NonElectronic Oxygen Analyzer for Oxygen Concentrator Systems

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Non-Electronic Oxygen Analyzer for Oxygen
Concentrator Systems

• Damien Pechak
• Group 11
• October 4, 2006
• Team Members Hannah Jacobs-El, Ivan Dimitrov
• Mentor Dr. David Sept

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Outline

• Background and Need
• Present Solutions
• Design Specifications
• Preliminary Analysis
• Design Schedule
• Team Organization

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Why An Alternative Oxygen Analyzer is Needed

• Developing Nations
• Acute respiratory infections are major cause of
  death in early childhood
• 2 million children die each year due to
  pneumonia1
• Hypoxemia symptoms
• 47 of hospitalized children with ARI also
  developed hypoxemia2
• Hypoxemia can increase the risk of death nearly 5
  times
• Treatment for hypoxemia, oxygen therapy, is
  limited due to difficulties in maintaining an
  oxygen supply in developing nations3

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Why An Alternative Oxygen Analyzer is Needed

• Oxygen Concentrators can increase amount of
  oxygen therapy offered
• With power source provide an unlimited supply of
  90-95 O2
• Economical alternative to cylinders
• Caveats
• Oxygen concentration levels can vary if machine
  isnt well maintained3
• Oxygen concentration levels must be evaluated
  periodically to ensure patients receive
  appropriate amounts of oxygen4
• Typical oxygen concentration analyzers are
  electronic devices not designed for extreme
  environmental conditions

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Background The Oxygen Concentrator System5

• Compressor
• Compresses room air to 140 kPa
• Filters remove dust and bacteria in room air
• Zeolite Molecular Sieves
• N2 molecules adsorb to the crystalline structure
  as the pressurized air flows through it
• Two sieve beds are used in pressure swing
  adsorption process (PSA)
• Reservoir
• Collects O2 rich output
• Flow meter regulates continuous output flow from
  system
• 0.5 5 L/min flow of 90 95 O2

Reproduced from Hess, Dean R. et. Al.5
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Present Solutions Oxygen Analyzers

• Many means of determining Oxygen concentrations
• Four common types of oxygen analyzer
• Electrochemical
• Paramagnetic
• Wheatstone Bridge
• Zirconium Oxide

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Electrochemical Oxygen Analyzers6

• Redox Reaction Principles
• Two types Galvanic and Polarographic
• Anode and Cathode
• O2 is reduced at cathode removing electrons
• Anode is oxidized by chloride or hydroxide ions
  producing electrons
• Meter
• Current between anode and cathode is converted to
  O2 concentration
• Battery
• Polarographic (Clark) cells also have a battery
  to polarize the electrodes increasing response
  times
• Disadvantages
• Cell must be replaced periodically
• Humidity affects measurements
• Sensitive to partial pressures rather than
  concentrations

Reproduced from Fraden, Jacob 7
Reproduced from Wilkins, Robert L, et al8
Patent 7,025,870
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Paramagnetic Oxygen Analyzers9,10

• Based on Pauling Principle
• O2 is paramagnetic while N2 is diamagnetic
• Dumbbell Design
• Filled with N2, suspended by thin fiber
• Magnetic Poles
• Field density around dumbbell changes as O2
  reacts to magnetic field
• Mirror
• Moves with dumbbell and reflects light along a
  scale calibrated for O2 concentration
• Disadvantages
• Vary delicate

Reproduced from White, Gary10
Patents 7,081,745 4,464,926
Reproduced from White, Gary7
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Wheatstone Bridge Oxygen Analyzer10

• Thermoconductivity principles
• O2 conducts heat faster than N2
• 4 Thermistors
• Wheatstone bridge arrangement allows detection of
  small fluctuations in resistance
• Two Gas Chambers
• O2 concentration difference between unknown and
  reference gas results in difference in resistance
  due to its effect on heat transfer
• Disadvantages
• Not safe in flammable environments (anesthesia)

Reproduced from White, Gary10
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Zirconium Oxide Oxygen Analyzers12

