WO2015198272A1 - Apparatus for sampling chemical substances, and methods therefor - Google Patents

Apparatus for sampling chemical substances, and methods therefor Download PDF

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Publication number
WO2015198272A1
WO2015198272A1 PCT/IB2015/054802 IB2015054802W WO2015198272A1 WO 2015198272 A1 WO2015198272 A1 WO 2015198272A1 IB 2015054802 W IB2015054802 W IB 2015054802W WO 2015198272 A1 WO2015198272 A1 WO 2015198272A1
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WO
WIPO (PCT)
Prior art keywords
sorbent
container
gas
adsorption
arrangement
Prior art date
Application number
PCT/IB2015/054802
Other languages
French (fr)
Inventor
Vladimir Alperovitch
Original Assignee
B.S. Ma'avarim Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB1411326.0A external-priority patent/GB2527558A/en
Priority claimed from GB1411328.6A external-priority patent/GB2527559A/en
Application filed by B.S. Ma'avarim Ltd filed Critical B.S. Ma'avarim Ltd
Publication of WO2015198272A1 publication Critical patent/WO2015198272A1/en

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/02Devices for withdrawing samples
    • G01N1/22Devices for withdrawing samples in the gaseous state
    • G01N1/2202Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
    • G01N1/2214Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling by sorption
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/02Devices for withdrawing samples
    • G01N1/22Devices for withdrawing samples in the gaseous state
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/28Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
    • G01N1/40Concentrating samples
    • G01N1/405Concentrating samples by adsorption or absorption
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/02Devices for withdrawing samples
    • G01N1/22Devices for withdrawing samples in the gaseous state
    • G01N1/2226Sampling from a closed space, e.g. food package, head space
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/02Devices for withdrawing samples
    • G01N2001/022Devices for withdrawing samples sampling for security purposes, e.g. contraband, warfare agents
    • G01N2001/024Devices for withdrawing samples sampling for security purposes, e.g. contraband, warfare agents passengers or luggage
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00Sampling; Preparing specimens for investigation
    • G01N1/02Devices for withdrawing samples
    • G01N1/22Devices for withdrawing samples in the gaseous state
    • G01N1/2226Sampling from a closed space, e.g. food package, head space
    • G01N2001/2241Sampling from a closed space, e.g. food package, head space purpose-built sampling enclosure for emissions

Definitions

  • the present invention relates to apparatus for sampling chemical substances, and methods therefor.
  • an apparatus for sampling and processing at least one hazardous substance within a target volume including: a container having the target volume disposed therein; an adsorption arrangement, including a first sorbent having a first adsorption surface and at least a second sorbent having at least a second adsorption surface, the first and second adsorption surfaces being adapted to adsorb gas-phase molecules; a desorption arrangement functionally associated with the first sorbent and adapted to effect desorption of gas-phase molecules adsorbed onto the first adsorption surface; and a fluid transfer arrangement adapted and disposed to: withdraw a first gas sample from within the container during a withdrawal mode; deliver the gas sample to the first adsorption surface, during a first sampling mode; and, subsequently, deliver to the second adsorption surface, during a second sampling mode, a second gas sample containing gas phase molecules desorbed from the first adsorption surface.
  • an apparatus for sampling and processing at least one target substance within a target volume including: (a) a container having the target volume disposed therein; (b) an adsorption arrangement, including a first adsorption stage and a second adsorption stage, the first adsorption stage having a first adsorption surface, the second adsorption stage including at least a second adsorption stage sorbent having at least a second adsorption surface, the first and second adsorption surfaces being adapted or selected to adsorb gas- phase molecules; (c) a desorption arrangement functionally associated with the first adsorption stage and adapted to effect desorption of gas-phase molecules adsorbed onto the first adsorption surface; and (d) a fluid transfer arrangement adapted and configured to: (i) withdraw a first gas sample from within the container during a withdrawal mode; (ii) deliver the first gas sample to the first adsorption surface, during a first sampling mode; and,
  • a method of the sampling and processing of the at least one hazardous substance disposed within the target volume including: sampling the container to produce the first gas sample; contacting the first gas sample with the first adsorption surface to produce a first loaded sorbent; subsequently desorbing material adsorbed to the first adsorption surface to produce the second gas sample containing the gas phase molecules; and contacting the second gas sample, with the second adsorption surface, to produce at least a second loaded sorbent.
  • an apparatus for sampling and processing at least one hazardous substance within a target volume including: a container having the target volume disposed therein; an adsorption arrangement, including at least one sorbent having an adsorption surface adapted to adsorb gas-phase molecules, and a sorbent housing, the sorbent disposed within the housing; a fluid transfer arrangement, adapted and disposed to: withdraw gas from within the container during a gas withdrawal mode; and deliver the gas to the adsorption surface, during a sampling mode; the adsorption surface having a characteristic pore diameter of at least 65 micrometers ( ⁇ ).
  • a method of the sampling and processing of the at least one hazardous substance within the container or target volume including: sampling the container or target volume to produce a target volume sample; and contacting the sample with the adsorption surface to produce a loaded sorbent.
  • the container has minimum dimensions of 0.5 meters by 0.5 meters by 0.5 meters.
  • At least one of the first and second adsorption surfaces have a characteristic pore diameter of at least 65 ⁇ , at least 75 ⁇ , at least 85 ⁇ , at least 100 ⁇ , at least 125 ⁇ , at least 150 ⁇ , at least 200 ⁇ , or at least 300 ⁇ .
  • the characteristic pore diameter is at most 3500 ⁇ , at most 2000 ⁇ , at most 1200 ⁇ , at most ⁇ , at most 900 ⁇ , at most 750 ⁇ , at most 650 ⁇ , or at most 550 ⁇ .
  • the characteristic pore diameter is within a range of 70 to 1500 ⁇ , 80 to 1500 ⁇ , 100 to 1200 ⁇ , 100 to 1000 ⁇ , 150 to 1200 ⁇ , 200 to 1200 ⁇ , 200 to 1000 ⁇ , 250 to 1200 ⁇ , 300 to 1200 ⁇ , 300 to 1000 ⁇ , 350 to 1000 ⁇ , 350 to 800 ⁇ , or 400 to 1000 ⁇ .
  • At least one of the first and second sorbents is temperature stable at a lower temperature limit of 0°C and up to an upper temperature limit of at least 70°C.
  • the upper temperature limit is 85°C, 95°C, 110°C, 130°C, 150°C, 175°C, or 200°C.
  • the apparatus further includes a heating arrangement, adapted to heat the target volume.
  • the heating arrangement includes a recirculation loop attached to the container to form an outlet for withdrawing the gas from the container, and an inlet for returning the gas to the container; a recirculation pump, fluidly associated with the loop, and adapted to effect forced circulation of the gas by withdrawing the gas via the outlet and returning the gas to the container via the inlet; and a heating arrangement, associated with the loop, and adapted to heat the gas as the gas transits the recirculation loop.
  • the recirculation pump and heating arrangement are controlled such that the gas reintroduced to the container via the inlet has a temperature that exceeds a bulk temperature within the container by at most 40°C, at most 35°C, at most 30°C, at most 25 °C, at most 20°C, at most 15°C, or at most 10°C.
  • the container is sealed, during the gas withdrawal mode, from an ambient environment.
  • the apparatus further includes a pumping arrangement, fluidly associated with the container, and adapted to introduce an external gas to the container.
  • the pumping arrangement is adapted and positioned such that the external gas includes, or consists essentially of, ambient air.
  • At least one of the first and second sorbents has a specific surface area within a range of 0.1 to 50 m 2 /gram.
  • any filtration arrangement for filtering the gas from within the container is disposed downstream of the adsorption arrangement, so as to receive a portion of the gas after the portion has been discharged from the adsorption arrangement.
  • At least one of a first gas flow path between the container and the first sorbent, and a second gas flow path between the first and second sorbents, or both flow paths, are free of any gas filtration arrangement.
  • the apparatus further includes a ventilating arrangement having a ventilator disposed within the container, and adapted, in a ventilation mode, to mix the gas within the container.
  • the container is semi-rigid, at least semi-rigid, or rigid.
  • the apparatus further includes a controller, configured to control the fluid transfer arrangement.
  • the controller is configured to control the fluid transfer arrangement to periodically attain a sub-atmospheric pressure within the container, during a single sampling run.
  • the controller is configured to control the fluid transfer arrangement to periodically attain a super-atmospheric pressure within the container, during a single sampling run.
  • the controller is configured to control the fluid transfer arrangement to periodically attain, within the container, a sub-atmospheric pressure, and a super-atmospheric pressure, during a single sampling run.
  • the controller is further configured to maintain a maximum pressure within the container below 1.5 atmosphere absolute (ata), below 1.4 ata, below 1.3 ata, below 1.25 ata, below 1.2 ata, below 1.15 ata, or below 1.1 ata.
  • the controller is further configured to control the fluid transfer arrangement to effect at least one operating cycle within a sampling run, wherein, in each cycle of the at least one operating cycle, the container undergoes pressurization from a sub-atmospheric pressure state to a super-atmospheric pressure state.
  • the super-atmospheric pressure state includes a peak pressure state
  • the sub-atmospheric pressure includes a peak vacuum state
  • the controller further configured to control the fluid transfer arrangement such that the pressurization from the peak vacuum state to the peak pressure state, or vice versa, within a single cycle of the operating cycle, is achieved over a period of at least 1 second, at least 2 seconds, at least 5 seconds, at least 10 seconds, or at least 20 seconds.
  • the super-atmospheric pressure state includes a peak pressure state
  • the sub-atmospheric pressure includes a peak vacuum state
  • the controller further configured to control the fluid transfer arrangement such that a transient pressure gradient (dP/dt) within the container is maintained below 1,000 Pa/s, or within a range of 100 to 1,000 Pa/s, 150 to 1,000 Pa/s, 200 to 1,000 Pa/s, 300 to 1,000 Pa/s, 400 to 1,000 Pa/s, or 200 to 800 Pa/s, within at least one cycle of the operating cycle.
  • dP/dt transient pressure gradient
  • the controller is further configured to control the fluid transfer arrangement such that a first volume of the first gas sample delivered by the fluid transfer arrangement to the first sorbent is larger than a second volume of the second gas sample delivered by the fluid transfer arrangement from the first sorbent to the second sorbent, a dimensionless volumetric ratio between the first volume and the second volume being at least 2, at least 4, at least 8, at least 20, at least 50, at least 100, at least 250, at least 500, or at least 1000.
  • the container has a total volume Vc
  • the controller being further configured to control the fluid transfer arrangement such that a dimensionless volumetric ratio of a sampling volume (Vs) of the first gas sample to the first sorbent, to the total volume (Vc), is at least 0.1, at least 0.2, at least 0.3, at least 0.5, at least 1, at least 2, at least 3, at least 4, or at least 5.
  • the volumetric ratio (Vs/Vc) is at most 10, at most 8, at most 7, or at most 6.
  • the controller is further configured to initiate a sterilization mode within the apparatus, following the sampling mode.
  • the sterilization mode including heating an internal volume of the container, using at least one heating arrangement, to at least 70°C, at least 85°C, at least 100°C at least 150°C, at least 200°C, at least 250°C, or at least 300°C.
  • At least one of the first and second sorbents includes, largely (more than 50% of the surface area) includes, or consists essentially of a sorbent fabric.
  • the sorbent fabric includes, largely includes, or consists essentially of a material selected from the group consisting of rayon fiber and fiberglass.
  • the first sorbent includes, largely includes, or consists essentially of sorbent granules.
  • the adsorption arrangement includes a first sorbent housing having the first sorbent disposed therein and including a sealed chamber having at least a first port and a second port, the ports fluidly intercommunicating via the chamber, and via the first sorbent.
  • At least one of the first and second sorbents includes the sorbent fabric, a compressive strength of the sorbent fabric being at most 3MPa, at most l .OMPa, at most 0.5MPa, at most 0.3MPa, at most 0.2MPa, at most 0. IMPa, at most 0.05MPa, or at most 0.02MPa.
  • At least one of the first and second sorbents includes the sorbent granules, a compressive strength of the sorbent granules being at most lOMPa, at most 5MPa, at most 2MPa, at most IMPa, at most 0.5MPa, at most 0.2MPa, at most 0. IMPa, or at most 0.05MPa.
  • the apparatus further includes a detection arrangement adapted to receive the second sorbent.
  • the method further includes exposing at least one of the first and second loaded sorbents to deliver vapor to a biosensor.
  • the biosensor is a sniffing dog.
  • the method further includes disposing the biosensor within one meter of at least one of the first loaded sorbent and the second loaded sorbent.
  • the method further includes delivering the second loaded sorbent to deliver vapor to an instrumental chemical detection system.
  • the maximum pressure differential across the first adsorption surface, during the contacting of the sample therewith is less than 1,000 Pa, less than 800 Pa, less than 600 Pa, less than 500 Pa, less than 400 Pa, less than 300 Pa, less than 200 Pa, less than 150 Pa, or less than 100 Pa.
  • the sampling of the container to produce the first gas sample is effected within 3 minutes, within 2.5 minutes, within 2 minutes, within 1.5 minutes, or within 1 minute, while maintaining a maximum pressure differential across the first adsorption surface, during the contacting of the sample therewith, below 1,000 Pa, below 800 Pa, below 600 Pa, below 500 Pa, below 400 Pa, below 300 Pa, below 200 Pa, below 150 Pa, or below 100 Pa.
  • the first gas sample has a volume of at least 0.1m 3 , at least 0.2m 3 , at least 0.3m 3 , at least
  • the method further includes, subsequent to step (e), heating the container to at least at least 70°C, at least 85 °C, at least 100°C at least 150°C, at least 200°C, at least 250°C, or at least 300°C, so as to desorb or otherwise remove any of the at least one hazardous substance disposed within the container.
  • the hazardous substance includes at least one of trinitrotoluene (TNT) and an explosive nitramine compound.
