Air sampling system
10746634 ยท 2020-08-18
Inventors
Cpc classification
B64U2101/00
PERFORMING OPERATIONS; TRANSPORTING
B64U2101/35
PERFORMING OPERATIONS; TRANSPORTING
B64U10/16
PERFORMING OPERATIONS; TRANSPORTING
B64C39/024
PERFORMING OPERATIONS; TRANSPORTING
B64D1/00
PERFORMING OPERATIONS; TRANSPORTING
B64U50/13
PERFORMING OPERATIONS; TRANSPORTING
International classification
G01N33/00
PHYSICS
B64D1/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
An atmosphere sampling system includes: an unmanned rotary-wing aircraft platform including: an airframe capable of lifting a selected payload mass; at least one motorized rotor; and, a flight control system including an on-board controller; an atmosphere sampling unit having a total mass no greater than the selected payload mass, and including: a blower preferably having backward-facing blades, an inlet structure to draw in air to be sampled, and an outlet to discharge air after sampling; a plurality of sample containers; and, an indexing mechanism to move selected sample containers, one at a time, into contact with the inlet structure so that samples may be collected; and, a power supply with sufficient capacity to operate the motorized rotor(s), the onboard portion of the flight controller, the blower, and the indexing system.
Claims
1. An atmosphere sampling system comprising: an unmanned rotary-wing aircraft platform comprising: an airframe capable of lifting a selected payload mass; at least one motorized rotor; and, a flight control system including an on-board controller; an atmosphere sampling unit having a total mass no greater than said selected payload mass, and comprising: a centrifugal blower having blades of a selected orientation, an inlet structure to draw in an atmosphere to be sampled, and an outlet to discharge said atmosphere after sampling; a plurality of sample containers, each having a sample collecting medium therein; and, an indexing mechanism to move selected sample containers, one at a time, into contact with said inlet structure so that samples may be collected on said sample collecting medium; and, a power supply with sufficient capacity to operate said at least one motorized rotor, said onboard controller, said centrifugal blower, and said indexing mechanism.
2. The system of claim 1 wherein said flight control system includes said on-board controller in radio communication with a ground-based control station.
3. The system of claim 1 wherein said flight control system is preprogrammed to autonomously follow a selected route and a selected sample collection schedule.
4. The system of claim 1 wherein said flight control system records geolocation data associated with each sample, so that each sample may be identified with a specific collection location.
5. The system of claim 1 wherein said power supply includes a voltage regulator.
6. The system of claim 5 wherein said voltage regulator is positioned proximate to the outlet of said blower so that air flow from said blower will remove heat from said voltage regulator.
7. The system of claim 1 wherein said sample containers are held in a generally circular carousel that is rotatable by said indexing mechanism in order to bring a selected sample container into position for sample collection.
8. The system of claim 1 wherein said sample containers are held in a plate that is movable by said indexing mechanism in two orthogonal directions to bring a selected sample container into position for sample collection.
9. The system of claim 1 wherein said sample containers are loaded single-file in a magazine and are moved in a stepwise manner within said magazine by said indexing mechanism in order to bring a selected sample container into position for sample collection.
10. The system of claim 1 further including at least one sensor selected from the group consisting of: chemical sensors, combustible gas sensors, CO sensors, hydrogen sensors, thermal sensors, hydrogen sulfide sensors, optical sensors, video cameras, microphones, IR detectors, UV detectors, optical particulate detectors, and radiation sensors.
11. The system of claim 1 wherein said centrifugal blower comprises backward-facing blades.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting features illustrated in the drawing figures, wherein like numerals (if they occur in more than one view) designate the same elements. The features in the drawings are not necessarily drawn to scale.
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DETAILED DESCRIPTION OF THE INVENTION
(21) In its most general sense, the invention comprises a small unmanned aircraft platform carrying an air sampling system, including multiple sampling cartridges, or a single testing chamber, that can fly from one selected sampling location to another, either autonomously or under remote control, and return the sample cartridges for later analysis or collect data in flight for later analysis. Various aspects of the invention will be described in more detail in the exemplary materials that follow.
Example
(22) Unmanned Aircraft System One suitable sUAS-based delivery system, illustrated schematically in
(23) The invention may further include a companion computer, which is a device that travels on board the sUAS and allows developers to create powerful applications, using onboard computing, that communicates with the flight controller. Companion computers typically run computation intensive programs or time-sensitive tasks such as intelligent path planning, computer vision, and 3D modeling. Companion computers can also add the benefit of running additional sensors or actuators that cannot be controlled through the flight controller. An alternative approach would be to process the information at the ground control station or cloud then resend the computed information back to the drone while stationary or inflight. The user can select the most appropriate computational approach depending on routine engineering considerations such as mission time, complexity, on-board computing capacity, and data processing requirements.