• Based on electrochemical reactions
• Redox reactions at anode and cathode
• Zirconium oxide
• Heating element heats to 650C at which point
  oxygen ions conduct electrons between the two
  electrodes
• Platinum electrodes
• Outside surface reference gas
• Inside surface gas being measured
• Reduction of O2 at cathode and oxidation at anode
  produce a current which is read by ammeter
  calibrated for O2 concentration
• Disadvantages
• Shorter lifetime due to constant heating and
  cooling
• Sensitive to partial pressures rather than
  concentration
• Not safe in flammable environments

Reproduced from Delta F corporation13
Patents 4,995,256 5,518,603
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Specifications
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Preliminary Analysis

• Solution is likely to based on chemical reaction,
  requiring knowledge of the amount of O2
• The effects of Pressure, Temperature, and Flow
  Rate are described easily with the ideal gas law
• Valid for Temperatures above freezing 0C,
  pressures below sea level (1 atm)
• The minimum number of moles is produced at 4000m
  (PO2 13kPa), high temperature (313K), and lowest
  flow rates (21 of .5L/min)
• The maximum number of moles is produced at sea
  level (PO221kPa), low temperature (273K), and
  highest flow rates (5L/min)

Sea level
4000m
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Team Organization

• Damien Pechak
• Preliminary presentation
• Materials Research
• Hannah Jacobs-El
• Progress presentation
• Mathematical analysis
• Website
• Ivan Dimitrov
• Final Presentation
• Chemical Reaction Research

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References

• 1) Wardlaw, Tessa, Emily White Johansson,
  Matthew Hodge, 2006, Pneumonia the Forgotten
  Killer of Children, The United Nations Childrens
  Fund (UNICEF)/World Health Organization (WHO),
  WHO press, Geneva.
• 2) Lozano, J.M., 2001, Epidemiology of
  Hypoxaemia in Children with Acute Lower
  Respiratory Infection, International Journal of
  Tuberculosis and Lung Disease, 5(6), pp 496-504.
• 3) Shrestha, Bisharad M., Birendra B. Singh,
  Madhav P. Gautam, Man B. Chand, 2002, The Oxygen
  Concentrator is a Suitable Alternative to Oxygen
  Cylinders in Nepal, Canadian Journal of
  Anesthesiology, 49(1 ), pp 812.
• 4) Product Information Sheets, 2000, World
  Health Organization, Department of Vaccines and
  Biologicals, WHO press, Geneva.
• 5) Hess, Dean R., Neil R. MacIntyre, Shelley C.
  Mishoe, William F. Galvin, Alexander B. Adams,
  Allan B. Saposnick, 2002, Respiratory Care
  Principles and Practice, W.B. Saunders Company,
  Philadelphia.
• 6) Kacmarek, Robert M., Steven Dimas, Caig W.
  Mack, 2005, The Essentials of Respiratory Care,
  4th ed., Mosby, Inc., St. Louis.
• 7) Fraden, Jacob, 2004, Handbook of Modern
  Sensors Physics, designs, and Applications, 3rd
  ed., Springer-Verlag, Inc., New York.
• 8) Wilkins, Robert L., James K. Stoller, Craig
  L. Scanlan, 2003, Egans Fundamentals of
  Repiratory Care, 8th ed., Mosby, Inc., St.
  Louis.
• 9) Cairo, J.M., Susan P. Pilbeam, 2004, Mosbys
  Respiratory Equipment, 7th ed., Mosby, Inc., St.
  Louis.
• 10) White, Gary C., 1992, Equipment Theory for
  Respiratory Care, Delmar Publishers, Inc.,
  Albany.
• 11) Carr, Gayle, Oxygen Analyzers,
  http//faculty.icc.edu/gcarr/equip-OA.htm
• 12) Norton, Harry N., 1982, Sensor and Analyzer
  Handbook, Prentice-Hall, Inc., Englewood Cliffs.
• 13) Delta F Corportation, Non-depleting
  Coulometric, http//www.delta-f.com/O2Guide/O2Gui
  deZirc.html
• 14) Oxygen Therapy for Children With Acute
  Respiratory Infections in Developing Nations,
  1993, World Health Organization (WHO), WHO press,
  Geneva.

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Questions?