  • the desorbing of material adsorbed to the first adsorption surface is performed in at least first and second time periods, the second time period being subsequent to the first time period, wherein, in the first time period, the desorbing is effected at a first temperature, and in the second time period, the desorbing is effected at a second temperature, and wherein the second temperature exceeds the first temperature.
  • At least a fraction of the gas desorbed during the first time period is diverted from contacting the second adsorption surface.
  • the second sorbent includes a first sorbent unit and a second sorbent unit, and at least a fraction of gas desorbed during the first time period is contacted with the second adsorption surface of the first sorbent unit, and at least a fraction of gas desorbed during the second time period is contacted with the second adsorption surface of the second sorbent unit.
  • the second sorbent includes a first sorbent unit and a second sorbent unit, and at least a fraction of gas desorbed during the first time period is contacted with the second adsorption surface of the first sorbent unit, and at least a fraction of gas desorbed during the second time period is contacted with the second adsorption surface of the second sorbent unit, so as to improve chemical selectivity or reduce a concentration of masking agents in the second sorbent unit.
  • the sorbent material includes, or consists of, a fabric sorbent.
  • the sorbent material includes rayon fiber or fiberglass.
  • the compressive strength of the sorbent fabric is at most 3MPa, at most l .OMPa, at most 0.5MPa, at most 0.3MPa, at most 0.2MPa, at most O. lMPa, at most 0.05MPa, or at most 0.02MPa.
  • the sorbent includes, or consists of, sorbent granules.
  • the compressive strength of the sorbent granules is at most lOMPa, at most 5MPa, at most 2MPa, at most IMPa, at most 0.5MPa, at most 0.2MPa, at most O. lMPa, or at most 0.05MPa.
  • a method of sampling and processing at least one hazardous substance within a target volume including any feature described, either individually or in combination with any feature, in any configuration.
  • Figure 1 is a schematic illustration of an embodiment of an apparatus for sampling and processing hazardous substances within a target volume, constructed and operative in accordance with an embodiment of the teachings herein;
  • FIG. 2 is a schematic illustration of a heating arrangement forming part of the apparatus of Figure 1, constructed and operative in accordance with an embodiment of the teachings herein;
  • Figure 3 is a schematic illustration of an embodiment of an adsorption arrangement and a fluid transfer arrangement forming part of the apparatus of Figure 1, constructed and operative in accordance with an embodiment of the teachings herein;
  • Figure 4 is a schematic illustration of a sorbent chamber forming part of the adsorption arrangement of Figure 3 constructed and operative in accordance with the teachings herein;
  • Figures 5A and 5B are images representing the microstructure of two different sorbent materials which may be used in the adsorption arrangement of Figure 3 and the sorbent chamber of Figure 4, wherein Figure 5 A represents a sorbent fabric and Figure 5B represents sorbent granules; and
  • Figures 6A and 6B are schematic representations of exemplary adsorption surfaces used in the adsorption arrangement of Figure 3.
  • Figure 1 is a schematic illustration of an embodiment of an apparatus for sampling and processing hazardous substances within a target volume, constructed and operative in accordance with an embodiment of the teachings herein.
  • an apparatus 100 for sampling and processing at least one target substance typically a hazardous substance, such as explosive substances (e.g., TNT, RDX, HDX) or pesticides, includes a container 102 having a target volume 109 disposed therein.
  • Target volume 109 may contain a stack or pallet of cartons or suitcases, by way of example.
  • Container 102 may have any suitable dimensions. In some embodiments, however, container 102 has a minimum volume of 0.2 cubic meters and minimum dimensions of 0.5 meters by 0.5 meters by 0.5 meters.
  • the target volume of the container is configured to receive at least one object (not shown) to be sampled for the presence of at least one hazardous substance.
  • the objects to be examined may be introduced and removed from container 102 via a door 104.
  • Container 102 and door 104 may be adapted to be sealable from an ambient environment.
  • a ventilator 106 is disposed within container 102 and may be adapted to mix gas present within container 102 prior to and/or during withdrawal of the gas from the container.
  • a pressure sensor or meter 108 is functionally associated with container 102 and is configured to measure the pressure therein.
  • pressure meter 108 is mounted on container 102 at a location visible to a human operator of apparatus 100.
  • adsorption and fluid transfer arrangement 110 Functionally associated with container 102 is an adsorption and fluid transfer arrangement 110, whose components and functionality are described in further detail hereinbelow with reference to Figures 3 - 6B.
  • a heating arrangement 116 is functionally associated with container 102, and may be adapted to heat the gas within container 102, and more specifically, the gas within target volume 109, prior to and/or during withdrawal of the gas from container 102, and/or during sterilization thereof.
  • the components and functionality of heating arrangement 116 are described in further detail hereinbelow with reference to Figure 2.
  • a pumping arrangement 118 such as an overpressure blower, is fluidly associated with container 102 via a valve 120, and is adapted to introduce an external gas, such as ambient air, into container 102, while valve 120 is open, e.g., during a withdrawal mode (or a portion thereof), and typically but not exclusively, in a sampling mode.
  • an external gas such as ambient air
  • a controller (similar or substantially identical to controller 350 shown in Figure 3) is functionally associated with pumping arrangement 118, and may be configured to control fluid flow into and out of container 102, as is described in further detail hereinbelow.
  • FIG. 2 is a schematic illustration of heating arrangement 116 forming part of the apparatus of Figure 1, constructed and operative in accordance with an embodiment of the teachings herein.
  • Heating arrangement 116 may include a recirculation loop 200, attached to container 102 at an outlet 202 for withdrawing gas from container 102 and at an inlet 204 for returning the gas, following heating thereof, to container 102.
  • Flow of gas through outlet 202 may be controlled by an outlet valve 206 and flow of gas through inlet 204 may be controlled by an inlet valve 208, as described in further detail hereinbelow.
  • a recirculation pump or blower 210 is in fluid communication with recirculation loop 200, and is adapted to effect forced circulation of gas from container 102 by withdrawing the gas from container 102 via outlet 202 and returning the heated gas to container 102 via inlet 204.
  • a heating element 212 may be in fluid communication with recirculation loop 200, and may be adapted to heat the gas withdrawn from container 102 as the gas transits recirculation loop 200.
  • a thermostat (not shown) is functionally associated with heating element 212, such that the heating temperature of the gas passing through the heating element 212 can be controlled by a controller 240 (or controller 350 shown in Figure 3) or by an operator of the apparatus 100.
  • a conduit 214 disposed downstream of heating element 212 may include, or be connected to, a recirculation branch 216 adapted to reintroduce heated gas to container 102, via inlet 204.
  • Conduit 214 may be further connected to an exhaust pipe branch 218 associated with a valve 220 and adapted for selectively removing gas from recirculation loop 200, as will be described hereinbelow.
  • recirculation branch 216 has functionally associated therewith a thermocouple port 222, adapted for enabling control of the temperature of gas reintroduced into container 102 via inlet 204.
  • Arrows 224, 226, 228, and 230 indicate the gas flow direction through recirculation loop 200, where arrow 228 indicates reintroduction of gas to container 102 via recirculation branch 216, and arrow 230 indicates removal of gas from recirculation loop 200 via exhaust pipe branch 218.
  • a recirculation and heating controller 240 is functionally associated with recirculation pump 210 and/or with heating element 212, and is adapted to control the volume of gas drawn from container 102, the volume of gas reintroduced into container 102, the temperature to which heating element 212 heats the gas passing therethrough, and/or the orientations (e.g., degree of opening) of valves 206, 208, and 220.
  • Figure 3 is a schematic illustration of an embodiment of an adsorption arrangement and a fluid transfer arrangement forming part of the apparatus of Figure 1, constructed and operative in accordance with an embodiment of the teachings herein.
  • adsorption and fluid transfer arrangement 110 of Figure 1 includes an outlet 302 fluidly associated with container 102 for withdrawal of gas therefrom.
  • An outlet valve 304 is functionally associated with outlet 302, and is configured to close the outlet 302 upon demand, as described in further detail hereinbelow.
  • a sorbent or adsorption chamber 306 is in fluid communication with outlet 302 via valve 304 and a conduit 307.
  • sorbent chamber 306 has a sorbent housing 400 including an inlet port 402 which may be in fluid flow communication with outlet 302 of container 102, and through which gas from container 102 can enter sorbent housing 400.
  • sorbent housing 400 is sealed from the environment. Inside sorbent housing 400 may be disposed a sorbent 406, which may have an adsorption surface adapted to adsorb gas-phase molecules of hazardous substances. Sorbent 406 allows fluid communication between an upper portion 408 of housing 400 above the sorbent 406 and a lower portion 410 of the housing 400 below the sorbent 406
  • sorbent 406 is supported in sorbent housing 400 by a permeable support element or arrangement 412, such as a support net (including multilayer support nets, and multi-layer support nets supported on grids) or a perforated pan or container.
  • a permeable support element or arrangement 412 such as a support net (including multilayer support nets, and multi-layer support nets supported on grids) or a perforated pan or container.
  • a permeable support element or arrangement 412 such as a support net (including multilayer support nets, and multi-layer support nets supported on grids) or a perforated pan or container.
  • An outlet port 414 is fluidly associated with lower portion 410 of sorbent housing 400 and is adapted for discharging an outlet gas or stream passing through sorbent 406 or sorbent housing 400.
  • this discharge stream may be recirculated.
  • the discharge stream may be recirculated to container 102 (e.g., via a first recirculation loop 313 including pumping arrangement 118 and valve 120), or to some point between container 102 and a first stage or structure of adsorption 305, for example, to conduit 307 (e.g., via a second recirculation loop 323 including pumping arrangement 327 and valve 332).
  • heating chamber 420 including a heating element 422, which is adapted for heating sorbent 406 to affect desorption of substances adsorbed thereto, as will be described in further detail hereinbelow.
  • heating chamber 420 is formed of a material having high thermal conductivity, such as aluminum or copper.
  • sorbent 406 includes a large, typically non-disposable sorbent, having a large adsorbing surface area. In some embodiments, sorbent 406 has a specific surface area within a range of 0.1 to 50 m 2 /gram.
  • sorbent 406 includes, largely includes, or consists essentially of a sorbent fabric.
  • sorbent 406 may be made of, or include, rayon fibers and/or fiberglass.
  • rayon fibers and/or fiberglass One exemplary material is a viscose rayon (or simply rayon), which is a fiber that may be made from regenerated wood cellulose.
  • the specific surface area is 0.3m 2 /g, and the viscose rayon is manufactured by Kelheim Fibers (GmbH).
  • sorbent 406 includes sorbent granules (e.g., pellets).
  • sorbent granules e.g., pellets.
  • Various such granules are commercially available, e.g., Tenax® Porous Polymer Adsorbents (Sigma-Aldrich® Co. LLC— Supelco) based on 2,6-diphenyl-p-phenylene oxide, having a nominal particle size of 60-80 mesh, and a specific surface area of 35m 2 /g.
  • sorbent 406 includes a foam such as a metal foam.
  • Figures 5A and 5B illustrate the microstructure of a sorbent fabric and of sorbent granules, respectively.
  • a sorbent fabric 406 has multiple fibers having pores or open spaces therebetween.
  • a sorbent fabric e.g., as shown in Figure 5A
  • a sorbent fabric includes macrofibers or strands 605 having a characteristic diameter d, and pores or open spaces 604 having a characteristic pore diameter D por e-
  • Each of strands may include a plurality of individual fibers.
  • Gas phase molecules such as gas phase molecules of hazardous substances, may be adsorbed onto the surface, e.g., between the individual fibers making up strands 605.
  • the permeability of sorbent 406 may be largely dependent on the characteristic pore diameter D por e- In some embodiments, it is desirable that D por e will be significantly greater than characteristic diameter d (D por e » d).
  • the permeability of sorbent 406, or the characteristic pore diameter (D por e) of pores therein may be of any suitable magnitude.
  • the adsorption surface has a characteristic pore diameter D por e of at least 65 micrometer ( ⁇ ).
  • Figure 6B provides a schematic representation similar to that of Figure 6A, but having microporous sorbent fibers 602.
  • the permeability of sorbent 406 may be largely dependent on the characteristic pore diameter D por e- In some embodiments, it is desirable that D por e will be significantly greater than characteristic diameter d (D por e » d).
  • the permeability characteristics may be substantially identical to those described above, and the characteristic pore diameter D por e, as above, may be at least 65 micrometer ( ⁇ ).
  • the characteristic pore diameter D por e is at least 75 ⁇ , at least 85 ⁇ , at least 100 ⁇ , at least 125 ⁇ , at least 150 ⁇ , at least 200 ⁇ , or at least 300 ⁇ .
  • the characteristic pore diameter D por e is at most 3500 ⁇ , at most 2000 ⁇ , at most 1200 ⁇ , at most 1000 ⁇ , at most 900 ⁇ , at most 750 ⁇ , at most 650 ⁇ , or at most 550 ⁇ .
  • the characteristic pore diameter D por e is within a range of 70 to 1500 ⁇ , 80 to 1500 ⁇ , 100 to 1200 ⁇ , 100 to 1000 ⁇ , 150 to 1200 ⁇ , 200 to 1200 ⁇ , 200 to 1000 ⁇ , 250 to 1200 ⁇ , 300 to 1200 ⁇ , 300 to 1000 ⁇ , 350 to 1000 ⁇ , 350 to 800 ⁇ , or 400 to 1000 ⁇ .
  • sorbent 406 is temperature stable at a lower temperature limit of 0°C and up to an upper temperature limit of at least 70°C.
  • the upper temperature for sorbent stability limit is 85°C, 95°C, 110°C, 130°C, 150°C, 175°C, or 200°C.
  • sorbent 406 when sorbent 406 is a fabric, sorbent 406 may have a compressive strength of at most 3MPa, at most l .OMPa, at most 0.5MPa, at most 0.3MPa, at most 0.2MPa, at most 0. IMPa, at most 0.05MPa, or at most 0.02MPa.