(24) As used herein, the term flight controller is intended broadly to include any of the following: on-board data processors, companion computers, and cloud or ground control computer processing, as the geolocation data could be recorded in any of these locations.
Example
(25) The sUAS described above has a flight time of roughly 32 minutes (20% of battery remaining) when hovering out of ground effect with zero payload. The sUAS has a mass of roughly 9 kg and can carry a maximum payload of 12.7 kg. The flight endurance at gross weight was not determined.
Example
(26) Air sampler An air sampler,
(27) The goal for the sampler design was to have a high flow rate while maintaining a high static pressure to be able to move the air across the sampling cartridge. Applicant recognized that the main limiting factor to the design was weight followed by power consumption. Weight is the main limiting factor because the sUAS, as described above, uses roughly 120 watts/kg to hover even if the blower is not operating. Developing a light weight sampler was therefore crucial in order to have a sUAS that could have a long endurance and be able to lift the payload.
(28) The power consumption needed to be limited because the lightweight electronics needed to run the centrifugal blower become extremely limited above 10 A for off the shelf components. Also, all sUAS applications must consider the current required by the blower in order to keep the current within the specified current that the battery can discharge safely, and within the voltage regulator specifications, if applicable. The current the battery can safely discharge is in turn dependent on the battery specification (make, cells, voltage, type, etc.).
(29) The target time per air sample was roughly 1 minute which would require a volume of 150 liters to flow through the sample cartridge [mTrap, Assured Bio Labs, 228 Midway Lane, Suite B, Oak Ridge, Tenn.].
(30) Fan and Blower Considerations
(31) The baseline samplers in the mold industry are piston-type positive displacement compressors. Two examples of the baseline pump are: 1) Environmental Monitoring Systems' MegaLite IAQ Pump, which has a flow rate of 30 liters per minute (LPM) with a mass of 2.5 kg and is powered at 115 V and 0.46 A; and 2) Zefon's Z-Lite IAQ Air Sampling Pump, which has a flow rate of 30 LPM with a weight of 3.6 kg. When a technician is sampling with these types of pumps they take roughly 5 minutes to collect a sample when sampling at 30 LPM, assuming a sample of 150 liters is needed for the mTrap cartridge. The heavy weight of 2.5-3.6 kg for these two examples would significantly reduce the sUAS flight time for the air frame and power supplies described in the previous example. The low throughput of these two candidates ruled out the industry standard for sUAS applications since the sUAS has a flight time of roughly 32 minutes down to 20% battery remaining. The low throughput would not allow enough samples to be taken per flight for sampling to be cost effective over large areas.
(32) Based on the fact that positive displacement pumps were deemed to adversely limit performance, Applicant undertook research into axial fan designs because of their high flow rate and relatively low power consumption. Applicant quickly discovered that such axial fans are considered generally unsuitable for use as a vacuum pump. What this means is that fans are traditionally designed to operate with the inlet open to the atmosphere, i.e., with no restriction or pressure drop at the inlet side, and to provide flowing air at the outlet side. Applicant, by contrast, sought to place the sampling cartridge, i.e., the flow restriction, on the inlet side of the fan and thereby utilize a blower as a suction pump and not as it was intended to be used. The sampling cartridge needed to be placed on the inlet side of the pump to reduce the risk of preexisting contaminants inside the pump housing from contaminating the sample, which would give a false reading.
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Example
(34) The first attempt to adapt an axial fan,
(35) Applicant postulated that a centrifugal blower in backward facing blades,
Example
(36) The first centrifugal blower with backward facing blade to be selected for trial was the Model BFB04512HD [Delta Electronics, 252 Shang Ying Road, Kuei San Industrial Zone, Taoyuan Shien, Taiwan], which is a backward facing blade design that does not have a shroud connected to the blades. According to the manufacturer's specifications it is capable of flowing 138.8 liters per minute (LPM) and a static pressure of 9.3 mm H.sub.2O. The power consumption is 12V at 0.1 A.
(37) Applicant inquired with the manufacturer for information on the performance of the aforementioned blower when configured to be run as a suction device (i.e., with a restriction on the intake side and the outlet free to ambient air) and was advised by the manufacturer that our blowers cannot be run as a vacuum.
Example
(38) Despite the manufacturer's recommendation to the contrary, Applicant fitted the BFB0512HD blower to the sample cartridge, and discovered, surprisingly, that it achieved a flow rate of 1.3 LPM. This was a drastic improvement over the Corsair axial flow fan, providing a larger flow rate with a lower power consumption.
(39) Based on this discovery that a blower could be adapted to the sampling problem, Applicant began testing different blower designs and configurations.
