Sample retrieval device for aerosol collection

• US 6,854,344 B2
• Filed: 12/04/2003
• Issued: 02/15/2005
• Est. Priority Date: 12/19/2002
• Status: Expired due to Fees

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Gick, Frederick P., Cornish, Timothy J.
• Primary Examiner(s): RAEVIS, ROBERT R
• Application Number:
  US10/728,297
• Publication Number:
  US 20040118222A1
• Time in Patent Office: 439 Days
• Field of Search: 73/280.1, 73/280.2, 73/280.4, 73/280.5, 73/280.6, 738/632.2, 738/632.3, 738/633.1, 738/633.3, 738/643.1, 738/648.1, 738/643.3, 738/643.4, 738/647.3
• US Class Current: 73/863.22
• CPC Class Codes: G01N 1/2202 involving separation of sample components during sampling
• CPC Class Codes: G01N 1/2252 in a vehicle exhaust
• CPC Class Codes: G01N 1/24 Suction devices G01N1/22 - G01N1/2294 take precedence
• CPC Class Codes: G01N 2001/2223 aerosol sampling devices
• CPC Class Codes: H01J 49/04 Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components

Abstract

A modular aerosol sample detection system is provided comprising a sample collector couplable to an aerial vehicle and provided with at least one retrievable collection sample plate, which controllably rotates to collect aerosol samples on a multiplicity of collection spots arranged in multiple concentric tracks on the collection disk, and a multi-channel TOF removably couplable to the collection sampler to analyze the collected samples.

Claims

1. An aerosol sample detection system comprising:

a sample collector removably attachable to a vehicle and comprising;

a housing having an interior;

a plurality of passages formed in the housing and configured to simultaneously provide multiple flows of aerosol sample into the interior thereof from ambient; and

,

a sample plate removably mounted in the interior of the housing downstream of the plurality of passages and having a sample surface, which is juxtaposed with the plurality of passages, the sample plate and the plurality of passages being displaceable relative to one another so that multiple concentric tracks of collection spots of the aerosol sample are formed on the sample surface upon impacting the multiple flows of the aerosol sample thereagainst; and

a multi-channel time of flight (TOF) mass analyzer provided with multiple channels and configured to receive the sample plate, wherein when the sample plate is removed from the sample collector and loaded into the mass analyzer, the multiple concentric tracks on the sample surface each are indexed through a respective one of multiple channels of the TOF mass analyzer.

2. The aerosol sample detection system of claim 1, further comprising a pressure source mounted in the housing downstream from the sample plate and including a fan or a pump to provide pressure differential between the interior of the housing and the ambient, which is sufficient to force air along the plurality of passages into the interior of the housing.

3. The aerosol sample detection system of claim 2, wherein the housing has a modular configuration extending along a symmetry axis and including a base configured to house the pressure source spaced axially downstream of the sample plate, an intermediary air intake part of the housing provided with the plurality of passages and covering the sample surface, and a cover topping the intermediary air intake part, wherein the base, the intermediary air intake part and the cover coextend with one another in a plane perpendicular to the symmetry axis and are detachably coupled to one another.

4. The aerosol sample detection system of claim 3, wherein the base of the housing is provided with multiple air outlets and has a recessed surface shaped and dimensioned to receive the sample plate.

5. The aerosol sample detection system of claim 4, wherein the intermediary air intake part of the housing has a lower flat surface covering the recessed surface of the base and an upper surface having a flat bottom spaced from the lower flat surface and a pair of flanges spaced across the flat bottom and extending axially upwards therefrom.

6. The aerosol sample detection system of claim 5, wherein the cover abuts the pair of flanges and is provided with at least one spacer extending axially toward and pressing against the flat bottom, the at least one spacer being dimensioned to form a pair of air channels defined between the at least one spacer and a respective one of the pair of flanges.

7. The aerosol sample detection system of claim 5, wherein the pair of flanges each have a respective cutout region extending laterally inwards toward the cutout region of the other flange and traversed by a respective one of the plurality of passages leading into the recessed surface of the base and terminating upstream of the sample surface of the sample plate.

8. The aerosol sample detection system of claim 7, wherein the cutout regions each have a respective substantially triangular shape and is provided with a respective apex spaced from the symmetry axis and located next to an intake port, which is formed in each of the cutout regions and is in flow communication with a respective one of the plurality of the passages traversed by the aerosol sample.

9. The aerosol sample detection system of claim 8, wherein the cutout regions are non-uniformly dimensioned to have the apexes thereof spaced asymmetrically relative to the symmetry axis.

10. The aerosol sample detection system of claim 1, further comprising a drive mounted in the housing and removably coupled to the sample plate rotatable so that the plurality of passages each have a respective downstream outlet port facing the sample surface and controllably juxtaposed with the collection spots of the multiple concentric tracks.

11. The aerosol sample detection system of claim 10, wherein the drive is a stepper motor coupled to the sample plate.

12. The aerosol sample detection system of claim 11, wherein the sample plate is disk-shaped and is rotatably fixed to a shaft of the stepper motor.

13. The aerosol sample detection system of claim 11, wherein the sample surface is indexed through the collection spots of the concentric tracks by the stepper motor to allow numerous collections of the aerosol sample to be performed during displacement of the sample plate and the plurality of passages relative to one another.

