Gas separation – With recycle means – For concentrate entrained in effluent gas outlet means
Reexamination Certificate
2002-04-23
2004-09-14
Hopkins, Robert A. (Department: 1724)
Gas separation
With recycle means
For concentrate entrained in effluent gas outlet means
C055S385200, C055S467000, C055SDIG003, C096S413000, C096S417000, C454S187000, C454S230000, C073S023200
Reexamination Certificate
active
06790249
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to both an apparatus for and method of screening people and articles to detect exposure and/or to decontaminate with respect to toxic materials, such as condensible gases and vapours and liquid or solid particles originating from industrial accidents or chemical warfare.
BACKGROUND OF THE INVENTION
Rapid screening techniques are required to quickly identify people who may have been exposed to toxic emissions, notably either from chemical warfare gases and vapours or chemicals spilled or accidentally formed from industrial accidents. Often these substances are released or disseminated in liquid form, and the liquids have effectively low boiling points such that the vapours are readily emitted.
Following a chemical warfare agent attack, for example, numerous people could be contaminated, as, for example, in crowded metropolitan underground rail systems. Since nerve and chemical warfare agents are extremely toxic, quick response and remedial action is essential. If liquid agents were disseminated into closed areas, the contamination could be very high. Great care must therefore be taken to ensure that in a mixed population of victims or potential victims, those who are contaminated are quickly separated from those who are not.
In the Tokyo Metropolitan Rail attack, sarin was used and the First Responders (i.e., emergency personnel such as Fire, Police or ambulance staff, who first arrived at the scene) were unable to separate contaminated from uncontaminated people. As a consequence, victims whose clothing had been contaminated with the sarin became sources of reliberation of the vapours, which then cross-contaminated people who were originally unaffected. Thus, the casualties from the attack were greatly multiplied.
It is most desirable, therefore, to develop a quick screening system where individuals could pass through a walk-through portal, similar to Walk-Through Metal Detectors (WTMD) used in airports for screening passengers for concealed weapons. Just as WTMD systems detect the presence of metal objects, the inventor has realized that a similar screening system could be used to detect the presence of chemical agents. There is a need for easily deployed walk-through portal systems provided with air jets that can air brush people and speedily process possible victims on a walk-through basis.
Linker et al in U.S. Pat No. 5,915,268, Settles in U.S. Pat. No. 6,073,499, Arney et al in U.S. Pat. No. 4,896,547 and Corrigan et al. in U.S. Pat. No. 4,987,767, teach that a curtain using flowing air, or other gas, can quickly thermally desorb high vapour pressure materials from the skin and/or clothing of persons, and, further, that such air curtains can be integrated into portals which can be used to screen persons for the presence of a wide variety of materials, most commonly explosives and drugs of abuse. The present invention provides improvements to prior art portals to extend their use to the triage and decontamination of persons who, as the result of chemical warfare, terrorist attack, or industrial or transportation accident, may have been exposed to toxic substances which have become attached to their skin and clothes, thereby prolonging their exposure and increasing the probability of serious injury.
SUMMARY OF THE INVENTION
A walk-through portal can include a plenum which can deliver a high volume flow of warm air over the person being processed. The person walks into the portal and executes a 90′ turn so that the air jets, preferably heated, can blow over the front and back areas of their body. Typically, the person remains in the examination zone for about 12 seconds, and is swept by about 2,000 L of air. An exhaust system collects the warm air into a plenum containing a filter. Any chemical on skin or clothing is liberated and passes as either particles, droplets or vapour into the plenum for subsequent removal by the filtering system. An analytical instrument such as an ion mobility spectrometer, is used to make chemical measurements on the air flow exhausted through the plenum prior to filtering. However, many other techniques exist. An enrichment process can allow agents to be removed from the high volume air flow so as to be transferred into a much lower air flow compatible with instruments such as an IMS detector. Other instruments can be used to monitor the effluent such as fast gas chromatographs, IR analyzers, electrochemical cells and other such devices according to their analytical capabilities and speed of response for the analytes of interest. Shutting off the main air flow and heating the filter in a much lower air flow can provide an enrichment process and allow agents to be detected at lower levels. Such devices can be provided in a portable form such that they may be readily transported from site to site and quickly reassembled where chemical terrorism acts or industrial accidents may have occurred. Alternatively such portals can be permanently installed at critical sites. Such a portal can also be optimized for detection of contraband substances.
In actual operation, especially where large numbers of individuals may need to be processed, speed is of essence and a number of such prescreening warm air only portals could be provided. The preliminary processing involves basic air decontamination; the individuals could be subsequently screened through a second portal which incorporates the chemical measurement means to check if decontamination was successful. Where the number of victims are few, a single portal can perform the functions of decontamination and contamination monitoring.
The portals could be constructed as portable devices or “knock-down” kits, allowing for ease of transport and rapid assembly at the site of the chemical release. Evidently, such portals could be permanently constructed for us in chemical plants or military installations where dangerous chemical materials are stored, handled, processed or positioned. Additionally, such portals could be used as security screens at airport check points.
In accordance with a first aspect of the present invention, there is provided a walk-through portal for at least one of detection of a predetermined substance on a subject and decontamination of a subject from a predetermined substance, the walk-through portal comprising:
an enclosure defining an examination zone and being substantially open on at least one side, to permit a subject readily to enter and to exit the examination zone;
a closure means for substantially closing off the examination zone from the exterior;
an inlet into the examination zone and an outlet from the examination zone; and
a pump for pumping a gas through the inlet into the examination zone, over a subject to entrain at least one of vapours, and particulates from such substance, and out through the outlet.
The portal preferably includes at least one flexible screen, closing off the examination zone. More preferably, the walk-through portal is open on opposite sides thereof, to enable a subject to walk into the examination zone from one side and out from the examination through the other side, and the walk-through portal further includes flexible screens on both sides, closing off the examination zone.
Advantageously, the portal includes an output decontamination filter connected to the outlet from the examination zone, for ensuring that gas exhausted into the atmosphere is free from any contaminating substance and/or an inlet filter, mounted between the inlet and the examination zone, for filtering gas flowing into the examination zone.
Preferably, the walk-through portal includes an analyzer, connected to the outlet, for taking a sample of gas flowing through the outlet, whereby the analyzer determines the presence of said substance in the gas flowing through the outlet and/or a detection instrument connected to the inlet, for monitoring gas flowing into the examination zone for presence of contamination.
Instead of an open system, the portal can include a recirculation duct connected between the outlet and the inlet and a
Bereskin & Parr
Hopkins Robert A.
Smiths Detection-Toronto Ltd.
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