Upload
herbert-walsh
View
213
Download
0
Embed Size (px)
Citation preview
Mist GeneratorMist Generator
Kelly Toy Jon CappelKelly Toy Jon Cappel
Joe Bothwell Abdikarim MahamudJoe Bothwell Abdikarim Mahamud
Advisor – John Webster
Client – Jack Jiang, MD, PhD
http://www.rcjournal.com/contents/06.00/06.00.0609.asp.
University of Wisconsin - Madison Biomedical Engineering Design Courses
INTELLECTUAL PROPERTY STATEMENT
All information provided by individuals or Design Project Groups during this or subsequent presentations is the property of the University and of the researchers presenting this information. In addition, any information provided herein may include results sponsored by and provided to a member company of the Biomedical Engineering Student Design Consortium (SDC). The above information may include intellectual property rights belonging to the University to which the SDC may have license rights. Anyone to whom this information is disclosed: 1) Agrees to use this information solely for purposes related to this review; 2) Agrees not to use this information for any other purpose unless given written
approval in advance by the Project Group, the Client / SDC, and the Advisor. 3) Agrees to keep this information in confidence until the University and the
relevant parties listed in Part (2) above have evaluated and secured any applicable intellectual property rights in this information.
4) Continued attendance at this presentation constitutes compliance with this
agreement.
OverviewOverview
Problem StatementProblem Statement
Background MaterialBackground Material
Summary of product design specificationsSummary of product design specifications
Design Alternatives consideredDesign Alternatives considered
Future WorkFuture Work
Problem StatementProblem Statement
Research being conducted on the larynx Research being conducted on the larynx can be benefited by the specific targeting of can be benefited by the specific targeting of medication in the respiratory systemmedication in the respiratory system
Specific targeting of medication is difficult to Specific targeting of medication is difficult to complete accuratelycomplete accurately
The process of atomizing particles is The process of atomizing particles is complexcomplex
Client RequirementClient Requirement
-Product is needed that can:-Product is needed that can:Generate a mist of different densitiesGenerate a mist of different densities
Generate particle sizes in the range of 0.5-50 Generate particle sizes in the range of 0.5-50 micronsmicrons
Adaptable as inhalerAdaptable as inhaler
Generate mist such that different areas of the Generate mist such that different areas of the respiratory system can be targetedrespiratory system can be targeted
BackgroundBackground
Different ways to generate mist:Different ways to generate mist:– Ultrasonic NebulizerUltrasonic Nebulizer– MicropumpsMicropumps– Pressure activated devicesPressure activated devices
Particle measurement techniquesParticle measurement techniques
Ultrasonic NebulizerUltrasonic NebulizerConverts electricity into Converts electricity into ultrasonic waves ultrasonic waves Transducer vibrates at Transducer vibrates at frequency of waves (1-3 frequency of waves (1-3 MHz)MHz)Higher the frequency, Higher the frequency, smaller dropletssmaller dropletsTransducer generates Transducer generates ultrasonic fountain of liquidultrasonic fountain of liquidAerosol delivered by fan or Aerosol delivered by fan or inspirationinspirationCreates particles ~1-6 Creates particles ~1-6 micronsmicrons
Dennis J, Hendrick DDennis J, Hendrick D
Ultrasonic NebulizerUltrasonic NebulizerAdvantages/DisadvantagesAdvantages/DisadvantagesAdvantagesAdvantages
Stable particle sizeStable particle sizeSmall dead volumeSmall dead volumeHigh aerosol outputHigh aerosol outputQuietQuietFast drug deliveryFast drug delivery
DisadvantagesDisadvantagesAerosol solution can become Aerosol solution can become heatedheatedExpensiveExpensiveShort cycle life (600-1000 Short cycle life (600-1000 uses)uses)
http://www.mabis.net/40-270-Open/
MicropumpsMicropumps
OnQ is one of the micropumps OnQ is one of the micropumps used in the market for used in the market for nebulizers. nebulizers. contains over a thousand contains over a thousand precision-formed tapered precision-formed tapered holes, surrounded by a holes, surrounded by a vibrational element. vibrational element. plate vibrates over 100,000 plate vibrates over 100,000 times per second.times per second.It draws liquid through the It draws liquid through the holes to form consistently holes to form consistently sized droplets. sized droplets.
Problems Problems How to adjust the frequency.How to adjust the frequency.