  • sorbent 406 when sorbent 406 is granular or the like, sorbent 406 may have a compressive strength of at most lOMPa, at most 5MPa, at most 2MPa, at most IMPa, at most 0.5MPa, at most 0.2MPa, at most O. lMPa, or at most 0.05MPa.
  • sorbent 406 is configured to have large volumes of gas pass therethrough, preferably without becoming clogged by particulate matter.
  • outlet 414 of sorbent chamber 306 is in fluid flow communication with a conduit 308 having a branch 310 that is in fluid flow communication with an ambient environment via a valve 312.
  • a distal end of conduit 308 is in fluid flow communication with a neutralizing vessel 316 via a valve 318.
  • neutralizing vessel 316 may be partially filled with a suitable liquid 320 or neutralizing agent, as will be known to those of skill in the art.
  • liquid 320 includes at least one neutralizing substance and is adapted to neutralize hazardous or harmful substances present in the gas discharged from conduit 308.
  • the neutralizing substance includes one or more of Fenton's reagent (a solution of peroxide and an iron catalyst), hypochlorite (e.g, sodium or potassium hypochlorite), permanganate (e.g., sodium or potassium permanganate).
  • the level of liquid 320 may advantageously be maintained such that a fluid withdrawal element 326, such as a vacuum pump, may fluidly communicate with a gas- filled portion 324 of neutralizing vessel 316, via a conduit 322.
  • a fluid withdrawal element 326 such as a vacuum pump
  • vacuum pump 326 may fluidly communicate with the ambient environment via an exhaust pipe 328.
  • an inventive method of sampling and processing hazardous substances disposed within a target volume may include sampling the target volume to produce a target volume sample; and contacting the sample with an adsorption surface to produce a loaded sorbent.
  • the loaded sorbent may be exposed so as to deliver vapor to a biosensor such as a sniffing dog, the vapor containing desorbed gas from the loaded sorbent.
  • a biosensor such as a sniffing dog
  • the biosensor may be disposed within one meter of the loaded sorbent, or within one meter of a point where the vapor is discharged to the ambient environment.
  • the vapor may be delivered to an instrumental chemical detection system.
  • the adsorption within sorbent housing 400 in first stage or structure of adsorption 305, which is followed by a controlled desorption step; the desorbed vapor is introduced to a second stage or structure of adsorption 330.
  • Second stage 330 includes at least one adsorption unit 342 containing at least one individual sorbent column or housing 343, each adapted to contain a sorbent 345.
  • Second stage 330 is adapted to fluidly communicate with first stage 305 via a conduit 344, when a valve 347 disposed within conduit 344, between first and second stages 305, 330, is disposed in an at least partially open position.
  • Valve 347 may be optional. The function of valve 347 may be effected in other ways, for example, using a valve 348 disposed within a conduit 346, connected to, and downstream of, second stage 330. Conduit 346 may be disposed, at an end distal to second stage 330, within neutralizing vessel 316.
  • Heating element 340 may be adapted to heat conduit 344 and the surrounding elements of the apparatus, so as to "sterilize” (i.e., eliminate traces of the adsorbed organic molecules, or appreciably reduce the concentration thereof) this section of the apparatus.
  • outlet 302, sorbent chamber 306, and adsorption units 342 are all in fluid flow communication with vacuum pump 326 via valves 304, 318, and 348, such that vacuum pump 326 is adapted to withdraw gas from container 102 via outlet 302, sorbent chamber 306, and/or adsorption units 342, as will be described in further detail hereinbelow.
  • sorbent 345 typically includes, or consists of, a sorbent fabric.
  • the permeability of sorbent 345, and the characteristic pore diameter D pore of pores therein, may be of any suitable magnitude.
  • At least one controller such as fluid transfer controller 350, may be functionally associated with valve 304, valve 312, valve 318, vacuum pump 326, heating element 340, valve 347, and valve 348. Controller 350 is adapted to control fluid transfer through adsorption and fluid transfer arrangement 110 as described in further detail hereinbelow. In some embodiments, fluid transfer controller 350 is also functionally associated with pumping arrangement 118, and is then adapted to control fluid transfer into, within, and out of container 102 via pumping arrangement 118 and adsorption and fluid transfer arrangement 110.
  • apparatus 100 may operate in various operational modes, including a gas withdrawal mode, at least one sampling mode, such as a first sampling mode and a second sampling mode, and a post-processing, or sterilization, mode.
  • Apparatus 100 may operate in a controlled desorption mode, but this may usually effected as part of the second sampling mode.
  • the various modes are further elaborated hereinbelow.
  • Ventilator 106 Prior to the gas withdrawal and first sampling modes, one or more objects to be sampled for the presence of hazardous substances is inserted into container 102, and may be sealed therein from an ambient environment, typically by closing door 104. Ventilator 106 may be activated in a ventilation mode, and in some embodiments, remains activated for the duration of the sampling mode.
  • Gas withdrawal mode and first sampling mode may be largely identical.
  • heating controller 240 maintains valve 220 leading to exhaust pipe 218 in a closed orientation.
  • Heating controller 240 also controls withdrawal of gas from container 102 into recirculation loop 200 via outlet 202, and heating the gas by heating element 212 to a suitable temperature prior to reintroducing the gas into container 102 via inlet 204.
  • recirculation and heating of the gas in container 102 are continuously controlled by heating controller 240 throughout operation of apparatus 100 in the gas withdrawal mode and first sampling mode.
  • Heating controller 240 may initiate operation of recirculation loop 200 and heating element 212 before commencing withdrawal of gas from container 102 via outlet 302.
  • heating controller 240 is configured to control the heating element 212 and recirculation loop 200 such that gas reintroduced into container 102 via inlet 204 has a temperature that exceeds the bulk temperature within container 102 by at most 40°C, at most 35°C, at most 30°C, at most 25 °C, at most 20°C, at most 15°C, or at most 10°C.
  • Controller 350 may be configured to open valve 120, thereby allowing fluid flow from pumping arrangement 118 into container 102. Following a control command from controller 350, pumping arrangement 118 may introduce external gas into container 102 (e.g., via a valved pipe 301), and subsequently controller 350 closes valve 120, resulting in super-atmospheric pressure within container 102.
  • the external gas introduced into container 102 by pumping arrangement 118 includes, or consists essentially of, ambient air.
  • the external gas introduced into container 102 by pumping arrangement 118 includes, mainly includes, or consists essentially of, the discharge stream discharged from first stage of adsorption 305.
  • controller 350 opens valves 304 and 318, closes valve 348, and provides a command for activation of vacuum pump 326.
  • Vacuum pump 326 withdraws gas from container 102, and due to the orientations of the valves and the structure of apparatus 100, the withdrawn gas travels through conduit 307 and port 402 into sorbent chamber 306, where the gas passes through sorbent 406 and organic substances are adsorbed onto the sorbent.
  • the initial withdrawal of gas from container 102 may be performed from an initial state at, or around, ambient or atmospheric pressure.
  • Gas passing through sorbent 406 is withdrawn from sorbent chamber 306 via lower portion 410, outlet port 414 and conduit 314, and may be discharged to the environment.
  • the gas may first be passed through liquid 320 of neutralizing vessel 316.
  • the gas bubbles up from liquid 320 into gas filled portion 324 of vessel 316, and from there, the treated gas may be withdrawn by vacuum pump 326, via conduit 322, and may be discharged from the apparatus via exhaust pipe 328.
  • any hazardous substances not adsorbed by sorbent 406 and still present in the withdrawn gas are neutralized by the neutralizing substance in liquid 320.
  • controller 350 is configured to control pumping arrangement 118 and adsorption and fluid transfer arrangement 110 as described hereinabove to effect an operating cycle so as to periodically obtain cycles of super-atmospheric pressure within container 102 followed by sub-atmospheric pressure within container 102.
  • controller 350 is configured to maintain a maximum pressure within container 102 below 1.5 atmosphere absolute (ata), below 1.4 ata, below 1.3 ata, below 1.25 ata, below 1.2 ata, below 1.15 ata, or below 1.1 ata.
  • a super-atmospheric pressure state of container 102 includes a peak super-atmospheric pressure state, and a sub-atmospheric pressure of container 102 including a peak vacuum state.
  • controller 350 is configured to control pumping arrangement 118 and/or adsorption and fluid transfer arrangement 110 such that pressurization from the peak vacuum state to the peak pressure state, or depressurization from the peak pressure state to the peak vacuum state is achieved over a period of at least 1 second, at least 2 seconds, at least 5 seconds, at least 10 seconds, or at least 20 seconds.
  • controller 350 is further configured to control pumping arrangement 118 and/or adsorption and fluid transfer arrangement 110 such that an absolute value of the transient pressure gradient (dP/dt) within container 102 between the peak pressure state and the peak vacuum state, or between the peak vacuum state and the peak pressure state, is maintained below 1,000 Pa/s, and more typically, within a range of 100 to 1,000 Pa/s, 150 to 1,000 Pa/s, 200 to 1,000 Pa/s, 300 to 1,000 Pa/s, 400 to 1,000 Pa/s, or 200 to 800 Pa/s.
  • dP/dt transient pressure gradient
  • the volume of gas withdrawn by vacuum pump 326 during the operation cycles may be any suitable volume of gas.
  • controller 350 is configured to control pumping arrangement 118 and vacuum pump 326 such that the volume of gas withdrawn by vacuum pump from container 102, and passed through sorbent 406, is at least 0.4, at least 0.6, at least 0.8, at least 1, at least 2, at least 3, at least 5, at least 8, or at least 10m 3 .
  • controller 350 may be further configured to control the fluid transfer arrangement such that a dimensionless volumetric ratio of a sampling volume (Vs) of the withdrawn gas delivered by the fluid transfer arrangement to first sorbent 406, to a total (internal) volume of container 102 (Vc), is at least 0.1, at least 0.2, at least 0.3, at least 0.5, at least 1, at least 2, at least 3, at least 4, or at least 5.
  • Vs sampling volume
  • Vc total (internal) volume of container 102
  • this volumetric ratio (Vs/Vc) is at most 10, at most 8, at most 7, or at most 6.
  • controller 350 is configured to close valves 304 and 318, and to open valves 347, 348, and 312, to enable a second adsorption (or a re-adsorption) phase as described herein.
  • the container can be unsealed, such as by opening door 104, and the target object(s) may be removed from the container.
  • heating element 422 of sorbent chamber 306 may be activated or controlled to heat sorbent 406 so as to effect at least partial desorption of organic molecules adsorbed thereto. In some embodiments, heating is affected for at most 1 minute, at most 30 seconds, at most 20 seconds, at most 15 seconds, or at most 10 seconds, such that appreciable desorption from the surface of sorbent 406 transpires.
  • controller 350 is configured to activate vacuum pump 326, such that the vapor is withdrawn from sorbent housing 400 via port 402 and conduits 307 and 344 into adsorption units 342.
  • the vapor passes through adsorption units 342, such that organic molecules that had been desorbed from sorbent 406 are now adsorbed by sorbents contained in adsorption units 342, resulting in one or more loaded sorbents.
  • the vapor not adsorbed within adsorption units 342 is withdrawn from the columns via conduit 346 and valve 348 into liquid 320 of vessel 316.
  • any hazardous substances not adsorbed by sorbent 406 and still present in the withdrawn vapor are neutralized, oxidized, or otherwise deactivated by the neutralizing, oxidizing, or deactivating substance in liquid 320.
  • the volume of vapor passing through adsorption units 342 may be any suitable volume. However, it will be appreciated that the desorption from sorbent 406 may be carried out at a relatively high temperature and with a relatively small volume of vapor, with respect to the desorption occurring within container 102.
  • controller 350 is configured to control vacuum pump 326 such that a first volume of the withdrawn gas delivered by the fluid transfer arrangement to the first sorbent is larger than a second volume of the gas sample delivered by the fluid transfer arrangement from the first sorbent to the second sorbent.
  • a dimensionless volumetric ratio between the first volume and the second volume may be at least 2, at least 4, at least 8, or at least 12, and more typically, at least 20, at least 50, at least 100, at least 250, at least 500, or at least 1000.
  • the loaded sorbents are analyzed for detection of hazardous substances adsorbed thereto.
  • the heating may compromise the homogeneity of the heating regime, increasing local heating and local pyrolysis, and possibly detracting from the lifetime of the sorbent/adsorption surface.
  • Such rapid heating may be particularly disadvantageous for large, thick sorbent mats, as the homogeneity of the heating distribution within the sorbent depends, inter alia, on the heater temperature distribution, the thermal conductivity of the sorbent material, and other physical and structure parameters of heating system.
  • the equilibrium concentration of target compound adsorbed onto the sorbent/adsorption surface may largely depend on the partial pressure of the target compound. It may be counterproductive, therefore, to utilize large adsorption surface areas (e.g., by using large quantities of sorbent) in an effort to appreciably reduce the partial pressure of the target compound in the adsorption chamber outlet.
  • the inventor has discovered that a balance exists, such that the size of the sorbent should effectively be limited.
  • the quantity of analyte obtained by adsorption may be increased by recirculating the discharge or outlet stream from the first stage of adsorption to an earlier point in the process, e.g., to container 102, or to some point between the container and the first stage of adsorption, substantially as described hereinabove.
  • recirculation may obviate, or largely obviate the need for introducing fresh air upstream of the first adsorption stage, during the sampling process, thereby avoiding an appreciable reduction (dilution) in the target substance concentration in the inlet to the first adsorption stage, which may reduce the total quantity of adsorbed target substance, and in extreme cases, may actually desorb target substance already adsorbed on the adsorption surface of the first adsorption stage.
  • the loaded sorbents are removed from adsorption units 342 and are provided to a biosensor, such as a sniffing dog, for delivery of vapor thereto and for detection of hazardous substances by the biosensor.
