Re --the walk thru version--
WAKEFIELD, Mass.--(BUSINESS WIRE)--May 17, 2005--Implant Sciences Corporation (AMEX: "IMX", "IMX.WS") a developer and manufacturer of products for national security, medicine and industry, today announced the issuance of its fourth patent in the field of trace explosives detection technology. US Patent 6,888,128, entitled "Virtual Wall Gas Sampling for an Ion Mobility Spectrometer" covers a special form of gas sampling vortex in which a very large space is enclosed by the spinning air. In particular, this space can be the size of a person and thus be used for testing people in an explosives detection portal. The surrounding vortex flow can readily be penetrated as a person walks inside, yet the inside air is isolated from the outside without the need for solid walls or doors. This isolation persists even in the presence of a wind, which could permit the use of a passenger portal in the outdoors, such as s stadium entrance, or near air conditioning systems.
biz.yahoo.com
RE USP 6,888,128
patft.uspto.gov
See Figs. 6, 7 and 8:
FIG. 6 illustrates an alternative embodiment of a gas sampler that may be used with the ion mobility spectrometer of FIG. 1 or may be used with other systems that sample gas. FIG. 6 shows an axial view of a virtual wall sheet-like airflow 111 disposed tangential to the enclosed sample volume 116. The normal axis of flow of the sheet-like airflow 111 is disposed substantially perpendicular to the axis of the external sampling orifice 20 (not shown in this view) of the ion mobility spectrometer. FIG. 6 shows an example of four such sheet-like airflows 111, which together form the circumferential walls of a box-like volume. Each sheet-like airflow 111 is provided by a sheet-like air flow source 110, such as an air knife. The source 110 is illustrated as consisting of a manifold emptied through a narrow slit aperture followed by a curved surface employing provide the Coanda effect. Of course, other mechanisms may be used as sources, such as different types of nozzles, air knives, air curtain generators, air doors, other devices that provide the Coanda effect, deflection vanes, and other appropriate devices. In addition, any number of sources may be used to provide the system described herein. For example, two air knives disposed on opposing sides combined with two solid surfaces disposed on the perpendicular axis to form four sides of a box would provide entrance and exit air doors for a gas sampling volume.
A sheet-like flow may be defined as originating from one or more sources whose combined aperture is substantially greater on one axis compared to the perpendicular axis and whose half-maximum flow divergence angle on the substantially smaller axis is less than 25 degrees at a distance of 30 centimeters from the source. A sheet-like flow may be straight or curved on the longer axis. An air knife may be provided by a manifold for pressurized air with an exit nozzle in which one axis is substantially smaller than the perpendicular axis. For example, an air knife may have a nozzle aperture that is tens of centimeters by 0.05 centimeters. An air knife may be straight or curved on the larger axis. An air knife may be combined with various means to deflect the air flow, such as a nozzle, a surface employing the Coanda effect, or deflection vanes. An air door or air curtain may be provided by a plurality of closely spaced nozzles disposed along a line, such that the combined aperture of the array may be a few centimeters by many tens of centimeters. The Coanda effect is the tendency of a thin sheet-like air flow to follow the contour of a one-sided bounding surface until a discontinuity is encountered.
The sheet-like air flow may form at least one bounding surface for a gas sampling volume. In embodiments disclosed herein, the sheet-like air flow does not intentionally impact or wipe any target objects within the gas sampling volume. The sheet-like air flow may provide a barrier separating the external atmosphere from the internal gas sampling volume, which is at a lower pressure than the external atmosphere. A heater (not shown) that heats the sheet-like air flow may be optionally included. Other means for adding ions may also be used. The heater or other means for adding ions may be provided by an appropriate device or technique familiar to one of ordinary skill in the art. Heating the sheet-like air flow may cause increased target vapor emission. Ions may be used to assist in the release of particles from target surfaces.
The directions of flow are illustrated in FIG. 6 as inducing a clockwise circulation, which creates a vortex. The vacuum pump 14 of the ion mobility spectrometer causes a flow of the sampled gas 12 to enter into the external sampling orifice 20 (not shown in this view). The enclosed sample volume 116 is bounded by the sheet-like airflows 111, as seen in this view.
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I fervently hope that HISC has the rights to sell this walk thru version - it's where the need is, and, as a result, the money is. |
