Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
1998-12-23
2001-03-27
Hofsass, Jeffery A. (Department: 2738)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S630000
Reexamination Certificate
active
06208252
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to smoke detection equipment, and more particularly to a tobacco smoking detection device which has the combined capabilities of detecting or sensing smoke and the flame typically used to ignite the tobacco.
BACKGROUND OF THE INVENTION
Steadily increasing awareness to the risks of tobacco smoking and the medical complications associated with second-hand smoke have recently lead to the banning of smoking in many public places. In the past, tobacco smoking has typically been barred at institutions such as schools and hospitals. Recently however, certain states, including California, have passed legislation which outlaws tobacco smoking in all public buildings, including office buildings, bars, and restaurants. However, despite the many federal, state, and local government imposed smoking prohibitions or restrictions currently in place, there are many individuals who chose to ignore such restrictions and engage in tobacco smoking in public places.
There is currently known in the prior art various tobacco smoke detection systems or devices which are operative to sense or detect moderate to heavy levels of tobacco smoke. These prior art devices typically detect such smoke through the use of dual ionization, photoelectric, or combined ionization-photoelectric smoke detection units. Since these prior art devices are operative only to detect moderate to heavy levels of tobacco smoke, they are largely ineffective in outdoor areas or in large, well ventilated rooms where the tobacco smoking activity may occur in a location which is at some distance from the smoke detector, thus not providing a sufficient level of smoke to cause the same to generate or activate a suitable alarm.
Also known in the prior art are tobacco smoking detection devices which, in addition to being operable to sense tobacco smoke, are further operable to detect or sense the infrared heat signature generated by burning cigarettes or cigars. These types of prior art tobacco smoking detection devices, like those operable to sense tobacco smoke only, are typically effective for use in small rooms such as the lavatories of airplanes or in small offices, but also lack the sensitivity needed to detect tobacco smoking in well ventilated large rooms or outdoor areas outside of a building. Additionally, though being operable to detect the infrared heat signature of a burning cigarette or cigar, such prior art devices have low sensitivity to detecting the infrared heat signature generated by burning tobacco pipes, and may generate false signals from heat sources other than a burning cigarette or cigar.
The present invention overcomes the deficiencies associated with prior art tobacco smoking detection devices, and is based on the fundamental principle that tobacco smoking is typically initiated with the actuation of a cigarette lighter or the burning of a match which is used to fire or ignite a cigarette, cigar, or tobacco pipe. In this respect, the present invention provides a tobacco smoking detection device which is operable to sense or detect the flame used to facilitate the lighting or firing of the tobacco. In addition to being adapted to accomplish such flame detection at substantial distances, the detection device of the present invention is also specifically configured to ignore the effects of background optical radiation, and thus not generate false alarms as a result thereof. More particularly, though being operable to detect a flame of a cigarette lighter at distances of up to about 300 feet, the present detection device is not triggered as a result of sunlight, objects heated to high temperatures from sunlight, heated car engines, building heaters, or incandescent or fluorescent lamps. The present detection device is also provided with smoke detecting capability for those instances when an individual enters into the monitored area with a previously lit cigarette, cigar or pipe, or for those instances when smoking is started via a cigarette-to-cigarette tobacco lighting process. These, and other advantages associated with the present detection device, will be discussed in more detail below.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a smoking detection device comprising a smoke sensor or detector for generating an electrical signal in response to the detection of smoke. In addition to the smoke sensor, the detection device comprises an optical sensor or detector for generating an electrical signal in response to the detection of ultraviolet radiation in a prescribed range. Typically, such ultraviolet radiation is produced by the flame of a cigarette lighter or a burning match. The present detection device may further comprise an alarm unit which is electrically connected to the smoke and optical sensors for generating an alarm signal in response to any one of the electrical signals generated by the smoke and optical sensors. The alarm unit may comprise a buzzer for purposes of generating an audible alarm, and/or an LED or other signaling device for generating a visible alarm. The alarm unit may also comprise an electronic unit which provides an audio voice warning signal to the offending smoker. The present detection device may also further comprise a power supply (e.g., a battery) which is electrically connected to the smoke and optical sensors and to the alarm unit. Additionally, it is contemplated that the present detection device may include, as an alternative to the alarm unit, a transmission unit for transmitting any one of the electrical signals generated by the smoke and optical sensors to a remote receiver unit which itself may generate an audible and/or visible alarm.
The smoke sensor of the present detection device is preferably a dual ionization smoke detection unit. The optical sensor is preferably configured to sense ultraviolet radiation in a spectral range or region (i.e., an optical band) of from about 185 nanometers to about 260 nanometers. Advantageously, since sun radiation in this particular optical domain is trapped by the atmospheric ozone layer, the noise level of false signals from sunlight is extremely low. Indeed, direct sunlight or sun radiation has no influence on the operation of the present detection device to altitudes of up to about 10,000 feet. Additionally, the sensing of ultraviolet radiation in this particular range substantially reduces the susceptibility of the optical sensor to false signals from low thermal background optical radiation generated by, for example, objects heated to high temperatures from sunlight, heated car engines, building heaters, and incandescent or fluorescent lamps. Additionally, the optical sensor is configured so as to allow the gain and sensitivity thereof to be raised to a level to reliably sense very weak optical signals, i.e., incident ultraviolet radiation of an intensity in a range of about 1 picowatt per square centimeter to about 1 nanowatt per square centimeter.
The optical sensor is also preferably configured to sense ultraviolet radiation at a wide spacial detection angle of up to about 360 degrees. However, the optical sensor may be provided with an optical concentrator for narrowing the spacial detection angle to no greater than about 60 degrees. The optical concentrator may comprise either a parabolic reflective light concentrator or a refractive ultraviolet transparent lens. In those embodiments wherein the optical sensor is not provided with an optical concentrator, it possesses the capability to detect the flame produced by a cigarette lighter or a burning match at a distance of up to about 60 feet. This distance may be increased to up to about 300 feet by providing the optical sensor with a suitable optical concentrator. The optical sensor is preferably selected from the group consisting of vacuum solar blind photomultiplier tubes, semiconductor sensors with ultraviolet filters, solar blind avalanche vacuum photodiodes, gas-filled photodiodes, and semiconductor photodiodes.
Further in accordance with the present invention, there
Hofsass Jeffery A.
Previl Daniel
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