http://www.rcjournal.com/con tents/06.00/06.00.0609.asp.
Kelly Toy Jon Cappel
Joe Bothwell Abdikarim Mahamud
Advisor – John Webster
Client – Jack Jiang, MD, PhD

University of Wisconsin - Madison
Biomedical Engineering Design Courses
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Problem Statement
Background Material
Summary of product design specifications
Design Alternatives considered
Future Work

Research being conducted on the larynx can be benefited by the specific targeting of medication in the respiratory system
Specific targeting of medication is difficult to complete accurately
The process of atomizing particles is complex

-Product is needed that can:
Generate a mist of different densities
Generate particle sizes in the range of 0.5-50 microns
Adaptable as inhaler
Generate mist such that different areas of the respiratory system can be targeted

Different ways to generate mist:
– Ultrasonic Nebulizer
– Micropumps
– Pressure activated devices
Particle measurement techniques

Converts electricity into ultrasonic waves
Transducer vibrates at frequency of waves (1-3
MHz)
Higher the frequency, smaller droplets
Transducer generates ultrasonic fountain of liquid
Aerosol delivered by fan or inspiration
Creates particles ~1-6 microns
Dennis J, Hendrick D

Advantages
Stable particle size
Small dead volume
High aerosol output
Quiet
Fast drug delivery
Disadvantages
Aerosol solution can become heated
Expensive
Short cycle life (600-1000 uses) http://www.mabis.ne
t/40-270-Open/

OnQ is one of the micropumps used in the market for nebulizers. contains over a thousand precision-formed tapered holes, surrounded by a vibrational element. plate vibrates over 100,000 times per second.
It draws liquid through the holes to form consistently sized droplets.
Problems
How to adjust the frequency.
http://www.aerogen.com

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_c onditions/metered_dose_inhalers.stm

Devices similar to hairspray bottles
– Use pressure to compress liquid
– Liquid is compressed through tiny opening creating mist http://www.drugstore.com/ http://www.atomization.de/basic.htm#Physical

Advantages
– Inexpensive
– Simple
Disadvantages
– Comparatively, very large mist particles
– Different nozzles needed for different densities

Laser Diffraction
– Method is absolute, no need to calibrate instruments
– Wide range .01-2000 microns
– Flexibility, paint nozzle sprays to dry powder
– Can measure circulating liquid particles.
– Requires expensive equipment
– Engine research lab has a Malvern laser diffraction instrument
Microscopy
– Relies on microscope, and precision measuring devices.
– Somewhat prone to error due to the judgment of the operator.

Cascade impactor
– Progressively filters out smaller particles through a series of tubes.
– Particles accumulate according to their size, and the concentrations are analyzed after the experiment
– Can take a relatively long time to complete
Electrozone sensing
– Changes in capacitance are measured as a charged particle flows through a small opening.
– Extremely difficult/near impossible to measure sprays.

1.Modify a Nebulizer
– Adjust pressure input
– Adjust vibration frequency
– Apply a charge to solution
– Adjust opening size
– Particle size selector
– Requires monetary investment

2.Create our own simple device
– Use the most simple aspects of fluid mechanics
– Obtain an actuator, and force liquid through it at different pressures.
3.Purchase existing components
– May require slight modifications
– Extremely expensive

Accuracy
Nebulizer Our Device Purchase
5 6 9
8 3 Complexity
(ease of use)
Price
5
5
Life span 6
Total 25
7
6
26
1
7
20

Create our own simple device.
– We will force liquid through different sized actuators, and experimentally determine what size and pressures will obtain the required particle size.
Easy to modify if needed
Relies only on pressure and actuator opening

Obtain different sized actuators
Develop a method for subjecting liquid to specific pressure levels.
Develop a prototype
Perform experiments
Analyze results.

Basic principals of particle size measurement, Dr. Alan Rawle, Malvern
Instruments limited http://www.tsi.com/particle/products/accessories/376060.htm
http://www.atomization.de/basic.htm#Physical
Hess D. Nebulizers: Principles and Performance. Respiratory
Care. http://www.rcjournal.com/contents/06.00/06.00.0609.asp. 2 March
2004
Dennis J, Hendrick D. Design of drug nebulizers. Journal of Aerosol
Science. 2000;Sep:S787-s789.
this one is for picture
American Academy of Asthma and Allergy Immunity http://www.aaaai.org/patients/allergic_conditions/metered_dose_inhalers.st
m 2004
Aerogen, 2004 http://www.aerogen.com/