  • the biosensor is disposed within a small distance, such as one meter, of the loaded sorbent, while the loaded sorbents are within adsorption units 342. It will be appreciated that in some embodiments, the biosensor may be disposed within a small distance, such as one meter, of sorbent housing 400, and sorbent housing 400 may be unsealed, such as by a window or shutter (not shown), to expose loaded sorbent 406 to the biosensor for delivery of vapor thereto.
  • the loaded sorbents are removed from sorbent adsorption units 342 and are provided to an instrumental chemical detection system (not shown), such as, for example, a mass spectrometer.
  • an instrumental chemical detection system such as, for example, a mass spectrometer.
  • the apparatus may be adapted, and/or operated, so as to enable selective adsorption of gas-phase molecules that tend to desorb at high temperature, due to equilibrium and/or kinetic behavior.
  • various masking agents tend to desorb at lower temperatures than many of the hazardous or explosive substances of interest.
  • the inventors have discovered that by maintaining sorbent 406 below a particular temperature, much of the masking agents adsorbed in sorbent 406 may be desorbed/driven off, leaving a higher ratio of adsorbed hazardous materials to masking agents in sorbent 406.
  • the initial, lower-temperature desorption step may be performed while adsorption units 342 are disconnected from sorbent chamber 306, or while a particular adsorption unit of adsorption units 342 is connected to sorbent chamber 306, while at least a second adsorption unit of adsorption units 342 is disconnected from sorbent chamber 306. Subsequent to the initial, lower-temperature desorption step, the at least second adsorption unit of adsorption units 342 may be connected to sorbent chamber 306.
  • Sorbent 406 may then be heated above the above- described particular temperature, such that a higher ratio (with respect to the initial ratio) of adsorbed hazardous materials to masking agents is desorbed from sorbent 406, and is adsorbed by second adsorption unit of adsorption units 342.
  • sorbent 345 and/or adsorption units 342 may be subjected to preliminary cooling or freezing, prior to passing the desorbed vapors through conduit 344.
  • the lower temperature may favor increased adsorption of these desorbed vapors.
  • the apparatus may be prepared for the next run.
  • a post processing, or sterilization mode may be implemented.
  • container 102 is emptied of any objects contained therein (if such emptying has not yet transpired), and in some embodiments, container 102 remains unsealed so that gas from the ambient environment may enter the container.
  • the container may remain sealed or substantially sealed, until after the temperature in the container has risen to a minimum threshold temperature (e.g., 70°-80°C) for a minimum period (e.g., 30 seconds).
  • a minimum threshold temperature e.g. 70°-80°C
  • pumping arrangement 118 is fluidly disconnected from container 102 by closing valve 120, and/or adsorption and fluid transfer arrangement 110 is disconnected from container 102 by closing valve 304.
  • only recirculation loop 200 is operative during the sterilization mode, at least until the minimum threshold temperature has been achieved in container 102
  • ventilator 106 is activated, and in some embodiments remains activated for the duration of the sterilization mode.
  • container 102 may be ventilated by recirculation pump or blower 210 withdrawing gas from container 102 so that fresh air may be introduced into container 102 through open door 104 or through another inlet.
  • the gas withdrawn by recirculation pump may be removed from the apparatus via exhaust pipe 218 and (open) valve 220.
  • valve 220 and door 104 are closed, disconnecting recirculation loop 200 from the ambient environment.
  • Recirculation pump 210 withdraws gas from container 102, the withdrawn gas is heated by heating element 212, and is reintroduced into container 102 via conduit 216 and inlet 204. This process is repeated until the inside volume of container 102 reaches a desired sterilization temperature and/or until a desired duration has passed.
  • the desired sterilization temperature and the desired sterilization duration may vary depending on the level of contamination of container 102, for example as detected by a biosensor during the sampling mode.
  • the sterilization temperature is at least 80°C, at least 90°C, at least 100°C, at least 150°C, at least 200°C, at least 250°C, or at least 300°C.
  • the sterilization duration is at least 30 seconds, at least 60 seconds, or at least 120 seconds, and typically less than 10 minutes, less than 7 minutes, or less than 5 minutes.
  • the level of sterility of the container is tested, for example by carrying out a sampling cycle without inserting any object into container 102 or by swabbing a surface of the container 102 or of conduits of recirculation loop 200.
  • percent refers to percent by weight, unless specifically indicated otherwise.
  • ratio refers to a weight ratio, unless specifically indicated otherwise.
  • fluidly communicating with means to describe a state between two sections of an apparatus, when any intervening valves are in an at least partially open state.
  • desorption and the like refers to a process that is substantially the opposite from adsorption.
  • neutralizing substance As used herein in the specification and in the claims section that follows, the term “neutralizing substance”, and the like is meant to include an oxidizing substance.
  • pore size or "pore diameter” is determined according to a bubble test for pore size determination, ASTM F316-06 (2011). While the maximum pore size determined by this method may be about 15 microns, in determining the porosity in fibrous or packaging materials, the maximum pore size determined by this method may be about 250 microns (ASTM F2096).

Abstract

An apparatus and method for sampling and processing at least one hazardous substance disposed within a container.

Description

Apparatus for Sampling Chemical Substances, and Methods Therefor
This application draws priority from UK Patent Application Nos. GB1411326.0 and GB1411328.6, both filed June 25, 2014, both of which are incorporated by reference for all purposes as if fully set forth herein.
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to apparatus for sampling chemical substances, and methods therefor.
SUMMARY OF THE INVENTION
According to teachings of the present invention there is provided an apparatus for sampling and processing at least one hazardous substance within a target volume, the apparatus including: a container having the target volume disposed therein; an adsorption arrangement, including a first sorbent having a first adsorption surface and at least a second sorbent having at least a second adsorption surface, the first and second adsorption surfaces being adapted to adsorb gas-phase molecules; a desorption arrangement functionally associated with the first sorbent and adapted to effect desorption of gas-phase molecules adsorbed onto the first adsorption surface; and a fluid transfer arrangement adapted and disposed to: withdraw a first gas sample from within the container during a withdrawal mode; deliver the gas sample to the first adsorption surface, during a first sampling mode; and, subsequently, deliver to the second adsorption surface, during a second sampling mode, a second gas sample containing gas phase molecules desorbed from the first adsorption surface.
According to an aspect of the present invention there is provided an apparatus for sampling and processing at least one target substance within a target volume, the apparatus including: (a) a container having the target volume disposed therein; (b) an adsorption arrangement, including a first adsorption stage and a second adsorption stage, the first adsorption stage having a first adsorption surface, the second adsorption stage including at least a second adsorption stage sorbent having at least a second adsorption surface, the first and second adsorption surfaces being adapted or selected to adsorb gas- phase molecules; (c) a desorption arrangement functionally associated with the first adsorption stage and adapted to effect desorption of gas-phase molecules adsorbed onto the first adsorption surface; and (d) a fluid transfer arrangement adapted and configured to: (i) withdraw a first gas sample from within the container during a withdrawal mode; (ii) deliver the first gas sample to the first adsorption surface, during a first sampling mode; and, subsequently, (iii) deliver to the second adsorption surface, during a second sampling mode, a second gas sample containing gas phase molecules desorbed from the first adsorption surface.
According to yet another aspect of the present invention there is provided a method of the sampling and processing of the at least one hazardous substance disposed within the target volume, the method including: sampling the container to produce the first gas sample; contacting the first gas sample with the first adsorption surface to produce a first loaded sorbent; subsequently desorbing material adsorbed to the first adsorption surface to produce the second gas sample containing the gas phase molecules; and contacting the second gas sample, with the second adsorption surface, to produce at least a second loaded sorbent.
According to yet another aspect of the present invention there is provided an apparatus for sampling and processing at least one hazardous substance within a target volume, the apparatus including: a container having the target volume disposed therein; an adsorption arrangement, including at least one sorbent having an adsorption surface adapted to adsorb gas-phase molecules, and a sorbent housing, the sorbent disposed within the housing; a fluid transfer arrangement, adapted and disposed to: withdraw gas from within the container during a gas withdrawal mode; and deliver the gas to the adsorption surface, during a sampling mode; the adsorption surface having a characteristic pore diameter of at least 65 micrometers (μ).
According to yet another aspect of the present invention there is provided a method of the sampling and processing of the at least one hazardous substance within the container or target volume, the method including: sampling the container or target volume to produce a target volume sample; and contacting the sample with the adsorption surface to produce a loaded sorbent.
According to further features in the described preferred embodiments, the container has minimum dimensions of 0.5 meters by 0.5 meters by 0.5 meters.
According to still further features in the described preferred embodiments, at least one of the first and second adsorption surfaces have a characteristic pore diameter of at least 65μ, at least 75μ, at least 85μ, at least 100μ, at least 125μ, at least 150μ, at least 200μ, or at least 300μ.
According to still further features in the described preferred embodiments, the characteristic pore diameter is at most 3500μ, at most 2000μ, at most 1200μ, at most ΙΟΟΟμ, at most 900μ, at most 750μ, at most 650μ, or at most 550μ.
According to still further features in the described preferred embodiments, the characteristic pore diameter is within a range of 70 to 1500μ, 80 to 1500μ, 100 to 1200μ, 100 to 1000μ, 150 to 1200μ, 200 to 1200μ, 200 to 1000μ, 250 to 1200μ, 300 to 1200μ, 300 to 1000μ, 350 to 1000μ, 350 to 800μ, or 400 to 1000μ.
According to still further features in the described preferred embodiments, at least one of the first and second sorbents is temperature stable at a lower temperature limit of 0°C and up to an upper temperature limit of at least 70°C.
According to still further features in the described preferred embodiments, the upper temperature limit is 85°C, 95°C, 110°C, 130°C, 150°C, 175°C, or 200°C.
According to still further features in the described preferred embodiments, the apparatus further includes a heating arrangement, adapted to heat the target volume.
According to still further features in the described preferred embodiments, the heating arrangement includes a recirculation loop attached to the container to form an outlet for withdrawing the gas from the container, and an inlet for returning the gas to the container; a recirculation pump, fluidly associated with the loop, and adapted to effect forced circulation of the gas by withdrawing the gas via the outlet and returning the gas to the container via the inlet; and a heating arrangement, associated with the loop, and adapted to heat the gas as the gas transits the recirculation loop.
According to still further features in the described preferred embodiments, the recirculation pump and heating arrangement are controlled such that the gas reintroduced to the container via the inlet has a temperature that exceeds a bulk temperature within the container by at most 40°C, at most 35°C, at most 30°C, at most 25 °C, at most 20°C, at most 15°C, or at most 10°C.
According to still further features in the described preferred embodiments, the container is sealed, during the gas withdrawal mode, from an ambient environment.
According to still further features in the described preferred embodiments, the apparatus further includes a pumping arrangement, fluidly associated with the container, and adapted to introduce an external gas to the container.
According to still further features in the described preferred embodiments, the pumping arrangement is adapted and positioned such that the external gas includes, or consists essentially of, ambient air.
According to still further features in the described preferred embodiments, at least one of the first and second sorbents has a specific surface area within a range of 0.1 to 50 m2/gram.
According to still further features in the described preferred embodiments, any filtration arrangement for filtering the gas from within the container is disposed downstream of the adsorption arrangement, so as to receive a portion of the gas after the portion has been discharged from the adsorption arrangement.
According to still further features in the described preferred embodiments, at least one of a first gas flow path between the container and the first sorbent, and a second gas flow path between the first and second sorbents, or both flow paths, are free of any gas filtration arrangement.
According to still further features in the described preferred embodiments, the apparatus further includes a ventilating arrangement having a ventilator disposed within the container, and adapted, in a ventilation mode, to mix the gas within the container.
According to still further features in the described preferred embodiments, the container is semi-rigid, at least semi-rigid, or rigid.
According to still further features in the described preferred embodiments, the apparatus further includes a controller, configured to control the fluid transfer arrangement.
According to still further features in the described preferred embodiments, the controller is configured to control the fluid transfer arrangement to periodically attain a sub-atmospheric pressure within the container, during a single sampling run.
According to still further features in the described preferred embodiments, the controller is configured to control the fluid transfer arrangement to periodically attain a super-atmospheric pressure within the container, during a single sampling run.
According to still further features in the described preferred embodiments, the controller is configured to control the fluid transfer arrangement to periodically attain, within the container, a sub-atmospheric pressure, and a super-atmospheric pressure, during a single sampling run.
According to still further features in the described preferred embodiments, the controller is further configured to maintain a maximum pressure within the container below 1.5 atmosphere absolute (ata), below 1.4 ata, below 1.3 ata, below 1.25 ata, below 1.2 ata, below 1.15 ata, or below 1.1 ata.
According to still further features in the described preferred embodiments, the controller is further configured to control the fluid transfer arrangement to effect at least one operating cycle within a sampling run, wherein, in each cycle of the at least one operating cycle, the container undergoes pressurization from a sub-atmospheric pressure state to a super-atmospheric pressure state.
According to still further features in the described preferred embodiments, the super-atmospheric pressure state includes a peak pressure state, and the sub-atmospheric pressure includes a peak vacuum state, the controller further configured to control the fluid transfer arrangement such that the pressurization from the peak vacuum state to the peak pressure state, or vice versa, within a single cycle of the operating cycle, is achieved over a period of at least 1 second, at least 2 seconds, at least 5 seconds, at least 10 seconds, or at least 20 seconds.
According to still further features in the described preferred embodiments, the super-atmospheric pressure state includes a peak pressure state, and the sub-atmospheric pressure includes a peak vacuum state, the controller further configured to control the fluid transfer arrangement such that a transient pressure gradient (dP/dt) within the container is maintained below 1,000 Pa/s, or within a range of 100 to 1,000 Pa/s, 150 to 1,000 Pa/s, 200 to 1,000 Pa/s, 300 to 1,000 Pa/s, 400 to 1,000 Pa/s, or 200 to 800 Pa/s, within at least one cycle of the operating cycle.