http://http://www.aerogen.comwww.aerogen.com
Pressure Activated DevicesPressure Activated Devices
Devices that create mist by using pressure– Inhalers use a similar principle
hand-held portable devices that deliver medication directly to the lungs
Uses pressurized canister with chemical propellant
http://www.aaaai.org/patients/allergic_conditions/metered_dose_inhalers.stm
Pressure Activated DevicesPressure Activated Devices
Devices similar to hairspray Devices similar to hairspray bottlesbottles– Use pressure to compress liquidUse pressure to compress liquid– Liquid is compressed through tiny Liquid is compressed through tiny
opening creating mistopening creating mist
http://www.atomization.de/basic.htm#Physical
http://www.drugstore.com/
Pressure Activated DevicesPressure Activated Devices
AdvantagesAdvantages– InexpensiveInexpensive– SimpleSimple
DisadvantagesDisadvantages– Comparatively, very large mist particlesComparatively, very large mist particles– Different nozzles needed for different Different nozzles needed for different
densitiesdensities
Particle measurement techniquesParticle measurement techniquesLaser DiffractionLaser Diffraction– Method is absolute, no need to calibrate instrumentsMethod is absolute, no need to calibrate instruments– Wide range .01-2000 micronsWide range .01-2000 microns– Flexibility, paint nozzle sprays to dry powderFlexibility, paint nozzle sprays to dry powder– Can measure circulating liquid particles.Can measure circulating liquid particles.– Requires expensive equipmentRequires expensive equipment– Engine research lab has a Malvern laser diffraction Engine research lab has a Malvern laser diffraction
instrument instrument MicroscopyMicroscopy– Relies on microscope, and precision measuring Relies on microscope, and precision measuring
devices.devices.– Somewhat prone to error due to the judgment of the Somewhat prone to error due to the judgment of the
operator. operator.
Particle measurement techniquesParticle measurement techniques
Cascade impactorCascade impactor– Progressively filters out smaller particles through a Progressively filters out smaller particles through a
series of tubes.series of tubes.– Particles accumulate according to their size, and Particles accumulate according to their size, and
the concentrations are analyzed after the the concentrations are analyzed after the experimentexperiment
– Can take a relatively long time to completeCan take a relatively long time to completeElectrozone sensingElectrozone sensing– Changes in capacitance are measured as a Changes in capacitance are measured as a
charged particle flows through a small opening.charged particle flows through a small opening.– Extremely difficult/near impossible to measure Extremely difficult/near impossible to measure
sprays.sprays.
Design AlternativesDesign Alternatives
1.Modify a Nebulizer1.Modify a Nebulizer– Adjust pressure inputAdjust pressure input– Adjust vibration frequencyAdjust vibration frequency– Apply a charge to solutionApply a charge to solution– Adjust opening sizeAdjust opening size– Particle size selectorParticle size selector– Requires monetary investmentRequires monetary investment
Design AlternativesDesign Alternatives
2.Create our own simple device2.Create our own simple device– Use the most simple aspects of fluid Use the most simple aspects of fluid
mechanicsmechanics– Obtain an actuator, and force liquid through it Obtain an actuator, and force liquid through it
at different pressures.at different pressures.
3.Purchase existing components 3.Purchase existing components – May require slight modificationsMay require slight modifications– Extremely expensiveExtremely expensive
Design/Decision MatrixDesign/Decision MatrixNebulizerNebulizer Our DeviceOur Device PurchasePurchase
AccuracyAccuracy 55 66 99
ComplexityComplexity
(ease of use)(ease of use)
55 88 33
PricePrice 55 77 11
Life spanLife span 66 66 77
TotalTotal 2525 2626 2020
Final Design ChoiceFinal Design Choice
Create our own simple device.Create our own simple device.– We will force liquid through different sized We will force liquid through different sized
actuators, and experimentally determine what actuators, and experimentally determine what size and pressures will obtain the required size and pressures will obtain the required particle size.particle size.
Easy to modify if neededEasy to modify if needed
Relies only on pressure and actuator openingRelies only on pressure and actuator opening
Future WorkFuture Work
Obtain different sized actuatorsObtain different sized actuators
Develop a method for subjecting liquid to Develop a method for subjecting liquid to specific pressure levels.specific pressure levels.
Develop a prototype Develop a prototype
Perform experimentsPerform experiments
Analyze results.Analyze results.
ReferencesReferences
Basic principals of particle size measurement, Dr. Alan Rawle, Malvern Basic principals of particle size measurement, Dr. Alan Rawle, Malvern Instruments limitedInstruments limited
http://www.tsi.com/particle/products/accessories/376060.htmhttp://www.tsi.com/particle/products/accessories/376060.htm
http://www.atomization.de/basic.htm#Physicalhttp://www.atomization.de/basic.htm#Physical
Hess D. Nebulizers: Principles and Performance. Respiratory Care. Hess D. Nebulizers: Principles and Performance. Respiratory Care. http://www.rcjournal.com/contents/06.00/06.00.0609.asp. 2 March 2004http://www.rcjournal.com/contents/06.00/06.00.0609.asp. 2 March 2004
Dennis J, Hendrick D. Design of drug nebulizers. Journal of Aerosol Dennis J, Hendrick D. Design of drug nebulizers. Journal of Aerosol Science. 2000;Sep:S787-s789.Science. 2000;Sep:S787-s789.this one is for picturethis one is for picture
American Academy of Asthma and Allergy Immunity American Academy of Asthma and Allergy Immunity http://www.aaaai.org/patients/allergic_conditions/metered_dose_inhalers.sthttp://www.aaaai.org/patients/allergic_conditions/metered_dose_inhalers.stm 2004m 2004
Aerogen, 2004 http://www.aerogen.com/Aerogen, 2004 http://www.aerogen.com/