Patent Application
20060257285
The present invention generally relates to a device for determining the presence of an atmospheric component and more particularly relates to a device for alerting the device user and others of the presence of an unwanted environmental agent.
First responders, such as fire fighters, police, or HAZMAT personnel, many times arrive at the site of an emergency situation without the ability to detect environmental hazards such as toxic industrial chemicals, chemical warfare agents, or radiation. Such inability may result in physical harm to the first responders and other responders that follow. Large quantities of toxic industrial chemicals may be present ‘normally’ in populated areas: industrial sites, storage depots; transportation and distribution facilities, resulting in the potential for accidents such as the accidental release of methylisocyanate in Bhopal, India in 1984. Other toxic industrial chemicals, for example, include ammonia, chlorine, hydrogen chloride, and sulfuric acid. Chemical warfare agents are usually more lethal than toxic industrial chemicals. Nerve agents are the most common chemical warfare agents, such as the nerve agent Sarin that was used in the 1995 Tokyo subway gas attack. Other chemical warfare agents, for example, include Tabun, sulfur mustard, and hydrogen cyanide.
Chemical warfare agents typically are medium to high volatility and therefore may be detected in the gas phase. Electronic monitors for chemical warfare agents are based on electronic detection using ion-mobility-spectrometry, photo-ionization, and flame-ionization. These tools offer a broadband response with high levels of sensitivity, but most suffer from interference effects caused by what is often a highly complex chemical background mix at the scene, and most commercial tools exhibit high false-positive responses to contaminants. Furthermore, these devices are not designed to be wearable, and most tools, although handheld, are relatively bulky and fully engage the user detracting from other important duties.
Known colorimetric methods for detecting such chemical and biological hazards include simple color-change badges generally have a limited life span, e.g., 8 hours, to tubes providing quantitative data with high specificity, but both require the user to assess the color change to determine the hazard level. Furthermore, gas tubes are sensitive to physical abuse and are limited in some cases to only one and in other cases only a few hazards requiring the user to know what type or types of hazards are suspected.
Radiological threats have become more relevant with the so-called ‘dirty bomb’, which combines explosive blast with surreptitious ‘ingredients’ of radionuclides such as Cs-137, a beta and gamma emitter. Radiological monitors (dosimeters) have been available for many years, mostly for occupational safety monitoring.
Pager style, wearable units, having audio/visual alerts built-in are available for such monitoring. Also, a variety of miniature radiation detectors exist, such as small Geiger-Muller tubes, selective scintillation layers with photo-sensors, and silicon diodes. Probes can be attached to other types of monitors, covering any of the radiation species, but these monitors are at best hand-held, and must be maintained regularly. Recently, colorimetric badges that detect radiation have been developed; however, these require the user to constantly monitor its status.
Accordingly, it is desirable to provide a low cost, low power, miniaturized (wearable), reliable (having fewer negatives and false positives) apparatus for detecting the presence of environmental agents and transmitting the results to the user and others without disrupting the user's duties.
An apparatus is provided for detecting an atmospheric component. The apparatus comprises one or more arrays, wherein each array comprises one or more colorimetric reagents. A material encapsulating the colorimetric reagents of each array is capable of being at least partially removed to expose the colorimetric reagents of a selected array to the atmosphere. An imager detects colors of the one or more colorimetric reagents in the selected array. Circuitry then determines changes in colors of the one or more colorimetric reagents within the selected array
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.
Referring to
The colorimetric reagents 16 comprise a thin layer of a chemical that maintains a certain color in ambient air, but changes color when subjected to a specific gaseous agent. Examples of chemicals that could be used as colorimetric reagents include the following:
For the testing for carbon monoxide (CO), the colorimetric reagent 16 comprising K2 Pd (SO3)2 would turn from yellow to black in accordance with the equation:
CO+K2 Pd (SO3)2 yields K2 (SO3)2 Pd CO, where K2 (SO3) Pd CO yields CO2+SO2+Pd+K2SO3.
For the testing for ammonia (NH3), the colorimetric reagent 16 comprising H3PO4 would turn from blue to pink in accordance with the equation:
2NH3+H3PO4 yields (NH4)2 PO4.
For the testing for hydrogen sulfide (H2S), the colorimetric reagent 16 comprising Ag would turn from white-gray to black in accordance with the equation
H2S+Ag yields AgS.
For the testing for organic matter (RCH2OH), the colorimetric reagent 16 comprising KMNO4 would turn from purple to brown in accordance with the equation:
RCH2OH+KMNO4 yields RCOO—K++MNO2+KOH.
Another test for organic matter, the colorimetric reagent 16 comprising Cr2O7 would turn from orange-red to green in accordance with the equation:
RCH2OH+Cr2O7 yields RCHO+Cr3.
For the testing for inorganic matter, such as a Hydrogen Chloride (HCL) mist, the ph indicators Bromophenol blue would change from red to blue, and Mehtylene orange would change from orange to green.
A light source 18 optionally is provided for directing light 20 onto the colorimetric reagents. The light source provides a known spectrum that results in a more reliable determination of the colors of the colorimetric reagents than is provided by ambient light.
The colorimetric reagents 16 are encapsulated in a material 26, e.g., glass, plastic, and low melting-point metals) that may have a portion selectively removed to create an opening 27 by, for example, a heater 28 (see
A heater 30 is positioned so as to prevent the temperature from dropping to an extent that would prevent the chemical reaction in the colorimetric reagents 16 from occurring.
In
Referring to
Referring to
Referring to
One drawback experienced with the use of colorimetric reagents 16 is interference of a second gas in the presence of the unwanted gas that may cause the colorimetric reagents 16 to give a false reading. Referring to
While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.
This application claims the benefit of U.S. Application No. 60/511,488, filed 14 Oct. 2003.
| Number | Date | Country | |
|---|---|---|---|
| 60511488 | Oct 2003 | US |