According to still further features in the described preferred embodiments, the controller is further configured to control the fluid transfer arrangement such that a first volume of the first gas sample delivered by the fluid transfer arrangement to the first sorbent is larger than a second volume of the second gas sample delivered by the fluid transfer arrangement from the first sorbent to the second sorbent, a dimensionless volumetric ratio between the first volume and the second volume being at least 2, at least 4, at least 8, at least 20, at least 50, at least 100, at least 250, at least 500, or at least 1000.
According to still further features in the described preferred embodiments, the container has a total volume Vc, the controller being further configured to control the fluid transfer arrangement such that a dimensionless volumetric ratio of a sampling volume (Vs) of the first gas sample to the first sorbent, to the total volume (Vc), is at least 0.1, at least 0.2, at least 0.3, at least 0.5, at least 1, at least 2, at least 3, at least 4, or at least 5.
According to still further features in the described preferred embodiments, the volumetric ratio (Vs/Vc) is at most 10, at most 8, at most 7, or at most 6.
According to still further features in the described preferred embodiments, the controller is further configured to initiate a sterilization mode within the apparatus, following the sampling mode.
According to still further features in the described preferred embodiments, the sterilization mode including heating an internal volume of the container, using at least one heating arrangement, to at least 70°C, at least 85°C, at least 100°C at least 150°C, at least 200°C, at least 250°C, or at least 300°C.
According to still further features in the described preferred embodiments, at least one of the first and second sorbents includes, largely (more than 50% of the surface area) includes, or consists essentially of a sorbent fabric.
According to still further features in the described preferred embodiments, the sorbent fabric includes, largely includes, or consists essentially of a material selected from the group consisting of rayon fiber and fiberglass.
According to still further features in the described preferred embodiments, the first sorbent includes, largely includes, or consists essentially of sorbent granules.
According to still further features in the described preferred embodiments, the adsorption arrangement includes a first sorbent housing having the first sorbent disposed therein and including a sealed chamber having at least a first port and a second port, the ports fluidly intercommunicating via the chamber, and via the first sorbent.
According to still further features in the described preferred embodiments, at least one of the first and second sorbents includes the sorbent fabric, a compressive strength of the sorbent fabric being at most 3MPa, at most l .OMPa, at most 0.5MPa, at most 0.3MPa, at most 0.2MPa, at most 0. IMPa, at most 0.05MPa, or at most 0.02MPa.
According to still further features in the described preferred embodiments, at least one of the first and second sorbents includes the sorbent granules, a compressive strength of the sorbent granules being at most lOMPa, at most 5MPa, at most 2MPa, at most IMPa, at most 0.5MPa, at most 0.2MPa, at most 0. IMPa, or at most 0.05MPa.
According to still further features in the described preferred embodiments, the apparatus further includes a detection arrangement adapted to receive the second sorbent.
According to still further features in the described preferred embodiments, the method further includes exposing at least one of the first and second loaded sorbents to deliver vapor to a biosensor.
According to still further features in the described preferred embodiments, the biosensor is a sniffing dog.
According to still further features in the described preferred embodiments, the method further includes disposing the biosensor within one meter of at least one of the first loaded sorbent and the second loaded sorbent.
According to still further features in the described preferred embodiments, the method further includes delivering the second loaded sorbent to deliver vapor to an instrumental chemical detection system.
According to still further features in the described preferred embodiments, the maximum pressure differential across the first adsorption surface, during the contacting of the sample therewith, is less than 1,000 Pa, less than 800 Pa, less than 600 Pa, less than 500 Pa, less than 400 Pa, less than 300 Pa, less than 200 Pa, less than 150 Pa, or less than 100 Pa.
According to still further features in the described preferred embodiments, the sampling of the container to produce the first gas sample is effected within 3 minutes, within 2.5 minutes, within 2 minutes, within 1.5 minutes, or within 1 minute, while maintaining a maximum pressure differential across the first adsorption surface, during the contacting of the sample therewith, below 1,000 Pa, below 800 Pa, below 600 Pa, below 500 Pa, below 400 Pa, below 300 Pa, below 200 Pa, below 150 Pa, or below 100 Pa.
According to still further features in the described preferred embodiments, the first gas sample has a volume of at least 0.1m3, at least 0.2m3, at least 0.3m3, at least
3 3 3 3 3 3
0.5m , at least 0.7m , at least lm , at least 1.5m , at least 2m , at least 3m , or at least 5m3.
According to still further features in the described preferred embodiments, the method further includes, subsequent to step (e), heating the container to at least at least 70°C, at least 85 °C, at least 100°C at least 150°C, at least 200°C, at least 250°C, or at least 300°C, so as to desorb or otherwise remove any of the at least one hazardous substance disposed within the container. According to still further features in the described preferred embodiments, the hazardous substance includes at least one of trinitrotoluene (TNT) and an explosive nitramine compound.
According to still further features in the described preferred embodiments, the desorbing of material adsorbed to the first adsorption surface is performed in at least first and second time periods, the second time period being subsequent to the first time period, wherein, in the first time period, the desorbing is effected at a first temperature, and in the second time period, the desorbing is effected at a second temperature, and wherein the second temperature exceeds the first temperature.
According to still further features in the described preferred embodiments, at least a fraction of the gas desorbed during the first time period is diverted from contacting the second adsorption surface.
According to still further features in the described preferred embodiments, the second sorbent includes a first sorbent unit and a second sorbent unit, and at least a fraction of gas desorbed during the first time period is contacted with the second adsorption surface of the first sorbent unit, and at least a fraction of gas desorbed during the second time period is contacted with the second adsorption surface of the second sorbent unit.
According to still further features in the described preferred embodiments, the second sorbent includes a first sorbent unit and a second sorbent unit, and at least a fraction of gas desorbed during the first time period is contacted with the second adsorption surface of the first sorbent unit, and at least a fraction of gas desorbed during the second time period is contacted with the second adsorption surface of the second sorbent unit, so as to improve chemical selectivity or reduce a concentration of masking agents in the second sorbent unit.
According to still further features in the described preferred embodiments, the sorbent material includes, or consists of, a fabric sorbent.
According to still further features in the described preferred embodiments, the sorbent material includes rayon fiber or fiberglass.
According to still further features in the described preferred embodiments, the compressive strength of the sorbent fabric is at most 3MPa, at most l .OMPa, at most 0.5MPa, at most 0.3MPa, at most 0.2MPa, at most O. lMPa, at most 0.05MPa, or at most 0.02MPa. According to still further features in the described preferred embodiments, the sorbent includes, or consists of, sorbent granules.
According to still further features in the described preferred embodiments, the compressive strength of the sorbent granules is at most lOMPa, at most 5MPa, at most 2MPa, at most IMPa, at most 0.5MPa, at most 0.2MPa, at most O. lMPa, or at most 0.05MPa.
According to still further features in the described preferred embodiments, there is provided a method of sampling and processing at least one hazardous substance within a target volume, the method including any feature described, either individually or in combination with any feature, in any configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Throughout the drawings, like-referenced characters are used to designate like elements.
In the drawings:
Figure 1 is a schematic illustration of an embodiment of an apparatus for sampling and processing hazardous substances within a target volume, constructed and operative in accordance with an embodiment of the teachings herein;
Figure 2 is a schematic illustration of a heating arrangement forming part of the apparatus of Figure 1, constructed and operative in accordance with an embodiment of the teachings herein;
Figure 3 is a schematic illustration of an embodiment of an adsorption arrangement and a fluid transfer arrangement forming part of the apparatus of Figure 1, constructed and operative in accordance with an embodiment of the teachings herein; Figure 4 is a schematic illustration of a sorbent chamber forming part of the adsorption arrangement of Figure 3 constructed and operative in accordance with the teachings herein;
Figures 5A and 5B are images representing the microstructure of two different sorbent materials which may be used in the adsorption arrangement of Figure 3 and the sorbent chamber of Figure 4, wherein Figure 5 A represents a sorbent fabric and Figure 5B represents sorbent granules; and
Figures 6A and 6B are schematic representations of exemplary adsorption surfaces used in the adsorption arrangement of Figure 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The principles and operation of the present invention may be better understood with reference to the drawings and the accompanying description.
Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
Reference is now made to Figure 1, which is a schematic illustration of an embodiment of an apparatus for sampling and processing hazardous substances within a target volume, constructed and operative in accordance with an embodiment of the teachings herein.
As seen in Figure 1, an apparatus 100 for sampling and processing at least one target substance, typically a hazardous substance, such as explosive substances (e.g., TNT, RDX, HDX) or pesticides, includes a container 102 having a target volume 109 disposed therein. Target volume 109 may contain a stack or pallet of cartons or suitcases, by way of example. Container 102 may have any suitable dimensions. In some embodiments, however, container 102 has a minimum volume of 0.2 cubic meters and minimum dimensions of 0.5 meters by 0.5 meters by 0.5 meters. In some embodiments, the target volume of the container is configured to receive at least one object (not shown) to be sampled for the presence of at least one hazardous substance. The objects to be examined may be introduced and removed from container 102 via a door 104. Container 102 and door 104 may be adapted to be sealable from an ambient environment.
In some embodiments, a ventilator 106 is disposed within container 102 and may be adapted to mix gas present within container 102 prior to and/or during withdrawal of the gas from the container. In some embodiments, a pressure sensor or meter 108 is functionally associated with container 102 and is configured to measure the pressure therein. In some embodiments, pressure meter 108 is mounted on container 102 at a location visible to a human operator of apparatus 100.
Functionally associated with container 102 is an adsorption and fluid transfer arrangement 110, whose components and functionality are described in further detail hereinbelow with reference to Figures 3 - 6B.
In some embodiments, a heating arrangement 116 is functionally associated with container 102, and may be adapted to heat the gas within container 102, and more specifically, the gas within target volume 109, prior to and/or during withdrawal of the gas from container 102, and/or during sterilization thereof. The components and functionality of heating arrangement 116 are described in further detail hereinbelow with reference to Figure 2.
A pumping arrangement 118, such as an overpressure blower, is fluidly associated with container 102 via a valve 120, and is adapted to introduce an external gas, such as ambient air, into container 102, while valve 120 is open, e.g., during a withdrawal mode (or a portion thereof), and typically but not exclusively, in a sampling mode.
In some embodiments, a controller (similar or substantially identical to controller 350 shown in Figure 3) is functionally associated with pumping arrangement 118, and may be configured to control fluid flow into and out of container 102, as is described in further detail hereinbelow.
Reference is now made to Figure 2, which is a schematic illustration of heating arrangement 116 forming part of the apparatus of Figure 1, constructed and operative in accordance with an embodiment of the teachings herein.
Heating arrangement 116 may include a recirculation loop 200, attached to container 102 at an outlet 202 for withdrawing gas from container 102 and at an inlet 204 for returning the gas, following heating thereof, to container 102. Flow of gas through outlet 202 may be controlled by an outlet valve 206 and flow of gas through inlet 204 may be controlled by an inlet valve 208, as described in further detail hereinbelow.
During recirculation or recirculation mode, a recirculation pump or blower 210 is in fluid communication with recirculation loop 200, and is adapted to effect forced circulation of gas from container 102 by withdrawing the gas from container 102 via outlet 202 and returning the heated gas to container 102 via inlet 204.
A heating element 212 may be in fluid communication with recirculation loop 200, and may be adapted to heat the gas withdrawn from container 102 as the gas transits recirculation loop 200. In some embodiments, a thermostat (not shown) is functionally associated with heating element 212, such that the heating temperature of the gas passing through the heating element 212 can be controlled by a controller 240 (or controller 350 shown in Figure 3) or by an operator of the apparatus 100.
A conduit 214 disposed downstream of heating element 212 may include, or be connected to, a recirculation branch 216 adapted to reintroduce heated gas to container 102, via inlet 204. Conduit 214 may be further connected to an exhaust pipe branch 218 associated with a valve 220 and adapted for selectively removing gas from recirculation loop 200, as will be described hereinbelow. In some embodiments, recirculation branch 216 has functionally associated therewith a thermocouple port 222, adapted for enabling control of the temperature of gas reintroduced into container 102 via inlet 204.
Arrows 224, 226, 228, and 230 indicate the gas flow direction through recirculation loop 200, where arrow 228 indicates reintroduction of gas to container 102 via recirculation branch 216, and arrow 230 indicates removal of gas from recirculation loop 200 via exhaust pipe branch 218.
In some embodiments, a recirculation and heating controller 240 is functionally associated with recirculation pump 210 and/or with heating element 212, and is adapted to control the volume of gas drawn from container 102, the volume of gas reintroduced into container 102, the temperature to which heating element 212 heats the gas passing therethrough, and/or the orientations (e.g., degree of opening) of valves 206, 208, and 220.
Reference is now made to Figure 3, which is a schematic illustration of an embodiment of an adsorption arrangement and a fluid transfer arrangement forming part of the apparatus of Figure 1, constructed and operative in accordance with an embodiment of the teachings herein.
As seen in Figure 3, adsorption and fluid transfer arrangement 110 of Figure 1 includes an outlet 302 fluidly associated with container 102 for withdrawal of gas therefrom. An outlet valve 304 is functionally associated with outlet 302, and is configured to close the outlet 302 upon demand, as described in further detail hereinbelow.
A sorbent or adsorption chamber 306 is in fluid communication with outlet 302 via valve 304 and a conduit 307. As seen in Figure 4, which is a schematic illustration of sorbent chamber 306, sorbent chamber 306 has a sorbent housing 400 including an inlet port 402 which may be in fluid flow communication with outlet 302 of container 102, and through which gas from container 102 can enter sorbent housing 400.
