Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Means for analyzing liquid or solid sample
Reexamination Certificate
2000-07-14
2003-03-25
Warden, Sr., Robert J. (Department: 1744)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Means for analyzing liquid or solid sample
C422S050000, C422S069000, C422S082050, C422S119000, C422S051000, C252S301160, C252S301350, C252S408100, C252S600000, C524S845000, C524S904000, C524S914000, C524S917000, C524S923000
Reexamination Certificate
active
06537497
ABSTRACT:
BACKGROUND OF THE INVENTION
Arson is a costly public safety problem. The cost of fire damage in the United States is several billions of dollars per year. Arson, the willful and malicious burning of property, accounts for approximately one third of these costs.
The most effective way to try and reduce the cost and damage caused by fire is through the use of effective fire investigation to find and prosecute those responsible. However, the devastation, charred debris, collapsed structures, water-soaked ashes, weather conditions, together with the smoke and stench makes arson extremely difficult to detect and prove.
The basic role of a fire investigator is twofold: first to determine the origin of the fire, and second to examine the site of the fire to determine what caused the fire to start. Once the origin of the fire is found, examination of the debris is necessary to determine the fire's cause. A major objective in any suspected case of arson is to search for, locate, sample and analyze residual accelerants, which are usually in the form of ignitable liquids.
Most purposefully caused fires involve the use of an accelerant to speed the ignition and rate of spread of the fire. The most commonly used accelerants are diesel fuel, mineral spirits, kerosene, gasoline, and turpentine due to their flammability and ready availability. Less commonly used accelerants include alcohols, ketones, and industrial solvents. The amount of accelerant remaining after a fire depends not only on factors such as quantity and type of compound used, but also on the nature of material it is poured on, the elapsed time since the fire, and the severity of the fire.
There are currently several methods for detecting accelerants available. First, physical indicators, such as localized burn patterns to floors and surfaces and overhead damage inconsistent with the naturally available fuel, can be used to detect the presence of accelerants. The primary problem with physical indicators is that they are frequently destroyed during the course of the fire. Further, physical evidence which indicates a hot and intense fire, such as a color change or spalling in concrete, melted aluminum or brass and deformation of steel, are unreliable as indicators of the presence of an accelerant, as many combustible materials tend to burn with the same intensity as accelerants.
Fire investigators often rely upon their own sense of smell to attempt to identify the presence of accelerants. As would be expected, this ability varies greatly amongst investigators since, like most other senses, it can become highly developed through experience, or permanently impaired. In addition, continual smelling of the toxic vapors produced by accelerants cause the sense of smell to become less effective, and lessens the ability of the investigator to discriminate between accelerant vapors.
Sniffer dogs are also used for the detection of accelerants. Dogs have a keener sense of smell than humans, and also have much greater ability to discriminate between target scents. However, the effectiveness of sniffer dogs is entirely dependent on the level of training the dog has been given. Moreover, dogs are sometimes unable to detect odorless fire accelerants, because the accelerant molecule is not aromatic.
Portable hydrocarbon detectors are commonly used in accelerant detection at fire scenes. Hydrocarbon detectors are extremely sensitive and able to separate and detect trace amounts of volatile hydrocarbons. The extreme sensitivity of a hydrocarbon detector is also its biggest drawback, however, since it is associated with a large number of false positives. For instance, a portable hydrocarbon detector can detect hydrocarbons from various materials such as rubber-backed carpet, carpet and tile glue, or burnt plastic, and the results are wrongly interpreted as indicating the presence of an ignitable liquid used as an accelerant.
It is therefore an object of the present invention to provide a more accurate method and means of detecting arson by detecting the presence of ignitable liquids.
It is a further object of the present invention to provide a method and means of absorbing crude oil, petroleum distillates, and solvents to prevent absorption of these substances into the environment.
It is yet another object of the present invention to provide a method and means of detecting and/or absorbing ignitable liquids which is sensitive, yet does not result in a high incidence of false positives.
It is another object of the present invention to provide a method and means of detecting and/or absorbing ignitable liquids which does not rely on the subjective nature of a person or animal's sense of smell.
It is still another object of the present invention to provide a method and means of detecting and/or absorbing ignitable liquids which is economical and easy to use.
Other objects of the invention will become apparent from the description of the invention which follows.
SUMMARY OF THE INVENTION
The present invention relates to the use of a chemical composition for detecting and/or absorbing ignitable liquids using an ignitable liquid absorbent (ILA). The ILA includes a hydrophobic polymer as a primary absorbent and a hydrophobic long-chain carboxylic acid. The ILA may also contain a hydrophobic solvent indicator dye and a hydrophobic white metallic oxide.
The ILA may be applied to an area suspected of containing an ignitable liquid. If the ILA comes in contact with an ignitable liquid, it changes in form from a powder to an aggregate by means of agglomeration. If a hydrophobic solvent indicator dye is included in the ILA, the aggregate also changes color, thereby more precisely indicating the location of an ignitable liquid. Evidence samples taken using the absorbent can then be tested using conventional laboratory procedures, such as gas chromatography or mass spectroscopy to determine the presence of target liquid accelerants or ignitable liquids.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is based on an improved method and means for detecting ignitable liquids.
Through education, training, and experience, fire investigators are able to investigate a fire scene and, based on burn patterns and other evidence collected from the scene, form an expert opinion as to the origin and cause of the fire. However, on many fire scenes where the fire has been intentionally ignited, the use of an ignitable liquid as a fire accelerant is not always obvious, because it remains only in trace amounts after the fire. The remaining trace amounts of ignitable liquid may also be semi- or fully soluble in water, thereby becoming even further diluted as a result of fire suppression efforts prior to the investigation.
Using the composition of the present invention, even trace amounts of the ignitable liquid used to accelerate the fire can be identified and collected as evidence. Further, fuels that are soluble in water can be separated from the water, identified, and collected as evidence.
The first ingredient in the ignitable liquid absorbent (ILA) of this invention is a hydrophobic polymer powder or micro-fiber. Polymers which meet this definition are capable of absorbing or adsorbing ignitable liquids, such as alcohols, ketones, crude oil, petroleum distillates, or solvents. Ignitable liquids are typically nonpolar, or have limited polarity so as not to strongly hydrogen bond with water molecules. Because the water molecule is highly polar, the majority of ignitable liquids will not form a homogenous solution with water, but will instead form an identifiable two-phase liquid separation. Some ignitable liquids, such as specific alcohols or ketones with the lowest molecular weight of their class, will form a homogenous solution when introduced in water. The ILA of this invention has the capability of absorbing these liquids without absorbing a significant amount of water, thus causing their separation from water.
Hydrophobic polymers for use in this invention are generally composed of long linear carbon chains or cross-linked carbon chains and may have a
Chorbaji Monzer R.
McKee Voorhees & Sease, P.L.C.
Warden, Sr. Robert J.
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