14. The aerosol sample detection system of claim 10, wherein the sample plate has a plurality of groups of spaced apart ventilation holes, each group of ventilation holes being arranged to surround a respective one of the collection spots of each of the concentric tracks on the sample surface of the sample plate.

15. The aerosol sample detection system of claim 1, wherein the sample surface includes a substrate selected from the group consisting of charcoal or adhesives.

16. The aerosol sample detection system of claim 1, wherein the plurality of passages extend substantially parallel to one another and are spaced asymmetrically relative to a symmetry axis of the housing to provide parallel multiple flows of aerosol sample through the housing.

17. The aerosol sample detection system of claim 1, wherein the sample surface is made from a micro-porous material including flit or filter configured to trap particulates entrained in the aerosol sample.

25. The aerosol sample detection system of claim 10, wherein the collection spots of each of the multiple concentric tracks are spaced uniformly from one another at a respective angular distance, the uniform angular distance between the collections spots of one of the multiple concentric tracks being different from the uniform angular distance between the collection spots of another one of the multiple concentric tracks.

26. The aerosol sample detection system of claim 10, wherein the collection spots of the multiple concentric tracks are arranged to have each of the collection spots of one of the multiple concentric tracks aligned with and spaced across the sample plate from a respective collection spot of another one of the concentric tracks, wherein the aligned and spaced apart collections spots of the concentric tracks are impinged simultaneously by the multiple flows of aerosol sample exiting the outlet ports of the plurality of passages to allow for redundancy in collection of the aerosol sample on the sample surface of the sample plate.

18. An aerosol sample detection system comprising:

a radio controlled unmanned aerial vehicle (RC UAV) having;

a plurality of rotary blades each powered by a battery set; and

a control panel spaced equidistantly from the plurality of rotary blades; and

,

an aerosol collector removably mounted to the control panel and operative to collect multiple aerosol samples, the aerosol collector comprising;

a housing having an interior and an axis of symmetry;

a plurality of passages formed in the housing and spaced asymmetrically with respect to the axis of symmetry;

a sample plate rotatable about the axis of symmetry and removably mounted in the interior of the housing downstream of the plurality of passages, the sample plate having a sample surface juxtaposed with the plurality of passages;

a fan, mounted in the housing downstream from the sample plate, that draws multiple flows of aerosol sample from ambient through the plurality of asymmetric passages and toward the sample surface; and

a stepper motor mounted in the housing and configured to rotate the sample surface about the axis of symmetry such that the multiple flows of aerosol sample impact the sample surface as it rotates so as to form multiple separated concentric circular tracks of collection spots thereon, the circular concentric tracks having (i) their respective centers coinciding with the axis of symmetry, and (ii) different respective radii.

19. The aerosol detection system of claim 18, further comprising a time of flight (TOF) mass analyzer configured to receive the sample plate and provided with multiple channels, wherein when the sample plate is removed from the sample collector and loaded into the mass analyzer, the multiple concentric tracks formed on the sample surface of the sample plate each are indexed through a respective one of the multiple channels of the TOF mass analyzer.

20. A method of detecting an aerosol sample comprising the steps of:

mounting an aerosol collector to a radio-controlled unmanned aerial vehicle, said mounting step comprising the further steps of;

providing a housing centered along a symmetry axis;

providing a plurality of passages extending through the housing and configured to simultaneously guide multiple flows of the aerosol sample through the housings and asymmetrically with respect to the symmetry axis;

removably placing a sample plate within the housing so that a sample surface of the sample plate opposes downstream ends of the plurality of passages; and

,

rotating the disk during a flight of the aerial vehicle about the symmetry axis and relative to the plurality of passages; and

creating a negative pressure within the aerosol collector, wherein said negative pressure causes the multiple flows of the aerosol sample to impact the rotating sample surface so as to form multiple separated concentric circular tracks of collection spots thereon, the circular concentric tracks having (i) their respective centers coinciding with the symmetry axis, and (ii) different respective radii.

21. The method of claim 20, further comprising the steps of:

removing the sample plate from the housing; and

,

loading the sample plate into a time of flight (TOF) mass analyzer provided with multiple channels, wherein the multiple concentric tracks each are indexed through a respective one of the multiple channels of the TOF mass analyzer.

22. The method of claim 21, wherein the step of loading comprises the step of redundantly assessing the aerosol sample collected on a group of spaced across the sample plate collection spots of the multiple concentric tracks.

23. The method of claim 20, wherein the step of rotating is provided in a time- and speed-controlled manner, thereby indexing each collection spot of the multiple concentric tracks, the method further comprising the step of continuously powering the sample collector during a flight of the radio-controlled unmanned aerial vehicle.

24. An aerosol collector comprising:

a housing having an interior and an axis of symmetry;

a plurality of passages formed in the housing and spaced asymmetrically with respect to the axis of symmetry;

a sample plate rotatable about the axis of symmetry and removably mounted in the interior of the housing downstream of the plurality of passages, the sample plate having a sample surface juxtaposed with the plurality of passages;

a fan, mounted in the housing downstream from the sample plate, that draws multiple flows of aerosol sample from ambient through the plurality of asymmetric passages and toward the sample surface; and

a stepper motor mounted in the housing and configured to rotate the sample surface about the axis of symmetry such that the multiple flows of aerosol sample impact the sample surface as it rotates so as to form multiple separated concentric circular tracks of collection spots thereon, the circular concentric tracks having (i) their respective centers coinciding with the axis of symmetry, and (ii) different respective radii.