In some embodiments, sorbent housing 400 is sealed from the environment. Inside sorbent housing 400 may be disposed a sorbent 406, which may have an adsorption surface adapted to adsorb gas-phase molecules of hazardous substances. Sorbent 406 allows fluid communication between an upper portion 408 of housing 400 above the sorbent 406 and a lower portion 410 of the housing 400 below the sorbent 406
In some embodiments, sorbent 406 is supported in sorbent housing 400 by a permeable support element or arrangement 412, such as a support net (including multilayer support nets, and multi-layer support nets supported on grids) or a perforated pan or container. It will be readily appreciated that such arrangements have adsorption surface area for adsorption of hazardous (target) substances. Such adsorption surface area may be utilized in addition to the adsorption surface area of any sorbent 406. In some cases, in which the support arrangement has sufficient adsorption surface area, the need for a sorbent may be obviated. An outlet port 414 is fluidly associated with lower portion 410 of sorbent housing 400 and is adapted for discharging an outlet gas or stream passing through sorbent 406 or sorbent housing 400. In some embodiments, this discharge stream may be recirculated. For example, with reference again to Figure 3, the discharge stream may be recirculated to container 102 (e.g., via a first recirculation loop 313 including pumping arrangement 118 and valve 120), or to some point between container 102 and a first stage or structure of adsorption 305, for example, to conduit 307 (e.g., via a second recirculation loop 323 including pumping arrangement 327 and valve 332). Functionally associated with sorbent housing 400 is a heating chamber 420 including a heating element 422, which is adapted for heating sorbent 406 to affect desorption of substances adsorbed thereto, as will be described in further detail hereinbelow. In some embodiments, heating chamber 420 is formed of a material having high thermal conductivity, such as aluminum or copper.
In some embodiments, sorbent 406 includes a large, typically non-disposable sorbent, having a large adsorbing surface area. In some embodiments, sorbent 406 has a specific surface area within a range of 0.1 to 50 m2/gram.
While any suitable type of sorbent may be used for implementation of the teachings herein, in some embodiments, sorbent 406 includes, largely includes, or consists essentially of a sorbent fabric. In some such embodiments, sorbent 406 may be made of, or include, rayon fibers and/or fiberglass. One exemplary material is a viscose rayon (or simply rayon), which is a fiber that may be made from regenerated wood cellulose. In an exemplary embodiment, the specific surface area is 0.3m2/g, and the viscose rayon is manufactured by Kelheim Fibers (GmbH).
In some embodiments, sorbent 406 includes sorbent granules (e.g., pellets). Various such granules are commercially available, e.g., Tenax® Porous Polymer Adsorbents (Sigma-Aldrich® Co. LLC— Supelco) based on 2,6-diphenyl-p-phenylene oxide, having a nominal particle size of 60-80 mesh, and a specific surface area of 35m2/g.
In some embodiments, sorbent 406 includes a foam such as a metal foam.
Figures 5A and 5B illustrate the microstructure of a sorbent fabric and of sorbent granules, respectively. As seen in Figure 5A, a sorbent fabric 406 has multiple fibers having pores or open spaces therebetween. As shown in Figure 6A, a sorbent fabric (e.g., as shown in Figure 5A) includes macrofibers or strands 605 having a characteristic diameter d, and pores or open spaces 604 having a characteristic pore diameter Dpore- Each of strands may include a plurality of individual fibers. Gas phase molecules, such as gas phase molecules of hazardous substances, may be adsorbed onto the surface, e.g., between the individual fibers making up strands 605. The permeability of sorbent 406 may be largely dependent on the characteristic pore diameter Dpore- In some embodiments, it is desirable that Dpore will be significantly greater than characteristic diameter d (Dpore » d).
The permeability of sorbent 406, or the characteristic pore diameter (Dpore) of pores therein, may be of any suitable magnitude. In some embodiments, such as embodiments in which it is desired that particles, such as dust particles, pass through the sorbent without appreciable clogging of sorbent 406 or preventing adsorption of gas- phase molecules on the adsorption surface of the sorbent, the adsorption surface has a characteristic pore diameter Dpore of at least 65 micrometer (μ).
Figure 6B provides a schematic representation similar to that of Figure 6A, but having microporous sorbent fibers 602. Microporous sorbent fibers 602, e.g., made of, or including, activated carbon, have a characteristic diameter d, and pores or open spaces 604 having a characteristic pore diameter Dpore- Gas phase molecules, such as gas phase molecules of hazardous substances, may be adsorbed onto the surface of microporous fibers 602. The permeability of sorbent 406 may be largely dependent on the characteristic pore diameter Dpore- In some embodiments, it is desirable that Dpore will be significantly greater than characteristic diameter d (Dpore » d). The permeability characteristics may be substantially identical to those described above, and the characteristic pore diameter Dpore, as above, may be at least 65 micrometer (μ).
In some embodiments, the characteristic pore diameter Dpore is at least 75 μ, at least 85μ, at least 100μ, at least 125μ, at least 150μ, at least 200μ, or at least 300μ.
In some embodiments, the characteristic pore diameter Dpore is at most 3500μ, at most 2000μ, at most 1200μ, at most 1000μ, at most 900μ, at most 750μ, at most 650μ, or at most 550μ.
In some embodiments, the characteristic pore diameter Dpore is within a range of 70 to 1500μ, 80 to 1500μ, 100 to 1200μ, 100 to 1000μ, 150 to 1200μ, 200 to 1200μ, 200 to 1000μ, 250 to 1200μ, 300 to 1200μ, 300 to 1000μ, 350 to 1000μ, 350 to 800μ, or 400 to 1000μ.
In some embodiments, sorbent 406 is temperature stable at a lower temperature limit of 0°C and up to an upper temperature limit of at least 70°C. In some embodiments, the upper temperature for sorbent stability limit is 85°C, 95°C, 110°C, 130°C, 150°C, 175°C, or 200°C.
In some embodiments, for example, when sorbent 406 is a fabric, sorbent 406 may have a compressive strength of at most 3MPa, at most l .OMPa, at most 0.5MPa, at most 0.3MPa, at most 0.2MPa, at most 0. IMPa, at most 0.05MPa, or at most 0.02MPa.
In some embodiments, for example, when sorbent 406 is granular or the like, sorbent 406 may have a compressive strength of at most lOMPa, at most 5MPa, at most 2MPa, at most IMPa, at most 0.5MPa, at most 0.2MPa, at most O. lMPa, or at most 0.05MPa.
In some embodiments, sorbent 406 is configured to have large volumes of gas pass therethrough, preferably without becoming clogged by particulate matter.
Returning to Figure 3, it is seen that outlet 414 of sorbent chamber 306 is in fluid flow communication with a conduit 308 having a branch 310 that is in fluid flow communication with an ambient environment via a valve 312. A distal end of conduit 308 is in fluid flow communication with a neutralizing vessel 316 via a valve 318.
During operation, neutralizing vessel 316 may be partially filled with a suitable liquid 320 or neutralizing agent, as will be known to those of skill in the art. In some embodiments, liquid 320 includes at least one neutralizing substance and is adapted to neutralize hazardous or harmful substances present in the gas discharged from conduit 308. In some embodiments, the neutralizing substance includes one or more of Fenton's reagent (a solution of peroxide and an iron catalyst), hypochlorite (e.g, sodium or potassium hypochlorite), permanganate (e.g., sodium or potassium permanganate).
The level of liquid 320 may advantageously be maintained such that a fluid withdrawal element 326, such as a vacuum pump, may fluidly communicate with a gas- filled portion 324 of neutralizing vessel 316, via a conduit 322. Typically, vacuum pump 326 may fluidly communicate with the ambient environment via an exhaust pipe 328.
Using any of the apparatus embodiments described herein, an inventive method of sampling and processing hazardous substances disposed within a target volume may include sampling the target volume to produce a target volume sample; and contacting the sample with an adsorption surface to produce a loaded sorbent.
In some embodiments, the loaded sorbent may be exposed so as to deliver vapor to a biosensor such as a sniffing dog, the vapor containing desorbed gas from the loaded sorbent. To this end, the biosensor may be disposed within one meter of the loaded sorbent, or within one meter of a point where the vapor is discharged to the ambient environment.
Alternatively or additionally, the vapor may be delivered to an instrumental chemical detection system.
In another aspect of the present invention, the adsorption within sorbent housing 400 (effected by sorbent 406) in first stage or structure of adsorption 305, which is followed by a controlled desorption step; the desorbed vapor is introduced to a second stage or structure of adsorption 330. Second stage 330 includes at least one adsorption unit 342 containing at least one individual sorbent column or housing 343, each adapted to contain a sorbent 345. Second stage 330 is adapted to fluidly communicate with first stage 305 via a conduit 344, when a valve 347 disposed within conduit 344, between first and second stages 305, 330, is disposed in an at least partially open position.
Valve 347 may be optional. The function of valve 347 may be effected in other ways, for example, using a valve 348 disposed within a conduit 346, connected to, and downstream of, second stage 330. Conduit 346 may be disposed, at an end distal to second stage 330, within neutralizing vessel 316.
Between first and second stages 305, 330, e.g., within or around conduit 344, may be disposed a heating element 340. Heating element 340 may be adapted to heat conduit 344 and the surrounding elements of the apparatus, so as to "sterilize" (i.e., eliminate traces of the adsorbed organic molecules, or appreciably reduce the concentration thereof) this section of the apparatus.
It will be appreciated that outlet 302, sorbent chamber 306, and adsorption units 342 are all in fluid flow communication with vacuum pump 326 via valves 304, 318, and 348, such that vacuum pump 326 is adapted to withdraw gas from container 102 via outlet 302, sorbent chamber 306, and/or adsorption units 342, as will be described in further detail hereinbelow.
While any suitable type of sorbent may be used in adsorption units 342, sorbent 345 typically includes, or consists of, a sorbent fabric.
The permeability of sorbent 345, and the characteristic pore diameter Dpore of pores therein, may be of any suitable magnitude.
At least one controller, such as fluid transfer controller 350, may be functionally associated with valve 304, valve 312, valve 318, vacuum pump 326, heating element 340, valve 347, and valve 348. Controller 350 is adapted to control fluid transfer through adsorption and fluid transfer arrangement 110 as described in further detail hereinbelow. In some embodiments, fluid transfer controller 350 is also functionally associated with pumping arrangement 118, and is then adapted to control fluid transfer into, within, and out of container 102 via pumping arrangement 118 and adsorption and fluid transfer arrangement 110.
In use, apparatus 100 may operate in various operational modes, including a gas withdrawal mode, at least one sampling mode, such as a first sampling mode and a second sampling mode, and a post-processing, or sterilization, mode. Apparatus 100 may operate in a controlled desorption mode, but this may usually effected as part of the second sampling mode. The various modes are further elaborated hereinbelow.
Prior to the gas withdrawal and first sampling modes, one or more objects to be sampled for the presence of hazardous substances is inserted into container 102, and may be sealed therein from an ambient environment, typically by closing door 104. Ventilator 106 may be activated in a ventilation mode, and in some embodiments, remains activated for the duration of the sampling mode.
Gas withdrawal mode and first sampling mode may be largely identical. During gas withdrawal mode, and typically during first sampling mode, heating controller 240 maintains valve 220 leading to exhaust pipe 218 in a closed orientation. Heating controller 240 also controls withdrawal of gas from container 102 into recirculation loop 200 via outlet 202, and heating the gas by heating element 212 to a suitable temperature prior to reintroducing the gas into container 102 via inlet 204. In some embodiments, recirculation and heating of the gas in container 102 are continuously controlled by heating controller 240 throughout operation of apparatus 100 in the gas withdrawal mode and first sampling mode.
Heating controller 240 may initiate operation of recirculation loop 200 and heating element 212 before commencing withdrawal of gas from container 102 via outlet 302.
In some embodiments, heating controller 240 is configured to control the heating element 212 and recirculation loop 200 such that gas reintroduced into container 102 via inlet 204 has a temperature that exceeds the bulk temperature within container 102 by at most 40°C, at most 35°C, at most 30°C, at most 25 °C, at most 20°C, at most 15°C, or at most 10°C.
Controller 350 may be configured to open valve 120, thereby allowing fluid flow from pumping arrangement 118 into container 102. Following a control command from controller 350, pumping arrangement 118 may introduce external gas into container 102 (e.g., via a valved pipe 301), and subsequently controller 350 closes valve 120, resulting in super-atmospheric pressure within container 102. In some embodiments, the external gas introduced into container 102 by pumping arrangement 118 includes, or consists essentially of, ambient air. In some embodiments, the external gas introduced into container 102 by pumping arrangement 118 includes, mainly includes, or consists essentially of, the discharge stream discharged from first stage of adsorption 305.
Following production of super-atmospheric pressure in container 102, controller 350 opens valves 304 and 318, closes valve 348, and provides a command for activation of vacuum pump 326. Vacuum pump 326 withdraws gas from container 102, and due to the orientations of the valves and the structure of apparatus 100, the withdrawn gas travels through conduit 307 and port 402 into sorbent chamber 306, where the gas passes through sorbent 406 and organic substances are adsorbed onto the sorbent.
Alternatively, the initial withdrawal of gas from container 102 may be performed from an initial state at, or around, ambient or atmospheric pressure.
Gas passing through sorbent 406 is withdrawn from sorbent chamber 306 via lower portion 410, outlet port 414 and conduit 314, and may be discharged to the environment. In some embodiments, the gas may first be passed through liquid 320 of neutralizing vessel 316. The gas bubbles up from liquid 320 into gas filled portion 324 of vessel 316, and from there, the treated gas may be withdrawn by vacuum pump 326, via conduit 322, and may be discharged from the apparatus via exhaust pipe 328.
In some embodiments, as the withdrawn gas bubbles through liquid 320 and into gas filled portion 324 of vessel 316, any hazardous substances not adsorbed by sorbent 406 and still present in the withdrawn gas are neutralized by the neutralizing substance in liquid 320.
Following withdrawal of gas from container 102 by vacuum pump 326, a sub- atmospheric pressure exists within container 102.
