of light from a light source is directed into a closed smoke chamber, having inlets for admitting smoke particles, toward a reflector which reflects and refocuses the beam back into the light source, the direct beam and the reflected beam passing through a test zone within the chamber. In the event that smoke particles enter the test zone, the direct and reflected beams strike and bounce off of those particles to produce scattered radiation that will be picked up and detected by a light responsive sensor to generate an alarm signal. By closely controlling, rather than baffling the light, optimum operation is obtained, efficiency is enhanced and false alarms are minimized. Additionally, to prevent any stray light from bouncing off of undesired dirt and dust in the chamber and being received by the light sensor, resulting in a false alarm, surfaces of the chamber are provided with parallel grooves for accumulating that dirt and dust, and the light sensor field of view is focused on an attenuating light trap. Stray light impinging on the grooved surfaces becomes attenuated and absorbed so there will be no reflections, and light entering the light trap is reduced to a negligible level.

Optical smoke detector

An intrusion detection system includes a vibration sensor, and a gate circuit operable to provide an output signal only after the vibration sensor produces a first signal, and thereafter a second, separate signal within a preassigned 'sensing window' period. To accomplish this, a timer circuit initiated by the sensor determines a timing interval, and a delay circuit coupled to the timing circuit prevents switching of the gate circuit until preset delay time has elapsed. After the delayed time, if a second sensor output signal is received before expiration of the timing interval, the gate circuit switches and passes a signal through an integrated circuit amplifier stage, and a driver circuit to energize an output unit. The sensitivity of the vibration sensor can be adjusted. The integrated circuit stage includes circuitry for maintaining the alarm signal even if the system is switched to off after it goes into alarm. The same stage also checks periodically for a low battery condition, and provides an output warning signal if the battery level falls below a preset level.

Growing community of inventors

Hopatcong, NJ, United States of America

Irving L Ellner