High volume sampling front end collection device
Inventors
Assignees
US Department of Homeland Security
Publication Number
US-8578796-B2
Publication Date
2013-11-12
Expiration Date
2031-06-09
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Abstract
A device for sampling surfaces for the presence of compounds is provided, including a housing having a proximal end adapted to receive it negative pressure gradient and a distal end adapted to contact the surfaces; a heating element spaced from the distal end; a primary filter spaced from the heating element; and a secondary filter spaced from the primary filter, the secondary filter removably received by the housing. Also provided is as method for sampling a surface for the presence of compounds, the method including contacting the surface to dislodge the compounds from the surface; capturing first fractions of the compounds with a primary filter while allowing second fractions of the compounds to pass through the primary filter; heating the primary filter to volatilize the first fractions; capturing the volatized first fractions and the second fractions with a secondary filter; and analyzing the secondary filter to identify the compounds.
Core Innovation
The invention provides a device for sampling surfaces for the presence of compounds, designed for efficient and rapid collection of solid particles and vapor phase compounds from various surfaces including sea cargo containers, pelletized cargo, and smaller items such as shoe soles. The device comprises a housing with a proximal end adapted to receive a negative pressure gradient and a distal end adapted to contact the surfaces. Inside the housing, the device includes a heating element spaced from the distal end, a primary filter downstream from the heating element that captures large particles including target compounds and unwanted dirt or dust, and a secondary filter positioned downstream from the primary filter which is removably received by the housing and traps vaporized compounds for eventual analysis.
The device addresses the need for a portable, lightweight, and low-cost high volume sampling system capable of simultaneous sequestration of multi-phase target compounds. It overcomes disadvantages of existing sampling devices such as inefficiency in high volume sampling, large operational footprints, operator movement hindrance from tethered wands, one-time use of swabs, and limitations in collecting vapor and solid or liquid phase samples simultaneously. The invention allows in situ replacement of sample sequestration carriers to enable continued sampling without interruption and adapts to conventional detection systems and analytical machinery.
The device features a reversible adsorption process in the secondary filter that stabilizes adsorbed compounds for hours to days depending on the resin and compound chemistry. It provides dual filtering stages with a heating element that vaporizes compounds trapped on the primary filter, which are then re-trapped in the secondary filter for pre-concentration and analysis. The system supports both contact and non-contact sampling methods, adaptable with removable brushes or cones, enabling use in various sampling scenarios while maintaining portability and low cost through use of off-the-shelf vacuum and sampling components.
Claims Coverage
The patent includes two independent claims that define the main inventive features of the sampling device and its functional configuration.
Multi-stage sampling device with vaporization and capture capabilities
The device comprises a housing with a proximal end adapted for a negative pressure gradient and a distal end adapted to contact surfaces. It includes a heating element spaced from the distal end within the housing, a primary filter downstream from the heating element that collects particles, and a secondary filter downstream from the primary filter that is removably received by the housing. Upon heating the primary filter, collected particles are vaporized and these vapors are collected by the secondary filter for analysis.
Sampling device housing and filtration arrangement with fluid communication
The device has a housing with a proximal end adapted to receive a negative pressure gradient and a distal end adapted to receive solid and gaseous phase moieties. A heating element is positioned within the housing spaced from the distal end. The primary filter is downstream of the heating element and encased by the housing, adapted to capture solid moieties and vaporize them when heated. The secondary filter is downstream of both the heating element and primary filter, removably received by the housing, and adapted to capture gaseous phase moieties passing through the primary filter and vaporized moieties from the primary filter. Activation of the heating element provides negative pressure downstream through the housing from the primary filter to the secondary filter.
Together, these inventive features define a portable high volume sampling device with a two-stage filtration system including an integrated heating element that vaporizes particulate matter collected on the primary filter, allowing capture on a removable secondary filter for direct analysis, enabling efficient collection and analysis of solid and vapor phase compounds from sampled surfaces.
Stated Advantages
Efficient and rapid collection of particles and vapors simultaneously on the same sample sequestration carrier.
Portability with a device transportable within a shirt pocket, enabling in-field sampling and carrying.
Capability to hold trapped vapor compounds for durations ranging from an hour to several days, depending on resin choice and sample chemistry.
Interchangeable sample sequestration carriers allow continuous sampling without interruption by replacing full carriers with empty ones in situ.
Adaptability to both contact and non-contact sampling modes through removable attachments like brushes or cones.
Low cost, light weight, and small size relative to state-of-the-art systems due to compatibility with off-the-shelf vacuum systems and analytical instrumentation.
Provides a completely dry compound detection system using reversible adsorption to maintain compound stability during transport for analysis.
Documented Applications
Sampling surfaces of sea cargo containers, pelletized cargo, and smaller items such as shoe soles for target compounds.
Screening of explosives, chemical and biological warfare agents, industrial toxic chemicals, drugs, and hazardous waste.
High volume air sampling in cargo environments including break bulk, pelletized, or containerized air/sea cargo.
Use in security screening scenarios such as TSA checked bag screening, TSA checkpoint passenger screening, and Person Borne Improvised Explosive Device (PBIED) detection.
Adaptation for use with conventional detection and analytic systems such as Smiths Detection 500DT, Morpho Detection ETD systems, and Smiths Ionscan 400B and 500DT detectors.
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