In some embodiments, during a single sampling run of apparatus 100, controller 350 is configured to control pumping arrangement 118 and adsorption and fluid transfer arrangement 110 as described hereinabove to effect an operating cycle so as to periodically obtain cycles of super-atmospheric pressure within container 102 followed by sub-atmospheric pressure within container 102.
In some embodiments, controller 350 is configured to maintain a maximum pressure within container 102 below 1.5 atmosphere absolute (ata), below 1.4 ata, below 1.3 ata, below 1.25 ata, below 1.2 ata, below 1.15 ata, or below 1.1 ata.
In some embodiments, a super-atmospheric pressure state of container 102 includes a peak super-atmospheric pressure state, and a sub-atmospheric pressure of container 102 including a peak vacuum state. In such embodiments, controller 350 is configured to control pumping arrangement 118 and/or adsorption and fluid transfer arrangement 110 such that pressurization from the peak vacuum state to the peak pressure state, or depressurization from the peak pressure state to the peak vacuum state is achieved over a period of at least 1 second, at least 2 seconds, at least 5 seconds, at least 10 seconds, or at least 20 seconds.
In some embodiments, controller 350 is further configured to control pumping arrangement 118 and/or adsorption and fluid transfer arrangement 110 such that an absolute value of the transient pressure gradient (dP/dt) within container 102 between the peak pressure state and the peak vacuum state, or between the peak vacuum state and the peak pressure state, is maintained below 1,000 Pa/s, and more typically, within a range of 100 to 1,000 Pa/s, 150 to 1,000 Pa/s, 200 to 1,000 Pa/s, 300 to 1,000 Pa/s, 400 to 1,000 Pa/s, or 200 to 800 Pa/s.
The volume of gas withdrawn by vacuum pump 326 during the operation cycles may be any suitable volume of gas. In some embodiments, controller 350 is configured to control pumping arrangement 118 and vacuum pump 326 such that the volume of gas withdrawn by vacuum pump from container 102, and passed through sorbent 406, is at least 0.4, at least 0.6, at least 0.8, at least 1, at least 2, at least 3, at least 5, at least 8, or at least 10m3.
In some embodiments, controller 350 may be further configured to control the fluid transfer arrangement such that a dimensionless volumetric ratio of a sampling volume (Vs) of the withdrawn gas delivered by the fluid transfer arrangement to first sorbent 406, to a total (internal) volume of container 102 (Vc), is at least 0.1, at least 0.2, at least 0.3, at least 0.5, at least 1, at least 2, at least 3, at least 4, or at least 5.
In some embodiments, this volumetric ratio (Vs/Vc) is at most 10, at most 8, at most 7, or at most 6.
Following withdrawal of a suitable volume of gas from container 102, controller 350 is configured to close valves 304 and 318, and to open valves 347, 348, and 312, to enable a second adsorption (or a re-adsorption) phase as described herein. At this stage, sampling from container 102 is complete, the container can be unsealed, such as by opening door 104, and the target object(s) may be removed from the container.
Following reorientation of valves 304, 318, 312 and 348, heating element 422 of sorbent chamber 306 may be activated or controlled to heat sorbent 406 so as to effect at least partial desorption of organic molecules adsorbed thereto. In some embodiments, heating is affected for at most 1 minute, at most 30 seconds, at most 20 seconds, at most 15 seconds, or at most 10 seconds, such that appreciable desorption from the surface of sorbent 406 transpires.
Subsequently or concurrently, controller 350 is configured to activate vacuum pump 326, such that the vapor is withdrawn from sorbent housing 400 via port 402 and conduits 307 and 344 into adsorption units 342.
The vapor passes through adsorption units 342, such that organic molecules that had been desorbed from sorbent 406 are now adsorbed by sorbents contained in adsorption units 342, resulting in one or more loaded sorbents. The vapor not adsorbed within adsorption units 342 is withdrawn from the columns via conduit 346 and valve 348 into liquid 320 of vessel 316. As mentioned hereinabove, the vapor bubbles up from liquid 320 into gas filled portion 324 of vessel 316, and from there is withdrawn by vacuum pump 326 via conduit 322 and is removed from the apparatus via exhaust pipe 328. In some embodiments, as the withdrawn vapor bubbles through liquid 320 and into gas filled portion 324 of vessel 316, any hazardous substances not adsorbed by sorbent 406 and still present in the withdrawn vapor are neutralized, oxidized, or otherwise deactivated by the neutralizing, oxidizing, or deactivating substance in liquid 320.
The volume of vapor passing through adsorption units 342 may be any suitable volume. However, it will be appreciated that the desorption from sorbent 406 may be carried out at a relatively high temperature and with a relatively small volume of vapor, with respect to the desorption occurring within container 102.
Thus, in some embodiments, controller 350 is configured to control vacuum pump 326 such that a first volume of the withdrawn gas delivered by the fluid transfer arrangement to the first sorbent is larger than a second volume of the gas sample delivered by the fluid transfer arrangement from the first sorbent to the second sorbent. A dimensionless volumetric ratio between the first volume and the second volume may be at least 2, at least 4, at least 8, or at least 12, and more typically, at least 20, at least 50, at least 100, at least 250, at least 500, or at least 1000.
Following transit of the vapor through adsorption units 342, the loaded sorbents are analyzed for detection of hazardous substances adsorbed thereto.
It must be emphasized that while high operating temperatures increase desorption of the adsorbed target compounds, such high temperatures may also appreciably increase the pyrolysis of these target compounds, which may reduce the available quantity of analyte below the Limit of Detection (LOD) of the sensor. This may result in misdetection, and may also exacerbate masking phenomena.
In some embodiments (e.g., for high affinity sorbents having a characteristically high target substance desorption temperature), it may be advantageous, therefore, to effect a short spike (or spikes) of heat to avoid pyrolysis. However, such heating may compromise the homogeneity of the heating regime, increasing local heating and local pyrolysis, and possibly detracting from the lifetime of the sorbent/adsorption surface. Such rapid heating may be particularly disadvantageous for large, thick sorbent mats, as the homogeneity of the heating distribution within the sorbent depends, inter alia, on the heater temperature distribution, the thermal conductivity of the sorbent material, and other physical and structure parameters of heating system.
Moreover, at any given temperature, the equilibrium concentration of target compound adsorbed onto the sorbent/adsorption surface may largely depend on the partial pressure of the target compound. It may be counterproductive, therefore, to utilize large adsorption surface areas (e.g., by using large quantities of sorbent) in an effort to appreciably reduce the partial pressure of the target compound in the adsorption chamber outlet.
Thus, while utilizing large sorbent areas appears attractive from various standpoints, the inventor has discovered that a balance exists, such that the size of the sorbent should effectively be limited. The inventor has further discovered that the quantity of analyte obtained by adsorption may be increased by recirculating the discharge or outlet stream from the first stage of adsorption to an earlier point in the process, e.g., to container 102, or to some point between the container and the first stage of adsorption, substantially as described hereinabove.
The inventor has discovered that such recirculation may obviate, or largely obviate the need for introducing fresh air upstream of the first adsorption stage, during the sampling process, thereby avoiding an appreciable reduction (dilution) in the target substance concentration in the inlet to the first adsorption stage, which may reduce the total quantity of adsorbed target substance, and in extreme cases, may actually desorb target substance already adsorbed on the adsorption surface of the first adsorption stage.
While sorbents having high affinity to the target substances are known, and have seen use, the inventor believes that the apparatus and methods described herein may be an advantageous alternative, for at least the following reason: such high-affinity sorbents may require appreciably higher temperatures of desorption, which may result in unacceptably high levels of pyrolysis.
In some embodiments, the loaded sorbents are removed from adsorption units 342 and are provided to a biosensor, such as a sniffing dog, for delivery of vapor thereto and for detection of hazardous substances by the biosensor. In some embodiments, the biosensor is disposed within a small distance, such as one meter, of the loaded sorbent, while the loaded sorbents are within adsorption units 342. It will be appreciated that in some embodiments, the biosensor may be disposed within a small distance, such as one meter, of sorbent housing 400, and sorbent housing 400 may be unsealed, such as by a window or shutter (not shown), to expose loaded sorbent 406 to the biosensor for delivery of vapor thereto.
In some embodiments, the loaded sorbents are removed from sorbent adsorption units 342 and are provided to an instrumental chemical detection system (not shown), such as, for example, a mass spectrometer.
In some embodiments, the apparatus may be adapted, and/or operated, so as to enable selective adsorption of gas-phase molecules that tend to desorb at high temperature, due to equilibrium and/or kinetic behavior. For example, various masking agents tend to desorb at lower temperatures than many of the hazardous or explosive substances of interest. The inventors have discovered that by maintaining sorbent 406 below a particular temperature, much of the masking agents adsorbed in sorbent 406 may be desorbed/driven off, leaving a higher ratio of adsorbed hazardous materials to masking agents in sorbent 406. Thus, the initial, lower-temperature desorption step may be performed while adsorption units 342 are disconnected from sorbent chamber 306, or while a particular adsorption unit of adsorption units 342 is connected to sorbent chamber 306, while at least a second adsorption unit of adsorption units 342 is disconnected from sorbent chamber 306. Subsequent to the initial, lower-temperature desorption step, the at least second adsorption unit of adsorption units 342 may be connected to sorbent chamber 306. Sorbent 406 may then be heated above the above- described particular temperature, such that a higher ratio (with respect to the initial ratio) of adsorbed hazardous materials to masking agents is desorbed from sorbent 406, and is adsorbed by second adsorption unit of adsorption units 342.
In some embodiments, sorbent 345 and/or adsorption units 342, may be subjected to preliminary cooling or freezing, prior to passing the desorbed vapors through conduit 344. The lower temperature may favor increased adsorption of these desorbed vapors.
Subsequently, the apparatus may be prepared for the next run. Before a new target object (e.g., a new pallet having a plurality of cartons or suitcases) is introduced to container 102, a post processing, or sterilization mode may be implemented. In this mode, container 102 is emptied of any objects contained therein (if such emptying has not yet transpired), and in some embodiments, container 102 remains unsealed so that gas from the ambient environment may enter the container. In some embodiments, the container may remain sealed or substantially sealed, until after the temperature in the container has risen to a minimum threshold temperature (e.g., 70°-80°C) for a minimum period (e.g., 30 seconds). In some embodiments, pumping arrangement 118 is fluidly disconnected from container 102 by closing valve 120, and/or adsorption and fluid transfer arrangement 110 is disconnected from container 102 by closing valve 304. In some embodiments, only recirculation loop 200 is operative during the sterilization mode, at least until the minimum threshold temperature has been achieved in container 102
In some embodiments, ventilator 106 is activated, and in some embodiments remains activated for the duration of the sterilization mode.
After container 102 has been substantially decontaminated, container 102 may be ventilated by recirculation pump or blower 210 withdrawing gas from container 102 so that fresh air may be introduced into container 102 through open door 104 or through another inlet. The gas withdrawn by recirculation pump may be removed from the apparatus via exhaust pipe 218 and (open) valve 220.
Subsequently, valve 220 and door 104 are closed, disconnecting recirculation loop 200 from the ambient environment. Recirculation pump 210 withdraws gas from container 102, the withdrawn gas is heated by heating element 212, and is reintroduced into container 102 via conduit 216 and inlet 204. This process is repeated until the inside volume of container 102 reaches a desired sterilization temperature and/or until a desired duration has passed.
It will be appreciated that the desired sterilization temperature and the desired sterilization duration may vary depending on the level of contamination of container 102, for example as detected by a biosensor during the sampling mode. In some embodiments, the sterilization temperature is at least 80°C, at least 90°C, at least 100°C, at least 150°C, at least 200°C, at least 250°C, or at least 300°C. In some embodiments, the sterilization duration is at least 30 seconds, at least 60 seconds, or at least 120 seconds, and typically less than 10 minutes, less than 7 minutes, or less than 5 minutes.
In some embodiments, following sterilization of container 102, the level of sterility of the container is tested, for example by carrying out a sampling cycle without inserting any object into container 102 or by swabbing a surface of the container 102 or of conduits of recirculation loop 200.
While various operations have been described as being controlled by a controller, it will be appreciated by those of skill in the art that such operations may be controlled by a human operator, or by a human operator having access to various system parameters (e.g., on a computer display).
As used herein in the specification and in the claims section that follows, the term "percent", or "%", refers to percent by weight, unless specifically indicated otherwise.
Similarly, the term "ratio", as used herein in the specification and in the claims section that follows, refers to a weight ratio, unless specifically indicated otherwise.
As used herein in the specification and in the claims section that follows, the term "fluidly communicating with", "fluidly associated with", "in fluid communication with", "in fluid flow communication with", and the like are meant to describe a state between two sections of an apparatus, when any intervening valves are in an at least partially open state.
As used herein in the specification and in the claims section that follows, the term "desorption" and the like refers to a process that is substantially the opposite from adsorption.
As used herein in the specification and in the claims section that follows, the term "neutralizing substance", and the like is meant to include an oxidizing substance.
As used herein in the specification and in the claims section that follows, the term "pore size" or "pore diameter" is determined according to a bubble test for pore size determination, ASTM F316-06 (2011). While the maximum pore size determined by this method may be about 15 microns, in determining the porosity in fibrous or packaging materials, the maximum pore size determined by this method may be about 250 microns (ASTM F2096).
It will be appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.
Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification, including U.S. Patent No. 6,324,927, are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

WHAT IS CLAIMED IS:
1. An apparatus for sampling and processing at least one target substance within a target volume, the apparatus comprising:
(a) a container having the target volume disposed therein;
(b) an adsorption arrangement, including a first adsorption stage and a second adsorption stage, said first adsorption stage having a first adsorption surface, said second adsorption stage including at least a second adsorption stage sorbent having at least a second adsorption surface, said first and second adsorption surfaces being adapted or selected to adsorb gas-phase molecules;
(c) a desorption arrangement functionally associated with said first adsorption stage and adapted to effect desorption of gas-phase molecules adsorbed onto said first adsorption surface; and
(d) a fluid transfer arrangement adapted and configured to:
(i) withdraw a first gas sample from within said container during a withdrawal mode;
(ii) deliver said first gas sample to said first adsorption surface, during a first sampling mode; and, subsequently,
(iii) deliver to said second adsorption surface, during a second sampling mode, a second gas sample containing gas phase molecules desorbed from said first adsorption surface.