Example
(40) To maximize the efficiency of the centrifugal blower, the backward facing blades were equipped with a completely enclosed shroud 121 attached to the blades on one side and open on the other as shown generally in
Example
(41) Several additional features of the blower 11 are shown schematically in
Example
(42) One application for the invention is for sampling airborne mold. For this task, the sampler was configured to use a cartridge as generally described in U.S. Pat. No. 9,170,178. One suitable cartridge is Assured Bio Labs mTrap. The mTrap works by capturing pathogens or particulates by blowing the atmosphere across a filter.
(43) It will be appreciated that many other air sampling problems exist, for which the invention may be adapted by using other kinds of sample cartridges. For example, a cartridge containing gold or copper wool could be used to collect airborne mercury vapor for monitoring emissions from mines, power plant stacks, and other potential sources of elemental Hg emissions. Activated carbon could be used to capture radon or various chemicals, particularly organics. Air sampling around cooling towers could be used to detect not only mold but also very fine water droplets for analysis to detect Legionella or other pathogenic microbes. Furthermore, filtration per se, is not the only means to capture a sample; inertial impaction or deposition onto a tacky or adhesive surface may also be used, as, for example, in the Air-O-Cell sampling cassette (Zefon International, Inc., 5350 SW 1st Lane, Ocala, Fla. 34474). Other means of sample collection can include sedimentation, impingement, impaction, slit-to-agar impactors, sieve impactors, centrefugil impactors, and membrane filtration. The skilled artisan may adapt the invention to such applications and variants using routine experimentation.
(44) As noted previously, a typical mission is contemplated to consist of maneuvering the sUAS into position at selected places that define a sampling pattern, keeping the sUAS in each place while drawing a predetermined amount of air through one sample cartridge, then indexing to another cartridge and moving to another place, and so on until the entire supply of cartridges has been filled with samples, then returning to base so that the cartridges can be removed for analysis. The steps of the method are shown schematically in
Example
(45) One suitable method for accommodating multiple samples is a circular carousel, as shown generally in
Example
(46) The sUAS can be controlled manually by a ground station or handheld radio transmitter 15 or programmed before launch so that the entire mission can be conducted autonomously. The ground station consists of two parts that can be run simultaneously or independently, the handheld transmitter and/or application running on a laptop or other device. The handheld ground control requires full manual control of the sUAS to conduct a flight and requires the operator to have existing sUAS experience. Using the handheld ground control however does not require the use of GPS since the aircraft is being flown visually within line of sight. The application on a laptop or other device does not require any sUAS experience, it does however require the use of a GPS. The pilot operates the sUAS from the laptop by clicking on commands in the application and clicking on locations on a downloaded map to fly to a given waypoint at a given altitude. Both the handheld and laptop parts of the ground station send telemetry on independent radio frequencies, some of the information includes battery voltage, power consumed, altitude, ground speed and distance from home location. The sUAS can fly fully autonomously without the use of a ground station after it is launched, even though contact with a ground station is recommended, by uploading data to the flight controller before launch. The flight plan is created in the application by setting a home location, waypoints, actions at waypoints, takeoff actions, and landing actions. The flight plan data is then transferred to the sUAS via a USB cable or a radio modem and stored on the flight controller memory.
(47) It will be understood that Applicant's use of the term autonomously simply implies that the sUAS is navigating from place to place without the real-time intervention of a ground controller. The skilled artisan will be aware that terminology in the field may vary, e.g., some authors distinguish between semi-autonomous navigation, which they regard as somewhat blindly following a preprogrammed path, versus fully autonomous navigation in which the vehicle has the ability to observe and adapt to its environment, for instance recognizing and maneuvering around obstacles that are encountered unexpectedly. Any of these operational variants are considered to be within the scope of the present invention.
Example
(48) Comparing the air flow diagram,
Example
(49) Each sampling cartridge 10 is preferably fixed with a unique identifier (typically a serial number, barcode, or RFID tag). When the sampling cartridge is loaded onto the sampling revolver the pilot logs the cartridge's specific position in the rotary cartridge holder 14. Once the drone is airborne and collecting the geographical location through the GPS or other geolocation means, a sample is taken by activating the blower. The unique identifier is then used to reference which sample was collected at the given geographical location. The sample is then sent to the lab for analysis and the information that is recorded is entered into a database which correlates the geolocation and lab information.