2. The apparatus of claim 1, said container having minimum dimensions of 0.5 meters by 0.5 meters by 0.5 meters.
3. The apparatus of claim 1 or claim 2, at least one of said first and second adsorption surfaces having a characteristic pore diameter of at least 65 , at least 75μ, at least 85μ, at least 100μ, at least 125μ, at least 150μ, at least 200μ, or at least 300μ.
4. The apparatus of claim 3, said characteristic pore diameter being at most 3500 , at most 2000 , at most 1200μ, at most ΙΟΟΟμ, at most 900 μ, at most 750μ, at most 650μ, or at most 550μ.
5. The apparatus of claim 3 or claim 4, said characteristic pore diameter being within a range of 70 to 1500μ, 80 to 1500μ, 100 to 1200μ, 100 to 1000μ, 150 to 1200μ, 200 to 1200μ, 200 to 1000μ, 250 to 1200μ, 300 to 1200μ, 300 to 1000μ, 350 to 1000μ, 350 to 800μ, or 400 to 1000μ.
6. The apparatus of any one of claims 1 to 5, at least a portion of said first adsorption surface being disposed on a first adsorption stage sorbent.
7. The apparatus of any one of claims 1 to 6, at least one of a or the first adsorption stage sorbent and said second adsorption stage sorbent being temperature stable at a lower temperature limit of 0°C and up to an upper temperature limit of at least 70°C.
8. The apparatus of claim 7, said upper temperature limit being 85°C, 95°C, 110°C, 130°C, 150°C, 175°C, or 200°C.
9. The apparatus of any one of claims 1 to 8, further comprising a heating arrangement, adapted to heat said target volume.
The apparatus of claim 9, said heating arrangement including
(i) a recirculation loop attached to said container to form an outlet for withdrawing said gas from said container, and an inlet for returning said gas to said container;
(ii) a recirculation pump, fluidly associated with said loop, and adapted to effect forced circulation of said gas by withdrawing said gas via said outlet and returning said gas to said container via said inlet; and
(iii) a heating arrangement, associated with said loop, and adapted to heat said gas as said gas transits said recirculation loop.
11. The apparatus of claim 10, said recirculation pump and said heating arrangement controlled such that said gas reintroduced to said container via said inlet has a temperature that exceeds a bulk temperature within said container by at most 40°C, at most 35°C, at most 30°C, at most 25 °C, at most 20°C, at most 15°C, or at most 10°C.
12. The apparatus of any one of claims 1 to 11, said container being sealed, during said gas withdrawal mode, from an ambient environment.
13. The apparatus of any one of claims 1 to 12, further comprising a pumping arrangement, fluidly associated with said container, and adapted to introduce an external gas to said container.
14. The apparatus of claim 13, said pumping arrangement adapted and positioned such that said external gas includes, or consists essentially of, ambient air.
15. The apparatus of any one of claims 1 to 14, at least one of a or the first adsorption stage sorbent and said second adsorption stage sorbent b having a specific surface area within a range of 0.1 to 50 m2/gram.
16. The apparatus of any one of claims 1 to 15, wherein any filtration arrangement for filtering said gas from within said container is disposed downstream of said adsorption arrangement, so as to receive a portion of said gas after said portion has been discharged from said adsorption arrangement.
17. The apparatus of any one of claims 1 to 15, wherein at least one of a first gas flow path between said container and said first adsorption stage, and a second gas flow path between said first and second adsorption stages, is free of any gas filtration arrangement.
18. The apparatus of any one of claims 1 to 17, further comprising a ventilating arrangement having a ventilator disposed within said container, and adapted, in a ventilation mode, to mix said gas within said container.
19. The apparatus of any one of claims 1 to 18, said container being semirigid, at least semi-rigid, or rigid.
20. The apparatus of any one of claims 1 to 19, further comprising a controller, said controller configured to control said fluid transfer arrangement.
21. The apparatus of claim 20, said controller configured to control said fluid transfer arrangement to periodically attain a sub-atmospheric pressure within said container, during a single sampling run.
22. The apparatus of claim 20, said controller configured to control said fluid transfer arrangement to periodically attain a super-atmospheric pressure within said container, during a single sampling run.
23. The apparatus of claim 20, said controller configured to control said fluid transfer arrangement to periodically attain, within said container, a sub- atmospheric pressure, and a super-atmospheric pressure, during a single sampling run.
24. The apparatus of any one of claims 20 to 23, said controller further configured to maintain a maximum pressure within said container below 1.5 atmosphere absolute (ata), below 1.4 ata, below 1.3 ata, below 1.25 ata, below 1.2 ata, below 1.15 ata, or below 1.1 ata.
25. The apparatus of any one of claims 20 to 24, said controller further configured to control said fluid transfer arrangement to effect at least one operating cycle within a sampling run, wherein, in each cycle of said at least one operating cycle, said container undergoes pressurization from a sub -atmospheric pressure state to a super-atmospheric pressure state.
26. The apparatus of claim 25, said super-atmospheric pressure state including a peak pressure state, and said sub-atmospheric pressure including a peak vacuum state, said controller further configured to control said fluid transfer arrangement such that said pressurization from said peak vacuum state to said peak pressure state, or vice versa, within a single cycle of said operating cycle, is achieved over a period of at least 1 second, at least 2 seconds, at least 5 seconds, at least 10 seconds, or at least 20 seconds.
27. The apparatus of claim 25, said super-atmospheric pressure state including a peak pressure state, and said sub-atmospheric pressure including a peak vacuum state, said controller further configured to control said fluid transfer arrangement such that a transient pressure gradient (dP/dt) within said container is maintained below 1,000 Pa/s, or within a range of 100 to 1,000 Pa/s, 150 to 1,000 Pa/s, 200 to 1,000 Pa/s, 300 to 1,000 Pa/s, 400 to 1,000 Pa/s, or 200 to 800 Pa/s, within at least one cycle of said operating cycle.
28. The apparatus of any one of claims 20 to 27, said controller further configured to control said fluid transfer arrangement such that a first volume of said first gas sample delivered by said fluid transfer arrangement to said first adsorption stage is larger than a second volume of said second gas sample delivered by said fluid transfer arrangement from said first adsorption stage to said second adsorption stage, a dimensionless volumetric ratio between said first volume and said second volume being at least 2, at least 4, at least 8, at least 20, at least 50, at least 100, at least 250, at least 500, or at least 1000.
29. The apparatus of any one of claims 20 to 28, said container having a total volume Vc, said controller further configured to control said fluid transfer arrangement such that a dimensionless volumetric ratio of a sampling volume (Vs) of said first gas sample to said first adsorption surface, to said total volume (Vc), is at least 0.1, at least 0.2, at least 0.3, at least 0.5, at least 1, at least 2, at least 3, at least 4, or at least 5.
30. The apparatus of claim 29, said volumetric ratio (Vs/Vc) being at most 10, at most 8, at most 7, or at most 6.
31. The apparatus of any one of claims 1 to 30, said controller further configured to initiate a sterilization mode within the apparatus, following said sampling mode, said sterilization mode including heating an internal volume of said container, using at least one heating arrangement, to at least 70°C, at least 85°C, at least 100°C at least 150°C, at least 200°C, at least 250°C, or at least 300°C.
32. The apparatus of any one of claims 1 to 31, at least one of a or the first adsorption stage sorbent and said second adsorption stage sorbent including, largely including, or consisting essentially of a sorbent fabric.
33. The apparatus of claim 32, said sorbent fabric including, largely including, or consisting essentially of a material selected from the group consisting of rayon fiber and fiberglass.
34. The apparatus of any one of claims 1 to 31, a or the first adsorption stage sorbent including, largely including, or consisting essentially of sorbent granules.
35. The apparatus of any one of claims 1 to 34, said adsorption arrangement including a first sorbent housing having a or the first adsorption stage sorbent disposed therein and including a sealed chamber having at least a first port and a second port, said ports fluidly intercommunicating via said chamber, and via the first adsorption stage sorbent.
36. The apparatus of claim 32 or claim 33, at least one of said first and second adsorption stage sorbents including said sorbent fabric, a compressive strength of said sorbent fabric being at most 3MPa, at most l .OMPa, at most 0.5MPa, at most 0.3MPa, at most 0.2MPa, at most O. lMPa, at most 0.05MPa, or at most 0.02MPa.
37. The apparatus of claim 34, at least one of said first and second adsorption stage sorbents including said sorbent granules, a compressive strength of said sorbent granules being at most lOMPa, at most 5MPa, at most 2MPa, at most IMPa, at most 0.5MPa, at most 0.2MPa, at most 0. IMPa, or at most 0.05MPa.
38. The apparatus of any one of claims 1 to 37, further comprising a detection arrangement adapted to receive said second adsorption stage sorbent.
39. The apparatus of any one of claims 1 to 38, said desorption arrangement including a heating arrangement.
40. The apparatus of any one of claims 1 to 39, further comprising a first adsorption stage recirculation loop, the apparatus adapted and configured wherein, during at least a portion of said first sampling mode, at least a portion of said first gas sample discharged from said first adsorption stage is recirculated via said first adsorption stage recirculation loop, to an upstream position within the apparatus.
41. The apparatus of claim 40, said upstream position being within said container.
42. The apparatus of claim 41 or claim 42, said upstream position being downstream from said container.
43. A method of said sampling and processing of the at least one target substance within the target volume, the method comprising:
(a) providing the apparatus according to any one of claims 1 to 37 A;
(b) sampling said container to produce said first gas sample;
(c) contacting said first gas sample with said first adsorption surface to produce a first loaded adsorption surface, which optionally is at least partially disposed on a first loaded sorbent;
(d) subsequently desorbing material adsorbed to said first adsorption surface to produce said second gas sample containing said gas phase molecules; and
(e) contacting said second gas sample, with said second adsorption surface, to produce at least a second loaded sorbent.
44. The method of claim 43, further comprising exposing at least one of said first loaded sorbent and said second loaded sorbent to deliver vapor to a biosensor.
45. The method of claim 44, said biosensor being, or including, a sniffing dog.
46. The method of claim 44 or claim 45, further comprising disposing said biosensor within one meter of at least one of said first loaded sorbent and said second loaded sorbent.
47. The method of any one of claims 43 to 46, further comprising delivering said second loaded sorbent to deliver vapor to an instrumental chemical detection system.
48. The method of any one of claims 43 to 47, a maximum pressure differential across said first adsorption surface, during said contacting of said sample therewith, being less than 1,000 Pa, less than 800 Pa, less than 600 Pa, less than 500 Pa, less than 400 Pa, less than 300 Pa, less than 200 Pa, less than 150 Pa, or less than 100 Pa.
49. The method of any one of claims 43 to 47, said sampling of said container to produce a first gas sample being effected within 3 minutes, within 2.5 minutes, within 2 minutes, within 1.5 minutes, or within 1 minute, while maintaining a maximum pressure differential across said first adsorption surface, during said contacting of said sample therewith, below 1,000 Pa, below 800 Pa, below 600 Pa, below 500 Pa, below 400 Pa, below 300 Pa, below 200 Pa, below 150 Pa, or below 100 Pa.
50. The method of claim 49, said first gas sample having a volume of at least 0.1m3, at least 0.2m3, at least 0.3m3, at least 0.5m3, at least 0.7m3, at least lm3, at least 1.5m3, at least 2m3, at least 3m3, or at least 5m3.
51. The method of any one of claims 43 to 50, further comprising, subsequent to step (e), heating said container to at least 70°C, at least 85°C, at least 100°C at least 150°C, at least 200°C, at least 250°C, or at least 300°C, so as to desorb or otherwise remove any of said at least one target substance disposed within said container.
52. The method of any one of claims 38 to 45, further comprising, subsequent to step (e), heating said container to a temperature within a range of 70°- 250°C, 70°-200°C, 70°-150°C, or 85°-200°C, so as to desorb or otherwise remove any of said at least one target substance disposed within said container.
53. The method of any one of claims 43 to 52, the target substance including at least one hazardous substance.
54. The method of claim 53, said hazardous substance including at least one of trinitrotoluene (TNT) and an explosive nitramine compound.
55. The method of any one of claims 43 to 54, said desorbing of said material adsorbed to said first adsorption surface being performed in at least first and second time periods, said second time period being subsequent to said first time period, wherein, in said first time period, said desorbing is effected at a first temperature, and in said second time period, said desorbing is effected at a second temperature, and wherein said second temperature exceeds said first temperature.
56. The method of claim 55, wherein at least a fraction of gas desorbed during said first time period is diverted from contacting said second adsorption surface.
57. The method of claim 55 or claim 56, wherein said at least a second sorbent includes a first sorbent unit and a second sorbent unit, and wherein at least a fraction of gas desorbed during said first time period is contacted with said second adsorption surface of said first sorbent unit, and at least a fraction of gas desorbed during said second time period is contacted with said second adsorption surface of said second sorbent unit.
58. The method of claim 55 or claim 56, wherein said at least a second sorbent includes a first sorbent unit and a second sorbent unit, and wherein at least a fraction of gas desorbed during said first time period is contacted with said second adsorption surface of said first sorbent unit, and at least a fraction of gas desorbed during said second time period is contacted with said second adsorption surface of said second sorbent unit, so as to improve chemical selectivity or reduce a concentration of masking agents in said second sorbent unit.
PCT/IB2015/054802 2014-06-25 2015-06-25 Apparatus for sampling chemical substances, and methods therefor WO2015198272A1 (en)

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