Example
(50) Future designs using a magazine style cartridge would reduce the amount of potential error from manually recording the position of the sampling cartridge on the revolver and the possibility of indexing the incorrect cartridge on the revolver. The magazine design also reduces the amount of samples that need to have a unique identifier since only an identifier would be needed on the magazine 41 or 41 to identify it with a particular mission. In other words, the testing lab could supply the entire loaded cartridge or carousel as a single unit, and the user would return the entire unit to the testing lab, where it would be automatically unloaded, tested, and reloaded with new cartridges. The magazine design also reduces the chance of cross contamination from ground contaminants being disturbed from the rotor wash or while the operator is installing/removing the sampling cartridges.
(51) It will be appreciated that magazines may exploit spring tension to perform the physical work of moving from one cartridge to the next. Such an approach has the further benefit of potentially reducing system mass and power requirements, because motors might be eliminated and battery draw can be reduced, as the spring can be preloaded before the flight begins and the stored mechanical energy replaces energy that otherwise would have been supplied by the battery.
Example
(52) It will be appreciated that when a sUAS is operating completely autonomously, following a preprogrammed flight plan, there is the danger that obstacles may exist that create the hazard of collision. The invention may therefore be further modified to incorporate any suitable on-board collision avoidance system, such as those based on scanning lidar, radar, visual or ultrasonic ranging, etc., as are known in the art.
Example
(53) The preceding examples in many cases contemplate that the sampling uses one or more sampling cartridges 10, which are generally contemplated to be single-use, disposable, or partially disposable. That is to say, when a cartridge is sent for analysis, the testing laboratory might discard the used cartridge; alternatively, it might disassemble the cartridge, remove the test article (e.g., the filter medium), and perhaps reassemble the cartridge with a new test article in a re-used housing. Thus, the amount of any cartridge that is configured or intended to be re-used may vary depending on the particular trade-offs of economics, labor, and contamination or cleaning issues that might be involved.
Example
(54) The Invention may also be configured to perform analyses in real time or near real time, by replacing the sample cartridge(s) with a test cell that can perform some physical test in the flowing air without the need to capture a sample for analysis off-line. Applicant contemplates many uses for this variant. For example, sensitive gas sensors are well known in the art, which are optimized for particular gases or vapors (e.g., ethanol, hydrogen, CO, combustible gases, etc.). Thus, the cartridge may be replaced with a flow cell in which a combustible gas sensor is operating, and the sUAS could then be used to survey an area for hazardous gas leaks (e.g., the site of a railroad accident involving tankers of volatile substances. In another contemplated application, the flow cell may include an optical scattering detector that would quantify the level of smoke, dust, water vapor, or other items of interest for applications in meteorology, environmental monitoring, regulatory compliance, and the like.
(55) As described in the examples, an essential feature of the invention is the collection of samples at a plurality of well-defined geolocations. Although for convenience, some of the foregoing examples refer to GPS as a shorthand for geolocation information, it will be understood that the standard Global Positioning System is only one of several geolocation protocols. Furthermore, if the sUAS is operating inside of a building or enclosed space, it might be more accurate and convenient to deploy an ultrasonic triangulation system within the working space. Any suitable means for determining the location of each sample within a suitable geospatial coordinate system at an acceptable level of accuracy may be used, and all such means are considered to be within the scope of the invention.
(56) As described in several of the examples, Applicant contemplates that the sUAS will, in general, move from place to place and then remain or loiter at selected locations for a sufficient time to collect a valid sample. The sUAS may loiter by hovering in place while the sample is collected; alternatively, the vehicle might land and collect a sample while completely stationary (e.g., at selected places on the roof of a building near air conditioning towers, etc.) For the case in which real-time or near real-time sampling is done, as in the case of continuously monitoring the atmosphere as it flows through a tube, then the loitering time may be very short in that the sUAS might be continuously moving at a low speed. In such cases, the time stamp would be associated with a geolocation that includes a volume of space defined by the speed of the vehicle and the time to collect a measurement.
IDENTIFICATION OF COMPONENTS BY REFERENCE NUMERAL
(57) Item Description 1 Propeller 2 Motor 3 Frame Arm 4 Navigation and Radio 6 Controller 6 Power 7 Payload Support 8 Intake Pipe 9 Connecting Pipe 10 Sample Cartridge 11 Blower Case 12 Servo 13 Base Plate 14 Rotary Cartridge Holder 15 Ground Control 31 Voltage Regulator 32 Voltage Regulator Attached to Blower Exhaust 41 Magazine 41 Drum Magazine 42 Spring 43 Spring Plate 44 Actuator Plate 45 Actuator 61 Unloading Cartridge Telescoping Arm 62 Loading Cartridgo Plate 63 Telescoping Loading Arm 64 Servo Motor Hub 65 Spring Hub 66 Unloading Carriage Plate 71 Blower Exhaust 72 Blower Intake 81 Blower Hub 82 Backward Facing Blade 82 Forward Facing Blade 82 Axial Blade 121 Shroud Attached to Blade